http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

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250 to 5000 watts PWM DC/AC 220V Power Inverterby nickk on April 7, 2009

Table of Contents

250 to 5000 watts PWM DC/AC 220V Power Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Intro:   250 to 5000 watts PWM DC/AC 220V Power Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

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http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

Intro:  250 to 5000 watts PWM DC/AC 220V Power InverterThis is a heavy duty design of a Pulse Width Modulator DC/AC inverter using the chip SG3524 .I've been using it as a backup to power up all my house when outages occur since aprox. 6 years non stop.

If you like the work and intend to build the circuit don't forget to click on the "follow" button so I know how many people benefit from the design, Thanks.

Notes:

1> The schematic circuit design is for a 250 watt output, while the pics are of my 1500 watts inverter that i built, to increase the power of the circuit you have to add moreof the Q7 and Q8 transistors in parallel, each pair you add will increase your power by 250 watts, ex: to get 750 watts of power from the inverter you need to add inparallel 2 of Q7 and 2 of Q8 to the original design.

2> If you increase the power transistors you have to enlarge the T2 transformer to match the new needs, the circuit's transformer is rated 25 amps to handle 250 watts of220v, for every 1 additional amp you need on the 220v side you have to increase 10 amps on the 12v side, of course there are limits to the thickness of the winding so ifyou need more than 750 watts i recommend that you use a 24VDC supply instead of 12 volts:

DC voltage and Transformer "T2" winding recommendation:Power SupplyWinding750w 12VDC P:24V "12-0-12" / S:220V1500w 24VDC P:48V "24-0-24" / S:220V2250w 36VDC P:72V "36-0-36" / S:220V3000w 48VDC P:96V "48-0-48" / S:220V3750w 60VDC P:120V "60-0-60" / S:220V4500w 72VDC P:144V "72-0-72" / S:220V5250w 84VDC P:168V "84-0-84" / S:220V* The transformer should be "center tapped" at the primary side.** You can make the secondary 110v if needed.*** The transformer in the pic is a custom made (48V center tapped / 220v ) 2000 watts, weights like 10 kilos.

3> R1 is to set the PWM duty cycle to 220v. Connect voltmeter to the output of your inverter and vary VR1 till the voltage reads 220V.

4> R2 is to set the frequency to 50 or 60 Hz (R2 range is between 40Hz to 75Hz), so guys that do not have a frequency meter are advised to blindly put this variableresistor mid-way which should drop you in the range of 50~60 Hz.If you want you can substitue the variable resistor with a fixed resistor using the following formula: F = 1.3 / (RxC)in our case to get a 50Hz output we remove both the 100K and the variable 100K both from pin 6 and we put instead a 260K fixed resistor and we leave the 0.1uF (the104 cap) as it is, this change should give out a fixed 50Hz as per the formula :1.3 / (260,000 ohm x 0.0000001 farad) = 50HzBut in reality it will not exactly give 50Hz because the 260K resistor has a specific error value margin so does the capacitor, that's why i recommend a variable resistor sothat accurate calibration can be achieved.

5> Use either tantalum or polyester film "as in pic" for the 104 caps, ceramic disc caps change value once hot and this in turn changes the frequency of the inverter sothey are not recommended.

6> Pin 10 of the SG3524 can be used to auto shut down the inverter, once a positive voltage is given instead of negative to pin10, the SG3524 will stop oscillating. Thisis useful for persons wanting to add some cosmetic makeup to their inverters like overload cutoff, low battery cutoff or overheating cutoff.

7> Wiring connections on the power stage side should be thick enough to handle the huge amps drain from the batteries. I marked them with dark black on the schemaalso I included a pic so you see how thick those wires must be.

8> The design does not include a battery charger since each person will be building a custom version of the inverter with specific power needs. If you are ordering acustom made transformer you can ask them to take out for you an additional output wire on the primary side to give 14v (between point 0 and this new wire) and use it tocharge a 12v battery, of course this needs a seperate circuit to control charging auto cut-off. But anyway this is not advisable because it will shorten the life of thetransformer itself since using it as a charger will toast the enamel coating layer of the copper wires over time. Anyway .. YES can be done to reduce cost.

