Techniques and Considerations for Driving Piezoelectric Actuators at High-speed

Due to their high stiffness, small dimensions and low mass, piezoelectric stack actuators are capable of developing large displacements with bandwidths of greater than 100 kHz. However, due to their large electrical capacitance, the associated driving amplifier is usually limited in bandwidth to a few kHz. In this paper the limiting characteristics of piezoelectric drives are identified as the signal-bandwidth, outputimpedance, cable inductance, and power dissipation. A new dual-amplifier is introduced that exhibits a bandwidth of 2 MHz with a 100 nF capacitive load. Experiments demonstrate a 20 V 300 kHz sine wave being applied to a 100 nF load with negligible phase delay and a peak-to-peak current of 3.8 A. Although the peak output voltage and current is 200 V and 1.9 A, the worst-case power dissipation is only 30 W.