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.