MODEL OF THE ELECTROMAGNETIC LINEAR ACTUATOR FOR OPTIMIZATION PURPOSES

The goal is to present a more accurate model for optimization of design and of a supply control. The object is an electromagnetic linear actuator which is built of series of coils and of a ferromagnetic moving core. The coils are supplied by time series of current impulses. Even though that linear electromagnetic actuators are commonly known their applications are not wide. This is mainly because of the low energy efficiency. The efficiency is here understood as a ratio of the kinetic energy of the core at the outlet of the device to the electric supply energy delivered to the coil. The efficiency can be improved by design parameters optimization and by the accurate supply control, as well, but an adequate accuracy of the mathematical model is required for optimization process. In this paper a simulation model is presented, with a careful consideration of the hysteresis of ferromagnetic parts, of nonlinear distribution of the magnetic field and of the dimensions of all coils. The time-dependent non-uniformly distributed magnetic field is analyzed by the FEM method. The computer simulation results and experimental data of magnetic flux density are compared. Special sensors of the Colossal Magneto-Resistance (CMR) effect have been used for verification of the simulation results (Balevicius et al. 2005, Schneider et al. 2007). The Multi-Attribute optimization has been completed and the Pareto set is defined, by evolutionary optimization methods.