Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Power Conversion Electronics

I just purchase a Silverstone Power Supply Unit (PSU) for my PC.

I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).

Since it's a new unit I dare not to open up the PSU to see what type
of electronics they are using.

So I post the question here ----

Can anyone tell me what type of Power Conversion Electronic Devices
they use in those high PFC rating PSU?

Thank you all !!!
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Default Power Conversion Electronics

On Sun, 26 Apr 2009 02:20:26 -0700 (PDT), pg
wrote:

I just purchase a Silverstone Power Supply Unit (PSU) for my PC.

I am amaze with the PFC (Power Factor Correction) rating
of over 0.96, which, according to some indicators,
means it's 96% efficient. (4% wastage as heat).


PFC and efficiency are not the same thing.
http://en.wikipedia.org/wiki/Power_factor_correction
http://en.wikipedia.org/wiki/Energy_...ion_efficiency

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Default Power Conversion Electronics

pg wrote:
I just purchase a Silverstone Power Supply Unit (PSU) for my PC.

I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).

Since it's a new unit I dare not to open up the PSU to see what type
of electronics they are using.

So I post the question here ----

Can anyone tell me what type of Power Conversion Electronic Devices
they use in those high PFC rating PSU?

Thank you all !!!


Something like this, perhaps

http://www.onsemi.com/pub_link/Collateral/NCP1653-D.PDF

Sylvia.
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Default Power Conversion Electronics

On Apr 26, 2:33*am, Ken wrote:
On Sun, 26 Apr 2009 02:20:26 -0700 (PDT), pg
wrote:

I just purchase a Silverstone Power Supply Unit (PSU) for my PC.


I am amaze with the PFC (Power Factor Correction) rating
of over 0.96, which, according to some indicators,
means it's 96% efficient. (4% wastage as heat).


PFC and efficiency are not the same thing.http://en.wikipedia.org/wiki/Power_f...ion_efficiency


Many thanks for the info !!
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Default Power Conversion Electronics

On Sun, 26 Apr 2009 02:20:26 -0700, pg rearranged some electrons to say:

I just purchase a Silverstone Power Supply Unit (PSU) for my PC.

I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).

Since it's a new unit I dare not to open up the PSU to see what type of
electronics they are using.

So I post the question here ----

Can anyone tell me what type of Power Conversion Electronic Devices they
use in those high PFC rating PSU?

Thank you all !!!


0.96 power factor does not mean 96% efficient. But, to answer your
question, active power factor correction means that the front end of the
power supply tries to keep the phase between the voltage and current
waveforms as small as possible.


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Default Power Conversion Electronics

Sylvia Else wrote:
pg wrote:
I just purchase a Silverstone Power Supply Unit (PSU) for my PC.

I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).

Since it's a new unit I dare not to open up the PSU to see what type
of electronics they are using.

So I post the question here ----

Can anyone tell me what type of Power Conversion Electronic Devices
they use in those high PFC rating PSU?

Thank you all !!!


Something like this, perhaps

http://www.onsemi.com/pub_link/Collateral/NCP1653-D.PDF

Sylvia.


Hmm.... I wonder how those would handle an input in the form of a
"modified sine wave", which would more accurately be described as a
modified square wave, as typically produced by cheaper UPSs.

An ordinary PC PS wouldn't notice the difference.

Sylvia.
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Default Power Conversion Electronics

On Apr 26, 7:08*am, Sylvia Else wrote:
Sylvia Else wrote:
pg wrote:
I just purchase a Silverstone Power Supply Unit (PSU) for my PC.


I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).


Since it's a new unit I dare not to open up the PSU to see what type
of electronics they are using.


So I post the question here ----


Can anyone tell me what type of Power Conversion Electronic Devices
they use in those high PFC rating PSU?


Thank you all !!!


Something like this, perhaps


http://www.onsemi.com/pub_link/Collateral/NCP1653-D.PDF


Sylvia.


Hmm.... I wonder how those would handle an input in the form of a
"modified sine wave", which would more accurately be described as a
modified square wave, as typically produced by cheaper UPSs.

An ordinary PC PS wouldn't notice the difference.


Most power factor correction circuit will run on a rounded off square
wave without any trouble. In the short term, they watch the input
voltage and match the current to that. They don't make their own sine
function to match the current to.


Sylvia.


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Default Power Conversion Electronics

On Apr 26, 5:32*am, david wrote:
On Sun, 26 Apr 2009 02:20:26 -0700, pg rearranged some electrons to say:

I just purchase a Silverstone Power Supply Unit (PSU) for my PC.


I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).


Since it's a new unit I dare not to open up the PSU to see what type of
electronics they are using.


