里卡多无稀土铝电机（Alumotor）

英国里卡多（Ricardo）开发了铝电机概念，该概念不仅消除了稀土元素，而且最大限度地减少了铜的使用。Ricardo的项目范围还包括电机的工业概念及其与EDU的集成。

从性能和效率的角度来看，永磁电机很难被击败，但价格昂贵，不太可持续，而且对供应链问题很敏感。

制造一种接近PMSM功率密度的无稀土电机将是一项艰巨的任务，但Ricardo的解决方案融合了现有技术和新颖的工程来实现这一目标。

铝电机是一种同步磁阻电机，其布局是根据其卓越的扭矩输出潜力而选择的

同步磁阻电机的控制方式非常不同。可以像普通的永磁电机一样运行，不需要稀土元素或铜绕组，重要的是，它非常坚固。没有什么真正会随着时间的推移而退化的，不像永磁电机那样。    

铝电机可以在更高的温度下运行。只有钢和铝，没有任何东西会受到热量的影响（在合理范围内）。唯一的具体考虑是绕组的绝缘材料，但也有可用的解决方案。只要你选择了合适的材料，就没问题。大多数电机的温度不会超过180°C，并使用H级绝缘，但可以使用220°C或更高的C级绝缘。其优点是，可以在不增加尺寸的情况下更热地运行机器并提高功率密度。

此外，铝电机设计为在800V下运行，这意味着更低的电流，从而减少损耗。同样，这可以增加功率密度。

端部绕组采用喷雾冷却

一个突出的特点是使用了铝绕组。铝比铜更可持续，更便宜，更容易获得。通过里卡多开发的技术，能够在不影响功率密度的情况下使用它，例如在更高的电压和温度下运行。

除了使用铝之外，该设计的另一个新颖特征是转子拓扑结构和引导磁通量的磁通引导器的形式。采用空洞，只是空气。Ricardo也有一个变体正在开发中，其中这些空隙用磁性材料填充。对于需要较低功率密度（但高于标准铝电机）的机器，这些可以是铁氧体磁体。Ricardo正在与合作伙伴合作开发磁通密度与稀土磁体相同但由可持续材料制成的材料。这一发展将使铝电机的设计与市场上最好的高性能机器相媲美。

已经进行了大量仔细的实验来计算参数，例如确保弯曲的方式不会使搪瓷绝缘层破裂

铝电机难题的最后一个是冷却系统，它确保冷却液可以直接放置在产生最大热量的地方。转子和定子都具有冷却通道，同时喷射也确保冷却液可以被引导到绕组上。合作伙伴优化

Alumotor是由Ricardo领导的英国Alumoto组织联合开发的，合作伙伴包括Aspire Engineering, Brandauer, Warwick Manufacturing Group at the University of Warwick, Phoenix Scientific Industries and Global Technologies Racing (GTR)。    

铝电机的3D打印模型，显示转子冷却通道

与使用铜绕组的普通电机相比，存在一些制造差异。例如，当形成发夹时，铝更软，并显示出更大程度的回弹，但这可以在现有的工艺技术中得到满足。

绕组的焊接也需要与铜不同的方法，但同样，也有可以适应的既定工艺。

早期的原型证明了这一概念，2022年，里卡多与其合作伙伴在Innovate UK的“推动电气革命”挑战基金的支持下，开始开发当前版本的Alumotor，该基金涵盖了实际的电机设计和配套的供应链。

里卡多并没有立即将Alumotor作为乘用车市场的目标。相反，它将目光投向LCV和非公路市场，这将从其价格实惠和坚固耐用的特性中受益最多。

https://www./features/supplier-interview-ricardos-rare-earth-free-alumotor.html

Supplier interview: Ricardo’s rare earth free Alumotor

By LAWRENCE BUTCHER

December 23, 2023

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Recent years have brought into harsh focus how fragile automotive supply chains can be. Spanning the globe, seemingly unrelated geopolitical events can have a huge impact on the availability of key components, placing the industry’s just-in-time production models in peril. Although semiconductors have recently taken the limelight, the reliance of most high-performance automotive traction motors on rare earth magnets has also come under scrutiny. Not only are the materials themselves subject to supply constraints but there is also an increasingly vocal conversation underway regarding their sustainability from both an environmental and a social responsibility angle.

The result is a growing requirement for power-dense motors that forgo such magnets. This is what was behind UK-based Ricardo’s development of the Alumotor concept, which not only does away with rare earths but also minimizes the use of copper. Ricardo’s project scope also includes industrial concepts for the motor and its integration into an EDU. APTI spoke to the company’s automotive and industrial technical authority head, Dr Jay Al-Tayie, and Simon Meredith, PEMD and transmission project engineer for performance products, to find out more about this novel motor architecture.    

“The project started three years ago, when we were looking for a sustainable motor solution for the UK market,” says Al-Tayie. Permanent magnet motors are hard to beat from a performance and efficiency perspective “but they are expensive, not very sustainable and sensitive to supply chain issues,” he adds.

