The main purpose of this study is to design the power electronics to drive a 1 W piezoelectric actuator for micro-robotic applications, such as flapping-wing robotic insects. The voltage requirement of the piezoelectric actuators is about 200 V, but most of the energy sources do not exceed 5 V. In this paper, we propose a two stages converter suitable to drive this kind of actuators. The first stage of the proposed converter is a DC/DC converter which can have lightweight and high voltage gain for the biasing of the piezoelectric actuator. The second stage of the proposed converter is a DC/AC converter which is capable of producing an arbitrary unipolar AC voltage to supply the piezoelectric actuator. Because the switching loss is frequently the dominant loss in high-voltage/low-power switching amplifiers, a wideband zero-voltage-switching (ZVS) half-bridge circuit is introduced. In our design, two auxiliary shunt circuits are connected to the input terminal in order to ensure the ZVS condition in a wide bandwidth. Each auxiliary shunt circuit includes a diode, a switch and an inductor. The auxiliary inductor exhibits a small inductance and is not in the path of the major power flow, thus it can be implemented by the parasitic inductance of the connection wires or by PCB tracks.
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