This document discusses efficient motor control solutions and Analog Devices' high performance servo control field programmable gate array (FPGA) module (FMC) board. It provides an overview of motor control strategies, feedback sensors, isolation requirements, and Analog Devices technologies that improve motor control system performance. The Analog Devices FMC solution addresses power, isolation, measurement, and control challenges in motor control applications. It allows accurate measurement of motor feedback signals and interfacing with Xilinx FPGAs.

1. Efficient Motor Control Solutions:
High Performance Servo Control
Reference Designs and Systems Applications
Andrei Cozma, Analog Devices

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2

3. Today’s Agenda
Motor control applications and target markets
Motor control strategies
Feedback sensors and circuits
Isolation
ADI high performance servo control FMC board
Using the ADI high performance servo FMC board with Xilinx®
FPGAs and Simulink® from Mathworks
3

4. Objectives
Provide insight into the operation of electric motor
drive systems and show where ADI technology adds
value to the system
Understand motor control strategies and the challenges
of designing efficient motor control applications
Show how some ADI motor control solutions can be used
with Xilinx FPGAs
Show how some ADI motor control solutions can be used
with Simulink from MathWorks®
4

5. Motor Control Applications
and Target Markets
Section 1
5

6. Electric Motor Applications
Electric motors are used in a wide range of applications
 Industrial
 Medical
 Transportation
 Automotive
 Integrated applications
 Communications
 Household appliances
6

7. Electric Motor Drives
Motor Drive
 A system that varies the motor electrical input power to
control the shaft torque, speed, or position.
Types of Drives
 Application specific drive—designed to run a specific
motor in a specific application (e.g., variable speed pump
drive).
 Standard drive—designed as a general-purpose motor
speed controller capable of running a variety of motors
within a given power range.
 Servo drive—designed to deliver accurate and high
dynamic control of position, speed, or torque down to
zero speed. Typically used in automation applications.
 High performance servos—designed to deliver best in
class accuracy and connectivity. Typically used in CNC
and pick and place machines.
7

8. Market Sub Segments in Motor Control
Partners and Systems Value from ADI
8
High End Servos/CNC
ADI + FPGA Vendors
Xilinx
Focus ADI Parts:
Isolation (Gate Drivers/Discrete)
AD740x + AMP
RDC + SAR ADC
Transceivers
Power
Accelerometers/Sensors
Servos and Premium
Drives
ADI Has Complete Signal
Chain + Select Partners
Focus ADI Parts:
ASSPs/SHARC/BF
Isolation (Gate Drivers/Discrete)
AD740x + AMP
RDC + SAR ADC
Transceivers
Power
Accelerometers/Sensors
Standard and Midrange
Motor Drives
ADI Has Complete Signal
Chain + Select Partners
Focus ADI Parts:
ASSPs/BF
Isolation (Gate Drivers/Discrete)
AD740x + AMPs
RDC + SAR ADC
Transceivers
Power
Applications Specific
Motor Control
ADI Has Part of Signal
Chain + Select Partners
Focus ADI Parts:
ASSPs / ADuC Family
Isolation (Gate Drivers/Discrete)
AMPs
SAR ADC
Transceivers
Power
Highest Value for
High Performance
FPGA and AFE

9. Market Trends
Save Energy
 Drive for performance and quality in motor control
 More than 40% of global energy consumed by motors
 The requirement for higher system efficiency means
there is a need to move from standard induction
machines to permanent magnet motors
 Shift from analog to digital control—focus on highest
possible efficiency
Impact of Trends
 Increases need for new performing technologies on:
converters, amplifiers, processors, isolation, power,
interfaces
 The need for higher controller performance makes
room for new technologies like FPGAs and other
advanced controllers to be used in motor control
systems
9

10. Motor Control Strategies
Section 2
10

11. Brushed DC Motor Control
11
 Vary the dc supply, and the motor speed
will follow the applied voltage
 Pulse width modulation
 Constant amplitude voltage pulses of varying
widths are provided to the motor: the wider the
pulse, the more energy transferred to the motor
 The frequency of the pulses is high enough that
the motor’s inductance averages them, and it
runs smooth
 A single transistor and diode can control
the speed of a dc motor
 The motor speed (voltage) is proportional to the
transistor ON duty cycle
 Positive torque only—passive braking
 An H-bridge power circuit enables four
quadrant control
 Forward and reverse motion and braking
 Complementary PWM signals applied to the high
and low side switches in the bridge

12. A
B C
BLDC
CONTROLLER
+
-
HALLA
HALLB
HALLC
Brushless DC Motor Control
12
 Brushless dc motors windings generate a
trapezoidal back EMF synchronized to the
position of the rotor magnet.
 Hall effect sensors detect the rotor magnet
position and provide signals indicating the
“flat top” portion for each winding’s back
EMF.
 Six switching segments can be identified.
 Star Connection Control
 For any one segment, two windings will be in the
“flat top” portion of the back EMF and a third
winding will be switching between a positive and
negative output.
 Electronic control leaves one winding open circuit,
connects one winding to the lower dc rail, and
controls the voltage applied to the third winding
using PWM.
 The fill factor of the applied PWM controls the
speed of the motor.

