A Common Ground Switched-Capacitor Multilevel Inverter With a Low Component Count

A new dc-ac inverter suitable for electrical systems powered by photovoltaics has been developed for applications, such as aircraft, drones, or satellites. The proposed modular input source-load common ground switched-capacitor multilevel inverter (SCMLI) minimizes the number of switches and capacitors, which are necessary for getting the desired number of levels in the staircase output waveform. The penalty is an increased voltage stress on a few switches, but this affects the efficiency in a negligible way. The inverter is purposely designed for systems using photovoltaics as the energy source. The common ground eliminates the leakage current of the solar cells, which is a cause of energy losses and distortion of the output waveform. The inverter can supply either a standalone load or a microelectric grid. The circuit is proposed for a general number of levels. Then, a particular case is considered: an inverter providing a nine-level output waveform. It is analyzed, designed, and implemented in the laboratory. The measured efficiency of the designed SCMLI at the nominal 500 W power is 96.6%.