The utility model discloses an active filter based on friendship direct transform ware and even -order harmonic modulation technique are kept apart to high frequency, three -phase APF owner power circuit has, wherein every single -phase APF owner power circuit adopts and recommends forward mode high frequency isolation friendship direct transform ware and capacitor parallel, every is recommended the isolation of forward mode high frequency and hands over the direct transform ware to include alternating current input unit, input filter, converting?unit is just swashed to isolated the recommending of high frequency, cycloconverter, output filter and output interflow capacitive load. The utility model discloses only use traditional reactive compensation capacitor, whole device price is cheaper, can realize simultaneously the electric isolation of compensating capacitor and electric wire netting side, the reliability is higher, and change the high -frequency transformer transformation ratio, the compensation capacity of whole device has bigger autonomic selectivity under the same electric pressure and compensating capacitor's the objective condition.