Posted on April 23, 2017 by Charles Morris
Tesla [NASADQ: TSLA] is on an ongoing quest to improve everything about its products, from components to manufacturing processes to marketing and delivery. Battery technology gets the most media attention, but the company also has a world-class team dedicated to developing better traction motors. Among that team is Konstantinos Laskaris, Tesla’s Chief Motor Design Engineer, who is responsible for the geometry optimization and technology selection of traction motors.
Christian Ruoff, Publisher of the electric vehicle trade magazine Charged, recently had the chance to interview Laskaris for a feature article. Knowing that Laskaris wasn’t at liberty to talk about the specifics of Tesla’s motor technology - often the case when interviewing engineers from major automakers - Christian instead asked him for his general thoughts on the state of the electric motor art.
Laskaris joined Tesla immediately after earning a PhD from the National Technical University of Athens, Greece. “Sometimes I feel like I am in my ninth year of PhD work,” Laskaris told Charged, “which is a good thing. [After joining Tesla] I was not constrained on what I would research. Of course the objective becomes different, and now you need to deliver on a company level and in a more competitive environment, but I would say that the transition was quite smooth.”
Laskaris compares doing research at a university to being an opera singer, whereas working at a company is more like being in a rock band. “Tesla has a unique way of combining opera singers with a rock band,” he explained, “because it really understands the gravity of having research people.”
“Seeing your design going to production in a car like Model S, what could be more rewarding for a motor design engineer?” he added. “Of course the environment sometimes is very competitive. There are so many good engineers that are very involved with what you are doing. It makes sense that it is a bit stressful, but the reward is huge, because the objectives of the company are big. It makes you feel really good about your design work that your work is being appreciated.”
We hear a lot of discussion about battery costs, but motor costs are also heading down as the technology improves. “Motor cost is going lower the more we are optimizing, and as we’re getting more power-dense motors, they get smaller,” said Laskaris. “And if you don’t compromise efficiency with smaller motors and more power density, motor costs will be gradually dropping. The materials in the motors, apart from magnets, have a stable price.”
Tesla also continually strives to improve its manufacturing methods (“the machine that makes the machine”). “We’re making manufacturing cheaper,” says Laskaris. “If we had attempted to make the motors that we are using today twenty years ago, the cost would be much higher, obviously. There are many types of technologies that are coming to play a role here to make motor cost lower.”
Visualizing the electric powertrain as an integrated system is an important factor in reducing costs. “And not only the cost - it will also make a better product, because knowing which operating conditions you want to optimize for, or understanding the system thermally and designing a system that takes advantage of the material capabilities but is not over-designed, is something that comes with experience and more advanced simulation techniques. Optimization is a huge part of making an affordable car that also has amazing performance and range and all of the specifications of interest.”
More and more, engineers are using software to model new motor types, and avoiding building expensive prototypes. “It’s a combination of software capabilities - like modeling motors in an accurate way - and having more advanced modeling tools to represent motors that you don’t want to manufacture, so that you don’t make design mistakes. And then understanding what you want to optimize for, which comes from experience - how a car is driven, what a customer would like. This all leads to understanding what motor to design, and finally the simulation shows you that you have designed the right motor in the end.”
In the battery world, the term “Holy Grail” gets kicked around a lot - researchers are already looking beyond lithium-ion technology to concepts such as solid-state and lithium-air, which they hope will provide the coveted combination of low cost, long life and high energy density. Is there anything comparable to that in the motor world? “Motor technology and motor materials [are] the two components that would make the ultimate traction motor,” said Laskaris. “On the materials side, I would say a core that is plastic - doesn’t have conductivity - and has got huge permeability that you can excite with very low current. [Maybe] it’s not achievable but companies are trying to get towards that direction.”
“From the design perspective, a synchronous separately excited machine that has full flux regulation capability, for example, is sort of an ideal motor for controlling and performance. But it has big manufacturing challenges.”
“Motor designers understand that there are kinds of motors that are designed for manufacturability and feasibility. Then there are also motors that are uncompromised but difficult to manufacture. This is why you see so many motors around. An induction machine, for example, is a gift of nature in the way that it works. Because of the way that you induce eddy currents that beautifully skew the field and create the torque. It’s something unique. You don’t have brushes, don’t have conductors, and the motor has very good characteristics. It has been around for over a century, and the fundamentals have not changed. Of course the methodology that we use has changed a lot because of computers. It’s a smooth motor. It’s a torque-dense motor.”
What advice does Laskaris have for young engineers who want to make an impact on the EV industry? “I would say, don’t underestimate the classic sciences - a good math background, good physics background. If you learn how to use commercial tools for design you will be more ready for the industry, but it’s much better to have a good theoretical background. After that, motor controls is a topic that has a bright future. But I would say that someone who will design good motor controls in the future also needs to understand motors very well. There are people who want to do motor controls before studying electric motors in the first place, and that’s something that I would not recommend. And of course, software engineering and writing code. You will do great if you know how to put your thoughts as an engineer into code. Once you start having your own imagination and ideas it’s a huge advantage.”