Three-phase rectifiers with suboptimal current injection and improved efficiency

Three-phase diode bridge rectifiers that apply suboptimal current injection and active resistance emulation are analysed. Two types of current injection devices (CIDs) are in the focus, and rectifiers with each CID are analysed for two cases of active resistance emulation: one that applies low-frequency filtering of the emulator output, and another that does not. Models that cover both continuous and discontinuous conduction mode are developed. To minimise the input current total harmonic distortion (THD), optimisation is performed, showing that in each case the THD is about the same when the emulated resistance takes its optimal value. The results are experimentally verified on a 1.5 kW rectifier.