Custom Inverter

So, after havingwatchedJulian's latest mail bag, I decided to check out "Alice" on eBay, and see what they have available.

I came across this nifty piece of gadgetry (~$5):
http://www.ebay.com/itm/DC-AC-Pure-...794356?hash=item48881616f4:g:qNsAAOSw9GhYgvM7

I was looking over the datasheet and I'm wondering how hard it would be to actually make an inverter, or a UPS, for our powerwalls. Afterall, most of everything else is custom made; and inverters are expensive!!! We could even use an old MOT that is rewound to get the transformers needed.


Here's the datasheet:
http://www.lz2gl.com/data/power-inverter-3kw/eg8010_datasheet_en.pdf

So, based off the url (didn't notice it in the datasheet as I didn't read everything, just skimmed), this thing can handle up to 3kw. Correct? Can someone verify this?

The IR2110 FET driver is only a few bucks. As well as the LM393 Dual Voltage Comparator. Those are the 3 main IC's in the inverter/ups build. The only other major expense would be the transformer.

Could it be possible to add in an arduino controller to monitor everything and make this a super smart inverter/ups that gives us loads of information; including efficiency on-the-fly both charge/discharge?

Elmo loves the smell of magic smoke in the morning, it smells like learning.

I've let the magic smoke out of two brushless water pumps in less than a week, same mistake both times, a constant current power supply doesn't mean constant voltage when you remove the main load. That thing would probably burn like Arthur Brown if I looked at it sideways.

Three kW! The meltdown would be visible from space..

LOL!!! Well, I was figuring it was just the controller board that told the other stuff what to do and when. The mosfets would be doing all the heavy lifting, along with the transformer(s). Still learning the circuits aspect of things RELEASE THE SMOKE!!!

The funny thing is that an MPPT controller is a good bit simpler conceptually and electronically than a three phase brushless motor controller, if I buy from China I can get 1kW brushless controllers good to ~50V for about $25 each before shipping.

I suspect the difference is in the toroidal inductors, the three phase controllers don't have those and big ones for high power are expensive. I've been trying to come up with a cheap substitute for a long time and have never really made any progress.

The folks on the wind energy forums have gone so far as to pull the ferrite dust out of sand with magnets and make coil forms for generators with a epoxy/ferrite dust mix. Cheap yeah but more than a little labor intensive.

Wow this looks like fun. I have 2 3K UPS's sitting here looking like this:

[img=400x297]https://lh3.googleusercontent.com/p...22EBEMqyoKjM9rHyMvTkRevaU=w1240-h920-no[/img]

Maybe I could just build one and not fiddle with all the twiddily bits in this thing. It looks like it has most if not all the parts I would need...
Now I just need to know how to hook it all up! This could get real interesting...
I am going to order a few of those.
I wonder if there is a 220V module?

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I just ordered 4 of them...
I found the manual for the board:http://www.egmicro.com/download/EGS002_manual_en.pdf
Take a look here for EGmicro's other Inverter Products:http://www.egmicro.com/products/inv_tran.php

Google does a decent job a translating the pages, but the diagrams are not. I am not an electronics guy, but I guess I'm gonna be...

Magic Smoke here we come!

Can you guys tell what the input voltage for these can be? It look like the datasheet specs up to 400V?Also would like to get it to 220V output, the diagram on the datasheetlooks like 220V out.

Oh man this is gonna get crazy... Probably should test with some lower voltages first!

Let's keep this rolling.

Rudy

Thanks Rudy. At those prices, we can afford a little magic smoke. Im really curious about this project and where it goes.

Rudy, ur pic didnt show up

Korishan said:

Thanks Rudy. At those prices, we can afford a little magic smoke. Im really curious about this project and where it goes.

Rudy, ur pic didnt show up

Click to expand...

Ahh, still getting the hang of this....
Fixed now!
Rudy

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It looks like the computation side and the High Voltage side are optically isolated. I built a crappy MPPT charger based off of Julians MuPPeT experiement, and this use the opto isolators. I burnt a few of those up with some voltage issues. I never got the programming right as I blew it up with 24V and did not make the time to figure it out. I think the Inductor was a little too big, and some of the components topped out at 23V like the arduino voltage sensors. I may pick it back up after I get the 7210Aboost converter up and running with a battery bank.

You can see how I tried the MPPT charge controllerhere in this pic:

[img=400x142]https://lh3.googleusercontent.com/h...T4pMHrUZ2GSu__7nHJ169iK50=w1920-h685-no[/img]

It's messy, but it was a prototype. I smoked at least 3 transistors and 2 opto-isolators.

I have no Idea how I am going to fabricate an inverter. I can hook wires together and solder some, maybe even design a board with one of those softwares. Electrical theory and all that, nope, not very good at it, so I will be looking for this to be a group thing as much as we can.

@Korishan thanks for the original post, I cant wait to get started. All you people with EE degrees, I will take any and all input.

