Replacing the conventional ICE (Internal Combustion Engine) in an Automobile with an Electric Motor poses several challenges related to Energy Density, Driving Range and Power Delivery.
Ajay Poonjal Pai (PhD), our next pathbreaker, Application Engineer at a leading power semiconductor company, builds semiconductors for e-mobility, with the aim to make electric cars practically feasible at scale and more efficient.
Ajay talks to Shyam Krishnamurthy from The Interview Portal about his childhood fascination for electrical engineering that led him to work in the domain of electric vehicles as a technological alternative to conventional vehicles.
For students, its a given that you are going to spent atleast 30 years of your life pursuing your career. So, choose your career wisely, based on what drives you !
Ajay, can you tell us about your background?
My name is Ajay. I hail from Mangalore, a city on the west coast of India, where I did my schooling and college. My father worked as a senior manager in Electrical Maintenance at an Iron and Steel company, and my mother is a housewife. I have a younger brother who is working in data analytics. My wife is a software engineering professional.
I am very passionate about sports like Badminton, Cricket and Tennis. I also enjoy long cycling trips, travelling and trekking. I have had the opportunity to volunteer for different organizations in various capacities. I like to try new things and constantly challenge myself by going out of my comfort zone.
What did you do for graduation/post graduation?
I pursued my B.Tech in Electrical and Electronics Engineering from the National Institute of Technology Karnataka (NITK), Surathkal. After that, I worked for 2 years at NTPC Ltd., in the field of operation and maintenance, following which I came to Germany to pursue my masters in Electrical Engineering., from RWTH Aachen University. This gradually led me to pursue a PhD specializing in Power Semiconductors for Electric Cars, from the University of Erlangen-Nuremberg, Germany.
For my Masters in Electrical Engineering, I was fortunate to receive the Prestigious Bildungsfonds “German National Scholarship” for my academic and co-curricular contributions.
What made you choose such an offbeat, unconventional and uncommon career?
Electrical Engineering has fascinated me ever since high school. I remember getting my hands dirty with old electrical motors, mini transformers and other components from old electrical equipment, thanks to the kindness of a friend at a local scrap shop. I was lucky to have a practice oriented electronic course offered at school, where we learnt basic concepts of electronics and built simple circuits. The key motivator for me, however, was my father who is in the electrical engineering profession. I grew up watching him work with Electrical Systems, and gradually realized that this is the field that always amazed me, leading me eventually to a career in Electrical Engineering.
I was also fortunate to have had several amazing teachers over the course of my education, who motivated me to eventually choose the career that I am in. I remain highly indebted to them for positively shaping not only my education, but also my attitude, thinking and personality.
How did you plan the steps to get into the career you wanted?
Honestly, I hardly plan too far ahead. My philosophy is to really treat life as it comes, and take one step at a time. It is important to “like the journey”, as they say. I believe that there is a certain guiding force which leads one to his/her goal, and trust my intuition more than anything else. A plant grows in search of sunlight. Likewise, I did the same by going in search of what interests me the most, which has led to where I am right now.
After my undergraduate studies, I was keen on gaining some practical experience and therefore took up a job at NTPC Ltd., India’s largest power utility. This job gave me a good overall understanding of electrical power generation as well as people management. Two years into the job, I realized that my passion was to specialize in power electronics. As I was also passionate about cars, e-mobility was a very attractive domain for me, and this led me to Germany, the hub of automotive Innovation. Germany used to offer (and still does) a multitude of public funded courses with only nominal fees, topped with scholarships, which was (is) very attractive for students.
I did my masters thesis at the EON Energy Research Centre in Aachen. Renewables such as Wind and solar energy have reached quite a high level of penetration in the electrical grid. However, they are intermittent in nature, often resulting in the energy supply being unmatched to the demand. Therefore, it would be a good idea to store the excess solar energy generated during a hot sunny day or the excess wind energy during a windy spell, in a large battery to use them later during high demand. This makes the electrical grid more stable. My research was focused on the power converter for such an application.
By the end of my masters, I had realised that I wanted to further specialise in e-mobility, and this is when I came across an opportunity to pursue a PhD in the semiconductor industry, specialising in Silicon Carbide technology for semiconductors. I had also focused on this technology for my master thesis, and I was convinced that it is a promising technology.
My PhD thesis was focused on investigating and quantifying the benefits of Silicon Carbide (SiC) based transistor technology on the efficiency and driving range of electric vehicles, and also the challenges faced in adopting them.
Electric Vehicles (EV) are getting popular all over the world. Governments have realised that EVs are the way to go for emission-free mobility, and hence promoting them. Compared to a conventional car, where a petroleum-based fuel supplies energy to an Internal Combustion Engine (ICE), EVs have a large battery to supply electrical energy to an electrical motor. The energy density (energy per unit volume or mass of the fuel/battery) of electrical batteries are significantly lower compared to fuels like petrol. Also, the time taken to charge a battery is significantly longer compared to the time taken to fill a car with a full tank of petrol. As a result, the driving range (maximum distance the car can travel on a full charge of the battery) of an EV is still a key concern for mass adoption of EVs. Consequently, EV manufacturers try to make their systems as energy efficient as possible, to maximise the driving range. A key component of an EV is the so-called “traction inverter”. The traction inverter consists of power transistors that “invert” the direct current (DC) from the battery to an alternating current (AC) needed for the motor. In this process, energy losses occur in the transistors, thereby impacting the driving range. I investigated the benefits of Silicon Carbide (SiC) based transistor technology on the efficiency and driving range of electric vehicles, and also the challenges faced in adopting them.
