PWM inverter circuit - 500 Watt low cost

This PWM inverter circuit can be build within rupees 180(mosfet version) and rupees 350(triansistor version), price esteemed for only circuit, except transformer and battery, cabinet etc…

The triansistor power section is as pictrure as the one posted, made by 6 nos of 2N3055 triansistor, both T1 and T2 are to be made identical, and if you want mosfet, then use P55NF06 mosfet, having 3 mosfet parallel, with each one having a resistor of 22 ohm in series to the Gate pin to the T1 or T2 base point.

The transformer is costly, better build it yourself or by any local transformer repair shop by an old 750VA~1KVA stabilizer transformer. The primary wire guage is 13 swg, and secondary is 23 or 22 swg.

The main feature of this inverter is, this is a PWM based circuit, and output voltage stables at any load, same thing that happens to SMPS.

PWM inverter circuit diagram Parts list

1. I.C  SG3524 x1                                           15/-
2. total 12 pcs resistor                                     6/-
3. total 4 pcs capacitor                                     4/-
4. Diode BWY51(can use IN4007 also) x1   2/-
5. 1mH inductor                                              3/-

——————————————————-————
TOTAL WITHOUT POWER SECTION           30/-

power section

• MOSFET: 6pc P55NF06 with heatsink 150/-   +board = 180/- ~200/- (appx 4USD)
• Transistor: 12pc 2N3055(good quality costly one) with heatsink  320/- +board= 350/-~370/- (appx 7.5 USD)

Comments on this article before 07-12-2011

• sunny on April 2, 2011 - 3:35 pm

  

  hi
  can u have picture the circuits . i have 12 0 12 transformer
  when i Purchased 3055 amp the quality is very good but after some time pcb is down
  i change the circuit pcb .but quality is down

  Arup Reply:
  April 7th, 2011 at 4:24 pm@sunny, rewind transformer.

  Manu Reply:
  October 24th, 2011 at 5:42 amThank for your low cost high value circuits and good description..I found free energy from magnets. I dont know it is true or false.dear sir,
  do u have any idea about that….
  thank you…waiting for your valuable reply….manu.

  Arup Reply:
  October 24th, 2011 at 1:50 pmFree energy from magnet? Sounds impossible. Can you describe it to me?

  bias Reply:
  November 3rd, 2011 at 6:08 pmHello Friend, please give the circuit clearly, I can not understand the circuit because of very small size, I want to make that type of inverter, so please help, if you send me clear circuit to my mail address (agnesanisavi@alice.it), this will be very helpful to me.

• Dhrubajyoti Dey on May 20, 2011 - 3:48 am

  

  Hello Friend, please give the circuit clearly, I can not understand the pwm inverter circuit diagram because of very small size, I want to make that type of inverter, so please help, if you send me clear circuit to my mail address (dhrubadey@yahoo.com), this will be very helpful to me.

  Arup Reply:
  May 20th, 2011 at 9:06 pm@Dhrubajyoti Dey, I have repaired the link. You can click on the image to see larger size.

  Andrea B Reply:
  November 2nd, 2011 at 6:19 pmHello Friend, please give the circuit clearly, I can not understand the circuit because of very small size, I want to make that type of inverter, so please help, if you send me clear circuit to my mail address (agnesanisavi@alice.it), this will be very helpful to me

  Arup Reply:
  November 2nd, 2011 at 6:26 pmClick on the image.

• Dhrubajyoti Dey on May 21, 2011 - 4:31 am

  

  dear Friend, I just want to know that did u test or make this inverter with 12v lead acid battery ? I have made many transistor inverter with 74LS112 IC Board. Does this SG 3524 ic oscillation circuit is better than that ?

  Arup Reply:
  May 21st, 2011 at 7:23 am@Dhrubajyoti Dey, 74LS112 just outputs 100% duty cycle square wave output, but this SG 3524 can supply PWM output so you can easily create a modified sinewave inverter. Hence, SG3524 is better than 74LS112

• Dhrubajyoti Dey on May 22, 2011 - 7:54 pm

  

  Dear Friend, I can not seen any preset to adjust the frequency or inverter output Ac voltage. Is it fixed, which resistances are substitute of those preset ?

  Arup Reply:
  May 22nd, 2011 at 8:48 pmThe frequency is fixed to 50Hz.

  Dhrubajyoti Dey Reply:
  May 22nd, 2011 at 9:09 pmDear Friend thanks for your pompt reply. 50hz. is fixded that is very good, but transistor output ac voltage is also fixed i think. how can i change this, whats the voltage you fix for the circuit. actually i need output voltage 240volt, so i ask you.

  Arup Reply:
  May 22nd, 2011 at 9:25 pmAt output, there is a 200K resistor, just replace it with 220K valued resistor to get 240Volts output.

