Resonant and Soft-Switching Techniques in Power Electronics

ECEN 5817 Spring 2008

Announcements, Updates, and Pertinent Material

  • Wednesday, Apr. 30: Off-campus students: You are entitled to receive passwords to all the homework solutions when you start the final. If you do not already have all the passwords, please request the list when you are ready. However, note that once you have received a password for a homework, you can not turn that homework in for credit anymore.

  • Monday, Apr. 21: Off-campus students: Please note that all course work must be submitted by Monday, May 19 at 5:00 PM MDT in order to avoid receiving an Incomplete in the class. This means if you want the full 5 days to complete your final, you must request the final by Wednesday, May 14.

  • Saturday, Mar. 15: ON-CAMPUS STUDENTS: PLEASE CHECK YOUR colorado.edu EMAIL ACCOUNT FOR IMPORTANT INFORMATION CONCERNING THE MIDTERM EXAM!
  • Thursday, Mar. 13: CAETE students: The slide giving lecture number for lecture 24 on the CU Anywhere website is incorrect. The slide says lecture 23, but it is in fact lecture 24.
  • Sunday, Mar. 9: Part (b) of Problem 1 of HW #7 has been updated. Find an expression in terms of normalized output voltage M = V/(nVg), not V/Vg.
  • Tuesday, Mar. 4: Problem 1 of HW #6 shows plots of D2 diode voltage and current during diode turn-off transition of the forward converter. The ringing of diode voltage during t > t3 has not been drawn to scale, - the amplitude of the ringing should be larger than shown in the figure. In particular, the ringing waveform should climb back to at least the value at t = t3 (0 V). The figure has been updated slightly to show the zero voltage line, but the magnitude of the ringing is till ont to scale.
  • Tuesday, Mar. 4: A student has pointed out that there is an error in HW #2 solution to Problem 19.3. The solution for the conversion ratio M is missing a power of 2, i.e. solution says M = sqrt(1 + Qe^2 * (F - 1/F)), the answer should be M = sqrt(1 + Qe^2 * (1/F - F)^2). If you got points marked off for this, please bring your homework to me (or fax / scan and email the relevant page) and we will replace those points.
  • Tuesday, Feb. 26: Problem 1 of HW #5 concerns a parallel resonant inverter operated with duty cycle control. The problem refers to Fig. 9(c) of the packet 2 dynamics course notes. These notes can be found on the course website under "Materials", "Materials on ac (envelope) modeling of resonant converters". Fig. 9(c) is simply a plot of the switch node voltage, vs(t) under duty cycle control. We have also discussed duty cycle control in class.
  • Wednesday, Feb. 13: I need to reschedule office hours for Thursday, 2/21. For on-campus students, instead of 12:00 - 2:00, the hours will be 1:00 - 2:00 and 3:00 - 4:00 (telephone office hours are from 2:00 - 3:00, on-campus students can come at that time although priority given to off-campus students).
  • Tuesday, Feb. 12: A link to PDF version of AC modeling slides created by Professor Erickson has been added to the AC modeling section of the Materials section of the website. These are excellent slides and may be a good reference to have during lectures. I do not necessarily use the slides myself when I am speaking because it helps me to re-write / draw the material, however the lectures follow the slides very closely.
  • Tuesday, Feb. 12: HW #4 due date has been moved to Monday, Feb. 18. HW #5 will then be due on Friday, Feb. 29.
  • Wednesday, Feb. 6: Correction to Problem 19.9 in the book. Part (a) asks you to derive expressions for Voc and Isc in terms of the quantity Rinfinity. The expression for Rinfinity should be under a square root, i.e. Rinfinity = sqrt(L/(Cs||Cp)).
  • Thursday, Jan. 24: Reminder that Homework #1 is due tomorrow for on-campus students. CAETE students, please submit your homework according to the schedule which you have set for yourself. Also, due to popular request, an announcement was made in Lecture #3 lifting the ban on scanned and e-mailed homework as long it meets certain requirements. All problems should be scanned into ONE PDF file for the entire assignment. The file should be easy to read (200 - 300 dpi), easy to print, and should be a reasonable size.
  • Tuesday, Jan. 22: CDs containing lectures from Professor Erickson's Spring '06 course have been mailed to off-campus students. These CDs will be distributed to on-campus students in class on Wednesday, Jan. 23. If you cannot make class on Wednesday, I will have your CDs and you can either pick up during my office hours on Thursday or I will bring them to class on Friday. Please note the Tegrity sessions will only play on Windows with Internet Explorer.
    I plan on indicating for each lecture(s) of this year the equivalent lecture(s) from Spr. 06. This will make it easy if you choose to watch those lectures to stay in synch with this years class if we should run at a slightly different pace. I will also indicate if there is any new material for this year not covered in Spr. 06 so you will know to watch / attend that particular lecture this year. Similarly, any material covered in Spr. 06 but not covered this year will not show up as an equivalent lecture so you will know you can skip it.

Update

This course is offered in alternate spring semesters. It is being offered in Spring 2008. Instructors: Professor Robert Erickson, Mariko Shirazi. It is one of the three courses required for the Professional Certificate in Power Electronics.

The required prerequisite for the course is ECEN 5797 Introduction to Power Electronics. Note that ECEN 5807 is not prerequisite. This course supersedes the course previously called Power Electronics 3.

The course is offered both to regular on-campus students and also to off-campus students via CAETE. Students registered through CAETE can receive lectures via videotape or DVD, web-based streaming video, or live TV. Further details of the course policies, including procedures for off-campus students, are listed on the Vitals page.

The course includes a detailed study of the mechanisms of switching loss, hard switching, and soft switching. Both traditional resonant converters and up-to-date nonresonant approaches to zero-voltage soft switching are included. Applications emphasized include dc-dc converters for computer power and portable applications, and dc-ac inverters for gas discharge lighting. Analysis approaches include steady-state analysis in the frequency domain (Bode plot) and time domain (state plane analysis), and ac modeling using the averaged switch modeling and the phasor transform methods. Topics added to the course in 2006 are: small-signal modeling of resonant converter transfer functions, and optimization of system efficiency at both full- and light-load conditions. A detailed syllabus is attached.