A Speed Sensorless Control Method for Permanent Magnet Synchronous Motor Based on Super-Twisting Sliding Mode Observer

• Main Authors: Guo, Leilei, Wang, Huaqing, Jin, Nan, Dai, Linwang, Cao, Lingzhi, Luo, Kui
• Format: Conference Proceeding
• Language: English
• Subjects: Force; Observers; Permanent magnet motors; permanent magnet synchronous motor; Phase locked loops; phase-locked loop; Rotors; second-order general integrator; Sensorless control; speed sensorless; super-twisting sliding mode observer; Synchronous motors
• ISSN: 2158-2297
• DOI: 10.1109/ICIEA.2019.8834074

Sliding mode observers are often utilized to achieve the speed sensorless control of permanent magnet synchronous motors. However, due to the nonlinearity of the sampling channel, DC offset is often contained in the sampled voltages and currents of the permanent magnet synchronous motor, which may further reduce the speed sensorless control accuracy. Besides, the speed sensorless control accuracy is usually very poor due to the low signal-to-noise ratio in the low speed region. In this paper, to improve the speed sensorless control accuracy in the low speed region and remove the effects of the DC offset, a new super-twisting sliding mode observer based speed sensorless control method is proposed for permanent magnet synchronous motors. First, based on the concept of the equivalent feedback, a new super-twisting sliding mode observer is proposed. Second, the effects of the DC offset on the speed sensorless control are analyzed in detail, and a second-order generalized integrator is used to remove the DC offset contained in the observed equivalent feedback signal. Then, a phase-locked loop is used to estimate the speed and the rotor position to achieve speed sensorless control. Finally, the effectiveness of the proposed control strategy is verified by a 6.6 kW permanent magnet synchronous motor speed sensorless control system.