A fast switching method for PM synchronous motor speed control

In the recent years, due to high performance, power density, and less generated noise of permanent magnetic synchronous motors (PMSM), they have received a lot of attention for traction application in land, sea and under sea vehicles. In this paper, a new digital controller is proposed and applied to a PMSM. The proposed control technique adjusts motor current amplitude and phase to achieve different ranges of speed. Several levels of current and power angle are defined for the motor. Fast adaptive switching between these levels is used to achieve the desired speed. However, the control logic is different for below and above motor nominal speed. In this method, the typical PID controllers, which cause complicated control strategies, are removed. This new technique is simple, fast, stable, and reliable to drive PMSM in wide range of speed.