Talk:Solar micro-inverter

Companies

There is not a list of companies that produces these micro-inverters, as Enecsys [1]. --Hamiltha (talk) 13:21, 20 July 2010 (UTC)

Agreed, a list is required, another is Direct Grid Technologies [www.directgrid.com] —Preceding unsigned comment added by 96.56.10.122 (talk) 20:33, 23 July 2010 (UTC)

Agreed and its becoming consensual, it is informative to know all the manufacturers specially if they are few like in this case, in an organized clear way (a list), a list of companies existed previously but it has been removed over the wrong concept that lists are directories this is not correct... and countless articles have list of companies, namely PV manufactures that have one page just for that due to the huge amount that exist. In fact wikipedia teaches how to do lists. A directory is another thing and people should check that wiki definition before undoing lists.

If there are no objections I will add a list of companies — Preceding unsigned comment added by Labbratt (talk • contribs) 06:20, 3 August 2011 (UTC)

Discussion

Where are these used? Is this for some cottage with one panel on the roof or do you put 1.3 million of them together on one site for grid-connected power? If they are meant to be used in large arrays, why are the losses for running 600 V DC around considered worse than the losses for 240 V AC run the same distance? Is there a publication out there that analyzes the economic and technical tradeoffs, and that shows how you decide between a "string" inverter and a "micro" inverter? Is this a topic for its own article or should it be discussed in the "solar inverter" article as a paragraph or two there? It seems the issues affecting microinverters also affect string inverters, and it would probably strengthen both articles if they were compared and contrasted in one place. Do we need the promotional history of the various companies here? --Wtshymanski (talk) 14:45, 24 March 2011 (UTC)

The article does go into the use and sizing issue to some degree. The basic issue is that microinverters cost more than string inverters. For small systems this might mean only tens or hundreds of dollars difference in total system cost. In that case the advantages of the microinverter approach make sense, especially as small systems are more greatly effected by shading (one panel of 10 vs one panel of 1.3 million). For large systems, the increased cost may be on the order of hundreds of thousands of dollars, so any economic losses can be made up simply by installing more panels. There is no hard and fast rule, pricing on all of this is changing as I write this.

As to the "promotional history" I don't know what to say. The fact that Company A invented the first Something isn't "promotional", unless you feel that an article mentioning Bell while discussing the telephone is promotional (IMHO). Rest assured I work for none of these companies, nor any of the (literally) thousands of other technologies I've written about. Maury Markowitz (talk) 21:23, 24 March 2011 (UTC)

I agree with you both, describing history of the products and the companies that contributed to it, is not promotional, but having a range of a company's products can be considered as such and against the wiki principles, if people want to see company A or B's current range of products they can click on a link of the company in a list of manufacturers, a revision of the history section getting down to only the essential, is necessary. Labbratt (talk) 07:03, 3 August 2011 (UTC)

I've made some modifications, see if that helps. Maury Markowitz (talk) 21:41, 24 March 2011 (UTC)

It helps me a little - I had this nightmare vision of 1.3 million pocket inverters wired together like the mother of all Christmas displays in reverse. (These things must be only a little more complicated than the cigarette-lighter to 120 VAC adapters that are now so cheap.) It helps to emphasize that these are most likely used in tiny, isolated plants where your alternative is flying in gas or diesel, as opposed to grid-connected large plants; economics is out the window for cottage power plants anyway, they aren't trying to make an ROI from the feed-in tarriff money.

But this makes the "losses" advantage even harder to understand; an array of 10 panels isn't going to have long enough wires at any voltage to cause significant loss. And even the cottage owner is going to want to know if spending the extra money will give him more hours of TV and lights of an evening. --Wtshymanski (talk) 21:58, 24 March 2011 (UTC)

