PCB-Based 1.2 kV SiC MOSFET Packages for High Power Density Electric Vehicle On-Board Chargers

Abstract

Global energy consumption continues to grow, driving the need for cheap, power-dense power electronics. Replacing the incumbent silicon insulated gate bipolar transistors with silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs) has been proposed as a solution to increase the power densities of power converters in some applications. One such application is electric vehicles (EVs) where the efficiency and weight of the power electronics are critical; however, modern packaging technologies are still limiting the performance of SiC MOSFETs. One promising trend in power semiconductor packaging technologies is the use of printed circuit boards (PCBs) because the technology is mature—resulting in low costs—and the allowable stackups are ideal for integrating driving circuitry and power loop components—resulting in reduced manufacturing complexity. This thesis presents the design and analysis of two PCB-embedded 1.2 kV SiC MOSFET half-bridge packages and a hybrid PCB/DBC-based 1.2 kV SiC MOSFET full-bridge package for EV on-board charger applications. The first of the two PCB-embedded packages has integrated gate drive circuitry, less than 2.3 nH loop inductances, and dual-sided cooling with a total junction-to-case thermal resistance (RTH,JC) of 0.12 K/W. The second PCB-embedded package has only drain-side cooling to allow for surface mount terminals, has an area of 37.1 mm x 18.5 mm due to the removal of the gate drive circuitry, and has less than 2.4 nH loop inductances. The PCB/DBC-based full-bridge package has an RTH,JC of 0.65 K/W, less than 4.5 nH, and integrated gate drive circuitry.