Lab Director: Hua (Kevin) Bai was born in Chifeng City, Inner-Mongolia, China in 1980. He received BS and PHD degree from Department of Electrical Engineering of Tsinghua University, Beijing, China in 2002 and 2007, respectively. Bai was a postdoctoral fellow and research scientist at the University of Michigan-Dearborn, USA, in 2007 and 2009, respectively. In July 2010 he joined the Department of Electrical and Computer Engineering, Kettering University, MI, USA as an assistant professor with tenure track, teaching Microelectronics (EE320), Power Electronics (EE424), and Battery Management System (EE591C). He is the director of Advanced Power Electronics Lab (APEL) and leads the power electronics group at Kettering,
devoting the effort to vehicle electrification.

His research interest is modeling, simulation and design of various power electronics systems, including variable speed motor drive system, high-efficiency and high-power battery chargers, photovoltaic inverter, electronics alternator in electric vehicles, and battery management system. From 2011, Bai, as PI, received ~$1.7 million research funds from OEMs (Chrysler LLC, Mahindra) and Automotive Suppliers (Magna, Tenneco, etc) in the Michigan area. He is the author of one book (Transients of Modern Power Electronics), 35 peer-reviewed IEEE journal papers and 25 conference papers. Meanwhile he holds five industrial patents and acts as the associate editor of SAE International Journal of Alternative Powertrains.


Solar based Bidirectional Battery Charging Station for Electric Vehicles sponsored by CZAR Power Ltd

Next-generation High-efficiency Battery Charger for Electric Vehicles sponsored by Hella Coporate Center USA Inc

Wide-bandgap Device Based 720V/380V 5kW DC/DC Converter sponsored by Bosch LLC and GaN Systems Inc

2.5kW 95%-efficiency Electric Alternator sponsored by Chrysler LLC

This project is to help Chrysler LLC design a 2.5kW 95%-efficiency isolated electric alternator for electric vehicles. This device is used to transfer power between 400V Li-Ion battery pack and 12V Lead-Acid battery. In addition to soft-switching control, a novel Maximum Efficiency Tracking Control is used to realize SRC for the secondary MOSFETs through software.

The whole project is a codevelopment between APEL and Chrysler Powertrain Group. The system is able to deliver 2.5kW when input varies from 450V to 200V and output varies from 14V to 6V. Simplorer is used to simulate the system performance.

PI: Kevin Bai
Research Team: Wei Guo, Allan Taylor, Chenguang Jiang and Chen Duan

12V/1kW Motor Drive System for an Exhaust Burner's Secondary Air sponsored by Tenneco 

In order to decrease the emission of diesel engine vehicles, APEL and Tenneco collaborated to develop a 12V/1kW motor drive system to drive an air pump for a burner, which will provide supplemental heat as needed to manage particulate filter soot loads and activate catalysts to further reduce emissions. Soft switching along with advanced system packaging technologies are adopted. Whole system efficiency is >90%.

PI: Kevin Bai
Research Team: Allan Taylor, Nelson Wang

Three-phase 11kW 97%-Efficiency PFC for Battery Chargers in PHEV sponsored by Magna Ecar

APEL worked with Magna Ecar to design a 97% efficiency front-end Power Factor Correction Controller. System efficiency is 97% at 10kW and 98% at 6kW.

PI: Kevin Bai
Research Team: Allan Taylor and Gyula Szatmari-Voicu

10kW 97%-Efficiency DC/DC Converter for A Battery Charger in PHEV sponsored by Magna Ecar

APEL worked with Magna Ecar to design a 97% efficiency DC/DC converter. System efficiency is 97% at 10kW when charging the battery from 250V to 400V, and 95.9% at 8kW when battery voltage >400V.

PI: Kevin Bai
Research Team: Allan Taylor and Gyula Szatmari-Voicu

2kW Wireless Charger For PHEV

APEL team designed a 2kW wireless charger. Overall system efficiency is >86% when charging the battery at 2kW. Distance between on-board and off-board parts >15cm. This project now is seeking the sponsors.

55kW Electric Powertrain for Electric Vehicles for China EV market

APEL designed a 55kW electric powertrain. The system includes one control board and one gate-drive board. The whole board dimension is 4.5 in * 7.5 in. IGBT Hybrid Pack 1 is used. The whole system design adopts all vehicle-level components. Field Oriented Control is used to drive a 55kW Permanent Magnet Synchronous Motor. Various system protections are included to enhance the reliability, which include but not limited
Over voltage/current;
Under voltage/current;
Phase open circuit;
Over temperature;
IGBT desaturation;
Humidity protection (coolant leaking);
Under voltage of 12V lead-acid battery…

APEL right now is collaborating tightly with China companies to design a 100kW battery exchange/charging stations, 100kW DC/AC inverter, etc. The next step is to 1) replace the present DSP with vehicle-level controllers (e.g., PowerPC) and 2) realize higher system integration.

PI: Kevin Bai
Research Team: Wei Guo, Allan Taylor, Gyula Szatmari-Voicu

Extended Kalman Filter Based Battery SOC Online Estimation for PDI Inc

APEL used Extended Kalman Filter to realize battery SOC estimation. Experimental results show that EKF method has higher accuracy than present Coulomb Counting method and is as accurate as OCV method. This control system was successfully used for PDI, a Michigan local battery company to estimate the impact of different charging algorithms on the battery lifetime.

PI: Kevin Bai
Research Team: Mori Yatsui, Nick Cramer and Xi Zheng

Electric Scooter for US College Students

APEL team right now is collaborating with Mahindra to design an E scooter for US college students.

PI: Kevin Bai
Team: APEL