pure sine wave inverter 48vdc

Discussion in 'The Projects Forum' started by rony_321, Jun 4, 2011.

  1. rony_321

    Thread Starter New Member

    Jun 4, 2011
    hi I have been working since 2 years in designing a pure sine wave inverter with the following specifications:
    h-bridge with 2 ir2110 and step up iron core transformer to 220v,with 19350hz sampling frequency.
    I used the Microntroller pic18f2331 using assembly language.
    Every thing was okay, I first began with 12VDc bus,the output signal was perfect in resistive load,and inductive load with high power factor like fan,but with low power factor like drills booster pumps, the pure sine wave signal is distorted a little, but this was also okay,I didn't face any problem neither at 12VDC nor at 24VDC, I always work with RCD suppressing snubber, and high input capacitance of about 24000uF for 24VDC, I tried a maximum load of 1200W for several hours, the mosfet's heat(irfp064N) was acceptable and no problem, I always use a 10 ohms resistor for the gate to avoid switching losses.the output is regulated very well with constant value 227.6 volts always.
    note that i use filtering at the output by a capacitor of 4.7uF for 24VDC(1200VA ie 900watt)

    the problem is:when using a DC bus of 48VDC, designing an iron core transformer of 28vac-225vac, the Mosfets irfp4710 were blown off when i put a transformer, but with different resistive loads, every thing was okay, good output signal.

    I tried several issues to solve the problem, like:
    1)stabilizing the secondary side of IR2110 by putting capacitor of high value to avoid voltage drop which may cause output garbage
    2)cancelling snubbers.
    3)trying anather transformer.
    4)increasing dead time.
    the mosfets exploded again and again,

    I tried to use a smoothing inductor (which causes voltage drop and low efficienty inverter), the inverter works but with low voltage.

    I don't know what to do but I think of lowering the sampling frequency inside my program!!!
    if any one have an idea what to do, please help

    N.B: I don't use ferrite because it is not available in the market in Lebanon, I prefere to use dc dc boost converter go up to 340, and then use LC filter.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    By "sampling" frequency, perhaps you mean "switching" frequency.

    Like all electronics, we need to see a schematic to know how it works.

    Like all sine wave inverters, you do not have to go to many watts in the output before a generator become very attractive (possibly the same one you use to recharge the batteries).
  3. rony_321

    Thread Starter New Member

    Jun 4, 2011
    I don't have a schematic now, but yes I mean switching frequency

    New Member

    Sep 18, 2012
    Please can you send me the circuit diagram of 24-48v dc high bridge transformer inverter for my project thanks
  5. Papabravo


    Feb 24, 2006
    I think the OP is long gone having made only two posts. Why would you want a schematic for a device that blows output transistors. Wouldn't you prefer something that works? I'm just asking.
  6. gober

    New Member

    Aug 24, 2010
    Hey rony, can you please post your program and schemtic. i'm designing my own sine wave inverter but using push pull topology and i can rally use your results and ideas to improve mine.
    hope you will post asap
  7. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    For any and everyone who wants this schematic for a quad IRFP4710 MOSFET destroyer, I offer the following:


    It is equally capable of destroying any and all MOSFETs presented to the in feed bin.
  8. gerty

    AAC Fanatic!

    Aug 30, 2007
    Looks very efficient too !!!