Actuator Power Reduction Using L-C Oscillator Circuits

Piezoelectric actuators are widely used in smart structural systems to actively control vibration and noise, and to enhance performance. Because of the highly capacitive nature of these actuators, special power amplifiers, capable of delivering large currents, are required to drive these systems. The large currents result in excessive heat generation, and are a cause of concern in designing rotating actuation systems with sliprings for power transmission. In this paper, a means of reducing the current drawn from the power amplifier is investigated. This is accomplished by incorporating the actuator in a tuned L-C oscillator circuit. Non-ideal circuit performance is addressed, along with theoretical limits to possible power savings and practical difficulties in achieving them. The practical limitation of the size of a physical inductor needed for this purpose is recognized and the use of an active pseudo-inductor is investigated. This pseudo-inductor is connected in parallel with a commercially available power amplifier and reduction in current drawn from the amplifier is demonstrated.