Power Quality Enhancement Using Current Injection Technique in a Zigzag Configured Autotransformer-Based 12-Pulse Rectifier

This paper proposes a DC-side circuit configuration that improves the harmonic suppression ability of a 12-pulse diode bridge rectifier (DBR) using a zigzag configured autotransformer. The DC-side circuit uses a single-phase DBR along with interphase transformer which generates the required circulating current thereby modifies the DC currents at the DBR output, in turn shapes the input line current near to a sine wave. The proposed single-phase DBR is connected in parallel with the load which enables to reuse the harmonic energy thus improving the energy conversion efficiency. The zigzag configured autotransformer used for 12-pulse DBR possesses the inbuilt ability to hinder the zero-sequence components, which expel the need of zero sequence blocking transformer. The proposed configuration is analyzed, simulated in MATLAB Simulink and the simulation results are presented, which confirm the reduction of total harmonic distortion (THD) in the input line current thereby improving the power quality under large load variations. Furthermore, the viability of the proposed configuration is verified by experimental results, which confirm the suitability of the proposed configuration in industrial applications.