9 April 2017

Function of Freewheeling Diode

  • The diode is connected across load in the controlled or uncontrolled converter circuit. This diode is called as freewheeling diode or flywheel diode. 
  • The freewheeling diode is connected across R – L load in the half controlled rectifier circuit as shown in the figure A. 
< Img src = ' freewheeling-diode.png' alt = ' free wheeling diode '/>
  • As the SCR T1 is turned on during positive half cycle of alternating supply, the load current flows through load.
  • The energy stored in the inductor due to current passes through it. 
  • The stored energy of the load dissipates through freewheeling diode during negative half cycle of the alternating supply. 
  • If there is no freewheel diode, the stored energy of load back to the input supply.

Function of Freewheeling diode

  • It improves input as well as system power factor.
  • The load voltage polarity does not change.
< Img src = ' freewheeling-diode-waveforms.png' alt = ' waveforms of freewheeling diode' />