• Dhrubajyoti Dey on May 23, 2011 - 3:43 am

  

  dear arup, at first circuit, Base and emitter pin is connected with a 100ohm resistance of T1 and T2. My question is that is this only for amplifying the gain and for the first transistor or this continues with all the transistors ? If you give a total circuit picture with all transistors, then it will much better for me and easier to understand. If I will make this circuit with mosfet will it better than transistor ? please give a circuit with all mosfet and connection.

  Arup Reply:
  May 23rd, 2011 at 12:33 pmMosfets are definitely better than transistors. For your need, I’ll publish an article of PWM mosfet based inverter shortly. Stay tuned.

• Dhrubajyoti Dey on June 3, 2011 - 4:07 am

  

  Dear Arup, Please try to post a oscillator circuit with SG3524 with mosfets as early as possible. I have to build an inverter very quickly. Thanks in advance.

  Arup Reply:
  June 4th, 2011 at 7:36 pmI have sent you the diagram by email. Didn’t you received it?

  Dhrubajyoti Dey Reply:
  June 7th, 2011 at 4:13 amThanks for your cooperation. I have got it.

  vinod Reply:
  July 16th, 2011 at 5:24 amSir,
  please send me the 500w inverter circuit with mosfet……please….my email id is vinodao@gmail.com

• Srinivas on June 16, 2011 - 9:28 am

  

  sir,

  The Circuit is excellent.
  I am an electronic hobbyist
  please send me the circuit with preset to adjust the frequency and Change over from AC mains with single relay and Charger circuit witn LM317. Thank you in advance

  Arup Reply:
  June 16th, 2011 at 8:57 pmNo frequency change needed. The circuit is already set to a fixed 50Hz which would be accepted in all appliances.
  I’ve noted your request of changeover circuit and will publish it after a few days. And, LM317 is a voltage regulator IC, not a charger IC.
  For quick notification of the publication of your required post, I’d advice you to subscribe to updates by email through the box above.
  And yes, thanks for dropping a comment. Happy to see you found this useful.

• Vinod.a.o on July 15, 2011 - 4:40 am

  

  Sir,

  This circuit is very good and easy to made. I request you to please send me a oscillator circuit with SG3524 with mosfets.

  Thanking You

• nishant upadhyaya on July 17, 2011 - 6:13 pm

  

  Dear Arup, Please try to post a oscillator circuit with SG3524 with mosfets as early as possible. I have to build an inverter very quickly. Thanks in advance.

  Arup Reply:
  August 11th, 2011 at 10:34 amUse this same circuit. Just use MOSFET instead of the paired transistors.

• Imran Najeeb on August 12, 2011 - 7:13 am

  

  Please can you send me complete circuit diagram for 500 Watt low cost PWM inverter circuit. Either it uses a Microcontroller or Simple ICs. I am Intermediate in electronics so please a little help is also required

  Arup Reply:
  August 12th, 2011 at 7:18 amMicrocontrollers!
  Hmm. A good idea to easily make sinewave inverteres by generating sinewave by PWM, or D/A ladder.
  Thanks for the idea. I’ll soon publish a circuit, program and article for MCU based inverter.
  Stay tuned, Stay subscribed to get notified.

• Chinmoy Mitra on September 24, 2011 - 7:29 pm

  

  Dear Arup, 220V output is shown OK, but what about the 5V PWM reference wires? Where do they go? Please clarify. Thanks.

  Arup Reply:
  September 25th, 2011 at 12:54 pmYou can see 5V PWM reference wires comes from a resistor based voltage divider from the output and goes to SG3524IC.

• ahmed j on September 30, 2011 - 8:35 pm

  

  hi evry1 please who can tell me the answer.what is the range of the duty cycle adjustment of sg3524

  Arup Reply:
  October 1st, 2011 at 4:06 pmNormally we get 20% to 70% duty cycle or PWM from SG3524. But the absolute range is 0% to 45% for each channel that means total 90% max PWM.
  Get more data http://www2.microsemi.com/datasheets/sg1524.pdf

• patrick on October 2, 2011 - 3:47 am

  

  Hello Arup,
  Do you have any circuit related to 750 VA UPS

• salman on October 2, 2011 - 7:51 am

  

  well i’ve been working on inverter for last 4 months, Arup can you plz tell me what is the function of those 6 transistors in power section connected to T1 and T2? I know that we take supply from the all the bases of the 6 transistors which is further connected to transformer, but if T1 and T2 are switching the pulse then what is the function of those 6 transistors?

• rohit on October 2, 2011 - 12:41 pm

  

  Hello Arup,
  Can u provide more details about the transformer, such as how many windings on the primary and secondary. details of the core etc.,
  thanks for everything.

