Grid Tie Inverter Schematic

[Thunderchild]

I didn't see any grid tie inverter schematic there. Just a lot of talk and a "partial" H-bridge with no drive and even then, it wouldn't work without about 50 times more circuitry ! OK, maybe only 45 times more parts.

I do see a picture of something that is supposed to be an inverter, (and maybe an IGBT nodule)

Do we see a picture of a wind turbine, a solar panel ? I didn't see that either.

It would have been a lot more interresting to get a complete hand writting shematic than spending all this time putting long answer to this tread.

Otherwise, this might be called "Guerrilla Wind".

tcmtech, to prove me that I am completely wrong could you send me your grid tie shematic ?

Thanks a lot

I concure !!!

 

[tcmtech]

Not a problem!
ONE home made wind generator.
ONE home made GTI With actual gages showing the input amps and volts coming from the home made generator on a windy day.
ONE complete home made GTI system with watt meter.
AND one complete schematic of the power handling circuit.



And My standard offer to all of the doubters that I have ever came across.

JUST STOP BY MY PLACE AND HAVE A LOOK FOR YOURSELF! I HAVE NOTHING TO HIDE. BRING ANY METERS AND MEASURING EQUIPMENT YOU WANT TOO! I WILL EVEN LET YOU TAKE MY STUFF APART AND STUDY IT AND TAKE PICTURES AND VIDEO TOO!

And it your really serious, bring the sheriff and a lawyer too! I will even take bets on the workability of my designs!
(I just want the sheriff and lawyer present for when you are actually required to pay up on the bet!)

If your serious, just pm me and we can discus where I live and when your coming.
Although like every doubter I have ever met I already know you wont show!

I've played this baiting game far to many times already to get fooled by it!
If you thinking of guerrillas I can assure you there are no monkeys here!
But I am seeing some poo flinger's!

I just passed you the ball! You wanna play or what?

 

[Thunderchild]

3 photos 1 showing a probably damaged ampmeter by now and yet another incomplete schematic showing no references to other schematics.

and more self important talk, look you started out saying you were going to show people how to do it then said you were producing a CD with all the info to sell on ebay then produced some snippets of schematic..... do you really have the time for this ? please if anyone has actually suucessfully build a GTI from information on this thread please do come forward.

if you think I'm flying over from the UK just to admire your work yes then you win of course the odds are hugely in your favour.

you may well have accomplished what you say but after saying you wanted to help everyone build one "oh sage teacher" you fed dribs and drabs of inconclusinve information and a few half hearted schematics that are hardly rerlated to each other.

bottom line: get a life

 

[be80be]

Wounder how they did it before uC fired up one generator went to plant two and when
in sink close the line. Simple. If you use a step down transformer to to get your power cycles you almost have what you need to step up your low voltage to mains almost. You have a nice 12, 24,48 volts at 60hz in the US even a sine wave lol. Just use that switch your bridge taking your low voltage to mains. Don't take a lot of parts would work power company may not let you but.They show you how it's done in

Transmission and Distribution by Central Station Engineers of the Westinghouse Electric Corporation book was printed September 1, 1950

 

[tcmtech]

you started out saying you were going to show people how to do it then said you were producing a CD with all the info to sell on ebay then produced some snippets of schematic..... do you really have the time for this ? please if anyone has actually successfully build a GTI from information on this thread please do come forward.

I would also like more help on this subjet too! There have been a few one posters saying they would supply information but they have yet to provide. Right now I am the only one that is continualy trying to supply any solid info.

So what do you do with your time? Who do you work for? How much free time do you have?
Some days you come across as a unemployed jerk or as someone with a grudge against people that do have jobs they like! Or you just dont like me! ( I can sleep well at night knowing that.) I just dont know!

I own a small but successful and growing business. How about you? Do you know what having your own business can take time wise? Do you?
My line of work is very erratic and seasonal. I dont have 40 hour work weeks year round. Sometimes I have 0 hour work weeks and others times I have 100 hour work weeks!
Since the snow melted I have been picking up more work so I am not able to put much time into this. Most of the time I am here on this forum is while I am doing information searches relating to work I am doing or planning on doing.

And in several previous posts I have clearly stated that this is a sideline project. It is purely a "just because I want too" project.
I have also stated several times in previous posts that I may very well not have my CD done until far later than estimated. Maybe the end of summer and maybe not until next year. So I work on it as I very well please.

Given your continual negative posts about the whole subject why would you care when I get it done anyway?

