CAREER: A Universal Block of "Series Connected SiC MOSFET" for Medium/High voltage converter

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CAREER: A Universal Block of Series-Parallel Connected SiC MOSFETs for High Voltage High Power Conversion System Power electronic systems are widely developed nowadays in electrical vehicles, renewable energy, data center, medical equipment, lighting, and other industrial or consumer applications. The systems in these applications need to shrink system components and achieve light weight and high efficiency simultaneously. These goals of power electronic systems can be accomplished by multiple improvements of power modules such as lower loss, higher frequency, higher temperature and downsizing. In order to make breakthrough in these demands for power modules, it is important to replace the device material from Silicon (Si) to the next generation ones such as Silicon-Carbon (SiC) or Gallium Nitride (GaN). Although the low voltage SiC power device is expected to replace the Silicon device with the rapid increase of market adoption of SiC technology, Silicon device are still dominant in high-voltage high-power applications. The goal of this research is to develop the high voltage high current SiC module based on the existing commercially available device technology to enable the use of SiC-based semiconductors in the high-voltage high-power conversion systems. System benefits such as improved efficiency, reduced part count along with reduced size and weight should make this technology attractive for adoption in these applications. The comprehensive nature of this project will also support a multi-faceted program of research training, with impact at both the graduate and undergraduate levels. The outcome of this project will be disseminated through the undergraduate and graduate courses to prepare the students for future careers. The goal of this CAREER project is to significantly improve the efficiency and power density of high-voltage high-power conversion systems. To achieve the goal, the proposed approach is to replace the high voltage Si IGBT (3.3kV, 4.5kV, 6.5kV) by series and parallel connected low voltage SiC MOSFETs (1.2kV, 1.7kV). Specifically, a game changing and universally applicable standard block of "series-parallel connected SiC MOSFET" will be developed with excellent dynamic voltage/current sharing and high reliability. In order to reach this objective, it is worth noting that the series-parallel connections of multiple devices have the following design challenges that must be addressed: unequal static and dynamic voltage/current sharing which is normally due to the part-to-part device parameter variations, the gate loop parasitic differences, the gate resistor tolerance, the isolation level differences and the signal transmission channel to channel delays; immunity to the conventional de-saturation protection for short-circuit failure; excessive voltage ringing due to the additional loop inductance contributed by the connected bus bars between devices. The advanced methods are proposed to be integrated into the block to overcome these challenges. The feasibility and advantages of the standard block will be demonstrated in the power-down-scaled medium voltage drive, medium voltage PV power conversion, Extreme Fast Charging (XFC) station medium voltage power conversion prototypes. Except for that, the technology will be applied to GaN device to form high voltage high current GaN module competing with the single SiC MOSFET as well and the efficiency/density benefits will be demonstrated.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.