So I post the question here ----


Can anyone tell me what type of Power Conversion Electronic Devices they
use in those high PFC rating PSU?


Thank you all !!!


0.96 power factor does not mean 96% efficient. *But, to answer your
question, *active power factor correction means that the front end of the
power supply tries to keep the phase between the voltage and current
waveforms as small as possible.


It also tries not to draw any current at harmonics. It is unfortunate
that one term is now used for two effects but we are stuck with it.
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Default Power Conversion Electronics

On Apr 26, 11:33*am, MooseFET wrote:
It also tries not to draw any current at harmonics. *It is unfortunate
that one term is now used for two effects but we are stuck with it.


Displacement Factor is the fudamental only.

Tim
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Default Power Conversion Electronics

pg wrote:

I just purchase a Silverstone Power Supply Unit (PSU) for my PC.

I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).

Since it's a new unit I dare not to open up the PSU to see what type
of electronics they are using.

So I post the question here ----

Can anyone tell me what type of Power Conversion Electronic Devices
they use in those high PFC rating PSU?


Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items. PFC can be either active or
passive, but usually alters the highly capacitive input of SMPSs.

Google "PFC".


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Default Power Conversion Electronics -- Power-factor correction forswitchmode PSes

On Sun, 26 Apr 2009 19:39:23 +1000, Sylvia Else wrote:

http://www.onsemi.com/pub_link/Collateral/NCP1653-D.PDF
Sylvia.


Most interesting! I'd been wondering how it's done. Basic circuit is
quite simple. Although I didn't read carefully, it seems that only at the
end did I learn that it can provide 300 VDC to the inverter; wasn't sure
until then whether the complete circuit was for low voltage output.

I'd guess that total component cost is pretty modest.

Regards,
nb
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Default Power Conversion Electronics


"UCLAN"

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.


** OK so far.

PFC can be either active or passive,


** Hmmmm...

but usually alters the highly capacitive input of SMPSs.



** TOTAL ******** !!!

They are not capacitive, there is no phase angle.

Active PFCs correct WAVEFORM distortion.



....... Phil





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Default Power Conversion Electronics

On Mon, 27 Apr 2009 12:22:11 +1000, "Phil Allison"
wrote:


"UCLAN"

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.


** OK so far.

PFC can be either active or passive,


** Hmmmm...

but usually alters the highly capacitive input of SMPSs.



** TOTAL ******** !!!

They are not capacitive, there is no phase angle.

Active PFCs correct WAVEFORM distortion.



...... Phil





Take you meds and lie down for a while. What he said was perfectly
reasonable.

John


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Default Power Conversion Electronics


"John Larkin"
"Phil Allison"

"UCLAN"

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.


** OK so far.

PFC can be either active or passive,


** Hmmmm...

but usually alters the highly capacitive input of SMPSs.



** TOTAL ******** !!!

They are not capacitive, there is no phase angle.

Active PFCs correct WAVEFORM distortion.



Take you meds and lie down for a while.



** Drop dead.


What he said was perfectly reasonable.



** It was totally FALSE , you insane ****head.




...... Phil




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Default Power Conversion Electronics

Phil Allison wrote:
"UCLAN"

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.


** OK so far.

PFC can be either active or passive,


** Hmmmm...

but usually alters the highly capacitive input of SMPSs.



** TOTAL ******** !!!

They are not capacitive, there is no phase angle.

Active PFCs correct WAVEFORM distortion.


If you take the waveform of the current into a conventional SMPS, and
split it into its harmonics, you'll find that the fundamental leads the
voltage. This because the PS's capacitor is charged during the rising
side of the input waveform.

Looks like a phase angle to me.

By making the current proportional to the voltage, active PFCs both
minimise the waveform distortion, and correct the phase angle.

Sylvia.


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Default Power Conversion Electronics

On Sun, 26 Apr 2009 02:20:26 -0700, pg wrote:

I just purchase a Silverstone Power Supply Unit (PSU) for my PC.

I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).


As others have already pointed out, 0.96 power factor doesn't mean 96%
efficient.

Power factor does have a slight impact upon efficiency, as a low power
factor increases the energy wasted in the power lines, but this is small
compared to the energy actually used by the supply.

Since it's a new unit I dare not to open up the PSU to see what type
of electronics they are using.

So I post the question here ----

Can anyone tell me what type of Power Conversion Electronic Devices
they use in those high PFC rating PSU?


Active PFC involves using a boost converter whose current draw is
sinusoidal and in phase with the voltage.

For more detail than you probably wanted to know, see:

http://www.onsemi.com/pub_link/Collateral/HBD853-D.PDF

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Default Power Conversion Electronics

On Apr 26, 8:29*pm, Nobody wrote:
On Sun, 26 Apr 2009 02:20:26 -0700, pg wrote:
I just purchase a Silverstone Power Supply Unit (PSU) for my PC.


