Ideal switches

In PLECS, the models of power electronic components, circuit breakers etc. are based on ideal switches. In the closed position they represent a true short-circuit (Ron = 0) and in the open position an ideal open circuit (Roff = inf). They switch instantaneously between these two states. The use of ideal switches in modeling offers three major advantages: ease of use, robustness and speed.

Simple to use

An ideal switch does not have any parameters such as on-resistance or snubber capacity to worry about. Often, you do not even know these values, especially in system simulations where parasitic effects are of little interest. If, however, you want to model a specific power electronic device in more detail you are free to add such components as a forward voltage or an inductance according to your needs.

Robust

The use of snubber circuits in other simulation programs greatly increases the complexity and stiffness of the simulation model. Such models usually require a fixed time-step simulation or a stiff solver. The fact that PLECS can do without snubbers gives you freedom to choose between all variable time-step solvers offered by Simulink, including the robust and accurate ode45.

Fast

In conventional circuit simulation programs, switching transients are computationally expensive. The finite slopes force the program to take small time steps. In PLECS, this problem is avoided by the instantaneous operation of the ideal switches. Only two steps are needed for each switching event. This speeds up the simulation considerably.

Behavioral models

In addition to the ideal switch models, PLECS offers behavioral models for the simulation of dynamic parasitic effects in power semiconductors, such as diode reverse recovery or limited di/dt during IGBT turn-on and turn-off. These models are intended to detect critical overvoltages that may occur across stray inductors.