A Si IGBT/SiC MOSFET Hybrid Isolated Bidirectional DC–DC Converter for Reducing Losses and Costs of DC Solid State Transformer

• Published in: Electronics (Basel) Vol. 13; no. 4; p. 801
• Main Authors: Huang, Jun, Wang, Yu, Li, Zhenfeng, Zhu, Hongbo, Li, Kai
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.02.2024
• Subjects: Accuracy; Algorithms; Conduction losses; Cost analysis; Costs; Design and construction; Efficiency; Electric current converters; Electric potential; Electric transformers; Genetic algorithms; Insulated gate bipolar transistors; Lagrange multiplier; Materials; Mathematical optimization; Metal oxide semiconductor field effect transistors; Modulation; Modulation (Electronics); MOSFETs; Optimization; Silicon carbide; Solid state; Switches; Switching; Time domain analysis; Topology; Transformers; Voltage; Voltage converters (DC to DC); China
• ISSN: 2079-9292; 2079-9292
• DOI: 10.3390/electronics13040801

The DC solid state transformer (DCSST) is a crucial component for connecting buses of different voltage levels in the DC distribution grid. This paper proposes a Si IGBT/SiC MOSFET hybrid isolated bidirectional DC–DC converter and an optimized modulation strategy (OMS) to reduce the losses and costs of DCSST. Based on the analysis of topology and operating principles, a duty-cycle modulation strategy is proposed and the converter is modeled by the time domain analysis (TDA) method. Through the analysis of switching characteristics, an optimization problem is established, which aims to reduce the conduction losses of switches while ensuring zero-voltage switching (ZVS) for all switches and low-current turn-off for IGBTs simultaneously. The optimization problem is solved by the augmented Lagrangian genetic algorithm (ALGA), and the OMS for the proposed converter is deduced. Finally, a 2 kW experimental prototype with the primary voltage of 405–495 V and the secondary voltage of 150 V is built to verify the effectiveness of the proposed topology and OMS. The switching costs of the proposed converter is reduced by 27.3% and the efficiency is improved by up to 4.04% compared to the existing method.