A Wide-Voltage-Range Input High-Power-Density Three-Phase Grid-Frequency Isolated Inverter

As shipboard distribution systems keep advancing toward miniaturization, integration, and high efficiency, energy storage components have become an integral part of the distribution system. Three-phase inverters are confronted with challenges including a broad DC input voltage range, stringent AC power quality standards, and the demand for high power density. This study presents a hybrid three-phase dual-stage inverter topology that markedly enhances the equivalent switching frequency via multiphase technology, realizing a five-level phase voltage with a fourfold frequency gain and thus lowering the requirement for LC filters. The adoption of a carrier phase-shifting (CPS) modulation scheme effectively suppresses the output common-mode (CM) voltage, thus significantly reducing the design requirements for EMI filters. Through the application of integrated transformer magnetic circuit technology and a three-dimensional (3D) coiled core structure, the overall size and weight of isolation transformers and filter inductors have been significantly reduced. Moreover, the series connection of the transformer's secondary windings enhances the peak amplitude of the AC output voltage while further improving the utilization efficiency of the DC voltage. Through these comprehensive measures, the designed distribution system inverter exhibits the advantages of high system efficiency, strong reliability, cost-effectiveness, compact size, and light weight, making it particularly suitable for high-power applications requiring isolated wide-range DC voltage inputs.