Lecture 10: Magnetic Levitation

1. Lecture 10: Magnetic Levitation IEE Culminating Lab & Timely Curricular Information Introduction to Engineering Electronics K. A. Connor

2. Magnetic Levitation Experiment • Magnets or magnetic materials can be suspended either using magnetic attraction or repulsion and permanent or electromagnets. Introduction to Engineering Electronics K. A. Connor

3. Magnetic Levitation • Trains can magnetically fly over a roadbed with position sustained by some kind of control system • Force can either be attractive or repulsive Introduction to Engineering Electronics K. A. Connor

4. Some Commercial Products http://www.gadgets4sure.com Introduction to Engineering Electronics K. A. Connor

5. The Physics of Levitron • The spinning top keeps itself stabilized vertically while the magnetic base keeps the top suspended. • http://www.levitron.com/ Introduction to Engineering Electronics K. A. Connor

6. The Physics of Levitron • The top actually precesses around the vertical axis (like the earth on its axis). • There is a range of stable revolutions per second (20-30). The weight must also be set to exactly balance gravity. Introduction to Engineering Electronics K. A. Connor

7. 2 Minute Quiz • Specify any design issue for repulsive levitation • Specify any design issue for attractive levitation Introduction to Engineering Electronics K. A. Connor

8. Maglev Experiment: How the Globes Are Suspended IR Emitter Electromagnet • From Barry’s Coilgun Design Site • Barry’s design is slightly more advanced • http://www.oz.net/~coilgun/levitation/home.htm Control Circuit IR Detector IR Light Beam Ball to be suspended Introduction to Engineering Electronics K. A. Connor

9. Maglev Experiment • Close up photos showing levitation of washer and ball bearing with magnet attached. Some preferred orientation is necessary for stability. Introduction to Engineering Electronics K. A. Connor

10. Unblocked Beam Blocked Beam Maglev Experiment • The position of the suspended object (here a ball) is sensed by how much of an IR beam is blocked by the object. • This requires an IR emitter and an IR detector. Introduction to Engineering Electronics K. A. Connor

11. Blocked Beam Maglev Experiment • The emitter puts out a constant light intensity. • The detector signal is amplified and compared with a reference voltage. • The output of the comparison drives the electromagnet. • If the ball is too high (detected IR signal too small), the coil current is reduced. • If the ball is too low (detected IR signal too large), the coil current is increased. Introduction to Engineering Electronics K. A. Connor

12. Maglev Experiment • The IR emitter and detector are powered just like the LEDs we used previously. The resistor in series gives us the best operation and also protects the diode. • Lab 2 on Diodes has the resistor. • Labs 5, 6, and 7 drive the LEDs directly. From Radio Shack Mini-Notebooks Introduction to Engineering Electronics K. A. Connor

13. Maglev Experiment • The photo emitter and detector circuits to be used in the experiment Introduction to Engineering Electronics K. A. Connor

14. Maglev Experiment • The circuit is constructed of the op-amp configurations we saw in Lab 4. • The actual circuit must also contain some mathematical operation for stable control. • This control in this case is analog. There are many other options. Inverting Op-amp Buffer Introduction to Engineering Electronics K. A. Connor

15. Maglev Experiment • For the inverting op-amp • For the buffer Inverting Op-amp Buffer Introduction to Engineering Electronics K. A. Connor

16. Maglev Experiment • First, two buffer circuits are used to isolate the control function (which we will return to). From Detector Buffer Buffer Introduction to Engineering Electronics K. A. Connor

17. Maglev Experiment Bias Buffered Input to Summing Inverting Op-amp Inverting Op-amp Introduction to Engineering Electronics K. A. Connor

18. Maglev Experiment • Voltage from op-amps drives transistor which provides the current for the electromagnet. Introduction to Engineering Electronics K. A. Connor

19. Maglev Experiment • How does the control work? • We need to look at different types of control. Control Introduction to Engineering Electronics K. A. Connor

20. Maglev: Types of Control Oven Temp Set Point Temp Power • On-Off Control (also called Bang-Bang) • Commonly used for thermostats. When the temperature is to low (bang) it is on. When the temperature is too high (bang) it is off. • Note the large excursions in temperature and that hysteresis is used to delay turn on and turn off. Introduction to Engineering Electronics K. A. Connor

21. Maglev: Types of Control Set Point Temp • Proportional Control • The power W is proportional to the difference in temperature between the set point and the actual temperature. Note as gain increases, the temperature becomes more unstable but can get closer to the set point. Oven Temp For 3 gains Introduction to Engineering Electronics K. A. Connor

22. Maglev: Types of Control Oven Temp Set Point Temp Power • Proportional-Integral-Differential Control (PID) • Works the best but is more mathematically demanding since it is 3rd order. Introduction to Engineering Electronics K. A. Connor

23. Maglev: Types of Control • Proportional-Integral Control (PI): In a simple system where noise may be a problem, the derivative term is not used. This is the approach used in the Embedded Control Class. • More on control can be found at Feedback and Temperature Control from the University of Exeter and the Hacker’s Diet (really!) by John Walker. Introduction to Engineering Electronics K. A. Connor

24. Maglev Experiment: Controller • For a resistor: • For a capacitor: In Out Introduction to Engineering Electronics K. A. Connor

25. Controllers • PID Controllers can be implemented many, many different ways. • Analog input can be converted to digital and then processed in the digital domain before being converted back to analog to drive the coil. • Digital circuitry can be used. • A microcontroller (like in Embedded Control) can be programmed • Other options may be discussed in the next lecture. Introduction to Engineering Electronics K. A. Connor

