Mains rectifier currents into SMPS

eem2am · 19th August 2011, 10:44 AM

Hello,

We have designed an offline SMPS for 330W maximum, Class D amplifier supply.

The mains input is 90VAC to 265VAC.
-We have a voltage doubler link for when its used in places with 90VAC........

We have NO power factor corrector stage, as it would have made it too expensive.

On continuous maximum load, at 90VAC, the mains input current consists of a train of pulses at 100Hz, and above 20 Amps in magnitude.

Obviously the input current harmonics are enormous, and we are wondering if we will get through the regulatory body requirements?

-The thing is, though we can put a Voltech PM100 power analyzer on the input and get the values of the harmonics, we cannot find what the regulatory body requirements are in respect of this.

Do you know how we can find out.?

I tried compliance-club.com but couldnt find it on there.

Google searching this also reveals nothing.

Also EN61000-3-2 does not seem to depict our situation, but just seems to talk generally about it.

marce · 19th August 2011, 11:36 AM

Look for CE or FCC based sites, I had a link to the main site, but cant find it.
There may be some relevant links from this site.
There is a threaqd regarding the EMC of these sort of designs on this section that also has a lot of relevant links.

marce · 19th August 2011, 11:38 AM

Switcher EMC design

nigelwright7557 · 19th August 2011, 11:54 PM

Here is a mains filter I used on equipment up to 30 amps.
The equipment flew through EMC testing.

http://www.ckp-railways.talktalk.net/MAINSFILTER.jpg

nigelwright7557 · 19th August 2011, 11:56 PM

Quote:

Originally Posted by eem2am

Hello,

Also EN61000-3-2 does not seem to depict our situation, but just seems to talk generally about it.

If I remember correctly audio equipment is exempt.
Up to a certain wattage if I remember correctly.

eem2am · 21st August 2011, 07:56 PM

Thanks for the links but i couldnt find info there...

I am coming to the conclusion that for offline audio SMPS's, it is simply not possible to find a document explaining what are acceptable levels of mains current harmonics flowing into a non power factor corrected SMPS for audio usage.

I believe that audio smps's don't need pfc, -but the only reason i believe that is that i see off-the-shelf offline smps's from Abletec and coldamp which are on the market and don't have PFC, despite being rated to 100's of Watts.

I do not believe that there is a document that actually states that PFC is not required for audio SMPS's.

I do not get enlightened on this by reading EN61000-3-2.

Does any reader know how audio SMPS manufacturers find out the regulations that they need to design to?

19th August 2011, 10:44 AM	#1
eem2am diyAudio Member Join Date: Jun 2011	Mains rectifier currents into SMPS Hello, We have designed an offline SMPS for 330W maximum, Class D amplifier supply. The mains input is 90VAC to 265VAC. -We have a voltage doubler link for when its used in places with 90VAC........ We have NO power factor corrector stage, as it would have made it too expensive. On continuous maximum load, at 90VAC, the mains input current consists of a train of pulses at 100Hz, and above 20 Amps in magnitude. Obviously the input current harmonics are enormous, and we are wondering if we will get through the regulatory body requirements? -The thing is, though we can put a Voltech PM100 power analyzer on the input and get the values of the harmonics, we cannot find what the regulatory body requirements are in respect of this. Do you know how we can find out.? I tried compliance-club.com but couldnt find it on there. Google searching this also reveals nothing. Also EN61000-3-2 does not seem to depict our situation, but just seems to talk generally about it.

19th August 2011, 11:54 PM	#4
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	Here is a mains filter I used on equipment up to 30 amps. The equipment flew through EMC testing. http://www.ckp-railways.talktalk.net/MAINSFILTER.jpg __________________ http://www.murtonpikesystems.co.uk PCBCAD40 pcb design software.

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19th August 2011, 11:36 AM	#2
marce diyAudio Member Join Date: Jun 2007 Location: Blackburn, Lancs	Look for CE or FCC based sites, I had a link to the main site, but cant find it. There may be some relevant links from this site. There is a threaqd regarding the EMC of these sort of designs on this section that also has a lot of relevant links.

19th August 2011, 11:38 AM	#3
marce diyAudio Member Join Date: Jun 2007 Location: Blackburn, Lancs	Switcher EMC design

21st August 2011, 07:56 PM	#6
eem2am diyAudio Member Join Date: Jun 2011	Thanks for the links but i couldnt find info there... I am coming to the conclusion that for offline audio SMPS's, it is simply not possible to find a document explaining what are acceptable levels of mains current harmonics flowing into a non power factor corrected SMPS for audio usage. I believe that audio smps's don't need pfc, -but the only reason i believe that is that i see off-the-shelf offline smps's from Abletec and coldamp which are on the market and don't have PFC, despite being rated to 100's of Watts. I do not believe that there is a document that actually states that PFC is not required for audio SMPS's. I do not get enlightened on this by reading EN61000-3-2. Does any reader know how audio SMPS manufacturers find out the regulations that they need to design to?

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