Ultrahigh-Voltage Switch for Bidirectional DC–DC Converter Driving Dielectric Elastomer Actuator

Specific applications, such as dielectric elastomer actuators (DEAs) or electroactive polymers, require to switch voltage levels exceeding the ratings of existing semiconductor devices. In low-power application, reversible flyback is widely used to supply DEAs. Lowering the parallel parasitic capacitance of the high-voltage switch is important to improve the energy transfer, while it becomes mandatory to increase the output voltage of flyback above 2.5 kV. In this article, a pulsed transformer gate driver (PTGD) is used to drive series-connected
MOSFET
and, therefore, push the limits from 4.5 to 16 kV. At these high-voltage levels, the structure reveals a drastic voltage unbalance related to the transformer interwinding parasitic capacitance. The compensation method proposed to achieve voltage balance only adds few passive components and reduces significantly the additional parallel capacitance of the switch compared to common load side voltage balancing methods. Finally, and as proof of concept, a half-bridge bidirectional converter was designed from this switch technology and drove an actual DEA at 16 kV.