Improved performance of adaptive hysteresis current controller based vector control of PMSM drive system

The conventional hysteresis current controller has proved that, it is most suitable for current regulated VSI fed ac drives due to its ease of implementation and fast current tracking. However, it has certain limitations like large current ripple in steady state and variable switching frequency operation of IGBT inverter switch during motor load changes. This paper presents an adaptive hysteresis current controller in which the hysteresis band is programmed as a function of motor speed and load current. The proposed current control strategy is applied in the inner control loop of the vector controlled permanent magnet synchronous motor (PMSM) drive system in order to reduce the torque ripple during load variation and the obtained results are compared with conventional hysteresis controller under steady state and transient conditions with fixed and step changes in load. The complete PMSM drive system is modeled and tested in the MATLAB-Simulink environment for effectiveness of the study.