Analysis and Optimization of Open-loop Control Stability of Nine-phase Permanent Magnet Synchronous Motor

An open-loop V/F control method for a nine-phase permanent magnet synchronous motor(PMSM) is studied. Based on the establishment of a mathematical model of the rotor small disturbance based on the fundamental reference frame, the stability of the open-loop control system is analyzed. Based on the traditional V/F control, a feedback link is designed to modulate the inverter output voltage frequency and the motor input instantaneous power disturbance in a proportional relationship to enhance the damping of the rotor system. The inherent instability of the PMSM open-loop control system due to the undamped winding of the rotor is improved. Enables the motor to start smoothly and run stably over a wide frequency range.