Symmetrical hybrid multilevel inverter concept based on multi-state switching cells

This paper presents a novel symmetrical hybrid multilevel inverter for applications aiming at high power densities and high resolution of the output voltages. This proposal is the connection of a given number N of switching three levels cells consisting of semiconductor devices connected in parallel through multi-interphase transformers. This arrangement provides a balanced distribution of currents, thus, increasing the power density and providing an output voltage with high number of voltage levels. Therefore, the harmonic contents of the voltages applied to a given load are small. The achieved output voltages are analyzed by means of the Fourier series for a given number N of cells connected in parallel. Simulation results illustrate the operational principles of the proposed converter concept.