PARALLEL OPERATION CIRCUITS OF CONSTANT-VOLTAGE AND CONSTANT-FREQUENCY INVERTER GROUP

摘要

PURPOSE:To control cross current, by mutually adding the respectively detected load current when multiple sets of CVCF inverter group are mutually connected in parallel in their parallel operation. CONSTITUTION:These circuits operate the 1st and 2nd CVCF inverter groups in parallel, of which the 1st inverter group supplies AC power of constant- voltage and constant-frequency at a load 32, the current of which per set is calculated through a detector 31 and a division circuit 33. Each inverter device is composed of a rectifier 11, an inverter 12, a current transformer 13, a cross current computing element 14 and a control device 15. The 2nd inverter group feeds current to a common load 42, the current of which per set then is calculated through a detector 41 and a division circuit 43. On this occasion, between current detectors 31 and 41 provided are points of contact 51 and 52, which are closed with a switch 50 provided between bus bars when both inverter groups are operated in parallel. As a result, the total value of current can be obtained and the cross current controlled properly.