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From: MooseFET on 5 Jan 2010 09:20
On Jan 4, 6:37 pm, "Tim Williams" <tmoran...(a)charter.net> wrote:
> "MooseFET" <kensm...(a)rahul.net> wrote in message
>
> news:415e4301-e21b-45c5-a78d-20cd9b09748e(a)v25g2000yqk.googlegroups.com...
>
> > When the number of poles becomes infinite, the harmonics all drop to
> > zero.
> > Beyond the infinite number, there is no further improvement.
> > I hope this helps.
>
> How can there ever not be harmonics, either voltage or current, input or
> output, when transforming three phase to DC?  I think a simple energy budget
> shows this is necessary.
>
> Ignoring the three phase source, if you start with n equal voltage, equally
> spaced phases, you will get harmonics of 2n and higher, with a current pulse
> roughly 1/n of the waveform per phase.

I think you missed that the source is 3 phase power and we are
constructing
more phases with the transformers. If so the rest won't be needed as
you
will already see it.

Imagine that you have a synchronous motor running on 3 phase. The 3
phase power
makes a rotating magnetic field that is of constant strength.

Now imagine that the motor is moving an infinitely fine commutator
under some
brushes such that the contacts are always at the voltage peaks. This
is the
infinite number of poles case.

From: Paul Keinanen on 5 Jan 2010 09:41
On Tue, 29 Dec 2009 07:17:31 -0600, "Tim Williams"
<tmoranwms(a)charter.net> wrote:

>PFC is a flyback thing. But flybacks suck over 100W, where forward looks
>better. But forward sucks over wide duty cycle ranges. What do they do,
>just bigger flybacks? Nothing at all?

Digging deeper into my old archives, the ON Semi PFC Handbook
http://www.onsemi.com/pub_link/Collateral/HBD853-D.PDF might also be
useful for single phase applications up to 300 W.

From: krw on 5 Jan 2010 18:26
On Tue, 05 Jan 2010 13:06:43 GMT, Jan Panteltje
<pNaonStpealmtje(a)yahoo.com> wrote:

>On a sunny day (Mon, 4 Jan 2010 18:19:15 -0800 (PST)) it happened MooseFET
><kensmith(a)rahul.net> wrote in
><b4f80fb0-b390-4a51-949b-00073266a8f3(a)s31g2000yqs.googlegroups.com>:

<snip>

>>> An interesting solution, never seen that before, maybe I am too old:-)
>>... Or maybe too young. Back when rectifiers couldn't handle the
>>power,
>>you needed more diodes and a way to share the current so doing this
>>didn't
>>add parts.
>
>mmm I dunno,
>designed something for the army that a had selenium rectifier in it..

I love the smell of burning selenium in the morning.
From: JosephKK on 19 Jan 2010 07:26
On Sat, 16 Jan 2010 13:24:22 -0800, Fred Abse <excretatauris(a)invalid.invalid> wrote:

