Research On Ultrasonic Motor Power Supply Based On PSoC

This research activity is funded by National Natural Science Foundation of China Key Programs (Grant No. 50735002).Utilizing the inverse piezoelectric effect of piezoelectric material, elastic body (stator) can generate vibrations in the ultrasonic frequency band, so ultrasonic motor (USM) can be actuated by the friction between the stator and rotor to obtain motion and torque. The demand of its driving control circuit is very different from the traditional electromagnetic motors, because the mechanism of the ultrasonic motor is special. Moreover, the traditional driving method is designed for the motor speed control by modifying the electrical power frequency, so this relative speed control methods are inadequate. In order to enrich the control method, this paper will propose a new type of driving power system to achieve the goals of frequency modulation, voltage regulator and phase modulation, finally for better speed control. The main contents are as follows:1. To USM, the author discussed its characteristics, classification, applications and its speed control features, then described its domestic and international research statuses of driving power supply.2. Based on frequency modulation, voltage regulator, and phase modulation for the speed control requirements, it was proposed to obtain boost circuit and push-pull inverting circuit, contributing to a cascade circuit.3. The advantages and disadvantages of PSoC control chip, and its structure characteristics are described. The overall control process of the motor was proposed, and the voltage booster and isolated electrode voltage feedback circuit. By using LCD1602 display system the motor operating status can be shown in time. Then the working principle of the manual encoder and software control method were induced.4. Making use of UART module, the serial communication between PSoC chip and PC can be realized. Further, the control interface displayed on PC machine was designed by applying VB programming, leading to the achievement of data transmission and reception.5. Experimental research on the driving power was completed in this paper. The key driving signal waveform was measured. Then using series inductance match method to execute the matching experiment, an inductance fabricated by the author was employed in this experiment for testing the matching extent. Ultimately a systemic experiment was finished for testing the motor speed control performance by using the driving power designed in this paper. The results demonstrated that the realization of the motor frequency, voltage and phase control could make its closed-loop speed stable within 5%.