Nonlinear magnetic field analysis for 3D electromagnetic contactors

A new approach considering the nonlinearity of the electric core is proposed to analyze the magnetic field and magnetic force of 3D electromagnetic contactors. The nonlinear constitutive law is established by measuring the B-H curve of the core experimentally. Finite element method is used to model the electromagnetic responses of the system, in which the 3D Ampere's circuital law is implemented in PDE weak form. In order to analyze the nonlinear responses of the magnetic field and magnetic force, the measured constitutive law is incorporated with the weak form equation by numerical interpolation. Both the static and transient responses of the electromagnetic system are studied by solving the coupled weak form equations step by step. Experimental results show that the proposed model has good predictions of the magnetic force. The saturation due to the nonlinearity of the B-H curve can be described as well. This modeling framework offers an advantage to solve the nonlinear responses of 3D electromagnetic systems without theoretical modeling the complex constitutive law of the electric core.