Study of a High-Efficient Wide-Bandgap DC-DC Power Converter for Solar Power Integration

This research focuses on the design and analysis of a Boost cascaded Buck-Boost (BoCBB) power converter with super high efficiency in electric power conversion. The BoCBB power converter is based on emerging wide-bandgap silicon-carbide (SiC) MOSFETs and Schottky diodes, which have only 1/6 times of power loss in traditional silicon power semiconductor devices. The BoCBB power converter can be widely applied in solar harvesting for the National Aeronautics and Space Administration (NASA), military bases and electric utilities, as well as high-power DC motor drives for the electric vehicles, robotics, and manufacturing and product lines. This research analyzed the topology and energy efficiency of a 3-kW BoCBB power converter. The energy efficiency of the SiC-based BoCBB power converter was calculated under various switching frequencies (20-kHz – 100-kHz) and was first tested by a simulation study of solar power integration in a 400-Vdc distribution microgrid in Matlab/Simulink environment. The design of 50-kHz in switching frequency revealed to be optimal in overall system performance. This conclusion was further verified by experimental tests. The experimental tests demonstrated a high efficiency of above 97% in power conversion. In order to improve the power quality of the BoCBB power converter for time-varying solar radiation, a novel sliding-window-combined (SWC) hysteresis control technique was proposed and preliminarily verified by a simulation study to enhance transients of a power grid