Lecture 1 August 27 2012 Introduction to Power Electronics ECEN 4797 5797 Robert W Erickson University of Colorado Boulder Fall 2012 1 Introduction to Power Electronics ECEN 4797 5797 Instructor Prof Bob Erickson Of ce ECOT 356 Telephone 303 492 7003 Email rwe colorado edu Of ce hours MW 3 00 4 00 pm Telephone of ce hours M 3 00 4 00 pm Course web site http ece colorado edu ecen5797 Includes lecture slides handouts homework assignments links to online lecture les Textbook Erickson and Maksimovic Fundamentals of Power Electronics second edition Springer ISBN 0 7923 7270 0 Prerequisite A 3 4 semester sequence of undergraduate EE circuits and electronics courses at Univ of Colorado ECEN 3250 2 Coursework in Power Electronics at the University of Colorado Power electronics courses ECEN 4797 5797 this course Intro to power electronics Fall ECEN 5807 Modeling and Control of Power Electronics Systems Alt Spring semesters including S 13 ECEN 5817 Resonant and Soft Switching Techniques in Power Electronics Alt Spring semesters including S 14 ECEN 4517 5517 Power Electronics Laboratory Spring Professional Certi cate in Power Electronics ECEN 5797 5807 and 5817 Formats for this course On campus for senior or graduate credit Web based lectures recorded with ECHO 360 system with viewing through the Flash viewer For technical help contact help cuengineeringonline colorado edu CAETE 3 Grading Homework Due at beginning of class on date listed on Lecture Schedule web page Submit online via D2L dropbox late homework not accepted Homework counts 50 of grade You may speak with others about the homework but turn in your own work Homework and exam problems of additional depth and complexity for those earning graduate credit separately graded Exams Midterm exam one week take home exam 17 of grade Final exam ve day take home exam 33 of grade See course schedule page for dates See course vitals page for details 4 Desire 2 Learn D2L Site learn colorado edu Log on with your campus IdentiKey Dropbox for submission of homework and exams Scan save as pdf then upload to the D2L dropbox For on campus students a scanner is available within the SRC Automatic deadline at beginning of class A log of your grades for all assignments When grading is complete your grade will appear online Running total of your overall course grade Grader will post comments and annotations online Homework solutions Posted within D2L after submission deadline Student discussion forum You can post questions and discussions with your classmates Normally questions will not be answered by Prof Erickson Posting of homework solutions in the forum is prohibited 5 Off campus students Viewing of lectures Lectures are normally available online by the end of the day of the oncampus lecture Assignments Use the D2L site to upload your pdf le same as for on campus students Generally by Friday the lectures will nish covering the material needed for the homework assignment due the following Friday So you can work the homework over the weekend Professor Erickson will be available for telephone of ce hours on Monday afternoon to answer any questions Check out the D2L student forums Due dates are the same as for the on campus students Educational Of cers Not needed See course vitals page Link to academic calendar for CAETE students including add drop deadlines 6 Key dates Drop deadlines September 12 last day to drop the course and receive full tuition refund with no W grade appearing on transcript October 10 last day to drop the course without petitioning the Dean s of ce Tentative exam dates Midterm exam 1 week take home exam Available through D2L on Oct 19 due on Oct 26 Final exam Four day take home exam Available through D2L on Dec 14 due on Dec 18 Grades assigned in May appear on your permanent university transcript Campus holidays Labor day Sept 3 Fall break Thanksgiving holiday Nov 19 23 7 Chapter 1 Introduction 1 1 Introduction to power processing 1 2 Some applications of power electronics 1 3 Elements of power electronics Summary of the course 7 1 1 Introduction to Power Processing Power input Switching converter Power output Control input Dc dc conversion Ac dc recti cation Dc ac inversion Change and control voltage magnitude Possibly control dc voltage ac current Produce sinusoid of controllable magnitude and frequency Ac ac cycloconversion Change and control voltage magnitude and frequency 8 Control is invariably required Power input Switching converter Power output Control input feedforward feedback Controller reference 9 High ef ciency is essential 1 Pout Pin 0 8 1 1 Ploss Pin Pout Pout 0 6 High ef ciency leads to low power loss within converter Small size and reliable operation is then feasible Ef ciency is a good measure of converter performance 0 4 0 2 0 0 5 1 Ploss Pout 10 A high ef ciency converter Pin Converter Pout A goal of current converter technology is to construct converters of small size and weight which process substantial power at high ef ciency 11 1 5 Devices available to the circuit designer DT Resistors Capacitors Magnetics T s s Linearmode Switched mode Semiconductor devices 12 Devices available to the circuit designer DT Resistors Capacitors Magnetics Signal processing avoid magnetics 13 T s s Linearmode Switched mode Semiconductor devices Devices available to the circuit designer DT Resistors Capacitors Magnetics T s s Linearmode Switched mode Semiconductor devices Power processing avoid lossy elements 14 Power loss in an ideal switch Switch closed v t 0 Switch open i t 0 In either event p t v t i t 0 Ideal switch consumes zero power 15 v t i t A simple dc dc converter example I 10A Vg 100V Dc dc converter R 5 V 50V Input source 100V Output load 50V 10A 500W How can this converter be realized 16 Dissipative realization Resistive voltage divider I 10A Vg 100V 50V Ploss 500W R 5 V 50V Pout 500W Pin 1000W 17 Dissipative realization Series pass regulator transistor operates in active region I 10A 50V Vg 100V linear amplifier and base driver Vref R 5 V 50V Ploss 500W Pout 500W Pin 1000W 18 Use of a SPDT switch I 10 A 1 Vg 100 V 2 vs t R vs t Vg Vs DVg switch position DTs 0 1 D Ts t 1 2 1 19 v t 50 V The switch changes the dc voltage level vs t Vg Vs DVg switch position DTs 0 1 D Ts t 1 2 1 D switch duty cycle 0 D 1 Ts switching period fs switching frequency 1 Ts DC component of vs t average value Vs 1 Ts Ts vs t dt DVg 0 20 Addition of low pass lter Addition of ideally lossless L C low pass lter for removal of switching