Combined rectifying system including double-series capacitor-smoothed diode rectifier and series active filter

This paper proposes a new rectifying system consisting of a series active filter and a double-series three-phase 12-pulse diode rectifier. The supply current in the proposed system has a sinusoidal wave shape because the series active filter suppresses the current harmonics produced by the diode rectifier. Since almost no 5th and 7th harmonics are produced by the double-series 12-pulse diode rectifier, the required peak rating of the series active filter is only 7% of the diode rectifier. In this paper, the control scheme and operating characteristics of the series active filter are theoretically and experimentally discussed. A novel conception that connection of a parallel capacitor to each diode of the rectifier makes a great contribution to reducing the required rating of the series active filter is also presented and verified by some experimental results. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(1): 85–94, 1997