A 50 kW SiC Three Phase AC DC Converter Design for 200 degree C Ambient Temperature
This work seeks to demonstrate the feasibility of developing a complete high-temperature, high-power-density, 50-kW bidirectional three-phase AC-DC power converter unit for operation in 200 °C environments. The unit, which utilizes SiC power modules, will enable high power generation, increased efficiency, and compact size suitable for aircraft power generation applications. Fig. 1 illustrates the functional characteristics of the unit. This endeavor required the development of high-temperature packaging for both active and passive devices, cooling techniques, and EMI tolerant capability.
One of the core contributions of this work was the design and development of a completely high-temperature (200 °C), high-power (1200 V, 100 A), phase-leg power module utilizing SiC MOSFETs and SiC Schottky diodes. The power module was fabricated, fully characterized, and tested up to 200 °C.
The system-level work includes the integration of the high-temperature power modules, gate drivers, sensors, and protection. In the design and implementation of this system, issues related to noise coupling, including noise generation, noise mitigation, and fault protection, needed to be addressed in order to help in designing a more reliable 200 °C converter. This was achieved by utilizing an improved busbar design and power module structure, implementing chokes and shields, and introducing redundancy protection.
Double-pulse tests (DPTs) were performed on the final high-temperature, 50-kW unit. Fig. 2 shows the constructed unit in the 200 °C environment. The DPTs, conducted at 200 °C ambient, 100 A, and 540 V, revealed good performance of the unit at high-temperature, even after soaking for more than an hour.