ENGINEERING TRIPOS PART IIA - 2010/2011

Module 3B3 - Switch Mode Electronics

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Leader: Dr P.R. Palmer

AIMS

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.

Syllabus

Page Last updated 24 March 2011 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.

Lectures

Lecture Notes (Bingo style) are available below:

Weeks	Topic	Comments	Notes	Video
1-2	1. Diodes and Rectifier Circuits 2. Capacitor Smoothing 3. Inductor Smoothing and Filters 4. Three Phase Rectifiers	Introduction to circuit methods and principles	3B3lec1-4.pdf	Smoothing
3-4	5. Thyristor Circuits I 6. Thyristor Circuits II 7. MOSFET Transistors as switches 8. Bipolar Transistor switching devices	Gated power switches and circuits	3B3lec5-8.pdf	ac-ac Control
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. None (Demos in lectures instead)	SVM is not in the books.	3B3lec13-15.pdf

Acknowledgements

Dr R.A. MacMahon for E2 notes (used for lectures 1-12)

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

Exam Paper Reviews

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.
2003	Sample Paper	Crib	Good example, except SVM didn't appear (it's common now ITRW).

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.

Hint:

The resonant dc-dc converter work assumes lossless resonance - use w_O and Z_O 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.

Messages

The half bridge circuit (Page 18) is also found on Page 20. Square wave inverters are met on Pages 31&32&36 under 'overmodulation'. The Fourier series for a squarewave can be found in the Maths Databook.

Supervision Arrangements 2010

Rota is here.

Links to Interesting stuff

Simple power supplies and transformers	http://www.plitron.com/pages/technote.htm	Gives a good review
Introductory Circuits	http://www.allaboutcircuits.com/	Simple but solid
Diodes	http://www.national.com/an/AN/AN-557.pdf	Nice note on fast diodes for switched mode dcdc converters
Thyristors	http://www.westcode.com/ftoc.htm	From one of the world's first semiconductor manufacturers
MOSFETs	http://www.irf.com/product-info/hexfet/	Patented Hexagon shaped cell since 1980s
Bipolar	http://www.st.com/	From one of the best!
Space Vector Modulation	http://www.infineon.com	Nice examples of how it is really done!
Industrial RF Heating	http://www.heatwave.com/technology/overview.htm	Vancouver Based! 300kW kilns
Compact Fluorescent Lamps	http://pavouk.org/hw/lamp/en_index.html	A real enthusiast's website!
Circuit Simulation	http://www.powersimtech.com/download.html	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.