ECE – 590 I POWER & ENERGY SYSTEMS SEMINAR
WHEN: Monday, April 8, 2024, 3:00 – 3:50 p.m.
WHERE: ECEB 4070
SPEAKER: Zhuoran Han, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign
TITLE: "Diamond Power Electronics for Next Generation Power Grid"
ABSTRACT: This presentation delves into the potential of diamond as an ultrawide-bandgap semiconductor in revolutionizing power devices for the future electric grid. Diamond's exceptional properties, including its large bandgap (5.47 eV), high critical electric field (10 – 20 MV/cm), high carrier mobility (up to 2100 cm²/V/s), and superior thermal conductivity (22 - 24 W/cm/K), position it as a material capable of outperforming current-generation devices. The research presented herein explores diamond power devices, leveraging these superior material properties for next-generation grid applications. It encompasses the development of essential fabrication and processing techniques, including the formation of ohmic and Schottky contacts. Experimental demonstration of high breakdown voltage (> 4.6 kV) diamond Schottky barrier diodes (SBDs) and prototype reverse-blocking metal-semiconductor field-effect transistors (RB-MESFETs) are presented. Furthermore, it proposes innovative diamond buried channel semiconductor photoconductive switches (PCSS). These PCSS are fabricated and characterized, demonstrating fast rise/fall times (approximately nanoseconds) and high current density (> 43.5 A/cm²), making them suitable for applications in grid protection and resilience.
SPEAKER: Anuj Maheshwari, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign
TITLE: "Control Architecture for Full-Bridge LLC Series Resonant Converters Using Output Diode Current"
ABSTRACT: The controller design for the LLC resonant dc-dc converter is challenging due to the large number of poles whose locations vary with operating conditions. A controller's ability to reject input disturbance is required to reduce the input filter size and increase power density. We present a control architecture utilizing the output diode current measurement that reduces the control-to-output transfer function for an LLC resonant converter to first order and provides a high degree of input voltage disturbance rejection with a minimal increase in control-loop complexity. Loop analysis using small signal model and Bode plot highlights the advantages of the proposed method. Simulated and experimental results highlighting the proposed architecture's high disturbance rejection capabilities are shown. Experimental setup is built with power factor correction rectifier as the front-end stage with LLC resonant converter as the dc-dc converter. The proposed approach achieves more than 2 times reduction in output voltage ripple using 66% less capacitance at the dc-link compared to direct frequency control in experiments.
