Congratulations Dr. Hamed Valipour! 🎉

With great contributions to the #PowerElectronics and #rectifiers body of knowledge, Hamed Valipour has recently received his PhD degree! 👏

A month ago, Hamed defended his thesis on "High Efficiency Single-Phase Power Factor Correctors: Resonant Circuit and Flexible Topology" at The University of British Columbia, giving a grand finale to this key stage of his career.

Hamed’s Achievements Include:

• 3 peer-reviewed IEEE publications and 3 IEEE conference presentations
• Industrial collaborations with Alpha Technologies on #PFC, #ResonantConverters, and #BatteryChargers
• Vice-Chair of the IEEE Power Electronics Society Chapter in Vancouver IEEE Power Electronics Society

Awards and Fellowships

• Four Year Fellowship Award (2016 - 2020), G+PS, UBC
• Graduate Student Initiative Award, 2018 & 2019, UBC

We are grateful to have had Hamed contributing to the success of #martinordonezlab all of these years and wish him the best with his new position at @SMPCT.

We would also like to thank Chair Gary Schajer; Supervisor Committee members Martin Ordonez, Bill Dunford, Navid Shafiei; Examiner Committee: Shahriar Mirabbasi and Mauricio Ponga; and External Examiner Akshay Rathore for their participation. Special thanks as well to Mohammad Mahdavi for his constant contributions to Hamed’s work.

Abstract for Hamed Valipour’s PhD Thesis

Title:
“High Efficiency Single-Phase Power Factor Correctors: Resonant Circuit and Flexible Topology”

Abstract:

Rectifiers with Alternating Current (AC) input and Direct Current (DC) output are required in many applications to regulate the output and provide a Power Factor Correction (PFC) capability. There are different applications for PFC rectifiers: wide-range and narrow-range.

The purpose of this work is to propose two approaches to improve efficiency while keeping the performance high in both wide and narrow-range rectifiers.

Wide-range applications require PFC converters to support extended variations in input voltage. A PFC converter capable of coping with a wide input voltage range (90VRMS – 530VRMS) would significantly decrease costs and streamline development. In this work, a reconfigurable PFC converter is proposed which provides a high and flat efficiency curve throughout the entire operating voltage range. This converter has:

• Flexible bridgeless structure with simple control
• Low current ripples and low common-mode noise
• Startup inrush current handling capabilities

Narrow-range applications are also studied, where variations in input voltage are minimal. An advanced LLCC resonant structure is proposed, improving efficiency in these cases.

The proposed design:

• Operates first in a DC/DC environment and later modified for AC input with a bridgeless configuration
• Enables soft switching for semiconductors without adding extra elements, using passive components in the design as a resonant tank
• Provides continuous input current with small inductances, ensuring an inherent PFC capability with single-loop control

These converters offer simple, symmetrical structure and easy control. The proposed solutions are analyzed both theoretically and experimentally, and their performance is compared to conventional structures, showing efficiency improvements and better performance.

Learn more about Hamed and his work by visiting our Website