NC State University & FREEDM Represent at ITEC 2021

Several Ph.D. level students from the College of Engineering at NC State University participated in the IEEE ITEC 2021 conference in June. Tomas Sadilek, NC State University and FREEDM Ph.D. candidate, was recently recognized by the organization for his paper titled Design and Evaluation of SiC Active Soft-Switching Cell for 1-ph/3-ph Universal Voltage Input PFC for On-Board Charger Applications. Tomas works under FREEDM Director Iqbal Husain, ABB Distinguished Professor of Electrical Engineering.

What problem does this research help solve and who will benefit? 

This research work will benefit on-board chargers for electric vehicles, which need to operate with high efficiency for both single phase and three phase grid connections. Currently, the active front end of these chargers is hard switched, which limits the practical switching frequency to about 40 kHz. This research proposes an active soft-switching cell concept, which enables the active front end to operate at 100 kHz without efficiency loss for both single phase grid connections found at residential locations and three phase grid connections found at industrial locations. As a result, the input boost inductor and filter size can be reduced, which in turn increases the charger power density. Making the on-board charger smaller will free up volume in electric vehicles, a highly desirable feature.

ITEC 2021, held June 21-25, 2021, is a conference aimed at helping industry in the transition from conventional vehicles to advanced electrified vehicles.  NC State Professor Srdjan Lukic, FREEDM Deputy Director, was this year’s General Chair, and FREEDM alum Rishabh Jain was a Publication Track Chair. The conference is focused on components, systems, standards, and grid interface technologies related to efficient power conversion for all types of electrified transportation, including electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles (EVs, HEVs, and PHEVs) as well as heavy-duty, rail, and off-road vehicles, airplanes and ships.

Abstract: Design and Evaluation of SiC Active Soft-Switching Cell for 1-ph/3-ph Universal Voltage Input PFC for On-Board Charger Applications

Authors:  Tomas Sadilek, Yungtaek Jang, Peter Barbosa, and Iqbal Husain

A detailed analysis and experimental evaluation of a continuous-conduction-mode (CCM), pulse-width-modulated (PWM), boost-type active soft-switching cell suitable for 1-ph/3-ph universal-voltage-input PFC for on-board charging (OBC) applications is introduced. The soft-switching cell features zero-voltage switching (ZVS) of all switches, reduced reverse-recovery loss at any operating point, and simple control. The cell achieves high efficiency for converting low line voltage to the high dc-link voltage required for the OBC dc-dc converter. The evaluation of the concept was performed on a single-phase leg 3.4 kW prototype designed to operate at 220 VRMS line input and deliver 650 V output. The prototype achieves 97.8% efficiency at full load and 100 kHz switching frequency. The soft-switching PFC rectifier concept naturally morphs between an interleaved totem-pole converter for 1-ph ac line voltage and a 3-ph converter for 3-ph ac line voltage.

For more information contact Tomas Sadilek.


Additional Papers and Technical Sessions presented during the ITEC 2021 conference include:

A Methodology to Select the Number of Cascaded Cells for a Medium Voltage Multilevel AC-DC Solid State Transformer

Vishnu Mahadeva Iyer, Shrivatsal Sharma, Subhashish Bhattacharya – NC State University, FREEDM Systems Center

Optimized Highly Efficient SSCB Using Organic Substrate Packaging for Electric Vehicle Applications

Utkarsh Mehrotra, Bahji Ballard, Tzu-Hsuan Cheng, Jayant Baliga, Subhashish Bhattacharya, Douglas C Hopkins – North Carolina State University

Analysis of Different Operating Modes of PMSM During Regeneration with Uncontrolled Rectifier

Nithin Kolli (1), Prerit Pramod (2), Subhashish Bhattacharya1 – (1) North Carolina State University, (2) Norwegian University of Science and Technology

Torque Ripple Reduction of Interior Permanent Magnet Machine Using Asymmetric Q-Axis Rotor

Md Sariful Islam, Iqbal Husain, Adeeb Ahmed – North Carolina State University

A Design Optimization Approach for Dual Active Bridge Converter for Multiple Vehicle Classes with Disparate Input DC Voltages

Suyash Sushilkumar Shah, Subhashish Bhattacharya – North Carolina State University

Constant Power Load Analysis in Droop Controlled Microgrid for More Electric Aircraft

Niloofar Ghanbari, Subhashish Bhattacharya – North Carolina State University

Suppressing Circulating Currents in Battery Management of Droop-Based DC Microgrids

Niloofar Ghanbari, Subhashish Bhattacharya – North Carolina State University



SiC enabled MV Power Conversion System and Power Dense High Efficiency Engine Coolant Capable 200 kW SiC Inverter for Heavy Duty Vehicles

Dr. Subhashish Bhattacharya, Duke Energy Distinguished Professor, Electrical and Computer Engineering, North Carolina State University

For additional information about any of the topics above, please contact the author by locating them on our People Page on this website.