Mains voltage regulation

[jerryo]

I have tried a search or two but that has not given any results.
I was wondering whether anyone has gone to the trouble of building a regulator for mains voltage. I know you can buy them, but how difficult would they be to DIY

It would simplify alot of power supply design if you already had a nice stable voltage to work with. Regulation and conditioning in one would be very nice.

Would this be too expensive for the benefits or just not worth the effort?

Just a thought

[peranders]

The simple answer is yes.

I used an equipment which dilvered 3 x 16 A and 3 x 400 VAC and this unit was a gigantic amplifier designed for measuring harmonics.

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[jerryo]

Hi peranders,
I'm actually surprised that there is not more mention of mains voltage regulation on this forum, as it would seem to me to be the best way of making life a little easier when designing/modifying and building audiophile audio equipment. Am I wrong about this?
On ebay there are a couple of regulators for sale (item numbers: 380181418336, and 380181418342) for less than £100.00 which on first glance would seem to fit the bill.
I would be interested to hear from anyone who new from experience just what was entailed in the construction of a mains regulator. It could be an interesting project.

I think I might Google a bit to see what comes up.
Any thoughts on the subject?

[TechGuy]

Originally Posted by jerryo

I have tried a search or two but that has not given any results.
I was wondering whether anyone has gone to the trouble of building a regulator for mains voltage. I know you can buy them, but how difficult would they be to DIY

It would simplify alot of power supply design if you already had a nice stable voltage to work with. Regulation and conditioning in one would be very nice.

Would this be too expensive for the benefits or just not worth the effort?

Just a thought

A PFC or Power Factor Correction circuit will provide regulation of the AC input. A PFC circuit is a special PWM controller and buck boost circuit to provide a more stable input voltage. There are lots of PFC controllers for the usual suspects (SMPS IC Manufactures) and lots of datasheets and white papers on how to include a PFC circuit in your design. Many PFC also have soft-start options to address current in-rush for the inital charge of Input/OutCapacitors used by the SMPS.

Although a PFC is a DC output device. You need to use a SMPS behind the PFC circuit. You can't use a Linear regulator because it needs AC input.

Hope this helps!

[Enzo]

It might be simpler to regulate the secondaries if you went to the trouble of regulating the mains, but really, it is not that much trouble to regulate the secondaries.

[audiojoy]

Hi have you seen this one from me, it is simple and it WORKS, disregard a lot of those comments from the non audiophiles, as long as the ear hears an improvement that's all that matters

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[TechGuy]

Originally Posted by Enzo

It might be simpler to regulate the secondaries if you went to the trouble of regulating the mains, but really, it is not that much trouble to regulate the secondaries.

Well it can be an problem if the input voltage is too low (ie temporary main voltage sag) or if the output current load is near the power supplies maximum output. To accomidate these conditions it would be necessary to increase the transform power output and increasing the secondary output voltage above your real target voltage so that it can compensate for mains voltage sags. Consider that if the input voltage drops by 10% the secondary voltage will also drop by about 10%.

A PFC implementation is probably easier in most cases since you don't have to modify the transformer or the parameters of the Switching controller. A PFC can be practically added without any modifications to the original power supply circuit since it effectively operates independantly.

[earl of sodbury]

I've used and subjectively evaluated two different types of such devices, one transformer based and designed for small computing applications, the other a 1st gen PS Audio amplifier-type device. Both had a very obvious negative nett effect to the subjective sound of my system, and I ended-up making my own passive filtration device instead.

In both cases, an inability to supply sufficient current was, I suspect, at the root of their problems.

I have heard from a friend whose opinion usually accords with my own that the current generation of PS Audio devices are very effective. I have no notion what technology they use to achieve their affect, though am aware that active regulation continues to lie at the core of their ethos.

I'm by no means convinced voltage fluctuations are an important arbiter of subjective sound in audio, and would suggest beneficial effects of preferred devices may be due largely to their potential to filter both low and high frequency anomalies on the supply line, and that well-designed passive filters, being cheaper and easier to build, should be tried first.

cheers,

[AndrewT]

how about a multi-tapped primary and use a comparator/Schmidt to control relays/FET switches to connect the appropriate tapping for the delivered supply voltage.
For 220/240Vac, twin primaries of 100,110,120 give a range of inputs of 200 to 240 in 10V steps.

Alternatively, an autotransformer with 4 output voltages of 5Vac could be used again with auto switching to get 8steps (4step up and 4step down) of 5Vac either side of the nominal input voltage. A 1kVA autoformer with tapping of 5Vac to 20Vac could supply a whole ring main to 12kVA (240Vac) or 6kVA (110Vac.

[Steve Dunlap]

You might want to look at these.

Frequency Conversion: AC Power Converter

Just one of many companies.