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Emerging wide-bandgap (WBG) semiconductor devices such as silicon carbide (SiC) metal–oxide semiconductor field-effect transistors (MOSFETs) and gallium nitride high-electron-mobility transistors can handle high power in reduced semiconductor areas better than conventional Si-based devices owing to superior material properties. With increased power loss density in a WBG-based converter and reduced die size in power modules, thermal management of power devices must be optimized for high performance. This article presents a graphite-embedded insulated metal substrate (thermally-annealed-pyrolytic-graphite-embedded insulated metal substrate—IMSwTPG) designed for WBG power modules. Theoretical thermal performance analysis of graphite-embedded metal cores is presented, with design details for IMSwTPG with embedded graphite to replace a direct-bonded copper (DBC) substrate. The proposed IMSwTPG is compared with an aluminum nitride-based DBC substrate using finite-element thermal analysis for steady-state and transient thermal performance. The solutions’ thermal performances are compared under different coolant temperature and thermal loading conditions, and the proposed substrate's electrical performance is validated with static and dynamic characterization. Using graphite-embedded substrates, junction-to-case thermal resistance of SiC MOSFETs can be reduced up to 17%, and device current density can be increased by 10%, regardless of the thermal management strategy used to cool the substrate. Reduced transient thermal impedance of up to 40% of dies owing to increased heat capacity is validated in transient thermal simulations and experiments. The half-bridge power module's electrical performance is evaluated for on-state resistance, switching performance, and switching loss at three junction temperature conditions. The proposed substrate solution has minimal impact on conduction and switching performance of SiC MOSFETs. [ABSTRACT FROM AUTHOR]

This article presents a systematic power stage design approach for a high-power density air-cooled inverter, which involves the utilization of emerging 1.7 kV silicon carbide (SiC) mosfet bare die engineering samples, heatsinks optimized with genetic algorithm, and built using three-dimensional printing technology and integrated power modules with a novel packaging structure. The developed air-cooled inverter assembly is mainly composed of the SiC mosfet phase leg modules with split high-side and low-side switch submodules, which are attached to two separate heatsinks for increased heat dissipation area and reduced thermal resistance. The heatsink is designed using a co-simulation environment with finite element analysis in COMSOL and genetic algorithm in MATLAB. The primary design procedure, including bare die device characterization, loss calculation, thermal evaluation, and power module development, is elaborated. The proposed design approach is verified and validated through experiments at each stage of development. The experimental results show that the inverter California Energy Commission efficiency is 98.4%, and a power density of 75 W/in3 is achieved with a sufficient junction temperature margin for semiconductor long-term reliability. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper. [ABSTRACT FROM AUTHOR]

The application of silicon carbide (SiC) devices as battery interface, motor controller, etc., in a hybrid electric vehicle (HEV) will be beneficial due to their high-temperature capability, high-power density, and high efficiency. Moreover, the light weight and small volume will affect the whole powertrain system in a HEV and, thus, the performance and cost. In this paper, the performance of HEVs is analyzed using the vehicle simulation software Powertrain System Analysis Toolkit (PSAT). Power loss models of a SiC inverter based on the test results of latest SiC devices are incorporated into PSAT powertrain models in order to study the impact of SiC devices on HEVs from a system standpoint and give a direct correlation between the inverter efficiency and weight and the vehicle's fuel economy. Two types of HEVs are considered. One is the 2004 Toyota Prius HEV, and the other is a plug-in HEV (PHEV), whose powertrain architecture is the same as that of the 2004 Toyota Prius HEV. The vehicle-level benefits from the introduction of SiC devices are demonstrated by simulations. Not only the power loss in the motor controller but also those in other components in the vehicle powertrain are reduced. As a result, the system efficiency is improved, and vehicles that incorporate SiC power electronics are predicted to consume less energy and have lower emissions and improved system compactness with a simplified thermal management system. For the PHEV, the benefits are even more distinct; in particular, the size of the battery bank can be reduced for optimum design. [ABSTRACT FROM PUBLISHER]

Silicon carbide (SiC) power devices are expected to have an impact on power converter efficiency, weight, volume, and reliability. Currently, only SiC Schottky diodes are commercially available at relatively low current ratings. Oak Ridge National Laboratory. has collaborated with Cree and Semikron to build a Si insulated-gate bipolar transistor-SiC Schottky diode hybrid 55-kW inverter by replacing the Si p-n diodes in Semikron's automotive inverter with Cree's made-to-order higher current SiC Schottky diodes. This paper presents the developed models of these diodes for circuit simulators, shows inverter test results, and compares the results with those of a similar all-Si inverter. [ABSTRACT FROM AUTHOR]