Method of and apparatus for detecting shaft position of compressor for air conditioner, and control apparatus for stopping air compressor by using shaft position detecting apparatus

摘要

The load torque of a compressor for circulating refrigerant within a refrigerating cycle changes with the rotational position of the shaft of the compressor, and the phase difference between the primary current and voltage of an induction motor for driving the compressor changes with the load torque. Taking the above facts into consideration, in turning off the compressor driven by the induction motor which is powered with a fixed frequency AC power source, the shaft position of the compressor is detected in accordance with the phase difference, and the current of the motor is turned off at the timing of a particular phase difference when the load torque becomes minimum, thus reducing vibration when the compressor is stopped.