Leakage current characterization and compensation for piezoelectric actuator with charge drive

•It is proved that leakage current is mainly determined by the voltage on actuator.•A compensation circuit for charge drive is proposed.•Displacement drift rate is decreased from 0.9 nm/s to lower than 0.033 nm/s.

In this paper, the effects of leakage current on piezoelectric actuators with charge drive are presented, and a method to compensate it is proposed. Considering a piezoelectric stack driven by a switched capacitor charge pump as an example, the leakage current was found to be dependent on the voltage applied on the actuator but had a negligible relationship with the driving routes. The nonlinear relationship between the leakage current and the voltage was investigated, and a feedback circuit based on the applied voltage of the actuator was used for compensation. Experimental results showed that a displacement drift rate of lower than 0.033 nm/s could be achieved with an applied voltage from 0 V to 60 V, whereas the drift rate was as large as 0.9 nm/s without compensation.