Author Topic: A Big OzInverter build.  (Read 2858 times)

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clockmanFRA

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A Big OzInverter build.
« on: November 27, 2016, 09:06:14 AM »
     
This may amuse or assist others, and takes me on another voyage of discovery.  Yet again a big Thanks to ‘Oztules’.

See other links here on this forum regards OzInverter builds,  ‘Oztules’ builds, the PCB’s etc, ...  POWER board, OzControl  board, and the double OzCooling board. We can Now make a complete powerful OzInverter without the need of any outside manufacturer.

My 6kW OzInverters are working flawlessly and doing what I wanted, especially with the AC coupling and the AC back charging.   Remember we are shutting down the GTI’s with a slight rise on the AC output voltage from the OzInverter created Mini Grid, when the batteries start to reach full charge.

Some of you may be aware of my total untrust of the HZ increase rise that some Inverter manufacturers use, a very unpleasant  personal experience, (at 54Hz my household synchronous motors, Microwave, washing machine etc will not run correctly).   Especially when you have a mix of renewable energy DC ,(my wind turbines) and AC charging coming in.  (scarily, I read recently that there are moves ahead to make HZ increase a standard amongst all Inverter Manufacturers, talk about manufacturer  lock in!!!!!!).

So this BigOzInverter build will push the boundaries a bit.  I am looking at a constant 8kW to 10kW output with large surges.
 My present battery bank is 48v 1300ah, so most of the time I have GTI’s, (Solar Grid Tie Inverters) putting their power into my OzInverter created Mini Grid. But, there will be times in the future where the BigOzInverter will be required to step in for a few minutes or so.

I talked about my BigOzInverter design here……
http://www.anotherpower.com/board/index.php/topic,1117.0.html?PHPSESSID=h7jd5l4edljl6k4ls18pgfj4i1

The Toroid Build……….

So I have a 38kg core, at 230mm OD, 100mm centre hole and 140mm thick/high.
80 turns of 6 off, 1.8mm diameter secondary and 10 turns of 1 off, 75mm/2 for the primary.

The 38kg (about 83lbs) core is heavy and awkward to lift and turn without damaging the enamelling on the windings. The 1st  photo shows an amended winding table with sufficient space to safely get my fingers under the core and cleanly lift. There are 6 rubber mats cut out, each at 1.1mm thick taped to the table. This works well as the rubber gives and spreads the weight without collapsing or being too stiff.

Differences with Testing the Secondary windings.
My normal 25w 230vac test bulb that I use on the 6kW OzInverters was just too small a wattage for the toroid to step up to full 230vac on each winding, and my workshop 20 amp MCB would trip out.
However, replacing the 25w with a 100w 230vac test bulb works fine, as the interim step for the each secondary taking a full 230vac. But be warned the 100w bulb will not illuminate, the toroid seems to want everything.

These first 2 secondary windings are fine and each gives the same Induced voltage readings.
The 2nd Photo shows the 100w bulb that is now bypassed with that insulated croc clip, so the toroid first secondary winding is taking the full 238vac Mains, and inducing 238vac in the second secondary winding. And Yes, I will tidy up the windings before I resin coat them, but I always test first.

WARNING. Yes,! I should know better!
230vac is serious and will probably KILL you, so be very very careful.    Check and double check.


« Last Edit: November 27, 2016, 01:13:57 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.

clockmanFRA

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Re: A Big OzInverter build.
« Reply #1 on: November 27, 2016, 09:26:28 AM »
Those of you who have followed the OzInverter as it evolves, may find some information missing, especially around our own manufactured PCB's etc., Hopefully I will fill in the missing areas with this BigOzInverter Build.

While I am building the toroid, I am also putting together other important items.

EMI filters....

Ist Photo .... I have been happy with the 40amp 250vac 50Hz, 4off unit arrangement and this works well on the 230vac output from the 6kW OzInverter.

3rd Photo .....  Here is my Block diagram regards the design of the triple unit, 9off, and connection system. for a 60amp on the BigOzInverter.

These individual 20a 250vac 50Hz EMI Filter units are about $7 each, 9off for my big filter unit would be about $63, which is not to bad.
 As 'Oztules' has mentioned "Well that should filter out some noise. Front loader washing machines with older series wound motors need a filter on the output so as to run their spin cycles properly.... and yep, that would do it."

I also found that with this filter my Auto ranging HZ meter was a lot more stable when reading the final OzInverter output.

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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Re: A Big OzInverter build.
« Reply #2 on: November 27, 2016, 12:59:15 PM »
The shunt shown is for the 6kW OzInverter, obviously for my big one this will need to be bigger.

dgd, not sure how we can get the shunt rating up so it suits the Mega. I heard a rumour that Father Christmas might bring me a Tablet.....
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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Re: A Big OzInverter build.
« Reply #3 on: December 10, 2016, 01:52:58 PM »
The Fundemetals of the Toroid build.

I have been asked, so I am backtracking a little bit.

Firstly……
"We want the primary to be about 30 to 32v for the PJ style processors, and 28-30 for the 8010 chips for a nominal 48v system."

Next……….  Defining the Core or stacked Cores you are using.  Another ‘Oztules ‘ empirical working calculation…….
So I have a 38kg/83lbs core, at 230mm/9inch OD, 100mm/4inch centre hole and 140mm/5 1/2inch thick/high.
 
 "Lemme see...... I make that as about 9100mmsq cross section... so ... and here I can only go rule of thumb....9000/2800=3.25
So I figure about 3.25 volts per turn. So the secondary will be about 73 turns, and the primary will be about 9 turns.
How that would be worked out mathematically I can only postulate, but the in the real world measurements I have done, it would seem to indicate that roughly 2800mmsq of cross section at 50hz will yield about 1turn/volt.... so 9000mmsq would be about 3.25 volts/turn.

