EE 486 Power Electronics Final Exam Coverage Prof. Ali Mehrizi-Sani

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1 EE 486 Power Electronics Final Exam Coverage Prof. Ali Mehrizi-Sani School of Electrical Engineering and Computer Science April 26, 2012

2 Illusions 2 of 18

3 Final Exam Coverage All Material Covered During Semester Closed book, no notes. Nontrivial equations will be provided if required. Textbook (Daniel Hart) Course Notes Course notes and the text complement each other. There are material covered in lectures that are not in the text. Homeworks All solutions are posted (Homework 10 solution will be posted on Wed). Homeworks are marked and returned. As a reminder, you have access to all material from 2012, including tests, exams, homeworks, and their solutions. 3 of 18

4 Chapters 1 and 2: Review Introductory Slides Basic Concepts Linear voltage regulator vs. switched-mode converters Efficiency Real, reactive, and complex power Average and instantaneous power Fourier series (equations will be given) RMS and average value calculation 4 of 18

5 5 of 18 Chapter 6: DC-DC Converters Sections 6.1,.2,.3,.5,.6,.7,.8,.10, and.11 IVSB <v L (t)> = 0 CCB <i C (t)> = 0 SRA i L (t) = I L, v C (t) = V C Calculating ΔI L and ΔV C Calculating M(D) Drawing Steady-State Waveforms Buck Boost Buck-Boost All other topologies

6 6 of 18 Chapter 6: Nonideal DC-DC Converters Nonideal Voltage Conversion Ratio R L R ON R D and V D ESR, r c VI characteristic for different power electronics elements: diode and MOSFET/IGBT/BJT

7 Chapter 6: Discontinuous Conduction Boundary of CCM and DCM Calculation of M(D) in DCM Applying IVSB and CCB for Three Operating States Q on, D off Q off, D on Q off, D off Small Ripple Approximation If DCM is because of inductor (diode) current, SRA is not valid for I L, but is still valid for V C 7 of 18

8 Steps for Solving a Converter Draw subcircuits for subintervals 0 < t DT and DT < t T Determine v L (t) (or v L,i (t) if there are multiple inductors) and i C (t) (or i C,i (t) if there are multiple capacitors) for each subinterval Write v L,i (t) in terms of capacitors (and output) and input voltage Write i C (t) in terms of inductor currents Apply IVSB to each v L,i (t) and CCB to each i C,i (t) Simplify and solve for V o in terms of V s 8 of 18

9 9 of 18 Chapter 7: DC Power Supplies Sections 7.1,.2,.3,.4,.5,.6,.7,.9, and.10 Transformer Model No IVSB on transformer itself (even though it looks like two inductors) Flyback Converter All figures are from Hart.

10 Chapter 7: DC Power Supplies Forward Converter Full-Bridge Converter and other converters that are in the book Push-pull Double-ended forward But not current-fed 10 of 18

11 11 of 18 Chapter 8: Inverters Sections 8.1,.2,.3,.4,.5,.7,.8,.9,.10,.11,.12,.15 Square-Wave Operation Amplitude and Harmonic Control (delay angle)

12 12 of 18 Chapter 8: Inverters Voltage and Current Waveforms Half-Bridge Inverter Multilevel Inverters

13 Chapter 8: Inverters Pulse-Width Modulation Unipolar and bipolar switching m f and m a Three-Phase Inverters Three legs 120 degrees apart 13 of 18

14 14 of 18 Chapter 3: Half-Wave Rectifiers Sections 3.1,.2,.3,.8, and.9 Resistive Load Inductive Load Capacitor Filter Controlled Rectifiers

15 Chapter 4: Full-Wave Rectifiers Sections 4.1,.2,.3,.4, and.5 Only lectures Single-Phase Resistive Load Inductive Load RLE Load Controlled Rectifiers Inverter Mode of Operation With \alpha > 90, V dc < 0 Three-Phase Rectifiers 15 of 18

16 Chapter 5: AC-AC Converters Sections 5.1 and.2 Very application specific Only lectures AC Voltage Controllers Superposition of two rectifiers Matrix Converters Cycloconverters A rectifier with changing \alpha V o = K cos(α(t)) Back-to-Back AC-DC and DC-AC 16 of 18

17 17 of 18 Bigger Picture Buck-boost--ness is in the eye of the beholder. An inverter (DC-AC) is essentially a DC-DC converter with slowly varying duty cycle. Variations of d(t) much slower than the switching frequency An AC voltage controller (AC-AC) is essentially a rectifier with slowly varying delay angle α. Variations of α(t) much slower than input frequency Ultimately, DC-DC and AC-AC can be thought of as controllable transformers. Can change effective resistance (impedance) seen by the source (utility)

18 Good Luck See you in EE525! Questions later? In Person: EME of 18

Chapter 6: Converter circuits

Chapter 6: Converter circuits Chapter 6. Converter Circuits 6.1. Circuit manipulations 6.2. A short list of converters 6.3. Transformer isolation 6.4. Converter evaluation and design 6.5. Summary of key points Where do the boost, buck-boost,