Synchronous power-on/off control method and synchronous power-on/off controller

A synchronous power-on/off controller in which a power-on/off command is output to a breaker for switching in a case where a frequency difference between a plurality of electric power supply sources is within a predetermined range and a phase difference between the plurality of electric power supply sources is within a predetermined range, in switching of electric power supply between the plurality of electric power supply sources, at least one of the plurality of electric power supply sources including an electric generator which is driven by a driving power source via a transmission device, the synchronous power-on/off controller comprising:

• a frequency difference detector which detects the frequency difference between the plurality of electric power supply sources;
• a phase difference detector which detects the phase difference between the plurality of electric power supply sources;
• and
• a synchronous power-on/off control unit which determines whether or not the detected frequency difference is within the predetermined range and whether or not the detected phase difference is within the predetermined range, generates the power-on/off command, and outputs the power-on/off command to the breaker,
• wherein the synchronous power-on/off control unit feedback-controls a generator drive rotation speed of the transmission device so that the frequency difference is maintained at a value within the predetermined range and the phase difference is maintained at a value within the predetermined range, in a case where the synchronous power-on/off control unit determines that the detected frequency difference is within the predetermined range and the detected phase difference is within the predetermined range,
• wherein the synchronous power-on/off control unit controls the generator drive rotation speed of the transmission device by providing an offset to a rotation speed command of the transmission device, in a case where the synchronous power-on/off control unit determines that the detected frequency difference is not within the predetermined range and the detected phase difference is not within the predetermined range, and
• wherein the synchronous power-on/off control unit calculates a generator rotation speed command by adding to the rotation speed command of the transmission device an output value obtained by subjecting the detected phase difference to a proportional-integral-control, feedback-controls the generator drive rotation speed based on the generator rotation speed command, and outputs the power-on/off command to the breaker, in a case where the synchronous power-on/off control unit determines that the detected frequency difference is within the predetermined range and the detected phase difference is within the predetermined range.