Ultra-wide-input Voltage Range Auxiliary Power Supply using 3.3 kV SiC MOSFETS
Applications utilizing high input voltage are gradually increasing, and hence a high-step-down ratio power supply has recently begun being included in applications such as modular multilevel converters (MMCs) and 1.5 kV photovoltaic (PV) inverters. However, due to the high electric field imposed on the switching devices, it is challenging for power converter designers to develop a converter that can ensure both safety and reliability. This paper provides the study of several options and comparisons to design a wide-input-range (up to 6 kV), high-step-down ratio converter that provides a regulated 48 V at the output. The design of a flyback-based power supply that incorporates a single 3.3 kV, 30 A discrete device is presented. Moreover, this paper introduces the design of a medium-voltage insulated transformer for such power supplies.