A new low cost cascaded transformer multilevel inverter topology using minimum number of components with modified selective harmonic elimination modulation

AbstractIn this paper, a novel cascaded transformer multilevel inverter is proposed. The number of the switching devices is reduced in the proposed topology. This topology comprises of a DC source, several single phase low-frequency transformers, two main power switches and some bidirectional switching devices. In this topology, only one bidirectional switch is employed for each transformer. However, in conventional cascaded transformer multilevel inverter, four switching devices are required for each transformer. Therefore, more output voltage levels can be obtained using fewer switching components. Reduction in the number of switching devices which also means reduction in the number of gate drivers results in smaller size and low implementation cost. Switching power losses are also reduced in this topology. Selective harmonic elimination (SHE) technique is applied to the proposed inverter to obtain a high quality output voltage. Simulation and experimental results are also provided to verify the feasibility of the proposed converter