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400Hz AC input rectifier

A.S.Bhushan
Expert 1060 points

Hi all,

How to select diodes in rectifier circuit for 400Hz AC input?

  • 0
    TI__Mastermind 34465 points

    Hello A.S.Bhushan,

    There is no real difference between the rectifier diodes used in a 400Hz rectifier and a 50/60 Hz rectifer.
    In both case the diodes used are commonly referred to as "standard recovery" types.
    It is more important to to be able to specify the reverse voltage rating, the max RMS current rating and the input surge ratings of the diodes.
    When these values are known you can go to the catalog or Digikey website for example and view a list of recommended parts

    Regards

    John

  • 0 in reply to John Griffin1
    Expert 1060 points
    Hi Mr. JohnGriffin,
    Thanks for your reply.

    We tested AC-DC converter, which has LISN+EMC filter+Rectifier+DC/DC converter.
    Specifications as per below
    Input : 115VAC, 3 Phase, Star , 50Hz
    Output: 24V, 10A.
    With 50Hz supply, Our module draws current approx 1.3A in EMI/ EMC test lab. Upto this fine.

    Now With the same setup, in test lab, if i will change the input frequency to 400 hz, module draws current approx 5A.
    I am suddenly surprise with this current. What could be the reason for this?
  • 0 in reply to A.S.Bhushan
    TI__Mastermind 34465 points

    Hello A.S.Bhushan,

    Your LISN+EMC Filter +D/DC converter has capacitance to  safety ground and across the AC input line.

    This capacitance will cause a current to flow from the AC source and the current will increase as the input frequency increases. This is called a reactive current and because it is out of phase with the input voltage there is no power loss associated with the increase in current.

    Regards

    John

  • 0 in reply to John Griffin1
    Expert 1060 points
    Hi Mr. John Griffin,
    Thanks for your valuable reply.

    Can I use 1N5408 for rectification in 400Hz application?
    I am in little bit confusion in "reactive current out of phase with input voltage". Please clarify my doubt.
    and why there is no power loss associated with the increase in current.?