This Electric Motor Reaches 100,000 rpm Designed by Artificial Intelligence

The University of New South Wales website reports that graduate students have developed a new motor that achieves up to 100,000 revolutions per minute, setting a new world record. This new design has emerged to reduce the weight of electric vehicles through high power density, achieving increased tram range and significantly reducing manufacturing costs.

What affects the range of electric vehicles?

As new energy vehicles become more popular, consumers are increasingly concerned about the range of electric vehicles. 

The drive of electric vehicles mainly depends on the electric drive system, including the battery, electric drive, and electric control. The function is mainly as the drive system of the electric vehicle, responsible for converting the DC power output from the battery, driving the motor to rotate, and transferring the power to the wheels through the deceleration and torsion of the axle gear system, thus driving the vehicle.

Therefore, the range, on the one hand, mainly depends on the battery energy density and material. 

Battery energy density determines the amount of battery charge, such as ternary lithium battery energy density is higher than lithium iron phosphate, the range is longer, but the safety is lacking.

Another important factor affecting the range is the weight of the car. For example, the power battery can be made large enough, but the greater the weight, the shorter the vehicle range, which requires a balance. 

In addition, wind resistance will also affect the range of electric vehicles. Usually, the wind resistance of cars is less than that of SUVs. Other factors, such as ambient temperature and autonomous driving, can interfere with the range.

At the same time, because it mainly relies on the motor drive, and the motor energy efficiency is very high, it can now reach more than 95%, compared to the fuel start energy efficiency generally of about 30%, which can be considered to have been completely incomparable, but also very energy efficient.

Most pure electric car energy consumption is 110-160Wh/Km, which is 0.396-0.576MJ/Km. However, in actual use, many people will find that the difference between the nominal energy consumption and the actual use of energy consumption is very large. 

The fluctuation of energy consumption is also very large, which can be converted to the electric car range. The nominal value also has a large gap. Even with the most stringent EPA testing standards, there will also be a large deviation.

The difference for fuel cars is around 10%-20%, while electric cars can reach around 50%-100%. For example, the standard electric car can exercise 500KM plus air conditioning in summer. 

It may only run about 400KM. At the same time, in the winter, when the temperature is lower, the range can even be as low as 200KM, and this huge fluctuation is significantly different from fuel cars.

One reason is that the electric motor is highly efficient, leading to very sensitive energy consumption. This is well understood. For example, many electric cars have single-stage gearboxes, so as the vehicle speed changes, the motor speed also changes. The motor speed is assumed to be 0-8000rpm (maximum speed is 120km/h).

 The best thermal efficiency range of the motor is not on the daily driving speed. Still, the middle and high speed, so the efficiency range in daily driving will probably fluctuate between 60-90%, and the comprehensive whole vehicle energy consumption will fluctuate around 30%-40%.

And, due to the characteristics of the electric motor, the 100km acceleration time is already comparable to the luxury level of fuel cars, and the stronger the dynamics, the greater the 100km electric consumption. 

The multiple starts and stops in urban areas will also accelerate energy consumption. However, many electric cars have been installed with energy recovery systems, which can recover the vehicle's kinetic energy when braking and reuse it for driving to save the loss of electricity.

Therefore, battery capacity, materials, wind resistance, and automatic driving will objectively affect the range performance of electric vehicles. In contrast, the impact of electric motors on electric vehicle range is relatively subjective and depends on the driver's driving habits.

How the 100,000 rpm motor was designed

The 100,000 revolutions per minute motor developed by the University of New South Wales was engineered to increase the range performance of electric vehicles through artificial intelligence technology.

The same method of increasing the weight of the battery will reduce the range of the electric car; conversely, reducing the size of the devices in the car will increase the range with the same battery capacity. 

Therefore, many cars use new materials for the frame or use materials such as SiC to improve the range.

Due to their ultra-high speed, the new electric motors allow the motors to be reduced in size, reducing weight and greatly reducing power consumption. 

Meanwhile, electric drive systems in electric vehicles use built-in permanent magnet synchronous motors (IPMSM), in which magnets are embedded in the rotor to generate huge torque.

However, today's IPMSMs have low mechanical strength due to the laminated cores consisting of thin metal sections or sintered sections connected to the rotor, thus limiting the speed of the electrons. By using a new rotor topology, the researchers have further improved the stability of the motor while also allowing a 70% reduction in the rare earth required for motor production.

The new design is based primarily on the engineering characteristics of the Gyopo railroad bridge, a double-tethered arch structure in Korea, and curve-conforming mechanical stress distribution techniques. 

The result allows the new motor to achieve a power density of nearly 7kW per kilogram, twice that of the existing laminated IPMSM, greatly enhancing the performance of electric vehicles.

Thanks to the significantly enhanced rotor structure, the mechanical safety factor of the new high-speed motor can reach 1.5-2 times that of currently marketed motors, and it is inferred that its service life will be longer than that of ordinary motors.

If put on the market, this new motor will soon be able to meet with consumers. 

According to the research team, the manufacturers represented by Tesla want to use this motor, the specification modification and commissioning only need to take 6-12 months.This new motor can provide more range for electric vehicles than the current electric motor. 

The team predicts that by expanding and optimizing the motor design for electric applications, the new motor is expected to be 10-20% lighter and 2%-5% more efficient than similar products in the market.

And the inverter also benefits from the high speed and becomes lighter and smaller. The weight reduction and energy efficiency improvement are expected to extend the range of electric vehicles by 5-10%.

Notably, the new motor was designed using an artificial intelligence-assisted optimization program to optimize the motor design in terms of electrical, magnetic, mechanical, and thermal performance. 

The research team evaluated 90 scenarios and then selected the top 50% of them to generate a new design until the current best result. This one is already the 120th generation of products analyzed by the program.

Summary

This newly designed electric motor has the features of high speed, long life, low cost, and lightweight but also can further help electric vehicles save internal space and reduce the body's overall weight, thus achieving the effect of range enhancement. 

A highlight is that the research team has optimized and iterated the relevant design several times with the assistance of artificial intelligence until the best result is reached. 

This is not the only innovation of the electric motor product but another fruitful application of AI technology on the ground.

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