An Effective Structure of Three-Phase Parallel Hybrid Active Power Filter to Accurate Harmonic Elimination

In this paper, a proposed structure of a parallel hybrid power filter is introduced which is appropriate for group elimination of current harmonics as well as reactive power compensation in medium or low voltage power grids. According to the common structures of parallel hybrid filters, the proposed structures include a series resonance circuit with a small inductance in parallel with the active power filter. In other words, the passive filter design is a hybrid structure in which the majority of the main reactive current passes through additional inductance instead of passing through the active power filter, which reduces the current flowing through the switching equipment of the power converter. Also, due to the special design of the passive filter in this proposed structure, the active power filter does not need to withstand the harmonic voltage. Therefore, the result and advantage of these features is that the volt-ampere of the active power filter is significantly reduced. Computer simulation results indicate strong application of the proposed parallel HAPF to harmonics exclusion and reactive power compensation.