Sensorless Control Based on the Uncertainty and Disturbance Estimator for IPMSMs With Periodic Loads

The research object in this article is a single rotor compressor based on the interior permanent magnet synchronous motors with sensorless control, whose load fluctuates periodically with the mechanical angle. The periodically fluctuating loads can cause obvious periodic fluctuations of motor speed. Meanwhile, the traditional phase-locked loop (PLL) can lead to obvious phase shift and amplitude attenuation. Therefore, the controller is designed from two aspects to make the motor run stably at low speed under the periodic load. First, a speed control based on the uncertainty and disturbance estimator (UDE) is proposed to suppress speed fluctuations caused by the periodic load. Second, the phase-locked loop based on the resonance control (R-PLL) is proposed to compensate for the periodic angle and speed errors caused by the phase shift coming from the PLL under the periodic load. The experimental results show that the sensorless control based on the R-PLL and UDE can effectively improve the estimated angle accuracy and suppress the speed fluctuations, making the motor run stably at low speed under periodic loads.