Posted on January 18, 2016 by Matt Pressman
Charged Magazine's* Christian Ruoff recently sat down with Tesla Motors' Principal Motor Designer, Konstantinos Laskaris for a fascinating interview. Laskaris is responsible for the electromechanical design and optimization of the Tesla's current and future traction motors. Whereas the internal combustion engine has benefited from millions of man-hours in engineering analysis and refinement over the past century, the collective engineering efforts of the EV (electric vehicle) industry has just begun. Tesla Motors, the EV trailblazer, spends a considerable amount of resources on internal R&D to develop better parts for EVs -- its testing facilities and engineering talent are at the forefront of the industry. In this interview excerpt, we get a first-hand look inside Tesla Motors' unique approach and methodology.
Charged: In general, how are electric motors inherently better for traction applications than combustion engines?
Laskaris: When you simply compare any other high-end conventional car to a Tesla, you see a tremendous difference. This is because of the technology. As for the motor, specifically, there is a huge efficiency advantage, and it is extremely quiet and vibration-free, with very high power density and instantaneous direct response to inputs. All these characteristics of electric motors give an unparalleled performance advantage. This is why it was so important for Tesla, as a company, to break the stereotype that’s been out there for years. People needed to see that performance, efficiency and range can coexist in an EV. The dual-motor powertrain Model S is the fastest sedan that has ever been mass-produced... it spins as fast as 18,000 rpm – speeds that we previously only found in Formula 1 racing vehicles.
Charged: When Tesla decides to change a parameter of its vehicles – like increase the peak battery current or add towing capacity – what does that mean for your motor design team? Do you have an iterative design process?
Laskaris: At our factory in Fremont, we manufacture practically every aspect of the car in-house. We have a motor winding and manufacturing facility, so we can optimize every aspect of our motor manufacturing and control the quality of the product. Also, we can implement changes in production very fast, we’re a very agile company from that perspective. We can generate motor geometries and analyze them with finite element analysis very quickly. We have a big computer cluster with more than 500 core processors that run finite elements – a typical personal computer has two cores, maybe four. That means you can create many virtual models in parallel and do a very large number of calculations.
Charged: There seems to be an endless array of electric motor topologies, architectures and configurations. How do you begin to evaluate and compare all of the possible options?
Laskaris: Understanding exactly what you want a motor to do is the number-one thing for optimizing. You need to know the exact constraints – precisely what you’re optimizing for. Once you know that, you can use advanced computer models to evaluate everything with the same objectives. This gives you a panoramic view of how each motor technology will perform. Then you go and pick the best.
Charged: You have a background in creating the algorithms that allow computers to simulate how a motor will function in the real world. How do these simulations translate into better vehicles?
Laskaris: The mathematical modeling technology, or methodology, that you use is very important and has tremendous impact on the success of electric vehicles. When I say “modeling,” I mean to understand the mathematical principles behind a system and then create software tools that will represent accurately how it will act in the real word. Accurate motor modeling is so important because through it we can evaluate a hypothetical motor before we produce it – the losses, performance capabilities, torque ripple, thermal management, and anything that we are interested in... through good motor modeling, we can achieve the best optimization – which means we can achieve exotic performance without the use of exotic materials and exotic manufacturing methods.