Alumnus Profile: Prof. John G. Hayes of University College Cork

Alumnus John G. Hayes, associate professor at University College Cork, Ireland, is the lead author of the best-selling textbook on electric vehicles, Electric Powertrain: Energy Systems, Power Electronics and Drives for Hybrid, Electric and Fuel Cell Vehicles, published in 2018 by John Wiley & Sons. John earned his master’s degree in electrical engineering from the University of Minnesota Twin Cities in 1988, under the guidance of Regents Professor Ned Mohan. 

Here, in his own words, John shares his thoughts on his recent book and his professional life, as shaped by his journey from Cork, Ireland, to the University of Minnesota, and back to Cork, with all the stops in between.


Electric Powertrain is the result of my experience in the power electronics industry, and my work as an academic in the field. Several years ago, I could see that with battery technology having greatly advanced since the General Motors EV1, electric vehicles (EVs) had reached a tipping point. Looking at a distance from Cork, I decided that the best contribution that I could make was as a teaching academic. So I spent three years writing the book, setting it up to be used as a university-level teaching textbook or industry reference, complete with the relevant theory, applications, examples, and problems.

Electric Powertrain  is set up to be used as a university-level teaching textbook or industry reference, complete with the relevant theory, applications, examples, and problems.

I was very familiar with my graduate advisor Regents Professor Ned Mohan’s many textbooks in the power field and I appreciate that he is always focused on student learning and support. Following his example, I designed the book to be student and instructor friendly. The textbook has been a success, adopted by dozens of universities across the United States, Latin America, Europe and Asia. It is also Wiley & Sons’ highest selling university textbook on electric vehicles.

I really enjoyed developing the book as it allowed me to write about what I knew from my previous professional experience, but more importantly, to study, to understand, and to document the many other areas which I knew to be important. While I relished the process of writing the book, and watching its successful adoption by institutions, I am also equally driven by the opportunity it has afforded me to mentor and advise colleagues worldwide on the devising and adopting of electric vehicle curricula. I have also found the public engagement aspect of the effort energizing, exciting, and challenging. It gives me the opportunity to engage with and educate the public on electric vehicles across TV, radio, print, and the web, a fun and new world for me.


I had been working in the power electronics industry in Los Angeles (having moved there in 1988 after graduating with my master’s degree) when I saw a job advertisement for a power electronics engineer to work on the new electric vehicle program of General Motors. Hughes Aircraft, a leader in aerospace at the time, had been purchased by General Motors in 1985. The electric vehicle work was carried out by a subsidiary of Hughes Aircraft in Culver City, close to the airport in Los Angeles. I joined General Motors Hughes Aircraft in 1990. The Culver City facility where we worked was historic as it was the facility where the legendary Spruce Goose had been built during World War II. General Motors went on to introduce the first modern production electric vehicle, the GM EV1, in 1996. Thus, the new world of electric vehicles, with which we are all familiar today, originated in Los Angeles around 1990. You can also trace the technical ancestry of Tesla Inc. back to this time. It is amazing to see how this green energy movement has exploded over the past 30 years.

Image of Mars rover Opportunity

The Li-ion battery, (for which Goodenough, Whittingham, and Yoshino won the Nobel prize in 2019), has been revolutionary in transforming our world, enabling cell phones, laptops and electric vehicles. Electric vehicles can play a significant role in reducing carbon emissions, and eliminating toxic transportation emissions in our cities, both of which could mitigate climate change. We will see greater penetration of electric vehicles across society in the next decade. One of my favorite memories from my book writing endeavor was tracking the Mars rover Opportunity as it travelled across Mars for 14 years, completing a marathon in 2015. If EVs can make it on Mars, they can make it here on Earth!


I earned my BE degree in 1986 from University College Cork (UCC), on the south coast of Ireland. I had a great interest in power electronics and electrical machines. When I was finishing college I consulted with my academic advisor who suggested that I contact Prof. Ned Mohan at the University of Minnesota and inquire about pursuing a graduate degree in the Twin Cities. I applied, and was thrilled to be admitted to the University with a scholarship from the Schott Foundation. I spent two great years in the Twin Cities, earning my master’s degree in 1988, after which I moved to Los Angeles for employment in the power electronics industry.


Academically, the experience was challenging, but so educational. I fondly remember the classes taught by Professors Albertson, Mohan, Ogata, Plice, Riaz, Robbins, Kinney, and others. Socially, I loved my two years at the University. I smile when I think back to those days. It was a different world for a young Irish lad. I had a thick Irish accent which I had to adapt as I realized that people could not understand me. I even attended my first ever St. Patrick’s Day parade in St. Paul in 1987! 