Rudy

Glad your taking on the task, Rudy. I currently dont have the time, and im lacking in the electrical field. However i am learning.
Knowledge is power, literally in our field

that sounds quite like that video
as a guy working in the IT i have several customers using apc upss, maybe i really should get some proffessional education regards electronics

basicly, any ups is sort of what we want as an inverter, question is, can we mod it to charge or atleast take the voltages we have? i think i will ask some people if one has an 3k ups lying dead or something like it, most people dont want to change the batteries, but thats not my fault^^ on a plus side - most newer apc upss have quite decent webpages with infos regards the draw, volatges and such

for more text to read https://www.eevblog.com/forum/proje...an-apc-ups-into-a-powerful-sinewave-inverter/ sort of competition?

MajStealth said:

that sounds quite like that video

as a guy working in the IT i have several customers using apc upss, maybe i really should get some proffessional education regards electronics

basically, any ups is sort of what we want as an inverter, question is, can we mod it to charge or atleast take the voltages we have? i think i will ask some people if one has an 3k ups lying dead or something like it, most people dont want to change the batteries, but thats not my fault^^ on a plus side - most newer apc upss have quite decent webpages with infos regards the draw, volatges and such

for more text to read https://www.eevblog.com/forum/proje...an-apc-ups-into-a-powerful-sinewave-inverter/ sort of competition?

Click to expand...

I also work in IT, Cyber Security for over 20 yearsso I have seen a ton of this stuff. I have 6 Datacenter UPS batteries I can charge to along with the 2 'small' 3000W UPS's

Yeah that is where I got the Idea a while back. I got a 48V DC to 110 AC model SUA3000XL.
I had read quite a bit a while back and the more I look at it, I think just scavenging the components off of it to do the work may be the easiest method. I have 2 of them. if I blow it up, meh, I will just get a real one.

The control modules are on the way, so I will need to figure out the design of the High Voltage side. The company that made the modules had some schematics.

I just got some of my Amazon Shipment in, I will be updating my build thread in a bit.

Rudy

i am lucky i am just the guy that fixes all kind of stuff, printers, beamers, displays mostly everything that is in some sort of trouble and worth to put some in to bring it back to live

cyber security - anything without a network cable and without any way of accessing it without unscrewing a sidepanel is safe - i would say^^ everything else its just time x until it gets fucked up big time, time is 1/10 if it is a woman or a guy that has no woman - i think you know why^^

Yeah, I saw knurlgnar24's video a long while back. That's also where i got the idea for re-purposing an old ups for an inverter. I have an older style stand alone unit that is 3kw as well. I would of liked to have gotten a rack style unit; but you get what you get when you can get it

Hopefully this will turn out to be an interesting thread using these parts. At some point, maybe even split it off to it's own thread once some of the basic stuff is outta the way/figured out.

anyone with some deeper insights into electrics here? what would happen if i power 2 or more inverters from the same batterypack feeding the same ac-circuit? i could think of nasty things happening with shifted 50hz (germany) invertion - most likely a new "half life" game would apear

Nice topic. I thinking of the same. I already had a 300W toroidal power supply for leds. Two of these should give me a really good base for an 24V inverter or I can rewind it for 48V.
Hmm someone tested this EG8010 sine-wave generator on an another forum and it's not totally sinus, but for starter it's enough. I should get some power fet too and I'm ready to facing the smoke monster

MajStealth said:

anyone with some deeper insights into electrics here? what would happen if i power 2 or more inverters from the same batterypack feeding the same ac-circuit? i could think of nasty things happening with shifted 50hz (germany) invertion - most likely a new "half life" game would apear

Click to expand...

It's not a easy process, but if these inverters have a build in sync option you can do it easily. Otherwise you need some EE skills and some tools like scope, clamp meter etc.

Note the big inductors, those transformers have a lot of inductance in there. Heavy metal still costs, there's a lot of copper and silicon steel in those two big ugly lumps.

The first step would be to power it up and put a scope on the waveforms under various loads from light to full right at the drive for the transformer(s), that's where the action is. If you can "record" those waveforms and then recreate them with your own circuitry and software/firmware that's the basis for making them work under custom control.

They expect the power circuitry to develop significant heat, lots of fan power focused on the driver and the transformers.

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From a strictly hardware point of view I think trying to use transformers like that UPS has in a DIY inverter is a bit of a dead end technologically, it's doable but once the supply of that particular model runs out you have to design it all over again.

I think moving to toroidal inductors and using a switching frequency above human audio range, say 60khz to synthesize the AC waveform directly is a more technologically fruitful way of going. A great many things are easy now that used to so, so difficult.

Take Julian Ilett's MPPT controller and extend the concept to cover generating AC with the same inductor at the same time. It's a fairly trivial amount more hardware, the complexity is going to be in driving it, the software. Once you have say a 50 watt version working scaling it up would involve some issues but at least you would have an idea what's happening.