13. A
B C
BLDC
CONTROLLER
+
-
HALLA
HALLB
HALLC
Brushless DC Motor Control
13
 Delta Connection Control
 For any one segment, two windings are connected
to the positive voltage supply and a third winding is
connected to the negative voltage supply.
 The fill factor of the applied PWM controls the
speed of the motor.
 Sensorless control can be achieved by
detecting the zero crossings of the BEMF
for each phase
 Sensorless control benefits
 Lower system cost
 Increased reliability
 Sensorless control drawbacks
 BEMF zero crossings can’t be reliably
detected at low motor speeds

14. AC Motor Control
14
 Volts per Hertz Control
 Variable frequency drive for applications like
fans and pumps
 Fair speed and torque control at a
reasonable cost
 Sensorless Vector Control
 Does not require a speed or position
transducer
 Better speed regulation and the ability to
produce high starting torque
 Flux Vector Control
 More precise speed and torque control, with
dynamic response
 Retains the Volts/Hertz core and adds
additional blocks around the core
 Field Oriented Control
 Best speed and torque control available for ac
motors
 The machine flux and torque are controlled
independently
U
V
W
AC MOTOR
CONTROLLER
+
-
Ia
Ib
Speed

15. Field Oriented Control (FOC)
15
 Separates and independently controls the motor flux and torque
 Applies equally well to dc motors and ac motors and is the reason “dc
like” performance can be demonstrated using field oriented control on
ac drives
Torque
Controller
PI
Flux
Controller
PI
Inverse
Park
Transform
d,q → α,β
Space
Vector
PWM
3 Phase
Inverter
Forward
Clarke
Transform
a,b → α,β
Forward
Park
Transform
α,β → d,q
Vsq
Vsd
Vsα
Vsβ
Vsa PWM
Vsb PWM
Vsc PWM
AC
Motor
isa
isb
isα
isβ
isd
isq
Vsq
Vsd
VsqRef
VsdRef
_
+
+
_
VDC
Rotor Flux
Angle θ

16. Feedback Sensors and Circuits
Section 3
16

17. Current and Voltage Sensing
17
 Shunt Resistor
 Linear, wide BW, zero offset
 Power loss at high currents and
no isolation
 Current Transformer
 Isolating
 AC only with poor linearity at low current
 Hall Effect Current Sensor
 Isolating, dc operation and less expensive
than CT
 Nonlinearity and zero offset
 Nulling Hall Effect Sensor
 Isolating, dc operation and better linearity
than HE sensor
 More expensive and zero offset
 Voltage isolation
 Used to remove CM signal from dc bus,
motor voltage, and current shunt voltages
Isolating

18. Shaft Position and Speed Sensing Devices
Speed
 AC and DC tachometers are permanent
magnet generators that produce a
voltage proportional to speed.
 The ac tachometer output frequency is
also proportional to speed.
Commutation (Rotor Angle)
 Brushless dc motors require low
resolution feedback derived from the
motor magnets using Hall effect sensors.
 A Hall effect based magnetic encoder
generates a pulse train for speed and
incremental position.
Precision Shaft Angle
 Optical encoders with precision pattern
printed on a glass disk provide very high
resolution shaft position and speed data.
 Resolvers generate sine/cosine relative
to position. They are the analog
counterpart of the rotary encoder.
18

19. Sensorless Control
Eliminate mechanical speed/position sensors by calculating
feedback signal from other information
 Often used for rotor position estimation in PMSM and BLDC motors
 Very useful in estimating rotor flux position in ACIM FOC control
 In some cases, can provide better results than real sensors
Techniques
 BEMF detection to estimate rotor position in BLDC motor control
 Rotor angle detection based on motor model using measured phases currents
and voltages
Problems
 Variation of motor/model parameters over time, temperature
 Usually need special handling of low speed/zero speed and/or start-up
19

20. Isolation
Section 4
20

21. Safety and Functional Isolation
21
 Functional isolation protects electronic control
circuits from damaging voltages
 Isolate high voltage output from control circuits
connected to Power_GND
 Safety isolation protects the user from dangerous
voltages
 Protects user and electronic circuits
 International standard apply
 Typically requires double insulation barrier: single
device with two insulating layers OR two single
insulating layer devices in path to EARTH
 Isolation options
 Isolate power circuits from the control and user I/O
circuits
 Common in “noisy” high power systems
 Required when there is high BW communications
between control and communications process
 Isolate power and control circuits from user I/O
circuits
 Common in low power systems
 Simplifies signal isolation when there is limited
communications between control and user

22. Motor Control Signal Isolation—Isolated Power
Circuit
Feedback isolation
 Measure winding current using
isolating ADC
 Isolated RS-485 position data from
encoder ASIC
Inverter drive isolation
 Isolated high- and low-side gate
drivers
DC bus signal isolation
 Serial I2C ADC for analog signal
isolation
 Digital isolation of hardware trip
signals
Field Bus isolation
 Isolate CAN outputs from field bus
network
22

