Date of Graduation
8-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Engineering (PhD)
Degree Level
Graduate
Department
Electrical Engineering
Advisor/Mentor
Mantooth, H. Alan
Committee Member
Zhao, Yue
Second Committee Member
Chen, Zhong
Third Committee Member
Huitink, David
Keywords
Magnetic current sensor; Power electronics; Rogowski coil current sensor; Switching current measurement; Wide bandgap devices
Abstract
Accurate switching current measurement plays a pivotal role in characterization of power devices, overcurrent protection, and real-time control of system-level operations in power electronics applications. However, the ongoing revolution in power electronics, driven by the emergence of wide bandgap power devices operating at megahertz (MHz) switching frequencies, introduces challenges for current sensor design. The urgent issue now is the need to increase current sensor bandwidth significantly to adeptly capture the rapid switching speed current. Additionally, the trend towards high power density and compact power converters in various applications demands current sensors that are not only compact and nonintrusive but can also be seamlessly integrated into existing power systems. Currently, all the commercial current sensors fall short of incorporating all these essential features. This dissertation presents a high-bandwidth Ω-shaped current sensor, consisting of an Ω-shaped copper tube, Rogowski coil and an external integrator, to achieve precise switching current measurement. The designed structure allows easy integration into various current paths. And a multi-objective optimization based on a genetic algorithm and a finite element method is developed for the comprehensive design of the Rogowski coil. Subsequently, three optimized solutions of coil geometry with bandwidth and sensitivity as optimization objectives are selected for comparison. Moreover, an external differential integrator and its associated design guide are introduced. Finally, comprehensive double pulse tests (DPT) and multi-pulse test are performed under 800 V/70 A, 400V/170A conditions. The test results of the three distinct coils validate the effectiveness of the proposed automated optimization methodology and external integrator design. The Ω-shaped current sensor consistently exhibits a faster response and maintains over 10 mV/A sensitivity compared with a 30 MHz commercial Rogowski coil.
Citation
Du, X. (2024). Ω-shaped Rogowski Coil Current Sensor Optimization Design in Power Electronics Applications. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/5517