text:
// The list of external handlers is from the ARM assembly startup files.

// ----------------------------------------------------------------------------

#include <cmsis-plus/cortexm/exception-handlers.h>

// ----------------------------------------------------------------------------

void __attribute__((weak))
Default_Handler(void);

// Forward declaration of the specific IRQ handlers. These are aliased
// to the Default_Handler, which is a 'forever' loop. When the application
// defines a handler (with the same name), this will automatically take
// precedence over these weak definitions

void __attribute__ ((weak, alias ("Default_Handler")))
WWDG_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
PVD_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TAMP_STAMP_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
RTC_WKUP_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
FLASH_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
RCC_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
EXTI0_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
EXTI1_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
EXTI2_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
EXTI3_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
EXTI4_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream0_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream1_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream2_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream3_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream4_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream5_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream6_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
ADC_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN1_TX_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN1_RX0_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN1_RX1_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN1_SCE_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
EXTI9_5_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM1_BRK_TIM9_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM1_UP_TIM10_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM1_TRG_COM_TIM11_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM1_CC_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM2_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM3_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM4_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
I2C1_EV_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
I2C1_ER_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
I2C2_EV_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
I2C2_ER_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
SPI1_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
SPI2_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
USART1_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
USART2_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
USART3_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
EXTI15_10_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
RTC_Alarm_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
OTG_FS_WKUP_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM8_BRK_TIM12_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM8_UP_TIM13_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM8_TRG_COM_TIM14_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM8_CC_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA1_Stream7_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
FMC_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
SDIO_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM5_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
SPI3_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
UART4_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
UART5_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM6_DAC_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
TIM7_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream0_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream1_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream2_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream3_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream4_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
ETH_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
ETH_WKUP_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN2_TX_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN2_RX0_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN2_RX1_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
CAN2_SCE_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
OTG_FS_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream5_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream6_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DMA2_Stream7_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
USART6_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
I2C3_EV_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
I2C3_ER_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
OTG_HS_EP1_OUT_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
OTG_HS_EP1_IN_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
OTG_HS_WKUP_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
OTG_HS_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
DCMI_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
HASH_RNG_IRQHandler(void);
void __attribute__ ((weak, alias ("Default_Handler")))
FPU_IRQHandler(void);

// ----------------------------------------------------------------------------

extern unsigned int _estack;

typedef void
(* const pHandler)(void);

// ----------------------------------------------------------------------------

// The table of interrupt handlers. It has an explicit section name
// and relies on the linker script to place it at the correct location
// in memory.

__attribute__ ((section(".isr_vector"),used))
pHandler __isr_vectors[] =
  {
    // Cortex-M Core Handlers
    (pHandler) &_estack,               // The initial stack pointer
    Reset_Handler,                     // The reset handler

    NMI_Handler,                       // The NMI handler
    HardFault_Handler,                 // The hard fault handler

#if defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__)
    MemManage_Handler,                 // The MPU fault handler
    BusFault_Handler,                  // The bus fault handler
    UsageFault_Handler,                // The usage fault handler
#else
    0,                                 // Reserved
    0,                                 // Reserved
    0,                                 // Reserved
#endif
    0,                                 // Reserved
    0,                                 // Reserved
    0,                                 // Reserved
    0,                                 // Reserved
    SVC_Handler,                       // SVCall handler
#if defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7EM__)
    DebugMon_Handler,                  // Debug monitor handler
#else
    0,                                 // Reserved
#endif
    0,                                 // Reserved
    PendSV_Handler,                    // The PendSV handler
    SysTick_Handler,                   // The SysTick handler

    // ----------------------------------------------------------------------
    // External Interrupts
    WWDG_IRQHandler,                   // Window WatchDog
    PVD_IRQHandler,                    // PVD through EXTI Line detection
    TAMP_STAMP_IRQHandler,             // Tamper and TimeStamps through the EXTI line
    RTC_WKUP_IRQHandler,               // RTC Wakeup through the EXTI line
    FLASH_IRQHandler,                  // FLASH
    RCC_IRQHandler,                    // RCC
    EXTI0_IRQHandler,                  // EXTI Line0
    EXTI1_IRQHandler,                  // EXTI Line1
    EXTI2_IRQHandler,                  // EXTI Line2
    EXTI3_IRQHandler,                  // EXTI Line3
    EXTI4_IRQHandler,                  // EXTI Line4
    DMA1_Stream0_IRQHandler,           // DMA1 Stream 0
    DMA1_Stream1_IRQHandler,           // DMA1 Stream 1
    DMA1_Stream2_IRQHandler,           // DMA1 Stream 2
    DMA1_Stream3_IRQHandler,           // DMA1 Stream 3
    DMA1_Stream4_IRQHandler,           // DMA1 Stream 4
    DMA1_Stream5_IRQHandler,           // DMA1 Stream 5
    DMA1_Stream6_IRQHandler,           // DMA1 Stream 6
    ADC_IRQHandler,                    // ADC1, ADC2 and ADC3s
    CAN1_TX_IRQHandler,                // CAN1 TX
    CAN1_RX0_IRQHandler,               // CAN1 RX0
    CAN1_RX1_IRQHandler,               // CAN1 RX1
    CAN1_SCE_IRQHandler,               // CAN1 SCE
    EXTI9_5_IRQHandler,                // External Line[9:5]s
    TIM1_BRK_TIM9_IRQHandler,          // TIM1 Break and TIM9
    TIM1_UP_TIM10_IRQHandler,          // TIM1 Update and TIM10
    TIM1_TRG_COM_TIM11_IRQHandler,     // TIM1 Trigger and Commutation and TIM11
    TIM1_CC_IRQHandler,                // TIM1 Capture Compare
    TIM2_IRQHandler,                   // TIM2
    TIM3_IRQHandler,                   // TIM3
    TIM4_IRQHandler,                   // TIM4
    I2C1_EV_IRQHandler,                // I2C1 Event
    I2C1_ER_IRQHandler,                // I2C1 Error
    I2C2_EV_IRQHandler,                // I2C2 Event
    I2C2_ER_IRQHandler,                // I2C2 Error
    SPI1_IRQHandler,                   // SPI1
    SPI2_IRQHandler,                   // SPI2
    USART1_IRQHandler,                 // USART1
    USART2_IRQHandler,                 // USART2
    USART3_IRQHandler,                 // USART3
    EXTI15_10_IRQHandler,              // External Line[15:10]s
    RTC_Alarm_IRQHandler,              // RTC Alarm (A and B) through EXTI Line
    OTG_FS_WKUP_IRQHandler,            // USB OTG FS Wakeup through EXTI line
    TIM8_BRK_TIM12_IRQHandler,         // TIM8 Break and TIM12
    TIM8_UP_TIM13_IRQHandler,          // TIM8 Update and TIM13
    TIM8_TRG_COM_TIM14_IRQHandler,     // TIM8 Trigger and Commutation and TIM14
    TIM8_CC_IRQHandler,                // TIM8 Capture Compare
    DMA1_Stream7_IRQHandler,           // DMA1 Stream7
    FMC_IRQHandler,                    // FMC
    SDIO_IRQHandler,                   // SDIO
    TIM5_IRQHandler,                   // TIM5
    SPI3_IRQHandler,                   // SPI3
    UART4_IRQHandler,                  // UART4
    UART5_IRQHandler,                  // UART5
    TIM6_DAC_IRQHandler,               // TIM6 and DAC1&2 underrun errors
    TIM7_IRQHandler,                   // TIM7
    DMA2_Stream0_IRQHandler,           // DMA2 Stream 0
    DMA2_Stream1_IRQHandler,           // DMA2 Stream 1
    DMA2_Stream2_IRQHandler,           // DMA2 Stream 2
    DMA2_Stream3_IRQHandler,           // DMA2 Stream 3
    DMA2_Stream4_IRQHandler,           // DMA2 Stream 4
    ETH_IRQHandler,                    // Ethernet
    ETH_WKUP_IRQHandler,               // Ethernet Wakeup through EXTI line
    CAN2_TX_IRQHandler,                // CAN2 TX
    CAN2_RX0_IRQHandler,               // CAN2 RX0
    CAN2_RX1_IRQHandler,               // CAN2 RX1
    CAN2_SCE_IRQHandler,               // CAN2 SCE
    OTG_FS_IRQHandler,                 // USB OTG FS
    DMA2_Stream5_IRQHandler,           // DMA2 Stream 5
    DMA2_Stream6_IRQHandler,           // DMA2 Stream 6
    DMA2_Stream7_IRQHandler,           // DMA2 Stream 7
    USART6_IRQHandler,                 // USART6
    I2C3_EV_IRQHandler,                // I2C3 event
    I2C3_ER_IRQHandler,                // I2C3 error
    OTG_HS_EP1_OUT_IRQHandler,         // USB OTG HS End Point 1 Out
    OTG_HS_EP1_IN_IRQHandler,          // USB OTG HS End Point 1 In
    OTG_HS_WKUP_IRQHandler,            // USB OTG HS Wakeup through EXTI
    OTG_HS_IRQHandler,                 // USB OTG HS
    DCMI_IRQHandler,                   // DCMI
    0,                                 // Reserved
    HASH_RNG_IRQHandler,               // Hash and Rng
    FPU_IRQHandler,                    // FPU
};

