Download Controlling the Motor

Induction Motor Vector
Control
Group F
Group Members and Responsibilities
• Justin Barwick (EE)
• Control System (Design)
• Control System Implementation
(Secondary)
• Chris Guido (CpE)
• Control System Implementation
• User Interface
• Merritt Robbins (EE)
• Power System (High Voltage)
• Will Santos (EE)
• Power System (Low Voltage)
Motivation
• Electric motors are an already enormous, ever - expanding industry
• ~45% of the world’s electricity (Waide, 2011) [1]
• AC induction motors offer performance benefits vs DC motors
• Efficiency
• Reliability
• Simplicity
• Electric transportation systems
• Tesla Motors
• Variable - speed industrial applications
• Machine tools
• HVAC
Goals and Objectives
• Implement Field Oriented Control
(FOC)
• Design high voltage power system
(325V DC bus)
• Low voltage DC bus regulation
• 15V, 8.5, 4V, 3.6V, 3.3V
• Implement two embedded
processors
• Divide computation to improve
performance
• High voltage Isolated
Measurements
• Phase voltage, current
• Temperature
Controlling the Motor
Utilizing Space Vector Pulse-width Modulation
Overview
• V/Hz Conversion
• Clarke and Park Transformation
• Inverter State Projections
• PWM Generation
Generating the Reference Signal
• Speed to Frequency Conversion
• Volts over Hertz Conversion
Speed to Frequency Conversion
• Determine number of poles
𝑅𝑃𝑀 =
120 ∗ 𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦
𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑃𝑜𝑙𝑒𝑠
• Receive voltage from
potentiometer
• Convert voltage to speed and
speed to frequency
Volts over Hertz Conversion
V/Hz Conversion
250
• Determine operating boundaries
• Maintain constant flux
Voltage (V)
200
150
100
50
0
0
5
10 15 20 25 30 35 40 45 50 55 60 65
Frequency (Hz)
Performing Transformations
• Clarke Transformation
• Park Transformation
Clarke Transformation
• Geometric relationship
1
𝛼
𝛽 =
0
2
0
3
1
2
1
1
−
−
2
2
𝑎
3
3
𝑏
−
2
2 𝑐
1
1
2
2
• Two pair-pole windings
• Power invariance
• Benefits:
• Independent variable reduction
• Intermediate step
Clarke Transformation
C
• Geometric relationship
• Two pair-pole windings
B
• Power invariance
A
• Benefits:
• Independent variable reduction
• Intermediate step
Clarke Transformation
C
45⁰
• Geometric relationship
C’
• Two pair-pole windings
B
45⁰
• Power invariance
A
A’
B’
• Benefits:
• Independent variable reduction
• Intermediate step
Clarke Transformation
C
• Geometric relationship
• Two pair-pole windings
0
B
• Power invariance
≈ 35.3⁰
A
α
β
• Benefits:
• Independent variable reduction
• Intermediate step
Clarke Transformation
β
• Geometric relationship
Nαβ
B
• Two pair-pole windings
Ns
120⁰
Nαβ
A, α
• Power invariance
• Benefits:
C
• Variable reduction
• Intermediate step
Park Transformation
• Geometric relationship
• Rotating reference frame
• Benefits:
• Variable simplification
• Independent control of torque and
flux
𝑑
cos 𝜃
𝑞 = − sin 𝜃
0
0
sin 𝜃
cos 𝜃
0
0 𝛼
0 𝛽
1 0
Park Transformation
β
Nαβ
B
• Geometric relationship
θ
• Rotating reference frame
θ
Ns
120⁰
• Benefits:
• Variable simplification
• Independent control of torque and
flux
C
Nαβ
A, α
Park Transformation
q
ω = synchronous speed
δ = slip of rotor
Nαβ
B
• Geometric relationship
ωt+δ
• Rotating reference frame
ωt+δ
Ns
120⁰
• Benefits:
• Variable simplification
• Independent control of torque and
flux
C
Nαβ
A, d
Space Vector Pulse-width Modulation
• Space Vector Mapping
• Inverter State Projections
• PWM Generation
Space Vector Mapping
• Phase and polarity
assignment
• Minimize inverter
switching
Space Vector Mapping
Inverter
State
C phase
B phase
A phase
V0
0
0
0
V1
0
0
1
V2
0
1
0
V3
0
1
1
V4
1
0
0
V5
1
0
1
V6
1
1
0
V7
1
1
1
• Phase and polarity
assignment
• Minimize inverter
switching
Space Vector Mapping
V3 (011)
B, V2 (010)
• Phase and polarity
assignment
60⁰
A, V1 (001)
V6 (110)
• Minimize inverter switching
C, V4 (100)
V5 (101)
Inverter State Projections
V3 (011)
B, V2 (010)
tmVs
t3V3
60⁰
A, V1 (001)
V6 (110)
t1V1
C, V4 (100)
V5 (101)
Pulse-width Modulated Signal Generation
• Utilize bit assignment
• Utilize zero-sequence
components
Control for Demo
