A method for fast time-domain simulation of networks with switches

A method for fast time-domain simulation of piecewise-linear networks with switches is described in this paper. The method is based on a discrete-time switch model that consists of a constant conductance in parallel with a current source. In each simulation step, the value of the current source is updated as a function of known network signals. The function takes one of two forms, depending on the state (on or off) of the switch. Since the system matrix is constant, regardless of the states of the switches, simulation time is essentially the same as for a linear, time-invariant network of the same complexity. The paper discusses selection of the model and simulation parameters. The simulation algorithm is described and an example is included. It is shown that the method is not only efficient but also quite general and void of convergence problems. Its primary application is for long-term transient simulation of power electronic systems such as switching power converters.