CONTROL METHOD OF PARALLEL OPERATION OF INVERTER FOR SYSTEM INTERCONNECTION

摘要

PURPOSE:To maintain the proper value of power conversion efficiency as the whole inverter system for system interconnection consisting of a plurality of inverters and a DC power supply such as a solar cell respectively. CONSTITUTION:When the sum of the output power of both inverters 2A and 2B detected by an output voltage detector 6 is smaller than a set value thereof, an electromagnetic 3C for varying interconnection among both inverters and both solar cells 1A, 1B is closed, and either one inverter selected in both inverters is supplied with electricity from both solar cells. When the sum of both output power is larger than the set value thereof, the electromagnetic switch 3C is opened. Accordingly, the inverters are operated in both combination of the inverter 2A and the solar cell 1A and the inverter 2B and the solar cell 1B, and the operation of the inverters is controlled in conformity with a specified program in a switching control circuit 7 so as to maintain the proper value of the power conversion efficiency of the inverters by the increase of the load factor of the inverters regarding the inverters selected to be worked.