Design of a linear electromagnetic actuator for secondary suspension in a railway vehicle considering electromagnetic-thermal coupled field analysis under geometrical constraints

There is a growing demand for a reduction in lateral vibration in railway vehicles, which has an effect on ride comfort. For this purpose, active suspension rather than conventional passive suspension is suitable. A tubular electromagnetic (EM) actuator is appropriate for an active suspension as it has a high thrust density and controllability. Among the several driving methods of the actuator, a permanent moving-magnet type with slots that have easy wiring, and a high thrust density, was selected. To obtain the thrust force for a given actuator size, an EM-thermal analysis model was constructed and the maximum thrust was obtained. A model of 300 mm diameter and 600 mm length satisfied the target thrust of 7500 N. It is confirmed that the size can be further reduced when forced convection due to the operation of the train is applied.