Researchers at the University of New South Wales in Australia have developed a new electric motor that can achieve 100,000 revolutions per minute, according to the university’s website. The high power density achieved by the new design could help reduce the weight of electric vehicles, thereby increasing their range. Electric vehicle manufacturers around the world have been looking for solutions to the range of challenges of battery-powered vehicles. One option is to increase the size of the battery pack, but this also increases the weight of the vehicle and creates more problems to solve.
The new motor designed and built by the UNSW team is an improvement on the existing IPMSM (built-in permanent magnet synchronous motor), which is primarily used for traction drives in electric vehicles. Image credit: Guoyo Chu/University of New South Wales
Another option is to reduce the weight of the motor. A motor that spins at high speed can be reduced in size, which not only reduces weight but also reduces energy consumption and can increase the range of an electric vehicle with the same battery pack.
Conventional built-in permanent magnet synchronous motors (IPMSM) are used in electric vehicle traction drives, where magnets are embedded in the rotor to produce powerful torque. Existing IPMSMs suffer from low mechanical strength due to the thin iron bridge in the rotor, which limits their maximum speed. The researchers used a new rotor topology that not only improved the robustness of the motor but also reduced the number of rare earth materials required to produce the motor by 70%.
Using an artificial intelligence-assisted optimization program, the UNSW researchers evaluated various aspects of electrical, magnetic, mechanical and thermal performance to optimize the motor design.
The team evaluated 90 design options, then selected the top 50% of these to generate a new design and repeated the iterative process until the desired optimum was achieved. The last motor design, the 120th generation analyzed by the program, ultimately achieved an absolute maximum speed of 100,000 revolutions per minute and a peak power density of 7 kilowatts per kilogram, twice the high-speed record of existing laminated IPMSMs, making it the fastest IPMSM ever built.
In addition to electric vehicles, the motor can also be used in large heating, ventilation and air conditioning systems using high-speed compressors and high-precision CNC machines, or as an integrated drive generator deployed inside aircraft engines to power electrical systems.
The new motor also offers significant cost advantages over existing technologies. Most high-speed motors use a sleeve to strengthen the rotor, which is usually made of high-cost materials such as titanium or carbon fiber. The new rotor, on the other hand, is so mechanically robust that it does not require a sleeve and uses only about 30 percent rare earth materials, resulting in a significant reduction in cost and thus making the high-performance motor more environmentally friendly and affordable.
