A bilateral capacitance compensation method for giant magnetostriction ultrasonic processing system

Abstract

To improve the capacity and reliability of a rotary ultrasonic machining system, a novel giant magnetostriction ultrasonic processing system (GMUPS) was designed. By using the equivalent circuit model, an optimal compensation model of the GMUPS, with and without a rotary transformer, was proposed. Considering the distributed capacitance of the coil at high frequency, the method of impedance analysis was applied to determine a feasible optimal compensation. To identify the optimal compensation parameters, the characteristics of the GMUPS were studied, including its primary and secondary currents, resonant frequency, and vibration amplitude. The results of the vibration amplitude test demonstrated that impedance analysis was a feasible way to determine the optimal compensation capacitance. The compensation circuit greatly affected the magnitude of the vibration output of the GMUPS, while it did not affect the amplitude-current sensitivity or resonant frequency of the GMUPS. By optimizing the compensation circuit, the impedance of the GMUPS was obviously reduced and the vibration amplitude was maximized. In addition, these results show that impedance analysis can produce a series of relatively optimal compensation capacitances, which makes it greatly useful for adjusting the compensation capacitance as the primary or secondary compensation capacitance deviates from its optimal value.