Research On Micro Power Supply For Piezoelectric Actuator

In recent years,piezoelectric ceramic driving technology has played an increasingly important role in the field of micro-actuated positioning.The piezoelectric inertial motor has features of simple structure,high step resolution,fast response speed,and can easily realize linear and rotary motions;while a ultrasonic motor has features of high efficiency,high rotation speed,self-locking and can respond quickly,and so on.Both have been widely used in the field of micro-driving precision positioning control.Both piezoelectric inertial motors and ultrasonic motors can be used in astronomical telescope fiber positioning systems.This paper focuses on these two kinds of miniaturized motor driving.Based on STM32F031G6U6 microcontroller of the STMicroelectronics,two miniature high-efficiency piezoelectric ceramic driving power are designed using a way of PWM switching.The driving power for piezoelectric inertial motor designed in this paper can produce the high voltage sawtooth wave signal that the inertial motor needs.The power supply is mainly composed of a pre-stage 12V-100V boost section,a post-stage half-bridge section,and an LC low-pass filter section.When driving two piezoelectric inertial motors with an equivalent capacitance of approximately 120 nF,a sawtooth wave of 100 Vpp high voltage,frequency of 5 kHz,and symmetry of 90%is used,and the power consumption of the driving power is approximately 2.5 W.The driving signal of ultrasonic motor are high-frequency AC signals with a phase difference of 90°.The designed driving power of ultrasonic motor is mainly composed of single-chip PWM modulator,H-bridge and LLC filter resonance section.Considering the shortcomings of various current methods for ultrasonic motors,this paper proposes a new,intermittently-activated,speed-regulating method that allows the ultrasonic motor to operate in a step mode,which not only has a wide speed adjustment range,good linearity,but also has features of high precision positioning.An experiment on a self-made ultrasonic motor shows that the minimum step angle is about 0.5×10-3 rad,and the motor speed can be continuously adjusted below 6 revolutions/second.When driving two ultrasonic motors at no-load operation of 0.8 revolutions/second,the total power required by the driving power,including the controller,is approximately 1.08W.Upper computer program based on VB language is designed to communicate with inertial motor driving power through serial port,which can adjust the output number,frequency and other parameters of sawtooth wave in real time;Also in order to facilitate the debugging of the motor,the corresponding controller is designed to communicate with ultrasonic motor driving power through serial port to change the parameters such as motor speed and direction of rotation in real time.The two miniature high-efficiency driving powers designed in this paper are all 85mmx6mm in size.They can independently drive two motors and can be applied to modern fiber optic positioning systems.