• PI complications
• Determining the integral and
proportional gains
• Park Transform complications
• Frequency and phase detection
• Phase locking the sampled and
reference signal
Design Approach
• Mathematical Modeling
• Numerical Calculation
• Schematic Capture
• KiCad EDA suite
• Power System
• Separate high voltage from control system on different boards
• High efficiency focus
General Design Decisions
• Motor Selection
• Reliance Electric ½ HP, 230V/460V fan cooled
• Power Output Specification
• 1/2hp = 373W
Synchronous Rectifier Gate Driver
Part Number
IR1167
Manufacturer
International Rectifier
Input Voltage
12 ~20V
T_on / T_off
40ns / 60ns
Maximum Drain Sense Voltage
200V
Package
8 - SOIC (Standard)
Cost
$2.70 (1 qty)
• Emulated ideal diode with a
MOSFET
• Senses V_DS and drives gate
accordingly
• Easy package to work with
• Trimmable turn off threshold
Synchronous Rectifier Switches (MOSFET)
Part Number
TK62N60X
Manufacturer
Vishay / SIliconix
Rated V_DS
400V
Rated I_D
10A
R_DS (ON)
300 mOhm
Package
TO-247
Cost
$2.70 (1 qty)
•
•
•
•
Low cost for 400 V rating
0.3 Ohms * 0.4 A2 = 0.048 W
Common package
10 V gate charge
Power Inverter Gate Driver
Part Number
FAN7190M_F085
Manufacturer
Fairchild
High Side Voltage
650V
Minimum Pulse Width
80ns
Package
8 - SOIC (Standard)
Cost
$1.62 (1 qty)
• Standard package
• High and low side in one chip
• Capable of driving around 0.299.8% duty cycle at 20 kHz
switching frequency
Power Inverter Switch (IGBT)
Part Number
FGA5065ADF
Manufacturer
Fairchild
Ratec V_C
650V
Cont. I_C
50A (100A pulses)
Package
TO - 3PN
Cost
$4.79 (1 qty)
• Small package
• Extremely high current rating
• Low losses
Synchronous Rectifier Gate Driver
Part Number
CR8348-2000-F
Manufacturer
CR Magnetics Inc.
Frequency Range
20Hz ~ 200kHz
Current Rating
50A
Turns Ratio
1:2000
Package
24x11mm Thru-Hole
Cost
$7.05 (1 qty)
• High turns ratio for low power
sensing
• Selfisolates
• Eliminating the need for isolation
amplifiers
• Decently sized packages
• Perfect frequency range for
application
Adapter Board
• Flat flex connectors were partially mirrored
• Designed an adapter board
• Delivery scheduled 11/28/16
• Arrived this morning
Rotary Encoder
Part Number
AEAT-601B
Manufacturer
Broadcom / Avago
Cycles per Revolution
256
Channels
3 (A,B,I)
Package
Shaft Mounted (5mm)
• Three channels indicating position,
direction, and complete revolution
• Tolerant of high temperatures
(125°C)
Low Voltage Power System
By William Santos
Low Voltage Regulation
Regulator Design Considerations
• Efficiency/Power Dissipation
• Application (Switching or Linear Regulation)
Switching Regulator Selection
• Texas Instruments TPS54560
• Linear Technology LTC3649
Linear Voltage Regulation
• Linear Technology LT3008
• Texas Instruments TPS73130
Full Wave Schottky Bridge Rectifier
Purpose
• Provides the main DC bus for the Low Voltage Electronics
Design Considerations
• Diode Type (Schottky)
• Low Vf
• Good Conduction Characteristics
• Smoothing Capacitance
NXP
PMEG3050
Manufacturer
Average Forward 5A
Current
Forward Voltage
300 mV
Package
SOD-123
Switching Regulator IC Considerations
• Losses
• Switching loss, gate drive loss, and supply current losses are negligible
• Conduction loss provides the largest contribution to total power dissipation
• Power and Efficiency Characterization
Switching
Regulator
Max Power
Dissipation
Efficiency
TPS54560
1.02 W
85%-90%
LTC3649
1.82 W
85%-90%
TPS54560
• Purpose
• Provides the 15 V rails referenced to
the DC_Link- for the inverter
• Provides 4 V LV DC rail for other
regulator loads
• Selection Criteria
• Low Power Dissipation
• High Efficiency at normal loads
• PCB Layout Considerations
• Frequency Dependent Elements
• Catch Diode/Inductor
• Need to be close to SW pin
Manufacturer
Texas Instruments
Part Number
TPS54560
Power Required
20V
Switching Frequency
100 kHz-2MHz
Output Current (Max)
5A
Package
HSOP(8)
Efficiency
85%-90%
Price
$5.65
15V Output Switch Mode Power Supply
Switching Regulator Catch Diode Selection
• Purpose
• Reverse Polarity Protection
• Selection Criteria
• Peak Reverse Voltage
• Conduction Loss Minimal (1.5W at
