Switched-Capacitor Multilevel Inverter With Input Source-Load Common Ground for Applications Supplied by Green Energy
Zeyv Zhang, Jia Yao, Adrian Ioinovici
Abstract
A new switched-capacitor-based multilevel inverter is proposed. It can boost the low and unstable voltage of the solar cells to a large and controllable ac voltage, as required by many standalone consumers or by the electrical grid. It features a high energy processing efficiency as all its switches are submitted to a voltage stress equal to the low input voltage. No output bridge whose transistors would be submitted to the high load voltage is required. A structure with a common ground between the energy cell and the load is created. Thus, the typical leakage current of a solar cell is suppressed. The new circuit is favorably compared with available solutions. The operation of the multilevel inverter is explained for a particular case with 7 levels; the circuit is generalized to a ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2{n}+$ </tex-math></inline-formula> 1) levels one. A 7-levels 484 W power inverter supplied by solar cell is designed and implemented in the laboratory, showing the highest efficiency of 98.43%, and of 96.4% at full-load. A total harmonic distortion (THD) of the output waveform is measured as 23.7%.