ECE – 590 I POWER & ENERGY SYSTEMS SEMINAR
WHEN: Monday, April 29, 2024
WHERE: ECEB 4070, 3:00 – 3:50 p.m.
SPEAKER: Soumil Chaubal, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign
TITLE: "Continuously-Variable-Pole Induction Machine Drive for Electric Vehicles"
ABSTRACT: We present an operational methodology or continuous pole sharing in variable pole induction motors (VPIMs) to minimize machine and drive power loss. An optimization problem is formulated to determine torque sharing among poles, revealing that combining two-pole and six-pole components yields minimum losses and enhances magnetic material utilization for a typical machine, particularly at intermediate torque- speed operating points. A modulation method that incorporates common-mode voltage injection is introduced to maximize dc bus utilization. A proposed control architecture enables one pole to operate under vector control and the other under scalar control, thereby reducing parameter dependence for synchronization and reference generation. The proposed approach supports dynamic loss minimization by using the dc bus current and varying the scalar-controlled pole magnitude. Experimental results conducted on a toroidally wound 36-slot machine validate the effectiveness of the proposed approach.
SPEAKER: Jason Paximadas, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign
TITLE: "A Composite Converter Architecture for Wind Energy Systems Connected to AC Grid"
ABSTRACT: A composite converter architecture consisting of a multi-port generator and a set of power electronic converters is proposed for a wind energy system tied to an ac grid. The generated power is delivered to the grid by way of two paths: one via a passive rectifier and line-frequency inverter, and the other through an active rectifier and an inverter operating at switching frequencies higher than their respective fundamental frequencies, with the maximum power processed only 10% of the rated power. The remaining power is processed using the line-frequency path, employing reliable, efficient, and inexpensive diodes and switches. An analytical design framework shows that the high-frequency switch volt-ampere rating can be reduced by 67.9%. This results in an overall loss reduction ranging between 46.8% and 53% depending on the extracted power. Control and modulation strategies and a maximum power point tracking algorithm are presented. Experimental results obtained from a laboratory prototype validate the performance and the effectiveness of the proposed converter architecture, and its control and modulation strategies. This approach opens up opportunities for integrating ac-collection networks through an efficient, reliable, and cost-effective energy conversion system.
SPEAKER: Ethan Williams, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign
"TITLE: "Closed-Loop Control for Heterogeneous Power Systems
ABSTRACT: For power systems, secure operation entails that system voltages are kept within prescribed limits and that frequency is maintained at or near its nominal values. The growing penetration of inverter-based energy sources has challenged this secure operation however, necessitating analysis and study of control schemes for systems with these resources. Conventionally, control has been handled under a hierarchical three-tier structure organized by primary, secondary, and tertiary stages. In this presentation, we present conventional control algorithms for secondary frequency and voltage control of power systems with synchronous generators (SG) and grid-forming inverters (GFM) operating with droop control, virtual synchronous machine control (VSMC), and dispatchable virtual oscillator control (dVOC) for their primary control schemes. Further, we propose a linear-quadratic regulator (LQR) scheme that provides augmented primary and secondary control for frequency and voltage. In addition, this control scheme addresses certain limitations of conventional secondary control such as restricted control action and undetermined parameter selection. Finally, the conventional secondary control and LQR methods are demonstrated and compared with simulation.
