Converting square wave inverter to sine wave

Hey guys, saw this on net

http://www.circuitsdiy.com/convert-square-wave-inverters-to-sine-wave-inverter/

Need comments of you guyz.... @Ijaz Ahmed @aurangzebhaque

[quote=“nasirjavaid, post:, topic:”]

Hey guys, saw this on net

http://www.circuitsdiy.com/convert-square-wave-inverters-to-sine-wave-inverter/

Need comments of you guyz.... @Ijaz Ahmed @aurangzebhaque

[/quote]

My electronics knowledge is almost zero but according to my general information Sine wave circuits are much more complex than square wave and modified square wave circuits therefore they are costly to produce ........

The link you have provided doesn't make much sence it can't be that simple .......

[quote=“jamalkhan, post:2, topic:21774”]

My electronics knowledge is almost zero but according to my general information Sine wave circuits are much more complex than square wave and modified square wave circuits therefore they are costly to produce ........

The link you have provided doesn't make much sence it can't be that easy .......

[/quote]

yip I know sine wave circuits are very complex but this says converting square wave to sine wave.... but still its backed up by some knowledge.

check it out, it does create sinewaves but don't know how practical it is in inverters.

http://www.edaboard.com/thread286524.html

What you need is filters.. filters that filter.. thats what they do.. thats what is needed.

getting the right filter to match your frequency input is a big big task.. you would need very expensive filters and also accurately matched and many of them too. the technology behind them is all that matters.

this is what seperates Schnieder electric from hall road kits..

[quote=“farhan_ds, post:4, topic:21774”]

all you need is filters.. filters that filter.. thats what they do.. thats what is needed.

[/quote]

Farhan,

The ALL is misplaced. In theory it seems easy that you need to attach filters at the output, and get sine waves. However capacitor and inductor based filters are not easy to implement. Secondly practical filters can be implemented when the load is constant. Variable loads such as those faced by a UPS would need variable capacitors and inductors that are almost impossible to make.

Therefore sine wave output is done at the circuit level in Sine-wave inverters rather than adding filters to square wave outputs. Usually a mixture of both techniques is used in the design of the inverter where the circuit generates a waveform close to a sine wave and a small and cost effective filter cleans up the waveform bringing it closer to a sine wave.

I would not suggest anyone to consider venturing in adding filters to try to get sine wave o/p from their square wave inverters. The sizes of the capacitors and inductors are difficult to achieve locally, not to mention the dangerously high/lethal voltages that can develop in these filters if the load is not properly matched to the filter.

Aurangzeb

http://chaokhun.kmitl.ac.th/~kswichit/didik/sineinverter.pdf

The above link takes you to an experimental inverter designed for generating sinewave albeit at 5 watt power output level.

Aurangzeb

@aurangzeb.. you are right, i should have better placed the ALL word..

however i wrote the same thing that input point of electrical source would require a matching kit to produce a frequency that has to match the filters at the end.

1 - kit and circuit with matching frequency production of sinewave .

2 - filters to clean out the rest of the output..

there are high capacity and quality filters available which will probably clean about 90% of a square wave.. those heavy duty filters are used at smal factory levels with dedicated power production for self sustaining levels minimum, and each cost more than a new APC ups alone..they are used because replacing aging old power generation equipment with bad efficiency at wave production which is requird for modern machinery would get a cost effective benefit from replacing filters only instead of investing in a huge industry level power generation plant alltgethr.. even enterprise level filters are way way costly..such filters are specificall made on order and are industrial grade mostly.

home use filters are smaller and work only practically when matched with a good inverter, with a quality modified sine wave..

square waves are not much help able. a large capacitor will improve its wave form , but is prone to patakha, requires very high cooling, not suitable in our summers..however since medium filters or capacitors are affordable and they can modify a hazardous square wave to even a 50% improved wave, its still a benefit instead of buyng a new ups.. not a good solution, just a small tootka to get better slightly more acceptable results.. :)

PS: apparently that is what i am seeing in our locally made desi ups wrapped in big preety boxes and led displays giving them an imported look and writing sine wave on boxes everywhere.. just a capacitor on output wire. .. they get excelent reviews from people since when they blow up along with fuse, they are very easy to replace at cheap, and our population is happy on very low buzzing ups noise and quality after sales service :)

@nasir javed..

the exprimenal approach is for lab esting only as in the links you provided.. for real practical use, you would need atleast 2x the power required in your home with variable sized capactors to match your constant output like aurangzeb has explained nicely.. so the cost will automaitically double than the one projected in links per your power requirements

hmmm.. very nicely explained by you bros farhan and aurangzeb... so i think better option is to use the sinewave kits available in market whch I saw on my visit to hall road. they were available for 2700Rs. But i think they are in early stage yet and need lot of improvements.

a decent 900W APC ups now days is cheap enough to be easily affordable. full sinewave and excellent battery life and zero restarts.. also very small in size and portable with full front panel diagnostics.

Yip APC is best. Our company had 10KVA APC UPS installed at data center and it was running hell lot of load of servers and stuff. As I remember it has serial port connection with pc for adjusting settings and status display too.

Any idea of price and good location to purchase from? as it is altered to use wet battery and increase charging current and not all do it well so finding good one is difficult. Secondly as delicate electronics, there are less shops and engineers which car repair when it goes bad.

Use pm for details..

most times nothing goes wrong with it ever..even if it does.,its now very easily repairable.

please pm share any details if you have regarding it. thanks.

by the way chit chat is going on with your ups guy :)... and how about course... I want to get enrolled :)

please pm any detail you have in this regard, I may switch to APC and m conscious regarding burning of my tv, laptop charger, modem and fan dimmer etc...

by the way what you think about this for learning ups

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Pure Win..!!!!! :D

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