Research & Development at EMC Test NRW

Using dummy loads for engines

Engine loads are difficult to execute inside anechoic chambers for EMC tests on drive inverters. Instead we use a passive dummy load (developed by EMC Test NRW) which serves to imitate electrical impedance of three-phase motors. This enables us to install measuring equipment quickly inside anechoic chambers or shielded rooms, thus increasing efficiency.  

_{Image 1: left, equivalent motor load during magnetic field measurement; right, comparison of a CISPR 25 interference voltage measurement between motor and dummy load}

In order to measure high-voltage components, you first need DC voltage supply. Then you interconnect a battery dummy load between the high-voltage component and the voltage supply to adapt its electrical impedance to that of a regular lithium-ion battery. This facilitates proper emissions tests leading to an increase in safety when the components are later integrated.

Compliance assessments usually rely on steady operating states. But in emissions tests, we regularly see that the operating state affects the result significantly. Special control software enables us to measure the effect of dynamic states on the emissions of inverters.

We use shielded HV cables and appropriate connectors to decouple 12V and high-voltage vehicle systems. Via the twin-lead cable procedure, we can evaluate their shielding effectiveness. The benefit here is that we not only measure their shielding effectiveness but can also detect potential weaknesses in the test specimen. EMC Test NRW offers flexible adjustments for various connectors, thus enabling comprehensive EMC compliance for these components.

• ​Project partners: RWTH Aachen, Hochschule Ruhr West, Voltavision GmbH, Embex GmbH
• Project executing agency: TÜV Rheinland Forschungsmanagement GmbH (PT-TÜV), Federal Ministry for Economic Affairs and Climate Protection (BMWK)
• Project duration: 2023 to 2025
   

Subproject: EMC of electric drive systems with novel resonant converter topology, focus on development of a motor load and measurements

The electrification of the powertrain continues to progress, which brings new power-electronic controlled drive systems into existing vehicle architectures. With regard to EMC, drive converters in particular are sources of interference that can negatively influence other functions of the vehicle. A common approach is to reduce this influence through extensive filtering and shielding measures.

In this context, the joint project pursues a completely different approach. To reduce interference emissions, an inverter based on the resonant converter topology is to be developed and tested as part of a demonstrator. In such a resonant converter, the phase voltage is not switched to the motor as usual via a pulse width modulation (PWM) but directly with the rotating field frequency. In this operating mode, an additional variable capacitance ensures that the motor is in resonance at the excitation rotating field frequency.

For EMC Test NRW GmbH, the main focus is on the investigation of the electromagnetic emissions of this drive system based on resonant converters. For this purpose, a motor load with reduced self-emission must be used, especially on the motor side, so that on the one hand the operating behavior of new inverter and on the other hand the EMC properties can be investigated. Such a low disturbance rotating load will be realized by EMC Test NRW GmbH as part of the project.

Subproject: EMC inductive energy transmission, focus on measurements and study

• Project partners: Institut f. Automation und Kommunikation e.V. Magdeburg, Delta Energy Systems (Germany) GmbH, EMC Test NRW GmbH, MAHLE International GmbH, Wiferion GmbH

• Project management agency: Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR, German Aerospace Center), Bundesministerium für Wirtschaft und Energie (BMWI, Federal Ministry for Economic Affairs and Energy)

• Project duration: 2021 to 2024

The inductive energy transmission enables the automatic, wireless charging of electric vehicles during every parking process or dynamically while driving. This makes this technology a key to autonomous driving and grid-stabilizing charging. A successful dissemination requires a complete standardisation.

The main goals of the joint project EMPOWERED are therefore the development of a positioning aid that can be reached by consensus worldwide and a uniform, standardized EMC measurement method in order to support the international standardization work on inductive energy transmission for electric vehicles at IEC, ISO, SAE and ETSI. Structured measurement series are intended to systematically reduce interference potentials of inductive energy transmission systems, e.g. compared to radios and AM radios and thus realistic EMC limit values for a far-reaching coexistence are justified.

EMC Test NRW GmbH has the main focus on the metrological investigation of the electromagneticemissions of WPTsystems (Wireless Power Transfer) in the field of technical EMC as well as in connection with amateur radio and AM radio receivers. In order to standardize both, the measurement environment and the measurement method, we pay particular attention to the required test setup.

