Energy recovery power supply for piezoelectric actuator

Piezoelectric actuators are used successfully to enable locomotion of micro-robot such as micro air vehicle with flapping wings. However, the use of piezoelectric actuators presents a major challenge for power electronic design: the input capacitance of such devices makes their use delicate because the instantaneous power may be much greater than the average effective power. Due to this challenge, conventional drive circuits, especially inductor, become too bulky or inefficient in low mass applications. This work describes a converter suitable to drive this kind of actuators with low inductor. Moreover the converter provides for recovery of the energy stored on the actuator capacitance back to the primary power supply when the actuator is not supply. The proposed converter is a DC/AC structure, which is capable of producing a square unipolar AC voltage. In our design, an auxiliary shunt circuits are connected to the actuator. Signal flow graph modeling, analysis and design of such a scheme is presented. Experimental validations have demonstrated the effectiveness of the proposed technique for recovery energy.