In today’s world, fossil fuels are still the main source of energy for transportation. Fossil fuels, which have been used for decades, bring with them many environmental problems. Fossil fuels, which increase carbon emissions and air pollution, are disadvantageous due to their high cost, as well as the damage they cause to the environment. Vehicles with electric motors are therefore also essential for our future. We met with Assoc. Prof. Dr. Derya Ahmet Kocabas from the ITU Electrical Engineering Department to discuss developments in this field.
Can you please introduce yourself?
I was born in 1972. After studying at Ankara Ataturk Anatolian High School and Ankara Science High School, I graduated from Istanbul Technical University Department of Electrical Engineering. I first completed my master’s degree at the same university in 1997, and my doctorate in 2005. I have been working as an academician at the same department in Istanbul Technical University since 1995. I received the titles of lecturer in 2005, assistant professor in 2009 and associate professor in 2021. I am also in charge of the Electrical Machinery Laboratory, academic advisor to the ITU Electric Vehicle Team, ITU Autonomous Boat Team and ITU Formula 1 Electric Vehicle Team.
It is a fact that electric vehicles have been in our lives for a long time. What are these electric vehicles actually?
As a result of the technological age, vehicles with electric motors that do not consume fossil fuels and operate cleanly, quietly and with high efficiency have been designed. Movement is achieved by converting the electrical energy from the battery into motion energy by means of an electric motor. Different types of electric motor structures (with internal and external rotors) and types (asynchronous motor, permanent magnet motors) can be used according to different mechanical connection types. Electric vehicles can be hybrid or fully electric. However, the main target is those of “fully electric” type. In order for it to do this independently of a source and to provide a good range, a battery as an energy store, a battery management system that can properly operate this battery, an electric motor to produce mechanical movement and a power electronic circuit to control this motor are needed. These are the main elements that differentiate an electric vehicle from other vehicles. All the remaining systems can be used exactly the same.
Can you tell us about the pros and cons of electric vehicles?
The first thing that comes to mind is the carbon emissions of internal combustion vehicles, atmospheric effects and leaving a cleaner world for future generations. We can suggest that there is no waste directly generated by electric vehicles, but production with clean sources is not always possible. The efficiency of combustion and gasoline engines is roughly 25%. In diesel engines, this rate is around 45% -50%. You will see an efficiency of 95% and above in powerful electric motors. You will use less energy to carry the load. It is prone to automatic control and works quietly. The disadvantage is that there is a range problem. You don’t ask yourself “Can I find a gas station if I go out on the road?”, but you may ask yourself "Can I charge my car?" Although the number of stations and charging capacity is gradually increasing, it is still within a certain limit. Depending on the region where you are in the country, the road itself and your driving techniques, your range may vary.
Can you draw a perspective on electric vehicles from the past to the present?
Due to battery technology limitations, the trend was towards hybrid driving systems. The boundaries of this are determined by battery technology and charging systems. With the developing battery technology, many commercialized fully electric vehicles have been launched in recent years. Charging time is also a criterion. The ability to charge for a long range is an obstacle to commercialization. This obstacle is also being overcome gradually. Of course, electric vehicles have started to be used more during this period. I believe that it will gradually become more widespread as the current needs are met, new cell materials and qualified batteries are discovered, their costs decrease and their performance increases.
Our electric vehicle TOGG will be launched to the market in the near future. What are your opinions on this? What would you like to say about this?
What will move the country forward in everything is “production”. Production in all sectors is a must in order to take a more effective role in the global arena. As for the electric cars segment, the electric vehicles in Türkiye are based on experience gained by transforming existing vehicles and researching them at universities for a long time. In fact, we can produce the electric motor, which is one of the main elements.
We also have manufacturer companies that have a say worldwide. We have no problem in producing drive circuits. If we can also supply the technical equipment for the battery management system, we can easily handle any task. As Türkiye, we cannot produce only the electronic components and batteries that are necessary. Apart from that, the mechanical components are seamless, and even the products of most car brands are produced by robots in Türkiye. The localization rate inside the TOGG can be increased. As far as I know, they are working on a battery technology. I find battery technology research and technology transfer in the country very useful.
So, what determines the consumer's interest?
In order for a consumer to use the battery capacity in vehicles for a longer period of time, it is necessary to use high-efficiency electric motors and drive circuits. When we say “new generation electric motors”, we are actually talking about “magnet motors”. The machines with the highest efficiency in electric motors are the machines with magnets. Therefore, they will take up more space in electric vehicles. Each of them offers an advantage over each other in different operating conditions. Some can be controlled at high speeds but take-off slowly, some cannot take-off but can reach very high speeds, while some have less or more operating noise and vibration. For instance, there are 2 electric motors in a Tesla car. One of them is activated more often at take-offs to launch the vehicle. When you reach high speeds, on the other hand, the other motor gradually comes into play. Of course, the motor used, as well as its power and controls are very important. Weight and losses are an important criterion in determining battery sizes.
What are the battery systems used in electric vehicles?
The type of battery you will use actually determines the performance. If a family car is to be manufactured and if you are not worried about acceleration and do not expect sudden power demands, your battery design will be different. If a vehicle like a tractor or construction machine is going to be manufactured, you will demand too much power at low speed. If you want sudden accelerations, your battery should be able to respond to it.
“We have 3 sub-teams as Mechanical, Electrical and Organizational, and they work under the coordination of our team captain and under my supervision. While improving this vehicle for the 2022 Teknofest, we will design another new vehicle for the 2022 Shell Eco marathon London Finals.”
The need for battery technology varies according to the energy needs and energy consumption of vehicles. Accordingly, the operating voltage and current values come into play. Since the batteries are composed of cells, the desired voltage and current are adjusted by connecting the battery cells to each other in series or parallel. We know that you have an “electric vehicle team” at your University.
Can you tell us a little about it?
Originally we were a team participating in the Shell Eco Marathon Races. This year, with the request and support of our Dean, we built a new vehicle and participated in Teknofest. There were 68 high school and 40 university teams at Teknofest this year. The main goal of these teams is not to make commercial products. The main goal is for students to graduate as market-ready staff, having gained experience in this type of design project, and having become equipped and resilient in dealing with problems. They spend a lot of time and try to do a lot of work with low budgets. They are solving problems, and as a result, they are actually learning how to overcome the obstacles that may come up in their professional life. We contribute to the know-how of the country and the university. A useful piece of information or a solution technique found from one of the dozens of teams can carry it to other places. In this type of racing, the vehicles are designed according to the racing rules. In our vehicle, we have made all the designs of the outer shell, visual design, lower body, driver protective cage, mechanical system, battery, driver circuit and electric motor as a team. We also received professional support on issues such as the production of the engine and its placement in the wheel. There are also companies with which we cooperate. Ozdisan Elektronik is an important one of our valuable collaborators. For racing, we use products that meet global safety standards in products such as seat belts and seats. We plan to increase our localization rate in the coming years. These are the things we do actually. We have 3 sub-teams as Mechanical, Electrical and Organizational, and they work under the coordination of our team captain and under my supervision. While improving this vehicle for the 2022 Teknofest, we will design another new vehicle for the 2022 Shell Eco marathon London Finals.
