A novel position observer for SPMSM sensorless control at low speed without using filters

This paper focuses on the improvement of pulsating current injection based sensorless control of surface-mounted permanent-magnet synchronous motors (SPMSM). Conventional practice applies band pass and low pass filters to track the position information. However, since filtering effect of low order filter is not ideal, the high order filter is generally used to process the position signal. But this would introduce a certain delay and increase the calculation burden. To solve this problem, a novel position observer is proposed which achieves ideal filtering effect and reduces the computation burden of the system. The experimental results based on RT-LAB platform verify the feasibility of the designed observer.