| 摘要 |
PROBLEM TO BE SOLVED: To reduce a number of load current detection circuits for detecting a load current, and reduce a manufacturing cost.SOLUTION: A harmonic restraint device with an active filter 3 can suppress a higher harmonic generated in a converter circuit 7 of an inverter device 2 connected to an AC power supply 1. The converter circuit comprises: a three-phase diode bridge 9 that is connected to the AC power supply; a liner reactor 10 that is connected to the three-phase diode bridge; and an electrolytic capacitor 11 that is connected to the liner reactor and the three-phase diode bridge. The active filter comprises load current detection means for detecting a load current to the converter circuit, and the load current detection means comprises: a bus bar current detection circuit 12 that detects a bus bar current flowing in the liner reactor; and a phase voltage detection circuit that detects a phase voltage of the AC power source, and the load current is calculated on the basis of the bus bar current detected in the bus bar current detection circuit and the phase voltage detected in the phase voltage detection circuit.SELECTED DRAWING: Figure 1 |
