Author Topic: Building a 6kw pure sine wave inverter using power jack boards part1 transformer  (Read 80843 times)

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clockmanFRA

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Warts time.

Making that extra 4th 1.8mm diameter 118 winding left me on paper, just enough space to get 14 turns of 50mm/2 through the centre hole and lay tidy, in theory.

Nope it didn't work out, so I ended up with the 14 turns with 1 and a 1/2 turns overwrapping itself.  ::)



However, I spent some time re=reading 'oztules' notes again.......
 "To get the thick primary in there... 14 turns will be difficult, maybe more iron, and less turns will allow you get to a stage where the turns are possible with the smaller hole you have.... note my photo. 14 turns of wire took up the whole hole with a single layer.... more would have made it messy, and hard to get a bolt through to hold the thing down."

9004-1

I still have enough space to get a bolt down the middle of my toroid, and I read this........
 "Remember, a turn is counted as a wire going through the hole. Don't care how it ends up, but has to be through the hole... that's where the magic happens. So this takes away the confusion of half turns at the start or finish.... if it goes through the hole, it counts as 1 turn. If you only count the wires in the core, you will be fine."

And a photo of another 'oztules' torroid with more turns and some overwrapping through the centre hole...


So I think my toroid will be okay.?  :-\

I also read this...... " Don't epoxy the  75mmsq cable... not necessary in any way. It is both silent because of the sheath, and vibration is not a problem for the same reason."
So no need for me to wrap and lock those 14 turns, although I just recently obtained some spare Potting compound used in underground Big cable junction boxes.
At the same time I obtained some 50mm/2 straight through connectors and I solder those.

 My first Pic of my toroid above, shows a joint on the last turn of my 14 turns, as although I started winding half way I ended up with half a turn out.  :'(

I will use 50mm/2 Tri rated/car battery/welder flexible cable for the bit from the toroid to the PJ Boards.

Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

clockmanFRA

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"Whats the voltage on the primary,  now with 240v on secondary??"

I have just done the test.

220vac and light bulb on the 118 turns x 4off and 165.9vac going in the secondary.

9006-0

And meter attached to the 14 turns, primary is 19.65vac.

9007-1

Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

oztules

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Once you get the thing going, short the light out so you can drive the secondary with the full 240/220v. You need the light to get it going, after that it will draw almost nothing direct coupled to the mains...... very doubtful you will get it going without the globe in series though... inrush current is huge for these things anywhere near zero crossing conditions.

................oztules
Flinders Island Australia

clockmanFRA

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Yes, thanks for that 'oztules'.

'IT LIVES, IT lives I tell you'.... well once the secondary was taking the full 236vac, it was very very quietly softly humming.



The primary 14 turns was showing 28vac.

9009-1

Hmm, Not sure if that's good or Bad?
 You did say " so 30 odd volts is what we want.... "
« Last Edit: July 29, 2015, 11:07:26 AM by clockmanFRA »
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

oztules

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one more turn would be better, but it will be fine as it is.... you will do better with flat batteries :)... you have more head room.

Your cores are slightly less cross section than mine from the looks. I would get 2.28v/turn, your  getting 2.0... so your actually running a 118x2=236v transformer.

I fully expected your cores to be bigger/better than my chinese ones... but not so.

The idle current will be interesting to see when you hook it up. It should be ideal for 220v use, as it will be further away from saturation then...... mine are 240v units, so you may have hit the right turns for 220v.

Next....... lets see what she'll do mister :) :) :)

Don't forget to use the ecore ferrite filter... you should do around 25-30 watts for a monster transformer and electronics draw..


......oztules
Flinders Island Australia

niall2

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i,ve no idea technically whats going on here but its fascinating to watch .....good luck Clockman

clockmanFRA

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i,ve no idea technically whats going on here but its fascinating to watch .....good luck Clockman

Thanks niall2. I sort of see the principal and concept of the 8 to 1 ratio and how the mass of the toroid core is significant.
My manufacture in the UK could only go to 60mm max height/thickness.

I think if I was doing another, I would go for 3 toroid cores at 60mm thick but with 200mm od and a 100mm centre hole instead of my present 190mm diameter and 90mm hole.