// ----------------------------------------------------------------------------

// Processor ends up here if an unexpected interrupt occurs or a
// specific handler is not present in the application code.
// When in DEBUG, trigger a debug exception to clearly notify
// the user of the exception and help identify the cause.

void __attribute__ ((section(".after_vectors")))
Default_Handler(void)
{
#if defined(DEBUG)
__DEBUG_BKPT();
#endif
while (1)
  {
  }
}

// ----------------------------------------------------------------------------

redpajama_set_name: RedPajamaGithub


About Magazine, the magazine dedicated to positive change! About is written and contributed to by individuals, groups, and organizations committed to positive change. The articles and viewpoints expressed are not necessarily the opinion of About Magazine its staff, the other groups, organizations, companies and/or individuals involved in or contributing to this magazine or advertising within it. We welcome feedback from our readers and if you'd like more information from any of our contributors; links are provided at the end of every article.


Candlewick : colored and decorated lines / Myrna and Bob Garrison.
"Part of this book appeared in a slightly different version in Milk glass: Imperial Glass Corporation, plus opaque, slag and more c2001... and Imperial's candlewick: little known facts c1999"--T.p. verso.
Includes bibliographical references (p. ) index.
Pt. V. Miscellaneous candlewick and Imperial.


text:
Scott Pilgrim vs. The World Headlines Pictures Videos
A young man (Michael Cera) must fight a girl's (Mary Elizabeth Winstead) seven sinister ex-boyfriends in order to win her hand in this Universal Pictures adaptation of Bryan Lee O'Malley's Oni Press comic book. Shaun of the Dead's Edgar Wright directs from a script he penned with Michael Bacall. Superhero veterans Chris Evans and Brandon Routh co-star in the action comedy as two of the seven ex-boyfriends.
SCOTT PILGRIM Netflix Animated Series In The Works With Creator Bryan Lee O'Malley On Board
Netflix and UCP (The Umbrella Academy, Chucky) are developing a new anime series based on acclaimed comic book Scott Pilgrim, with creator/artist Bryan Lee O'Malley on board as executive producer.
MattIsForReal
SCOTT PILGRIM VS. THE WORLD Returning To Dolby Cinema This April After Delayed 10th Anniversary Re-Release
After its 10th Anniversary re-release was delayed, Scott Pilgrim vs. The World will finally return to theaters, reimagined in Dolby Vision and Dolby Atmos. Check out the exciting trailer and poster below!
10 CLOVERFIELD LANE And SCOTT PILGRIM Star Mary Elizabeth Winstead Strips Off For New Photoshoot
Hot off the news that she's joined the cast of Fargo season three, Mary Elizabeth Winstead has stripped down for a VVV Magazine photoshoot. Hit the jump to check the NSFW images out...
SCOTT PILGRIM's Anna Kendrick Is Nuts About The Idea Of Playing SQUIRREL GIRL For Marvel
Fans have wanted to see Anna Kendrink (Scott Pilgrim Vs. The World) play a superhero for quite a while, and it turns out she is interested in one awesomely silly character in particular...
BawbScharf
The Next Blockbuster Franchise and Ideal Director
In the day and age of a Star Wars movie each year, Cameron planning four Avatar sequels, Phantom Menacing every BVS snippet, and everything being in a shared Cinematic, it needs to be asked "what is next?" Understanding that Hollywood likes proven brands, we need to look towards what franchise could open up a whole new world of possibilities ...and why there is only one Director/Producer that can do the franchise right.
MarkJulian
Universal Studios' Head Honcho Ron Meyer, "We make a lot of sh*tty movies."
Universal Pictures' President Ron Meyer on 3-D, The Wolfman, Scott Pilgrim, and Cowboys & Aliens.
WaylonJones
Immortals B-Roll Footage
Check out some behind the scenes footage from the upcoming Greek fantasy film directed by Tarsem Singh, Immortals. Featuring Henry Cavill and crew in action along with a look at them preparing for a fight scene.
Chris Evans Talks Scott Pilgrim And Fears That Captain America Would Bomb!
The Avengers star expresses his fears that Captain America: The First Avenger would fail to be as successful as Iron Man and THOR, as well as expressing his anger over the box office failure of Scott Pilgrim...
New Cowboys & Aliens Featurette
The cast and crew of the upcoming sci-fi western discuss the "genre mash-up" phenomenon unfolding in the film. Hear exerts from Olivia Wilde, Jon Favreau, Daniel Craig, Ron Howard,Harrison Ford, and many others.
Edgar Wright Walks Away With 'Best Director' At 2011 Empire Awards!
The Scott Pilgrim Vs. The World director was named 'Best Director' at this years Empire awards, and Kick-Ass did pretty well too! Hit the jump for the full results...

redpajama_set_name: RedPajamaCommonCrawl


text:
De Bv P.179 was een project voor een jachtbommenwerper dat werd ontwikkeld door de Duitse vliegtuigbouwer Blohm und Voss.

Ontwikkeling
Het toestel was van een asymmetrisch ontwerp en was een verdere ontwikkeling van de Bv P.177.

De motor was een luchtgekoelde dubbele BMW 801-stermotor met veertien cilinders. Deze was in de neus van de romp geplaatst. In de stuurboordvleugel was een gondel geplaatst waarin zich de cockpit bevond. De cockpit was van een druppelkap voorzien. De romp was kort en dik uitgevoerd.

De bewapening bestond uit twee 20mm-MG151/20-kanonnen die onder de cockpit waren aangebracht. Onder de gondel kon 500 kg aan bommen worden opgehangen.

Er was een staartwiel landingsgestel geplaatst. Het hoofdlandingsgestel werd buitenwaarts in de vleugeltippen die hiervoor een speciale vorm hadden gekregen.
Spanwijdte: 10,39 m.
Lengte: 8,43 m.

Bommenwerper
Projectvliegtuig in de Tweede Wereldoorlog
P.179

redpajama_set_name: RedPajamaWikipedia


text:
Fighting Fantasy Legends Is A Card Driven Rpg For Mobile And Pc Based
Fighting Fantasy Legends is a card-driven RPG for mobile and PC based on the legendary gamebooks
A No Brainer? CMON Launch Marvel Zombies!
Find the D&D Monsters You Didn't Know You Needed in Mordenkainen Presents: Monsters of the Multiverse
What's inside Issue 466 of Miniature Wargames
Refighting History Review
ZineQuest Statement from Kickstarter
Panzer Lehr Review
Fighting Fantasy Legends
Nomad Games' digital adaptation based on City of Thieves, The Warlock of Firetop Mountain and Citadel of Chaos stories
After Nomad Games released a cryptic six-second teaser for its latest digital tabletop adaptation Fighting Fantasy Legends late last month, the Talisman studio has now taken the wraps off the project.
Legends will take the choose-your-own-adventure format of Ian Livingstone and Steve Jackson's classic series of gamebooks and transform them into a card-driven RPG for iOS, Android and PC through Steam.
Based on three of the best-known Fighting Fantasy stories – City of Thieves, The Warlock of Firetop Mountain (which was previously turned into a board game) and Citadel of Chaos – the game lets players explore the world of Allansia, adding cards to their deck and improving their dice rolls for events such as combat and skills tests.
There will be cards themed around each environment – but no word on whether you'll be able to buy extra cards or adventures via microtransactions or expansions just yet.
Fighting Fantasy Legends will be out this summer, marking the 35th anniversary of the books' debut. Livingstone is also currently working on a new entry in the series that is planned for release in August.
MWG Magazine!
Issue #466 of Miniature Wargames is now on sale - The magazine for all wargamers!


