METHOD AND APPARATUS FOR SWITCHING AN AC MACHINE BETWEEN A DRIVE AND A POWER SUPPLY

摘要

A method and apparatus for transferring an AC machine between non volts per hertz drive and a power supply such as supply mains, or a generator. In a transfer procedure, the motor drive is placed in a quasi-voltage mode prior to transfer to permit the output of the motor drive to be synchronized to the output of the power supply. In capture procedure, the output of the drive is preconditioned based on detected states of the AC machine to synchronize the voltage at the terminals of the AC machine with the output of the drive. During the capture procedure, opening of a contactor is detected by comparing the frequency and/or voltage at the terminals of the AC machine with that of the power supply.