Inductive Charging

Not only the increase of electric driving range, but also the improvement of user comfort is a crucial point for the success of battery electric and hybrid electric vehicles. In view of ergonomic and practical aspects of the charging process, wireless charging is a consecutive step for the development of charging infrastructure. We developed an inductive charging system for battery electric vehicles in order to facilitate an autonomous charging process without any user interaction. This approach leads to a tremendous improvement of user comfort and facilitates the necessary technology for an ubiquitary charging concept.

Project Targets

Design of a position tolerant wireless charging system

Transmission power of 3,7 kW (scalable up to 11 kW)

Charging without user intervention (“autonomous” electric driving)

Wireless communication between primary and secondary side


Selection of a suitable coil geometry and arrangement

Optimization of the coupling coils to reduce the system losses

Safe and efficient operation of the charging system


extremely compact vehicle side coils (diameter of a CD)

94% system efficiency up to the battery

Integration of a low-rate and robust information transmission channel (max.3,5 kW)

Project Partners

Fraunhofer Institute for Integrated Systems and Device Technology IISB

Research project in cooperation with the Chair of Electron Devices (LEB) and further chairs of the University of Erlangen-Nürnberg 


        Inductive Charging System








Ditze, S., Heckel, T., März, M., Influence of the junction capacitance of the secondary rectifier diodes on output characteristics in multi-resonant converters, 2016 IEEE Applied Power Electronics Conference and Exposition (APEC), Long Beach, CA, USA 2016

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Joffe, C., Roßkopf, A., Ehrlich, S., Dobmeier, C., März, M., Design and optimization of a multi-coil system for inductive charging with small air gap, 2016 IEEE Applied Power Electronics Conference and Exposition (APEC), Long Beach, CA, USA 2016

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B. Sanftl; C. Joffe; M. Trautmann; R. Weigel; A. Koelpin,

Reliabe data link for power transfer control in an inductive charging system for electric vehicles, 2016 IEEE MTT-S International Conference on Microwaves for Intelligent Mobility (ICMIM)



A. Roßkopf; E. Bär; C. Joffe; C. Bonse, Calculation of Power Losses in Litz Wire Systems by Coupling FEM and PEEC Method, IEEE Transactions on Power Electronics



A. Roßkopf; S. Schuster; A. Endruschat; E. Bär, Influence of varying bundle structures on power electronic systems simulated by a coupled approach of FEM and PEEC, IEEE Conference on Electromagnetic Field Computation (CEFC)



C. Joffe, Modular Charging Solutions, ECPE Workshop "Power Electronics for e-Mobility", 22 - 23 June 2016



Ditze, S.: Steady-State Analysis of the Bidirectional CLLLC Resonant Converter in Time Domain, INTELEC, Vancouver 2014



Joffe, C.; Ditze, S., Rosskopf, A.: A Novel Positioning Tolerant Inductive Power Transfer System,ETEV, Nürnberg, 2013

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