Dynamic Compensation System Of Passive Controllable Reactor For Piezoelectric Actuator

Piezoelectric actuator is a new type of actuator which uses new materials and new principles.Based on the converse piezoelectric effect, piezoelectric actuator converts electricity tomechanical energy and then outputs the mechanical energy to drive load through the mechanicalmechanism. It has many superior characteristics，such as quick response, large deformation, highoutput force, high resolution of displacement and volumetric efficiency, etc. Therefore, it is widelyused in ultrasonic motors, ultrasonic transducer, vibration control and other fields. The impedancecharacteristic of piezoelectric actuator is capacitive and the capacitance of the piezoelectric actuatorvaries greatly with the load, the drive’s frequency and the temperature. In order to improve theefficiency of the driver of actuator, a parallel inductance is often used toachieve reactive power compensation. This paper designs a dynamic compensation system of passivecontrollable reactor for piezoelectric actuator.A theoretical analysis is made of the feasibility of the scheme and the dynamic compensationperformance of the whole system is verified by the experiment results. The main accomplished workis as follows:Firstly the characteristics and applications of the piezoelectric actuator, requirements of the useof driver, the present situation and the development, the principle of controllable reactor areintroduced.The principle of passive controllable reactor is proposed, including the controllable reactormodel and its optimization design based on two-winding transformer, controllable reactor model,and its optimization design based on three-winding transformer.The implementation scheme of passive controllable reactor is elaborated. One is to use a digitalpotentiometer to achieve controllable reactor, another is to use a motor potentiometer to achievecontrollable reactor. Analyzing the possibility of achieving capacitive characteristics of thecontrollable reactor.The control system of passive controlled reactor is designed, the features of the control chipTMS320F2812is elaborated, the hardware design and software design of the whole controlsystem is given.The passive controllable reactor system is verified by the experiment, including realizing thecontrollable reactor based on digital potentiometer under low voltage, the contrast experiment of controllable reactor based on two-winding transformer and three-winding transformer by usingmotor potentiometer under low voltage, the contrast experiment of dynamic compensation andfixed compensation under high voltage, observing the controllable reactor has an impact on theperformance of the piezoelectric actuator or not at the same time.