Adaptable sliding mode observer-based sensorless control with harmonic current compensation for dual three-phase PMSMs

To improve the adaptability of sensorless control in the full-speed range of a dual three-phase permanent magnet synchronous motor (DTP-PMSM), an improved sensorless control strategy based on a variable-gain super twisting algorithm sliding mode observer (VGSTA-SMO) along with harmonic component compensation has been introduced in this paper. First, the super twisting algorithm sliding mode observer (STA-SMO) is introduced to reduce the inherent chattering phenomenon of traditional SMOs. Then, the variable gain of this STA-SMO is designed to improve the observation adaptability at different rotor speeds. Meanwhile, considering that the harmonic components, especially at low rotor speeds, in the stator current can affect the observation accuracy of this VGSTA-SMO, a least mean squares adaptive notch filter (LMS-ANF) is employed to implement online harmonic compensation. Finally, comparative experiments with different methods in the full-speed range are conducted and compared to verify the effectiveness of the proposed novel sensorless control strategy whose observation deviation is about 2% even when the rotor speed is as low as 100 rpm.