Compact, Ferrite Core Transformerless Inverter Circuit

The circuit diagram of a compact transformeress inverter using ferrite core inductor is shown in the following article, the image was provided to me by one of the avid readers of this blog Mr. Ritesh. The design is a full fledged configuration with includes most of the features such as ferrite transformer winding details, low voltage indicator stage, output voltage regulation facility etc.

I would appreciate if anybody could help identify the various stages, and explain them in details.

35 Replies to “Compact, Ferrite Core Transformerless Inverter Circuit”

  1. daniel

    hi sir you done a great job ,i want to build one so i need your help the IC im very confuse is it a CD 556 LM556? and if it would be possible for you to send the PCB of it i will be appreciate,thank you looking forward to hear from soon

    Reply
    1. Swagatam Post author

      Thanks Daniel,

      Any 556 IC will do, the initial prefix does not matter.
      I do not have the PCB design for this circuit, so would be unable to provide it to you

      Reply
    1. Syed Asim Ali Zaidi

      The output from that transformer where the bridge rectifier is connected is above 300v and it is high frequency. So it is rectified using high speed switching diode (ultra fast frequency) and then fed to the next mosfet bridge to produce complete AC cycle and hence the output become AC & during this process the other oscillator brings its frequency to the required frequency that is between 50-60Hz

      Reply
    1. Swagatam Post author

      when inverters are discussed, transformers by default refers to heavy bulky iron cored transformers, which is not present here, the small ferrite trafo can be considered as good as an electronic component.

      Reply
  2. Olaleye Kolade

    Thanks Mr Swagatam, you such a gift to our generation.
    I want to build this circuit, my problem is the transfo area, do you have the idea of how big the ferrite core will be and the thickness of the wire use
    2. About the circuit in the link below, can you please tell me how to connect it to inverter? As it have Load terminal /- and battery terminal /- How will I connect these terminals
    Thank

    Reply
    1. Swagatam Post author

      the inverter battery will need to be connected across the points marked "battery"

      and the supply input points of the inverter across the points marked "load"

      Reply
  3. Olaleye Kolade

    Thanks for all the design
    I build the circuit in this with SG3524 IC, I connect the 555 based output to pin 3 of IC 3524 and it works fine when I use it to power 100w bulb although I don't check the wave I don't have instrument to do that but when I connect pin 3 of the third IC 555 with 1N4148 diode to pin 11 and 14 of SG3524 IC as in the circuit below the current flunctuate to the extend that it burn some of my MOSFETs. http://3.bp.blogspot.com/-tjwhhBrw0eQ/VDyxEksqQKI/AAAAAAAAIcs/PIQ-UAsiKqo/s1600/IMAG0209.jpg
    Please where can I connect that output to. I really want to use 555 based oscillator for my design
    Regards

    Reply
    1. Swagatam Post author

      yes you can replace those resistors with diodes and connect with pin3 of IC 555 or you can keep the resistors in their positions and use the diodes separately at the bases of the transistors.

      Reply
    1. Swagatam Post author

      Olaleye, if you don't connect the diode ends to pin3 of the IC2 then how the PWMs will work? so obviously you will need to connect the diodes ends to pin3 of PWM IC

      Reply
  4. Olaleye Kolade

    Compliment of the season to you
    I did the correct by making it a transistor driver stage it works fine when I power it with low battery AmP say 12A but when I use battery of 100amp it start to fluntuate and make scaring noise . Pls what else can I do
    2. About the transformerless inverter in this post, I build the circuit without the low battery and overload detection section and it work fine, the problem am having now is which mosfet do I need to add to in other to increase the power. is it IRF740 or RFP50N06?
    Regards

    Reply
    1. Swagatam Post author

      amps actually should not have any effect unless the voltage is increased so whether it's 12A or 100Amp shouldn't make a difference as long as the battery voltage are identical? I'm unable to troubleshoot this issue…make sure you have connected protection diodes across the mosfet drain/source.

      The mosfet can be the one which has the I and V rating much higher than the required specification, meaning if your requirement consumes 12V at 50amps then the mosfet should be rated to handle 30V at 70 amps and so on.

      Reply
  5. Olaleye Kolade

    Thanks for been there for me
    Sir I have another problem with my inverter I used SG3524, its work fine on some appliances but when I use it to power small standing fan, the voltmeter just drop a little the is now making hummy noise (the inverter sound is reflecting in the fan) thereby making the fan not to roll @ high speed.
    Pls what can I do to remove to noise from the fan, I've filter the output by connecting 400v 0.22uf capacitor across the output of the transformer
    Thanks in advance

    Reply
    1. Swagatam Post author

      If the voltage is dropping that means the fan is consuming more current than the battery can supply, either the battery is underrated for the fan or may be the fan has some problems….try changing one of these and see the response.

      Reply
    1. Swagatam Post author

      check the current consumption by connecting an ammeter in series with the battery positive, if it exceeds around 60% of the battery AH then that's too high and that could be the reason of the problem.

      Reply
    1. Swagatam Post author

      Michael, you can do it by adding more number of mosfets in parallel with the existing mosfets and by appropriately upgrading the wire strand configuration of the trafo

      Reply

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