| 摘要 |
PURPOSE: To perform high accurate compensation for harmonics by adding the harmonics obtained by adding an active filter current to a load current to a compensating command value computed on the basis of the load current as a correction value. CONSTITUTION: In a control device 22, the functions of detecting and correcting a harmonic current ISH made to flow into an active filter(AF) from a power supply is added to the function of a harmonic detection circuit 23. To the input stage, a current transformer 24 for detecting the current IAF, of the AF, an adder 25 for adding a load current IL to the detected current IAF and a changeover switch circuit 26 for switching and inputting the added value (IAF+IL) and the load current IL to the harmonic detection circuit 23. Namely, the harmonic current ISH made to flow into the AF from the power supply is obtained from the addition of a harmonic current ILH contained in the load current IL and the AF current IAF and added to a harmonic current ILH separated and extracted from the load current IL as a connection value, thereby obtaining a compensating aommand value IREF. |
