Help needed for Fourier analysis of a triangular wave

In summary: However, I will need to compare my results with yours to be sure.In summary, the function in the original post is the correct one, but the intervals for t need to be rescaled.
  • #1
sabrank
3
0

Homework Statement



Fourie analysis for a boost converter
Where d = duty cycle, A = amplitude and t = time

Homework Equations




Fx = (2At/d) for 0<t<d/2, -A+(2A/(1-d))*(1-t-d/2) for d/2<t<(1-d/2); (2A/d)*(t-1) for 1-d/2 <t<1.
Where d = duty cycle, A = amplitude and t = time

The Attempt at a Solution



My solution is kind off large, I need need another solution to compare my ans with before writing a script to execute this function.
 
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  • #2
I recast your problem slightly and got a pretty compact answer. Instead of working with the interval [0,1], I used the interval [-π,π], took advantage of the fact it is an odd function, and got

[tex]f(x) = \sum_{n=1}^\infty \frac{2A\sin{n\pi d}}{d(1-d)n^2\pi^2}\sin nt[/tex]

Your d might be my 1-d and vice versa, and you can rescale t by a factor of 2π to get back to your original function.
 
  • #3
Thank you Vela, currently trying to model the equation in MATLAB or maple 13, hopefully I will. Cheers
 
  • #4
Please find attached the wave form I am trying to analyze. I was actually able to simulate the equation given by Vela but the output was symmetrical around zero while my original wave form as shown in the attachment was not symmetrical around zero.
I feel there should be a dc component in order to achieve this waveform consequently an odd function might not be assumed. Please note I have no proof of this.

A is the peak amplitude and 2A could be taken as peak to peak value (A-(-A)), which is equal to 3 in the attached waveform though I will prefer non usage of real value for 'A' because the value of 'A' changes with a change in other parameters e.g. d.

I will appreciate all assistance and suggestion. Thank you
 

Attachments

  • waveform.xls
    31 KB · Views: 182
Last edited:
  • #5
I'm assuming the function you gave in your original post is the correct one as the one expressed on the spreadsheet has apparent mistakes in the intervals for t.

I've attached a plot of your original function and the series I found (10 terms and with t appropriately rescaled). I used A=1 and d=1/4 for this particular plot. They look the same to me.
 

Attachments

  • fourier.jpg
    fourier.jpg
    7.2 KB · Views: 370

1. What is Fourier analysis?

Fourier analysis is a mathematical technique used to break down a complex signal into its individual frequency components. It is based on the concept that any periodic signal can be represented as a sum of simple sine and cosine waves with different frequencies, amplitudes, and phases.

2. How is Fourier analysis applied to a triangular wave?

To apply Fourier analysis to a triangular wave, the wave is decomposed into a series of sine waves with different frequencies and amplitudes. These sine waves are then summed together to recreate the original wave shape. The more sine waves that are included in the analysis, the more accurately the original wave can be reproduced.

3. What is the purpose of using Fourier analysis on a triangular wave?

The purpose of using Fourier analysis on a triangular wave is to better understand the frequency content of the wave and to be able to manipulate or filter specific frequency components. This can be useful in various applications such as signal processing and image compression.

4. What is the difference between a Fourier series and a Fourier transform?

A Fourier series is used to represent a periodic function as a sum of simple sine and cosine waves, while a Fourier transform is used to analyze a non-periodic function by decomposing it into a continuous spectrum of frequencies. In other words, a Fourier series is used for periodic signals, while a Fourier transform can be applied to both periodic and non-periodic signals.

5. Do I need any special software or tools to perform Fourier analysis on a triangular wave?

Yes, you will need a software or programming tool that has the capability to perform Fourier analysis. Some commonly used tools for this purpose include MATLAB, Python, and Mathematica. These tools have built-in functions or libraries for Fourier analysis that can be applied to a triangular wave or any other signal.

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