I am amaze with the PFC (Power Factor Correction) rating of over 0.96,
which, according to some indicators, means it's 96% efficient. (4%
wastage as heat).


As others have already pointed out, 0.96 power factor doesn't mean 96%
efficient.

Power factor does have a slight impact upon efficiency, as a low power
factor increases the energy wasted in the power lines, but this is small
compared to the energy actually used by the supply.

Since it's a new unit I dare not to open up the PSU to see what type
of electronics they are using.


So I post the question here ----


Can anyone tell me what type of Power Conversion Electronic Devices
they use in those high PFC rating PSU?


Active PFC involves using a boost converter whose current draw is
sinusoidal and in phase with the voltage.

For more detail than you probably wanted to know, see:

* * * *http://www.onsemi.com/pub_link/Collateral/HBD853-D.PDF


Thanks a lot for the link !!
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Default Power Conversion Electronics

Phil Allison wrote:

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.


** OK so far.


Gee, thanks. [Red flag warning!!!]

PFC can be either active or passive,


** Hmmmm...


Careful, a hint of ignorance is showing.

but usually alters the highly capacitive input of SMPSs.


** TOTAL ******** !!!

They are not capacitive, there is no phase angle.


And it's finally out. He's a total loon.

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]
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Default Power Conversion Electronics


"UCLAN" = the Original Monkey's Uncle.

Phil Allison wrote:

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.


** OK so far.


Gee, thanks. [Red flag warning!!!]

PFC can be either active or passive,


** Hmmmm...


Careful, a hint of ignorance is showing.

but usually alters the highly capacitive input of SMPSs.


** TOTAL ******** !!!

They are not capacitive, there is no phase angle.


And it's finally out. He's a total loon.



** This arrogant IMBECILE is about to get a lesson !!!


There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input.



** And because they are * AFTER * the rectifiers there is NO cap
reactance or phase angle effects involved.


They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value.



** The caps can only draw current when the diodes are forward biased and
cannot pass any current back to the supply.

Negates all capacitive reactance effects.


Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point),



** 100% ****ING WRONG !!!!!!!!!!!

The caps can only draw charging current when the AC supply voltage is
greater than the voltage already on the cap - so ( aside from the very
first cycle ) they charge at AC voltage peaks ONLY !!!!!!!!


and draw their least amount of current when charged to their highest
point,



** Insane CRAP !!!!!!!!!!!!!!!

Even one moment's intelligent thought shows that simply CANNOT be true.


the current waveform
*leads* the voltage waveform by 90 degrees.



** Absolute ******** !!!

Max current draw **coincides** with peak AC voltage - there is ZERO
phase angle.

Time for you to go play with the demented Orang-utans

- DICKHEAD !!




...... Phil





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Default Power Conversion Electronics

On Mon, 27 Apr 2009 17:14:51 +1000, "Phil Allison"
wrote:


"UCLAN" = the Original Monkey's Uncle.

Phil Allison wrote:

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.

** OK so far.


Gee, thanks. [Red flag warning!!!]

PFC can be either active or passive,

** Hmmmm...


Careful, a hint of ignorance is showing.

but usually alters the highly capacitive input of SMPSs.

** TOTAL ******** !!!

They are not capacitive, there is no phase angle.


And it's finally out. He's a total loon.



** This arrogant IMBECILE is about to get a lesson !!!



Maybe, but you are still a total loon (!!!)



Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point),



** 100% ****ING WRONG !!!!!!!!!!!


When one uses this many apostrophies, it is customary to ask
Vanna for a vowel and pay for each. You have not done so,
and so it is detracting from your attempted point.




The caps can only draw charging current when the AC supply voltage is
greater than the voltage already on the cap - so ( aside from the very
first cycle ) they charge at AC voltage peaks ONLY !!!!!!!!


Ok !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!



Time for you to go play with the demented Orang-utans


Wait, are you saying we now have a petting zoo?

cool!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!

Which cage are you in, I will stop by and throw you a
peanut. And some lithium.


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Default Power Conversion Electronics


"kony"


** No man is an island ......




..... Phil


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Default Power Conversion Electronics


kony wrote:

Which cage are you in, I will stop by and throw you a
peanut. And some lithium.



Throw him some Dilitium. His mind needs a recharge. ;-)




--
You can't have a sense of humor, if you have no sense!
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Default Power Conversion Electronics

Phil Allison wrote:

** This arrogant IMBECILE is about to get a lesson !!!


I suggest you do a little reading. Start with:

http://www.fairchildsemi.com/an/AN/AN-42047.pdf

Until then, I suggest you get back on your meds - quickly.
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Default Power Conversion Electronics

John Larkin wrote:
"Phil Allison" wrote:

.... snip ...