text:
The Turning Dance of the Bee
A dialogue on musical concepts, motifs and form in contemporary classical music between composer and performer.
Syzygy Ensemble has been pioneering the vitality and performance of contemporary classical music for 10 years. In Turning Circles this September, Syzygy performs Liza Lim's composition The Turning Dance of the Bee, an exploration of motifs from the natural world, Australiana, and its influence on dance as a classical music form.
Syzygy's cellist Campbell Banks spoke with Liza about her composition and where it all began - with her deep fascination with bees.
Campbell Banks (CB): We've been enjoying the challenge of putting your composition The Turning Dance of the Bee together in rehearsal! The title struck me when I first heard it, as my ignorance of bee revelry left me struggling to join the concepts of 'dance' and 'bees' into a coherent image in my mind. What is the meaning behind the title and do bees really dance?
Liza Lim (LL): We perhaps like to think that only humans have art and aesthetics, but I think we take our cue from the natural world. Art is an expression of deep patterns of being whether you're a human or a bee.
Researchers say that honeybees dance as a communication system to share knowledge about sources of flowers rich in nectar and pollen. They perform a 'waggle' dance that traces circles or a looping figure eight, angling their movements against the direction of the sun as navigational information for fellow bees.
I'd like to think that it's not just for practical reasons but that there's a poetic and ecstatic dimension to the dance.
CB: How did you first encounter the 'waggle' dance and what led you to turn this inspiration into a composition?
LL: Bees are very much at the forefront of conversations about the extinction crisis that we're now in – they're in decline all over the world which is incredibly serious because without these pollinators we're done for.
I've long been interested in the incredible culture of bees, their social structures and the kind of soul wisdom they bring.
Blue Banded Bee
I'm also a devotee of inner urban gardening. I have a tiny garden in my front yard in South Yarra comprising two long planter boxes next to the driveway and I love spending time out there poking amongst at the veggies and observing the wildlife. I'd love to keep bees but don't have space so I plant things they can visit. The restaurant down the street has hives on its roof as part of the popular urban bee-keeping movement which has spread around the world (you can check it out here).
Australia has some of the most strikingly beautiful native bees in the world and the best days are when I see Australian native blue banded bees in the garden. (Australia also has the cutest bee – check out the golden, fluffy, chubby 'teddy bear' bee)
CB: Your composition has two movements, Solar and Lunar. Given the integral role of the sun in bee navigation, how do we interpret these movement titles? Some species of bees navigate by moonlight, so can the audience expect to hear a change in the rhythmical impulse in the Lunar movement?
LL: Yes, Solar and Lunar are different rhythms, different qualities of time – one is more active and the other more languid and contemplative.
CB: There are many wonderful passages throughout the work but two have sparked Syzygy's curiosity. The end of the first movement sees the clarinet and piano settle into a genuine groove, with the slap-tongue of the clarinet propelling the movement to a close (our clarinettist Robin Henry has dedicated much blood and a calloused tongue to this passage, to brilliant effect). It seems significant that a clear pulse emerges and dominates at the end of the movement. What is the meaning of this passage?
LL: The first part begins with 'song' in the ornamented violin line and ends with 'dance' with that bass clarinet/piano groove!
CB: We are looking forward to performing this in the brilliant acoustic of the Primrose Potter Salon where we'll be opening the concert with the sound of stone on concrete tile! Is there anything else you'd like to tell the audience (or us) before the performance?
LL: Support the bees! Support your local beekeeper by buying their honey. It might be more expensive than cheap supermarket honey (which can be doctored by mixing low grade honey with corn syrup). Natural organic honey is a beautiful thing with wonderful anti-bacterial properties and is the joy of the earth in edible form.
Syzygy Ensemble plays Liza Lim's The Turning Dance of the Bee, plus works by Tansy Davies, Sean Shepherd and Andrew Byrne in Turning Circles on 26 September.
5 Reasons Why You Should Know Margaret Leng Tan - 2988
The Queen of the Toy Piano
ArticlePlaylist
FIVE REASONS WHY YOU SHOULD KNOW COMPOSER LOUIS ANDRIESSEN - 2688
If you haven't heard of Louis Andriessen, it's time you get acquainted.
anon. on Greenbaum, Buc & Schynder - 2610
anon. deep dives on the compositions featured in their upcoming show


text:
Trump signs short-term spending bill just before shutdown deadline
The measure funds federal programs through Dec. 20. Congress must pass a new measure by then to avoid a shutdown.
By Erica WernerThe Washington Post
WASHINGTON — President Trump signed a short-term spending bill Thursday to keep the government open through late December, staving off a shutdown that would have begun at midnight.
Trump's signature on the stop-gap spending bill came following Senate passage of the legislation on a bipartisan 74-20 vote. The House passed it earlier in the week in the midst of public impeachment hearings.
Without the legislation, government funding would have expired Thursday at midnight, forcing multiple agencies to begin to close down operations and send federal workers home.
The bill extends government funding through Dec. 20, setting up a fight over money for Trump's border wall that could happen around the same time the House is voting on articles of impeachment against the president.
It is the second stopgap spending bill Congress has been forced to pass to keep the lights on in government for the 2020 budget year that began Oct. 1.
Congress is supposed to pass 12 annual spending bills to fund the military and federal agencies, but lawmakers have yet to agree on a single one of them for 2020. Instead the spending process has again sunk into dysfunction, even though Congress and the White House passed a broad budget deal over the summer that extended the debt limit past the 2020 election and set top-line spending levels for the military and domestic agencies.
That deal was supposed to make it easier for Congress' spending committees to write their bills. But negotiations quickly descended into partisan bickering over the terms of the deal. Looming over it all is Trump's demand for billions for his border wall, the same issue that caused a record-long 35-day government shutdown last winter. Aides have studied the possibility of diverting the money from existing funds if Congress does not approve more, a step the administration took earlier this year – over bipartisan opposition – after Trump declared a national emergency at the border.
Trump and Senate Republicans want $5 billion for the wall, but House Democrats included no such money at all in the spending bills they passed. It remains unclear where a compromise might lie. By extending funding through Dec. 20, lawmakers hope to give themselves time to come up with a deal on that issue and others that would allow them to pass full-year bills to fund the government for the rest of the budget year that ends Sept. 30, 2020.
Hopes for such a deal look highly uncertain, but the alternative is to extend funding at current levels through the remainder of 2020, which would cause the Pentagon and domestic agencies to miss out on billions of dollars in budget increases. That's an outcome lawmakers in both parties would like to avoid. It's also possible that Congress could end up cobbling together a package of some full-year spending bills while extending other agency budgets at current levels.
"We could get it all done if we work together," said Senate Appropriations Chairman Richard Shelby, R-Ala. "If we don't work together, if we continue to slow-walk, we'll be where we are today."
Senate Minority Leader Charles Schumer, D-N.Y. said he was optimistic passage of the short-term "continuing resolution" Thursday would be "something Congress can build from, a sign that appropriators from both sides of the aisle are ready to work together to settle government funding by the end of the calendar year."
In addition to the funding extension, the spending legislation includes a grab-bag of other provisions, including a 3.1 percent military pay raise and money to conduct the Census. It also extends some expiring provisions of the USA Patriot Act.
Secret Service spent quarter-million dollars at Trump's properties in first five months
A bittersweet birthday break-up with sugar
To get past 'Quitters' Day,' check in with your food and drink resolutions


text:
Mark Hamill Provides Grim Outlook for Star Wars: "Is There a Possibility of Star Wars Fatigue? Yeah"
Star Wars actor Mark Hamill, who has played Luke Skywalker in 5 of the 11 Star Wars films provided a grim outlook for the franchise.
Hamill was asked about the idea of Star Wars fatigue on The Hollywood Reporter's "Awards Chatter" podcast. He was specifically asked if Star Wars fatigue exists. Hamill simply replied, "Yes."
When pressed on the question he would elaborate, "I'm not gonna tell them how to run their business, but is there a possibility of 'Star Wars fatigue'? Yeah, I think there is. I've experienced it, to a certain degree. But they never listen to my ideas anyway, so who needs 'em?"
However, before discussing Star Wars fatigue, Hamill noted the last time he had actually seen the Star Wars films was 21 years ago.
"The last time I saw them was 21 years ago when they were rereleased as special editions…We saw each one once in 1998."
As for the possibility of doing more work with Star Wars, Hamill was open to the idea saying, "Well, again, make me an offer."
While Hamill indicates that executives don't listen to his advice, Disney CEO Bob Iger also alluded to the idea of Star Wars fatigue following the failure of Solo: A Star Wars Story.
Last September Iger admitted he made a mistake with the Star Wars franchise pointing out the closeness of the films was too much.
"I made the timing decision, and as I look back, I think the mistake that I made — I take the blame — was a little too much, too fast. You can expect some slowdown, but that doesn't mean we're not going to make films. J.J. [Abrams] is busy making [Episode] IX. We have creative entities, including [Game of Thrones creators David] Benioff and [D.B.] Weiss, who are developing sagas of their own, which we haven't been specific about. And we are just at the point where we're going to start making decisions about what comes next after J.J.'s. But I think we're going to be a little bit more careful about volume and timing. And the buck stops here on that."
As I argued last year when Iger made these comments, there shouldn't be Star Wars fatigue if you are making quality content. In fact, Disney's own companies including Marvel Studios and Pixar were putting out more movies than Star Wars and were still seeing wild success at the box office.
The issue isn't about Star Wars fatigue due to volume. People won't get worn out by too much Star Wars content. I mean there's been plenty of Star Wars content created across multiple mediums and people are still eating it up.
The issue with Star Wars fatigue at the box office is an issue with respecting the source material and creating good, entertaining Star Wars content. Star Wars failed at that with Rian Johnson's The Last Jedi, and it shattered a lot of the trust the Star Wars brand had with consumers in Disney.
In the podcast, Hamill would also choose his favorite Star Wars film. Here's a hint, it's not The Last Jedi.
"I guess I'd probably have to go with Empire, only because it was so unexpected to have the protagonist be so soundly defeated, losing the hand and the dad Vader, all of it was pretty unexpected. And it was so cerebral: Yoda is such an important addition to the mythology and I thought it was so clever of George, the concept of the Force, so that you could talk about religion and spirituality without making people uncomfortable. So for that alone."
What do you make of Hamill's comments? Do you think there is Star Wars fatigue?
Mark HamillStar Wars
Founder and Editor-in-Chief
John is the Editor-in-Chief here at Bounding Into Comics. He is a massive Washington Capitals fan, lover of history, and likes to dabble in economics and philosophy.
Ryan Pearson
The Walt Disney Company's Grooming Agenda Continues, Star Wars Celebration To Feature Panel About Drag Shows


