An integration algorithm for simulating stiff electrical networks

There have been developed an effective explicit variable-order and variable-step numerical method DISPF with improved regions of stability and with accuracy and stability control for simulating stiff systems at Institute of Computational Modelling of the Siberian Branch of the Russian Academy of Sciences. However, using this method is limited to not highly stiff problems. The algorithm's effectiveness can be increased by controlling the stiffness of the problem and choosing numerical scheme according to the behavior of the solution. The computational costs for solving a problem can be decreased by confining the time during which an implicit method is used. The paper considers an adaptive algorithm DISPF1_RADAU based on the original method DISPF and the well-known implicit method RADAU5. The algorithm is given. In order to test its efficiency, the Van der Pol oscillator is used. The algorithm's advantages over using the methods independently are shown. The new algorithm is used to simulate a ring modulator.