Actuator Power Reduction Using L-C Oscillator Circuits

Abstract

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.

Active Twist Control of Smart Helicopter Rotor - A Survey

“…Since the piezoelectrics draw power from the helicopter electrical system, models are needed for proper power prediction to help in design of the electrical system. The power consumption depends on the electrical characteristics of the PZT transducer, namely the capacitive and resistive behavior of the actuator, which in turn affects their power consumption characteristics [88][89][90]. A piezoelectric actuator can be treated as a capacitor with power losses.…”

“…This requires bulky and inefficient circuitry which is problem in applications such as helicopters where compact smart systems with embedded electronics is desired and transfer of power from the fixed frame to the rotating frame puts serious restrictions on the slip ring unit. One approach suggested in [90] to reduce the current drawn from the amplifier is by using a tuned L-C oscillator circuit. For a typical helicopter application a physical inductor turns out to be very large.…”

<title>Development of a compact piezoelectric-hydraulic hybrid actuator</title>

“…The effect of the tubing stiffness can be treated as an effective change in the bulk modulus of the fluid. The compressibility of the tubing, /3tube 5 given by1°t ube (6) 48r where d is the inner diameter of the tube and 6r is the radial displacement of the tube, given by dP d+d…”