Simplified quasi-Z source indirect matrix converter

Conventional matrix converters have a limited voltage gain less than 0.866 and also require many power switches and additional input filter that ensures a low input current harmonics to the grid. Quasi-Z source (qZS) indirect matrix converter can provide high voltage gain and ensure a sinusoidal input current without additional input filter, which requires 12 power switches in rectifier stage. In this paper, a simplified qZS indirect matrix converter is proposed to overcome aforementioned limitations and achieve (1) higher voltage gain than 0.866, (2) less power switches, and (3) LC-filter function integrated in qZS network to avoid additional filter. The new converter's operating principle and equivalent circuits are analyzed, and the modulation method is presented. The input current closed-loop control is employed to implement sinusoidal input current waveform even though the proposed converter has less power switches and without extra input filter. A test bench is used to verify the simplified qZS indirect matrix converter and control methods. Simulation and experimental results identically validate the proposed converter system with wide voltage gain range and low input current harmonics.