3-D transient eddy-current simulations using FI/sup 2/TD schemes with variable time-step selection

A variable step size time integration method is used for transient eddy-current problems within the framework of finite integration implicit time-domain (FI/sup 2/TD) formulations. The time-step selection is based on embedded Runge-Kutta methods, which provide an error with the difference of the two solutions of different order. This error allows a prediction of the next time step, for which different types of controller strategies are compared. The accuracy and efficiency of the method is investigated with various numerical examples.