Simulink Control Design™ - MathWorks

Specifying Custom Linearizations for Simulink Blocks

This example shows how to specify the linearization of a Simulink block or subsystem.

Introduction

The command LINEARIZE in Simulink Control Design gives a linear approximation of a

Simulink model using an exact linearization approach. This linearization is valid in a small

region around a given operating point. This approach works well for most Simulink

models, but in some cases you need to modify the exact linearization approach to take

into account the effects of discontinuities or approximate the dynamics of derivative or

delay action. Many built-in Simulink blocks, such as saturation or the dead zone non-

linearities, provide the ability to select "Treat as gain when linearizing" to control this

behavior. In this example you specify a custom linearization for a subsystem to

approximate the linearization of a PWM signal.

Linearizing a Model with a PWM Generation Subsystem

The following example model has a subsystem scdpwm/Voltage to PWM, which models

a PWM signal that enters a plant model.

mdl = 'scdpwm';

open_system(mdl);

When you linearize this model using the standard configuration, the resulting linear

model has a gain of zero.

io = getlinio(mdl);

sys = linearize(mdl,io)

sys =

D =

Step

Specifying Custom Linearizations for Simulink Blocks.... 2-