High-Voltage High-Power-Density Power Electronics for Emerging Medical, Environmental, and Aerospace Applications

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Abstract:High-voltage low-current power-electronic converters that can deliver voltages between 10s to 100s of kV and currents in the 1-100 mA range play a critical role in many medical, environmental, and aerospace applications, established or emerging. In many of those applications, a compact and lightweight high-voltage power supply is desirable if not essential. Unfortunately, conventional technologies are inefficient, heavy, and bulky. This project seeks to develop a new generation of lightweight and efficient high voltage power converters that will enable many promising applications. The fundamental idea is to leverage radio frequency circuit techniques and the recent introduction of high-performance wide-bandgap semiconductor power transistors. This project will make possible many high-voltage applications that have previously been considered impractical, thereby creating new research and business opportunities. A miniaturized power supply that can reach 10s of kV in a fraction of a millisecond will enhance the portability and safety of X-ray systems. These power supplies can also enable smaller and cheaper particle-beam accelerators to make ion and neutron sources more readily available. These systems can be used to detect harmful substances, explosives and map the distribution of petroleum in an oil well. Other applications can become possible with a dramatic reduction in the size and weight of a high voltage converter, like a new kind of electrohydrodynamic aerial vehicle that uses no moving parts and with very low noise and heat profile.Investigators will develop a small and lightweight dc-dc power converter capable of generating an output voltage close to 100 kV. One of the most promising candidates for such goal is high-frequency multi-stage class-DE rectifiers with inductive isolation. In the principal investigator's previous works on multi-stage class-DE rectifiers, the dc output voltage is limited to the breakdown voltage of capacitors with high-quality factors. With the insertion of an air-core transformer, the output voltage upper limit is enhanced up to the breakdown potential between transformer primary and secondary windings. Parallel-input series-output connection of rectifiers in conjunction with high-frequency operation leads to fast rise and fall times, making the circuit particularly suitable for systems that require pulsed dc voltage. Regarding power density (output power per unit volume) and specific power (output power per unit mass), the developed power converter is expected to be superior to state-of-the-art existing converters by at least an order of magnitude and hence will enable or improve many technologies that require high voltage source. In a later stage of the project, efforts will be made to prove the practicality of the developed high-voltage power supplies by building prototypes of target applications including an electrohydrodynamic aerial vehicle, an X-ray tube, and a neutron source.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.