There is no point in supporting daytime loads on your solar with two devices when one will do the trick, keep the inefficiencies to a minimum.

MajStealth said:

anyone with some deeper insights into electrics here? what would happen if i power 2 or more inverters from the same batterypack feeding the same ac-circuit? i could think of nasty things happening with shifted 50hz (germany) invertion - most likely a new "half life" game would apear

Click to expand...

This can be done, but can be tricky. There are a few ways this can, and can not, be done. If you have 2 dumb UPS's, then it is not advisable. However, the first step "could" work with those, as well.

Common)
a)They both can charge the same pack, as the two together would only increase amperage to the packs.
b)They can draw from the same pack, as the two together will draw double the amperage from the packs (make sure the wiring is adequate for that heavy of a draw)

Dumb and Semi-Smart UPS's
1) Connect the "slave" UPS to the "master" UPS via the power cable from the "slave" to the output outlet of the "master"(doesn't really matter which is which; however, probably the higher rated one would be master if they are different)
2) Connect the "master" UPS to mains via power cable
3) Power on the first UPS and wait for it to fully initialize
4) Power on the second UPS and wait for it to fully initialize
5) Unplug/Disconnect the "slave" UPS from the "master" UPS
6) Unplug/Disconnect the "master" UPS from the mains power

*NOTE: You can probably/possibly connect the "slave" to the "non-backup" receptacleon the back of the "master" and when the master is disconnected from mains, that receptacle will also be powered off. Be cautious of this and make sure that this actually is happening before attempting to do this method.

Now both UPS's will be in full inverter mode and both inverters are synced to each other producing the same wave form of mains.

Smart UPS's
1) Connect "slave" to the "master" via communication cable; or, if smart enough, set one to be slave through settings
2) Power on "master" and "slave" and wait for fully initialized
3) Unplug/Disconnect from mains

Now as they sit, they are not in split phase mode. They are still both sitting in single phase. There has to be a little trickery involved to get split phase.

I do not condone or take any responsibility for the next steps. Any damage done to devices or mains, etc, is not my fault, problem, or responsibility. Do this at YOUR own risk

To make the split phase, you would connect the Neutral leg to the Hot leg between the two UPS's. Usually you'd connect the Neutral from the "master" to the Hot of the "slave". Then you have this following setup:

Hot --- Neutral --- Hot

This will allow you to connect 1 Hot to one phase, and the other Hot to the other phase.
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The last setup I am just going off memory from knarlnar24's video's. You can verify by going through his video list and checking the wiring of hooking up two UPS's in series. I think he may even has a video on connecting them in parallel. There are steps that need to be followed, and followed correctly and exactly, for these things to work correctly and as expected.

High voltage is a highly respected thing to deal with. Treat it as such. Especially for those of you who have 220/240 as a single phase hot (whereas in the US, we have 220/240 split phase, 110/120 per phase.

Proceed with caution. Knowledge is Power! Literally!

If you replaced the AC input, noise filter and bridge rectifier with a solar panel and cut this to only two phases you have the basis for an inverter. Your MPPT and voltage boost would take place at Q1 and the AC generation in T1 - T4.

Thinking about that circuit more since I'm awake at 4 AM, what you want to do is generate a full wave rectified AC waveform (which is pulsating DC) across the capacitor with the inductor/transistor combination and then unrectify (invert) it with T1 through T4.



The way you would generate that waveform is by varying the switching times of the transistor controlling the inductor under microprocessor control. At zero crossing points (the sharp bottoms on the graph above) you switch from one pair of inversion transistors to the other, basically that's just a fast DPDT switch or relay.

The Devil of course is as always in the details, the higher your switching frequency the lower and hence cheaper values you need for the inductor and capacitor but other issues show up with increasing frequency, you need fast high power, high voltage switches to keep switching losses down and they become more costly and so on..

Wow this is waaaaayyyy more complicated than I had figured.... I thought it would be close to that MPPT buck charger I built.

I found the post where this module was used earlier:http://www.gohz.com/homemade-2000w-power-inverter-with-circuit-diagrams

This seems like a boost converter that somehow creates a sine wave.

So let's keep this as simple as possible.

@elmo you seem like the EE here I think we will need some expertise in how to build one to run off this chip.
I found this interesting paper on building one:https://web.wpi.edu/Pubs/E-project/Available/E-project-042507-092653/unrestricted/MQP_D_1_2.pdf

I wish they were less expensive, I would just buy one.

Rudy

My experience with things like this is that the basic circuit starts out fairly simple but the complexity expands with protection mechanisms; over current, over voltage, short circuit, over temperature, etc.. etc.. Each extra protection mechanism adds another layer of parts and the system moves toward overall incomprehensibility without serious study.

It seems to me a lot of the functionality should be wrapped up in software/firmware as opposed to hardware, hardware is difficult, time consuming and expensive to change, software for the most part is none of that.