| 摘要 |
PURPOSE:To suppress fluctuation of DC voltage to be applied on a DC smoothing capacitor by performing phase correction control of inverter output voltage in proportion to the actual value of operated reactive component of instantaneous power system voltage. CONSTITUTION:Upon occurrence of imbalance in the three-phase voltage in a power system 1, actual value of the reactive component of instantaneous system voltage is calculated in a reactive component operating unit 9 and multiplied by a predetermined constant, and then the product is added to a control signal provided from a phase regulator 5c, in an adder 10b, thus correcting the control signal. Consequently, the reactive component of the instantaneous inverter output voltage is controlled to be equal to the reactive component of the instantaneous system voltage, three-phase imbalance of the output current I1 from an inverter 2 is controlled to be within an allowable range and charge/ discharge operation of a DC smoothing capacitor 3 is also controlled. Since DC voltage across the DC smoothing capacitor 3 does not fluctuate, a voltage type inverter can be operated continuously. |
