He is also Grainger Endowed Chair Emeritus in Electric Machinery and Electromechanics in Electrical and Computer Engineering and an alumnus of the department, having earned his master’s degree and PhD in electrical engineering at Illinois in 1980 and 1982, respectively. Professor Krein joined the ECE ILLINOIS faculty in 1982, departed to work three years in industry, and re-joined in 1987. He has helped establish the department as a leader in power electronics, a field that involves the study of semiconductors and electronic circuits for the conversion and control of energy. This energy processing is critical in the development of personal computers, industrial automation, high-performance communication networks, home appliances, alternative energy systems, and most energy-intensive applications. He retired in 2015 and is still working at ECE ILLINOIS as a research professor, involved in the NSF-funded Center for Power Optimization of Electro-Thermal Systems (POETS).
Professor Krein made significant strides in developing alternative energy sources, particularly the optimizing the use of solar power as a feasible energy resource. In addition to his research, he is the author of Elements of Power Electronics, the first undergraduate text to provide an engineering science framework for power electronics. He has been honored with a Fulbright Senior Scholarship, named an IEEE Fellow, and was elected to the U.S. National Academy of Engineering. He has been awarded thirty-nine U.S. and four European patents.