Ok so some progress! Let's see if we can spruce up the rest. Consider two solar arrays, one is 10 panels and the other 100. We place identical telephone poles on the south side of each array. The shadow of the pole slowly moves across the panels as the earth turns during the day. A mid-sized shadow like this one will kill the output of a panel, so in the 10 panel case we lose 10% of our power, but only 1% in the large array. In the small case you might have just lost all your profit. In the large case, you just had the same effect as washing one of the panels. That's the main issue. There are others, but they are less serious. One of them is the fact that panels used to vary as much as 5% from the same production line, but this has greatly reduced over the last 5 years. DC losses are also an issue, but this is minimized on a small array anyway. In some installations you have the panels facing different directions, and in that case you need multiple inverters for sure (think of it as a permanent shadow). There are also lots of minor practical advantages. Designing strings is a black art that goes away with micros. There's no HVDC anywhere. Parallel vs. serial wiring. Etc. Ok, that's the basics, but it's long and chatty. What do we want to take out of this? Maury Markowitz (talk) 18:58, 25 March 2011 (UTC)

This has got to be a specialized market, then - realistically you'd cut down the pole (or move the panels), and the biggest shadows you get are from clouds anyway. The curious reader, like myself, will want to know how one justifies 10 x 100 watt pocket inverters vs 1 x 1000 watt inverter costing, oh, let's speculate - 75% of the total cost? ( Checking the Canadian Tire catalog for 12 volt inverters, a 1000 watt Xantrex sells for $300 and a 75 watt cigarette lighter plugin sells for $30 - to make 1000 watts with the cigarette lighter plugins takes $400. 75% looks like a good scaling factor. Solar inverters must at least double these costs; the cigarette lighter units are despicably flimsy. ) Can you make more energy (money!) from an array with microinverters? Instead of insulating wires carrying a couple hundred volts DC, you have to insulate wires carrying 120 or 240 V AC - not apprecibly different, needs the same amount of tape to insulate. It would help if we explained why stringing solar panels in series is thought to be difficult; we've been stacking things in series since the days of Volta's pile, what's the key problem in series connections of solar PV? The panels themselves have multiple strings of cells in series anyway. I guess I still don't understand why the sacred Economies of Scale don't rule here. What do you gain for the extra $100 spent on inverters? --Wtshymanski (talk) 19:58, 25 March 2011 (UTC)

Ok, using your numbers (which are accurate) and the fact that microinverters cost about $200 a pop, then a 10-panel system would cost a total of $2000 to wire with microinverters, while the string inverter would be $1500.

Then the question is whether the combination of (shading|module mismatch|uneven weathering|snow pack|different install locations) will result in losses more than $500 over the lifetime of the system, say 15 years. Every kW of panels (about four) will produce 1150 kWh of power a year, or about $925 at the Ontario residential rate. So the 10-panel system we're talking about is 2.2 kW, making about $2000 a year. So we need to recover $500 / 15 = $33 a year. 33 / 2000 = 1.6%. So if those effects add up to 1.6% of the yearly production, which is easy then you're better off with microinverters.

How easy? Trivially. "Realistically" a residential customer can't do anything about *any* obstructions, like the hydro pole or even nearby trees. If you have even the slightest of any of these effects, you go with microinverters. And I am, I'm the 12-panel array on this list. I have a hydro pole directly next to my array, and a tree beside it. There's also some Rogers cables that cast a shadow from across the alley in the afternoon. These add up to about 5%. I am far better off using microinverters.

The problem here is distilling this into a form suitable for the article. Maury Markowitz (talk) 13:50, 26 March 2011 (UTC)

You also asked about why series stringing is an issue. I think the article does a very good job explaining this already. Read it again and let me know if anything is unclear. Maury Markowitz (talk) 13:54, 26 March 2011 (UTC)

The energy of a shadowed panel is gone in either case - this appears to be saying that a shadowed panel affects a series string disproportionately, for reasons that I must study the article more closely to understand. Economics are a secondary factor anyway - you're not spending $10000 on panels to make $100 worth of electricity a year, not when you can put that $10,000 into Hydro bonds and get 4.65%/year. --Wtshymanski (talk) 17:40, 26 March 2011 (UTC)

If the answer to the first sentence is not clear in the article, let me know. It is vital to the microinverter argument. Maury Markowitz (talk) 14:13, 28 March 2011 (UTC)

Shadowing effect needs a diagram. I'm looking at a couple of references now, and the diagram and worked example makes it very clear why shadowing is a bad thing. It's not so clear why integrating a bypass diode isn't a more common solution, espcially as a shaded cell can melt down. I hate drawing charts for Wikipedia, but I'll see if I can get a plot out of Open Office into some acceptable Wiki form (though the image cops will likely hate whatever format I can get out of OO). --Wtshymanski (talk) 21:47, 28 March 2011 (UTC)

Independent references needed

Could we get some references that don't come from manufacturers of inverters? --Wtshymanski (talk) 22:04, 27 March 2011 (UTC)

How do they work?

