Thermal Performance Evaluation of a 1.7-kV, 450-A SiC-MOSFET Based Modular Three-Phase Power Block With Wide Fundamental Frequency Operations

To accelerate wide industry adoption of Silicon Carbide (SiC) based technology, a three-phase two-level inverter based power block is designed with the latest generation high performance 1.7 kV/450 A SiC-MOSFET module from General Electric. The designed power block is expected to replace the currently standardized 1.7 kV/450 A Silicon (Si) insulated gate bipolar transistor (IGBT) based three-phase power block. Power converters face thermal challenges when subjected to very low fundamental frequency operations (below 10 Hz). This is particularly relevant in the wind power applications. At low operating fundamental frequencies, the junction temperature of the power device experiences high peak-to-peak ripple, which degrades the reliability of the power modules significantly. This paper presents the thermal performance of the designed power block and draws comparisons with a similar rated Si-IGBT module based power blocks, especially at low output fundamental frequency operations. Key performance indices, including power rating curves at different switching frequencies and power factors; temperature ripple at different fundamental frequencies, are examined. Simulation and experimental results are provided to validate the claims. The results indicate that the SiC-MOSFET module based power block can be a promising replacement for the Si-IGBT based power block especially in applications where wide range of fundamental frequency operations are needed.