Design and implementation of a lightweight high-voltage power converter for electro-aerodynamic propulsion

Abstract

Recent studies in electro-aerodynamic (EAD) propulsion have stimulated the need for lightweight power converters providing outputs at tens of kilovolts and hundreds of watts [1] [2]. This paper demonstrates a design of a lightweight high-voltage converter operating from a 160-200 V dc input and providing dc output of up to 600 W at 40 kV. It operates at around 500 kHz and achieves a specific power of 1.2 kW/kg. This is considerably lighter than comparable industrial and academic designs at this power level. High voltage converters generally comprise an inverter, a step-up transformer and a rectifier, with the large needed voltage gain distributed among these stages. Several means of realizing these stages are compared in terms of weight. The weight of the converter is minimized by properly selecting and optimizing the design and the voltage gain of each stage within the constraints of device limitations and losses. A prototype circuit is developed based on this approach and used to drive an EAD-propulsion system for an unmanned aerial vehicle (UAV). In addition to addressing the power conversion needs for EAD, this research can potentially benefit the development of lightweight high-voltage converters in many other applications where weight and size are important.

Electrohydrodynamic propeller for in-atmosphere propulsion; rotational device first flight

“…2b, flies higher from the central area of the cylinder where the electric field is more intense. The 6-blade propeller (7) has more of a stable sideways flight (Fig. 2c) with many partial discharges between the blades and the central pin.…”

“…For instance, propeller (4) detached from the HV pin and flew at negative 54 kV in a metal cylinder 29 cm in diameter and 60 cm in height while a liftoff was also obtained at negative 16.9 kV in a cylinder 7.5 cm in diameter and 5.4 cm in height. propeller 4) designed with copper tape and one pin per blade; the applied voltage was -25.8 kV in a 10.5 cm diameter, 11 cm height grounded copper cylinder; (b) liftoff of propeller (7) at -36 kV. The last two points on the chart were recorded after liftoff.…”

Diode Evaluation and Series Diode Balancing for High-Voltage High-Frequency Power Converters

“…We drive all of the diode rectifiers with a custom-built inverter and transformer [5]; a simplified schematic for this system is shown in Fig. 12.…”

“…This motivates increasing switching frequencies from a few hundred kHz and below to the high hundreds of kHz and MHz range. One of the bottlenecks to achieving high frequency at high output voltage while preserving high efficiency is the lack of low-loss high-voltage diodes capable of operation at high frequency [5], [11]. Si Schottky diodes are appealing in high frequency applications but they are mostly rated below 250 V [12]; commercially available Silicon Carbide (SiC) diodes exhibit low loss and can block up to 3.3 kV; however, above 5 kV, the only presently affordable and available diodes are Si high-voltage diodes [12].…”

“…One can use such high-frequency, low-loss low-voltage diodes in various ways to achieve a high-voltage output. One can (1): have multiple transformer windings or multiple resonant tanks that are separately rectified and stacked in series (e.g., [4], [8], [13]); (2): Use the diodes in voltage multiplying rectifier topologies (e.g., [5], [9], [14]- [16]); and/or (3): Series connect discrete low-voltage diodes to construct an approximate equivalent to a high-voltage diode (e.g., [17]).…”