Shulou(Shulou.com)11/24 Report--

Someone else's 17-year-old has been able to invent motors that could change the streetcar industry.

Robert Sansone, from Piersburg, Florida, has developed a new prototype of synchronous reluctance motor, which is made of 3D printed plastic, copper wire and steel rotors.

Source: the biggest highlight of this new type of motor is that it does not need to use rare earth materials and has greater torque and efficiency than existing similar motors.

You know, most tram motors need magnets made of rare earth elements, which are environmentally and economically expensive to extract, costing hundreds of dollars per kilogram of rare earths.

Once the new motor breaks away from the restriction of rare elements, it will undoubtedly improve in terms of cost and economy.

With this prototype, which does not require rare earth magnets, Sang Song won the first prize in this year's largest international STEM competition for middle school students, the Regenerative International Science and Engineering Grand Prix (ISEF), and won a prize of US $75000 (about 519000 yuan).

Sang Song, the child of others, is like a born engineer who first made electronic manipulators. He also built go-kart cars with a speed of more than 70 miles per hour, and completed at least 60 projects in his spare time.

Source: after watching a video of the advantages and disadvantages of electric cars, Smithsonion found that the motors of most electric cars need magnets made of rare earth elements.

However, magnets are not readily available, and it is an important factor that undermines the sustainability of electric vehicles, including Tesla's use of permanent magnets in his motors.

The sustainability of permanent magnet motor itself is poor, coupled with a wide range of applications. In the long run, it is not conducive to the sustainable development of the environment.

At present, synchronous reluctance motors, which do not use rare earth materials, are mostly suitable for pumps and fans because of their own power limitations, but can not be used in electric vehicles, so Sansong began to find ways to improve motor performance.

Source: AnElectricMotor means that even without rare earth magnets, synchronous reluctance motors can have the same efficiency as permanent magnet motors, or even better.

"once I have this idea, I have to do some prototyping to see if it really works." Without conditions, Sansong began to try to make a small prototype out of a 3D printer.

Sanson's approach was also endorsed by Heath Hofmann, a professor of electrical and computer engineering at the University of Michigan.

"Sansong is looking at things in the right way, and this idea will be the next big thing in the [motor] industry." Hoffman believes that the materials of synchronous reluctance motors are cheap, but the machines are complex and very difficult to make. Using 3D printing technology, motor manufacturing can be made more easily.

Facts have proved that Sangsong has created a prototype of a new type of synchronous reluctance motor with better performance than permanent magnet motor through a series of operations.

Source: AutoEvoluition, as a student at Piersburg Central High School, Sanson's dream is to get into MIT. The prize money he received from ISEF will also be used for college tuition.

Interestingly, Sang Song did not plan to compete with this motor at first. When he learned that he would help him finish his paper after the competition, he decided to participate.

Next, Sang Song will apply for a patent for his motor and will negotiate with the car company after completing the test. He hopes that one day his motor will become the motor of choice for electric vehicles.

02 what kind of motor is this? The working principle of the motor is the effect of the magnetic field on the current, which makes the motor rotate.

In a permanent magnet motor, the magnetic field produced by the magnet is attracted by the opposite pole of the rotating magnetic field, which makes the motor rotate.

However, synchronous reluctance motor (Synchronous Reluctance Motor) does not need a magnet, it is essentially a synchronous motor with magnetoresistive properties. Working through the gap between the steel rotor and the air, torque will be generated when the rotor rotates with the rotating magnetic field.

(section of synchronous reluctance motor) Source: the greater the salient pole ratio of WatElectrical or the magnetic difference between steel rotor and non-magnetic air gap, the greater the torque.

Sang Song's genius idea is shown here, and his design has a deeper way of thinking. He thinks that another magnetic field can be integrated into the motor and the air gap can be replaced by the secondary magnetic field instead of using the air gap. This can increase the salient pole ratio of the motor, resulting in greater torque.