• patrick on October 2, 2011 - 1:54 pm

  

  Hello Arup,
  Do you have the details of the transformer, such as how many winding in primary/ seconday what is the thickness of wire details of the core etc.,

  thanks for the information

• Arup on October 4, 2011 - 3:31 pm

  

  @patrick,
  750VA UPS is nothing but a complete inverter. You can see a complete circuit for the same in my blog. Thanks.
  @salman,
  The switching pulses have to be amplified a lot to drive the transformer.
  @rohit,@patrick,
  It would be best if you buy a ready-made inverter transformer. I have made transformers, and believe me, it’s a dirty job.

• salman on October 5, 2011 - 3:18 pm

  

  so is it a voltage amplifier circuit or power amplifier circuit? moreover my amplifier circuit works in common base configuration, which configuration I should use for those transistors which will be used for switching pulses?

  Arup Reply:
  October 7th, 2011 at 8:53 amUse them as darlington pair for high gain.

• Alex on October 8, 2011 - 2:09 am

  

  Hello how is everyone good to know there is a forum like this where we can get such a good circuit. Mr Authour I would like to know what kind of output wave form this circuit produces. Is it modified sine wave . I would like to build it , thank you waiting for your reply.

  Arup Reply:
  October 8th, 2011 at 6:25 amHi, this is a blog and not a forum.
  Modified sinewave requires fixed 50% d.c in PWM. In this circuit the PWM varies to compensate the load. SO it’s not a modified sinewave, but it will act like sinewave if you use larger capacitor at output.

• salman on October 11, 2011 - 2:42 pm

  

  If I connect them in darlington pair still I would need step up transformer? If yes then what is the advantage of using darlington pair over common base configuration (cascade) ?

  Arup Reply:
  October 12th, 2011 at 2:42 pmAdvantage of darlington: High gain(hfe, or beta).Transformer is much in any kind of such inverter to boost voltage.

• Matt on October 18, 2011 - 3:46 am

  

  Pls, how can i use my inverter transformer to charge my inverter battery and together with the relay as well. And while is my inverter transformer is making small noice when connected to battery although is working?

  Arup Reply:
  October 22nd, 2011 at 3:37 pmSmall noise is fine.
  Just disconnect power supply(+ve) to controller board and connect AC mains line to output of Transformer and it will be in charging mode.

• Matt on October 23, 2011 - 7:22 am

  

  Pls, how is bicycle 6vac or 12vac dynamo work. Can it work for 15 hours non stop?

  Arup Reply:
  October 24th, 2011 at 1:48 pmYes. But you need proper lubrication.

• Matt on October 27, 2011 - 2:25 pm

  

  My batery(12v 70ah) for inverter is not charging. What should i do

  Arup Reply:
  October 27th, 2011 at 3:26 pmWash battery and reinstall Acid.

• Matt on November 1, 2011 - 12:44 pm

  

  Can someone convert 12vdc produce from dynamo to AC, If not why?

  Arup Reply:
  November 4th, 2011 at 3:31 pmYes we can. We’ll require a DC motor and AC dynamo.

• THRASOS on November 8, 2011 - 5:45 pm

  

  Hello sir
  I made some solar panel by my self and i bought some ready made inverter ,and i want to make one follwing your sircuit.
  I already erdered some components.
  Does this sircuit has a fuction of overload , and if not can this be done with a optocoupler .
  Thank you
  Thrasos Christou

  Arup Reply:
  November 15th, 2011 at 5:12 amYou can detect overload the same way output is measured. You need to trigger a transistor in case of overload and that transistor will switch the shutdown pin (pin no 9).

• Matt on November 11, 2011 - 8:40 pm

  

  Tell why we use regulator 7809, not 7805 or ..12.

  Arup Reply:
  November 15th, 2011 at 5:11 amWhere 7809 is used?

  Matt Reply:
  November 15th, 2011 at 11:30 amYes, in the inverter circuit. Why using regulator 7809, not 7905 or ..12

  Arup Reply:
  November 15th, 2011 at 12:17 pmShow me where in the above circuit a 7809 is used.

• sparkie on November 24, 2011 - 10:09 pm

  

  Good work Arup, please tell me is the transformer is a 12-0-12 center tapped transformer.
  Also i intend to use mosfets, if i replace P55NF06 with IRFZ44N will the gate resistance remain 22ohms, if not what value is it?
  Does the 100 ohm base at the mosfet gates remain constant in this case?
  Also what is the wattage of the resistors and capacitor voltages.
  Thanx

  Arup Reply:
  November 25th, 2011 at 10:34 amYes 100ohm resistor is common at the GATE of the MOSFET.
  Which resistor and capacitor?