Designing a line filter for 220VAC for forward converter

[--BawA--]

I have to design a Line filter for 220VAC before feeding it into rectifier stage .
What is the procedure for it , i mean how to calculate the value of inductance and capacitance for filtering 220VAC .
The rectified voltage is fed into a forward converter of 200 Watt.
Any help will be highly appreciated.

 

[ArticCynda]

Since the rectified AC is presumably fed into a large tank capacitor, much of the noise on the input lines will be eliminated in that stage. To prevent high frequency switching noise from propagating back over the lines, an LC filter (series inductor and parallel capacitor) is typically used in combination with a common mode choke.

For most applications the exact inductances are not critical, and most commercially available common mode chokes are actually intended for line filtering and thus suitable for your application. Example: https://www.coilws.com/index.php?main_page=index&cPath=208_211_226_218

If you want to filter out high frequency spikes, a MOV or TVS diode in combination with a fuse and a cap from each line to earth might also be a good choice, depending on the reliability of the 220VAC supply you're intending to use.

 

[D.A.(Tony)Stewart]

January 2001, European Union have adopted the requirement for new electronic equipment that consumes more than 75 watts to meet the EN 61000-3-2 specification for harmonic content. In China, since May 1 , 2002, all electrical products used in governmental institutions must be with PFC , Japan is now developing a new project for power saving , and in the foreseeable future, the US as well , will adopt power management regulations.

1st define your harmonic requirement for maximum conducted emanations.
2nd define you peak pulse current for rated 200W load.
3rd estimate your requirements; differential filter, PFC correction, Common Mode filter ?

----added---

i.e. don't just say "I have to design a filter" without an understanding of what and how much has to be filtered. Then you will have a measure to compare your design requirements with performance.

Look at ESR (Rs) of each part of your existing design and your load, then power-on start surge current. Ripple Voltage is inverse to Peak/Avg ripple current.

State what you know.

Engineering is all about details, not throwing darts blindfolded.