MTRAC: Computer program for transient analysis of circuits including magnetic cores

A square-loop magnetic core model,\dot{\phi} = \dot{\phi}_{elastic}(F,\dot{F}) + \dot{\phi}_{inelastic} (F,\phi), has been incorporated into the automated circuit-analysis computer-program TRAC. The modified program, named MTRAC, includes supplementary provisions for successive modes of operation, nonlinear resistor and inductor models, normal and circuit-failure run termination, monitor printout for debugging, etc. Based on linearization of nonlinear circuit elements and Kirchoff's current law, the computation involves an iterative solution ofV] = T]/[H], whereV] is the nodal-voltage matrix andT] and [H] are known current and conductance matrices of the circuit. Expressions are derived for the contributions to the [H] andT] matrices of various linear and nonlinear circuit elements, including magnetic cores. The input core parameters are based on either\phi(F)orB(H)data. The organization of MTRAC and that of a circuit-element subroutine are outlined. Time variables (voltages, currents, MMFs, fluxes, etc.) of complex magnetic-core circuits (up to 60 nodes) are computed and plotted automatically. All that the user has to supply is the general run-control specifications, the circuit topology, and the values of the circuit-element parameters. An example is given for a core-diode shift register.