Sensorless Control of Interior Permanent Magnet Synchronous Motor Drives Considering Resistance and Permanent Magnet Flux Linkage Variation

Extended sliding mode disturbance observer-based current observer for interior permanent magnet synchronous motors (IPMSM) is an efficient method, where the estimated dq-axis disturbances are linearly dependent on the position estimation error. Thus, this article proposed a robust speed-position identification strategy using the estimated disturbances. First, an analysis of the estimated disturbances concerning parameter variation, position estimation error, and the effect on the sensorless control performance is given. Then, a combined method that uses the dq-axis disturbances is proposed for speed-position identification. The proposed method is robust against stator resistance variation without estimating the stator resistance. However, the flux linkage variation effect sustains per the external load. Therefore, the permanent flux linkage variation electromotive force (EMF) compensator is included. The compensator is activated in the medium to the high-speed range while deactivated in the low-speed area. Thus, the advantage of the combined method for the low-speed area against resistance variation is kept. Various hardware-in-the-loop experimental studies and comparative analysis show that the proposed method with a permanent flux linkage variation back EMF compensator achieved an excellent sensorless control performance for IPMSM.