An advanced switch between sensorless sinusoidal wave drive and rectangular wave drive has been developed for performance optimization in air-conditioner compressor. The phase difference between the voltage phase and the current phase is controlled to accelerate the frequency in sensorless sinusoidal wave drive, using flux-weakening control. The typical rectangular wave drive is applied to improve the efficiency in lower frequency. The novel drive system consists of the sensorless sinusoidal wave drive system, the rectangular wave drive system and the drive system exchanger which switches drive systems each other for performance optimization. High efficiency and the wide range of frequency have been achieved. The effectiveness of the proposal system is confirmed by simulations and experiments.