Can you explain the concept of semiconductors in e-Mobility and how they are a gamechanger for EV operations?
As already mentioned, electrical motors need an AC whereas the batteries provide DC, making an intermediate conversion from DC to AC necessary. Moreover, to control the speed and torque of the electrical motor (based on the accelerator pedal), it is needed to precisely control the voltage, current, frequency etc. supplied to the motor. This can be done with the help of power semiconductor transistors. Power Transistors are electrically-controlled switches that handle high power (several tens to hundreds of kilowatts). By switching the transistors on and off several thousands of times per second, the battery voltage can be chopped to control the output voltage, current, frequency etc. The same task could theoretically be accomplished with mechanical switches/relays. In comparison, power semiconductors make it significantly more efficient, faster, reliable and compact. A semiconductor chip with an area of a rupee coin, and roughly as thin as a strand of human hair, can handle several tens of kilowatts. This enables power electronic systems that can handle over hundred kilowatts in a volume of just 4-5 liters. To give a loose analogy only to create a feeling for the scale, a small water geyser in a typical Indian home consumes only a couple of kilowatts. So an automotive system handles roughly the same power as 50 such water geysers in a volume equivalent to about 5 tetra packs (assuming 1 tetrapack =1L)) placed next to each other.
How did you get your first break?
When I came across an opportunity to pursue a PhD in the semiconductor industry related to e-mobility, i decided to take it up because the PhD thesis would give me the chance to research and apply this promising technology for EV applications which made this offer very attractive to me.
What were some of the challenges you faced? How did you address them?
The first challenge to pursue higher studies was “myself”. I had to convince myself to quit a secure, well paying job in order to pursue my dream. This was a huge gamble, with severe financial risks. Fortunately, my parents were very supportive and stood solidly behind me which made my decision easier. It is largely their inspiration that continues to drive me.
Studying in a foreign country is a great experience, but it comes with a set of challenges. From learning a foreign language (in this case, German), to getting adjusted to a new culture of life and work, to making new friends, initial hurdles are plenty. But like everyone else, I managed to overcome them.
Where do you work now? Can you tell us about your research on Electric Vehicles?
I am presently working at a leading power semiconductor company, as an Application Engineer for Power Semiconductors, with a focus on E-Mobility. E-mobility is currently growing out of its nascent cocoon, which presents several challenges as well as opportunities. As power electronics experts, it gives us a great opportunity to contribute positively to society by changing the way the world “moves” for the greater good. The widely-talked-about greenhouse emissions are an imminent threat to nature, and to human existence. E-Mobility might be the answer to many of these problems. We work on building semiconductors for e-mobility, which make electric cars possible in large volumes. Moreover, we focus on making them “efficient”, which means you can either drive more kilometers with your electric cars, or drive with less emissions for ICE-based cars.
What do you love about your job?
The thing I love the most about this job is that it puts me in direct contact with the threats that the world faces as far as greenhouse emissions are concerned, and provides me the chance to come up with solutions to enhance the living conditions of the society.
How does your work benefit society?
Today, public health is threatened by the pollutants emitted by conventional Internal Combustion Engine (ICE) Cars, and many nations around the globe are acknowledging this threat. There are several technological alternatives that have been presented. One promising alternative is the electric vehicle (EV), which runs on electrical energy stored in a battery. The advantage of the EV is that it is pollutant free (at least locally). There are emissions still at the power plant where the energy used to charge the battery is generated, but this can be overcome by switching to renewables like wind and solar. This has the potential to improve the air quality drastically, particularly in large cities with a high density of ICE cars. This way, working in the e-mobility domain presents vast opportunities to “refine” the way societies commute, and offer enhanced living conditions for people.
Tell us an example of a specific memorable work you did that is very close to you!
While working at NTPC Ltd, I was posted at a town in Uttar Pradesh. Together with some colleagues we took up the task of teaching and training some economically not-so-well-off school students of the adjacent locality in the evenings and weekends. This was a highly satisfying and memorable experience for all of us.
Your advice to students based on your experience?
One usually spends ~30 years in a professional career, which is not a short time to compromise doing something that does not interest them. This is why I would advise students, if I may, to spend the early part of their education trying various things, and eventually figure out what it is that really fascinates them. The rest of the education/training should be spent on actually chasing their passion, trying to gather the knowledge and skills that would make them an expert in their respective field. One student might be fascinated by engineering, whereas another might have a passion for Music, and yet another one for sports. Yet, they could all be successful in their respective fields if only they chase their dreams.
Another advice would be to never stop learning. What we know is only a drop in the ocean, and so long as there is the urge to know more, one can be sure that they will not be left behind by the latest advancements in their field.
Some great aids to decision making are “data” and “reasoning”. My tip would be to be open-minded and always challenge one’s own decisions with questions like” why”, “how” and “what”, and to also back them with solid data. This way, one can be sure not to make decisions purely based on emotional factors.
One last tip would be “networking” and “collaboration”. It is said, “If you want to walk fast, walk alone. If you want to walk far, walk together”. Everyone brings a new set of skills and a new piece of information to the table. Thus, networking and teaming up with like-minded people can help to go farther.