A Super-Twisting Extend State Observer with High Frequency Signal Injection for Low Speed Sensorless Control of IPMSM

In the context of very low speed sensorless operation of interior permanent magnet synchronous motors (IPMSM), the task of accurately estimating rotor position and speed solely through model-based estimation methods becomes notably challenging. In this paper, a superimposing of high frequency current is injected in the IPMSM with saliency. Adopting the high frequency model, a high frequency super-twisting extended state observer (STESO) is proposed to improve the low speed sensorless performance of IPMSM. The efficacy of the proposed STESO is assessed through experimental investigations encompassing both dynamic and steady-state scenarios. The results demonstrate that STESO can maintain robust tracking performance of motor speed and position under low speed operating conditions.