A novel three-phase full bridge thyristor rectifier based on the controlled third harmonic current injection

A novel three-phase full bridge thyristor rectifier that applies controlled third harmonic current injection is described in this paper. To compensate for the variations in the bridge firing angle and the rectifier load current, the concept of resistor-free current injection network is adapted applying controlled current injection method. This approach makes it possible to obtain near optimal current injection resulting in minimum input current THD, while preserving high efficiency of the rectifier. Optimization of the injected current is attained through the time domain analysis, on the waveform level. Based on this analysis the selection of current injection network parameters is made. Feasibility of the proposed concept is verified both experimentally and by simulation.