9> A cooling fan will be needed to reduce heat off the heat sinks and transformer, i recommend getting a 220v fan and connecting it to the output T2 transformer, whenyou power up the circuit the fan will start this will always give you a simple way to know that 220v is present and everything is OK.. You can use a computer's old powersupply fan if you like.Note that the fan must suck air out from the inverter case and NOT blow inside, so install it the correct way or it will be useless.Also note how I fixed both the heat sinks and where the fan is, in a way that the fan sucks hot air from like a channel between the 2 heatsinks.

10> 2 circuit breakers are recommended instead of fuses, one on the DC side and one on the AC side, depending on your designEx: for a 24vDC ( 1500 watts design ) put a 60Amp breaker on the DC side and a 6Amp on the AC side.For every 1amp of 220vAC you will be draining like 8 to 10 Amps from the 12v battery, make your calculations !

11> The 2 Heat sinks should be big enough to cool the transistors, they are separate and should NOT touch each other. "see the pics"

12> Important: If you're building a big design that uses more than 24VDC as power source, make sure not to supply the driver circuit with more than 24v maximum.(EX: If you have 4 batteries 4x12 = 48v , connect the v+ supply of the driver circuit to the second battery's (+) terminal with a thin 1 mm wire which is more than enough.this supplies the driver circuit with +24v while supplies the power transformer with +48v) "see the batteries pic example"

13> "Optional" : Deep Cycle batteries are your best choice, consider them for best results .. read more

14> Be cautious when building this circuit it involves high voltage which is lethal, any part you touch when the circuit is ON could give you a nasty painful jolt, speciallythe heat-sinks, never touch them when the circuit is on to see if the transistors are hot !! I ate it several times :)

15> The optional "Low voltage warning" is already embedded in the PCB layout, you can disregard it and not install it's components if you do not need it. It does notaffect the functionality of the main circuit.

16> The Motorola 2N6277 is a durable heavy duty power transistor, it is used in many US tanks for it's reliability but unfortunately it is a very hard to find part, insteadyou can substitute each 2N6277 with 2 x 2N3773 or any equivalent.

17> I've included an optional "Battery level indicator" circuit diagram that has 4 LEDs, you can see it installed on the front panel of my inverter pic, it is functioning greatand shows precisely how much juice the batteries still have. I have included a small relay that is powered by the last LED to auto shutoff the inverter once last LED is off.

18> Also included an optional "Overload circuit", it is very easy to build and can be calibrated to the desired overload current threshold cutoff point through thepotentiometer VR1.

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

R1 is rated 5watts for inverters upto 1000 watts. For bigger versions of the inverter like 1000 to 3000 watts inverters, replace R1 (1 ohm, 5watts) with (1 ohm, 17watts)which should handle loads upto 10 VA.Make sure you install a proper relay to handle big current drains.

19> Please guys take your time to read and understand my notes, browse and read the posts and questions asked by others because there are many usefulinformation listed in replies. The main reason for me not answering your question is because it has already been asked before and answered upon.

20> It would be nice and inspiring for others if you take some photos and show us how you built your version, any additions to the circuit are mostlywelcomed to be listed here, we can all benefit from them.

21> Please click on the "I've made it" button/icon if you did build the circuit so I know how many people benefit from this design.

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

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Comments

50 comments Add Comment view all 1530 comments

 Aldrin Dalagan says:  Oct 6, 2014. 2:56 AM  REPLYGood day sir, i have a few questions..

1.Is this circuit of yours can run electronic gadgets such as laptops,etc?

2.Is it the output waveform is square wave when we don't connect the filter caps 2.2uF and 0.1uF's?

 chivindwe says:  Sep 29, 2014. 11:28 AM  REPLYSir, this circuit keeps blowing off my 2n6277 transistors at start up. The two banks of transistors are isolated and I am using a 36V bank of butteries.Could it bethat my transformer is too big? I have also since put the cooling fans on top to extract heat instead of blowing from below. I have been testing with a pair oftransistors at a time (to get 250W) on this transformer hopping to get satisfactory results before I switch on all the 48 transistors but to no avail. Each time I try toswitch on, the 36V burns my test pair of transistors on this huge transformer and that has not made me confident to load the whole set of 48 transistors. It isparticularly the base-emitter junctions that gets cooked. I also have the feedback transformer connected ok. Please help.

