High efficient inductive energy and data transmission system with special coil geometry

This paper presents a combined contactless energy and data transmission system, which is able to detect and to identify a secondary device and which is also able to check its absolute position during the energy transfer. Such an identification is needed in many fields of application under aspects like safety and security. Compared to conventional industrial communication systems like Bluetooth or W-LAN using the near field technique allows the elimination of interferences between systems which operate at the same transmission frequency and furthermore which operate in a very near range side by side. This reduces the complexity, the costs and the installation effort of the overall system and makes a transport protocol for the data transfer completely unnecessary. In this paper a combined inductive energy and data transmission system is proposed which allows a power transmission of 1 kW over an air gap of 30 mm as well as an inductive data transmission on the principle of inductive near field coupling at the same time. By using a special coil geometry for the data transmission, a nearly full separation between the inductive energy and data transmission channels is reached. For dimensioning the coil parameters the 3D-FEA and analytic calculations of the electrical behaviour are used. The interferences between the energy and data transmission system are modelled and simulated with a multi coupled transformer model. The paper shows important aspects of the optimisation process of the data coils and also presents an optimal coil configuration in PCB layout. Finally the simulation and the measurement results are discussed in the paper.