In the following chopper, the duty ratio of switch S is 0.4. If the inductor and capacitor are sufficiently large to ensure continuous inductor current and ripple free capacitor voltage, the charging current (in Ampere) of the 5 V battery, under steady-state, is ________.
Consider a HVDC link which uses thyristor based line-commutated converters as shown in the figure. For a power flow of 750 MW from System 1 to System 2, the voltages at the two ends, and the current, are given by: ${V}_{1}$ =500 kV, ${V}_{2}$ =485 kV and I=1.5 kA. If the direction of power flow is to be reversed (that is, from System 2 to System 1) without changing the electrical connections, then which one of the following combinations id feasible?
The circuit shown is meant to supply a resistive load ${R}_{L}$ from two separate DC voltage sources. The switches S1 and S2 are controlled so that only one of them is ON at any instant. S1 is turned on for 0.2 ms and S2 is turned on for 0.3 ms in a 0.5 ms switching cycle time period. Assuming continuous conduction of the inductor current and negligible ripple on the capacitor voltage, the output voltage ${V}_{0}$(in Volt) across ${R}_{L}$ is ________.
A self commutating switch SW, operated at duty cycle $\delta $is used to control the load voltage as shown in the figure.
Under steady state operating conditions, the average voltage across the inductor and the capacitor respectively, are
The single-phase full-bridge voltage source inverter (VSI), shown in figure, has an output frequency of 50 Hz. It uses unipolar pulse width modulation with switching frequency of 50 kHz and modulation index of 0.7. For ${V}_{in}$= 100V DC, L=9.55 mH, C=63.66 µF, and R=5$\mathrm{\Omega}$, the amplitude of the fundamental component in the output voltage ${\mathrm{V}}_{0}$(in volt) under steady-state is_____________.
In the following circuit, the input voltage ${\mathrm{V}}_{\mathrm{in}}$ is 100$\mathrm{sin}\left(100\pi t\right)$. For 100$\pi RC$=50, the average voltage across R(in Volts) under steady-state is nearest to
A buck converter feeding a variable resistive load is shown in the figure. The switching frequency of the switch S is 100 kHz and the duty ratio is 0.6. The output voltage ${V}_{\mathit{0}}$ is 36 V. Assume that all the components are ideal, and that the output voltage is ripple-free. The value of R (in Ohm) that will make the inductor current (i_{L}) just continuous is _________.
For the switching converter shown in the following figure, assume steady-state operation. Also assume that the components are ideal, the inductor current is always positive and continuous and switching period is ${\mathrm{T}}_{\mathit{s}}$. If the voltage ${\mathrm{V}}_{\mathrm{L}}$ is as shown, the duty cycle of the switch S is _______.
In the given rectifier, the delay angle of the thyristor ${\mathrm{T}}_{1}$ measured from the positive going zero crossing of ${\mathrm{V}}_{\mathrm{s}}$ is 30°. If the input voltage ${\mathrm{V}}_{\mathrm{s}}$ is 100 sin(100πt)V, the average voltage across R (in Volt) under steady-state is _______.
Figure shows four electronic switches (i), (ii), (iii) and (iv). Which of the switches can block voltages of either polarity (applied between terminals ‘a’ and ‘b’) when the active device is in the OFF state?
A single-phase SCR based ac regulator is feeding power to a load consisting of 5 Ω resistance and 16 mH inductance. The input supply is 230 V, 50 Hz ac. The maximum firing angle at which the voltage across the device becomes zero all throughout and the rms value of current through SCR, under this operating condition, are]
The SCR in the circuit shown has a latching current of 40 mA. A gate pulse of 50 μs is applied to the SCR. The maximum value of R in Ω to ensure successful firing of the SCR is _________.
The separately excited dc motor in the figure below has a rated armature current of 20 A and a rated armature voltage of 150 V. An ideal chopper switching at 5 kHz is used to control the armature voltage. If L_{a}= 0.1 mH, R_{a}= 1$\Omega $ , neglecting armature reaction, the duty ratio of the chopper to obtain 50% of the rated torque at the rated speed and the rated field current is
Thyristor T in the figure below is initially off and is triggered with a single pulse of width 10 μs. It is given that $L=\left(\frac{100}{\mathrm{\pi}}\right)\mu \mathrm{H}$ and $C=\left(\frac{100}{\mathrm{\pi}}\right)\mu \mathrm{F}$. Assuming latching and holding currents of the thyristor are both zero and the initial charge on C is zero, T conducts for
The typical ratio of latching current to holding current in a 20 A thyristor is
Circuit turn-off time of an SCR is defined as the time
A voltage commutated chopper circuit, operated at 500Hz, is shown below.
If the maximum value of load current is 10A, then the maximum current through the main (M) and auxiliary (A) thyristors will be
A solar energy installation utilize a three – phase bridge converter to feed energy into power system through a transformer of 400V/400 V, as shown below
The energy is collected in a bank of 400 V battery and is connected to converter through a large filter choke of resistance10Ω.
The maximum current through the battery will be
The kVA rating of the input transformer is
The power electronic converter shown in the figure has a single-pole double-throw switch. The pole P of the switch is connected alternately to throws A and B. The converter shown is a
The circuit shows an ideal diode connected to a pure inductor and is connected to a purely sinusoidal 50Hz voltage source. Under ideal conditions the current waveform through the inductor will look like
Match the switch arrangements on the top row to the steady-state V-I characteristics on the lower row. The steady state operating points are shown by large black dots.
A single phase fully controlled converter bridge is used for electrical braking of a separately excited dc motor. The dc motor load is represented by an equivalent circuit as shown in the figure.
Assume that the load inductance is sufficient to ensure continuous and ripple free load current. The firing angle of the bridge for a load current of I_{0} = 10 A will be
A three-phase, 440 V, 50 Hz ac mains fed thyristor bridge is feeding a 440 V dc, 15 kW, 1500 rpm separately excited dc motor with a ripple free continuos current in the dc link under all operating conditions, Neglecting the losses, the power factor of the ac mains at half the rated speed is
In the circuit of adjacent figure the diode connects the ac source to a pure inductance L.
The diode conducts for
The circuit in the figure is a current commutated dc-dc chopper where, Th_{M} is the main SCR and Th_{AUX} is the auxiliary SCR. The load current is constant at 10 A. Th_{M} is ON. Th_{AUX }is trigged at t = 0. Th_{M} is turned OFF between
A 1:1 Pulse Transformer (PT) is used to trigger the SCR in the adjacent figure. The SCR is rated at 1.5 kV, 250 A with I_{L} = 250 mA, I_{H} = 150 mA, and I_{Gmax} = 150 mA, I_{Gmin} = 100 mA. The SCR is connected to an inductive load, where L = 150 mH in series with a small resistance and the supply voltage is 200 V dc. The forward drops of all transistors/diodes and gate-cathode junction during ON state are 1.0 V.
The resistance R should be
The minimum approximate volt-second rating of pulse transformer suitable for triggering the SCR should be : (volt-second rating is the maximum of product of the voltage and the width of the pulse that may applied)