Event
Ph.D. Research Proposal Exam: Gamwari Ayodhya Kinkini Somiruwan
Monday, September 22, 2025
11:00 a.m.
Souad Nejjar
301 405 8135
snejjar@umd.edu
ANNOUNCEMENT: Ph.D. Research Proposal Exam
Committee:
Professor Alireza Khaligh (Chair)
Professor Xin Zan
Professor Sahil Shah
Date/time: Monday, September 22, 2025 at 11:00 AM
Title: A LOW-INDUCTANCE SIC BARE-DIE HALF-BRIDGE POWER MODULE FOR TRACTION INVERTER APPLICATIONS
Abstract:
Global environmental and climate concerns are accelerating the shift toward sustainable technologies, with electric vehicles (EVs) playing a central role. The rapid growth of both passenger and commercial EVs is driving the demand for high-power traction motors, which in turn requires inverter systems that are both highly reliable and power-dense. Traditionally, traction inverters employ packaged power devices such as TO-247. These packages inherently include lead inductance from internal wire-bonding and present significant thermal resistance from the device junction to the case. Their size also constrains PCB layout, preventing close placement of devices and increasing stray inductance in current paths. The resulting large commutation loop inductance causes higher voltage overshoot, increased switching losses, and reduced device reliability. To protect the DC link from these stresses, additional bulky capacitors are required, and the combination of higher switching losses and elevated thermal resistance demands larger cooling systems. Therefore, reducing parasitic inductance and implementing improved thermal management are essential for achieving reliable, power-dense traction inverters.
This research proposes a modular, low-parasitic half-bridge power module based on SiC bare-die devices, designed to minimize commutation-loop inductance and support high power density in traction inverter applications. The module incorporates an integrated thermal management component compatible with liquid cooling to sustain high-load operation. Having direct access to the device without a package enables dual side cooling, unlike the single side cooling in TO247 packages. Its modular architecture enables deployment across multiple traction inverter topologies in which half-bridges serve as the fundamental switching unit. The methodology begins with an analysis of the switching transition behavior of SiC MOSFET half-bridges to quantify the influence of commutation-loop inductance on voltage overshoot and switching power loss. The proposed phase-leg module architecture is then evaluated using finite element analysis (FEA) to extract parasitic inductance and optimize the design for minimal loop inductance. A repeatable, step-by-step assembly process will be established to ensure manufacturability and consistency. Finally, the fabricated phase-leg will undergo characterization using standard tests, including the double pulse test (DPT). The proposed module will be validated through integration into an 18 kW, 800 V DC-link, two-level, three-phase traction inverter platform, with electrical performance, thermal behavior, and integration benefits evaluated under representative operating conditions, demonstrating its modularity and application versatility.
