With Loads of New Electronics Coming Online, Navy Seeks Shipboard Power Management Solution
The Navy is investing hundreds of millions of dollars in state-of-the art technologies such as lasers, rail guns and assorted radar and sensor suites. What it doesn’t have, however, is a ship that can power all of those systems at once.
That’s why the Office of Naval Research is developing new electrical components and systems to help the service better distribute and manage its power supply, Sharon Beermann-Curtin, ONR’s power and energy technical lead, told National Defense in September.
The idea is to be able to move the power available on the ships today “when you want and where you want, on demand,” she said.
If the Navy can't get a handle on this problem, it risks having to build one ship for a rail gun, one ship for a radar, and so on, she said. “What you want to do is ... [to] allow all of these multiple functions in one ship."
The Navy also wants enough energy to optimize the performance of all of its onboard systems, she said. For example, some radars are energy elastic and can have a longer range if given more power, she said. Other weapon systems can shoot targets at a greater distance when consuming more electricity.
Currently, Navy vessels are limited in the way that they source power and move it among its various components. The DDG-1000, for instance, is electrically propelled but uses auxiliary turbines to power weapons and sensor systems, Beermann-Curtin said.
“What we want to do is be able to use the propulsion power, as well as any other power and then put the power where we want it, when we want it,” she said. "We want to make everything very flexible,” including being able to store energy for later use.
Developing the necessary technologies and putting it onto a ship will be a long process, Beermann-Curtin said. So far, ONR has undertaken basic research on subsystems and components, including energy storage, controls and new, more-efficient silicon carbide power converters. The next step will be designing a system architecture that takes into account safety, stability and maintainability, she said.
ONR has founded a research-and-development consortium comprising nine universities with expertise in electrical engineering. The participants develop and test new technologies and components, she said. Using a physics-based modeling tool, the consortium can simulate how an electrical system would perform with both new and old components and obtain data on potential vulnerabilities.
The consortium’s goal is to create a 100-megawatt system with 20 kilovolts of direct current that can fit it into the DDG-51 hull, she said. Meeting the size and weight requirements is a major challenge for the project.
ONR is also focusing on increasing the autonomy of electronic systems, so that sailors wouldn’t have to manually control how power is distributed, but could make adjustments as needed, she said.
Eventually, Beermann-Curtin would like to produce a prototype electrical system on land, which would test the systems architecture and evaluate component performance. Her team has not yet secured the funding to do so, but a working prototype could be built and demonstrated as early as 2022, she said.
ONR’s research would likely apply to future ships because “it would be too expensive to backfit an entire electrical system design” on a legacy vessel, she said.
Potential system designs may require radical changes in how vessels are powered, including revisiting Thomas Edison and Nikola Tesla’s debate between direct and alternating current, she explained. Today, most electrical systems — including those on the majority of Navy ships — use alternating current. Only the DDG-1000 incorporates both direct and alternating current. However, with recent advancements in solid-state power converters, it may be more efficient to power vessels with direct current, Beerman-Curtin said.
ONR and its consortium have developed 3-megawatt silicon carbide power converters that perform at higher voltages and frequencies than the legacy equipment, as well as reducing volume by 60 percent and weight by 30 percent, she said.
“With the silicon carbide [converters], we have built and proven the weight and volume reductions, and then the ability to control the power very, very precisely and safely,” she said.
"If you just stayed with the silicon semiconductors that you use today, they get very cumbersome. You would need like, a thousand of them versus 10,” she added.