Design and Implementation of a Current Controlled Parallel Hybrid Power Filter

This paper deals with the implementation of an indirect current control of parallel hybrid filter system (PHF) with rectifier load to eliminate generated harmonics. The compensation principle, design and PHF implementation are discussed in detail. The proposed control enhances the performance of the passive filters under unbalance situations existing in the passive filters under fault conditions. Moreover, due to limited capacity of VSI a upper limit for such compensation may be imposed by proposed indirect current control based on synchronous reference frame employing decomposition of current in synchronously rotating reference frame (SRF) is used to control PHF. The PHF is controlled using decomposition of load and source currents. The implementation of the control scheme is carried out on dSpace with digital signal processor (DSP) for developed prototype of PHF. Passive filters are developed keeping in view of its operation with PHF, so that, the total harmonic distortion (THD) in the source current gets minimized along with minimized fundamental frequency current sinking through the filter section. The design has been carried out by genetic algorithm (GA), which optimizes the solution for multiple constraints. Operation of PHF under dynamic change of load is also investigated through simulations under MATLAB and through experimentation.