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Justia Patents With Reference Voltage CircuitryUS Patent for Waveform shaping in power tool powered by alternating-current power supply Patent (Patent # 11,173,584)
Waveform shaping in power tool powered by alternating-current power supply
Jun 27, 2019 - Black & Decker Inc.
A power tool is provided including a brushless DC (BLDC) motor, a rectifier that receives an alternative current from a power supply and outputs a rectified signal supplied to a DC power bus, and an inverter circuit having motor switches connected electrically between the DC power bus and the motor. A control module controls a switching operation of the power switches to regulate supply power from the power supply to the motor. The control module controls the switching operation so as to, within a half cycle of the AC power supply voltage waveform, increase current draw from the power supply from a first threshold at or after a first zero-crossing of the half cycle up to a second threshold, and reduce current draw from the power supply from the second threshold up to a third threshold at or prior to a second zero-crossing of the half cycle.
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RELATED APPLICATION
This patent application is a continuation of co-pending U.S. patent application Ser. No. 15/481,838 filed Apr. 7, 2017, which is incorporated herein by reference in its entirety.
This disclosure relates to control schemes for driving a brushless DC motor in a power tool, and in particular to driving a brushless DC motor from an AC power supply.
Power tools may be of different types depending on the type of output provided by the power tool. For example, a power tool may be a drill, hammer, grinder, impact wrench, circular saw, reciprocating saw, and so on. Some power tools may be powered by an alternating current (AC) power source or a direct current (DC) power source such as a battery pack. In power tools using a brushless DC (BLDC) motor, a series of electronic switches are used to electronically energize motor windings sequentially in order to drive the motor rotor. Using these switches, the speed and rotational direction of the rotor can be controlled.
In power tools having brushless DC motors powered by an Alternating Current (AC) power source, a rectifier circuit is often employed to convert negative portions of the current waveform to positive current needed to drive the motor. Using motor control schemes conventionally used with DC power sources, which have a nearly-linear voltage waveform, encounters challenges when used on power tools powered by AC power sources. These challenges relate to the non-linear voltage waveform of the AC power supply and to certain inherent electrical characteristics of the motor that affect current draw from the power supply, which contribute to reduced power factor and motor efficiency. What is needed is a motor control scheme that addresses these challenges.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of this disclosure in any way.
FIG. 1 depicts an exemplary perspective view of a power tool, according to an embodiment;
FIG. 2 depicts an exemplary exploded view of a brushless DC motor, according to an embodiment;
FIG. 3 depicts an exemplary block diagram for a motor control system, according to an embodiment;
FIG. 4 depicts an exemplary switching arrangement circuit configured as a three-phase inverter bridge circuit, according to an embodiment;
FIG. 5 depicts an exemplary waveform diagram of a pulse-width modulation (PWM) drive sequence of the three-phase inventor bridge circuit of FIG. 4 within a full 360 degree conduction cycle, according to an embodiment;
FIGS. 6A-6C depict bus voltage and AC line current waveform diagrams for an exemplary small value DC bus capacitor, an exemplary medium value DC bus capacitor, and an exemplary large value DC bus capacitor, respectively, according to an exemplary embodiment;
FIG. 7 depicts an exemplary waveform diagram showing the DC bus voltage relative to the motor back-EMF (Electromagnetic Force) voltage, according to an embodiment;
FIG. 8 depicts an exemplary voltage waveform diagram corresponding to an improved PWM drive control scheme, according to an embodiment of the invention;
FIG. 9 depicts an exemplary combined voltage-time and current-time waveform diagram depicting the AC input line voltage, the DC bus voltage, the AC input line current, when driving the power tool motor using a conventional PWM switching scheme, according to an embodiment;
FIG. 10 depicts an exemplary voltage waveform diagram showing an improved PWM drive control scheme, according to an alternative and/or additional embodiment of the invention;
FIG. 11 depicts an exemplary combined voltage-time and current-time waveform diagram depicting the AC input line voltage, the DC bus voltage, the AC input line current, when driving the power tool motor using the improved PWM switching scheme, according to an embodiment; and
FIG. 12 depicts an exemplary waveform diagram of the drive sequence of the three-phase inventor bridge circuit at a 150 conduction band, according to an embodiment.
According to an embodiment of the invention, a power tool is provided including a housing, and a brushless DC (BLDC) motor arranged within the housing and having a stator and a rotor rotatably disposed within the stator. In an embodiment, the power tool further includes a rectifier configured to receive an alternative current from an alternating current (AC) power supply and output a rectified signal supplied to a DC power bus, and an inverter circuit having a motor switches connected electrically between the DC power bus and the motor and operable to deliver electric power from the DC power bus to the motor. In an embodiment, the power tool further includes a control module configured to control a switching operation of the power switches to regulate supply power from the power supply to the motor. In an embodiment, the control module is configured to halt or reduce the switching operation of the power switches between a first threshold prior to a zero-crossing of the AC power supply voltage waveform and a second threshold after the zero-crossing of the AC power supply voltage waveform.
In an embodiment, a back-electromagnetic force (back-EMF) voltage of the motor exceeds the voltage on the DC power bus within a region of the DC power bus voltage waveform between the first threshold and the second threshold, and the controller prevents or significantly reduces flow of current from the motor to the DC power bus, or braking of the motor, between the first threshold and the second threshold.
In an embodiment, the control module is configured to set a pulse-width modulated (PWM) duty cycle of the inverter circuit in accordance to a target rotational speed of the motor.
In an embodiment, the control module is configured to reduce the PWM duty cycle to zero between the first threshold and the second threshold. Alternatively, the control module may reduce the PWM duty cycle to a low value (e.g., up to 30% of the set PWM duty cycle) between the first threshold and the second threshold.
In an embodiment, the control module is configured to detect an actual rotational speed of the motor and set the PWM duty cycle as a function of the difference between the target rotational speed and the actual rotational speed.
In an embodiment, a capacitor is arranged across the DC power bus. In an embodiment, capacitor has a capacitance value that is sufficiently small so that the voltage of the back-electromagnetic force (back-EMF) of the motor exceeds the voltage on the DC power bus within a region of the DC power bus voltage waveform between the first threshold and the second threshold.
In an embodiment, the first and second thresholds correspond to voltage values of at least one of the DC power bus or the AC power supply.
In an embodiment, the first threshold is on the rising portion of the DC bus voltage and the second threshold is on the falling portion of the DC bus voltage. In an embodiment, the first threshold corresponds to a smaller voltage value on the DC bus voltage waveform than the second threshold.
In an embodiment, the first and second thresholds correspond to timing values between and after a zero-crossing of the AC power supply.
In an embodiment, the first and second thresholds are predetermined values.
In an embodiment, the controller is configured to calculate or monitor at least one of a back-EMF voltage of the motor or the rotational speed of the motor and set the first and second thresholds as a function of the back-EMF voltage or the rotational speed of the motor.
According to another aspect/embodiment of the invention, a power tool is provided including a housing and a brushless DC (BLDC) motor arranged within the housing and having a stator and a rotor rotatably disposed within the stator. In an embodiment, the power tool further includes a rectifier configured to receive an alternative current from an alternating current (AC) power supply and output a rectified signal supplied to a DC power bus, and an inverter circuit having motor switches connected electrically between the DC power bus and the motor and operable to deliver electric power from the DC power bus to the motor. In an embodiment, the power tool further includes a control module configured to control a switching operation of the power switches to regulate supply power from the power supply to the motor. In an embodiment, the control module is configured to control the switching operation of the power switches so as to, within a half cycle of the AC power supply voltage waveform, increase current draw from the power supply from a first threshold at or after a first zero-crossing of the half cycle up to a second threshold, and reduce current draw from the power supply from the second threshold up to a third threshold at or prior to a second zero-crossing of the half cycle.
In an embodiment, the second threshold is between the first threshold and a peak of the half cycle.
In an embodiment, the control module is configured to set the PWM duty cycle to zero between the first zero-crossing of the half cycle and the first threshold, and between the third threshold and the second zero-crossing of the half cycle.
In an embodiment, the control module is configured to scale the PWM duty cycle to a higher value between the first and second thresholds, and to a lower value between the second and third thresholds.
In an embodiment, the control module is configured to scale a conduction band corresponding to phases of the motor to a higher value between the first and second thresholds, and to a lower value between the second and third thresholds.
