Summary: | Increasing the specific power and efficiency of a power converter has been the forever-lasting task for power electronics engineers. With the Wide bandgap (WBG) semiconductor devices, new opportunities and challenges have been found. In this article, a 100-kW SiC grid-connected Photovoltaic (PV) string inverter is proposed. This SiC inverter is free of a grid interface filter, the size, weight, and cost of magnetic components are therefore reduced. In addition, to further achieve high power density high efficiency at 100kW, design aspects including closed-form equation to avoid overdesign passive components, ICT design optimization, and interphase crosstalk mitigation with high switching frequency have been presented. A 100-kW three-phase two-stage prototype has been built in the laboratory, which achieves a specific power of 5 kW/kg, measured peak efficiency of 99.5%, and California Energy Commission (CEC) efficiency of 99.2%.
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