Module 3B3 - Switch Mode Electronics

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Leader: Dr P.R. Palmer


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Introduce electronic power conditioning as a specific technology. Develop the mathematical methods for circuit analysis. Introduce power semiconductor devices and circuits, describing their use in a range of applications. These include rectification, linear and switch-mode power supplies, a.c. power control circuits and dc-ac inverters using pulse-width modulation.


Page Last updated 20 October 2013 by Dr Palmer

Lab Experiment

The lab experiment on the thyristor converter is undertaken in the EIT Laboratory, Inglis first floor.

LAB Sheet

The lab may be undertaken prior to the material being covered in Lecture 5. Hint: Read the lab sheet and references before presenting yourself in the Lab.

Note: Special sinewave paper is available in the EIT Lab or can be printed here.

This experiment may be adopted for your full technical writeup. Suggested extension here.

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Lecture Notes (Bingo style) are available below:





1-3 1. Diodes and Rectifier Circuits

2. Capacitor Smoothing

3. Inductor Smoothing

4. Three Phase Rectifiers

5. Thyristor Controlled Converters and Phase Control

Introduction to circuits with switching, analysys methods and recitification 3B3lec1-5.pdf Smoothing


Diode Recovery

3-4 6. MOSFET Transistors as switches

7. Bipolar Transistor switching devices

8. IGBTs

Gated power switches and circuits    
5-6 9. Basic dc-dc converter circuits

10. Bridge converters

11. Switching converters with isolation

12. Switch-mode dc to ac inverters I

Includes review of switching losses. 3B3lec9-12.pdf  
7-8 13. Switch-mode dc to ac inverters II

14. Resonant Converters I

15. Resonant Converters II

16. Applications

SVM is not in the books. 3B3lec13-15.pdf  


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Examples Papers

Paper 1 Rectifier Circuits Crib 3B3/1
Paper 2 Thyristors and transistors as switches; Converter circuits Crib 3B3/2
Paper 3 dc to dc converters; dc to ac inverters Crib 3B3/3
Paper 4 Resonant converter circuits; high side drivers Crib 3B3/4

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Exam Paper Comments

2010 Exam Paper Crib Despite clear instructions many used simplified analysis for Q1b. Q2a was a tad tough, but most did the sensible approximation (as did I originally). Overall a good example of a paper.
2009 Exam Paper Crib Good example. Q1b Some trouble with the Fourier terms.....Q4c last part - Add a snubber capacitor as in lectures.
2008 Exam Paper Crib Q1a I changed the question to give 44mA (to be nice). Q2c crib also changed. A good example of a paper.

Notes: In all cases of 'lists', where the number requested is given, the crib has sufficient for a full answer but there are often other perfectly good answers which you may prefer.

ITRW: In the real world.


The resonant dc-dc converter work assumes lossless resonance - use wO and ZO in the analysis: Take initial conditions into account by a series battery (for charged capacitors) or a parallel current source (inductors with current in them). I believe I emailed in 2010/11 that we had not completed resonant dc/dc therefore they will not arise in the exam.

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Messages 2013

I seemed to loose 'j' in my Fourier circuit analysis. Please put it back!

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Supervision Arrangements 2013

Allocation of Supervisors is here.

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Links to Interesting stuff

Simple power supplies and transformers Gives a good review
Introductory Circuits Simple but solid
Diodes Nice note on fast diodes for switched mode dcdc converters
Thyristors From one of the world's first semiconductor manufacturers
MOSFETs Patented Hexagon shaped cell since 1980s
Bipolar From one of the best!
Space Vector Modulation Nice examples of how it is really done!
Industrial RF Heating Vancouver Based! 300kW kilns
Compact Fluorescent Lamps A real enthusiast's website!
Circuit Simulation Stylish and fast simulations with lots of examples you can use to check your understanding. Sometimes the actual results are a little off as it uses some tricks for speed. So think about the results.
Circuit Simulation LtSpice Ltspice is mostly about LT's power electronic converter IC's!

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