Regardless of my personal attitude, it should be fairly obvious by now that I am willing to share my knowledge with the world! But on my terms!

Today is Sunday, plus I am rained out. So I have time to work on these threads.

I agree that I may very well come off as cocky about this subject, but I feel I can back it up! I have very little evidence of you posting much of anything that has much learning value on any subject on this whole forum. Just my opinion.

I am starting to think you may either be very closed minded or very jealous of what others can understand and or do!
Taking shots at other posters that do have the time, willingness and means to donate information is very low and cowardly in my personal opinion.

All of what I have produced so far is completely free and open to the public end user to modify and manipulate to any extent they want!
No one has to believe in or follow my ideas or information if they dont want to!

I do not hide or Deny that this information I am providing is very word based. I also do not hide that I have purposely made these descriptions rather generalized either. I want people to read, think, and learn. I know it sucks, but some times you have to think for yourself!

If you want something bad enough you either have to work for it or pay for it!

By reading all of the posts I have thus far written, a good reader with a fair electronics background could easily work out the conceptual design of my most complex system I have. But still they would have to actually do the follow up work themselves to put all of the pieces together! I write these long posts for a reason. Clues!

Given the overall numbers related to the views of these two GTI threads and the time frame those numbers have been generated in, I would say someone is taking this available information with some serious interest!

But this is just all my personal opinion. If I wanted to stoop to your level I could just print " If you think Thunderchilds attitude is unreasonable or unwelcome in this forum, leave negative feedback reguarding him!"
But I wont, because I am not like that!

 

[Thunderchild]

when your CD is out i may buy it if reasonably priced using money i earn by working ! bearing in mind though that in the UK I can't use such a unit anyhow and I find it a little disturbing that in the states anyone can connect any plile of junk they have made to the grid. perhaps its that I think people should not be building these things in the first place you have no idea of how knowlegeable and patient people are, you really think that everyone that read this thread and is thinking of building a GTI will actually be able to put all your scattered info together and build a reliable unit ?

apparantly you have these upand running yet you just said that you also need more info on the subject.

 

[Thunderchild]

Regardless of my personal attitude, it should be fairly obvious by now that I am willing to share my knowledge with the world! But on my terms!

on such a potentially dangerous peice of equipment either your comming clean with all you have or your not, your just inspiring people to make attemps based on your clues, I'm not a health and safety maniac but i do beleive in basic comon sense

 

[tcmtech]

on such a potentially dangerous peice of equipment either your comming clean with all you have or your not, your just inspiring people to make attemps based on your clues, I'm not a health and safety maniac but i do beleive in basic comon sense

No argument from me on that one! I will side with you on the proper use of common sense (and Safety) everyday of the weak regardless of personal differences!

What a person finds on the INTERNET is public domain information, whether it be complete or not, and how you apply it is your own responsibility!
The originator of said information has no legal or implied responsibility for what someone else does with that information.

What a person does in their own life relating to personal safety and what not is their business not mine!
I cant keep you from taking a bath with your toaster while its plugged in and running, just because you read about it on the INTERNET!

Personal Safety Is just that, Personal. What you do and how you do it is not for me to decide!

And should someone approach me with the intention of wanting to have me do a design or custom build of anything for resale to the general public, I and he will have to meet all required laws, rules, and regulations related to design safety and any other necessary requirements for that product.

 

[Thunderchild]

well just because there is incomplete or incorrect information on the net does not make it any morally better for anyone else to follow suit

 

[altech6983]

Hey guys, I have been following this thread because really we have been looking in to doing wind energy and maybe even solar and we need a grid tie inverter. I have looked up the prices and they are just ridiculous and so me being a electronic hobbyist I decided to see if there are any schematics out there when I came across this post.

@ tcmtech: From what I have read (the whole thread) and understood, it seems to me that you do indeed know what your talking about and I know that you are trying to help people learn while still keeping your design sellable.

I have to say that if you really do know what you are talking about then this would be perfect for me and I while gladly buy your CD (hope you can get it out soon), that is if I haven't figured out how to build one (probably won't as I don't have enough background theory in electronics).

With that being said, I did run across this pdf:

**broken link removed**

I don't know that this will be helpful but it may give somebody a few ideas, and yes I know it isn't a grid tie inverter (at least I don't think it is, I haven't dived in to it, just skimmed it).

