Congratulations Dr. Jun (Jeremy) Min!

A successful PhD graduation is the result of dedication, determination, and a relentless pursuit of knowledge. Congratulations Dr. Jun (Jeremy) Min!

Jeremy defended his PhD thesis titled “Bidirectional Resonant Chargers for E-Mobility” at the University of British Columbia.

Jeremy’s Achievements

• 3 journal papers published in IEEE Transactions on Power Electronics

• 3 conference papers published in IEEE Energy Conversion Congress and Exposition (ECCE)

• 1 conference paper published in IEEE Applied Power Electronics Conference and Exposition (APEC)

• 3 years of industrial collaborations with Delta-Q Technologies and Enersys as a research scholar, researching and developing new technologies.

• 2 years leading lab recruitment efforts as a member of the HR team.

• Contributions to the IEEE community as the Vice Chair of Power Electronics Society (PELS) of the Vancouver Section.

Awards and Fellowships

• Four-Year Doctoral Fellowship (awarded for UBC’s best PhD students)
• Graduate Student Initiative Award (awarded to graduate and postdoctoral students of UBC)

We are grateful to have had Jeremy contributing to the success of #martinordonezlab all of these years and wish him the best of luck in his future endeavors.

Acknowledgments

We would like to express our gratitude to:

• PhD Examination Chair: Steve Cockcroft
• Supervisory Committee: Martin Ordonez, Juri Jatskevich, and Navid Shafiei
• Examiner Committee: Shahriar Mirabbasi and Curtis Berlinguette
• External Examiner: Mehrdad Kazerani

Abstract for Jun (Jeremy) Min’s PhD Thesis

Title: “Bidirectional Resonant Chargers for E-Mobility”

Abstract:
This thesis investigates the development of efficient bidirectional chargers, an integral component for advancing e-mobility. Electric vehicles (EVs), energized by renewable sources, could mitigate power grid instability by returning stored energy when renewables are less available. However, the battery voltage in EVs can vary widely based on the EV’s application and the battery’s State of Charge (SoC). This necessitates employing various bidirectional charger techniques to handle a broad range of battery voltages when connected to the renewable energy grid.

Three innovative techniques are proposed:

1. Asymmetric Parameters Methodology (APM):
   This technique enables the design of asymmetric resonant tanks in bidirectional resonant CLLC DC/DC stages. APM, optimized through a statistical Design of Experiments (DoE) approach, narrows the bidirectional switching frequency range, reduces component stress, and allows for a smaller transformer size.

2. Unified Bidirectional Resonant Frequency Tracking Method:
   This method reduces resonance tracking costs and complexity for CLLC DC/DC stages while improving efficiency under parameter deviations. It is based on two key findings:

   • Maximum efficiency for charging and discharging occurs at a variable, but identical, resonant frequency.
   • The voltages at both ends of the resonant tank remain in phase at this frequency during bidirectional operations.

3. Cascaded Half-Bridge-Based Multi-Level Multi-Port Bridgeless PFC Rectifier:
   This technique, used in the AC/DC stage of chargers, divides high-voltage DC bus voltage into multiple low-voltage ports for the following CLLC DC/DC converter stage. This design allows the transformer ratio to be close to 1. Compared to a cascaded full-bridge PFC, this approach cuts the number of switches per cell by half while maintaining the same output ports. It also reduces input current ripple by minimizing volt-seconds on the boost inductor.