If we wind for a few more volts than we want, our saturation is further away... so say 240 or 260v for a 220v system gives us leeway and lower magnetising current ... from there about 1:8 primary : secondary…. and we have a workable start point.... at least that how I would tackle it. ..... ' Oztules '"

Other considerations should be noted regards the core material. My core supplier company reckons that to much varnish getting into the 0.3mm thick 3% silicone Iron alloy laminations, has a considerable magnetic degradation of 15% with varnish, and 40% with epoxy.

So using my experiences with the 6kW Ozinverter .... the BigOzInverter is 80 turns of 6 off, 1.8mm diameter secondary and 10 turns of 1 off, 75mm/2 for the primary, basically the magic 8 to 1 ratio.
I am looking for a test 28v - 30v on the Primary when I put 230vac on the secondary,  our boards are the 8010 chip processor.

Pics…… shows the BigOzInverter toroid test,  just using a 2.5mm2 test primary wire. ………… 234vac going in the secondary’s after the step up light bulb process, ……… and  29.4vac reading on the Primary.  So we are in the right ballpark.
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.

gsw999

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Re: A Big OzInverter build.
« Reply #4 on: December 11, 2016, 02:25:46 PM »
I dont understand this but it looks good !!

clockmanFRA

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Re: A Big OzInverter build.
« Reply #5 on: December 17, 2016, 02:30:20 AM »
Hi gsw999,

I am not a electrical/electronics engineer, and what has been written about the 'OzInverter' on this forum and others is very comprehensive, but can be incomprehensible to most normal folk.

So what I am trying to do here is fill in the gaps so to speak, with the complete build and the New up-to-date PCBs that we also make.

I love pictures, as just that one Pic has all sorts of other information in the background.
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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Re: A Big OzInverter build.
« Reply #6 on: December 17, 2016, 02:54:52 AM »
This is the 6th and final 80 turns of 1.8mm diameter secondary.

Each of the six secondary's is epoxy painted/coated. Here in this pic its just a light coating so the copper wires are locked to themselves and the 5th secondary Mylar wrapping.
Light coating of epoxy prevents movement and eventually failure of the copper wire.

Mylar wrapping..... The bare cores get 60 or 80 grit flap wheel on the sharp metal edges. Then 3 wraps, with each wrap getting 1/3rd overlap, the secondary's get 2 wraps with also a 1/3rd overlap.

Its always a gentle battle to get the secondary's through the centre hole in a tidy fashion. So the primary cable can also go in tidily, although its not desperately important as long as the primary correct turns all go through that centre hole, and there is space in the middle for the mounting holding down bolt stud.

Note... those coils bottom left are from my 12footer/3.7m wind turbines, that I wound a few years ago, they were rejects, (over or underweight) from the 36 I required. The copper is 1.8mm diameter and not to badly deformed so its re-used.

« Last Edit: December 17, 2016, 03:26:34 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.

clockmanFRA

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Re: A Big OzInverter build.
« Reply #7 on: December 17, 2016, 03:16:57 AM »
The Ferrite core.......

On one of the two Primary cables from the Toroid.

Brings the idle power loss right down, from about 150watts for a 6kW to about 35watts. It does this, as I understand, it by filtering the Primary cable which has about 20kHZ running through it.

See first Pic......... 6Kw OzInverter with Ferrite .....


My Primary cable for this BigOzInverter is 70mm/2, But on the ferrite core I am using a short piece of very flexible welding cable at 18mm/ 3/4inch diameter, wrapped around the 20mm x 40mm x 56mm long centre section of the ferrite core. 3 complete turns is ideal/optimal, 4 is a little better but it seems that it is not worth the extra hassle involved.

Here I am using 2off these cores stuck together with super glue or resin…… .. http://www.ebay.co.uk/itm/370683164776?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT http://www.ebay.co.uk/itm/370683164776?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

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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Re: A Big OzInverter build.
« Reply #8 on: January 30, 2017, 12:14:46 PM »
Just a little update for those of you that have been concerned about our reliance on the Micro chip 8010 that controls our OzInverters.

'Frackers' mentioned sometime ago that this 8010 chip has spare k for a bit of coding, but 'Peter' ......

http://www.anotherpower.com/board/index.php/topic,1228.0.html?PHPSESSID=h7jd5l4edljl6k4ls18pgfj4i1
 
"using the ATMega328" has seriously pushed the boundaries and is getting some very impressive results.

Real nice to see that the OzInverter no longer needs any particular manufactures specialist control chip, so get your ATMega328's out.   
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.

joestue

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Re: A Big OzInverter build.
« Reply #9 on: January 30, 2017, 05:51:04 PM »
It would be interesting if you could program it to drop the frequency upon overload.

Once the frequency drops below 55Hz significant power should be available from any other induction motor running off of it, at least for a very short time, which might let you double the "line start" capacity of your inverter if you have other motors running.


anyhow, clockman do you have a gap set for that ferrite core? if there is no gap, once it saturates with a substantial load its benefit is gone.

clockmanFRA

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Re: A Big OzInverter build.
« Reply #10 on: January 31, 2017, 12:12:01 PM »

anyhow, clockman do you have a gap set for that ferrite core? if there is no gap, once it saturates with a substantial load its benefit is gone.

Hi joestue,
The Original reason for the ferrite choke was to get the idle power use down. My original APC UPS 5000va was using about 200watts.

'Oztules' found that with the ferrite choke on the Primary cable, just glued together, then a 6kW OzInverter was only using about 35watts when just ticking over. As far as I am aware, its something to do with a filtering process with the 20kHZ.

The TOY  Inverter I purchased from a well known German company, and sent back, seemed to use different toroid windings in it for achieving low wattage standby use.

 
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.