Three-level hysteresis current control for a three-phase permanent magnet synchronous motor drive

This paper presents a novel three-level hysteresis current control scheme for a three-phase permanent magnet synchronous motor (PMSM) fed by two single-phase four-switch voltage source inverters. Based on two-level hysteresis current control techniques for a single-phase four-switch inverter, a novel three-level PWM method for three-phase PMSM motor is implemented to reduce the magnitude and variation of the switching frequency. To obtain better harmonic performance, an improved variable band hysteresis method for three-level three-phase voltage source inverter is further proposed. Considering three states of output average voltage of the inverter, a new hysteresis controller with variable band calculated by the motor resistance, inductance, DC-link voltage, phase current and back-emf is designed to maintain constant phase leg switching frequencies. The proposed method is simple and effective, and verified by the simulation.