UNSW staff develops new very-high-speed IPMSM motor with improved energy density for EVs; new rotor topology

Engineers on the College of New South Wales (UNSW), Australia, have built a brand new high-speed motor which has the potential to extend the vary of electrical autos. The utmost energy and velocity (100,000 rpm) achieved by this novel motor have efficiently exceeded and doubled the prevailing high-speed document of laminated IPMSMs (Inside Everlasting Magnet Synchronous Motor), making it the world’s quickest IPMSM ever constructed with commercialized lamination supplies.

The motor is ready to produce a really excessive energy density, which is helpful for EVs in lowering general weight and subsequently elevated vary for any given cost.


The brand new know-how, developed by a staff headed by Affiliate Professor Rukmi Dutta and Dr Guoyu Chu from the UNSW College of Electrical Engineering and Telecommunications, is an enchancment on current IPMSMs, that are predominantly utilized in traction drive of electrical autos.

An IPMSM sort motor has magnets embedded inside its rotors to create sturdy torque for an prolonged velocity vary. Nevertheless, current IPMSMs endure from low mechanical power attributable to skinny iron bridges of their rotors, which limits their most velocity.

The UNSW staff have patented a brand new rotor topology which considerably improves robustness, whereas additionally lowering the quantity of uncommon earth supplies per unit energy manufacturing.

The brand new design relies on the engineering properties of the Gyopo rail bridge, a double-tied arch construction in South Korea, in addition to a compound-curve-based mechanical stress distribution approach.

One of many tendencies for electrical autos is for them to have motors which rotate at greater speeds. Each EV producer is making an attempt to develop high-speed motors and the reason being that the character of the legislation of physics then lets you shrink the dimensions of that machine. And with a smaller machine, it weighs much less and consumes much less vitality and subsequently that offers the car an extended vary.

With this analysis challenge we’ve got tried to realize absolutely the most velocity, and we’ve got recorded over 100,000 revolutions per minute and the height energy density is round 7kW per kilogram. For an electrical car motor we might truly cut back the velocity considerably, however that additionally will increase its energy. We are able to scale and optimize to offer energy and velocity in a given vary—for instance, a 200kW motor with a most velocity of round 18,000 rpm that completely fits EV functions.

We have now our personal machine design software program package deal the place we are able to enter the necessities of velocity, or energy density and run the system for a few weeks and it provides us the optimum design that satisfies these wants.

—Dr Chu


The design of the brand new IPMSM motor took its ispiration from the double-tied arch rail bridge in Gyopo, South Korea. Picture from Dr Guoyo Chu

The brand new IPMSM prototype motor was developed utilizing the UNSW staff’s AI-assisted optimization program which evaluated a collection of designs for a variety of various bodily facets: electrical, magnetic, mechanical and thermal. This system evaluates 90 potential designs, then selects the most effective 50% of choices to generate a brand new vary of designs and so forth, till the optimum is achieved. The ultimate motor is the 120th technology analyzed by this system.

The UNSW staff’s new motor additionally provides a big value benefit over current know-how and makes use of much less uncommon earth supplies resembling neodymium.

Most high-speed motors use a sleeve to strengthen the rotors and that sleeve is normally product of high-cost materials resembling titanium or carbon fibre. The sleeve itself may be very costly and in addition must be exactly fitted and that will increase the manufacturing value of the motor.

Our rotors have superb mechanical robustness, so we don’t want that sleeve, which reduces the manufacturing value. And we solely use round 30% of uncommon earth supplies, which features a huge discount within the materials value—thus making our high-performance motors extra environmentally pleasant and reasonably priced.

—Dr Chu