Type B Chopper ( Class B Chopper )

  • The type B chopper works in second quadrant it means that the output voltage positive and output current negative. 
  • The load current flows through load to supply side.  
  • When chopper CH1 is switched on, the output voltage becomes zero but load current flows from load to supply side through LOAD – L – CH1 – LOAD because of back emf of the load. 
  • When chopper CH1 is switched off, the output voltage is greater than the input voltage because of stored energy of inductor. 
  • The diode D becomes forward biased and load current flows through path LOAD – L – D – Vdc – LOAD. 
  • This type chopper is called as step up chopper because the output voltage is greater than the input voltage. 
  • The application of this chopper is in the regenerative braking of DC Motor
  • The output voltage and current waveform is shown in the figure B. 
  • The diode D turns on during chopper turn off time therefore the waveform starts from TOFF time rather than TON time.

working of type b chopper
waveform of type b chopper

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