Homework
assignments for EE 442 and ECG 642 Power Electronics, Fall 2022
Homework
guidelines are found here.
Course projects - due Monday, November 21 (email to me at r.jacob.baker@unlv.edu before 4 PM). I will grade them with you in person so that I can both look at the report, do simulations with you, and ask you questions to see if you understand what you are doing.
Design a switching power supply that takes an AC input on Line and Neutral ranging from 100V to 130V at 60 Hz and generates a 5V output at up to 1A for USB charging. Show, in your report, how you connect your circuit to the USB pins (assume USB 2.0 pins, that is, GND, D+, D-, and VBUS).
Your design should be a board level design for implementation on a printed circuit board. Try to estimate the size of the board. Note that you should use real components that you can buy. For example, the transformer should be one that you identify from, for example, Digikey or Mouser. You will need to figure out how to model it (this is something you should understand). You can also use the library components built-in to LTspice but you will need corresponding data sheets both to estimate the size and for the electrical characterisitics in your design.
Your report should include: your design considerations and a discussion of trade-offs, characterizations with different AC input voltages, temperatures and loads (e.g. no current, 100 mA, 1 A), and an estimate for the size of your design (again, the size of the printed circuit board). Concise plots and tables summarizing your design should be included in your report as well as discussion of the design's weaknesses and where future work should focus.
Do not simply put a bunch of pictures into a file of schematics and simulation results and then turn it in as your report. You will get a failing grade. I need to see that you understand what you are doing, the trade-offs, and can answer my questions about your work.
HW#8 due Monday, October 31, 1) design a 100 kHz oscillator with am output amplitude of 0 to 5V and a duty cycle of 95%, 2) using this oscillator design a 0 to 4 V ramp waveform generator. Assume the power supply is 5V and simulate your designs to show functionality. Your designs should use commercial off-the-shelf (COTS) integrated circuits and components. (7 points each)
HW#7 due Monday, October 24, Lecture 15, work problems 32.11 and 32.12 here
HW#6
due Monday October 17, Lecture 13, work book problems 6-4 and 6-17.
Verify your hand calculations using LTspice.
hw5.pdf, due Wednesday, October 12, Lecture 11
hw4.pdf, due Monday, September 26, Lecture 8
hw3.pdf, due Monday, September 19, Lecture 6
hw2.pdf, due Monday, September 12, Lecture 4
hw1.pdf, due Wednesday, September 7, Lecture 3