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  1. #1
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    DC-AC Inverter

    Hi,

    I need to design dc to ac inverter from DC +12Volt to AC 230. But i need to use PWM to control the inverter. I using "Sinusoidul Pulse Modulation" to control the MOSFET transistor.

    When i using PWM to control the MOSFET transistor (inverter). The PWM signal will distortion. I have testing connect the AC load (lamp 230Vac/5W) , the output voltage from inverter drop to ~120Vac.

    How to control or maintian the output voltage always 230Vac when connect AC-Load?

    •   Alt4th September 2004, 12:50

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    Re: DC-AC Inverter

    Feedback loop will regulate the o/p voltage and also stabilize the ckt.

    bimbla.



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    Re: DC-AC Inverter

    Quote Originally Posted by bimbla
    Feedback loop will regulate the o/p voltage and also stabilize the ckt.

    bimbla.
    can u explain more detial about it. TQ!



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    Re: DC-AC Inverter

    Your design is of the driven type.
    To regulate the o/p voltage, you need to feed part of the o/p voltage (step-down tapping---->rectify---->filter) and give it to the input. The fed back signal will generate an erroe voltage and o/p correction will take place based on this error voltage.

    As far as the o/p waveform is concerned, you have not included (indicated) any form of filter to remoce the carrier. This o/p filter will integrate the pulses to give you sinewave.

    bimbla.



    •   Alt5th September 2004, 03:49

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  5. #5
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    Re: DC-AC Inverter

    Quote Originally Posted by bimbla
    Your design is of the driven type.
    To regulate the o/p voltage, you need to feed part of the o/p voltage (step-down tapping---->rectify---->filter) and give it to the input. The fed back signal will generate an erroe voltage and o/p correction will take place based on this error voltage.

    As far as the o/p waveform is concerned, you have not included (indicated) any form of filter to remoce the carrier. This o/p filter will integrate the pulses to give you sinewave.

    bimbla.

    U mean the o/p voltage(AC 230Volt) need to step-down tapping---->rectify---->filter.
    So that,
    step 1) the filter signal will feedback to input
    step 2) than compare the input signal with the feedback signal the
    step 3) than generate the error signal
    step 4) than ??

    can you have a block diagram from me, may be i more understand from your block diagram. Your block diagram size don't so big because i no enough point to down load. TQ

    How to do the o/p filter will integrate the pulses to give you sinewave?



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    Re: DC-AC Inverter

    In your case, if the o/p voltage reduces, increase in sine wave amplitude is required and vice- versa.

    The o/p filtre can be nothing more than an LC filter acting as a low pass (integrator) circuit.

    If you still do not get the idea, I'll try and come up with some refrences or give you a block dia.

    bimbla.



    •   Alt5th September 2004, 12:33

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  7. #7
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    Re: DC-AC Inverter

    Quote Originally Posted by bimbla
    In your case, if the o/p voltage reduces, increase in sine wave amplitude is required and vice- versa.

    The o/p filtre can be nothing more than an LC filter acting as a low pass (integrator) circuit.

    If you still do not get the idea, I'll try and come up with some refrences or give you a block dia.

    bimbla.
    if the sine wave is distortion are u sure the amplitude can increase? i am using the IC 8038 Waveform Generator.

    i have no idea about the o/p filter.

    Bellow is my schematic circuit diagram for Inverter-Controller



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    Re: DC-AC Inverter

    Would you please STOP uploading your circuits as big proprietary file formats????

    People are not gonna download a 1.7MB file and help you if it just contains a simple block diagram...

    Please use either Acrobar PDF or GIF/JPEG for circuits!!

    No more word/powerpoint documents please!
    Next time warning...



  9. #9
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    Re: DC-AC Inverter

    Thanks SuperMod, makes my job a little easier.

    Your circuit is very simple. Some basic rules of inverter such as complimentary drive with deadzone to drive the o/p bridge are missing. This will result in decreased efficiency, o/p distortion and heating.

    I recommend you hit the books and work on some basics. As far as ready reference is concerned, get hold of 12V DC to 230V AC inverter circuit published in ElekTor*

    bimbla.



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    Re: DC-AC Inverter

    I just realised that you are comparing sine wave with astable o/p. You have missed converting astable o/p to trianglular wave.

    You should brush- up your basics. (I hope you take it positively)

    bimbla.



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    Re: DC-AC Inverter

    Quote Originally Posted by bimbla
    I just realised that you are comparing sine wave with astable o/p. You have missed converting astable o/p to trianglular wave.

    You should brush- up your basics. (I hope you take it positively)

    bimbla.

    Thank you for your suggestion i will brush- up my basics but now i no have time. I need to complete my project 2 month and this is just of the one part i need to do. Can u help me, i really need your help. How can i improve my inverter? How to design converting astable o/p to trianglular wave?



  12. #12
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    DC-AC Inverter

    Consider Close Loop Control through output volatge feedback .. A pid may be considered ...



  13. #13
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    DC-AC Inverter

    I just realised that you are comparing sine wave with astable o/p. You have missed converting astable o/p to trianglular wave.

    You should brush- up your basics. (I hope you take it positively)



    •   Alt10th August 2006, 12:44

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  14. #14
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    Re: DC-AC Inverter

    It's called DAC. Digital-Analog Converter. You can find info. easily from the web.
    Cheers.



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    Re: DC-AC Inverter

    you can type " inverter dc ac power schema " at yahoo search



  16. #16
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    Re: DC-AC Inverter

    Well, I've already searched through Google or Yahoo.
    I need more specific info from some experts in this board.

    Thanx anyway.



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