Electrical Revolution: Type E Chopper ( Class E Chopper )

The type E chopper is a four quadrant chopper.
The type E chopper is parallel combination of two type C chopper.
The combination of chopper CH1, chopper CH2, diode D1 and diode D2 makes one type C chopper and other is made from chopper CH3, chopper CH4, diode D3 and diode D4.

Working

When chopper CH1 and chopper CH2 are switched on, the load current flows through (+)V_dc – A – CH1 – LOAD – G – CH2 – K – V_dc( – ).
The output voltage and current both are positive therefore it is first quadrant operation.

When chopper CH3 and chopper CH4 are switched off, the stored energy of inductor dissipates through G – LOAD – F –D1 – (+)V_dc– V_dc( – ) – L – D2 – H – G.
The output voltage is positive but output current negative during that period therefore it is second quadrant operation.

When chopper CH3 and chopper CH4 are switched on, the load current flows through (+)V_dc – C – CH3 – G – LOAD – F – E – CH4 – V_dc( – ).
The output voltage and current both are negative therefore it is third quadrant operation.

When chopper CH1 and chopper CH2 are switched off, the stored energy of inductor dissipates through F – LOAD – G – H – D3 – D –(+)V_dc– V_dc( – ) – D4 – F.
The output voltage is negative but output current is positive during this period therefore it is fourth quadrant chopper operation.
The DC supply is short circuited if chopper CH1 and CH4 or chopper CH2 and CH3 is simultaneously switched on.
When the chopper works in first and third quadrant, the output voltage is always less than the input voltage resulting it is step down type chopper.
Similarly when the chopper works in second and fourth quadrant, the output voltage is always greater than the input voltage resulting it is step up chopper.