Control Strategy of High Performance IPMSM Drive in Wide Speed Range

In order to improve the performance, efficiency and reliability of the interior permanent magnet synchronous motor (IPMSM) drive, a set of control strategies are developed for wide speed range operation. A rotor flux oriented vector control with model reference adaptive system (MRAS) based rotor position/speed estimation is employed as the basic control strategy for IPMSM drive. A control strategy named maximum torque per ampere (MTPA) is applied to minimize the motor current magnitude during low speed operation. While an over-modulation method is employed to enhance the voltage transfer ratio of PWM inverter and the output torque capability of IPMSM during high speed operation, and flux weakening control is developed for high speed stable operation of IPMSM drive. Furthermore, phase current reconstruction under over-modulation is taken into account, which lowers the system cost and expands the working range of PWM inverter fed IPMSM motor drives. The issue of seamless switching from MTPA during low speed range to conventional field-weakening control during high speed range is also discussed. Simulation and experimental results demonstrate the feasibility and effectiveness of these control strategies, which realizes the high performance operation of IPMSM drive in wide speed range.