Compensation characteristics of the combined system of shunt passive and series active filters

A combined system of shunt passive and small rated series active filters has already been proposed by the authors. The operating principle and steady compensation characteristics have been presented as well. The combined system can greatly reduce problems of using only shunt passive or shunt active filters and is suitable for harmonic compensation for large VA rated loads in power systems because the required VA rating of the series active filter used is considerably smaller than that of a conventional shunt active power filter.In this paper, transient compensation characteristics and stability of the system are discussed and analyzed theoretically and experimentally in detail. A new control method, which enables application of the combined system to compensation for cyclo converters, is proposed. Some results obtained from the experimental model using the new control method are presented to demonstrate and confirm its validity.