SimPowerSystems

Limitations of the Nonlinear Models

Because nonlinear models are simulated as current sources, they cannot be connected in series with inductors and their terminals cannot be left open.

If you feed a machine through an inductive source, power2sys prompts you with an error message. You can avoid this by connecting large resistances in parallel with the source inductances or across the machine terminals.

A series RC snubber circuit is included in the model of the Breaker block and power electronic blocks. You will not have any problem if you keep these snubber circuits in service. The snubber can be changed to a single resistance by setting Cs to Inf, or to a single capacitor by setting Rs = 0. To eliminate the snubber, specify Rs = Inf or Cs = 0.

Modifying the Nonlinear Models of the powerlib_models Library

To use your own powerlib_models library, you must first copy the powerlib_models.mdl file into your working directory or any other directory. If you are using a directory different from the current directory, you must specify this new directory in the MATLAB search path in front of the standard blockset directory.

Then you can customize this new powerlib_models library as long as you do not change the names of the blocks, the number of inputs and outputs, and the number of parameters in their dialog boxes. The next time that you run the simulation, the modifications will take place in your circuit.

The Discrete Library

Creating Your Own Library of Models