>On Sun, 03 Jan 2010 11:51:44 -0800, JosephKK wrote:
>
>> I am playing around with modeling 3-phase rectifiers. I think PFC
>> would be a real good thing for 3-phase rectifiers. May be more than
>> a tad interesting to implement though.
>
>Interesting to do if you need to implement synchronous regeneration back
>into the supply from a big variable frequency drive.
>
>
>Following on from your posted simulations, I did this, it's a simplified
>3 phase, 100 amp PSU circuit from a VFD. Regeneration circuitry omitted.
>Power factor varies from 0.26 at no load to 0.94 at full load.
>
>Plot definition file and log file included.
>
>File 3phrect.asc
>
>
>Version 4
>SHEET 1 1652 864
>WIRE 192 -384 64 -384
>WIRE 288 -384 192 -384
>WIRE 560 -384 288 -384
>WIRE 624 -384 560 -384
>WIRE 944 -384 624 -384
>WIRE 64 -288 64 -384
>WIRE 192 -288 192 -384
>WIRE 288 -288 288 -384
>WIRE -192 -64 -688 -64
>WIRE 288 -64 288 -224
>WIRE 288 -64 -112 -64
>WIRE -688 -48 -688 -64
>WIRE 624 -16 624 -384
>WIRE 752 -16 624 -16
>WIRE -688 32 -816 32
>WIRE 624 32 624 -16
>WIRE 752 32 752 -16
>WIRE 944 32 944 -384
>WIRE -176 112 -688 112
>WIRE 192 112 192 -224
>WIRE 192 112 -96 112
>WIRE -688 144 -688 112
>WIRE 624 160 624 96
>WIRE 752 160 752 112
>WIRE 752 160 624 160
>WIRE -816 256 -816 32
>WIRE -688 256 -688 224
>WIRE -688 256 -816 256
>WIRE -192 288 -688 288
>WIRE 64 288 64 -224
>WIRE 64 288 -112 288
>WIRE -688 368 -688 288
>WIRE 64 368 64 288
>WIRE 192 368 192 112
>WIRE 288 368 288 -64
>WIRE -816 496 -816 256
>WIRE -752 496 -816 496
>WIRE -688 496 -688 448
>WIRE -688 496 -752 496
>WIRE 64 512 64 432
>WIRE 192 512 192 432
>WIRE 192 512 64 512
>WIRE 288 512 288 432
>WIRE 288 512 192 512
>WIRE 544 512 288 512
>WIRE 624 512 624 160
>WIRE 624 512 544 512
>WIRE 944 512 944 112
>WIRE 944 512 624 512
>WIRE -752 544 -752 496
>FLAG 544 512 VLneg
>FLAG 560 -384 VLpos
>FLAG -752 544 0
>SYMBOL diode 48 432 M180
>WINDOW 0 24 72 Left 0
>WINDOW 3 24 0 Left 0
>SYMATTR InstName D1
>SYMATTR Value FWD
>SYMBOL diode 176 432 M180
>WINDOW 0 24 72 Left 0
>WINDOW 3 24 0 Left 0
>SYMATTR InstName D2
>SYMATTR Value FWD
>SYMBOL diode 272 432 M180
>WINDOW 0 24 72 Left 0
>WINDOW 3 24 0 Left 0
>SYMATTR InstName D3
>SYMATTR Value FWD
>SYMBOL diode 48 -224 M180
>WINDOW 0 24 72 Left 0
>WINDOW 3 24 0 Left 0
>SYMATTR InstName D4
>SYMATTR Value FWD
>SYMBOL diode 176 -224 M180
>WINDOW 0 24 72 Left 0
>WINDOW 3 24 0 Left 0
>SYMATTR InstName D5
>SYMATTR Value FWD
>SYMBOL diode 272 -224 M180
>WINDOW 0 24 72 Left 0
>WINDOW 3 24 0 Left 0
>SYMATTR InstName D6
>SYMATTR Value FWD
>SYMBOL ind2 -96 304 M270
>WINDOW 0 32 56 VTop 0
>WINDOW 3 5 56 VBottom 0
>SYMATTR InstName L9
