Design-oriented analytical study of a linear electromagnetic actuator by means of a reluctance network

This paper presents an analytical electromagnetic model of a rectilinear actuator. The model is based on a reluctance network, which can be solved with the same techniques as for an electric circuit. The analytical model was originally built to be used with an algorithm of geometric optimization for design purposes. The authors first show the way in which leakage flux are taken into account. They then describe the innovative method they have developed for the reluctance evaluation of different parts of the actuator. The method considers magnetic saturation and flux routes in remarkable cylindrical geometries. The authors also describe an equivalent model of the air gap, which gives the values of force applied on the moving part and the corresponding reluctance value of the air gap. An evaluation of the model accuracy by comparison with a numeric determination (finite elements) makes it possible to carry out further optimizations of the rectilinear actuator. Finally, the authors interpret the model deviations, and they suggest corresponding improvements of the analytical model.