DC-DC boost converter

Discussion in 'General Electronics Chat' started by robert.guttormson, May 18, 2011.

  1. robert.guttormson

    Thread Starter New Member

    Oct 3, 2009
    I am designing a boost converter for a motor drive that accepts DC voltage and transforms it to AC. The motor drive accepts 320V DC input. I tried following the principles of a simple boost converter but the output never converges after following all the equations. I added a more than necessary cap to smooth out any ripple. I have simulated a pulse for a particular duty cycle. As usual, I dont know why it doesnt work, read through the other threads on the forum but couldnt figure out. Any or all help is appreciated. TIA
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
    Well if you will work in CCM then

    D = (1 - 140V/320V) = 0.56
    So for F = 40KHz
    Ton = 14us
    L_min = (14us * 140V)/ ( 2 * IL) = 3mH

    So if you want to use coil 55uH you need Ton = ( L * 2*IL) /Vin_min = (55uH *0.6A)/140V = 235ns ----> F = 0.56/235ns = 2.3MHz.

    So if you change L1 =3.3mH and Ton=14.1us then you will get 320V in LTspice after 250ms

    And for DCM change L1= 680uH and Ton = 10.5us
    Last edited: May 18, 2011