| 摘要 |
PROBLEM TO BE SOLVED: To get balanced three-phase output voltage without affecting current control, even if unbalanced load is connected to the three-phase output of an inverter, by computing a voltage deviation factor by the result of deviation control and a voltage command value, and getting modulated output voltage, and performing the output control, based on this. SOLUTION: A control circuit 205 performs proportion plus integration, based on the difference between a single-phase average value command and an average value, and gets the deviation factor to the single-phase average value command. Multiplying the deviation factor obtained with the control circuit 205 by the phase voltage VLu detected with a voltage sensor in a multiplier enlarges the average voltage deviation obtained with a subtracter. This enlarged voltage deviation is inputted into a voltage control circuit so as to get a large quantity of control. For other two phases, the same processing is performed to balance three-phase voltage on an average. Hereby, even if unbalanced load is connected to the three-phase output of an inverter, the balanced three-phase output voltage can be kept without affecting the current control. |
