Dear All,
In my PV inverter, I have to analyze the AC filter capacitor qualitatively. The switching frequency is 4000Hz. To analyze the AC filter capacitor qualitatively, capacitor voltage and current value at various harmonics have to be checked with respect to fundamental value. Therefore, I would like to make a table for the same indicating f [Hz] v/s Uh/Un [pu] and f [Hz] v/s Ih/In [pu]
May I know from experts what all frequency are important to see the pu value?
I suppose 0Hz, 50 Hz (fundamental), 150 Hz, 4000 Hz (with side bands) are the most important. Can anyone suggest if I misses anything ?
Regards
Aalok
The following article can help u
http://dranetz.com/wp-content/uploads/2014/02/harmonics-understanding-thefacts.pdf
Hi Aalok,
I assume that by switching frequency you imply the carrier frequency. And 50Hz is your modulator frequency ?
If that is correct, check for:
Those are your major frequencies.
-Sanjay
HI Aalok,
Which kind of PWM (unipolar or bi polar) are you using?
When you are measuring your total system qualitatively in PV applications, need to check lower frequency odd harmonics( 3rd, 5th,...).
IEEE standard 1547 will give regulations on harmonics which needs to be satisfied by the inverter. So, accordingly measure harmonics.
Hi Aalok,
you Need to check the grid code requirements Standards like BDEV, VDE etc. You will find tables in those documents with the allowable values. Normally for DM noise the specifications are until 2.5 kHz (I think) for industrial and house hold nets. For CM noise I think the specification is 150 Khz.
Best regards,
Gopal
HI Aalok,
The frequency domain can be subdivided into five classes:
1) Odd interger harmonics up to 5000 Hz
2 Even integer harmonics up to 5000 Hz (rarely present)
3) Interharmonics (not integer orders) up to 5000 Hz
4) Subharmonics under 50 Hz
5) Supraharmonics which Exceed 5000 Hz to few MHz
Your work may be based on estimates that may be practical, historical or experimental. It is also important to identify the CCP from which your PV works. For a complete estimate, you try to work with the five intervals mentioned above.
Best regards.
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