High power density, low losses, and very dynamic behavior – these were the require­ments that a customer in the auto­mo­tive industry placed on the elec­tron­i­cally commu­tated external rotor motor for their exhaust aftertreat­ment pump system. “Our stan­dard motor was not designed for this,” says Frank Jeske, Head of Motor and System Devel­op­ment at ebm-papst in St. Georgen. “A few modi­fi­ca­tions to the motor were required for the appli­ca­tion.”

In the past, for devel­op­ment projects like this, ebm-papst used to work simul­ta­ne­ously with different soft­ware tools which came closer and closer to the solu­tion in repeated calcu­la­tion runs. Using this, the engi­neers designed a prelim­i­nary version and built the first samples on this basis. They tested them, changed para­me­ters, and devel­oped new prelim­i­nary versions and samples until the motor met the desired require­ments at some point. “The motor under­went various opti­miza­tion loops,” explains Jeske. “That cost a lot of time and money.” So the motor working group at ebm-papst started looking for better devel­op­ment methods.

“The program’s knowl­edge grows. If we have a follow-up project, we can use the data and expe­ri­ence gained from this project and reuse parts.”

Frank Jeske, Head of Motor and System Devel­op­ment at ebm-papst

Illus­tra­tion of the stator of the motor with opti­miza­tions. (Photo | Linz Center of Mecha­tronics)

The St. Georgen site found the solu­tion for indus­trial and auto­mo­tive appli­ca­tions in the SyMSpace system devel­oped by the Linz Center of Mecha­tronics. The program can inde­pen­dently control third-party soft­ware such as CAD, finite element solvers, and dynamic simu­la­tion tools remotely, thus combining all the neces­sary tools in one program. “Now we create models and tell the program which para­me­ters these should be opti­mized for – for example for minimum losses. It then does the calcu­la­tions itself – for example over the weekend – and if every­thing works out, we can already create samples on Monday,” says Jeske.

As a result, the customer receives reli­able inter­me­diate results faster, making adap­ta­tions easier and ulti­mately creating a better product. This is because the calcu­lated optimum is more accu­rate than getting closer to the require­ments using sample loops, provided that the models reflect reality to a precise enough extent. “The major advan­tage is that the program’s knowl­edge grows. If we have a follow-up project, we can use the data and expe­ri­ence gained from this project and reuse parts. This means we reach our goal faster.”

Future projects: Digital twin and thermal modeling

Since the 90s, ebm-papst has been working closely with the Linz Center of Mecha­tronics and the Institut für elek­trische Antriebe und Leis­tungse­lek­tronik (Insti­tute for Elec­trical Drives and Power Elec­tronics) at the Johannes Kepler Univer­sity of Linz on the opti­miza­tion of systems. Both are currently working with other compa­nies on the topic of digital twins as part of a publicly supported project. In future, a simu­la­tion model is to be provided to the customer in advance. They will be able to use this to inte­grate the func­tion­ality of the motor or the complete drive system into their system as a digital version. In this way, they can pre-simu­late the behavior of the drive solu­tion, such as speed, torque, thermal char­ac­ter­is­tics, losses and so on, and design their surround­ings applic­ably before they have the product in their own hands.

The SyMSpace Opti­mizer compares losses in the motor and the costs of imple­men­ta­tion. The devel­oper can then choose the ideal combi­na­tion. (Photo | Linz Center of Mecha­tronics)

The opti­miza­tion of simu­la­tion models in SyMSpace was already the first step here. A key sub-aspect of this is thermal modeling. In indus­trial drive tech­nology, there are often unfore­see­able cycles with fast start-up, rapid braking, sudden changes in torque, or speed fluc­tu­a­tions. This makes simu­la­tion diffi­cult because it is compli­cated to simu­late how the active compo­nents of the motor heat up. This is set to change in the future: Together with the Linz Center of Mecha­tronics, ebm-papst is gener­ating a thermal model for antic­i­pating the loads that may arise in prac­tice following cali­bra­tion, using a target hard­ware connec­tion. This means the company will soon be able to satisfy customer require­ments in indus­trial drive tech­nology even more precisely.