A Hybrid Cascade Asymmetrical Multilevel Converter with Isolated Voltage Source

In this paper, a hybrid cascade asymmetrical multilevel converter is proposed. The converter is based on connection of multiple single-phase asymmetrical multilevel converter modules. The multilevel waveform is synthesized by addition or of the voltages generated by the different cells. The primary advantage of the converter is that the number of voltage levels can be increased for a given number of devices. However the converter requires fixed isolated supplies and therefore transformer/rectifier circuits may be used to supply the sources by adjusting transformer ratio according to the needs of the converter. Selective harmonic elimination method is used to eliminate the specified harmonics in the output voltage. Experimental results are presented to verify the proposed method.