But I feel sure the 'OZ animal Inverter' that I am building with the maestro's guidance, will do what I want, and put the SMA SI6 to shame.


Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

clockmanFRA

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one more turn would be better, but it will be fine as it is.... you will do better with flat batteries :)... you have more head room.

Your cores are slightly less cross section than mine from the looks. I would get 2.28v/turn, your  getting 2.0... so your actually running a 118x2=236v transformer.

I fully expected your cores to be bigger/better than my chinese ones... but not so.

The idle current will be interesting to see when you hook it up. It should be ideal for 220v use, as it will be further away from saturation then...... mine are 240v units, so you may have hit the right turns for 220v.

Next....... lets see what she'll do mister :) :) :)

Don't forget to use the ecore ferrite filter... you should do around 25-30 watts for a monster transformer and electronics draw..


......oztules

I could get another turn if you really do think it would help, but as you say 'France' is supposed to be 220vac.

I will check back to you before I fire up the PJ boards on a bench test, and post some Photos of my connections and to what and where, for you look see.

The Secondary connections on the board seem numerous.?

I will look in the PJ 10000w to see how the basic cables go as the boards are the same, but the transformers are series connected.

Several folk have commented on the centre Bolt that holds down the transformer, any particular cautions, when I eventually mount it in my Inverter Cabinet?

Ecore ferrite filter, on the DC + or -  cable ?

Fuseing ? I have this 250a on the DC side, okay? Any more fusing anywhere?
9010-0

Sorry for the simple questions, but all knowledge/help is very gratefully received.
Thanks.

Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

oztules

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The mounting bolt is to be treated as a single very high current turn... in this context, that means nothing may allow a circuit to form between the base/chassis and the top of the bolt/plate. If it does, high current will flow in the bolt and we don't want that.
.
I also use plastic pipe or heat shrink on the length of the bolt so that there can be no interference with the wiring jacket on the primary...... just a useless precaution... but I do it anyway.

The ferrite can be on any of the two wires going to the transformer primary.

The 10kw unit will give you the wiring.... use the fan out of it, as it is "special", and the board will need to see it. The board uses the feedback pulses from it to moderate the rpm... if it can't see that it assumes failure and will shut down when it tries to find it... will run till then.

A normal fan will work if you get a 2k2 resistor and place it on the pulse line to the fan stator, and that will act as a timing pulse, and the PJ will be satisfied. I use beecroft fans as they lend themselves to this modification.

Beware of three wire fans on ebay, some have been found to not have a true tacho circuit on the third wire, and the plugs won't fit either... will need modding.

You only need transformer secondary to board, and board to output point. The other 220v point is for shore power inputs.

The rest of the wiring is just fan and temp probes..... and the 10 wire harness.

Fusing is only to protect wiring, and will not protect the inverter.. 250 amps should be fine, as it won't blow until it sees 500amps or more in the very short term. ( maybe a second or so). Assume wiring is in the > 50mmsq range as well. ( I run 3 x 35mm equal lengths to battery case... one for each string)

I also have a big RCD on the 240v output.... I like leakage detection.....

.................oztules

Flinders Island Australia

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That's a real hardcore project you've done (both master and apprentice)! I payed good money for a commercial version (though mine looks bigger/heavier, though it's 5kW rated).

Anyway, I heard you talking about casting it in resin, to reduce noise/vibrations so I kindly ask you to recommend some good resin to do the job.

I prefer to cast it as a big (flat) cilinder with a inner hole, with minimum wall thickness of 1-2cm all around the transformer.

The problem is I don't want to affect the cooling capacity thus I wonder which specific resin to use (with better thermal transfer).

Thank in advance for any suggestion and sorry for disturbing your great tutorial.   

oztules

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I use west systems.... as I was given 25 liters of the stuff.

We are only using the epoxy for noise and wire stabilization. If you have a commercial torroid, it will likely not have good separation between wires.. these now do.

Just dunking it won't help you unless you can vacuum it at the same time.... and then keep the epoxy as minimal as possible, or you will cause heat build up in the thick epoxy.

