Zhang Haigang's scientific contributions

One types of permanent-magnet ac motor drives are available in the drives industry. These are the permanent-magnet synchronous-motor (PMSM) drive with a sinusoidal flux distribution. The application of vector control to the PMSM and complete modeling, simulation, and analysis of the drive system are given. State-space models of the motor and speed controller of the inverter switches and vector controller are included. Performance differences due to the use of pulse width modulation (PWM) and hysteresis current controllers are also examined. Particular attention is paid to the motor torque pulsations and speed response. Some experimental verification of the drive performance is also given �� presents the mathematical model of the PMSM. Using this model, vector control of the PMSM is developed in Section III. The operation of the current controllers used in high-performance servo drives are discussed in Sections IV and V while the structure of the entire drive system is explained in Section VI. Sections VII and VIII have the results and conclusion, respectively. II. MACHINE MODEL