Creating a series of next-generation 25 to 250 kW e-drives in five years

Developing next-generation e-drives

Manufacturing electric vehicles (EVs) and electric drive (e-drive) systems has diverse and complex challenges, including raw material sourcing, driving range, performance, longevity and safety issues. In many cases, there are also issues concerning public acceptance of charging and changing driving habits.

Headquartered in France, Emotors, formed in 2018 as a joint venture between Stellantis and Nidec Leroy-Somer, is an independent and innovative e-drive manufacturer trying to overcome these challenges.

“A key part of our knowledge is not just about good development – being able to design and prototype next-generation e-drives for our EV customers – but also manufacturing them en masse,” says Cédric Plasse, chief technology officer (CTO) at Emotors. “This is where platform development, a very well-known strategy in automotive, helps us be competitive.”

To help overcome these challenges and achieve their goals, Emotors enlisted the help of Siemens Digital Industries Software, adopting its Simcenter™ software, which is part of the Siemens Xcelerator business platform of software, hardware and services.

Overcoming acoustic challenges for developing e-drives

One of the many challenges facing Emotors engineers is meeting stringent and evolving specifications, especially for noise, vibration and harshness (NVH) acoustic performance. Since vehicles are more digital than they used to be, NVH testing and EV acoustics might not seem so important.

However, there was a time when almost every driver was accustomed to the noise of internal combustion engines (ICEs). At that time, NVH engine techniques were advanced, and acoustic engineers spent vast amounts of time crafting and fine-tuning signature sounds for original equipment manufacturer (OEM) brands.

When quieter EVs hit the market, consumers were shocked, and acoustics specialists were concerned about the change in vehicle sounds, namely road noise and the more digitalized whirls and buzzes. Another concern was pedestrian safety since it was harder to hear EVs while walking down the street.

After nearly two decades, experts seem to have the EV soundscape more under control, creating a range of sounds for EVs, electric drivetrains and e-drives, including customized interior and exterior sound-scapes, enhanced silent driving experiences and pedestrian warning systems (PWS) or acoustic vehicle warning systems (AVAS).

Accounting for NVH

Every Emotors system needs to meet the specifications for e-drive sound and in-vehicle integration. Bonaventure Ndong Gumedzoe, NVH testing manager at Emotors, and his team in the NVH test lab help achieve this task.

Daouda Teuw, NVH engineer at Emotors, helps run the tests. This includes setting up each test run on their 72-channel Simcenter SCADAS™ hardware data acquisition unit. The lab-based setups include gluing and wiring accelerometers, installing specialized Simcenter Qsources™ hardware to the Emotors system, testing inside the anechoic chamber, monitoring the test runs and analyzing the noise or structural responses in Simcenter Testlab™ software and Simcenter Testlab Neo software.

Fatma Abid, NVH design engineer at Emotors, explains the process in more depth. “I work on modeling and simulating e-drive systems that guarantee the lowest acoustic noise by working closely with various technical teams, such as the electromagnetic engineers, the design team and the test team.

“I provide the test team with the initial simulation to optimize their test mesh, and then they provide me with test results so I can optimize my model to be more predictive. It’s important to have the most predictive models in the early stages of the project because we have to strike a balance between different noise sources, such as electromagnetic noise, and structural behavior.”

Using the optimized simulation from the NVH design team, Daouda Teuw targets specific areas on the Emotors system and uses classic NVH methods to identify structural resonances. Daouda Teuw then matches them with specific attributes, for example, magnetic force harmonics in the digital twin to predict the NVH behavior.

“To meet our customers’ NVH requirements, we perform classic experimental modal analysis in Simcenter Testlab,” says Bonaventure Ndong Gumedzoe. “We extract modal parameters, like frequency, modal shape and damping, and provide this information to the simulation team to confidently predict the NVH behavior of our Emotors products.

“Using the Simcenter testing solution easily takes us through the main tasks, step-by-step from the channel setup to final measurement analysis.”

Working and collaborating holistically

Like other industries, Emotors knows the importance of working outside of the NVH silo.

