Precise torque control and reliable field-weakening operation of IPMSM

When interior permanent synchronous motor (IPMSM) drive system operates in field-weakening control mode, the magnetic saturation and cross-coupling between d-q axis stator current easily result in the current regulators to appear saturated failure, moreover, modeling uncertainty, temperature and parameters´ changes exist, the current closed-loop control is difficult to achieve precise torque control. Therefore, a novel field-weakening control scheme is proposed to achieve fault-tolerant control of saturated failure and precise torque control by voltage phase control (VPC). Then, the seamless switch criterion is set up between maximum torque per ampere (MTPA) control and field-weakening control. Finally, the system simulation researches are implemented and some conclusions are shown.