The following description illustrates the claimed invention by way of example and not by way of limitation. The description clearly enables one skilled in the art to make and use the disclosure, describes several embodiments, adaptations, variations, alternatives, and uses of the disclosure, including what is presently believed to be the best mode of carrying out the claimed invention. Additionally, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
FIG. 1 depicts an example power tool 10. In this example embodiment, the power tool 10 comprises a housing 12 having an elongated shape. A user can grasp the power tool 10 by placing the palm of the user's hand over and around the housing 12. An output member 18 is positioned at one end 12-1 of the housing 12 and comprises a gearset 20 that drives a rotating disk 22. In this example embodiment, the rotating disk 22 comprises a grinder disk.
The rotating disk 22 may be removed and replaced with a new rotating disk. For example, a user of the power tool 10 may replace the existing rotating disk 22 with a new rotating disk after the existing rotating disk 22 wears out. An adjustable guard 24 may cover at least a portion of the rotating disk 22 to obstruct sparks and debris generated during operation of the power tool 10.
The housing 12 may enclose an electric motor 28 (described below with reference to FIG. 2) near the end 12-1 of the housing. The housing 12 may further include a first portion 14 and a second portion 16. The first portion 14 and the second portion 16 may be secured together with screws 26, and enclose electronic circuit components that drive the motor 28. A power cord 30 is connectable to an AC power supply and is positioned at an opposite end 12-2 of the housing 12. The power cord 30 provides power to the electric motor 28 and the electronic circuit components of the power tool 10. The power cord 30 may be coupled to any suitable AC power supply compatible with the operating range of the power tool motor, for example, 120V AC mains in the US, or 230V AC mains in Europe. The power supply may also be a power generator.
The housing 12 may further support a power on/off switch 32 and a spindle lock switch 34. Operating the power on/off switch 32 in ON and OFF positions turns the electric motor 28 ON or OFF, respectively. Pressing and holding the spindle lock switch 34 enables the user to change the rotating disk 22. A plurality of narrow slot openings 36 of the housing 12 and/or the first 14 and second 16 portions allow for venting of the electric motor 28 and the electronic circuit components. The one end 12-1 of the housing 12 also includes a threaded opening 38 for selectively attaching a side-handle (not shown) to enable two-handed operation.
While the present description is provided with reference to a grinder, it is readily understood that the broader aspects of the present disclosure are applicable to other types of power tools, including but not limited to sander, drill, impact driver, tapper, fastener driver, and saw. For example, the power tool 10 may include a chuck that is configured to receive a drill bit or a screw driver bit, thereby allowing the power tool 10 to be used as a power drill or a power screw driver. In another example embodiment, the output member 18 may be removed and replaced with another output member that may be more suitable for a drill, a screw driver, or any other power tool.
FIG. 2 depicts a perspective exploded view of the motor 28, according to an embodiment. In this embodiment, motor 28 is a three-phase brushless DC (BLDC) motor having a can or motor housing 29 sized to receive a stator assembly 70 and a rotor assembly 72.
In an embodiment, rotor assembly 72 includes a rotor shaft 44, a rotor lamination stack 76 mounted on and rotatably attached to the rotor shaft 44, a rear bearing 78 arranged to axially secure the rotor shaft 44 to the motor housing 29, a sense magnet ring 74 attached to a distal end of the rotor shaft 44, and fan 37 also mounted on and rotatably attached to the rotor shaft 44. In various implementations, the rotor lamination stack 76 can include a series of flat laminations attached together via, for example, an interlock mechanical, an adhesive, an overmold, etc., that house or hold two or more permanent magnets (PMs) therein. The permanent magnets may be surface mounted on the outer surface of the lamination stack 76 or housed therein. The permanent magnets may be, for example, a set of four PMs that magnetically engage with the stator assembly 70 during operation. Adjacent PMs have opposite polarities such that the four PMs have, for example, an N-S-N-S polar arrangement. The rotor shaft 44 is securely fixed to the rotor lamination stack 76. Rear bearing 78 provide longitudinal support for the rotor 74 in a bearing pocket (not shown) that secures the motor to the tool housing 12 or a motor housing (not shown).
In an embodiment, fan 37 of the rotor assembly 72 includes a back plate 60 having a first side 62 facing the motor case 16 and a second side 64. A plurality of blades 66 extend axially outwardly from first side 62 of the back plate 60. Blades 66 rotate with the rotor shaft 44 to generate an air flow. When motor 28 is fully assembled, fan 37 is located at or outside an open end of the motor 28.
In an embodiment, stator assembly 70 includes a generally cylindrical lamination stack 80 having center bore configured to receive the rotor assembly 72. Lamination stack 80 further includes a plurality of stator teeth on which stator coil windings 86 are wound. The stator coil windings 86 are wound in three phases and coupled through a controllable switching arrangement circuit to a power supply, as described below. Energizing the respective phases of the stator coil windings 86 causes the rotor assembly 72 to rotate inside the stator assembly 70.
FIG. 3 depicts a schematic that illustrates an example of a motor control system 100 that may be employed by the power tool 10. The motor control system 100 is comprised generally of a controller 102, a switching arrangement (also referred to as an inverter circuit) 104, a driver circuit 106, a rectifier 108, and a DC bus capacitor 110, and a power supply regulator 112. The motor control system 100 may further include position sensors 114, such as Hall Effect sensors that are configured to detect rotational motion of the electric motor 28 and generate a signal indicative of the rotational motion. The signal may have a periodic waveform whose magnitude may vary in accordance with the rotational position of the electric motor 28. It should be noted, that other types of positional sensors may be alternatively utilized and should not be limited to Hall-effect sensors.
An AC power supply 116 delivers an alternating current to the rectifier 108 through, for example, the power cord 30. The rectifier 108 converts the alternating current into a direct current that is outputted to a DC bus 115 (i.e., power line/bus). The output of the rectifier 108 may be a pulsating DC signal and not a pure DC signal.
The DC bus capacitor 110 is electrically connected in parallel with the rectifier 108 on the DC bus line 115. The switching arrangement 104 is coupled to DC bus 115 line and receives rectified voltage from the rectifier 108 and the DC bus capacitor 110. The switching arrangement 104 includes a plurality of motor switches that, when switched on, deliver the DC current to the electric motor 28. The motor switches may be IGBTs or FETs. The switching arrangement 104 may be further defined as a three-phase inverter bridge although other arrangements are contemplated by this disclosure.
The driver circuit 106 interfaces with the motor switches of switching arrangement 104. The driver circuit 106 controls the state of the motor switches. In the example embodiment, the driver circuit 106 is shown as being separate from the switching arrangement 104. Alternatively, the driver circuit 106 and the switching arrangement 104 may be a single integrated circuit which may be commercially available from various manufactures. For example, the switching arrangement 104 and the driver circuit 106 may be a part of an integrated power module. In an embodiment, the switching arrangement 104 includes a series of high-side and low-side semiconductor switches configured as a three-phase inverter circuit as described below.
The controller 102 interfaces with the driver circuit 106 and may generate PWM signals to control the electric motor 28. In this embodiment, the controller 102 receives power from the power supply regulator 112. In an alternate embodiment, the controller 102 may receive power directly from the rectifier 108.
The power supply regulator 112 is electrically connected in parallel with the rectifier 108 and operates to power the driver circuit 106 via the power on/off switch 32. The power on/off switch 32 is positioned between the power supply regulator 112 and the driver circuit 106.
When the power on/off switch 32 is switched to the ON-position, the driver circuit 106 receives power from the power supply regulator 112. When the driver circuit 106 receives power, the driver circuit 106 is able to control the state of the motor switches and the electric motor 28 is on.
Conversely, when the power on/off switch 32 is switched to the OFF-position, the driver circuit 106 does not receive power from the power supply regulator 112. When the driver circuit 106 does not receive power, the driver circuit 106 is not able to control the state of the motor switches and the electric motor 28 is off.
In the illustrated example, the power on/off switch 32 is electrically connected between the power supply regulator 112 and the driver circuit 106. Thus, the current being drawn by the electric motor 28 does not pass through the power on/off switch 32. The current passing through the power on/off switch 32 is the current being drawn by the driver circuit 106 and the current being drawn by the driver circuit 106 is lower than the current being drawn by the electric motor 28. It must be understood, however, that in an alternative embodiment, the on/off switch 32 may be a current-carrying switch disposed, for example, on the DC bus line 115 between the rectifier 108 and the switching arrangement 104.
In an embodiment, the DC bus capacitor 110 may be a link capacitor having a relatively small capacitance and does not significantly smoothen the full-wave rectified AC voltage, but rather removes the high frequency noise from the bus voltage.
FIG. 4 depicts an exemplary switching arrangement circuit 104 configured as a three-phase inverter bridge circuit, according to an embodiment. As shown herein, the three-phase inverter bridge circuit includes three high-side power switches and three low-side power switches 202. The power switches 202 in this embodiment are Insulated-Gate Bipolar Transistors (IGBTs), although it is understood that other types of power switches such as Field-Effect Transistors (FETs) may alternatively be utilized. In an embodiment, for high power/high voltage power tool applications, such as those driven by an AC mains power supply, IGBTs may be more suitable. The gates of the high-side switches driven via drive signals UH, VH, and WH, and the gates of the low-side switches are driven via drive signals UL, VL, and WL. In an embodiment, the collectors of the low-side switches are coupled to the emitters of the high-side switches to output power signals PU, PV, and PW for driving the respective phases of the motor windings 86.
