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A 1200 V, 60 A SiC MOSFET Multi-Chip Phase-Leg Module for High-Temperature, High-Frequency Applications

Fig. 1. SiC MOSFET phase-leg module.
The requirement of high power density for today's power converters is continuously pushing the Si devices to their limits, in both the operating temperature and switching frequency. In many applications, the newly commercialized SiC devices have become the ideal choice for substitute.

In this work, commercial SiC MOSFETs are used to build a 1200 V, 60 A phase-leg module for high-temperature operation. Three 1200 V, 20 A SiC MOSFETs and three 1200 V, 10 A SiC Schottky diodes are paralleled in each switch position to reach the rated current. The power module is designed and fabricated with all high-temperature packaging materials. In order to reduce the package parasitics, an improved substrate layout based on the "switch pair" concept is adopted to minimize the main switching loop inductance, which is critical in causing the switching transient ringing. The switching performance is further improved by embedding DC decoupling capacitors inside the module, which helps to decouple the parasitics from the module's busbar (Fig. 1). With this design, the SiC power module can achieve much faster switching speed than conventional Si IGBT modules without suffering from serious parasitic ringing. Continuous test successfully verifies the high-temperature and high-frequency operation of the module by running the devices at 200°C and 100 kHz (Fig. 2).

Fig. 2. (a) Buck-mode test of the module at 200°C and 100 kHz: Experimental waveforms.
Fig. 2. (b) Thermograph picture showing the temperature distribution.
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