Efficient Motor Control and Power Conversion System Team MotorBoard Preliminary Design Review 29...
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Transcript of Efficient Motor Control and Power Conversion System Team MotorBoard Preliminary Design Review 29...
Efficient Motor Control and Power Conversion System
Team MotorBoard
Preliminary Design Review29 January 2009
Nicholas Barr, Daniel Fargano, Kyle Simmons, Marshall Worth
Project SummaryDesign 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
Project PurposeComply 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
Project PurposeProduce 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
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
Motor3 HP, 3600 RPM
general purpose motor
Baldor 84% efficient at
3600 rpm
System Diagram
Control System
Control SystemLPC-P2148 Olimex devo boardNXP 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
Sensors3 Hall-effect current
sensors for a,b,c line detection
Quadrature encoder (fancy shaft encoder)Most likely opticalPrefer absolute position
sensorDC line voltage sensorOptional (safety):
Temperature sensor
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.
Power System195VDC line to
supply from Veriac Large DC supply line
capacitorInput from control
Bidirectional Buck-Boost ConverterInput from control
Bidirectional DC 3-phase AC inverter
Power System
Simulated 3 Phase Waveforms
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.
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.
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.
MarketabilitySociety is going green energy conservationMakes for more efficient use of the powerPerfect 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
Environmental Impact &Impact on SocietyShift 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)
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.
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.
Costs of ManufacturingShould be relatively cheap and
marketable/profitable$50 for controls$40 for power components$20-$30 for sensors/power/etc
SafetyPotentially dangerous due to high
current/voltageNo user access to switchingDesign for shock resistanceProper groundingHigh voltage isolation from low voltage
controls
Division of Labor
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
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
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+)
BudgetItem Quantity Total Cost
PCB Fabrication 2 $150
Microprocessor 1 $15
Controls parts 2 $60
IGBTs 15 $375
Drivers 4 $30
Power Electronics parts
? $20
Sensors 4 $50
Packaging 1 $100
Printing/Poster/etc 1 $75
Shipping $90
Total $965
Risks and Contingency PlanLack of proper efficiency
Focus on driving side, less emphasis on generating
Hand wired motorCurrent spikes
Designed to have peak current double what we expect
Most parts interchangeable with higher rated components
PCB fabrication problemsWe can wire wrap or use devo board
Questions?