Making a rare-earth-free motor that comes close to the power density of PMSMs was going to be a tough undertaking, but Ricardo’s solution blends existing technology and novel engineering to achieve just that.

The Alumotor is a synchronous reluctance machine, a layout chosen for its potential for excellent torque output. “With switched reluctance machines, you obviously have to switch the phases, which is why they are noisy from both an audible and efficiency perspective,” explains Al-Tayie. “At low speed they are also quite hard to control and not very efficient. A synchronous reluctance machine is controlled very differently. You can run it very much like a normal permanent magnet machine, you don’t need rare earth elements or copper windings and, importantly, it is very robust. There is nothing really to degrade over time, unlike a PM machine where you may lose performance due to thermal and coercivity impacts.”    

It is this robustness that means the Alumotor can be run at higher temperatures. With just steel and aluminum in the construction, there is nothing to be affected by heat (within reason). The only specific consideration is the insulation material coating the windings, but solutions are available. “As long as you select the right material, it is fine,” explains Al-Tayie. “Most motors do not go beyond 180°C and use class-H insulation, but you can go to class C, which is 220°C or higher. The advantage is you can run the machine hotter and increase power density without upping the size.” Furthermore, the Alumotor is designed to run at 800V, which means lower current and thus reduced losses. “Again, this lets you increase the power density,” he adds.    

The end windings are spray cooled    

One of the standout features, and giving the motor its name, is the use of aluminum windings. “People ask, why aluminum? Because it’s more sustainable than copper, it’s cheaper and more readily available. With the technology we have developed we are able to use it without compromising power density, running at higher voltages and higher temperatures, for example,” says Al-Tayie.

Another novel feature of the design, beyond the use of aluminum, is the rotor topology and the form of the flux guides that direct the magnetic flux. “They are voids, just air,” says Al-Tayie. However, Ricardo also has a variant in development where these voids are filled with magnetic material. For machines that require lower power densities (but higher than the standard Alumotor), these could be ferrite magnets. Ricardo is working with partners on the development of materials with the same flux density as rare earth magnets but made from sustainable materials. This development would make the Alumotor design comparable to the best high-performance machines on the market.    

There has been a lot of careful experimentation to work out the parameters, such as making sure the bends are made in such a way as to not crack the enamel insulation          
SIMON MEREDITH, PEMD AND TRANSMISSION PROJECT ENGINEER FOR PERFORMANCE PRODUCTS

The final piece in the Alumotor puzzle is the cooling system, which ensures that coolant can be placed directly where the greatest heat is generated. Both the rotor and the stator feature cooling channels, while spray jets also ensure the (dielectric) coolant can be directed onto the windings. “We are hitting it from every angle,” says Meredith. “We have conducted a lot of computational fluid dynamics and analysis work, which has given us a lot of cooling opportunities for the rotor and stator and means we can run them as hard as possible.”

Partner optimization          
The Alumotor was developed as a joint effort by the UK-Alumotor consortium, led by Ricardo and involving partners Aspire Engineering, Brandauer, Warwick Manufacturing Group at the University of Warwick, Phoenix Scientific Industries and Global Technologies Racing (GTR). The breadth of expertise across the consortium has been a key enabler for the project. For example, Meredith highlights the work done in conjunction with Brandauer, which manufactures the steel laminations: “We’ve done a lot of technical work to make sure that the rotor is structurally sound and not going to break apart under its own stresses. These have been really delicately and intricately worked out and there has been a lot of collaboration with Brandauer on the stamping to make sure they can actually be manufactured. It’s been really good working with the consortium, to have those experts that you can lean on to understand what we can and can’t do and how feasible it is to manufacture things.”    

A 3D printed model of the Alumotor showing the rotor cooling channels    

There are some manufacturing differences compared with a regular motor using copper windings. For example, the aluminum is softer and displays a greater level of spring-back when the hairpins are formed, but this can be accommodated within existing process technologies. “There has been a lot of careful experimentation to work out the parameters, such as making sure the bends are made in such a way as to not crack the enamel insulation,” notes Meredith. The welding of the windings also needs a different approach from copper, but again, there are established processes that can be adapted.

Full-circle approach          
Early prototypes proved the concept and in 2022 Ricardo, in conjunction with its partners, commenced development of the current iteration of Alumotor, with support from Innovate UK’s Driving the Electric Revolution challenge fund, encompassing both the actual motor design and the supporting supply chain.

Ricardo is not immediately targeting the passenger car market with the Alumotor. Instead, it is looking to the LCV and off-highway markets, which would benefit most from its affordable and rugged characteristics. “While everyone is electrifying and everyone is going after copper and rare earth magnets, this is a great opportunity for an OEM customer to diversify and not get hit by the price rises that there are going to be,” concludes Meredith.

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