** TOTAL ******** !!!

They are not capacitive, there is no phase angle.

Active PFCs correct WAVEFORM distortion.


Take you meds and lie down for a while. What he said was
perfectly reasonable.


Also, kindly give a complete description about how you determine
that an isolated waveform is distorted?

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: http://cbfalconer.home.att.net
Try the download section.


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Default Power Conversion Electronics

Phil Allison wrote:
"John Larkin"

.... snip ...

Take you meds and lie down for a while.


** Drop dead.

What he said was perfectly reasonable.


** It was totally FALSE , you insane ****head.


I suspect he failed to follow your advice, above. It doesn't
appear to have improved his language, either.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: http://cbfalconer.home.att.net
Try the download section.




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"UCLAN" = Monkey's Uncle


** This arrogant IMBECILE has had his lesson.

But he didn't learn anything -

cos he is a congenital ****wit.




....... Phil




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Default Power Conversion Electronics

On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]


As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.

PA could easily put at end to this argument by enlightening everyone
with his own example ...

http://groups.google.com/group/aus.e...e=source&hl=en

.... but instead he chooses to elevate himself by demeaning others.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
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Default Power Conversion Electronics



Franc Zabkar wrote:

On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]


As much as I dislike the man, he's right.


He is. Actually, from modelling, I've found a big hulky inductor between the rectifier and
storage caps is pretty good at correcting harmonics. Trouble is, they're big, heavy and
expensive.

Sadly active PFC produces even more RF 'hash' that needs to be dealt with.


Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.

PA could easily put at end to this argument by enlightening everyone
with his own example ...

http://groups.google.com/group/aus.e...e=source&hl=en

... but instead he chooses to elevate himself by demeaning others.


Sadly so.

Graham

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Franc Zabkar wrote:
On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]


As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.


It does show that the current leads - look at how it's not positioned
symmetrically about the 90 degree point, for example. It's not a 90
degree lead, of course, but it's still a lead.

Mind you, I think the graph is wrong. When it's flowing, the current
into a capactor should be proportional to the rate of change of voltage.
So you should see a rapid rise once the input voltage goes above that
already on the capacitor, followed by a progressive reduction towards
zero (plus the load current) at the voltage peak. I suppose you'd get
something closer to what's shown if there were an inductor in series
with the supply.

Sylvia.
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Default Power Conversion Electronics

On Wed, 29 Apr 2009 12:28:36 +1000, Sylvia Else
put finger to keyboard and composed:

Franc Zabkar wrote:
On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]


As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.


It does show that the current leads - look at how it's not positioned
symmetrically about the 90 degree point, for example. It's not a 90
degree lead, of course, but it's still a lead.


A bigger capacitor would result in less ripple, which means less lead.
If you were relying on intuition alone, you would expect that the PF
would move closer to unity. In fact the PF actually becomes worse.

See the calculations in Phil's example.

- Franc Zabkar
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Default Power Conversion Electronics

Franc Zabkar wrote:
On Wed, 29 Apr 2009 12:28:36 +1000, Sylvia Else
put finger to keyboard and composed:

Franc Zabkar wrote:
On Sun, 26 Apr 2009 22:48:56 -0700, UCLAN put
finger to keyboard and composed:

There is a big 400vdc capacitor (or two 200vdc caps in series) just after
input rectifiers on the AC input. Note C5 and C6 on:

http://www.pavouk.org/hw/en_atxps.html

They charge to the peak value of the input
AC voltage, or 1.414 times the RMS value. Since the cap(s) draw their maximum
current when at lowest charge (zero cross-over point), and draw their least
amount of current when charged to their highest point, the current waveform
*leads* the voltage waveform by 90 degrees. [Maximum current is at the same
time as minimum voltage; minimum current is at the same time as maximum voltage.]
As much as I dislike the man, he's right.

Look at Fig 6 on page 2 of the application note you linked to
elsewhere in this thread.

It does show that the current leads - look at how it's not positioned
symmetrically about the 90 degree point, for example. It's not a 90
degree lead, of course, but it's still a lead.


A bigger capacitor would result in less ripple, which means less lead.
If you were relying on intuition alone, you would expect that the PF
would move closer to unity.


In fact the PF actually becomes worse.


With a larger capacitor, you get less lead, but higher instantaneous
currents. My intuition would be that the net result is far from obvious.

However, the higher current for shorter periods means higher harmonic
currents, which don't contribute to the power, so it wouldn't surprise
me that the PF would go down.

Sylvia.
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