How do the inverters stay in step? What happens if they go out of synch? If there's no transformer inside, how do they step up from ca. 40 volts at the panel to sqrt(2) * 240 volts? (Is the output even sinusoidal, or stepped (modified square wave), or square wave?). How are they connected in parallel? Does each one have a fuse, or does the melting of some overworked switching transistor shut down the whole array? Never mind calculated MTBF, how many years warranty do the manufacturers offer? ( That figure is set by cold-eyed accountants, not wildly optimistic sales people). Looking at the manufacturer Web site doesn't answer many of these questions. --Wtshymanski (talk) 14:58, 28 March 2011 (UTC)

The answer to the first question is the same as any inverter. The main inverter article could cover this, if it doesn't already. The rest of the questions are fairly specific to each company. I can answer them here but I don't think they should go in the article.

Most modern DC->AC systems use switching power supplies. Some use transformers, some don't. Enphase does, BTW. Enphase's warrantee is 15 years, I've seen 20 and 25 from other companies. Enphase has a breaker, but it's sealed inside the case from what I can see. The parallel stringing is in the wire, which in most new designs is external to the case. Maury Markowitz (talk) 21:20, 9 May 2011 (UTC)

No brand names

Could we get rid of all the brand names unless there's something unique and valuable (to the encyclopedia) in listing a brand? The first product (referenced) or the current best-selling product (referenced) might be notable, but a catalog of inverter suppliers is not notable. --Wtshymanski (talk) 04:10, 27 October 2011 (UTC)

Manufactures are useful information I for one would like to know that there is more then one company making them, specially being a "new" tech, many wikipedia pages have this, for example there is a list of the main manufacturers of PV panels, as discussed previously, with no contest, we should have a list with manufacturers with actual products installed that can be verifiable in some way. Prototypes and announced products probably should not be listed as the added information value is limited.

Furthermore the current major vendor/competition maybe ok for some but it doesnt seem right to me, i see this in no other credible article, just seems like advertisement, not even fair one at that. following this road will just lead to what we are seeing, the competitor companies not being very happy about it, with good reasons and wanting to add their own product specific advantages and achievements and all out wiki war. so we should end this. enphase should have its contributions rightly recognized briefly in the micro-inverter history and an entry in the list of companies with reference projects. From there we can move on from this brand war and on to some science.Labbratt (talk) 06:56, 31 October 2011 (UTC)

I'd love to see this "science" you speak of. As it is, there is exactly one miv in commercial use in north america, and one in europe. Both were mentioned in the article. One of those has over a million installations, the other doesn't. No one else comes remotely close. That is why Enphase received the lion's share of the History, because they developed the lion's share of the history. I am considering a complete revert unless you can offer a really strong argument to the contrary. Maury Markowitz (talk) 01:28, 6 March 2012 (UTC)

I'm shopping for, and educating myself on, PV technologies. This is one page among many I've referenced. Three points: (1) A list of active global manufacturers of Solar micro-inverter solutions in the Wikipedia category Solar_micro-inverter is about as notable as it gets ("notability guidelines do not apply to article or list content"), (2) the Wikipedia WP:NOTDIRECTORY sec 1-7 does not advise or even infer against manufacturer listings (if you disagree, please cite specifics from Wikipedia WP:NOTDIRECTORY section), (3) though not its primary role, Wikipedia is used as a consumer tool by millions. A convenient alphabetical listing of manufacturers is a common Wikipedia feature and is both helpful and educational. I disagree with prior comments that (1) mfr's listing is not valuable, (2) listing of mfr's is not notable, (3) listing a brand-name is "advertisement", (4) plays favorites because some companies do not know how to add their name to a Wiki page, (5) violates Wiki guidelines. I have reverted the article back to included manufacturer's listing as I believe this is clearly within the guidelines of Wikipedia and the expectations of its users. Audio77 (talk) 16:39, 4 November 2012 (UTC)

