Single-phase Variable Frequency Switch Gear

Transcription

1 1 Single-phase Variable Frequency Switch Gear Department of Electrical and Computer Engineering Eric Motyl and Leslie Zeman Advisor: Steven D. Gutschlag October 1, 2015

2 2 Outline Background Design Approach and Method of Solution Economic Analysis Schedule Division of Labor Societal and Environmental Impacts Summary and Conclusions

3 3 Outline Background Problem Background Problem Statement Constraints Design Approach and Method of Solution System Block Diagram Subsystem Block Diagram Availability of Equipment Testing

4 4 Problem Background Variable frequency drive Controls the speed of a three-phase AC motor by varying the frequency and voltage supplied to the motor [1]

5 5 Problem Background Importance of variable frequency drives: Provide energy efficiency benefits to industries that consume large amounts of power operating AC machines [2] Match the speed of the motor driven equipment to load requirements Extend equipment life Smooth startup of AC motors reduces belt, gear, and bearing wear Reduces shaft fatigue

6 6 Problem Statement Design, build, and test single-phase variable frequency switch gear Switch gear driven by a single-phase 60 Hz AC supply voltage System generates an output voltage with a constant Volts/Hertz ratio and a variable frequency in the range of 1 to 60 Hz

7 7 Constraints Single-phase variable frequency switch gear must: Provide output frequencies in the range of 1 to 60 Hz Use devices rated for a current of 1.5 A RMS Have a grounded neutral Be safe

8 8 System Block Diagram Single-phase 60 Hz AC Supply Voltage Frequency Select Input Variable Frequency Switch Gear Single-phase, Variable Frequency Output with Constant V/Hz Ratio

9 9 Subsystem Block Diagram Single-phase 60 Hz AC Supply Voltage Rectifier Gate Drive Circuitry + Vdc Frequency Select Input PWM Generation Controller Upper half PWM Lower half PWM DC-to-AC Voltage Inverter Vdc Single Phase Variable Frequency Output with Constant V/Hz Ratio

10 10 Subsystem Block Diagram Single-phase 60 Hz AC Supply Voltage Rectifier Gate Drive Circuitry + Vdc Frequency Select Input PWM Generation Controller Upper half PWM Lower half PWM DC-to-AC Voltage Inverter Vdc Single Phase Variable Frequency Output with Constant V/Hz Ratio

11 11 PWM Generation Controller Atmega 128 Atmel AVR Development Board Generate triangle wave and half-wave rectified sine wave Compare the two waves If the triangle wave is greater than the sine wave, toggle bit on output port high If the triangle wave is less than the sine wave, toggle bit on output port low Every other half cycle will control a separate bit on a given output port (e.g. PA0 and PA1)

12 12 Subsystem Block Diagram Single-phase 60 Hz AC Supply Voltage Rectifier Gate Drive Circuitry + Vdc Frequency Select Input PWM Generation Controller Upper half PWM Lower half PWM DC-to-AC Voltage Inverter Vdc Single Phase Variable Frequency Output with Constant V/Hz Ratio

13 13 Gate Drive Circuitry Two 8-pin Avago HCPL-3120 chips 18 V supply High and low side drivers Avago Technologies HCPL-3120 data sheet

14 14 Subsystem Block Diagram Single-phase 60 Hz AC Supply Voltage Rectifier Gate Drive Circuitry + Vdc Frequency Select Input PWM Generation Controller Upper half PWM Lower half PWM DC-to-AC Voltage Inverter Vdc Single Phase Variable Frequency Output with Constant V/Hz Ratio

15 15 DC-to-AC Voltage Inverter Fairchild FMG2G75U560 IGBT Pair +V DC and -V DC voltage rails +VDC Upper Half PWM Load Lower Half PWM - VDC

16 16 Availability of Equipment Atmega128 AVR Development Board Avago HCPL-3120 Fairchild FMG2G75U560

17 17 Key Component of Solution PWM generation controller Contingency plan: Function generator and LM311 comparators to substitute in for software used to generate the switched PWM that will drive IGBTs

18 18 Testing PWM generation controller Gate drive circuitry and DC-to-AC voltage inverter

19 19 Testing PWM Generation Controller External DtoA to see generated sine and triangle waves with oscilloscope Oscilloscope to view switched PWM output on two bits

20 20 Testing Gate Drive and DC-to-AC Voltage Inverter Gate Drive Circuitry Use function generator to provide a PWM signal and verify that the output is correctly amplified DC-to-AC Voltage Inverter Verify that output of gate drive circuitry switches IGBTs as desired

21 21 Outline Economic Analysis Schedule Gantt Chart Division of Labor Societal and Environmental Impacts Summary and Conclusions

22 22 Economic Analysis Part Cost Atmega128A Atmel AVR development board kit $41.99 Avago HCPL-3120 $3.27 (2x) Fairchild FMG2G75US60 (IGBT) $30 LM311 $3.44 (10pcs) Total cost $82

23 23 Milestones 10/22/15 10/27/15 Code PWM Generation Controller Design Gate Drive 11/17/15 Design Inverter 11/26/15 12/3/15 Build Gate Drive Build Inverter 3/17/16 4/29/16 Testing Poster Presentation

24 24 Division of Labor Tasks Research Design Gate Drive Design Inverter Code PWM Generation Controller General Construction Testing Name(s) Assigned to Task Eric, Leslie Leslie Leslie Eric Eric, Leslie Eric, Leslie

25 Schedule 25

26 26 Safety Lab safety procedure Power lab rules Power turned off when not in use Power turned off before any changes Double check circuit Always have another member in the lab Lab Safety Clothing & Protection No bulky or loose fitting clothing Safety glasses

27 27 Safety Standards UL Safety requirements for power drive systems Refers to adjustable speed electric drive systems NEC, NFPA 70E Reducing exposure to major electrical hazards

28 28 Societal and Environmental Impacts Efficiency Benefits Lower cost for industries Equipment Life Equipment turnover Less turnover reduces cost Transportation Cranes and hoists Small vehicle drives Material handling conveyors

29 29 Conclusion Design of single-phase variable frequency switch gear will be accomplished through the design of its subsystems PWM generation controller Gate drive circuitry DC-to-AC Voltage Inverter

30 30 Single-phase Variable Frequency Switch Gear Department of Electrical and Computer Engineering Eric Motyl and Leslie Zeman Advisor: Steven D. Gutschlag October 1, 2015

31 31 References 1. Introduction to AC Drives, [Online]. Available: /ITACDS-D.PDF 2. C. Hartman. (2014). What is a Variable Frequency Drive, [Online]. Available: 3. K. Lemke and M. Pasternak. (2014). Variable Frequency AC Source, [Online]. Available: Proposal.pdf 4. K. Lemke and M. Pasternak, Variable Frequency AC Source (VFACS) Project Report, Bradley Univ., Peoria, IL, Variable Frequency Drive (VFD) [Online]. Available: n%20guide.pdf

32 Full Gantt Chart 32

33 33 PWM Generation Controller Flowchart Start Initialize Timer Create 2 V p-p 15 khz Triangle Wave Create desired sine wave Check: Triangle < sine Toggle output bit high Check: Triangle > sine Toggle output bit low Toggle output bit low