SINGLE-PHASE AC SYNCHRONOUS MOTOR AND METHOD FOR CONTROLLING SAME

摘要

Any one or more of the following are achieved: reducing the occurrence of vibration occurring at start time; reducing the power consumption when starting up a plurality of motors at one time; and performing more smooth drawing into a synchronous rotation. A control unit (19) controls the switching of start-up switching elements (21 to 24) according to the detection signal of a sensor (32), performs a first start-up operation and a second start-up operation, and then constitutes a single-phase AC synchronous motor (1) that moves to a synchronous operation. In the first start-up operation, the duty of a voltage applied to a motor coil (30) is gradually increased to gradually increase the applied voltage. In the second start-up operation, when the rotational speed of a permanent magnet rotor (31) reaches a predetermined rotational speed in the vicinity of a synchronous rotational speed, the switching of start-up switching elements (21 to 24) is controlled according to an internal synchronization signal generated based on the frequency information of a single-phase AC power supply (2) previously obtained in place of the detection signal of the sensor (32).