FIG. 5 depicts an exemplary waveform diagram of a pulse-width modulation (PWM) drive sequence of the three-phase inventor bridge circuit of FIG. 4 within a full 360 degree conduction cycle. As shown in this figure, within a full 360° cycle, each of the drive signals associated with the high-side and low-side power switches is activated during a 120° conduction band ("CB"). In this manner, each associated phase of the BLDC 202 motor is energized within a 120° CB by a pulse-width modulated voltage waveform that is controlled by the control unit 208 as a function of the desired motor 28 rotational speed. For each phase, the high-side switch is pulse-width modulated by the control unit 208 within a 120° CB. During the CB of the high-side switch, the corresponding low-side switch is kept low, but one of the other low-side switches is kept high to provide a current path between the power supply and the motor windings. The control unit 208 controls the amount of voltage provided to the motor, and thus the speed of the motor, via PWM control of the high-side switches.
It is noted that the controller 102 may set the PWM duty cycle based on a target motor speed as determined from an input unit (e.g., power tool trigger switch or speed dial). Additionally and/or alternatively, the controller 102 may set the PWM duty cycle via a close-loop speed control technique, where the controller 102 adjusts the PWM duty cycle in order to maintain the target motor speed as load is applied to the power tool. In an embodiment, the controller 102 may monitor and/or calculate the actual rotational speed of the motor, compare the actual speed to the target motor speed, and adjust the set PWM duty cycle as a function of the difference between the target speed and the actual speed until the actual speed matches the target motor speed.
FIGS. 6A-6B highlights the advantages of using a relatively small DC bus capacitor 110 in the power tool 10. FIG. 6A, in an embodiment, depicts the voltage waveform using a relatively large DC bus capacitor 110 (e.g., approximately 400 to 1000 μF) and the associated current waveform. FIG. 6B depicts the voltage waveform using a relatively mid-sized DC bus capacitor 110 (e.g., approximately 50 to 200 μF) and the associated current waveform. FIG. 6C depicts the voltage waveform using a very small DC bus capacitor 110 (e.g., approximately 10 to 30 μF) and the associated current waveform. It is noted that these DC bus capacitor values depend on many factors, most notably the power tool power output requirement. It is noted that exemplary capacitor values provided herein are implemented and tested in conjunction with a circuit as shown in FIG. 2 with max power out of 1.5 to 2 kW.
As shown in FIG. 6A, when using a large DC bus capacitor 110, the current is drawn from the DC bus capacitor 110 for a large portion of each cycle during the capacitor discharge. Thus, current drawn from the AC power supply during each cycle occurs within a small window, which creates a significant current spike. To obtain a constant RMS current of, for example, 10A from the AC power supply, the current level within the small window increases substantially, which creates the current spikes.
The current spikes in this arrangement are undesirable for two reasons. First, the power factor of the tool becomes low, and the harmonic content of the AC current becomes high. Secondly, for a given amount of energy transferred from the AC source to the tool, the peak value of the current will be high. The practical result of this arrangement is that an unnecessarily large AC circuit breaker is required to handle the current spikes for a given amount of work.
By comparison, as shown in FIG. 6B, when using a mid-sized, the current is drawn from AC power supply within each cycle occurs within a broader time window, which provides a lower harmonic content and higher power factor. Similarly, as shown in FIG. 6C, when using an even smaller capacitor, the current drawn from the capacitor is very small (almost negligible) within each cycle. Thus, the current drawn from the AC power supply is even broader within each cycle. This provides an even lower harmonic context and a much higher power factor in comparison to FIG. 6A.
Additionally, although small DC bus capacitors provide a lower average voltage to the motor control system, it is indeed possible to obtain a higher power output from the AC power supply. In particular, the smaller capacitors enable more power to be drawn from the AC power supply with a lower harmonic context and higher power factor.
For more details on the benefits and advantages of using a small DC bus capacitor in an AC powered or hybrid AC/DC powered power tool system, reference is made to U.S. patent application Ser. No. 14/715,258 filed May 18, 2015, which is incorporated herein by reference in its entirety.
An aspect of the invention is described herein with reference to the voltage waveform diagram of FIGS. 7 and 8, according to an embodiment.
According to an embodiment, as shown in FIG. 7, when employing a relatively small-value DC bus capacitor, the value of the motor back-EMF voltage may exceed the voltage of the DC bus line in regions near the zero-crossings of the input AC voltage waveform. As understood by persons skilled in the art, the motor back-EMF (Electromagnetic Force) voltage is the voltage induced in the stator windings by the rotation of the rotor within the stator. It must be understood that while the average back-EMF voltage of the motor is illustrated in FIG. 4 as a straight line for illustration purposes, the back-EMF voltage may vary based on many factors, including but not limited to, the load on the motor, the motor speed, etc.
In FIG. 7, the region designated as 'A' corresponds to the area around the zero-crossings of the input AC voltage waveform where the DC bus voltage becomes smaller than the back-EMF voltage of the motor. The DC bus voltage within this region can reach significantly low levels, even approaching zero, depending on the size of the DC bus capacitor. The continuous switching operation of the three-phase inverter circuit 104 within region 'A' of the voltage waveform fails to apply electrical energy from the DC bus line to the motor. Rather, the continuous switching of the inverter circuit 104 within this region may allow the back-EMF current of the motor to flow into the DC bus in reverse, thus applying a braking force to the motor to slow down the motor rotation.
In order to alleviate this problem near the zero-crossings of the AC line voltage waveform, according to an embodiment of the invention, the controller 102 is configured to execute an improved PWM switching technique wherein the controller 102 halts or significantly reduces the PWM switching operation of the inverter circuit 104 at region 'A' the voltage waveform. For example, within region 'A', the controller 102 may set the PWM duty cycle to zero, or to a low duty cycle value that outputs very little power to the motor 28. FIG. 8 depicts an exemplary voltage waveform diagram showing improved PWM drive control scheme that accomplishes this objective, according to an embodiment of the invention.
In this embodiment, the controller 102 is configured to start and stop PWM switching of the inverter circuit 104 based on threshold values T1 and T2. In an embodiment, threshold T1 may be designated on a rising portion of the DC bus voltage following a zero-crossing of the AC input line voltage, and threshold T2 may be designated on a falling portion of the DC bus voltage prior to a subsequent zero-crossing of the AC input line voltage.
It is noted that instead of fully stopping the PWM switching at T2, reducing the set PWM duty cycle to a significantly low value (e.g., duty cycle of up to 30%, or to a value that is up to 30% of the set duty cycle) that does not result in significant motor braking is within the scope of this disclosure.
In an embodiment, threshold values T1 and T2 may be voltage threshold values. In an embodiment, the controller 102 may monitor the DC bus voltage and start and stop the PWM switching operation of the inverter circuit 104 when the DC bus voltage is between threshold voltage values T1 and T2. Alternatively, controller 102 may monitor the AC input line voltage and start and stop the PWM switching operation of the inverter circuit 104 when the absolute value of the AC input line voltage is between threshold voltage values T1 and T2.
In an embodiment, threshold values T1 and T2 may alternatively be timing threshold values. In an embodiment, may determine the zero-crossings (or expected zero-crossings) of the AC line voltage and set the T1 and T2 threshold values accordingly. In an embodiment, the controller 102 may start and stop the PWM switching operation of the inverter circuit 104 between timing threshold values T1 and T2.
In an embodiment, region 'B' of the DC bus voltage between threshold values T2 and T1 may alight with or encompass region 'A'. In other words, threshold values T1 and T2 may be determined based on where the DC bus voltage waveform intersects with the back-EMF voltage waveform, or threshold values T1 and T2 may be determined such that region 'B' is slightly smaller or boarder than region 'A'. The specific designation of T1 and T2 threshold values may depend on various motor design, power tool, and power supply characteristics and requirements.
In an embodiment, for the reasons described later in this disclosure, threshold values T1 and T2 may be set such that the DC bus voltage is greater at threshold T2 than it is at threshold T1. In other words, T1 is closer to its preceding AC line voltage zero-crossing than T2 is to its subsequent AC line voltage zero-crossing.
In an embodiment, values of T1 and T2 may be predetermined and preprogrammed. Alternatively, the controller 102 may actively determine the threshold values T1 and T2 based on a variety of factors. For example, the controller 102 may monitor the back-EMF voltage of the motor and calculate the values of T1 and T2 accordingly. The controller 102 may also calculate the values of T1 and T2 based on the rotational speed of the motor, which may be correlated to the load applied on the power tool. In variable speed tools, the controller 102 may set the values of T1 and T2 based on a desired speed of the motor set in accordance with a variable speed input (e.g., a trigger or a speed dial).