worst)
• Low Vf
• Low Reverse Power Dissipation
Manufacturer
NXP
Part Number
PMEG4030ER
Peak Reverse Voltage
40V
Peak Output Current
3A
Package
SOD-123
Price
$0.41
LDO Linear Regulators
Purpose
• Provide supply voltages to the MCUs and Thermistor Sensors
Initial Selection
• LT3008 was chosen for post regulation to MCUs
• Output Current of 20 mA is much too small
Final Selection
• TPS73130 (150mA)
• LF33C (500mA)
TPS73130
Purpose
• Provides supply voltage to the Thermistor Networks
Advantages
• Simple Implementation
• Provides the appropriate output current
• Voltage Regulation Accuracy (1%)
LF33AB
Purpose
• Provides the supply voltage to the MCUs
Justification
• TMS Piccolo Sources max 100mA
• MSP430 Sources ~150 uA
Issues
• Determination of Induction Motor Parameters
• Performance of No Load and Blocked Rotor Test
• Need additional Resources
• Construction of encoder interface
• LCD screen
Budget and Financing
• Carey Family Donation - $500.00
• Self financed
Implementation
Utilizing the Piccolo Controller
TMS320F28027F Launchpad
• Selection Criteria
• High clock speed
• Enhanced control peripherals
• 4 ePWM channels
• 7 ADC channels with 13-bit resolution
Software Tools
• controlSUITE™
• Set of software infrastructure and tools
• Provides datasheets, libraries, and other resources for specific devices
Control Algorithm Implementation
Initialization
PWM Signal
Generation
If reference signal period not
reached
End of
reference
signal, or
motor not
spinning
Re-evaluate
Reference
Frequency
Initialization
• Configure Peripherals for
Operation
• CPU Timer
• ADC Channels
• Sample Window Size
• Conversion Triggers
• PWM Channels
• Clock Speed
• Time-Based Period
Initialization
PWM
Signal
Generation
Re-evaluate
Reference
Frequency
Initialization
• Initialize Frequency for Reference
Signal and Desired Frequency
• Sample ADC
• Initialize Flags
• Direction Flag
• Indicates that motor has changed
direction
• Change Flag
• Tells system that user wants motor to
change direction
• Is set when user presses button
Initialization
PWM
Signal
Generation
Re-evaluate
Reference
Frequency
PWM Generation
Initialization
PWM Signal
Generation
If reference signal period not
reached
End of
reference
signal, or
motor not
spinning
Re-evaluate
Reference
Frequency
PWM Generation
Check Toggle
Button
Check Counter
and Motor
Speed
Create
Reference
Signal
Send PWM
Signal
Clarke
Transformation
SVPWM
Calculation
PWM Generation
• Indicates user wants the motor to
spin in opposite direction
Check Toggle
Button
Check Counter
and Motor
Speed
Create
Reference
Signal
Send PWM
Signal
Clarke
Transformation
SVPWM
Calculation
PWM Generation
• Generate three signals based on
current motor status and desired
motor status
• Each signal is 120° out of phase of the
others
• Amplitude is determined by V/Hz
calculation
Check Toggle
Button
Check Counter
and Motor
Speed
Create
Reference
Signal
Send PWM
Signal
Clarke
Transformation
SVPWM
Calculation
PWM Generation
• Perform Clarke Transformation
• Determines equivalent α and β values
in rotated reference frame
Check Toggle
Button
Check Counter
and Motor
Speed
Create
Reference
Signal
Send PWM
Signal
Clarke
Transformation
SVPWM
Calculation
PWM Generation
• Projects α and β values onto
Inverter-State vector map
• Utilizes individual inverter states and
time durations
• Generates PWM duty-cycle as a ratio
of the Time-Based Period register
value
Check Toggle
Button
Check Counter
and Motor
Speed
Create
Reference
Signal
Send PWM
Signal
Clarke
Transformation
SVPWM
Calculation
PWM Generation
• Sets compare values for each PWM
channel to switch inverter states as
necessary
Check Toggle
Button
Check Counter
and Motor
Speed
Create
Reference
Signal
Send PWM
Signal
Clarke
Transformation
SVPWM
Calculation
PWM Generation
• Determines end of period of
reference signal
• Also determines if motor is no
longer spinning
Check Toggle
Button
Check Counter
and Motor
Speed
Create
Reference
Signal
Send PWM
Signal
Clarke
Transformation
• This indicates the motor is most likely
changing direction
• If either condition is met, revaluate
reference frequency.