I have found that all torroids so far ( commercial) do not take the time to try to separate emf potential in one wire from the next, they aren't soaked in lacquer and cooked.... and so fail regularly from internal shorts.... very sad really.

This technique stops all of those problems from being able to happen... if yours has a larger ( >60 lbs torroid) it is really  a lot better than 5kw at 100% duty cycle ( if the steel is any good and it is a torroid).

..........oztules
Flinders Island Australia

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My commercial transformer was custom made: OD=310mm, ID=120mm, H=110mm, W=39kg (85 lb), 16/125 turns, 30V/230V, high-quality "japan made" silicon steel (according to mfr).

It works OK but I could hear some random noises (vibrations) during normal operation and I thought I could make it dead silent somehow.

Is that west systems epoxy resin thermoconductive/elastic by any chance? I'd like to cast it like a monolithic block but I'm affraid of further cracks due to wire/core thermal expansion or something.

Do you think I could just soak it in lacquer to attenuate those vibrations? Or should I put it between two thick aluminium disks (for better cooling) then squeeze them hard (using some soft rubber sheet in-between)?

clockmanFRA

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Hi lifer,

I used this epoxy, I only used about half,   ........ http://www.ebay.co.uk/itm/370552815307?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT ..which is thinnish viscosity so runs around and in between the wires on each wrap. Takes about 4 hours to get sticky and 12 hours to set. I also used the ordinary tube stuff that is thick for a few jobs sometimes.
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

clockmanFRA

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Ozutules, sorry that centre bolt again.... I have a suitable Stainless steel bolt but its non magnetic, so not sure if that would be okay, ? and not cause problems where it touches the 2 holding discs?

I have a strange black wire coming out of the new 15kW Control Board that's not on the PJ 10000w Board.
9012-0

and on the back of the PCB, I think this wire goes to the battery 48v negative connection?
9013-1

Thanks for the Fan information, I did wonder why 3 wires.
Will I need those 2 heat sensors connecting in, ? they just work the main fan.
The other 2 fans on the PJ 10000w are just heat sensor tripped direct from the 48v battery connections.
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

clockmanFRA

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Okay .. the connections on the PJ 15kW Power Board and control Board.

Is this okay oztules.?

Control Board Connections.

9015-0

Power Board. The heat sinks have threaded holes for fastening your cables.

9016-1

Another question 'oztules', Does it matter which way the Primary is connected onto each part of the Split Heat sink. ?

And there's that mystery wire again.
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

clockmanFRA

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The Fan heat sensors on No2 toroid transformer from the PJ 10000w.

The left larger one is dumb connected to the 48vdc battery connections and just switches the other two fans on.
Hopefully I can borrow the other one and the smaller one.



This heat sensor comes ready attached to the Primary heat sink.

9018-1
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

oztules

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Your connections all look good. The black eye to neg..... I think it solves the over voltage problem, as when I did that, i no longer needed the zener.

The only fan that counts is the primary one., I use a separate circuit to activate my fans, and just have a dumb little fan with tacho wires to satisfy the board, but all cooling is controlled separately for me.

Wire co-ordination is moot unless you want to try the suicide shore power charger..... that required syncing the input to the output..... but if you don't use the charger, then makes no difference that I can ascertain.

For those wanting the charger... I used a 10amp fuse in the line output from the transformer to the board, connect shore power, and the fuse blows or runs fine as a charger.... if it blows, then reconnect the N and L wires from the secondary  back the front and try again.

It does not use cycle by cycle limiting from the secondary for control, so it makes no difference as a stright inverter......, but it does need cycle by cycle control for syncing the shore power to the fet gates for charging usage.

The center bolt can be any material you wish.... but if it is conductive in any way, treat it as a single turn high current winding.... keep it open circuit... ie nothing in the box may touch the top of the bolt/washer, or you will make a connection of the 1 turn.... and gee it will have some serious current attached to that 2v potential....


................oztules
Flinders Island Australia

clockmanFRA

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Again, many thanks 'oztules'.  If you were closer I would buy you a Pint of our local Brew.
Here being advertised by our Cat, Kiwi, (sorry name was a coincidence).
The Family Hubert's just live 8 miles away, good friends........http://www.lesvergersdelamoriniere.com/



Thanks, Black eye to neg... it is, nice to hear that 'PJ' are listening to you.

