A Common Ground Switched-Capacitor Multilevel Inverter With a Low Component Count
Jia Yao, Zeyv Zhang, Xiaofeng Zheng, Adrian Ioinovici
Abstract
A new dc–ac inverter suitable for electrical systems powered by photovoltaics is developed for applications like aircrafts, drones, or satellites. The proposed modular input source-load common ground 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 micro electric grid. The circuit is proposed for a general number of levels. Then, a particular case is considered: an inverter providing a 9-levels output waveform. It is analyzed, designed and implemented in the laboratory. The measured efficiency of the designed SCMLI at the nominal 500W power is 96.6%.