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

 nickk says:  Sep 30, 2014. 10:14 PM  REPLYNo the transformer size does not matter. It seems your pinout connections on the 2N6277 are wrong, look into that. Also check if your transformer isfunctional by disconnecting it and applying to it 220vac and testing to see if you get 36-0-36 on the other side.

 chivindwe says:  Oct 2, 2014. 1:09 AM  REPLYThank you Mr. Nickk. I think that my beloved transformer was the problem. Yes applying to it 220vac was giving me 36-0-36 on the other side. However,applying to it 36-0-36 was immediately sucking in 10A even when the other end was still open. This means my test pairs of transistors were beingsubjected to 360W of power. I have sing ordered a new 48-0-48 to 220 transformer from somebody who winds transformers. I think things will be finenow. I will report back in two weeks time. Have a blessed day today!!

 Vickylbee says:  Sep 27, 2014. 5:51 AM  REPLYHello Nickk,

Firstly i want to thank you for your assistance and generosity.

I have reconstructed my circuit on a PCB but i still got the following problems:

1) the output voltage is about 110Vac, then after some time it drops to 100Vac, 97Vac and then 87Vac...

2) the input voltage for T2 from the center to each end terminal is about 7.5Vac. My battery voltage is 12.4Vdc though

3) the voltage at pin 11 and 14 are 3.5Vdc

I have attached photos. So what could be the problem here, please.

Inverter Construction.docx7 MB

Inv1 MB

Inv2867 KB

Inv31 MB

Inv41 MB

Inv51 MB

 nickk says:  Sep 28, 2014. 2:14 AM  REPLYIs your regulator 7808 ?

 Vickylbee says:  Sep 28, 2014. 1:41 PM  REPLYYes, its 7808. See photos- I haveadded it again...

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

 nickk says:  Sep 30, 2014. 10:16 PM  REPLYplease replace by 7812 and send feedback.

 Vickylbee says:  Sep 28, 2014. 1:52 PM  REPLYI am suprise that it has not been a problem or noticed by others, but by the formula you gave, F = 1.3 / (RxC), then the 100k resistor and 100k pot R2 willnot give f=50Hz, except 200k resistor is used. Can you please also expain that to me. I also notice varying R1 did not change my output voltage

 AliiA says:  Sep 28, 2014. 12:46 PM  REPLYDear Sir Would you please let me know what the characteristic of transformer , I maen the Number of turns In primary and secondary and thickness ofdiameter in mm for each side .

With my best regards

 mohamed.ibrahimgaber says:  Sep 28, 2014. 12:54 AM  REPLYGood morning sir ;

i have the same question of Vickylbee

but the o/p voltage of me inverter is around 196 volt but if i loaded it ,the voltage drop occur and became 170

so the feedback doesn't work or what sir

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

what should i do ?

thank you

 nickk says:  Sep 28, 2014. 2:19 AM  REPLYPlease upload some pics showing your setup

 mohamed.ibrahimgaber says:  Sep 28, 2014. 11:15 AM  REPLYhello sir

i'm sorry i can't upload pics but i did as this one attached

can u explain how ic sg3524 recover the drop in voltage and how the

feedback work

thank u

 jjaan says:  Sep 27, 2014. 2:35 AM  REPLYHi sir kindly tell me that i am working on solar based motor system so i am getting very high costs from market i have to build my own and i like urs so is itefficient for 200w panels to used for water pump1/2 horse power ?secondly sir if yew have charge controller circuit diagram then needed urgently forimplemantation?thanks

 NelsonC1 says:  Sep 26, 2014. 4:53 PM  REPLYhi nick, i'm planning to used IRFP260N to produce a 1500 watts 24 volt how many mosfet can i put in the circuit. thanks!

 Vickylbee says:  Sep 12, 2014. 3:20 AM (removed by author or community request)

 Aldrin Dalagan says:  Sep 15, 2014. 7:58 AM  REPLYI think there's something wrong in your wirings or connection.. I got that low voltage too when i accidentaly connect the TIP122 in wrong connections. Ormaybe you have a wrong pcb design.. just an opinion sir.

 Vickylbee says:  Sep 16, 2014. 5:26 PM  REPLYI disconnected the entire circuit and rebuilt it but I still got 54V. I use bread board so its easy to reconnect or modify, then i would transfer to PCB if itworked on the breadboard. Ok... I will reconnect directly to a PCB to see if it works fine. Thanks, Aldrin for your insight!

