Development of adaptive hysteresis band current control strategy of PWM inverter with constant switching frequency

Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drive systems. However the conventional fixed band hysteresis control has a variable switching frequency depending on motor speed and load. In this paper, the adaptive hysteresis band current control strategy is proposed, where the hysteresis band is controlled as variations of motor speed, load current, and neutral point voltage in order to hold the switching frequency constant at any operating conditions. The proposed current control strategy is introduced to the current controller of a vector controlled permanent magnet synchronous motor systems. The proposed strategy is verified by simulations and experiments.