Rapid computer-aided design method for fast-acting solenoid actuators

This paper describes a general method for preliminary design of fast-acting solenoid actuators. Moving armature, drive circuit, and nonlinearities are modeled, as well as eddy currents for solid iron devices. The electromagnetic model is obtained by computing two magnetization characteristics corresponding to the extreme positions of the armature and a novel interpolation function for the intermediate positions. This function, characterizing the magnetic configuration of the actuator, is computed analytically and leads also to an analytical formulation of the magnetic force. In order to achieve extremely fast computation, eddy currents are modeled through a new type of electric equivalent network, derived directly from Maxwell´s equations and taking into account the actual BH nonlinearities, moving armature, and device geometry. The method is demonstrated on a pot-core solenoid actuator and compares favorably with finite-element results and measurements