GATE EE 2004 | Choppers and Commutation Techniques Question 33 | Power Electronics

GATE EE 2004

MCQ (Single Correct Answer)

-0.6

Figure shows a chopper. The device $${S_1}$$ is the main switching device. $${S_2}$$ is the auxiliary commutation device. $${S_1}$$ is rated for $$400V, 60A.$$ $${S_2}$$ is rated for $$400V, 30 A.$$ the load current is $$20$$ $$A.$$ The main device operates with a duty ratio of $$0.5.$$ The peak current through $${S_1}$$ is GATE EE 2004 Power Electronics - Choppers and Commutation Techniques Question 31 English

GATE EE 2004 Power Electronics - Choppers and Commutation Techniques Question 31 English

$$10$$ $$A$$

$$20$$ $$A$$

$$30$$ $$A$$

$$40$$ $$A$$

GATE EE 2003

MCQ (Single Correct Answer)

-0.6

A chopper is employed to charge a battery as shown in figure. The charging current is $$5A$$. The duty ratio is $$0.2.$$ The chopper output voltage is also shown in figure. The peak to peak ripple current in the charging current is GATE EE 2003 Power Electronics - Choppers and Commutation Techniques Question 33 English

GATE EE 2003 Power Electronics - Choppers and Commutation Techniques Question 33 English

$$0.48$$ $$A$$

$$1.2$$ $$A$$

$$2.4$$ $$A$$

$$1$$ $$A$$

GATE EE 2002

MCQ (Single Correct Answer)

-0.6

In the chopper circuit shown in fig the input $$dc$$ voltage has a constant value $${{V_s}}$$. the output voltage $${{V_0}}$$ is assumed ripple free. The switch $$S$$ is operated with a switching time period $$T$$ and a duty ratio $$D.$$ What is the value of $$D$$ at the boundary of continuous and discontinuous conduction of the inductor current $${i_L}$$? GATE EE 2002 Power Electronics - Choppers and Commutation Techniques Question 34 English

GATE EE 2002 Power Electronics - Choppers and Commutation Techniques Question 34 English

$$D = 1 - {{{V_s}} \over {{V_0}}}$$

$$D = {{2L} \over {RT}}$$

$$D = 1 - {{2L} \over {RT}}$$

$$D = {{RT} \over L}$$

GATE EE 2000

MCQ (Single Correct Answer)

-0.6

A step down chopper operates from a $$dc$$ voltage source $${V_s}$$ feeds a $$dc$$ motor armature with a back $$e.m.f$$ $$\,\,{E_b}.$$ From oscilloscope traces, it is found that the current increases for time $${t_r}$$ falls to zero over time $${t_f},$$ and remains zero for time $${t_0}$$ in every chopping cycle, then the average $$dc$$ voltage across the freewheeling diode is

$${{{V_s}\,{t_r}} \over {\left( {{t_r} + {t_f} + {t_0}} \right)}}$$

$${{\left( {{V_s}\,{t_r} + {E_b}\,{t_f}} \right)} \over {\left( {{t_r} + {t_f} + {t_0}} \right)}}$$

$${{\left( {{V_s}\,{t_r} + {E_b}\,{t_0}} \right)} \over {\left( {{t_r} + {t_f} + {t_0}} \right)}}$$

$${{{V_s}\,{t_r} + {E_b}\left[ {{t_f} + {t_0}} \right]} \over {\left( {{t_r} + {t_f} + {t_0}} \right)}}$$