“We need to work with the electrical engineers, the control law engineers and the electromagnetic specialists to understand the sound sources of the electric drive and reach a compromise when it comes to an acceptable noise level,” says Bonaventure Ndong Gumedzoe.

By feeding accurate data into a digital twin, the company can make trade-offs early in the design process. Using Simcenter Testlab, the NVH team can confirm with color maps that the frequencies and harmonics are correct from the testing and digital twin sides.

“Our core challenge is to thoroughly test all aspects required to improve the NVH behavior of our product,” says Bonaventure Ndong Gumedzoe. “We work closely with the simulation team to find the right solution that matches NVH requirements and other areas like electromagnetics and electric drive control. Then, before we implement it, we put it back in the loop to test to see if it works as well under experimental conditions as it does in the simulation.”

Despite being a newer team, the NVH team strives to look at every angle to ensure their processes are functional and efficient. To help achieve this, Emotors leverages technical support from Siemens.

“We are very pleased with Siemens’ technical support,” says Daouda Teuw. “We often call them when we have some new measurement method to implement or when we start working with new equipment like the Simcenter Qsources for our next test campaign.

“Simcenter testing hardware is very user-friendly. We perform tests very quickly, even with all 72 channels.”

“Leveraging Simcenter SCADAS hardware has a very high sampling frequency from each channel,” says Bonaventure Ndong Gumedzoe. “The level of accuracy for our work is ideal. With Simcenter Testlab, each step is logical and easy to follow. It is great to have the geometry close to the channel setup. This way, Daouda Teuw can check that everything is going well and quickly fix any mistakes. We save a lot of time during preparations and test runs.”

Benefiting from Simcenter products

Thanks to Cédric Plasse’s experience, the Emotors team understood the importance of research and development (R&D) and advanced engineering for early product development. Due to this knowledge and Siemens solutions, Emotors created a series of next-generation e-drives in five years ranging from 25 to 250 kilowatts (kW) that are used in Stellantis brands like Peugeot, Opel, DS Automobile and Jeep. This was possible thanks to integrating the e-drive into the EV and manufacturing modularity.

“We need to have high volumes in our plant and not too much diversity, so we have two platforms covering our smaller and bigger motors, respectively,” says Cédric Plasse. “These two platforms can cover 25 to 250 kilowatts within the same production process. We develop standard products that can quickly adapt to our customers’ needs. We are very quick-to-market based on our continuous development process and platform manufacturing strategy.”

After using Simcenter testing solutions for modal analysis, the team discovered that Siemens had tools for studying psycho-acoustics to understand what the EV driver and passengers perceived while driving.

“A human being is not objective, like a measurement of harmonics that we can do in an anechoic room,” says Cédric Plasse. “The Siemens solution was the only tool we could use to successfully correlate the driver’s feelings with the measurements we took in the chamber. As engineers, we can only improve what we measure.

“We design many things digitally but can’t do everything with just our digital models. To be quick-to-market and accurate, we need to calibrate our models with test measurement data. Our NVH test engineers benchmarked all the tools on the market, and it appeared quite quickly that Siemens tools were the best.

“With our Siemens tools, in the case of acoustics we measure the noise and then we calibrate our model. Thanks to that, we can target the best trade-offs between noise, performance and cost for our customers.”

Another benefit is getting the rational and irrational human factors to match.

“We are performing in-vehicle testing because we currently have good results on our test benches, but for in-vehicle we have something different,” says Bonaventure Ndong Gumedzoe. “We have already discovered some good tools from Siemens, like the Simcenter SCADAS XS and the Simcenter SCADAS 3D binaural headset. It works with a tablet, and it is very small equipment that we can bring into the vehicle and perform the tests easily.”

The team is constantly looking for new ways to expand its commitment to NVH engineering excellence and finding exciting tools to add to their processes.

“When I speak with my NVH team, they say that the Siemens support is very professional and there is good communication,” says Cédric Plasse. “We are trying to use the Siemens tools across all domains. This is a good thing because we can capitalize on having more people on both sides – the simulation and the test sides – talking to each other. This is a good driver to improve communication. We will capitalize on the success between Siemens and Emotors as we introduce more motors to the market in the future.”