 Aldrin Dalagan says:  Sep 26, 2014. 2:17 AM  REPLYYou are welcome sir. I just want to know you that i built this circuit and it's working great! Thanks to Nick for his GREAT FREE SCHEMATIC!!Godbless

 nickk says:  Sep 14, 2014. 8:09 AM  REPLYplease upload photos of your work.

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

 Vickylbee says:  Sep 16, 2014. 6:37 PM  REPLYI have uploaded the photo. I constructed mine on a breadboard for ease of modifications, and would transfer to PCB if it worked. Though my constructionlooks untidy but I actually test all connection to ensure they are correct. I have rebuilt it at least 6 times and its frustrating that i get 40-55Vac each time. Iwill reconnect on a PCB to check if that solves the problem.

Inverter1 MB

 nickk says:  Sep 16, 2014. 9:24 PM  REPLYHi, I can't open this file. I need to see what you're doing, trans size, batt. size..etc.

I can blindly assure you that 1000's of people built this inverter and they are all happy. There is some mistake somewhere, I suggest you build itdirectly on a pcb board.

 tmsantos says:  Sep 24, 2014. 8:27 AM  REPLYcan send a video image with working

 baldrin123 says:  Aug 7, 2014. 1:55 AM (removed by author or community request)

 sanmlight says:  Aug 7, 2014. 5:52 PM  REPLYtry to remove the diode in the transformer.... i have made this circuit and it is working very well without the diode.

im using a 12-0-12 1500 Watts transformer

Thanks to nickk for sharing this... God Bless!

 MOHAMED0MAHROUS says:  Sep 22, 2014. 4:35 PM  REPLYdoide is important to safe transistor or any component from short or back voltage

 nickk says:  Aug 7, 2014. 10:31 PM  REPLYHello,

You need a battery power source to power up this circuit, you can't run it on some small transformer as a DC source.

 shida says:  May 17, 2014. 3:37 PM  REPLYhi nikk plz can you help mi

am dont speek englash but

ﺮﻜﺸﻟﺕ ﻞﻛ ï»šï»Ÿï» ïº®ï»¤ïº˜ïº´ï»£ ﻂﻟﻮﻓ 120 ﻲﻨﻌﻳ ﺕﺕïºïºŽï»„ﺑ 10 ﻦﻣ ﻥﻮﻜﺘﻳ ﺮﺗﺮﻴﻔﻧﺕ ﺔﻋﺎﻨﺻ ﻲﻓ ﻡﺪﺨﺘﺴﻤﻟﺕ ﺖﻔﺻﻮﻤﻟﺕ ï»ïº• ïºï»®ïº˜ïº³ïº°ï»³ïº°ï»§ïº•ïº®ïº— ﻉﻮﻧ ﻮﻋ ﺎﻣ ﻚﻟ ﺪﻴﺣﻮﻟﺕ ﻲﻟﺕﻮﺳ

 Eng_MYM says:  Aug 2, 2014. 2:52 AM  REPLYﻲﺑﺮﻋ ﻢﻠﻜﺘﺘﺑ ﺶﻣ ﻱﺩ ﺱﺎﻨﻟﺕ .... ﻱﺰﻳﺰﻋ ...200 ﺪﺤﻟ ﻞﻤﺤﺘﺴﻳ ﺓﺮﺋﺕﺪﻟﺕ ﻲﻓ ﻲﻠﻟﺕ ﺖﻔﺳﻮﻤﻟﺕ ﻥﺇ ﻚﻟﻮﻗﺃ ﺕﺣﺃ ﻦﻜﻟ IRFP2502 ﺮﻣïºï»®ï»”ﺴﻧﺕﺮﺘﻟﺕ ﺲﺑ ﺮﻴﻕﺗ ﻦﻜﻟ ﺓﺮﺋﺕﺪﻟﺕ ﻲﻫ ﻲﻫ ﻲﻨﻌﻳ ... ﺖﻟﻮﻓ ...12- 0 -12 ﻕﺪﺑﻥﻮﻜﻳ120-0-120ﺯï»ïºŽï»‹ ﺖﻧﺇ ﺎﻣ ﻱﺯ ﺔﻋﺎﺘﺑ ﺕïºïºŽïº¨ï»Ÿïº• ﺎﻌﺒﻃ ï»ï»ªï»¬ï»¬ï»¬ï»¬ï»¬ï»¬ï»¬ï»¬ï»¬ï»¬ï»¬ï»«.... ﺢﺻ ﻲﻣﻼﻛ ﻊﻠﻄﻳ ï» ïº®ïº˜ïº´ï»³ ﺎﻨﺑïº

 nickk says:  Sep 16, 2014. 9:42 PM  REPLY;)

