关键词: 磁悬浮电机, 带速重启, 能量回馈, 电机制动

Abstract: Magnetic levitation motor adopts electromagnetic bearing to support the rotating shaft. When it is applied to the uninterrupted operation occasions and short-term power failure occurs, the motor is required to restart quickly after the power grid is restored, and the magnetic bearing can be continuously powered during the power failure time, so as to avoid the damage of the rotating shaft due to falling. To solve this problem, a highly reliable control strategy for magnetic suspension motor restart after power failure was proposed. When the motor was in high speed and the power grid was cut off, the strategy adopted voltage and current double closed-loop control, and carried out sensorless vector power generation control for the motor. After the power grid was restored, the motor restarted with speed, the outer loop quickly switched to the speed loop, and the motor re-entered the vector electric control mode. When the power grid was powered off and the motor was in low-speed state, the strategy adopted boost energy feedback braking control. After the power grid was restored, the motor was restarted at zero speed after fully braked. Simulation and experimental results verify the effectiveness of the proposed method. Compared with the traditional method of zero-speed restart after complete motor braking, the restart time can be greatly reduced under high-speed power failure.

Key words: bearingless motor, restart with speed, energy feedback, motor braking