>SYMATTR Value 220u
>SYMATTR Type ind
>SYMBOL ind2 -80 128 M270
>WINDOW 0 32 56 VTop 0
>WINDOW 3 5 56 VBottom 0
>SYMATTR InstName L10
>SYMATTR Value 220u
>SYMATTR Type ind
>SYMBOL ind2 -96 -48 M270
>WINDOW 0 32 56 VTop 0
>WINDOW 3 5 56 VBottom 0
>SYMATTR InstName L11
>SYMATTR Value 220u
>SYMATTR Type ind
>SYMBOL cap 608 32 R0
>SYMATTR InstName C1
>SYMATTR Value 5600u
>SYMATTR SpiceLine V=400 Rser=.5
>SYMBOL current 944 32 R0
>WINDOW 123 0 0 Left 0
>WINDOW 39 24 116 Left 0
>SYMATTR SpiceLine load
>SYMATTR InstName I1
>SYMATTR Value 0
>SYMBOL voltage -688 48 R180
>WINDOW 123 0 0 Left 0
>WINDOW 39 24 -12 Left 0
>SYMATTR SpiceLine Rser=.1
>SYMATTR InstName V1
>SYMATTR Value SINE(0 163.293 60 0 0 0)
>SYMBOL voltage -688 240 R180
>WINDOW 123 0 0 Left 0
>WINDOW 39 24 76 Left 0
>SYMATTR SpiceLine Rser=.1
>SYMATTR InstName V2
>SYMATTR Value SINE(0 163.293 60 0 0 120)
>SYMBOL voltage -688 464 R180
>WINDOW 123 0 0 Left 0
>WINDOW 39 24 76 Left 0
>SYMATTR SpiceLine Rser=.1
>SYMATTR InstName V3
>SYMATTR Value SINE(0 163.293 60 0 0 240)
>SYMBOL res 736 16 R0
>SYMATTR InstName R1
>SYMATTR Value 5.6k
>TEXT 416 24 Left 0 !.ic v(VLpos) 140\n.ic v(VLneg) -140 \n *precharge
>TEXT -680 -344 Left 0 !.model FWD D Ron=10m Roff=100e6 Vfwd=0.35 Vrev=600
>TEXT -512 536 Left 0 !.tran 0 1 0
>TEXT -512 584 Left 0 !.meas tran TP avg(V(n001)*I(V1)) *True power
>TEXT -512 640 Left 0 !.meas tran VRMS rms(V(n001))
>TEXT -512 688 Left 0 !.meas tran IRMS rms(I(V1))
>TEXT -512 744 Left 0 !.meas tran AP avg(VRMS*IRMS) *Apparent power
>TEXT -512 800 Left 0 !.meas tran PF param TP/AP *Power factor
>TEXT -616 0 Left 0 ;200V between phases
>TEXT 768 192 Left 0 !.step I1 0 100 10
>TEXT -232 -144 Left 0 !k1 L9 L10 L11 0.5
>TEXT 696 576 Left 0 !.meas tran VL avg(v(VLpos)-v(VLneg))\n.meas tran Pout param VL*I(I1)
>TEXT -200 -184 Left 0 ;Line reactor
>
>
>File 3phrect.plt
>
>[Transient Analysis]
>{
> Npanes: 3
> Active Pane: 2
> {
> traces: 1 {34603010,0,"I(V1)"}
> X: (' ',1,0,0.1,1)
> Y[0]: (' ',0,-120,20,120)
> Y[1]: ('_',0,1e+308,0,-1e+308)
> Amps: (' ',0,0,0,-120,20,120)
> Log: 0 0 0
> GridStyle: 1
> },
> {
> traces: 1 {524291,0,"V(n001)"}
> X: (' ',1,0,0.1,1)
> Y[0]: (' ',0,-180,30,180)
> Y[1]: ('_',0,1e+308,0,-1e+308)
> Volts: (' ',0,0,0,-180,30,180)
> Log: 0 0 0
> GridStyle: 1
> },
> {
> traces: 1 {524292,0,"V(VLpos,VLneg)"}
> X: (' ',1,0,0.1,1)
> Y[0]: (' ',0,225,5,280)
> Y[1]: ('_',0,1e+308,0,-1e+308)
> Volts: (' ',0,0,0,225,5,280)
> Log: 0 0 0
> GridStyle: 1
> }
>}
>
>
>Log file from a run:
>
>Circuit: * H:\Spice\test.asc
>
>.step i1=0
>Direct Newton iteration for .op point succeeded.
>.step i1=10
>.step i1=20
>.step i1=30
