Simplified five-level voltage source inverter with level-phaseshifted carriers based modulation technique

A simplified circuit topology of the five-level inverter for DC-AC power conversion with non-insulated DC power sources along with reduced switching device count is introduced and discussed in this research paper. The inverter circuit is based on the three-level H-bridge inverter configuration. The developed five-level PWM inverter needs five controlled power switches and four isolated gate drive circuits. Furthermore, the proposed topology does not require bidirectional power semiconductor controlled switches, hence a conventional discrete power MOSFETs or IGBTs can be used to build the inverter circuits. To achieve a better quality AC output voltage, the level-phase-shifted carriers based sinusoidal pulse width modulation was applied to create a five-level PWM voltage waveform. The developed inverter circuit was examined by utilizing computer simulation with Power PSIM software. The basic principle operation of the inverter circuit was verified experimentally in laboratory applying two noninsulated DC input voltage sources as the inputs of the inverter’s prototype circuit. Some analysis of inverter’s output waveforms are provided and discussed