# how to convert the inverter generated square wave output to sine wave using filter circuit

Discussion in 'General Electronics Chat' started by dhevkumar, Dec 9, 2015.

1. ### dhevkumar Thread Starter New Member

Sep 11, 2015
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0
Hi
i need to integrate the pv with grid, so i used a mathematical modelling of single phase inverter eg input 100v dc i got output as 100v ac(square wave) using triangular pwm technique, i used LCL filter circuit to get sine wave ac output(but iam getting only around 0.2 v ac as sine wave. why the output voltage is too low after filter circuit.
i used LCL(L=2mH, c= 3 microFarad, L=1.3mH)filter.

2. ### Veracohr Well-Known Member

Jan 3, 2011
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What's the frequency?

3. ### #12 Expert

Nov 30, 2010
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We've seen some pretty silly mistakes before. A schematic works wonders at helping us understand the problem. It doesn't have to be good art work, merely accurate about the electronics.

4. ### wayneh Expert

Sep 9, 2010
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A signal good enough for grid tie-in will not be a simple project and will likely be illegal in your jurisdiction. This thread should probably be closed.

5. ### #12 Expert

Nov 30, 2010
16,671
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Do you click the "report" button and tell the Moderators when you believe this?
I believe you should "notify the authorities". They are very good about judging this kind of situation.

6. ### wayneh Expert

Sep 9, 2010
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I usually do, and did exactly that for this one. I'm sure I've overlooked many others. Got my Grinch on today?

7. ### dhevkumar Thread Starter New Member

Sep 11, 2015
21
0
Switching frequency for the triangular pwm - 16k HZ
grid frequency is 50hz

Nov 4, 2013
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9. ### Alec_t AAC Fanatic!

Sep 17, 2013
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Why do you want to tie your inverter to the grid? If it's to get a subsidy on your electric utility bill then the utility is unlikely to accept a home-brew system.

10. ### tcmtech Well-Known Member

Nov 4, 2013
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A lot of people do pirate grid tie co gen simply as a way to lower their electric bill using whatever AE systems they may have at their disposal on their side of the meter.

As far as home brew goes there are many people who have understandings and the skills to be able to design and construct systems that are of equal to superior quality than many of low end off the shelf products that are out there.

11. ### wayneh Expert

Sep 9, 2010
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There are also many people that are blithering idiots.

I thought that, at least in the U.S., it was illegal to attach to the grid anything that might zap a line worker.

12. ### tcmtech Well-Known Member

Nov 4, 2013
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Years ago I has a student co op electricians apprentice job at one of our big coal mines and got first hand training and experience with working with the utility level systems and what safety procedures went into that work before anyone went up to any part of the HV gear or cabling. 4160, 7200 and 23,000 were the line voltages I worked with.

Line workers have a good deal of safety protocols and procedures they have to follow and have in place before they ever work an a power line. Two them are isolating the line section to be worked on on both sides of where the repair work is being done and having both ends solidly grounded on top of that.

If lines can not be shut down they have standard live line procedures to follow before anyone does anything as well.

On top of that it's even less likely that anyone would have their own home built power source synched up to the utility lines that would have enough capacity to hold up the local loads anyway being what typically takes the utility grid down is a short circuit some place and if their multi megawatt per circuit capacity could not hold it up someone's at best multi kilowatt solar/wind power system certainly wont.

Given that I see very little validity in the concerns about trained legally authorized utility workers getting killed due to some one backfeeding. They have procedures and just know better than to grab on to a line that has not been properly secured.

13. ### wayneh Expert

Sep 9, 2010
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I'm sure I'd be equally cautious about touching anything out in the field. But I think the fact remains that doing a DIY grid-tie is illegal. Not sure about the TS's jurisdiction.

14. ### profbuxton Member

Feb 21, 2014
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tcmtech, I would take issue with your comments re "backfeeding" into mains supply from any "homemade" or storebought inverter system. It is highly illegal and dangerous, and I don't care how well "trained" and what procedures are in place it must never be allowed.
Even under the best practice there is a grave risk of line workers being injured or worse.
I am aware of two recent instances of people being injured, one fatally, by "backfeeding".
Admittedly during testing and other works but dead is dead. One worker was working on a 6kv transformer which was "backfed" from the secondary 240v.
And another person was injured as a high voltage bus was being "backfed" by others from a totally separate building.
These were trained people who had, as they thought, taken suitable precautions to make themselves safe.

15. ### tcmtech Well-Known Member

Nov 4, 2013
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People will ultimately do whatever they feel like doing regardless of what others think about it and people will die due to accidents and their own personal negligences to follow procedure every time.

I know it, accept it and have gotten over the urge to push my beliefs on others.

As for the two people you mention all I can say is obviously they did not do proper isolation and shorting and confirmation of each befor going to work on things. Personally I would never work on a HV primary power circuit without having confirmed my self that it was both isolated and in a dead short condition first. Those people obviously didn't and now they paid for it.

I have no control over the safety procedures of others and whether or not they follow them. It's not my job or responsibility to keep others alive. It's my job to keep me alive.

As far as this thread goes someone asked about how to solve a issue with their DIY grid tie system so I passed along what I know. That's all and how they apply their knowledge and actions legally or otherwise from it are not my problem. Never has been and never will be.

16. ### Alec_t AAC Fanatic!

Sep 17, 2013
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It is a concern, however, for the AAC site owners; otherwise the Terms of Service wouldn't ban posts which "encourage unlawful behaviour" .

17. ### tcmtech Well-Known Member

Nov 4, 2013
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Other people's paranoia and lack of ability to rationalize the 'what ifs' of things for what they realistically are plus not understand that there are internet anti liability laws protecting them and us from sue happy idiots that use information illegally to hurt themselves or others is also not my problem.

18. ### profbuxton Member

Feb 21, 2014
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tcmtech,in regard to the incidents I mentioned, it was not the individual doing the work, but another unrelated party who "livened" things up.
However , I find your attitude strange to say the least. So theoretically speaking, you would be happy to leave a loaded firearm laying around and not feel responsible if it was used in a fatality(shooting, suicide etc.)
Electrically speaking, you would also happily give advice to anyone wanting to carry out electrical work and let them wear the risks. I suggest you may find such action would result in a court appearance in many jurisdictions.
That is all!

19. ### tcmtech Well-Known Member

Nov 4, 2013
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What I see is lock out tag out procedures were not put in place thus leading to a tragic accident. Nothing more.

The guy who flipped the switch and killed the other probably didn't know anything about the work let alone why what ever he turned on was turned off. Involuntary manslaughter due to some other persons negligence to properly follow what are now standard safety practices in most every work place that has potentially lethal equipment or conditions. They guy who didn't do a proper lockout tagout or set up other such identifiable means to show that the circuit was off is at fault and that typically is the responsibility of the person or persons who are doing the work and no one else.. Not the guy who flipped the untagged switch.

As far as fatal shooting with firearms and who put the bullets in when and where that is a strawman argument and totally irrelevant to the topics at hand. The person who pulls the trigger is at fault. I've got too many friends who own firearms to not know my basic firearm liability laws.

Last edited: Dec 12, 2015