The fastest electric motor in history: 100,000 revolutions per minute to increase the range of electric cars

Researchers at the University of New South Wales, Sydney, recently developed a new electric motor that can turn 100,000 revolutions per minute. The high power density achieved by this new design could help reduce the weight of electric vehicles (EVs) and thus increase their range, the university said in a press release.

EV manufacturers have been looking for ways to solve their cars' range anxiety problems. One way is to increase the size of the battery pack, but that also increases the weight of the vehicle, creating more problems to solve.

Another way is to reduce the weight of the electric motor, and to do this we need to increase its speed. A high-speed rotating motor can be reduced in size, which not only reduces its weight, but also reduces its energy consumption, helping to increase its range when used in an electric vehicle.

Traditionally, built-in permanent magnet synchronous motors (IPMSM), which are used in electric vehicles, have magnets embedded in their rotors to achieve strong torque. However, the low mechanical strength of its iron bridge limits its maximum speed. Using a new rotor topology, researchers at UNSW Sydney not only improved the robustness of the motor, but also reduced the amount of rare earth materials needed to produce it by as much as 70 percent.

The UNSW researchers also used an artificial intelligence (AI)-assisted optimization program that evaluated a wide range of electrical, magnetic, mechanical and thermal aspects to optimize the design of the electric motor. The program, which was developed in-house, evaluated 90 designs and then selected the top 50 percent of them to generate a new design, iterating until the desired optimum was achieved. The final motor used by the researchers was the 120th generation analyzed by the program.

The press release said the final motor had an absolute maximum speed of 100,000 revolutions per minute and a peak power density of 7 kilowatts per kilogram, which is twice the maximum speed record of existing built-in permanent magnet synchronous motors.

The researchers say that if this motor is used in an electric vehicle motor, it will reduce its speed somewhat with the aim of increasing its power - for example, a 200 kW motor with a maximum speed of about 18,000 rpm would be perfectly suited for electric vehicle applications.

In addition to electric vehicles, the motor can be used in large heating, ventilation and air conditioning (HVAC) systems that use high-speed compressors, as well as in high-precision CNC machine tools. The motor can also be deployed inside aircraft engines as an integrated drive generator (IDG) to power electrical systems.

The researchers believe their motor could be commercialized quickly and brought to market sooner than we might expect. According to the researchers, "If an electric car manufacturer like Tesla wanted to use this motor, then I believe it would only take about 6 to 12 months to modify it to their specifications."