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DC-DC half bridge converter and simulink

Discussion in 'General Electronics Chat' started by Varkatzas, Oct 31, 2012.

  1. Varkatzas

    Thread Starter New Member

    Oct 22, 2012

    I´m simulating a DC-DC converter in half bridge configuration in Simulink. Im having troubles in the Buck converter with the output ripple current at the capacitor. As im designing for a Buck and Boost converter, i use the greatest values. So far im simulating in ideal conditions. This is the information:

    P=7.5 kW f=80kHz

    Buck: Boost:
    Vi=750V Vi=187.5 - 375V
    Vo=375V Vo= 750 V
    D=0.5 D= 0.5 - 0.75

    With this data, the greatest values are for C=12.5 uF and L=585.94 uH

    The problem here is, that as i simulate de Buck with these values for C and L, the ripple current does not have the expected amplitud - 0.5 V - but has 2mV.

    I know that the smaller the ripple the better, but it doesn´t match with the Voltage Ripple equation:

    ΔVc= ΔI/(8fC)

    I dont know what im doing wrong. By any chance could be that in the equation fxC=(8e4)(1.25e-5)=1 ? Does it have anything to do?

    Thanks for your help.