A Smooth Switching Strategy for Sensorless Control of Permanent Magnet Synchronous Motor Based on Decoupling of Current and Position Dynamics

A smooth switching strategy for sensorless control of permanent magnet synchronous motor based on decoupling of current and position dynamics is proposed to address the issues of slow switching, current dynamics, and speed overshoot when switching from I-F control to sensorless speed control. This strategy uses Park transformation to rotate the current vector angle to ensure that the position error when switching is equal to zero. The electromagnetic torque corresponding to the q-axis current command is equal to the actual required load torque of the motor at the switching instant, and then d-axis current command decreases to zero. The simulation results show that this strategy can achieve fast and smooth switching from I-F control to closed loop.