Doctoral Defense

Study of Integrated TMR-based Current Sensing solution and Partial Discharge in Motor Windings fed with WBG Power Electronics

Sama Salehi Vala

May 10, 2024
1:00 PM
Light Engineering, Room 250
Advisor:  Fang Luo

Decreasing air quality has been a global concern for years, prompting exploration into various approaches to alleviate the issue. One proposed solution is the electrification of systems, a movement that initially targeted transportation, particularly through the introduction of electric vehicles, and has since expanded to encompass the aviation and naval sectors. Electric drives, pivotal in propelling electric motors, have emerged as a cornerstone in the transition from conventional fuel-based transportation to renewable energy-powered systems. While driving motors with motor drives offers improved efficiency, precise control, and enhanced functionality compared to traditional systems, it also presents challenges, particularly in terms of reliability.

In many applications such as aerospace, a critical requirement for motor drives is achieving high power density—meaning high power output in a compact, lightweight form. One solution to meet this demand involves increasing the switching frequency to reduce the size of passive elements and facilitate size and weight reduction. Furthermore, minimizing component spacing is essential for shrinking the size of motor drives, whether in power module-based or discrete-level power converters. This necessitates advancements in other converter elements such as controllers, sensors, and insulation systems. In power electronics systems, current measurement plays a crucial role in fault detection, diagnosis, protection, and control. Key features required for current measurement in high-density, high-efficiency converters include wide bandwidth, non-invasive integration, compact dimensions, high noise immunity, and wide temperature range stability. These features are essential for meeting the demands of modern power electronics. However, traditional current measurement solutions often fall short in covering all these aspects. In this study, a novel current measurement solution compatible with the diverse needs of modern power electronics systems, applicable for both power modules and system-level power converters, is proposed.

Furthermore, the advent of high-frequency switching motor drives brings about critical reliability considerations, particularly as the need for size and weight reduction leads to minimizing the use of insulation materials. Recent studies have highlighted the risk of insulation failure in motors fed by power electronics drives. Statistics indicate that a significant portion of failures in high and medium voltage equipment are attributed to Partial Discharge (PD). This study investigates the influence of various characteristics of the voltage generated by motor drives, such as rise time, duty cycle, and switching frequency, on PD patterns.