>.step i1=40
>.step i1=50
>.step i1=60
>.step i1=70
>.step i1=80
>.step i1=90
>.step i1=100
>
>
>Measurement: tp
> step AVG(v(n001)*i(v1)) FROM TO
> 1 4.92903 0 1
> 2 870.501 0 1
> 3 1719.76 0 1
> 4 2568.47 0 1
> 5 3406.9 0 1
> 6 4215.87 0 1
> 7 5002.64 0 1
> 8 5809.35 0 1
> 9 6569.61 0 1
> 10 7357.99 0 1
> 11 8134.66 0 1
>
>Measurement: vrms
> step RMS(v(n001)) FROM TO
> 1 114.699 0 1
> 2 114.415 0 1
> 3 113.542 0 1
> 4 112.69 0 1
> 5 111.896 0 1
> 6 111.095 0 1
> 7 110.262 0 1
> 8 109.522 0 1
> 9 108.701 0 1
> 10 107.999 0 1
> 11 107.301 0 1
>
>Measurement: irms
> step RMS(i(v1)) FROM TO
> 1 0.165922 0 1
> 2 10.1219 0 1
> 3 18.3089 0 1
> 4 25.879 0 1
> 5 33.501 0 1
> 6 41.1342 0 1
> 7 48.7225 0 1
> 8 56.68 0 1
> 9 64.3137 0 1
> 10 72.3274 0 1
> 11 80.387 0 1
>
>Measurement: ap
> step AVG(vrms*irms) FROM TO
> 1 19.0311 0 1
> 2 1158.09 0 1
> 3 2078.83 0 1
> 4 2916.3 0 1
> 5 3748.64 0 1
> 6 4569.8 0 1
> 7 5372.22 0 1
> 8 6207.71 0 1
> 9 6990.94 0 1
> 10 7811.25 0 1
> 11 8625.57 0 1
>
>Measurement: pf
> step tp/ap
> 1 0.258999
> 2 0.751669
> 3 0.827272
> 4 0.880729
> 5 0.908837
> 6 0.92255
> 7 0.931206
> 8 0.935827
> 9 0.939733
> 10 0.941973
> 11 0.943087
>
>Measurement: vl
> step AVG(v(vlpos)-v(vlneg)) FROM TO
> 1 280.846 0 1
> 2 269.649 0 1
> 3 264.674 0 1
> 4 261.622 0 1
> 5 259.052 0 1
> 6 256.417 0 1
> 7 253.744 0 1
> 8 251.29 0 1
> 9 248.669 0 1
> 10 246.405 0 1
> 11 244.15 0 1
>
>Measurement: pout
> step vl*i(i1)
> 1 0
> 2 2696.49
> 3 5293.48
> 4 7848.67
> 5 10362.1
> 6 12820.9
> 7 15224.6
> 8 17590.3
> 9 19893.5
> 10 22176.5
> 11 24415
>
>
>Date: Sat Jan 16 05:28:55 2010
>Total elapsed time: 21.350 seconds.
>
>tnom = 27
>temp = 27
>method = modified trap
>totiter = 34546
>traniter = 34542
>tranpoints = 15714
>accept = 10511
>rejected = 5203
>matrix size = 11
>fillins = 12
>solver = Normal
>Matrix Compiler1: off
>Matrix Compiler2: off

Thanks Fred. I am learning some stuff about spice from this.
It seems the power factor is not so bad as the harmonics.
From: JosephKK on 24 Jan 2010 12:14
On Sun, 24 Jan 2010 08:04:24 -0800, Fred Abse <excretatauris(a)invalid.invalid> wrote:

>On Tue, 19 Jan 2010 04:26:37 -0800, JosephKK wrote:
>
>> Thanks Fred. I am learning some stuff about spice from this. It seems the
>> power factor is not so bad as the harmonics.
>
>The way true and apparent power were calculated should include the effect
>of harmonics.

While is most certainly does include the power in the harmonics, it does not
calculate the spectral power of each of the various harmonics. I am
interested in the harmonic power by harmonic number.
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