Location:Beirut - Lebanon

 makram.morris.9 says:  Aug 21, 2014. 6:03 AM  REPLYﺢﺻ ﻚﻣﻼﻛ ﻼﻌﻓ eng_mym

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

 makram.morris.9 says:  Aug 21, 2014. 6:07 AM  REPLYmr:nickk i have a problem i use battery 12v 7ah but it empty fast about 1min why

thank`s

 nickk says:  Sep 16, 2014. 9:39 PM  REPLYBecause it is 7ah ! You need at least 70amps.

 makram.morris.9 says:  Aug 21, 2014. 6:12 AM  REPLYand the best battery charger circuit you have thank`s

 pitong says:  Sep 3, 2014. 8:10 PM  REPLYsir can i ask for complete list of materials,tanx

 nickk says:  Sep 16, 2014. 9:34 PM  REPLY:)

 Aldrin Dalagan says:  Sep 7, 2014. 12:14 AM  REPLYHi sir Nick! Hope you a have a good day. I just wanna ask if it's okay to use UC3524 instead of SG3524? I think they're both equivalent. That's the one ibought here. Thank you for your GREAT SCHEMA.. I'm so thankful that there's a very nice person like you sharing your knowledge.

 nickk says:  Sep 16, 2014. 9:30 PM  REPLYHi Aldrin, Yes they are the same, I've answered a similar question earlier.

 Ctstrphy says:  Sep 10, 2014. 8:19 AM  REPLYexcuse me sir,, it is about your inverter that is pure sine wave in using a 16f628a,, cause we have a little probem,, in oscillator.... cause there is no output inPWM in the PIC but if we touch the oscillator the pin 6 and 7 will have a output.. what seems to be the problem with this..? hope you will see reply it sir. thankyou.

 nickk says:  Sep 16, 2014. 9:29 PM  REPLYYou're posting in the wrong place.

 Ctstrphy says:  Sep 10, 2014. 4:38 PM  REPLYsir nick help me.. their is something wrong in our inverter using 16f628a,, because their is no output in PWM unless I touch the 20MHz crystal Oscillator. if itouch the Oscillator their is a output but if i will not touch it their is no output... help me sir...

 nickk says:  Sep 16, 2014. 9:29 PM  REPLYYou're posting in the wrong place.

 adsamtzy says:  Sep 11, 2014. 7:14 PM  REPLYThank you sir, i build this circuit but the oscillator sg3524 get hot, sir what could the fault in the circuit? and i have the overload circuit sir how can calibratethe circuit, secondly if i want to build a 3kv inverter sir how could i select R1 that is current sensor resistor. Thanks.

 nickk says:  Sep 16, 2014. 9:28 PM  REPLYthe 3524 should not be hot at all, there is something wrong with your wirings. Make the basic circuit work first before calibrating anything else.

 tmsantos says:  Sep 11, 2014. 8:31 AM  REPLYpodría enviar por el correo electrónico que quiero hacer uno para conmigo gracias tacisio@gmail.com

 nickk says:  Sep 16, 2014. 9:26 PM  REPLYSorry, but I don't speak your language.

http://www.instructables.com/id/250-to-5000-watts-PWM-DCAC-220V-Power-Inverter/

 pitong says:  Sep 3, 2014. 7:51 PM  REPLYsir nick can i ask,im planning to do this project, what if the power transistor 2N6277

is not available here in my country ill replced it with 2 x 2N3773, these 2 x 2N3773 must be in parrallel connection?

 nickk says:  Sep 16, 2014. 9:25 PM  REPLYAny equivalent should work.

 Aldrin Dalagan says:  Sep 15, 2014. 7:52 AM  REPLYYes, you can replace/substitute it instead of 2N6277. Parallel connection.

 Vickylbee says:  Sep 16, 2014. 6:30 PM  REPLY

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