Time-domain partial element equivalent circuit solver including non-linear magnetic materials

This paper presents a novel partial element equivalent circuit formulation to handle 3-D non-linear problems. Since the displacement currents are taken into account, the proposed formulation is not restricted to low-frequency applications, although the propagation delays are neglected. The non-linear problem is solved by means of the Newton-Raphson algorithm. Special care is taken in order to analytically compute the Jacobian of the problem. Furthermore, an adaptive setting of the time step is adopted in the transient analysis allowing to maintain the size of the time step as large as possible while preserving the accuracy. Computed results for a closed magnetic circuit and the testing electromagnetic analysis methods workshop problem 10 are reported.