voltage controlled capacitor????

Discussion in 'The Projects Forum' started by onlyvinod56, Jan 6, 2010.

  1. onlyvinod56

    Thread Starter Active Member

    Oct 14, 2008
    362
    1
    hello,

    not wasting the time,

    Iam designing a power factor correction circuit. (Not yet put on the PCB)
    Just paper work is going on.

    the phase angle between the voltage and current are measured in terms of a voltage.
    this voltage is compared with a preset (0 volts) to achieve 0 time difference (unity pf).

    my question is, how can i design a variable capacitance controlled by a voltage.

    any idea please...
    thankyou
     
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    How much capacitance do you need?
     
  3. rjenkins

    AAC Fanatic!

    Nov 6, 2005
    1,015
    69
    Power factor correctors typically switch banks of capacitors in & out of circuit using large contactor-style relays.

    One setup uses multiple banks of capacitors, with each bank double the value of the last.

    If you imagine a setup with eg. six banks, values 1, 2, 4, 8, 16, 32 KVAR, it's possible to set any value from 0 to 63 KVAR by controlling the contactors with the equivalent six bit binary value.

    Use a binary counter and step the value up or down depending if the capacitance needs to increase or decrease.
     
Loading...