IGBT Full Bridge Output Waveform Problem

Discussion in 'General Electronics Chat' started by mrwtc, Apr 19, 2011.

  1. mrwtc

    Thread Starter New Member

    Apr 19, 2011
    1
    0
    Test circuit and waveforms shown in Fig.
    IGBTs are used 1200V150A's.
    The secondary side of the transformer is vacant, did not take any load.
    Three-phase AC is given by a regulator ,it's AC15V, the voltage is not very high because the test need ,only look at the results. when the input is transferred to AC 80V the voltage waveform without any changes.
    Question: yellow is the wave of "probe", purple is the Q1, Q4, IGBT drive signal. When the full-bridge circuit change load resistor from the transformer, the waveform change from the abnormal to normal. Why? Because the the transformer must be taken to the practical application , how to solve the problem?
     
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