CURRENT-TYPE ACTIVE FILTER FOR POWER DISTRIBUTION

摘要

PURPOSE:To output a compensation current and at the same time increase the frequency of a sideband wave and simplify a filter for eliminating the sideband wave by comparing the tooth-shaped wave of the carrier of pulse wave modulation and a barrier current waveform on the basis of the calculation by a compensation current generation means and turning on or off a switching element. CONSTITUTION:A load 2 is connected to a three-phase power distribution wire 1 and an active filter 3 is connected in parallel with the load 2. The active filter 3 includes a barrier current detector 4 for detecting barrier current and a compensation current generator 5 for generating compensation current. The tooth-shaped wave of the carrier of pulse width modulation is dimensionally compared with a barrier current waveform on the basis of the calculation of the barrier current by the compensation current generator 5, thus turning on or off the switching element. Then, a sideband wave cause by the pulse width modulation is eliminated by an LC filter 6, thus increasing the frequency of the sideband wave, simplifying the filter 6 for eliminating the sideband wave, and drastically improving performance.