Permanent Magnet Synchronous Motor composite control strategy based on proportional resonance and disturbance observer

A composite control strategy based on proportional quasi-resonance and disturbance observer (PR+DOB) is proposed for low-speed permanent magnet synchronous motor (PMSM) with periodic fluctuations in speed to reduce the periodic fluctuations in torque for smooth speed control of the system. The non-ideal factors causing periodic fluctuations in torque, such as rotor magnetic chain harmonics and inverter dead time, are analyzed and it is found that the non-ideal factors causing periodic fluctuations in torque, such as rotor magnetic chain harmonics and inverter dead time, are disturbances that cannot be observed by conventional disturbance observers. By combining PR control with DOB, the periodic speed fluctuations are suppressed by a resonant controller. Compared to conventional P+DOB control, it is able to suppress the periodic disturbances in the system that cannot be observed by DOB. Finally, the feasibility of the scheme is verified by simulation.