Efficient Motor Control and Power Conversion System

1. Team MotorBoard Efficient Motor Control and Power Conversion System Preliminary Design Review 29 January 2009 Nicholas Barr, Daniel Fargano, Kyle Simmons, Marshall Worth

2. Project Summary • Design and prototype an efficient motor control and power conversion system to interface between a 200VDC source and an AC induction motor for both driving and generating power stages

3. Project Purpose • Comply with IEEE Future Energy Competition requirements • 1 kW motor • 3000 RPM cruising speed • 200 Volts DC source • 75% efficiency as a motor (3000 RPM) • 75% efficiency as a generator (3000 RPM) • Locked rotor torque of 30 N-m, for duration of 3 to 5 seconds • Initial load of 30 N-m and reach the speed of 3000 rpm within 3 to 5 seconds • Quickly and safely become an alternator

4. Project Purpose • Produce a viable option for industry • Quick and efficient interface for generating and driving • Possible application in hybrid vehicle motor drives • Cheap and easy way to get a 3-phase, high power pure sign wave

5. IEEE/APEC • Dan and Kyle will be going to Washington D.C. • Feb. 13th – 17th • Presenting IFEC progress report to IEEE • Attending Applied Power Electronics Conference • Power Converters • Motor Drive • Efficiency

6. Motor • 3 HP, 3600 RPM general purpose motor • Baldor • 84% efficient at 3600 rpm

7. System Diagram

8. Control System

9. Control System • LPC-P2148 Olimex devo board • NXP LPC2148FBD64-S • Program Memory Size: 512KB • RAM Size: 40KB • Package / Case: 64-LQFP • Speed: 60MHz • Core Processor: ARM7 • Data Converters: A/D 14; D/A 1 • Core Size: 16/32-Bit • Interface: I²C, SPI, SSP, UART, USB

10. Sensors • 3 Hall-effect current sensors for a,b,c line detection • Quadrature encoder (fancy shaft encoder) • Most likely optical • Prefer absolute position sensor • DC line voltage sensor • Optional (safety): • Temperature sensor

11. Control Algorithm • The objective of the controls algorithm is to sense a set of inputs from the motor and control board and produce a corresponding 3-phase output voltage. • First we sample the current in phase A,B and C as well as the position and speed of the rotor shaft • Second we determine the motor operating mode, motoring or generating, and the desired speed of operation. • From these quantities the desired DC-DC converter output voltage and phase A,B and C voltages are calculated. • Finally the controller will determine the appropriate duty cycle to emit on the IGBT gate driver input in order to produce the desired voltage at both the output of the DC-DC converter as well as the phase A,B and C voltages produced by the inverter.

12. Power System • 195VDC line to supply from Veriac • Large DC supply line capacitor • Input from control • Bidirectional Buck-Boost Converter • Input from control • Bidirectional DC  3-phase AC inverter

13. Power System

14. Simulated 3 Phase Waveforms

15. Test Methodology – Converter • Specifications: • 95%+ efficiency • DC input to Bucked/Boosted DC output • Test: • At specific duty cycle and input voltage -> Measure and Compare Output voltage to theoretical output voltage determined by the conversion ratio M(D)= -D/(1-D) • Swing the input voltage at specific duty cycle to confirm it works for various voltages • Change the duty cycle and repeat the voltage swing to ensure the converter works at all duty cycles and voltages • If either of the test specifications is not met the inverter must be checked against the schematic design of converter to ensure all components are properly placed and have solid connections.

16. Test Methodology – Inverter • Specifications: • 95%+ efficiency • DC input -> 3 phase AC output • Test: • Swing input voltage and monitor output. Peak AC voltage should be no less than 75% of the DC value • At each voltage level, check for clean sinusoidal AC signal and that all 3 phases are 120 degrees apart • If either of the test specifications is not met the inverter must be checked against the schematic design of the inverter to ensure all components are properly placed and have solid connections.

17. Test Methodology – Controls • Specifications: • Control the gates of both the converter and inverter • Test: • Use a logic analyzer to make sure we are getting the correct signals on the output terminals • We will connect the controls to the inverter and converter to see if it will actually control the gates of the transistors • If the controls are not working, use the logic analyzer to check the entire board to make sure all signals are producing correct signals and check it against the schematic to ensure the accuracy of the controls.

18. Marketability • Society is going green  energy conservation • Makes for more efficient use of the power • Perfect addition to hybrid vehicles • Many companies are focusing on hybrid-electric drive systems but are lacking bi-directionally, specifically the generation of power • This could serve as a quick fix or serve as a prototype for future drive systems

19. Environmental Impact &Impact on Society • Shift in attitudes is moving interest towards electric vehicles • Increasing ease and efficiency of battery to motor interface might allow quicker to-market designs • Manufacturing of board can be done in a manner which reduces impact on environment (RoHS)

20. Sustainability • Many of the parts we will be using in our project are accessible through multiple vendors at low cost. There are no specialty components that would limit us or this project to purchase from any specific vendor. • Motor designed for is very common • Electric motors will always be used, independent of their use in vehicles • The most likely component to fail would be the IGBTs on the inverter which could blow if we don’t account for current spikes in the switching.

21. Manufacturability • Will need to meet FCC/RoHS standards • Easy to debug due to breakout pins • The tolerances on the components shouldn’t be that big of an issue for this project. We are aiming to have an efficiency of at least 75% which will rely heavily on our designs of the power electronics and the motor itself but for individual components the tolerances of typical resistors, capacitors, inductors, etc should be adequate for our needs.

22. Costs of Manufacturing • Should be relatively cheap and marketable/profitable • $50 for controls • $40 for power components • $20-$30 for sensors/power/etc

23. Safety • Potentially dangerous due to high current/voltage • No user access to switching • Design for shock resistance • Proper grounding • High voltage isolation from low voltage controls

24. Division of Labor • Converter Hardware • Buck Boost • Marshall • Nick • 3 Phase Inverter • Kyle • Dan • Controls • Software • Marshall • Nick • Propagation • Kyle • Dan • PCB Design • Nick • Kyle • Testing/Verification • All • Text • All • Presentation • All

25. Project Milestones • CDR- part selection/bought, system schematics, basic power system and basic microcontroller functionality • Milestone I - all hardware working on protoboard, sensors configured and working, and final revision of PCB completed and sent out • Milestone II – working prototype, PCB built and populated • EXPO – final debug, packaging, documentation done

26. Schedule Overview • Buck-Boost Converter: Jan 19-Feb 19 • DC:AC Inverter: Jan 19-Feb 19 • PCB layout: Feb 20 – March 11 • Software: Feb 20 – April 6 • Project Completion: April 16

27. Money • Primary Funding: • Fall 2008 EEF mini-proposal applied for and received ($2k)  • Spring 2009 UROP Funding ($1k) • Secondary Funding: • Prize money from the IFEC 2007 competition(~$3k) • This money needs to cover the motor design team as well • Department funding from Lightner ($5k) • Backup Funding: • Professor Barnes has a large grant for student research projects ($10k+)

28. Budget

29. Risks and Contingency Plan • Lack of proper efficiency • Focus on driving side, less emphasis on generating • Hand wired motor • Current spikes • Designed to have peak current double what we expect • Most parts interchangeable with higher rated components • PCB fabrication problems • We can wire wrap or use devo board

30. Questions?