Three Phase Motor Drive Using Space Vector Pulse Width Modulation Technique (SVPWM): The space vector pulse width modulation is a technique, which is used for driving the motor at different frequencies. In recent years, different pulse width modulation techniques are used for driving the ac motors, such as sine wave pulse width modulating (SPWM), unipolar pulse width modulation (UPWM). In these techniques, for generating the PWM two waves are compared. One sine wave with one square wave or one square wave with one dc wave. Here we are presenting ac motor drive by using the space vector pulse modulation technique, which is very advanced and intensive technique for driving the ac motors. In this technique, a triangular wave is compared with the sine wave for generating the PWM, for driving the three-phase ac motor. This comparison is done through the microcontroller 18F452, which is belongs to a pic family. This drive will be made with the help of bridge rectifier for converting the ac into dc, capacitor bank, three phase voltage source inverter for driving the three-phase ac motor, optocoupler and gate driver IC 2104.
Block Diagram of Three Phase Motor Driver Using Space Vector Pulse Width Modulation Technique:
Components List of Three Phase Motor Drive Using Space Vector Pulse Width Modulation Technique:
The Three phase motor drive using space vector pulse width modulation technique has following components list.
- Single Phase AC Supply
- Sigle Phase Step Down Transformer
- Bridge Rectifier
- Voltage Regulator
- Capacitor Bank
- Voltage Source Inverter
- Snubber Network
- IR 2110
- Three Phase Motor.
- Pic Microcontroller 18F452
Single Phase AC Supply:The single-phase ac supply is required for drive this three-phase motor drive. For this purposes the wapda supply is directly connected to this motor drive.
Single Phase Step Down Transformer: In this three-phase motor drive the single-phase step down transformer is used for step down the 220 V ac to 12 V ac.
Bridge Rectifier: The bridge rectifier is used for converting the 12 V ac to dc for supplying the power, to the other electronics components of this drive.
Voltage Regulator: The voltage regulator is used for regulating the 12 V dc to 5 V dc for supplying the power to the microcontroller. The LM 7805 voltage regulator is used in this three-phase motor drive.
Capacitor Bank: In this three-phase motor drive the capacitor bank is connected to the output of bridge rectifier. This capacitor bank is used for two purpose, first one for filtering the dc supply means for removing the ac components from dc voltage and second one for supplying continually dc voltage to voltage source inverter.
Voltage Source Inverter:In this three-phase motor drive the voltage source inverter is used for inverting the dc voltage into three phase ac voltage for driving the three-phase ac motor. This inverter consists of 6 semiconductor switches such as IGBTs or MOSFET, which are connected on three legs. The switches on these three legs are operated, by using the switching technique space vector pulse width modulation.
Snubber Network: The snubber network, which consists of capacitor and resistor, these are connected in series at the output of voltage source inverter. This network is used for removing the voltage or current spikes during the switching of semiconductor switches.
IR 2110: The IR 2110 is a gate diver IC, which is used for giving the gate pulse to the semiconductor switches. Based on this gate pulse the switches are on or off.
Optocoupler: In this three-phase motor drive, the optocoupler is used for interfacing the gate driver IC IR2110 with the microcontroller pic 18F452, which is 6 pin integrated circuit IC. The microcontroller gives the gate signal to the IR2110 through this optocoupler.
Three Phase Motor: The three-phase ac motor is used here as an output load.
Pic Microcontroller 18F452:In this three-phase motor drive, the microcontroller is used for generating the space vector pulse modulation for switching the semiconductor switches. In which high frequency, triangular wave, whose frequency almost 4 K Hz with sinusoidal wave, whose frequency almost 50Hz is compared for generating the vector space pulse width modulation. This vector space pulse width modulation pule is gives to the gate driver IC which drive the MOSFETs or IBGTs switches. The microcontroller is powered up through voltage regulator, which is connected at the output of bridge rectifier.
Working of Three Phase Motor Drive Using Space Vector Pulse Width Modulation Technique:
When this three-phase motor drive is directly connected to the wapda power supply or 220 V ac then these ac voltages are converted into dc through bridge rectifier but these are not pure dc voltage these are basically the pulsating dc voltage. The capacitor bank is connected at the output of bridge rectifier, which removes the ac contents and provide pure dc voltages to the voltage source inverter. The voltage source inverter, which is basically the three phase H bridge consists of semiconductor switches. When these switches are operated through the vector space pulse width modulation technique, which is provide by the microcontroller, then these switches invert the dc voltage in to three phase ac voltage. These three phase ac voltages are used for operating the three-phase ac motor. We can change speed of motor by changing the frequency of vector space pulse width modulation through microcontroller.
Advantages and Applications of Three Phase Motor Drive Using Space Vector Pulse Width Modulation Technique:
- By using this three-phase motor drive we can drive the motor at different speeds in other words we can easily control the motor speed for different loads.
- This space vector pulse width modulation technique generates less total harmonic distortion (THD) contents as compared to the other pulse width modulation techniques.
- This technique provides more efficient supply voltage as compared to other techniques.