Abstract
KEYWORDS – linear eddy current brake, frictionless and wear-free braking, electromagnetic compatibility (EMC), finite element method (FEM), adaptive mesh refinement
ABSTRACT - Due to growing globalisation, efficient passenger transport becomes increasingly important. Eddy current brakes (ECB) will make a decisive contribution in achieving this task, as already demonstrated successfully on ICE3 (1) trains. Providing additional braking forces which are totally independent of any adhesion, the problem of limited force transmission between wheel and rail can be solved as well as the thermal limitation of classical friction brakes. Thus, the cruising speed can be increased and larger track gradients can be handled. Furthermore, the cost intensive wear of friction materials can be reduced significantly.
Despite these advantages, eddy current brakes have not been widely adopted, mainly because of concerns regarding the electromagnetic compatibility (EMC) between the brake and trackside sensors (3). In order to ensure EMC for the latest generation of ECBs and sensors, time and cost intensive laboratory and driving test had to be performed. To reduce the effort of approval for the next generations, an electromagnetic model of the ECB has been developed, allowing computer-aided investigations of EMC already during the design process. Deriving worst case scenarios from this model, a standard can be defined to ensure EMC over the entire operation range for next generations of eddy current brakes and trackside sensors.
The paper presents this electromagnetic model which has been developed in the ECUC (Eddy CUrrent brake Compatibility) project (4), co-funded by the European Commission under FP7 Transport. After applying an innovative mapping method to this 3D finite element model to reduce the computing effort, the simulation results are verified by test bench trials. Concluding, an intensive parameter study is performed to identify the worst case conditions for entire operation range of ECB. Based on this dataset, a standard to ensure EMC will be defined.