Combined H-bridge cells cascaded transformers multilevel inverter

A single source less component structure of cascaded transformer H-bridge inverter is proposed in this paper. Depend on desired output voltage waveform; suggested topology consists of several basic cells. Each basic cell includes six unidirectional switches and two low frequency single phase insulated transformers. All cells are feed from same dc source. To produce desired voltage waveform, output of cells is connected in series. The proposed inverter configuration reduces number of switches compared to both traditional cascaded transformer H- bridge multilevel inverter and cascaded H-bridge multilevel inverter and this reduction in turn causes to reduction of cost, volume, energy losing and complexity and increase reliability of system. Transformer ratio at each cell can be chosen as symmetric and asymmetric. In symmetric state number of output voltage steps are low, instead switching stress over switches and switches current rating is low as well. Versus about asymmetric state, however current rating of switches and switching stress over component are high instead output voltage has more steps and less THD. Reduction of DC sources and high modularity are the other advantages of suggested topology. To verify validity of proposed structure, theoretical analysis and simulation results (using MATLAB/SIMULINK environment) are exhibited in this paper.