If I can lift those temp sensors and re-use, I will.  However I will be fitting a temp sensor and switch to switch the other 2 spare fans on, maybe.

No, I will not be using the PJ battery charging facility, but I like your fuse concept for Synchronisation of the HZ with other sources.

Thanks about the centre bolt, it becomes an extra turn if something touches the top......got it.
And yes I have a suitable plastic tube to shield the bolt.

AC Coupling.
 Using used/second hand GTI's, (very very cheap), all SMA as I have Grid guard codes to alter their parameters. These GTI's are taking PV and are connected into the 220vac Mini Grid that the New Inverter is creating, and which the House's, Buildings are using.

Now what I understand from your last comments..... That the new inverter can take backfeed from the GTI's and this can go backwards through the transformer.?
I have done your test with 220vac on the secondary and producing 28vac at the Primary so I see that.

......But this will be AC at 28v. ?
......So its unlikely that the batteries can be charged.?

Battery charging using this Inverter is not required by me as I have plenty of Battery charging sources, 3off 3.7m (12 footers) wind turbines and 5kW Pv on trackers, these are controlled by 3 Tristar Dump/controllers a Tristar MPPT controller and a Midnite Classic 200. The Midnite Classic has 2 aux relay outputs and these can be set to switch on and off depending on the battery voltage. (I love the Classic as its just so good with its charging regime).

I also have a real sweet used/second hand ELTEK 220vac IN, 100a 48vdc, battery charger installed, that can be used if all else fails, ie no SUN and NO WIND.
 In certain conditions this also could be connected to my mini grid and use excess power from the GTI's.  I find that I get a good 10% of PV rated power from my Mono Panels on even gloomy days, ambient light.
Modern GTI's are reasonably efficient so with say 15kW of PV I would still be getting about 1.5kw on those murky days.

Okay raising the HZ frequency to back off/shut down the GTI's is a NO NO, why? because I have a SMA Sunny Island 6kw, actually only rated at 4.2kw continues use.
 And the Frequency Control is very flaky and with me goes up to 60Hz, with not so good consequences. Yes I could get around this, but by totally installing very expensive SMA ancillary equipment, which I will not as this defeats the Self Build/empowerment concept within me. 

Now what I recall you said, "If the GTI's power is not being used, the 220vac voltage from the Inverter increases" or something like that.

Do you recall how much the voltage increase is before things start to get 'hairy' and what increase do you think is SAFE, (without damage) that this Inverter PJ boards can take?
As I can set the GTI's to shut down at say 245vac or whatever.

Now my 5off GTI's are/can be up to 500 feet away from each other and my main Power station Building, so I promised the Mrs that "I shalt not dig any more Trenches",  Sigh, so no way of getting signal cables to the GTI's.
 
 So I will also need some sort of simple PowerLine control to shut down the GTI's when power is not required, but I will separately post on this forum about that.

Yet again, a big thanks to 'oztules'.

I am awaiting some more 50mm/2 flex cable for final hook up, so a few days before I switch the baby on.
 
 
« Last Edit: August 01, 2015, 03:36:58 AM by clockmanFRA »
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

oztules

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..... yes the batteries will charge up to their 60v or more from the grid tie..... not 28v... I 've had many kilowatts going in via that avenue.

The AC will rise when the batteries get full, and no longer create a low impedance to the line input.... if the house load is insufficient to burn it up, then the grid tie will try to push the AC voltage up...... how far????.. as far as the upper voltage is set for the GTI.

250v is fine for a 240v system, and in fact 10% ( 22 or 24v)  is fine really for almost any appliance you can think of.

For a 220v system, 240v is probably the upper very safe limit... maybe 245v.

Yes.... this means remote control of the GTI's is possible using voltage not frequency.... which we cant change anyway. If you have the control codes, then simply set them a volt or two apart, and stagger the release... this way you can drop them off sequentially.... sounds like a plan. My aero sharp GTI's do this as they are programmed slightly differently, so one drops out before the other by only less than .5v difference at about 250v or so from memory. I also have a relay built in the inverter to shut down the GTI from battery voltage.... it is not used anymore.... but there if I want to use it.