Source: AutoEvolution he verified his results in the second experiment.

In its newly designed motor, at 300 revolutions per minute, the torque increased by 39% and the efficiency increased by 31%. At 750 revolutions per minute, the efficiency increased by 37%.

However, Sanson did not test for higher revolutions because the plastic components would overheat and melt. "I can't test it at higher revolutions because the plastic will overheat, such as one of the prototypes melted on my desk."

By contrast, Tesla's Model S motor can rotate at 18000 revolutions per minute.

In addition, Sang Song also conducted an experiment, which excluded other variables, confirming that the improvement of torque and efficiency was directly related to his design.

Source: if AutoEvolution can give him better, more heat-resistant materials, the efficiency may be more obvious.

In fact, his design has other components, but can not disclose more details, he said that he hopes to apply for a patent for the technology in the future. But before applying for a technology patent, the details are kept secret.

Of course, the process is not so easy, before completing the design, he has made many prototypes. "I don't have a mentor to help me. Every time the motor fails, I have to do a lot of research and try to solve the problem of the mistake. But finally, on the 15th motor, I finally made a working prototype."

Source: Hack Club so Sanson is now working on his 16th prototype and plans to make a prototype of a stronger, heat-resistant material to test higher revolutions.

03 permanent magnet electrical opportunities will not be replaced? The motor types of new energy vehicles are mainly divided into DC motor, AC asynchronous motor, permanent magnet synchronous motor and switched reluctance motor. At present, most of the motors in the market are permanent magnet synchronous motors.

Source: AEM permanent magnet synchronous motor is mainly composed of two parts, one is the shell, because it remains static, so it is called stator, a rotor, usually rotates inside the stator, sometimes outside.

Source: Linquip, a permanent magnet made of rare earths, can create a continuous magnetic field on its own, resulting in a high torque density, but the cost alone has dissuaded many people. From June 2020 to August 2021, for example, the price of neodymium, the most important element in magnets, directly doubled.

Source: Linquip in this context, not only Sansong, many startups and professionals are also actively promoting the innovation of traditional motors.

For example, Magnax, a Belgian start-up, made an innovation by rethinking the electromagnetic interaction in the motor, using an unyoked axial flow design.

Through this design, the weight, size and cost of the motor can be reduced. And most importantly, the stator needs only about 60% copper, and the rotor only needs about 80% magnetic material.

This also makes the power density of the motor four times higher than that of the traditional internal combustion engine. The company says it plans to start producing 25000 motors a year by 2022.

Source: Magnax in addition, other startups, including Powdermet and Turntide Technologies, are also designing a motor that does not rely on permanent magnets. Not only startups, including mainframe manufacturers such as BMW, Toyota and Volkswagen, are also looking for ways to reduce the use of permanent magnets in motors.

Source: one trend at Stanford Magnets is that motors designed by these companies, including those designed by Sansone, are abandoning a component that most motors have-permanent magnets.

Although many teams are promoting motor innovation, there are also different voices.

Ayman EL-Refaie, a professor of electrical and computer engineering at Marquette University University in Milwaukee, Wisconsin, is working with General Motors to develop a rare earth-free transmission system. Although he has found potential demand for rare earth-free permanent magnet motors, it is still difficult to achieve this goal.

Source: Pmlindia in his view, it is not easy to remove the design of permanent magnets, and when increasing the size of the machine to make up for power loss, there is a risk of permanent demagnetization using magnets without rare earth materials.

Martin Doppelbauer, a professor of hybrid electric vehicles at the Karlsruhe Institute of Technology in Germany, is more direct, saying that there is no trend of leaving the permanent magnet because the permanent magnet has the highest power density and the best performance, and most enterprises will use it.

"these companies are developing alternatives to permanent magnet motors, but they will not be needed until the prices of rare earths rise again."

This article is from the official account of Wechat: Chaodian Lab (ID:SuperEV-Lab), author: Wang Lei

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