Adaptive Full-Order Observer Analysis and Design for Sensorless Interior Permanent Magnet Synchronous Motors Drives

This article proposes a straightforward design guideline and analysis of adaptive full-order observers for rotor position and speed estimation of interior permanent magnet synchronous motors (IPMSM) sensorless drives. The adaptive observer is built upon the IPMSM extended electromotive force model in the stationary reference frame. The design of the adaptation and feedback gains is performed by a cascade approach, where state observer and adaptive law operate at distinct frequencies. Since speed estimation error impacts the system stability, this issue is the focus of the high-bandwidth state observer design. On the other hand, the adaptive feedback loop, which operates at lower frequencies, ensures good rotor speed estimation performance. The effect of synchronous inductances and stator resistance variation on the estimation of the mechanical variables is investigated and analytically described. Experimental results validate the adaptive observer design method and the parameter variation analysis under sensorless vector control.