Design and Implementation of a Current-Controlled Parallel Hybrid Power Filter

This paper deals with the implementation of an indirect current control of a parallel hybrid filter (PHF) system 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 (PFs) under unbalanced situations that are existing in the PFs under fault conditions. Moreover, due to a limited capacity of voltage source inverter, an upper limit for such compensation may be imposed by the proposed indirect current control based on synchronous reference frame employing decomposition of current in synchronously rotating reference frame that 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 for developed prototype of the PHF. PFs are developed keeping in view its operation with the PHF, so that the total harmonic distortion 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, which optimizes the solution for multiple constraints. The operation of the PHF under dynamic change of load is also investigated through simulations under MATLAB and through experimentation.