Single source self‐balanced switched‐capacitor multilevel inverter with reduced number of semiconductors

Abstract

Recently, the demand for switched-capacitor converters has increased due to the use of a low voltage input source. This article aims to improve some weak points of these inverters, such as the high number of elements by presenting a novel single-source high step-up multi-level inverter topology. The proposed inverter consists of a switched-capacitor cell with self-balancing capability. The proposed converter uses a low voltage DC source to charge a series of capacitors stage by stage to increase the amplitude of the capacitors multiple times the input voltage. These capacitors which work as asymmetrical sources can generate a high-amplitude AC output voltage level and hence reduce the number of DC sources and semiconductors which leads to the simplicity of structure. Since the proposed converter is using low voltage single DC source it can be used in a renewable energy application. Another aspect of this converter is producing negative levels in the output voltage without using a high-voltage full-bridge inverter and reducing the number of components. To verify the proposed multi-level inverter operation, a 9-level prototype is simulated in MATLAB/Simulink and implemented in the laboratory. The simulation and test result of the inverter confirm the validity of the proposed scheme.