I loved playing soccer in the fall with the KHK fraternity engineering team on the University fields in St. Paul, and during the summer with the Minneapolis Kickers on fields all around the Twin Cities. My friends and I enjoyed the hostelries around the campus in Dinkytown, by Seven Corners across the bridge, and the fun visits to Norma Jean’s night club. We swam in the lakes and enjoyed visiting Uptown and downtown Minneapolis, and attended some great concerts at First Avenue. Watching the Gophers play college football, and the Twins at the Hubert H. Humphrey Metrodome were all truly memorable. And who can forget the great Kirby Puckett, the Twins Hall of Famer!

Outside of engineering I developed some great friends, in the English department, and through soccer. A special mention to all my friends in Minnesota who made life so memorable and with whom I am in contact today: Tony, Charlie, Conor, Jin, MaryBeth, Chris, Sofia, Malcolm, Leigh, Richard, Carol, Jurgen, Alvaro, Sabine, Dean, Mark, and Fernando.


The University of Minnesota is in the wonderful position of having Prof. Mohan as a Regents Professor. He is a world-renowned academic in power electronics and electrical machines. These technical areas are the pillars of the green energy movement from solar to wind to electric vehicles. I can happily say that I was truly privileged in my early 20s to have been a student of Prof. Mohan. Over thirty years later, he is still heavily influencing my work. One of my great part-time colleagues on the GM EV1 program was my old mentor Dr. Chris Henze. Chris (previously a doctoral advisee of Prof. Mohan, co-supervised my master’s thesis) consulted with us for several years in California on the GM EV1 development. Chris was a calm, sage, and experienced expert in power electronics, whose talents were called on again and again as we developed the new electric vehicle technologies. Dr. Tony O’Gorman, a fellow Cork student at the University, has also worked for many years on electric vehicles across the US.


For family reasons, in the mid 90s, I pursued a part-time thesis-only PhD back in Ireland at Cork.  I wintered by the beach in Los Angeles while working at GM and summered in Cork researching electric vehicle technologies. After a decade at GM, I left in 2000 and my Michigan-born wife, Mary (I had met Mary working at GM), and I moved to Cork for me to work as an academic. 

It seemed like a fun move at the time, to try something different besides living by the beach. All these years later, we are still in Cork, but  we visit Michigan and Los Angeles on a regular basis. Mary has since left her mechanical engineering career behind her and works as a yoga teacher to balance our life challenges and the parenting of our three teenage daughters, Madi, Tasha and Saoirse.

In my teaching and research, I am very active across electric vehicles, power electronics, electrical machines, and applied electromagnetism. I particularly enjoy working on collaborative problem-solving projects with world-leading US companies such as United Technologies (now Raytheon), General Motors, Analog Devices, Advanced Energy, Bourns, Moog, and more. I have a strong relationship with Germany-based SMA Solar Technology AG, who are world leaders in photovoltaic solar electric and renewables. My newest project is a research program on electric aircraft which will bring a whole new set of challenges. My  students gain greatly from the industry collaborations with opportunities for mentoring, technical expertise, laboratory facilities, internships, and careers. For me, it’s fun, energizing and productive to tackle new problems with young minds and industry experts.


Take a power electronics class. It opens up fascinating areas that are changing the world, from EVs to renewables to data centers to medical devices, while integrating diverse technologies such as semiconductors, magnetics, control, mechatronics, machines, and energy storage. There are a number of technologies currently being adopted and making the power electronics field even more interesting and impactful: batteries and field cells for electromobility; wide-band-gap semiconductors improving efficiency and reducing converter size; increased digitization, as control moves from the analog to the digital world. But remember that while it’s fun to spin a motor and power a vehicle, it can also be dangerous: explosions and fires come with the territory! One of our big challenges is making our technologies safe.


First, I am really looking forward to the new book on electric drives by the University’s own Prof. Mohan and Dr. Siddharth Raju in the fall. Second, I wish well to all my friends and acquaintances at the University of Minnesota. It is a wonderful world-class institution. I was hoping to visit this year but I look forward to the visit when travel opens up again. 

In the meantime, wishing you all “Sláinte” from my hometown of Kinsale, County Cork!

Learn more about Prof. Hayes’ research interests and publications

A Chinese language edition of John’s textbook Electric Powertrain: Energy Systems, Power Electronics and Drives for Hybrid, Electric and Fuel Cell Vehicles is expected in 2021.