Anyway keep up the work on the CD, hope you get it finished soon (and with a reasonable price ;-) )

 

[Val Gretchev]

Grid-Tie Inverter

Making small grid-tie inverters (250 watt) may be fun and educational, but scaling up to something more practical (2kW to 4kW) may prove to be challenging.

In order to minimize wire losses in bringing power from a roof mounted photovoltaic array to ground level or basement where the electronics box is mounted, the PV array is wired in series to generate between 150 and 250 volts. This reduces the current to a reasonable level and allows for smaller gauge wiring to be used. A pre-regulator is then required to boost this voltage to a useable level and keep it steady as the PV voltage fluctuates depending on the amount of sunlight available.

Current designs favour an interleaved PWM boost topology to eliminate a step-up transformer for higher efficiency and lower cost.

One such design, published by Steve Ward, can be used as the front-end of a high-power boost converter. See his web page at: 12kW PFC Boost Converter

Although Steve uses his boost converter for an entirely different purpose, I feel it could be adapted for the application described above. Simply remove the AC input and replace it by DC coming from a PV array. Follow the boost converter with an H-bridge and transformer as per Freescale design clip below.

 

[Existenz_69]

@tcmtech
I think you've been a godsend here and have actually given me hope of completing my 7kw wind turbine setup. As always the GTI was the limiting factor. One question i have though...can your design handle the 850 volts ac (open curcuit voltage) and the 7.2k watts that the generator can produce? I would also assume that i would need a rectifier to bring the 3-phase AC that is generated down to DC. Any help you could provide would be GREATLY appreciated and i'd even be willing to pay for your knowledge! My wife is currently unemployed and they've cut my hours, so we would be able to help do some write-ups or create PDF's for your cd if you wanted. I have web Design experience and I'm also very good at video editing and production. I don't think that i could provide you with any EE help since you're far above me in skill level. Thanks in advance!!!

 

[tcmtech]

Hahaha, Thanks for the vote of confidence!

So how are you getting 850 VDC output? And what are your local utility line voltages?
Tell me more about your system and how you came up with the design!
We all want to know!
Got any pictures?

I dont know everything there is to know by any means and most of what I have given out is just the bottom end basics. I would be happy to help with a custom design!
Would you want to do it independently or would you be interested in starting a new thread related to a big GTI like say 5 -10 kw with much higher input and line voltages?

I think it would be helpful doing most of the layout work here so others can benefit from our work. Plus there are many here with great electrical and electronics back grounds that jump at any chance to catch my mistakes!(and occasionally just help out too)
So far there is this original thread, the 250 watt thread, and my tiny GTI conceptual design. I would like to round off the set with a big multi kilowatt GTI myself.
For a big GTI thread I would be willing to give up the basic schematics for the more advanced H-Bridge control circuits and PLR based monitoring system. The H-Bridge control circuits have proven reliable in longer term real life running conditions on the smaller units but the PLR program is what I am currently still fine tuning for my big test units.
But ultimately I would leave it up to you and the readers to pick out what would be most practical for yours and their applications.

So far the highest experimental GTI H-bridge circuit I have tested is running at around 450 volts peak. But since I do not yet have a wind or solar power source that can supply that at tens of amps I have only done the testing off of a 12 KW gas drive gen set. So I do not have testing numbers from real life long term usage to work with.
I dont see any reason why a 850 volt system couldn't be done practically.
It's basically just changing the H-Bridge and power handling components and and modifying the control system voltage dividers to read those higher values.
There are IGBT's Rated for 1600 to 2500 volts now and at high amp capacities too. Same with the rectifiers and capacitors. So component wise there is no real limitations.

If you would like start a new Thread relating to it. It would give everyone a clean start to work from.
Until the nutters waist a few pages on pointless run around arguments that have been thoroughly discussed and already covered in this and the 250 watt GTI thread. Plus add there usual space wasting rant posts.

 

[chucks]

pls i need someone to help me with dc-ac iverter circuit diagrams of about 500watts to 1500watts,50hz,12v to 240,a modifined sine wave

 

[Val Gretchev]

Here is a conceptual schematic of a grid-tie inverter. The parts shown are large mechanical components that are mounted directly on a heat sink or in the enclosure.

I find it easier to use the CAD system and place a few parts on paper to see how a design shapes up. With a push of the button, I get a BOM which shows me the cost of components and where extra effort will be required to bring those costs down.

In single unit quantities you can see that building a grid-tie inverter is not economical. For a few dollars more, you can buy a commercial unit.