All good fun....



................oztules



Flinders Island Australia

clockmanFRA

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That's 'the icing on the top of the Cake'.  :)

..... "yes the batteries will charge up to their 60v or more from the grid tie..... not 28v... I 've had many kilowatts going in via that avenue.

The AC will rise when the batteries get full, and no longer create a low impedance to the line input.... if the house load is insufficient to burn it up, then the grid tie will try to push the AC voltage up...... how far????.. as far as the upper voltage is set for the GTI"
.


Sorry a bit dim at this end........just to Clarify........

So our New Oz Inverter and PJ boards will handle the GTI's and any spare power will infact at first go through the transformer and PJ boards and charge the batteries. ?

Then as the Batteries fill up, or are fullish, the AC 220v Grid that our New OZ Inverter is creating will raise the AC voltage on the said New Mini Grid?

If the above is correct, then ........... My head contents will need updating to understand how AC will push DC batteries, or are you fitting a rectifier somewhere. ?

Yes, I can set all the GTI's to sequential shut down as  the voltage rises and bam! they shut down fast. Starting up again takes about 20 to 30 seconds or so, but meantime the New Inverter can cope short term yes?

If I happen to have say 10kw of PV on GTI's kicking in and feeding the buildings, because of high power use, have you any idea/rough ballpark figure,  how much GTI power the New Inverter can take being back fed and for brief time period so the PJ boards survive, perhaps max 15kw. ?

If need be I can limit the installs of GTI's on this New Inverter accordingly.

 I will check with the GTI's software to see what voltage shut down I can come down to, as you say 240vac should be seen as Max voltage rise.

What does the PJ boards normally put out, exact 220vac or does it wander a little depending on load.?

Yippee, a Plan is coming together..........


Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

oztules

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The inverter will handle significant power in the reverse feed.... wish I knew how much, but 8kw should be in the can do part, and higher for shorter periods. Remember they claim 250 amps in charge mode... so maybe 12 seconds at 12kw???

You will need to keep the GTI's back feed around and below a C10 charge for your batteries.... The PJ has no idea this is happening so will not regulate charge

The H bridge switching mos fets will synchronously switch the DC back through to the batteries from the AC from the grid ties... in the same way it switched the DC to quasi AC. ( @ >20khz or more )

This rectification is very much more efficient than diodes, as the silicon band gap is not there so you don't loose over .6v in the diode before you start...., instead the fets look like a short circuit at 3.7milliohms/6... or  .6 milliohms... so current x  .0006 gives the voltage losses... and so  .06v x 100 amps or 6w per 5kw in the bridge arms.... very impressive... then some switching losses, but still seems pretty good in this format. ( or I^2 x R  is 10000 x . 0006 = 6w per 5kw for 100 amps)

Looking at the scope wave forms, it seems to switch 80% on in 50ns... so losses are not too bad really.

"So our New Oz Inverter and PJ boards will handle the GTI's and any spare power will infact at first go through the transformer and PJ boards and charge the batteries. ?"...... yes........ any power not dissipated in house loads will revert to the batteries.

"
Then as the Batteries fill up, or are fullish, the AC 220v Grid that our New OZ Inverter is creating will raise the AC voltage on the said New Mini Grid?"
... yes as there is no battery load, the AC will rise, as in a normal GTI to grid format. A concentration of GTI's in a street on a single pole transformer will push up the local grid voltage if the sun is out and the systems all run. This will give it a higher "gradient" to run back to the power station/general grid.... ie more power has to go somewhere else or the same place faster.

As a general observation, if you have 15kw coming in, and the loads don't match, the voltage will move to compensate.. setting the GTI's will give you a bang bang regulator. More and smaller GTI's will give better definition I suspect. The wiring to each house in the minigrid will also have voltage differentials locally.. this may help too.... it will depend on the wire size , run length and GTI power. Maybe 1.5kw per house will be enough to be more than useful.

