Simulink Control Design™ - MathWorks

This time delay accounts for the duty cycle frequency of the PWM signal which is at 100

Hz. To specify the delay on the subsystem scdpwm/Voltage to PWM right click on the

block and select Linear Analysis->Specify Linearization. The following block dialog in

which you specify the delay dynamics opens.

The following code is equivalent to entering the delay into the specification dialog.

set_param(pwmblk,'SCDEnableBlockLinearizationSpecification','on');

rep = struct('Specification','ss(1,''OutputDelay'',1/100)',...

'Type','Expression',...

'ParameterNames','',...

'ParameterValues','');

set_param(pwmblk,'SCDBlockLinearizationSpecification',rep);

Linearizing the model with the specified subsystem linearization now gives the expected

result.

opt = linearizeOptions('SampleTime',0);

sys = zpk(linearize(mdl,io,opt))

sys =

From input "Step" to output "Plant Model":

1

exp(-0.01*s) * -------------

(s^2 + s + 1)

Continuous-time zero/pole/gain model.

Comparing the Linearization and Simulation

You can compare the linearization of the model to the actual linearization using a

frest.createStep signal. It is important to note that the specification of the

2 Linearization