A Single-Stage Converter for Integration of Induction Wind Energy Conversion Systems into Multilevel Stand-Alone DC Nanogrids

Multilevel DC nanogrids (DC-NGs) are a viable solution for small-scale stand-alone energy systems, especially in remote areas. They can be powered by wind energy cheaply and safely and thus increase the availably of energy in areas with limited solar irradiance. Among different options for energy conversion, induction machines can be used as generators for wind energy conversion as they are low-cost, reliable, and almost maintenance-free, but the cost and complexity of power electronic converters have limited this approach to low-power applications. This paper proposes a compact single-stage converter that has only six switches, can provide all the control functions for a self-excited induction generator (SEIG), and can interface the SEIG to two isolated DC systems. Moreover, the converter can integrate a small backup battery for the black-start of the SEIG. In this paper, the converter's feasibility is confirmed with experimental results from a scaled-down prototype converter, and the overall performance of the wind energy conversion system is studied in MATLAB/Simulink.