Advanced modeling and control topics in power electronics, and power factor corrected supplies. Averaged switch modeling of converters, computer simulation, ac modeling of the discontinuous conduction mode, the current programmed mode, null double injection techniques in linear circuits, input filter design, harmonics in power systems, and low-harmonic rectifiers.
Prerequisite: ECEN 5797 Introduction to Power Electronics
Required Textbook: Erickson and Maksimovic, Fundamentals of Power Electronics, 2nd edition, Springer Science+Business (2000), ISBN 0-7923-7270-0. Can be ordered from the University of Colorado bookstore (same text as ECEN 5797).
Software requirements: internet access is required. A Spice simulator and MATLAB/Simulink are required:
- LTspice is a recommended free Spice simulator. Other Spice simulators are acceptable, but the instructor may not be able to provide any tool-specific support.
- MATLAB/Simulink are available to on-campus students in all computer labs, including the Power Lab and Circuits Lab computers; contact the instructor if you need access to these labs. Off-campus students are entitled to purchase student versions of the required MATLAB/Simulink components:
- MATLAB & Simulink Student Version (currently version R2010a): $99
- Simulink Control Design (an add-on package): $29
Syllabus
Introduction
Averaged switch modeling and simulation
- Section 7.4 and Appendix B
- Deriving averaged small-signal models of converters by averaging only the switching elements
- Objectives of simulation
- Simulation of converter small-signal behavior using averaged switch models
Techniques of Design-Oriented Analysis, with Application to Switching Converters
- Middlebrook's Extra Element Theorem
- ( Appendix C)
- Use of null double injection techniques to find how addition of an element changes a transfer function.
- Input Filter Design
- Chapter 10
- How the addition of an input filter disrupts the loop gain of a switching regulator
- How to design an input filter having adequate damping, so that the input filter does not change the loop gain
- The n-Extra Element Theorem
- Supplementary notes posted on the web site. Also, Section 8.1.8 will be covered.
- An extension of the extra element theorem that allows exact expressions for complex transfer functions to be written "by inspection."
- Middlebrook's Feedback Theorem
- Supplementary notes posted on web site
- Analysis of feedback circuits using null double injection techniques
Dynamic modeling and simulation of converters operating in discontinuous conduction mode
- Chapter 11 and Appendix B
- Equivalent circuit modeling of converters operating in the discontinuous conduction mode, using averaged switch modeling
- How changing the operating mode leads to substantial changes in small-signal transfer functions
Introduction to sampled-data modeling
- Supplementary notes posted on web site
- Sampled-data small-signal modeling
- Pulse-width modulator as a sampler, equivalent hold
- Application of the sampled-data model to dicontinuous conduction mode
Current Programmed Control
- Chapter 12 and Appendix B
- Introduction to this very popular technique for controlling switching converters
- Basic circuitry and slope compensation
- Averaged switch modeling
- Sampled-data modeling of current programmed converters (Supplementary notes posted on the web site)
- Detailed small-signal analysis
- Simulation
- Effects of current mode control on basic transfer functions
Introduction to Digital Control of Switching Converters
- Supplementary notes posted on the web site
- Digital realization of the basic control loop
- Discrete-time converter model
- Examples of discrete-time compensator design
Modern Rectifiers
- Power and Harmonics in Nonsinusoidal Systems: Chapter 16
- Pulse-Width Modulated Rectfiers: Chapter 18
- Modeling, analysis, and control of low-harmonic rectifiers
- Boost, flyback, and other topologies for controlling the input current waveform of an ac-dc rectifier
- Average-current, peak-current-mode, critical conduction mode, and nonlinear carrier control techniques
- Determination of rms currents, and comparison of performances of popular topologies
- System considerations. Modelling losses. Simulation.
One midterm exam and one final exam. Weekly homework assignments.