According to an embodiment, as shown in the voltage waveform diagram of FIG. 8, the controller 102 performs a PWM switching operation on the inverter circuit 104 switches via control signals UH, VH, and WH, within region 'C' of the DC bus line between thresholds T1 and T2. Within region 'B' of the DC bus line, the controller 102 temporarily halts the PWM switching operation, or significantly reduces the PWM duty cycle, until the ensuing T1 threshold is reached within a subsequent AC line half cycle. In an embodiment, the controller 102 sets the PWM duty cycle to zero within region 'B'. Further, in an embodiment, the controller 102 may scale the PWM duty cycle outside of region 'B' to a level that outputs the power level required to rotate the motor at the target speed. This scheme prevents flow of current from the motor to the DC bus line at or near the zero-crossings of the AC line voltage.
An alternative and/or additional aspect of the invention is described herein with reference to FIGS. 9-11.
FIG. 9 depicts an exemplary combined voltage-time and current-time waveform diagram including the AC input line voltage, the DC bus voltage, and the AC input line current, when driving the power tool motor using a conventional PWM switching scheme. Due to the inherent inductive characteristics of the motor, the motor applies an inductive load to power supply, causing the AC input line current to lag slightly behind the AC input line voltage (and the DC bus voltage). As the AC input line current and voltage waveforms become out of phase, a smaller and imbalanced window becomes available for current to be drawn from the power supply within each AC line voltage half cycle. This results in large current spikes during the back half of the AC line voltage half cycles, as can be seen in the AC input line current waveform. These spikes adversely affect power factor and the harmonic content of the AC line current waveform.
According to an embodiment, an improved PWM drive control scheme is provided tailored to improving the shape of the AC line current waveform, and thus improving the power factor and harmonic content of the AC line current waveform, as described herein.
In an embodiment, as briefly described above, the controller 102 is configured to shift the AC current waveform such that it becomes more in phase with the AC input line voltage waveform. This is accomplished by setting thresholds T1 and T2 described above such that the DC bus voltage is smaller at threshold T1 in the rising portion of the DC bus voltage waveform following a zero-crossing of the AC input line voltage waveform, than it is at threshold T2 in the falling portion of the DC bus voltage waveform prior to a subsequent zero-crossing of the AC input line voltage waveform. In other words, T1 is closer to its preceding AC line voltage zero-crossing than T2 is to its subsequent AC line voltage zero-crossing. This allows for the motor to begin drawing current sooner within each half cycle, thus shifting the current waveform to the left so it is more in line with the AC input line voltage waveform.
In a further and/or alternative embodiment, the controller 102 is configured to scale and modify the PWM duty cycle such that the duty cycle has a higher value during a first portion of each AC line half cycle (approximately corresponding to the rising portion of the DC bus voltage) than during a second portion the AC line half cycle (approximately corresponding to the falling portion of the DC bus voltage). With this scheme, the controller 102 drives the motor with more power, and draws more current, during the first portion of each AC line half cycle than during the second portion. In an embodiment, the controller 102 scales the PWM duty cycle within the first and second portions within each AC line cycle consistent with the desired average power output for each AC line cycle. The added current draw during the front half of the AC line half cycles balances the AC line current waveform more evenly across the length of the AC line half cycle, providing a more sinusoidal AC current waveform with reduces peak current spikes. This scheme thus significantly improves power factor and the harmonic content of the AC line current waveform.
FIG. 10 depicts an exemplary voltage waveform diagram showing the improved PWM drive control scheme, according to an exemplary embodiment. In this embodiment, the AC waveform is separated to several discrete regions, each with its own scaling factor for power applied. In an exemplary embodiment, an additional voltage or timing threshold T3 is designated between thresholds values T1 and T2.
As described in previous embodiment, between threshold values T2 and T1 (i.e., region 'B' of the voltage waveform), the PWM duty cycle is set to zero.
In an embodiment, the controller 102 is further configured to apply scaling factors to the the PWM duty cycle outside of region 'B' such that the duty cycle is higher within region 'D' (between threshold values T1 and T3), than within region 'E' (between threshold values T3 and T2). The scaling of the PWM duty cycle provides more current draw in the beginning portion of each half cycle in order to balance the AC input line current waveform.
In an embodiment, threshold T3 may be designated near the peak of the DC bus voltage waveform half cycle between T1 and the peak, though it may also be designate between the peak and T2. In an embodiment, the controller 102 scales the PWM duty cycle within regions 'D' and 'E' such that the average power within the half cycle supply the desired power to the motor to produce the target rotational speed.
In an exemplary embodiment, the scaling factor applied by the controller 102 to the PWM duty cycle may be set to zero within region 'B', to a value greater than 1 (e.g., 1.1 to 1.3) within region 'D' between thresholds T1 and T3, and to a value less than 1 (e.g., 0.85 to 0.99) within region 'E' between thresholds T3 and T2. Thus, if for example, the average PWM duty cycle as calculated based on the target speed (in open loop), or based on the difference between the rotational speed and the target speed (in closed loop), is to be set to 50%, the controller 102 may set the PWM duty cycle to 0% within region 'B', to 60% within region 'D', and to 48% within region 'E'.
It is noted that while in FIG. 9 the AC line cycle is divided to three regions by way of example, the AC line cycle may be divided to more discrete regions by setting multiple threshold values between thresholds T1 and T2.
FIG. 11 depicts an exemplary combined voltage-time and current-time waveform diagram depicting the AC input line voltage, the DC bus voltage, the AC input line current, when driving the power tool motor according to the improved PWM switching scheme of the invention, according to an embodiment. As shown in this figure, as compared to FIG. 9, the AC input line current is more balanced, closer to a sinusoidal waveform, and more synchronized with the AC line voltage waveform, thus improving power factor and the harmonic content of the AC line current waveform.
The embodiments described above relates to PWM switching technique for controlling the motor speed. According to an alternative and/or additional embodiment of the invention, the same principles described above can be implemented by modifying and scaling the conduction band and/or advance angle of the motor, as described below.
Reference is now made PCT Application WO 2015/179318, filed May 18, 2015, which is incorporated herein by reference. This application describes a motor speed control technique using conduction band (CB) and/or advance angle (AA) control. As shown in FIG. 12, the conduction band (also referred to as the conduction angle) of each phase of the motor may be varied from the default 120 degrees to a greater or lesser value (in this example, 150 degrees) to control the amount of electrical energy provided to the motor, and thus the speed of the motor. As understood by those skilled in the art, advance angle (also referred to as the lead angle) is the shift in the phase of the conduction band to account for the motor phase current lagging behind the motor back-EMF voltage due to inherent inductances of the motor. Increasing and decreasing the advance angle may similarly be used to control the speed of the motor. Conduction band and advance angle control may be performed independently or in tandem.
Referring back to FIG. 10, according to an embodiment of the invention, the controller 102 may apply a scaling factor to the conduction band (instead of or in addition to the PWM duty cycle) to obtain a balanced AC line input current. In an exemplary embodiment, controller 102 may set the conduction band to be zero within region 'B'. This has the same effect as setting the PWM duty cycle to zero within this region. In addition, the controller 102 may apply a scaling factor the conduction band within region to 'D' and 'E'. The scaling factor may be a value greater than 1 within region 'D' less than 1 within region 'E'. Consequently, where the conduction band has a default value of 120 degrees, in an exemplary embodiment, the controller 102 may set the conduction band to a value in the range of 130-150 degrees within region 'D', and to a value in the range of 100-119 degrees within region 'E'. In an embodiment, the controller 102 may do this without scaling the PWM duty cycle, or in conjunction with scaling the PWM duty cycle.
Additionally and/or alternatively, according to an embodiment, the controller 102 may apply a scaling factor to the angle advance within regions 'D' and 'E' (instead of or in addition to the PWM duty cycle and/or the conduction band) to obtain a balanced AC line input current. In an embodiment, the scaling factor may be a value greater than 1 within region 'D' less than 1 within region 'E'. Consequently, where the angle advance has a default value of 30 degrees, in an exemplary embodiment, the controller 102 may set the angle advance to a value in the range of 35-50 degrees within region 'D', and to a value in the range of 10-28 degrees within region 'E'. In an embodiment, the controller 102 may do this without scaling the PWM duty cycle and the conduction band, or in conjunction with scaling the PWM duty cycle and/or the conduction band.
Some of the techniques described herein may be implemented by one or more computer programs executed by one or more processors, controllers and/or control units residing, for example on a power tool. The computer programs include processor-executable instructions that are stored on a non-transitory tangible computer readable medium. The computer programs may also include stored data. Non-limiting examples of the non-transitory tangible computer readable medium are nonvolatile memory, magnetic storage, and optical storage.
