A Highly-Integrated SiC Power Module for Fast Switching DC-DC Converters

摘要

This paper addresses design elements of highly-integrated silicon carbide power modules allowing fast switching transients and, consequently, elevated PWM frequencies for dc-dc converters with high power densities. However, a minimal stray inductance is crucial for applications at high PWM frequencies. It is realized in this work using two key features: an electrical layout is proposed that creates an optimized commutation loop with minimized self-inductance on the basis of direct-bonded copper substrates. Furthermore, the dc-link capacitor is integrated onto the substrate such that typical connection elements are eliminated. The electrical design is verified with double-pulse measurements. To realize a high power density, the power module is cooled by an integrated micro-channel cooling structure. The cooling structure enables heat dissipation that most state-of-the-art power converters achieve only with double-sided cooling techniques. The addressed design elements are combined with an optimized inductor resulting in a synchronous boost dc-dc converter operated at a switching frequency of 333 kHz. Experimental results show that a maximum efficiency of 98.12 % at a maximum output power of 23.4 kW is achieved. This results in a power density of 70.9 kW/(dm~3).