Analog circuits in Simulink

I want to implement simple circuits such as RC circuits in simulink with input from a signal generator. Unfortunately, I always encounter errors such as "no solver block" etc. Here's the pic of the model: http://img713.imageshack.us/img713/5582/96748583.png

I am new to Simulink, so this might seem a bit silly but any help is welcome.

Answer 1

[Doug Eastman]

The error seems to indicate that you are missing a solver block, but you have one in the image you've attached. For the case of the attached image, I would expect a "missing reference node" error. You need to include at least one Electrical Reference in a Simscape electric system.

Also I noticed you are trying to connect a regular Simulink Scope to your circuit. To measure a value in the circuit you need to use an Electrical Sensor such as a Current Sensor or Voltage Sensor and then convert that signal to a regular signal using a PS-Simulink Converter block, then you can send that signal to a Scope.

It might be easiest to start from an example. Try loading ssc_new_elec by typing that at the MATLAB command prompt. That brings up a basic model and a helpful palette that you can use to quickly build up more models.

[bijeta Chakraborty]

Hello Doug,

I am working on implementation of PWM generator circuit which uses a carrier signal and input signal. I am trying to use a comparator for that.But when I start simulating it gives me error of solver.

I used the ssc_new_elec to start with and it gives me error as below

Nonlinear solver: Linear Algebra error. Failed to solve using iteration matrix.

Initial conditions solve failed to converge.

Equations of one or more components may be dependent or inconsistent. This can cause problems in transient initialization. Here is the set of components involved:

'comparator/Voltage Source (SL)/Controlled Voltage Source'

Any help/comments would be helpful.

Best Regards

Bijeta Chakraborty

Answer 2

[bijeta Chakraborty]

Hello Doug,

I am working on implementation of PWM generator circuit which uses a carrier signal and input signal. I am trying to use a comparator for that.But when I start simulating it gives me error of solver.

I used the ssc_new_elec to start with and it gives me error as below Nonlinear solver: Linear Algebra error. Failed to solve using iteration matrix. Initial conditions solve failed to converge. Equations of one or more components may be dependent or inconsistent. This can cause problems in transient initialization. Here is the set of components involved: 'comparator/Voltage Source (SL)/Controlled Voltage Source'

Any help/comments would be helpful.

Best Regards Bijeta Chakraborty

[Sanjay]

Please specify the inputs to the comparator i.e. what kind of input pulse are you using and the carrier pulse being given.

Try using a Schmitt trigger in your circuit instead of a plain comparator. Mind you, the Schmitt trigger is not a library model in Simulink and hence you would have to make one for yourself. While doing so, use the finite gain op-amp with matched resistances.

The Schmitt trigger helps you set the threshold at input and is also fast enough. Anyhow, I would suggest that you look at digital models for your PWM as these analog modules cannot be used on an FPGA, if that is your final goal.