| 摘要 |
PROBLEM TO BE SOLVED: To realize the digital voltage feedback control with a simple circuit constitution. SOLUTION: The output voltage preset value is updated by the detection of a load current with a first judging circuit 15, which judges the output voltage preset value by stepwise switching, so that the output voltage of an inverter is in an allowed range based on the detection of the load current at the time or system linking. The output voltage preset value from the generation of system service interruption to the cut-off of a linking switch 3 is held as a standby state. After the linking switch 3 is cut off, the output voltage preset value is updated by the detection of the load voltage with a second judging circuit 16, which judges the output voltage preset value by the stepwise switching so that the inverter output voltage is in the allowed range of the inverter output voltage based on the detection of the load voltage in the standby state. A voltage control circuit 12, wherein the first judging circuit 15 sending out the output voltage instruction based on the output voltage preset value by the detection of the load current is switched to the second judging circuit 16 for sending out the output voltage instruction based on the output voltage preset value, by the detection of the load voltage after the switching of the control from a current control mode to a voltage control mode, is provided. |
