| Abstract |
This paper proposes a low-vibration stopping method by switching the free-run mode and the short-circuit braking mode for compressors. The vibration is generated by the bounce of the rotor caused by the fluctuation of the load torque. The proposed method suppresses the rotor bounce by stopping the motor during the suction process because the compressor does not generate large torque in the suction process. In order to stop the motor during the suction process, the proposed method switches the operation mode form the free-run mode to the short-circuit braking mode at the Top Dead Center, which is starting point of the suction process. Furthermore, the inrush current during the a short-circuit braking mode is suppressed by a hysteresis current controller. The vibration is evaluated under four pressure conditions with the conventional method and the proposed method. As the result, the proposed method achieved more than 58\% reduction of the amplitude of the vibration at all four pressure conditions. Notably, the proposed method reduced the amplitude of the vibration by 71\% under the high-pressure condition. |