Some portions of the above description present the techniques described herein in terms of algorithms and symbolic representations of operations on information. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. These operations, while described functionally or logically, are understood to be implemented by computer programs. Furthermore, it has also proven convenient at times to refer to these arrangements of operations as modules or by functional names, without loss of generality.
Unless specifically stated otherwise as apparent from the above discussion, it is appreciated that throughout the description, discussions utilizing terms such as "processing" or "computing" or "calculating" or "determining" or "displaying" or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system memories or registers or other such information storage, transmission or display devices.
Certain aspects of the described techniques include process steps and instructions described herein in the form of an algorithm. It should be noted that the described process steps and instructions could be embodied in software, firmware or hardware, and when embodied in software, could be downloaded to reside on and be operated from different platforms used by real time network operating systems.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
a housing;
a brushless DC (BLDC) motor arranged within the housing, the motor including a stator having a plurality of phases and a rotor rotatably interacting with the stator;
a rectifier configured to receive an alternative current from an alternating current (AC) power supply and output a rectified signal supplied to a DC power bus;
an inverter circuit having a plurality of motor switches connected electrically between the DC power bus and the motor and operable to deliver electric power from the DC power bus to the motor; and
a control module configured to control a switching operation of the plurality of power switches to supply electric power from the power supply to the motor, the control module being configured to control a pulse-width modulation (PWM) duty cycle of the plurality of power switches within each AC half cycle of a plurality of consecutive cycles of the AC power supply voltage waveform,
wherein, within each of the AC half cycles, the the control module increases the PWM duty cycle from a target duty cycle value to provide an increase level of current draw by the motor from the power supply within a first segment of the AC half cycle, and reduces the PWM duty cycle from the target duty cycle value to provide a reduced level of current draw by the motor from the power supply within a second segment of the AC half cycle,
wherein the first segment is located at least partially within a first half of the voltage timeline of the AC half cycle and the second segment follows the first segment and is located at least partially within a second half of the voltage timeline of the AC half cycle.
2. The power tool of claim 1, wherein the first segment starts at a first threshold that is located at or after a first zero-crossing of the AC half cycle and ends at a second threshold, the second segment starts at the second threshold and ends at a third threshold that is located at or prior to a second zero-crossing of the AC half cycle.
3. The power tool of claim 2, wherein the second threshold is between the first threshold and a peak of the DC power bus, and the second threshold is closer to the peak of the DC power bus than the first threshold along a voltage waveform of the DC power bus.
4. The power tool of claim 1, wherein the the target duty cycle is set in accordance with a target rotational speed of the motor.
5. The power tool of claim 1, wherein, within each AC half cycle, the control module is configured to set the PWM duty cycle to zero prior to the first segment and again following the second segment.
6. The power tool of claim 1, wherein the control module is configured to scale the PWM duty cycle from the target duty cycle to a higher value within the first segment of the AC half cycle, and to a lower value within the second segment of the AC half cycle.
7. The power tool of claim 6, wherein the control module is configured to scale the PWM duty cycle within the first and second segments of the AC half cycle to obtain a higher power factor than without the scaling of the PWM duty cycle.
8. The power tool of claim 6, wherein the control module is configured to scale the PWM duty cycle by a factor of 1.1 to 1.3 within the first segment of the AC half cycle, and by a factor of 0.85 to 0.99 within the second segment of the AC half cycle.
9. The power tool of claim 1, wherein the control module is configured to set a conduction band associated with each phase of the stator to a set conduction band value, and, for each phase of the stator, drive two of the plurality of motor switches associated with the phase of the stator within the conduction band.
10. The power tool of claim 9, wherein the control module is configured to scale the conduction band from the set conduction band value to a higher value than the set value within the first segment of the AC half cycle, and to a lower value than the set conduction band value within the second segment of the AC half cycle.
11. The power tool of claim 10, wherein the control module is configured to set the conduction band to 120 degrees and scale the conduction band to the higher value in the range of 130 to 150 degrees within the first segment of the AC half cycle, and to the lower value in the range of 100 to 119 degrees within the second segment of the AC half cycle.
12. A power tool comprising:
a control module configured to control a supply of electric power from the power supply to the motor by controlling a switching operation of the plurality of power switches, the control module being configured to set a conduction band associated with each phase of the stator to a set conduction band value, and, for each phase of the stator, drive two of the plurality of motor switches associated with the phase of the stator within a duration of the conduction band,
wherein, within each of the AC half cycles, the control module increases the conduction band from the set conduction band value to provide an increased level of current draw by the motor from the power supply within a first segment of the AC half cycle, the reduces the conduction band from the set conduction band value to provide a reduced level of current draw by the motor from the supply within a second segment of the AC half cycle,
13. The power tool of claim 12, wherein the first segment starts at a first threshold that is located at or after a first zero-crossing of the AC half cycle and ends at a second threshold, the second segment starts at the second threshold and ends at a third threshold that is located at or prior to a second zero-crossing of the AC half cycle.
14. The power tool of claim 12, wherein the control module is configured to set the conduction band to zero between the first zero-crossing of the half cycle and the first threshold, and between the third threshold and the second zero-crossing of the AC half cycle.
15. The power tool of claim 12, wherein the control module is configured to scale the conduction band within the first and second segments differently to obtain a higher power factor than without the scaling of the conduction band.
16. The power tool of claim 12, wherein the control module is configured to set the conduction band to 120 degrees and scale the conduction band to a higher value in the range of 130 to 150 degrees within the first segment of the AC half cycle, and to a lower value in the range of 100 to 119 degrees within the second segment of the AC half cycle.
17. The power tool of claim 12, wherein the control module scales the conduction band in such that an average power within the half cycle produces a target rotational speed of the motor.
a control module configured to control a switching operation of the plurality of power switches to supply an average current from the power supply to the motor, the control module being configured to control the switching operation of the plurality of power switches within each half AC half cycle of a plurality of consecutive cycles of the AC power supply voltage waveform such that, within a first segment of the AC half cycle, the control module scales up the switching operation of the plurality of power switches such that the inverter circuit supplies more current than the average current from the power supply to the motor, and within a second segment of the AC half cycle, the control module scales down the switching operation of the plurality of power switches such that the inverter circuit provides less current than the average current from the power supply to the motor,
19. The power tool of claim 18, wherein the control module is configured to set a pulse-width modulated (PWM) duty cycle of the inverter circuit to a set value in accordance with a target rotational speed of the motor and control the switching operation of the plurality of power switches by pulse-width modulation at the PWM duty cycle,
wherein the control module is configured to scale the PWM duty cycle from the set value to a higher value than the set value within the first segment of the AC half cycle, and to a lower value than the set value within the second segment of the AC half cycle.
20. The power tool of claim 18, wherein the control module is configured to set a conduction band associated with each phase of the stator to a set conduction band value, and, for each phase of the stator, drive two of the plurality of motor switches associated with the phase of the stator within the conduction band,
wherein the control module is configured to scale the conduction band from the set conduction band value to a higher value than the set value within the first segment of the AC half cycle, and to a lower value than the set conduction band value within the second segment of the AC half cycle.
9240749 January 19, 2016 Green
9871484 January 16, 2018 White
20050073287 April 7, 2005 Ball
20110056715 March 10, 2011 Vanko
20110118890 May 19, 2011 Parsons
20150028790 January 29, 2015 Qu
20160359437 December 8, 2016 Hijikata
20170222561 August 3, 2017 Ivankovic
20180294754 October 11, 2018 Takeda
Assignee: Black & Decker Inc. (New Britain, CT)
Inventors: Alexander Manasseh (Cockeysville, MD), Scott J. Eshleman (Parkville, MD), Robert A. Usselman (Forest Hill, MD), John D. Cox (Lutherville, MD)
Primary Examiner: Muhammad S Islam
Assistant Examiner: Devon A Joseph
Current U.S. Class: With Reference Voltage Circuitry (323/281)
International Classification: B25B 21/00 (20060101); H02P 6/00 (20160101); H02P 23/26 (20160101); H02P 6/15 (20160101); H02P 6/32 (20160101); B23B 45/02 (20060101); H02P 6/08 (20160101); H02P 6/20 (20160101); H02P 6/24 (20060101);


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