68 motor’s performance, which we can use for further development.” Our second motor developer notes there has been a drive towards systemlevel optimisation capabilities in the software, enabled by the integration of different tools. “With MotorCAD, for instance, you can design your motor and then bring it into Matlab, where you can then look at optimising your system,” its expert says. “For example, I could design a 99% efficient motor, but if I were to pair it with a controller that has to switch at an excessively high frequency, it is then going to have such large losses in the inverter that overall the system would be a lot worse.” This is particularly helpful as customers are increasingly asking for turnkey solutions. “A lot of the change in my job over the last couple of years has been in offering full-package solutions – so, motor, inverter, gearbox and even battery packs, working with other companies.” Integrating individual tools with one another allows for multiphysics analyses (in Ansys Workbench, for example), which our third motor developer regards as a major improvement in design and engineering software. Its expert notes this has greatly reduced design cycle times and improved the optimisation of designs across independent domains. He credits Ansys OptiSLang with easing the integration of optimisation into the design simulation loop, offering new ways to ensure local optima are avoided. (With optimisation problems, local optima are solutions that are better than neighbouring ones, but not necessarily the best overall. The software enables thorough exploration of the design space, increasing the likelihood of finding a global optimum solution.) The expert also cites the emergence of cloud-based, high-performance computing (HPC) as a key enabler of the use of advanced simulation tools in design and development, with agility bringing agility to the process. Creating prototypes Moving on to hardware, companies that provide prototyping services often make their own tools. For one organisation specialising in building prototype e-machine rotor and stator lamination stacks from customers’ CAD files, this is almost a routine task. “For every item that we have to manufacture, we have to engineer a new device that works as an aligning and pressing tool at the same time. The laminations are placed one-by-one into the tool and pressed down, and then they can go into an oven if they are bonded using Blacklack, or onto a welding station to create a solid stack,” its expert says. Companies emphasise different aspects of prototyping. One of the motor manufacturers we consulted says they start with an analysis of customer requirements to see whether an existing design meets them or comes close to doing so. An expert from another motor manufacturer follows his assessment of customer requirements by establishing and communicating basic assumptions. “It’s really good to clearly write down what I’m assuming so it can be revisited later, because otherwise some important things you think should be obvious to a customer might not be.” Some high-level initial analytical equations might then be run for sizing the motor, followed by an initial concept review in which you would evaluate rotor topology. “Then you would use something like Ansys MotorCad to analyse feasibility and validate your sizing equations,” he adds. Next comes mechanical, electrical and thermal optimisation in 2D and then 3D. Mechanical optimisation of the laminations would be done with a 2D tool, but some losses, such as those associated with eddy currents in the stack or ohmic losses in the end-windings, can be calculated more accurately with 3D tools, he says. When the time comes to make prototype hardware, the company will 3D-print a stator to check that the winding pattern generated in the CAD system can be wound in reality. While most can, it is not always the case. For example, if the motor uses stranded wire there is a degree of uncertainty and the engineers consult with experienced winding workers, who might change the order in which the coils are wound or perhaps identify an opportunity to increase the slot-fill factor. An expert from a different motor developer says the company was starting to make the prototyping of new e-motor designs easier, better and faster. “To achieve this, we rely on the targeted use of 3D printing to realise complex designs without the use of complicated tools,” he says. Focus | Motor development and manufacturing July/August 2024 | E-Mobility Engineering AF 140 axial-flux motor from Turntide, showing advanced features such as stators made from a single, thin lamination, and a composite rotor with embedded, permanent magnets secured with carbon-fibre tape (Image courtesy of Turntide)
RkJQdWJsaXNoZXIy MjI2Mzk4