• Otherwise repeat process
SVPWM
Calculation
Re-evaluate Reference Frequency
Initialization
PWM Signal
Generation
If reference signal period not
reached
End of
reference
signal, or
motor not
spinning
Re-evaluate
Reference
Frequency
Re-evaluate Reference Frequency
Reached End of Period
Check Change Flag
Flag
Is Set
Sample ADC for Desired Frequency
Motor is Not Spinning
Check Change Flag
Switch PWM Channels for
B and C Phase Voltages
Compare Desired Frequency with
Motor Speed
Decrement
Reference Signal
Frequency
Flag
Is
Not
Set
Set Direction Flag
Increment or Decrement Reference
Signal Frequency Accordingly
Reset Change and Direction Flag if
at Desired Speed
Reinitialize Counter
Increment Reference
Signal Frequency
Reinitialize Reference
Signal Frequency
Reinitialize Counter
Re-evaluate Reference Frequency (Reached
End of Period)
• Compares current
reference signal
frequency with
desired frequency set
by user
• Ramps reference
signal frequency up
or down accordingly
• Loops back to
generating PWM
Check Change Flag
Flag
Is Set
Sample ADC for Desired
Frequency
Compare Desired
Frequency with Motor
Speed
Decrement Reference
Signal Frequency
Increment or Decrement
Reference Signal
Frequency Accordingly
Reset Change and
Direction Flag if at
Desired Speed
Reinitialize Counter
Re-evaluate Reference Frequency (Reached
End of Period)
• If Change Flag is set,
motor is changing
directions
• Decreases reference
signal frequency until
motor is no longer
spinning
Check Change Flag
Flag
Is Set
Sample ADC for Desired
Frequency
Compare Desired
Frequency with Motor
Speed
Decrement Reference
Signal Frequency
Increment or Decrement
Reference Signal
Frequency Accordingly
Reset Change and
Direction Flag if at
Desired Speed
Reinitialize Counter
Re-evaluate Reference Frequency (Motor is
Not Spinning)
• Motor is not spinning and is not
changing direction
• This condition should only be met
when the system is starting up
Check Change Flag
Switch PWM Channels for
B and C Phase Voltages
Set Direction Flag
Reinitialize Reference
Signal Frequency
Reinitialize Counter
Flag
Is Not
Set
Increment
Reference Signal
Frequency
Re-evaluate Reference Frequency (Motor is
Not Spinning)
• Motor is not spinning and is
changing direction
• Switch PWM channels to reverse
direction of motor
• Loops back to generating PWM
Check Change Flag
Switch PWM Channels for
B and C Phase Voltages
Set Direction Flag
Reinitialize Reference
Signal Frequency
Reinitialize Counter
Flag
Is Not
Set
Increment
Reference Signal
Frequency
Issues
• Feedback System
• Park Transformation
• PI Controller
• User Feedback
• MSP430 Implementation
• SPI Communication
• LCD Display
Works Cited
[1] Waide, Paul, Brunner, Conrad U., et al.: Energy-Efficiency Policy Opportunities
for Electric Motor-Driven Systems. International Energy Agency Working Paper,
Energy Efficiency Series, Paris 2011