Switching-Cell Back-to-Back Current Source Converter with Modified SVPWM

Current source back-to-back converter has some advantage than voltage source back-to-back converter such as using inductor for power decoupling, no shoot-through problem. However, open-circuit problem occurs when there is no path for the inductor current to flow. Therefore, conventional current source rectifier or inverter needs overlap time to prevent open-circuit problem. The overlap time distort waveform of the output current. This study proposed a three-phase switching-cell back-to-back current source converter (SC-CSC). Compared to the conventional current source converter, the SC-CSC has no open-circuit possibility; thus, the converter reliability is greatly enhanced. However, due to the presence of switching-cell capacitors, SVPWM is modified in order to make voltage rating of semiconductor device the same as conventional one. The operating principle and characteristics of the proposed SC-CSC are analyzed in detail.