"What does the PJ boards normally put out, exact 220vac or does it wander a little depending on load.? "

It wanders around the set voltage by maybe 5 volts generally very close to 240v for me. Our regs require 3 minutes of clean power before the GTI reconnects... the SMA probably do what ever they please ;D


................oztules
« Last Edit: August 01, 2015, 09:00:40 AM by oztules »
Flinders Island Australia

clockmanFRA

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"The H bridge switching mos fets will synchronously switch the DC back through to the batteries from the AC from the grid ties... in the same way it switched the DC to quasi AC. ( @ >20khz or more )

This rectification is very much more efficient than diodes, as the silicon band gap is not there so you don't loose over .6v in the diode before you start...., instead the fets look like a short circuit at 3.7milliohms/6... or  .6 milliohms... so current x  .0006 gives the voltage losses... and so  .06v x 100 amps or 6w per 5kw in the bridge arms.... very impressive... then some switching losses, but still seems pretty good in this format. ( or I^2 x R  is 10000 x . 0006 = 6w per 5kw for 100 amps)

Looking at the scope wave forms, it seems to switch 80% on in 50ns... so losses are not too bad really"
.


Many thanks oztules for the excellent explanation, and yes it makes sense. I do not think I will ever really get my head totally around 'The H bridge switching mos fets synchronously switching the DC back through to the batteries', but I now understand the principal, many thanks.

Yes I will need to monitor the C10 charge rate of the Inverter when backfeeding, might need to think on that.

8kW back feed, okay, will keep that in mind.

At present I have used/second hand, 2off 3kW, a 2.5kW, a 3.8kW and a 1.2kW SMA SB GTI's. All are not very old and 2 are new, but very cheap as Chips as the small size is not what the FIT, feed in Tariff brigade want for their Roof Registered all above board Installations.

I have just the one SB 3000w working at present on my, rattily, shaky & flaky SI6 Inverter, Mini Grid AC Coupling system.
As you can see, this GTI is set for Island mode, and I can alter the SB3000 GTI Grid setting voltages............
Although NOT SURE which ones yet......?

9020-0

9021-1

And this one has the voltage settings that the GTI will follow......

9022-2


It wanders around the set voltage by maybe 5 volts generally very close to 240v for me. Our regs require 3 minutes of clean power before the GTI reconnects... the SMA probably do what ever they please

I have brought the re-connect time down to about 45 seconds on mine, got fed up of waiting.

Okay we will have to set a max allowable perhaps 235v? and decrease the other GTI's s in 1 volt steps. but I will monitor the voltage at each GTI installation/building and see what voltage drops etc,  and adjust each accordingly.

Just locked up on this summer barmy evening, and I will now have a cool long beer and raise a toast, "TO Oztules and Thanks".



 
« Last Edit: August 01, 2015, 02:31:39 PM by clockmanFRA »
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

Neil

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 clockmanFRA, how's the inverter working?

Neil

clockmanFRA

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Hi Neil,

I have been working at this end on other things. Mostly shoring up some ones house locally with Props, because the twit removed some serious amounts of a brick structural wall, and I have been very carefully trying to remedy the problems.  ::)

However, at last the extra 50mm/2 flexible cable arrived yesterday for the toroid connection to the PJ Power Board.
 The eyelets are now soldered on so shouldn't be long until it gets bench tested/switched on down at the 'Power Station building' where the batteries live, and where I can connect into my Mini Grid and suitably load the New inverter, with the other Inverter switched off of course.
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

clockmanFRA

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Just a couple of photo's of the Toroid  all connected up with the cables ready to go.....

Joints are soldered, cleaned and then Glue Lined Heat shrink wrapped.

I have used 50mm/2 Tri rated/flexible battery cable for the wires from the Primary to the Power board so the board is not under strain.
And 10mm/2 Tri rated/flexible for the Secondary to the Power Board.



Yes, that Choke was tight and I had to just slightly round the inside sharp edges with a fine file, so the cable would slide in and not nip. Again the cable is nice and flexible so little strain on the choke.

