A Method for Reducing Harmonics in Input Current of Double Connected Three-Phase Hybrid Rectifier without Input Transformers

In this paper, a double connected three-phase hybrid rectifier employing thyristors and self-turn-off devices without input transformers is proposed. Two three-phase bridge rectifiers with auxiliary circuit injecting harmonic currents are connected in parallel. This system can be performed as the conventional 24-step rectifier on the optimum conditions. In this paper, circuit performances of the proposed method are discussed by graphical analysis, and optimum parameters are derived. Then, effects on harmonics reduction can be clarified by simulations.