15 April 2018

Single phase full converter drive

  • In single phase full converter, there are two full converters, one converter feeding the armature circuit and the other converter feeding the field circuit of a separately excited dc motor are shown in circuit diagram. 
  • For regenerative braking of the motor, the power must flow from the motor to be AC source and also this is feasible only if motor counter emf is reversed because then ea it would be negative, shown in the figure.
  • So the direction of the current can not be reversed as SCR are a unidirectional device.
  • In order that current in field winding can be reversed, the field winding must be energized through single phase full converter as shown in the figure.
For the armature converter 1,   V= Vf  =  (2Vm/∏ ) * Cos ɖ   for 0 < ɖ <  ∏

For single phase semi converter in the field circuit, the average output voltage is given by the following formula, 
           Same way for the field converter 2,   Vf   =  (2V/ ∏ ) * Cos ɖ for 0 < ɖ1  <  

Single phase full converter drives