| 摘要 |
PROBLEM TO BE SOLVED: To prevent the compensating ratio of higher harmonic from being lowered even when the fundamental wave of load current is unbalanced. SOLUTION: This device is provided with a load current fundamental wave anti-phase component arithmetic circuit which consists of an anti-phase three-phase two-phase conversion circuit 20 which converts an anti-phase component of load current detection value from a three-phase into a two-phase, a 1st anti-phase component arithmetic circuit 21 which calculates an anti-phase effective component and anti-phase ineffective component of load current from the output signal and an output signal of a phase-locked loop, a 1st anti-phase detection lowpass filter 22 which takes out a direct current component of the anti-phase effective component signal, a 2nd anti-phase detection lowpass filter 23 which takes out a direct current component of the anti-phase ineffective component signal, a 2nd anti-phase component arithmetic circuit 24 which operates an anti-phase fundamental wave component of the load current in two-phase from an output signal of each-phase detection lowpass filter and an output signal of the phase-locked loop and an anti-phase component two-phase three- phase conversion circuit 25 which converts the output signal form two-phase into three-phase. An output signal of a fundamental wave adder 26 which adds each output signal of a two- phase three-phase conversion circuit 15 and the anti-phase component two-phase three-phase conversion circuit is inputted as a subtraction element of a 1st a subtracted 16. |