_{Fig. 7: Test-Setup}

• Project partners: Robert Bosch Car Multimedia GmbH, Infineon Technologies AG, Zuken GmbH, Microchip Technology Germany II GmbH & Co. KG, CONTUNITY GmbH, Luminovo GmbH, HOOD GmbH, CLOUD & HEAT Technologies GmbH, Binder-Elektronik GmbH, DIQA Projektmanagement GmbH, InnoZent OWL e.V., Fraunhofer-Institut für angewandte Informationstechnik (FIT), Forschungszentrum Informatik (FZI), Technische Universität Dortmund, Helmut-Schmidt Universität, Technische Universität Berlin, Hochschule Hamm-Lippstadt, EMC Test NRW GmbH, Dortmund
• Project managment agency: TÜV Rheinland andBundesministerium für Wirtschaft und Energie (BMWI, Federal Ministry for Economic Affairs and Energy)
• Project duration: 2021 to 2024

How can artificial intelligence support the development of electronics for future vehicle generations? EMC Test NRW is one of eighteen partners in the "progressiveKI" research team who want to develop a generalized AI-powered design process for automotive electronic systems. As part of the project, EMC Test NRW will take a close look at electromagnetic compatibility in the design of new vehicle electronics. For example, it will be explored which parameters and information are used to achieve machine learning. Through machine learning, electronic systems are to be developed faster, more reliably and more cost-effectively. The aim is to achieve a significant acceleration of innovation.

_{Fig. 6: progresivKI}

• Project partners: Aptiv, TU Dortmund University, University of Wuppertal, IQZ

• Project managment agency: EFRE.NRW

• Project duration: 2018 until 2022

Our project AFFiancE is currently looking into automated features affected by environmental conditions. Against this backdrop, our project partner Aptiv is developing a central controller and a testing platform that enable the assessment of different features in driverless vehicles. EMC Test NRW is examining the effect of electromagnetic disturbances on sensor systems and communication within the autonomous vehicle. Due to extensive environmental sensors, the data traffic in these vehicles is significant, but—thanks to 2-wire Ethernet communication—manageable. EMC Test NRW checks how susceptible to interferences these communication systems actually are and identifies potential weak spots. They furthermore examine the effect of these disturbances on actual automated driving datasets in order to emulate these effects on Aptiv’s testing platform.

_{Fig. 4: above, data rate on disturbance pulse;
below, test set-up with interference injection via capacitive coupling clamp}

• Project partner: NXP, TU Dortmund University, Robert Bosch GmbH, SiL, RWTH Aachen University, AiX Control

• Project managment agency: VDI/VDE/IT and BMBF (Federal Ministry of Education and Research)

• Project duration: 2018 until 2021 (possible extension to 2022)

The project RobKom explores the EMC of autonomous vehicles. Increased interference potential in the driver system components and strict requirements regarding immunity for the communication systems in automated driving features pose challenges for EMC. The project is, thus, looking into the question of how to reduce unwanted emissions by using specific input procedures on optimised power electronics. It also monitors the coupling between communication and high-voltage vehicle systems to identify potential areas of improvement and increase interference immunity. EMC Test NRW measures emissions from the source of interference and analyses the immunity of the communication and the system coupling. In cooperation with the project consortium, a demonstrator model with optimised EMC features will be built and tested in the lab at the end of this project.

_{Fig. 5: above, overcoupling of disturbances in HV systems on parallel wires; below, model demonstrator}

• Project partner: University of Wuppertal

• Project sponsor: Central Innovation Programme for small and medium-sized enterprises (ZIM)

• Project duration: 2017 until 2020

During the course of this project, EMC Test develops and analyses EMC testing methods for inductive charging systems for electric vehicles.  We focused on developing test peripherals that can measure charging stations and vehicles individually. Concerning EMC compliance for inductive charging systems, emissions are a contentious matter. We designed a replica of a car body and a filtered charging station specifically for charging station and vehicle assessments (see fig. 2).

_{Fig. 11: on the left, assembling magnetic field measurement; on the right, effect of filter in inductive charging stations}

• Project partner: Scienlab GmbH, University of Duisburg-Essen

• Project sponsor: Central Innovation Programme for small and medium-sized enterprises (ZIM)

• Project duration: 01 September 2014 until 31 March 2017

During the course of this project, the consortium developed a test environment that—for the first time ever—enabled comprehensive tests on charging stations and vehicles. This environment emulates the missing counterpart when it comes to power as well as communication. It is available in the EMC Test NRW lab and generates an output of up to 150 kW (click here for further information on test environments for charging stations).

_{Fig. 8: on the left, test set-up electric vehicle; on the right test set-up charging station}

• Project partner: TU Dortmund University, TÜV Informationstechnik GmbH, ASL Services

• Project sponsor: Progres.nrw

• Project duration: 04 July 2013 until 30 September 2015

_{Fig. 9: set-up for conducted emissions tests}

• Project partner: TU Dortmund University, TÜV Informationstechnik GmbH, ASL Services

• Project sponsor: Progres.nrw

• Project duration: 17 May 2011 until 31 July 2015

_{Fig. 10: set-up for screening attenuation}