Sensorless Control of Permanent Magnet Synchronous Motor Based on Tracking Differentiator-Frequency-Locked Loop and Closed Loop Active Flux Observer

Sensorless control for interior permanent magnet synchronous motor (IPMSM) drives has been proven to be significantly advantageous. However, speed estimation through prior-art synchronization techniques may experience obvious performance degradation under acceleration and deceleration modes. To address this, an estimation scheme based on the tracking differentiator-frequency-locked loop (TD-FLL) is proposed in this paper. Considering the estimated performance degradation of the sensorless control of IPMSM drives caused by DC offset and stator resistance variation, a closed loop active flux observer (CLAFO) is introduced to provides an accurate estimation of the active flux information. Subsequently, a TD-FLL is used to perform accurate speed estimation with the estimated active flux. The proposed estimation scheme is validated by extensive simulation tests.