good luck

Dr. Özgür ÜSTÜN 16/11/2005
POWER ELECTRONIC CIRCUITS
2005-2006 Fall
Midterm Exam
Questions:
1. A highly inductive load is to be supplied from a single phase full-wave diode
rectifier. The load requires 12 A at 150V. The ac supply is from the 240V mains.
Produce the design details of the centre-tap and bridge rectifier circuits and
compare the two designs (calculate the PRV of diodes, the transformer kVA, the
transformer ratio, the transformer primary current, the mean and rms values of
diode currents and the diode losses for both configuration). Assume that the diode
drop is fixed at 0.7 V.
2. In the circuit shown in figure determine the load current expression and calculate
the mean load voltage and current values. And find the mean value of the current
flowing through freewheeling diode. Sketch the waveform of the inductance
voltage.
D1
R=3Ω
220V
50Hz
~
D2
+
L=0.01H
E=100V
3. A single phase, controlled bridge rectifier is supplying a resistive load of 20Ω from
a 220V, 50Hz AC source. The firing angle of thyristors is 60°.
a. Draw the circuit schema
b. Calculate the mean value of the load voltage and load current
c. Calculate the form factor (FF) and ripple factor (RF) of the circuit
d. Calculate the input power factor
4. A 3-phase half-wave controlled rectifier is to supply a pure resistive load.
a. Draw the circuit schema
b. Sketch the waveforms of load voltage, load current, thyristor currents
c. Find the mean value of load voltage
d. Find the input power factor of the circuit
good luck

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