Where is the listing of manufacturers? I came to Wikipedia looking for just that, to update information I checked a year or so ago. It is indeed a needed part of this page. Leaving it out comprises a bias toward Enphase keeping the lions share of the market; an advertisement assuming that there are no other serious contenders in the marketplace. Home Power magazine recognizes at least 2 other manufactures selling units here in the US. Can anyone provide such a listing to me if the editors here think I shouldn't have that information? PaulKrumm (talk) 03:29, 6 January 2013 (UTC)PaulKrumm 5 January 2013

Voltage in Europe

In Europe we now use 230 Volt; according to IEC 60038. In GB it is 240 V, 50 Hz. — Preceding unsigned comment added by Ha pe11 (talk • contribs) 19:29, 13 July 2012 (UTC)

The United Kingdom (including Great Britain) has standardized on 230 volts as well, with a tolerance range that includes 240 volts. Residential solar grid-tie systems in the United States also work at 240 volt AC output. Alan Larson (talk) 16:46, 26 May 2013 (UTC)

Implications of Mean Time Between Failure ("MTBF") claims

Regarding MTBF quotations of millions of hours, this does not imply that these designs are capable of operating more than a few years. An MTBF estimation is taken within the context of the wear out time of the device. In hot climates, the life expectancy of micro inverters is severely limited by necessary energy storage components termed electrolytic capacitors. While longer life capacitors are available, they either lack the required energy storage capability, or are cost prohibitive. Large inverters, particularly those that operate with three phase electrical systems, have advantages life wise. — Preceding unsigned comment added by 65.160.229.33 (talk) 16:44, 16 April 2013 (UTC)

Need to remove or rewrite and relocate references to cascaded multilevel

This text is poorly written, and unrelated to the rest of the paragraph/section:

Furthermore,Various modulation strategies have been introduced for the cascaded multilevel inverters to reduce the harmonic contents [8]. Of all the topologies Cascaded has many advantages than diode clamped and capacitor clamped inverter [9][10]. A further study on cascaded multilevel inverters was performed to highlight the advantage of cascaded multilevel inverter and the switching patterns are analysed [11]. as a single model can be used with a wide variety of panels, new panels can be added to an array at any time, and do not have to have the same rating as existing panels.

It looks like it needs to be removed until it can be rewritten as its own section. That section will need to explain what "cascaded multilevel inverters" are. Errors in grammar make the segment unreadable.

I would recommend removing it until someone can figure out what it is saying to potentially rewrite it. — Preceding unsigned comment added by Alan Larson (talk • contribs) 14:28, 8 August 2014 (UTC)

Micro Inverters

Based on what I have read on the micro inverter wiki I may not be able to continue to use wiki as a source of information as I have been doing research on micro inverters for a couple years now and I read on the title line of the micro inverter that it is superior to a string inverter. This is not a verified fact I have been integrating solar systems for 3 years and have had nothing but headaches from these devices and if you read any community forum on micro inverters you will find the same.

I am really disappointed in wiki for publishing this. I was searching for how a micro inverter was made to freshen up on facts and I found this.

So sad :( I really relied on wiki for so many things. — Preceding unsigned comment added by 68.110.4.3 (talk) 13:52, 25 October 2014 (UTC)

I read on the title line of the micro inverter that it is superior to a string inverter. You did? Where? Maury Markowitz (talk) 21:48, 6 February 2015 (UTC)

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GOOD JOB ON THE LEDE!

I know I'm not supposed to do this, but I'm going to anyways. The Article would "be improved" if you leave the lede completely alone. I came here with some basic noob questions about solar microinverters and the lede answered all of them immediately. It's perfect. Don't "fix" it.68.206.249.124 (talk) 15:11, 31 October 2020 (UTC)

Consider to review the prices in this article

In several instances prices and price / watt is mentioned in the article. While usefull, as it is one of the considerations when choosing a type of inverter, it seems that many of these prices are outdated. I'm not an expert, but I suspect that prices (Per watt) have lowered considerably in the mean time. Maybe it is a good idea to remove any mention of concrete pricing at as many places in the article as possible, in order to make it more future proof. Yvolution (talk) 16:00, 28 January 2021 (UTC)