Sensorless Control of Permanent Magnet Synchronous Motor Based on Tracking Differentiator-Frequency-Locked Loop

Sensorless control technique is regarded as the enabler of the reliability improvements for interior permanent magnet synchronous motor (IPMSM) drives. However, the conventional estimation schemes by using the phase-locked loop (PLL) and the frequency-locked loop (FLL) may experience undesired accuracy under acceleration and deceleration cases (ADCs). To address this, a speed estimation scheme by combining a closed-loop active flux observer (CLAFO) with a tracking differentiator-based frequency-locked loop (TD-FLL) was proposed in this paper. Starting from a brief introduction of the conventional PLL performance analysis with - and FLLADCs based estimation schemes, a detailed is provided. Accordingly, an estimation scheme based on the TD-FLL is elaborated. Considering the performance of the proposed TD-FLL scheme is adversely affected by various disturbances, a CLAFO is carefully designed to improve the disturbance immunity of the proposed TD-FLL scheme. Extensive experimental tests are conducted to verify the effectiveness of the proposed TD-FLL scheme under different test cases.