High Isolation Auxiliary Power Supply for Medium-Voltage Power Electronics Building Block

The Austin SuperMOS is an intelligent 7.2kV/60A SiC power switch integrated with a gate driver and an isolated auxiliary power supply. Design considerations for the auxiliary power supply in a 5kV Austin SuperMOS based full bridge power electronic building block (PEBB), in terms of electrical performance and insulation against high voltages, are presented in this paper. In the presented auxiliary power supply, an LLC resonant converter along with 4 individual floated voltage sources including high frequency and high-voltage isolation transformers are developed. The design of individual floating sources is based on circuit and FEM simulations as well as necessary engineering calculation. Partial discharge measurements are also conducted to validate the proposed high voltage transformer design. Electrical measurements performed on the fabricated full bridge PEBB reveal stable and proper operation of the system.