Patent ID: 11916389
Assignee: DAIHEN CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  B  Y | IPC B  H

Claim 3:
4. A grid interconnection method for a power grid, comprising:
by using a storage battery and a power conversion device for converting power from the storage battery into AC, supplying power from a commercial power supply to a load;
supplying power from the power conversion device to the load when the commercial power supply fails;
causing the power conversion device to synchronize a voltage phase of power supplied from the power conversion device to the load with a voltage phase of power from the commercial power supply when the commercial power supply is restored;
starting supply of power from the commercial power supply to the load after the voltage phase of the power supplied from the power conversion device to the load is synchronized with the voltage phase of the power from the commercial power supply; and
stopping the supply of power from the power conversion device to the load after the supply of power from the commercial power supply to the load is started,
wherein, in order to synchronize the voltage phase of the power supplied from the power conversion device to the load with the voltage phase of the power from the commercial power supply, matching a frequency of the power supplied from the power conversion device to the load with a frequency of the power from the commercial power supply, and
after the matching between the frequencies of the powers, matching a zero crossing point of the power supplied from the power conversion device to the load with a zero crossing point of the power from the commercial power supply.