Last month CTO Tim Woolmer met with Rory Jackson from E-Mobility Engineering and discussed the origins of the YASA Axial Flux Motor, and how a complex algorithm and simple question led to the evolution of this ground-breaking electric propulsion solution, and mass production of the motors in the UK & Germany.
"When I was in my undergraduate years, Oxford University had this extraordinary algorithm for assigning challenging projects to fourth-year engineering students, but when it had to choose one for me, the algorithm broke; so, very unusually, I was told that I had to decide and write my own project brief,” Woolmer recounts.
“I took some time to think about what I was really interested in. This was 2003, and I soon found myself asking why there weren’t any electric cars."
Woolmer soon found himself focusing on traction systems for upcoming EVs and HEVs for his PhD project. Qualities he was particularly interested in were how they had been designed to reduce weight, and to increase both efficiency and manufacturability.
"That got me looking into electric motor structures, topologies, and components that could reduce their weight and size for automotive applications"
His supervisor pointed him towards axial-flux motors, suspecting that their shape and dynamics would work better with a segmented topology than radial-flux machines. Subsequent research led to Woolmer’s concept for what today remains the fundamental design philosophy of YASA’s motors.
“I stumbled upon this concept early in my PhD, so I got three years to build motors and inverters, and try them in cars. They were far from perfect, because I was, after all, just a PhD student without the massive resources of a real manufacturer, but, as stated in the final report, we achieved around 40-50 kW of continuous power from a 12 kg motor.
“That meant around 3-4 kW/kg in an e-motor in 2009, compared with around 0.6 kW/kg in a Toyota Prius’ motor, so we saw there was a huge difference this technology could make in the market, and we gained some seed money from the university to optimise our prototype into something more akin to a proper product. We ended up calling that product the YASA 750, and we still sell it today, 15 years later.”
Read the full interview with Tim & Rory at E-Mobility Engineering
