Frequency Adaptive Disturbance Observer for Sensorless Control of a 3 x 3-Phase PMA-SynRM Driven by Mono-Inverter

Sensorless control methods based on flux observer have been widely used in motor drives with medium-high speed operation. However, the conventional methods have some shortcomings in estimation accuracy due to the dc bias caused by the integration, measurement, and parameter uncertainty. In this article, a new frequency adaptive disturbance observer with band-pass filter characteristics is proposed. It is insensitive to dc bias and high-frequency noise, hence improving the robustness of the system. Since the proposed method has no phase delay at any synchronous rotor frequency and can amplify the amplitude of the estimated active flux, it does not need a phase compensation module and can obtain a wider operating range. Moreover, an adaptive extended state observer is added to estimate the disturbance caused by parameter mismatch. The estimated disturbance is fed back to the estimated active flux, which further improves the accuracy of the system. Finally, experiments based on a triple redundant permanent magnet-assisted synchronous reluctance motor are accomplished to verify the effectiveness and accuracy of the proposed observer.