Chapter Events


The SFBAC (combined Santa Clara Valley, San Francisco, & Oakland/East Bay) IEEE Power Electronics Society (PELS) and the Santa Clara Valley Magnetics Society are very pleased to invite you to our September chapter meeting. We are excited and honored to have Utah State University’s Bryce Hesterman to speak on the topic of “Modeling Transformer Winding Behavior of Multi Output Power Supplies using Mutual Impedance Effects.” Additional event details can be found below. 

Talk Title: Modeling Transformer Winding Behavior of Multi-Output Power Supplies using Mutual Impedance Effects.

Date: Thursday, 16 September, 2021
Time: 11 am – 12 pm PST
Location: Virtual Meeting (logistics TBD)
Cost: FREE to all!!!

Abstract: Transformer equivalent circuits based on modeling magnetic coupling or mutual inductance describe important aspects of transformer behavior such as leakage inductance and cross regulation. Transformer equivalent circuits based on adding L-R networks typically focus on winding losses predicted by Dowell’s method, but they often don’t model coupling effects, and they typically don’t work well at predicting winding losses for transformers that supply independent loads or for transformers that have windings connected in parallel unless very complicated models are used. This presentation describes an equivalent circuit for transformers that models both magnetic coupling effects and winding losses while using a surprisingly simple structure. The key to this approach is that it is based on mutual impedances that have both inductive and resistive components. This equivalent circuit models the well-known magnetic coupling coefficients, but also models the lesser-known resistance coupling coefficients. This allows the model to accurately model frequency-dependent losses as well as frequency-dependent leakage inductances. The performance of a simulated phase-shifted bridge converter with two independent loads is compared to hardware results. Various effects of mutual impedance are illustrated including cross regulation, how an external ZVS inductor affects the winding losses, and how the frequency dependence of leakage inductances affects diode reverse recovery and the energy that needs to be snubbed.

Speaker Information: Bryce Hesterman is the Principal Research Engineer at the Utah State University Power Electronics Laboratory, which is the headquarters for the NSF Engineering Research Center for Advancing Sustainability through Powered Infrastructure for Roadway Electrification (ASPIRE). He provides advanced engineering support, oversight, and leadership on major research and development projects related to electric transportation. At Aerojet Rocketdyne he designed power electronics for in-space electric propulsion applications such as arc jets, ion engines, and Hall effect thrusters, and was the designated magnetics subject matter expert. At Advanced Energy Industries he designed power converters for applications in the plasma thin film industry such as wafer and CD/DVD metallization, and magnetic coatings on hard drives. He invented or co-invented several soft-switching and resonant power converter topologies used in energy-efficient products, and has been awarded 24 patents. He has authored or co-authored ten technical publications. He enjoys deriving new modeling and simulation techniques, and is now serving as a scientific advisor to, an online magnetics design platform. He also enjoys technical writing, hiking and photography. Bryce received BSEE and MSEE degrees from Brigham Young University. He is an active member of IEEE, and formerly served as chair of the Seattle Chapter of the IEEE Power Electronics Society.


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: Event virtual meeting info sent 24-48 hrs prior to event time only to those pre-registered.