So, I've been able to work through all the values so far but seems like I have a problem with the summation notation since the THD of alpha does not converge to a solution:
ACCEPTED SOLUTION
Accepted Solutions
Not sure why, but the problem is "only" n=2 and function I.a
The function you integrate does not look malicious
Some additional observations:
EDIT:
Solution - Set the system variable TOL to a lower value. Either write TOL:=10^-8 at the top of the sheet in front of the function definitions or use the menu.
Doing so makes the integral converge
The plot below with variable values of alpha takes very long. I stopped it and used a larger step width to speed it up.
It looks like THD is independent from alpha
Not sure why, but the problem is "only" n=2 and function I.a
The function you integrate does not look malicious
Some additional observations:
EDIT:
Solution - Set the system variable TOL to a lower value. Either write TOL:=10^-8 at the top of the sheet in front of the function definitions or use the menu.
Doing so makes the integral converge
The plot below with variable values of alpha takes very long. I stopped it and used a larger step width to speed it up.
It looks like THD is independent from alpha
Its not that difficult to track down errors like this using "try..on error".
It was surprising that just the single value n=9 threw the error and all others worked fine.
The usual way would be to increase the value of CTOL and see if convergence could be achieved that way. Not sure why I had the idea to decrease TOL 😉
To calculate correctry, TOL is sensitive and integral from -L to L gives bug error at 80 to 100 degree.
Divide it from -L to 0 and from 0 to L makes good answer. Prime 9.
On(t,alpha) is unit step function to make rectifired signal(t) at angle alpha. It is pink plot below to make blue voltage signal.
FC(f,N,L) is a function in Mathcad help or tutorial of Fourier transform function. f is waveform, N is evaluated harmonics number and L is a half of fundamental period T.
Ofcourse if you using R only and not includes L or C, the shape of i(t) is as same as v(t). Then the Harmonic Distortion of AC current is as same as Voltage waveform. But to find the Total Harmonic Distortion of AC current, it must use Fourier Analysis. And it is very good question to calcilate RMS value of wave signals with using both
Could you tell me please where is it defined phi (t) (greek name)l signal that is used for calculating the signal On(t,alfa)?
Could you share please the definition of phi(t)?
Thank you.
The function
Numerics in Prime:
Numerics in Mathcad 11:
I think the symbolic processor in Mathcad 11 gives the best value:
Success!
Luc
