INFORMATION AND COMMUNICATIONS UNIVERSITY
SCHOOL OF ENGINEERING
BACHELOR ELECTRICAL/ELECTRONICS ENGINEERING
POWER ELECTRONICS
FINAL EXAMINATION
Instructions to candidates
a) This Exam has two sections. Section A is compulsory but choose 3
questions in section B
b) Time allowed for this exam is three (3) hours.
c) Show your working with suitable diagrams and graphs
d) Write your answers neatly on a separate answer booklet provided
Section A (Compulsory)
Figure 1 shows a rectifier circuit
Van
Vbn
Vcn
D1
D2
D3
LOAD
Fig 1: Rectifier circuit
The rectifier in Fig.1 is operated from 460 V 50 Hz supply at secondary side and the load
resistance is R=20. Assume the source inductance is negligible, and answer the
following questions;
i.
Give a name to the circuit
(2 Marks)
ii.
Calculate the following;
(a) Form factor
(b) Ripple factor
(c) Peak inverse voltage (PIV) of each diode.
(8 Marks)
(7 Marks)
(3 Marks)
SECTION B (choose three (3) questions in this section)
1. Draw the circuit of a single phase full wave bridge rectifier with resistive
load and show its operation principles
(10 Marks)
2. Show the construction of a thyristor and explain its operation
(10 Marks)
3. Explain the principle of operation of a buck convertor
(10 Marks)
4. Explain the principle of operation of a boost convertor
(10 Marks)