| 摘要 |
PROBLEM TO BE SOLVED: To attain compatibility between the active filter function for turning a power source current into a nearly sinusoidal wave and the power source waveform shaping function for reducing change and distortion of a voltage applied to a load. SOLUTION: This power source voltage adjusting apparatus is provided with a first and a second DC-AC converters 4, 8 of voltage type three-phase PWM inverter constitution in which the respective DC side outputs are connector with a DC smoothing capacitor 3, and controls the first DC-AC converter 4 in accordance with a power source voltage and a load current. While a DC voltage of the DC smoothing capacitor 3 is maintained to be a predetermined value, an adjusting current is combined with a load current supplied to a load 2 from a three-phase power source 1 so as to make a power source current sinusoidal. The second DC-AC converter 8 is controlled in accordance with the DC voltage of the DC smoothing capacitor 3 and the power source voltage. Thereby an adjusting voltage is superposed on the three-phase voltage supplied to the load 2 from the three-phase power source 1 in such a manner that a desired effective value voltage is applied to the load 2. |
