Precision Variable Frequency Drive May 07-13

1. Precision Variable Frequency DriveMay 07-13 Client: Jim WalkerAdvisor: Dr. AjjarapuTeam Members:Matt ShriverJason KilzerNick NationDave ReinhardtApril 24, 2007

2. Presentation Outline • Introductory Materials (Nick) • Project Approach & Design (Jason) • Testing and Implementation (Matt) • Closing Materials (Dave)

3. The Prototype

4. List of Definitions • VFD: Variable Frequency Drive • PWM: Pulse Width Modulation • IGBT: Insulated Gate Bipolar Transistor

5. Acknowledgements • Faculty advisor Dr. Ajjarapu • Client Jim Walker • Graduate Students • Ryan Konopinski • Sheng Yang

6. General Problem Statement • The speed control of an AC synchronous motor. • The synchronous motor and the subsequent drive mechanism do not always keep the correct speed. • A method is needed to control the frequency that is delivered to the synchronous motor.

7. Solution • A precision variable frequency drive will allow the user to manually change the operating frequency.

8. Operating Environment • Indoors • No extreme conditions • Near power outlet

9. Intended Use • As a drive for a low power AC synchronous electric motor. • This drive was not considered to be used on any other type of electric motor except for a synchronous design. • This drive shall not be used to power any control circuits.

10. Intended Users • Anyone who desires precise control over a small AC synchronous motor. • An owner of a turntable who needs better control over the speed of their turntable. • No technical knowledge will be required to operate the Precision VFD.

11. Assumptions • Constant linkage –An increase in motor speed by a certain factor will result in an increase in the speed of the turntable by the same factor. • Plug – the power cord from the record player can plug into a standard three pronged outlet.

12. Limitations • Minimum Power Output: 75 W • Output Frequency Range: 58-62 Hz • Frequency Precision: 0.001 Hz • Frequency Stability: < ± 0.01 % • 12” by 12” by 6” size limitation • Cost less than $350

13. Expected End Product • Precision variable frequency drive • Portable strobe system • One-page quick users guide • Circuit diagrams and parts list

14. Project Approach

15. Present Accomplishments • Research technologies (100%) • Simulate entire system (100%) • Purchase components (100%) • Build components (85%) • Test components (70%) • Build entire system (70%)

16. Approaches Considered

17. Project Definition Activities • Develop a VFD that will provide a precise frequency that can be changed. • A strobe light will also be included to measure the RPM of the electric motor.

18. Research Activities (1 of 2) • Pulse Width Modulation • Needs small signal variable frequency sine wave • Need small signal triangle wave • Comparator produce pulses from comparison of sine and triangle wave • PWM would create the control signals for the IGBT bridge

19. Research Activities (2 of 2) • IGBT Bridge • Provides power separation between PWM circuits and power supply circuitry • Generates pulses

20. Precision Variable Frequency Drive • Ready to use design • Delivers precise frequency control for low power AC synchronous motors • Strobe light included to measure RPM of motor

21. Design • Pulse Width Modulation Circuits • IGBT Bridge and Filter Circuits • Power Supply Circuits

22. Overall Block Diagram (1 of 2)

23. Overall Block Diagram (2 of 2)

24. Pulse Width Modulation Circuits

25. IGBT Bridge and Low Pass Filter

26. Power Supply Components • Astrodyne Power Supply (PT-45C) • Input: 120 VAC • Outputs: +/-15V, +5V • Filament Transformer • Primary Winding: 117V • Secondary Winding: 8V

27. Testing and Implementation

28. PWM Circuits

29. Comparator Input/Output Waveforms

30. Inverter Input/Output Waveforms

31. IGBT Bridge and Low Pass Filter

32. Filter Input/Output Waveforms Input and Output Waveforms of the Low Pass Filter

33. Implementation and Testing • Function generator chips • Amplifiers • Comparator and Inverter • IGBT’s • Filter • Strobe light system

34. Sine & Triangle Generator Chips • Built and tested on breadboard

35. Amplifiers, Comparator, and Inverter Circuits • Built and tested on breadboard

36. Comparator Testing Comparator Chips • UA741 Op Amp • LM319N High Speed Comparator Sources • Lab Function Generators • Function Generator Chips

37. IGBT Bridge • build and test on breadboard

38. IGBT Bridge Testing • Design overlooked need for delay circuitry • Tried multiple timing circuits • NE555 Timer Circuit • UA741 Op Amp Circuit

39. Strobe Light System Strobe Light Schematic

40. Closing Material

41. Resources

42. Schedule Detailed Gantt Chart

43. Deadline Schedule Deadlines Schedule

44. Project Evaluation (1 of 2)

45. Project Evaluation (2 of 2)

46. Commercialization • Not produced for commercialization • Precision variable frequency drive could be implemented for much less than current market price (~$250)

47. Additional Work • Resolve comparator issues • Resolve IGBT issues • Combine Precision VFD and strobe light system into one product • Include feedback loop for total autonomy

48. Lessons Learned (1 of 2) • What went well • Design/Simulation of project • Testing • What did not go well • Problem definition and planning (needed a new plan when we started implementing) • Having everyone on the same page (team members, advisor, vendor)

49. Lessons Learned (2 of 2) • Technical • Implement and test one component at a time • Keep it simple • Comparator troubleshooting • IGBT implementation • Non-technical • Should have planned a lot more time for implementation • Everyone must be on the same page • Have a good plan to start

50. Risk and Risk Management