[Back]

H. Ertl, J.W. Kolar, F. Zach:
"A Novel Multi-Cell DC-AC Converter for Applications in Renewable Energy Systems";
Poster: International Conference on Power Conversion and Intelligent Motion (PCIM), Nürnberg, Deutschland (invited); 2001-06-19 - 2001-06-21; in: "Proceedings", Proc. of the 43rd Int.Conf. on Power Conversion (2001), 579 - 586.

Abstract - The paper presents a novel DC-AC converter for applications especially in the area of distributed energy generation systems, e.g., solar power systems, fuel-cell power systems in combination with super-capacitor or battery energy storage. The proposed converter is realized using an isolated multi-cell topology where the total AC output of the system is formed by series connection of several H-bridge inverter stages. The DC links of the H-bridges are supplied by individual DC-DC isolation stages which are arranged in parallel concerning the DC input of the total system. Therefore, all switching cells of the proposed converter can be equipped with modern low-voltage high-current power MOSFETs which results in an improved efficiency as compared to conventional isolated DC-AC converters. Furthermore, the cells are operated in an interleaved PWM mode which in connection with the low voltage level of each cell significantly reduces the filtering effort on the AC output of the overall system. The paper describes the operating principle, analyzes the fundamental relationships being relevant for component selection and presents a specific circuit design. Finally, measurements taken from a 2kW laboratory model are presented.