Ultra-high power density e-Machine validation for Rimac Technology

Test programme to sign off the RT advanced new ultra-high power density hypercar e-Machine

Hypercar and EV technology company Rimac (pronounced ‘Rim-ats’) wanted to sign off its advanced new ultra-high power density e-motor. Therefore, they were looking for a suitable external partner. Drive System Design (DSD) was able to work as an extension of RT’s engineering team to utilise DSD’s latest high-performance e-motor test rig at DSD’s facility in the UK and carry out an agreed test program to validate the new product. In addition, DSD provided the e-motor’s engineering sign-off and captured extensive test data for use by Rimac’s engineers.Rimac e-motor

Destined initially for a specific customer application, the 3-phase IPM motor is one of the many products proposed in the Rimac Technology portfolio developed for their OEM client base. DSD fully characterised the performance and efficiency of the motor to validate earlier simulation carried out by RT, including automotive standard tests for peak and continuous power output and mapping of MTPA (max torque per amp) and MTPV (max torque per volt).

Durability testing was carried out 24/7 for four weeks, using cycles accurately constructed from data collected during simulated high-speed laps of the Test Cell 6Nürburgring track, frequently used for supercar development and evaluation. DSD’s motor testing was thus effectively HIL (hardware in the loop) testing, with the test rig operating in a highly transient ‘path following’ mode.

The entire program, including rig development and the test activities, took just twelve weeks, and DSD is confident this can be shortened for subsequent projects. The test rig can accommodate motors up to 450 Nm torque and 350 kW power output, running at up to 25,000 rpm. The test rig can also be configured to test motors up to 1,000 Nm up to 9,000 rpm. The complete cell includes a gearbox, drive motor, battery emulator, coolant conditioning systems, HBM power analysis, HBM precision torque sensors, NI data acquisition and rig automation system.

The Inverter calibration is demanding and complex. It requires a very accurate setup for a motor that is delivering supercar levels of performance. It would normally take several months of fine-tuning to ensure the inverter accurately controls a motor over very dynamic drive cycles and during incredibly precise efficiency mapping. Still, DSD only had a couple of weeks.

DSD writes its inverter and rig control system software to tailor advanced features to the customers’ needs. For this application, software was implemented that allowed rapid, fully automated mapping of the inverter calibration and implementing a torque control structure capable of safely ‘driving’ the Nurburgring for hundreds of laps.

RT’s global reputation as a leader in high-performance EV systems is founded on the highest technical standards, making it an acutely demanding customer. DSD was delighted to be accepted as an engineering partner, contributing its test and development know-how to complement RTc’s testing facilities and departments. In addition, the program exemplifies DSD’s ‘Under one roof’ capability, which integrates electrical, mechanical, software, control and analytical skills within the same facility.

“Rimac Technology is focused on designing, engineering, testing and manufacturing state-of-the-art technology for our OEM clients. As a fast-developing company with a demanding high-performance EV projects pipeline, we often face testing facilities capacity. Therefore, it’s important to us to find external partners with the necessary testing capacity to meet the rigorous testing standards we expect,”said Miroslav Macan, Chief Powertrain & Power Electronics Engineer at Rimac Technology.“DSD provided really close and effective collaboration with our in-house team, working seamlessly as an extension of our testing facilities to deliver a wide range of verification and validation testing services.”

Nevera Rimac Car

About Rimac:

Rimac Automobili and Rimac Technology designs, engineers, and manufactures electric hypercars and high-performance EV components for the global automotive industry. Founded in 2009 and headquartered in Zagreb, Croatia, it currently employs 1200 staff across four sites, creating core EV systems, from power-dense drivetrain systems to highly advanced autonomous driving infotainment technologies.

Major Rimac shareholders include Porsche and Hyundai Motor Group, and the company has also recently announced that it is the major shareholder of Bugatti in a joint venture with Porsche. Operating at the leading edge of EV technology, Rimac has always created its core product technologies by growing internal talent and developing the key competencies in-house. In addition to the design and manufacture of its hypercars, such as the Concept One and Nevera, Rimac Technology develops and supplies components to Aston Martin, Cupra, Renault, Automobili Pininfarina, Koenigsegg and others.

To learn more about the project, get in contact today with our team at DSD.