Modelling of an Electric Road System with Focus on the Inductive Power Transfer

Fabian Gumpert1, Michael Schmidt1, Jan Lohbreier1
1Technische Hochschule Nürnberg Georg Simon Ohm, Nuremberg, Bavaria, Germany
Published in 2023

The transport sector is one of the largest emitters of climate-effecting emissions. Thus, a major transformation in this sector is necessary to achieve Germanys and EUs ambitious goals of CO2 neutrality. In these transitions, fossil fuel-based engines will be replaced by sustainable technologies in which electric mobility plays an important role to reduce the CO2 footprint of the transport sector. However, electric vehicles have some disadvantages compared to competing technologies, especially for heavy goods transport (e.g. reduced range or long charging times). Electric road systems (ERS) are a promising approach to overcome these problems. The ERS can be separated into two sides, the primary side (integrated into the road) and the secondary side (integrated into the electric vehicle). The coil on the primary side transmits energy via induction to the secondary coil which can pick up the energy. This received energy can be used to charge the batteries while parking (static charging) or driving (dynamic charging). The primary coil provides a double-D layout which is particularly advantageous for dynamic charging process. Here, we present a digital twin of the primary side of the ERS in which different modelling techniques are combined. In a first step, an equivalent circuit is used to model the components of the primary side, with particular emphasis on the double-D coil. A 3D model of a coil and the surrounding air is simulated with the ACDC Module in COMSOL Multiphysics®. The transient current signal which is applied to the primary coil can be derived from this model. In the next step, the signal is transformed to the frequency domain using a Fourier transform (FT). The results from the FT are used as input for a Frequency Domain study in order to investigate the frequency dependent components of the magnetic field in COMSOL®. Next steps will be the implementation of the secondary part of the ERS. After rigorous experimental validation, the model will serve as digital twin of the ERS and will be able to predict the transmission efficiency under different conditions (for instance coil overlap or distance between the primary and secondary coil). The work is part of the joint project E|MPOWER, which is recently founded by the German Federal Ministry for Economic Affairs and Climate Action. The digital twin of the ERS complements a novel measurement setup which is also developed within E|MPOWER. A 1-km section of Autobahn in Northern Bavaria will be equipped with the ERS technology to demonstrate the approach.

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