I still haven't figured out how to specify the inductors and the filter components. I would prefer to be able to obtain off-the-shelf manufactured components. If anyone has the knowledge how to calculate these components, please let me know.

 

[tcmtech]

All new parts gets very cost prohibitive very fast!

The listed IGBT's, big heat sinks, 450 volt capacitors, and transformer are all items that I have found on eBay for around 10 - 15% of the list prices according to your BOM sheet. (most were Buy It Now listed too!)

That will save you a pile of money right there!
Does the transformer have to be a toroid? If not a standard commercial isolation transformer will probably be way cheaper and far easier to find surplus or used.

If you dont mind recycling a box from something else or just getting some sheet metal and making one yourself you can get by cheap on the box too.

How much or how little a person spends is inversely proportional to how resourceful and creative they are.
Little resources or creativity spends big. Big resources and creativity spends little.

Do you have more schematics related to the control system?
And more detailed specs relating to the input voltages and operating conditions?

It may be possible to reverse engineer the inductors from what the system is intended to work with power input wise.

I assume they are working as part of a boost converter of some sorts.
Once the amps, volts and switching frequency are known then its not hard to calculate their values.

 

[Val Gretchev]

Re: Grid-Tie Inverter Schematic

I tried to find off-the-shelf components so that I could duplicate the design in any quantity. Substitutions are allowed as long as the general topology is followed. The semiconductors specified are robust enough to handle any power up to 10kW. The magnetics will ultimately determine how much power can be produced. The largest transformer I could find is 1500 watts. I suppose that one could find standard isolation transformers that can handle more power. The best thing, of course, is to get rid of the transformer altogether and rely on the distribution transformer. However, from what I have read, a transformer in the inverter is required in North America but not in Europe. I am not sure this information is correct.

I have a general idea for the signal conditioning electronics but have not inputted the design into CAD. The microcontroller stuff is standard and can take many different forms.

The input voltage is 150 to 250 volts. I read somewhere that the practical limit for a boost converter is around 5 times the input voltage. Splitting the power path into 2 reduces the current requirements for each of the inductors and improves the ripple in the output.

 

[Existenz_69]

@TCM
I started a new thread named "Multi KW Grid-Tie Inverter Build", hopefully we can learn how to do something this powerful and not blow ourselves up!!

In response to your question about 850VAC... You're into wind power right? Well, as you know the wind turbines can easily reach over 600 volts. If you look at ginlong's web site their 5KW generator can reach like 800-850 volts at 260 RPM! (open-voltage). Of course they're $3K. This WAS what i was desiging my system around (until i found out they were $3k!). I've since decided to go to ~3KW but the voltages are still mostly the same. My mains are 120/240 60Hz NA. I'm not 100% sure if Ginlong's generators are 3-phase or not, but i would think so. I do have one question about 3-phase. If we had a generator that was 3-phase, could we just use a 3-phase-to-240VAC converter to put voltage into our mains? Most of the wind turbines i've seen are 3-phase and i was just wondering if we could bypass the 3-phase - rectifier - inverter system with just the 3-phase converter, since you can buy them off the shelf. Also, i have a transformer out of a 1440 VA UPS, would that transformer be good enough for a modest inverter? It weighs about 10 lbs, but i can't find the specs anywhere. Anyways, i'm super interested in learning about the bigger inverter!! Thanks so much!!

 

[tcmtech]

I am not exactly sure about the needing an actual transformer on an American system or not.
I cant find anything in specific related to needing full isolation from the actual power source if the power source itself is not actually electrically connected to the earth ground or if it has full electrical shielding to prevent human contact with any live circuits or wiring in the NEC code book though.

I would think your set up could work with a direct line connection but the main transformer would be replaced with a set of inductors and PF capacitors to help clean up the wave form going back onto the line.

I dont see any reason why a standard isolation or step up or down transformer would not work. I use them on all of my experimental GTI's and have never found a reason not to use them. Their cheap and easy to find. Toroids do have a typically smaller size per VA and slightly better efficiency but I dont think the overall gain can justify the added cost.
I personally use isolation transformers because of the voltage differences on my systems and just to keep the power sources isolated from the main line.
My present wind generator uses a negative earth ground for added static protection.
Fiber glass blades can generate static under some conditions I have been told.

 

[mneary]

If it turned out that isolation between the DC and AC was required, it makes a lot of sense to do it at the boost converter (high frequency) rather than at the line attachment (lots more iron and copper).

Of course that would make the final stage a lot harder to troubleshoot, since they would always be hot with respect to your test equipment.