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RC snubber high temperature.

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  • RC snubber high temperature.

    I am trying to design an IGBT driver, to commutate 1600W at 330V DC.
    I am driving it with Arduino at 8kHz. The load is consisted of heaters, that have parasitic inductance of 30uH. I am designing in LT spice the whole circuit and see the power dissipation on the R of the snubber is about 3W. I am not sure if it is normal or not, considering the total load power.

    I can add 5W or 10 W resistance, but I will decrease the effect of high temperature, but the 3W dissipated power will stay, and I am not sure if it is effective in terms of efficiency and so on. or it is normal? My R is 5.6 Ohms, and C is 22nF, and the temperature over R is higher than 100 degrees. If I lower the resistance the dissipated power goes to 1.5W ( which is also high temperature over 3W resistance) but the snubbing of the signal goes worst.

    Anny suggestions??

  • #2
    What is the capacitance if the IGBT? to be effective, C needs to be 5-10 times the IGBT capacitance. The power in the resistor should be independent of the resistor value, but the resistor should be about 0.6 times the characteristic impedance.

    This reduces the Q of the ringing, but should NOT be confused with a clamp.