A high-efficiency and low-energy consumption inverter circuit design for single-phase piezoelectric motor

This paper presents an efficient drive scheme based on the E-type inverter to address the issue of low efficiency in piezoelectric motor drive circuit design caused by switching losses. Initially, the impedance of the L1B2 single-phase piezoelectric motor is analyzed using the BVD equivalent circuit model, and the motor’s equivalent circuit parameters are determined through impedance experiments. Subsequently, through dimensionless analysis and the introduction of state variables, the differential equations for the E-inverter’s switching states are derived. This ensures that the switching current and voltage waveforms do not overlap during the switching process, facilitating efficient energy conversion with minimal loss. Furthermore, taking into account piezoelectric loss and mechanical quality factor, the optimal driving frequency is determined between the resonant frequency and the anti-resonant frequency. Based on this, a matching circuit is designed to ensure that the motor operates at the optimal frequency with resistive load, thereby maximizing motor conversion efficiency. The circuit parameters at the resonant frequency and the optimal frequency are accurately determined using the exponential matrix method. Simulation and experimental results demonstrate that the designed drive circuit effectively outputs sinusoidal waveform, meeting the driving requirements of the piezoelectric motor. The efficiency of the drive circuit at the optimal frequency is increased by 18.3% compared to that at the resonant frequency, and the temperature rise of the piezoelectric ceramic is relatively reduced by 0.4 °C.