EMF-based position sensorless control of IPMSM with improved current vector control strategy

This paper studies the sensorless interior permanent magnet synchronous motor (IPMSM) vector control strategy which is based on the EMF sliding-mode observer. As parameters selected for the position observer are obtained mostly by experimental adjustment, a phase locked loop (PLL) parameters design method based on the expected position estimation error is present. To improve the operation efficiency, a maximum torque per ampere (MTPA) control strategy based on current vector angle online tuning is introduced. In this way, the robustness against the motor parameters variations can be enhanced. The main idea is changing the reference of the stator current vector angle by a small value change, and then comparing the corresponding current value to tracking the ideal MTPA trajectory. The experiments on a 2.2kW IPMSM sensorless vector control system verifies the effectiveness of the PLL parameter design method and the MTPA control strategy.