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carrierwavesimulinkpwm

Creating positive and negative values from PWM


I have the following simple system:

enter image description here

Where my triangle carrier is: (0,0) (0.0004,1) (0.0008,0).

The sine wave is: Amplitude 0.5, Freq 10(rad/sec) and Phase 10 rad

Then, I create a PWM inserting it into 2 transfer function and I obtain the following result:

enter image description here

It is easy to see that by giving the blue pulses (generated by comparing the carrier and the sine wave), the output of the system (red line), manage to follow the original input (black line). However, it happens only when the original input was positive.

How can I modify the system in such a way that it will follow the input at the negative values as well?

Thank you.


Solution

  • Mathematically you can do the following, although whether that's the right thing to do in terms of your PWM I can't be sure.

    Simulink Model