Boundary Condition Independent Thermal Network Modeling of High-Frequency Power Transformers

Abstract

With increasing global power demands and the trend of miniaturization of power converters, electronic components are being pushed toward their thermal limits. This has accentuated the need for accurate and low-cost thermal models of electronic components. Lumped Parameter Thermal Network Modeling (LPTNM) is commonly used to evaluate the thermal performance of electronic components, but unlike semiconductors, transformer LPTNM is not standardized in the academic community. Due to this lack of standardization, most proposed transformer thermal models have not been evaluated for Boundary Condition Independence (BCI). This study presents a BCI thermal modeling approach for power transformers based on LPTNM. A thermal network model is developed by discretizing the transformer geometry into smaller volumes and evaluating the thermal resistances by approximating the three-dimensional heat transfer problem as a piecewise one-dimensional model. The network model/geometry discretization is iteratively improved for a set of different boundary conditions, resulting in a BCI model. The modeling approach is experimentally and numerically validated on a PQ40/30 transformer operating in a 3.3 kW switch mode power supply. The BCI transformer thermal model closely matches both numerical and experimental results with a fraction of the computational cost of the numerical model. The proposed BCI modeling approach provides a low-cost alternative to detailed thermal models and can predict transformer thermal performance for varied applications.

Acknowledgements

The authors would like to thank NSERC (CRDPJ505355-16) for providing the funding to make this project possible. The authors would also like to thank CMC microsystems for providing software access.

Disclosure statement

No potential conflict of interest reported by the authors.

Additional information

Notes on contributors

Anshuman Dey

Anshuman Dey received the B.E degree in mechanical engineering from Vishweshwaraiah Technological University, Bangalore, India in 2014. He is currently working toward a Ph.D. degree at The School of Engineering, University of British Columbia, Kelowna, BC, Canada. He is a research assistant at the Thermal Management and Multiphysics Flows Laboratory. His research interests include thermal management of electronic systems, multiphysics modeling, and numerical analysis.

Navid Shafiei

Navid Shafiei received the B.S. and M.S. degrees in electrical engineering from Kashan University and Islamic Azad University, Najafabad branch, Iran, respectively, and the Ph.D. degree in electrical engineering from The University of British Columbia, Vancouver campus, BC, Canada in 2005, 2011, and 2017, respectively. He currently works at Alpha Technologies, Ltd. (an EnerSys company), Burnaby, Canada as a power supply design engineer. His current research interests include advanced soft-switching methods in power converters, high frequency magnetics design and their application in high efficiency rectifiers for telecom applications.

Ri Li

Ri Li received four years training on fluid transmission and control technologies at Beijing Institute of Technology. He completed his M.A.Sc. and Ph.D. degrees in the MUSSL Lab at The University of Toronto. He is currently a tenured Associate Professor with the School of Engineering, University of British Columbia (UBC), where he is the founder of the Thermal Management and Multiphysics Flows Laboratory. Previous to his role at UBC, he was a research scientist at GE Global Research Center, NY, USA. His research interests centers on thermofluidics and inter-facial sciences in thermal management and cooling technologies.

Wilson Eberle

Wilson Eberle received the B.Sc., M.Sc., and Ph.D. degrees from the Department of Electrical and Computer Engineering, Queens University, Kingston, ON, Canada, in 2000, 2003, and 2008, respectively. He is currently a tenured Associate Professor with the School of Engineering, University of British Columbia, Kelowna, BC, Canada, where he is the Founder and Leader of the Energy Systems and Power Electronics Laboratory. His research interests include high-efficiency power conversion circuits and control techniques for a wide range of industrial and consumer applications. He is the author or coauthor of more than 70 technical papers published in various IEEE international conferences and IEEE journals

Rahul Khandekar

Rahul Khandekar received the B.E. degree in instrumentation engineering from Mumbai University, Mumbai, India, in 2001, and the M.S. and Ph.D. degrees in electrical engineering from the State University of New York at Binghamton, Binghamton, NY, USA, in 2004 and 2008, respectively. He is currently with Alpha Technologies, Ltd. (an EnerSys company), Burnaby, BC, Canada, where he is a manager of research and advanced development. In this role, he manages technology development in power electronics, embedded controls, and power systems as well as partners with universities to advance research for telecom, traffic, and datacenter applications. His research interests include applications of embedded controls in optics, robotics, and power electronics.