26. Some Registration Week Information on Majors Related to IEE • Electrical Engineering • Computer and Systems Engineering • Electric Power Engineering • EE/CSE Dual Degree • EE/EPE Dual Degree • CSE/CS Dual Degree • EE/Applied Physics Dual Degree Introduction to Engineering Electronics K. A. Connor

27. ECSE Undergraduate Advisor • David Nichols – Available for advice any time Monday, Wednesday and mornings on Thursday. (JEC 6002) • Email: Nichols@ecse.rpi.edu Introduction to Engineering Electronics K. A. Connor

28. Electrical Engineering Science, Math, H&SS Core ECSE Core Engineering Core EE Core Concentration Restricted Electives Free Electives Introduction to Engineering Electronics K. A. Connor

29. Chem Mat I Calculus I&II Differential Eqns Physics I&II CS I H&SS (5) + PD II Applied Math Elective IEA IEE EG&CAD IED Embedded Control PD I&III Multidisciplinary Elective Electrical Engineering Science, Math, H&SS Core Engineering Core Introduction to Engineering Electronics K. A. Connor

30. Electric Circuits Computer Components and Operations Signals & Systems Probability for Engr. Applications Analog Electronics or Digital Electronics Fields and Waves I Microelectronics Technology Lab Elective Electrical Engineering ECSE Core EE Core Introduction to Engineering Electronics K. A. Connor

31. Automatic Controls Comm & Info Proc Computer Hardware Electromagnetics Electronic Circuits Power Electronics Manufacturing or Entrepreneurship Microelectronics Individualized Lab Elective Design Elective (no longer included in concentration) Electrical Engineering Concentration Specified Electives Introduction to Engineering Electronics K. A. Connor

32. Any ECSE or EPOW Used to satisfy concentration Can also include one ENGR course Any course at all Usually used up for dual degrees Most students take additional technical courses See undergrad handbook Electrical Engineering Free Electives Restricted Electives Introduction to Engineering Electronics K. A. Connor

33. Computer and Systems Engineering Science, Math, H&SS Core ECSE Core Engineering Core CSE Core Concentration Restricted Electives Free Electives Introduction to Engineering Electronics K. A. Connor

34. Chem Mat I Calculus I&II Differential Eqns. Physics I&II CS I&II Data Structures & Alg. H&SS (5) + PD II Applied Math Elective IEA IEE EG&CAD IED Embedded Control PD I&III Multidisciplinary Elective Computer and Systems Engineering Science, Math, H&SS Core Engineering Core Introduction to Engineering Electronics K. A. Connor

35. Electric Circuits Computer Components and Operations Signals & Systems Probability for Engr. Applications Computer Architecture, Networks and Operating Systems Software Engineering Elective Computer and Systems Engineering ECSE Core CSE Core Introduction to Engineering Electronics K. A. Connor

36. Automatic Controls Comm & Info Proc Computer Hardware Computer Systems Manufacturing or Entrepreneurship Individualized Software Engineering Elective Design Elective (no longer included in concentration) Computer and Systems Engineering Concentration Specified Electives Introduction to Engineering Electronics K. A. Connor

37. Any ECSE or CSCI Used to satisfy concentration Can also include one ENGR course Any course at all Usually used up for dual degrees Most students take additional technical courses See undergrad handbook Computer and Systems Engineering Free Electives Restricted Electives Introduction to Engineering Electronics K. A. Connor

38. Electric Power Engineering Science, Math, H&SS Core ECSE Core Engineering Core EPE Core Concentration Restricted Electives Free Electives Introduction to Engineering Electronics K. A. Connor

39. Chem Mat I&II Calculus I&II Differential Eqns Physics I&II C Prog. For Engineers H&SS (5) + PD II IEA Engr. Proc. Or IEE EG&CAD IED MAU Modeling & Control of Dynamic Systems Embedded Control Electronic Instrumentation PD I&III Thermal & Fluids Engr. Multidisciplinary Elective Electric Power Engineering Science, Math, H&SS Core Engineering Core Introduction to Engineering Electronics K. A. Connor

40. Electric Circuits Fields & Waves I Signals & Systems Power Engineering Fundamentals Electromechanics Semiconductor Power Electronics EPE Lab EPE Design Electric Power Engineering ECSE Core EPE Core Introduction to Engineering Electronics K. A. Connor

41. Not required for EPE degree Optional Concentration in Power Electronics Systems -- Includes courses from EPOW, ECSE, & MANE Technical Elective – any course in Engineering or Science above the 2000 level Electric Power Engineering Concentration Specified Electives Introduction to Engineering Electronics K. A. Connor

42. Any course at all Usually used up for dual degrees Most students take additional technical courses See undergrad handbook Electric Power Engineering Free Electives Introduction to Engineering Electronics K. A. Connor

43. EE/CSE – Includes only the CSE concentrations (130 credits) CSE/CSYS – Includes all CSE concentrations (131 credits) EE/EPE – Includes only the Power Electronics concentration (131 credits) EE/Applied Physics – Includes only the Microelectronics concentration (132 credits) Dual Degrees Introduction to Engineering Electronics K. A. Connor

44. Check ECSE webpage during registration period New Undergraduate Handbook New design course options ECSE Design Control Systems Design Other courses will be changing Please check advising information on a regular basis Recent Changes Introduction to Engineering Electronics K. A. Connor