| 摘要 |
PROBLEM TO BE SOLVED: To reduce a loss by reducing zero-phase voltage or zero-phase current generated in an inverter or a linking transformer in a self-excited reactive power compensating device by zero-phase components generated in compensating current command signals for three phases by a compensating current computing circuit. SOLUTION: Compensating current command signals Ic (U phase), IcR (V phase), IcR (W phase) found out from the load currents IL of three phases are added by an adder 9, the added value is multiplied by 1/3 through a 1/3 multiplier 10 to find out a signal I0 only for a zero-phase component and signals obtained by subtracting the signal I0 from each of the signals IcR (U phase), IcR (V phase), IcR (W phase) are defined as final compesating current command signals IcREF (U phase), IcREF (V phase), IcREF (W phase) for controlling respective single phase inverters 5 for the three phases. Since any zero-phase component is not included in the final compensating current command signals IcREF for three phases, an unnecessary loss due to a zero-component is reduced. |