9033-1

Note, the 50mm/2 Primary cable ends need to be held together for testing/moving around. Once the Toroid is installed in its case and bolted down, I will clip those 2 cable ties and move the Choke coil away to a better final position.
Everything is possible, just give me time.

OzInverter man. Normandy France.

3off Hugh P's 3.7m Wind T's (9 years).  .. 5kW PV on 3 Trackers, (5 yrs) .. 9kW PV AC coupled Used/SH GTI's, on my OzInverter created Grid, and back charging with AC Coupling to the OzInverter to my 48v 1300ah batteries.

oztules

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Nice work Clockman.
Dont forget to use some super glue or similar to glue the e cores together, or the noise from them can be chilling.... once gled, no noise at all.

I never considered to use the three flying leads from the 50mmsq to the heat sinks... I use single lug to center hole.... but i like the idea.

i still marvel at how much power gets transferred by just those few big windings... just seems a bit magical when 6 or 7 kw is being driven through them, and it all just works..so quietly and without fuss.....still amazes me even though it is only working as it theoretically should.

 I await with interest what you have for us next.


.........oztules
Flinders Island Australia

dgd

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Have stripped the two toroid transformers from my 1500 watt inspiresolar inverters
But what a mess, the face of each where it sat in the bottom of the box had a black papery type gasket that has been siliconed to attach it. Then all placed on a rubber gasket. The rubber one came off easy but the paper one would not. Worse is that silicone glue holding it has seeped in below the plastic tape over the copper wire.
Image shows where I have been slowly picking it away but it seems a lot of the tape will be destroyed in the process.

At the other face the core seems to have been made by pouring in a liquid material that when hardened has been drilled through for the bolt hole. This has also got below some of the winding wire and tape so that several wires seem to be surrounded by the hardened core material.

Looks like a slow process to unpick al of this  >:(

dgd
« Last Edit: August 16, 2015, 08:41:50 PM by dgd »
Off grid since 4/2000
Midnite C150,C250,Clipper, 2.8Kw PV, 2Kw turbine,1025Ah24v FLA (1999), SW3024E (1997), 3q16 48v300Ah LiFeYPO4 6Kw OzInverter, Arduino DUE web monitor.

oztules

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Support it properly, get a big drift, and a BIG hammer, and just knock it out .

The wire will flex as it passes, and mysteriously be fine........ the mylar will suffer minor damage, but there is plenty of spare mylar in there from two transformers to make one.

It should take only a few seconds to remove the core. In amongst all the pages I have written in various threads, there ar pictures of those transfromers before and after the big bang. I no longer try to remove them any other way... waste of time.

If you miss somehow and damage anything, you will have plenty of spare wire and mylar anyway when you combine two into one transfromer, as you save a quarter of the wire and mylar because of joining the two together.

I throw out the first layer of mylar... because of the adulteration as you have found.

Like this:



...............oztules
« Last Edit: August 17, 2015, 04:29:20 AM by oztules »
Flinders Island Australia

dnix71

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Is there some way to add one or two of these coils inline with the battery to improve the startup capacity of a high-frequency inverter? The use of big coils looks like a neat hack, but I have inverters that I don't want to cut apart. I've added boost caps with good results but wonder if adding a coil to store energy in a magnetic field would help with hard start loads or otherwise improve the overall power factor.

oztules

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No.

The weakness of the HF inverter is the energy storage as far as sheer start up grunt is concerned..... and this is controlled by the joules stored at the HV section, and how fast the 12v (?) inverter section can replenish it. Coils in  series with the battery will just act as a resistor.

More capacitors at the HV stage will help with surge, but only if the output fets can handle it.... then it is up to the inverter stage to keep the power up to that stage after that surge.

If the H bridge has a cycle by cycle limiter... your shot anyway.

LF inverters use the battery as the storage facility, but need a decent tight transfromer to be able to translate that to raw surge power.... ie we can think of the battery as a virtually unlimited voltage/current source, and then it is the fets and transformer that are the weak links... so we make them bigger and we are good to go.

I use the torroids as they have very little voltage sag compared to EI types... and half the weight for the same power... less leakage.

..............oztules
« Last Edit: August 20, 2015, 01:05:03 AM by oztules »
Flinders Island Australia