GATE EE

Choppers and Commutation Techniques

Power Electronics

(Past Years Questions)

Marks 1

More
A buck converter, as shown in Figure $$(a)$$ below, is working in steady state. The output voltage and the inductor curr...
GATE EE 2016 Set 1
In the following chopper, the duty ratio of switch $$S$$ is $$0.4.$$ If the inductor and capacitor are sufficiently larg...
GATE EE 2015 Set 1
A step-up chopper is used to feed a load at $$400$$ $$V$$ $$dc$$ from a $$250$$ $$V$$ $$dc$$ source. The inductor curren...
GATE EE 2014 Set 2
The power electronic converter shown in the figure has a single-pole double-throw switch. The pole $$P$$ of the switch i...
GATE EE 2010
A step down chopper is operated in the continuous conduction mode in steady state with a constant duty ratio $$D.$$ If $...
GATE EE 2002
In a thyristor $$dc$$ chopper which type of commutation results in best performance?
GATE EE 1996
A $$dc$$ to $$dc$$ transistor chopper supplied from a fixed voltage $$dc$$ source feeds a fixed resistive-inductive load...
GATE EE 1995
Consider the chopper circuit of figure. The chopper operates at $$400$$ $$Hz$$ and $$50$$% duty cycle. The load current...
GATE EE 1995
Match the following List $$-$$ $${\rm I}$$ $$A.$$ Commutation $$B.$$ $$V$$ $$-$$ Curves $$C.$$ Free wheeling diode $$D.$...
GATE EE 1994
A chopper operating at a fixed frequency is feeding an $$R$$-$$L$$ load. As the duty ratio of the chopper is increased f...
GATE EE 1993

Marks 2

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The figure shows two buck converters connected in parallel. The common input dc voltage for the converters has a value o...
GATE EE 2018
A dc to dc converter shown in the figure is charging a battery bank, B2 whose voltage is constant at 150 V. B1 is anothe...
GATE EE 2018
In the circuit shown all elements are ideal and the switch $$S$$ is operated at $$10$$ $$kHz$$ and $$60$$% duty ratio. T...
GATE EE 2017 Set 2
The input voltage $${V_{DC}}$$ of the buck-boost converter shown below varies from $$32$$ $$V$$ to $$72$$ $$V.$$ Assume ...
GATE EE 2017 Set 1
For the switching converter shown in the following figure, assume steady-state operation. Also assume that the component...
GATE EE 2015 Set 2
A buck converter feeding a variable resistive load is shown in the figure. The switching frequency of the switch $$S$$ i...
GATE EE 2015 Set 1
The circuit shown is meant to supply a resistive load $${R_L}$$ from two separate $$DC$$ voltage sources. The switches $...
GATE EE 2015 Set 1
A self commutating switch $$SW,$$ operated at duty cycle $$\delta $$ is used to control the load voltage as shown in the...
GATE EE 2015 Set 1
Figure (i) shows the circuit diagram of a chopper. The switch $$S$$ in the circuit in figure (i) is switched such that t...
GATE EE 2014 Set 1
In the figure shown below, the chopper feeds a resistive load from a battery source. $$MOSFET$$ $$Q$$ is switched at $$2...
GATE EE 2013
In the figure shown below, the chopper feeds a resistive load from a battery source. $$MOSFET$$ $$Q$$ is switched at $$2...
GATE EE 2013
In the circuit shown, an ideal switch $$S$$ is operated at $$100$$ $$kHz$$ with a duty ratio of $$50%$$. Given that $$\D...
GATE EE 2012
A voltage commutated chopper circuit, operated at $$500Hz,$$ is shown below. If the maximum value of load current is $$1...
GATE EE 2011
The L-C circuit shown in the figure has an inductance $$L=1mH$$ and a capacitance $$C = 10\mu F.$$ The initial current t...
GATE EE 2010
The L-C circuit shown in the figure has an inductance $$L=1mH$$ and a capacitance $$C = 10\mu F.$$ The $$L$$-$$C$$ circu...
GATE EE 2010
In the chopper circuit shown, the main thyristor $$\left( {{T_M}} \right)$$ is operated at a duty ratio of $$0.8$$ which...
GATE EE 2009
In the circuit shown in the figure, the switch is operated at a duty cycle of $$0.5.$$ A large capacitor current is conn...
GATE EE 2008
The circuit in the figure is current commutated $$dc$$ $$-$$ $$dc$$ chopper where, $$T{h_M}$$ is the main $$SCR$$ and $$...
GATE EE 2007
A voltage commutated chopper operating at $$1$$ $$kHz$$ is used to control the speed of $$dc$$ motor as shown in figure....
GATE EE 2006
A voltage commutated chopper operating at $$1$$ $$kHz$$ is used to control the speed of $$dc$$ motor as shown in figure....
GATE EE 2006
A voltage commutation circuit is shown in figure. If the turn off time of the $$SCR$$$$s$$ is $$50$$ $$\mu \sec $$ and ...
GATE EE 2006
The given figure shows a step $$-$$ down chopper switched at $$1$$ $$KHz$$ with a duty ratio $$D = 0.5.$$ The peak - pea...
GATE EE 2005
Figure shows a chopper operating from a $$100$$ $$V$$ $$dc$$ input. The duty ratio of the main switch $$S$$ is $$0.8.$$ ...
GATE EE 2004
Figure shows a chopper. The device $${S_1}$$ is the main switching device. $${S_2}$$ is the auxiliary commutation device...
GATE EE 2004
A chopper is employed to charge a battery as shown in figure. The charging current is $$5A$$. The duty ratio is $$0.2.$$...
GATE EE 2003
In the chopper circuit shown in fig the input $$dc$$ voltage has a constant value $${{V_s}}$$. the output voltage $${{V_...
GATE EE 2002
A step down chopper operates from a $$dc$$ voltage source $${V_s}$$ feeds a $$dc$$ motor armature with a back $$e.m.f$$ ...
GATE EE 2000

Marks 5

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In fig, the ideal switch $$S$$ is switched on and off with a switching frequency $$f = 10 kHz.$$ The switching time peri...
GATE EE 2002
A voltage commutated thyristor chopper circuit is shown in fig. The chopper is operated at $$500$$ $$Hz$$ with $$50\% $$...
GATE EE 2001
A $$dc$$ motor with armature resistance $${R_a}$$ is fed from a step down chopper in the continuous mode, and operates a...
GATE EE 2000

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