Ultra-High-Voltage (7-kV) Bidirectional Flyback Converter Used to Drive Capacitive Actuators

• Published in: IEEE transactions on industry applications Vol. 57; no. 5; pp. 5145 - 5156
• Main Authors: Mottet, Raphael, Almanza, Morgan, Pniak, Lucas, Boegli, Alexis, Perriard, Yves
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.09.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Actuators; Bidirectional control; Capacitance; Capacitive parasitic elements; Charge efficiency; Converters; Design factors; dielectric elastomer actuators (DEAs); Discharges (electric); Efficiency; Elastomers; Electrodes; flyback converter; High voltages; Inductors; Magnetic cores; pulse gate driver transformer; Switches; Topology; ultra-high-voltage gain
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2021.3094460

Dielectric elastomer actuators (DEAs) have extremely advantageous characteristics such as lightness, compactness, flexibility, and large displacements. However, in order to operate, they can require voltages in the order of several thousands of volts. Thus, to unleash the full potential of DEAs, it becomes essential to be able to generate and manipulate such voltages with an electronics as compact and efficient as possible. While previous works showed that it was possible to implement a system capable of supplying voltages of up to <inline-formula><tex-math notation="LaTeX">{\text{2.5}}\;{\text{ kV}}</tex-math></inline-formula> and recovering part of the energy stored in DEAs (due to their capacitive nature), no work managed to go over that threshold for two main reasons: first, due to the absence of switches capable of withstanding more than <inline-formula><tex-math notation="LaTeX">{\text{4.5}}\;{\text{ kV}}</tex-math></inline-formula>, and, second, due to parasitic capacitances of the flyback's coupled inductor, which steal an increasingly large part of the energy destined for the load when the output voltage is higher. This article, therefore, proposes a global design, where the factors limiting the increase in the output voltage have been mastered. Through a careful design of the coupled inductor combined with the use of mosfet s put in series, thanks to the pulsed transformer gate drive topology to handle the high voltages, this work goes beyond the current state of the art. Indeed, here, we present various strategies undertaken, which led to the manufacture of a bidirectional flyback converter capable of amplifying an input voltage of <inline-formula><tex-math notation="LaTeX">{\text{12}}\;{\text{ V}}</tex-math></inline-formula> to more than <inline-formula><tex-math notation="LaTeX">{\text{7}}\; {\text{kV}}</tex-math></inline-formula> across a capacitive load and recuperating parts of the energy stored. A preliminary study of the efficiency shows an approximate <inline-formula><tex-math notation="LaTeX">\text{{58}{\%}}</tex-math></inline-formula> efficiency during the charge phase from <inline-formula><tex-math notation="LaTeX">{\text{0}}\;{\text{ V}}</tex-math></inline-formula> to 7 kV and a <inline-formula><tex-math notation="LaTeX">\text{{54}{\%}}</tex-math></inline-formula> efficiency during the discharge phase.