23. ADI High Performance Servo
Control FMC Solution
Section 5
23

24. FPGAs in Motor Control
FPGAs are becoming more popular for
motor control
 Wide integration capabilities
 Higher performance, reduced latency
 Cost reduction
FPGAs are used in a large number of
industry fields for efficient motor control
 Industrial servos and drives
 Manufacturing, assembly, and automation
 Medical diagnostic
 Surgical assist robotics
 Video surveillance and machine vision
 Power efficient drives for transportation
24

25. ADI FMC High Performance Servo Solution
Purpose
 Provide an efficient motor control solution for different types of
electric motors
 Address power and isolation challenges encountered in motor
control application
 Provide accurate measurement of motor feedback signals
 FPGA interfacing capability
Added Value
 Complete control solution showing how to integrate hardware for:
 Power
 Isolation
 Measurement
 Control
 Increased control flexibility due to FPGA interfacing capabilities
 Increased versatility to be able to control different types of
motors
 Example reference designs showing how to use the control
solution with Xilinx FPGAs and Simulink
25

26. ADI FMC High Performance Servo Solution
Drive Board
 Drives BLDC / PMSM / Brushed DC / Stepper motors
 Drives motors up to 48V at 18A
 Integrated over current protection
 Current measurement using isolated ADCs
 Bus voltage, phase currents and total current analog
feedback signals
 PGAs to maximize the current measurement input rage
 BEMF zero cross detection for sensorless control of
PMSM or BLDC motors
Controller Board
 Compatible with all Xilinx FPGA platforms with FMC
LPC or HPC connectors
 2 x Gbit Ethernet PHYs for high speed industrial
communication
 Hall + Differential Hall + Encoder + Resolver interfaces
 Current and voltage measurement using isolated ADCs
 Xilinx XADC interface
 Fully isolated control and feedback signals
26

27. ADI FMC Controller Board Block Diagram
27

28. ADI Low Voltage Drive Board Block Diagram
28

29. Key Parts Features That Improve System
Performance
 Efficient Motor Control Prerequisites
 High quality power sources
 Reliable power, control, and feedback signals isolation
 Accurate currents and voltages measurements
 High speed interfaces for control signals to allow fast controller response
29
Measurement
AD7401A 5 kV rms, isolated 2nd order Sigma-Delta modulator
AD8207 Zero drift, high voltage, bidirectional difference amplifier
AD8137 Low cost, low power differential ADC driver
Power
ADuM5000 isoPower® integrated isolated dc-to-dc converter
ADP1614 1000 mA, 2.5 MHz buck-boost dc-to-dc converter
ADP1621 Low quiescent current, CMOS linear regulator
Isolation
ADuM7640 Triple channel digital isolator
Voltage Translation
ADG3308 8-channel bidirectional level translator

30. AD7400A/7401A: 5 kV rms, Isolated 2nd Order
Sigma-Delta Modulator
 Features
 High performance isolated ADC
 16-bit NMC
 ±2 LSB (typ) INL with 16-bit resolution
 1.5 mV/°C (typ) offset drift
 ±250 mV differential analog input
 −40°C to +125°C operating temperature
range
 5 kV rms, isolation rating (per UL 1577)
 Maximum continuous working voltages
 565 V pk-pk: ac voltage bipolar waveform
 891 V pk-pk: ac voltage unipolar
waveform (CSA/VDE)
 891 V: dc (CSA/VDE)
 Ideal for motor control and dc-to-ac inverters
 Shunt resistor current feedback sensing
 Isolated voltage measurement
 External clocked version simplifies
synchronization
30
Product Data Rate Clock SNR ENOB INL Package
AD7400A 10 MHz Internal 80 dB 12.5 ±2 LSB SOIC-16
Gull Wing-8
AD7401A 20 MHz External 83 dB 13.3 ±1.5 LSB SOIC-16

31. AD8207: Zero-Drift, High Voltage, Bidirectional
Difference Amplifier
 Features
 Ideal for current shunt applications
 EMI filters included
 1 μV/°C maximum input offset drift
 High common-mode voltage range
 −4 V to +65 V operating (5 V supply)
 −4 V to +35 V operating (3.3 V supply)
 −25 V to +75 V survival
 Gain = 20 V/V
 3.3 V to 5.5 V supply range
 Wide operating temperature range: −40°C to
+125°C
 Bidirectional current monitoring
 <500 nV/°C typical offset drift
 <10 ppm/°C typical gain drift
 >90 dB CMRR dc to 10 kHz
 Qualified for automotive applications
 Applications
 High-side current sensing in
 Motor control
 Solenoid control
 Engine management
 Electric power steering
 Suspension control
 Vehicle dynamic control
 DC-to-DC converters
31

32. ADuM5000: Isolated DC-to-DC Converter
 Features
 isoPower® integrated isolated dc-to-dc
converter
 Regulated 3.3 V or 5 V output
 Up to 500 mW output power
 16-lead SOIC package with >8 mm
creepage
 High temperature operation
 105°C maximum
 High common-mode transient immunity
 >25 kV/μs
 Thermal overload protection
 Safety and regulatory approvals
 UL recognition
 2500 V rms for 1 minute per UL 1577
 CSA component accept notice #5A
(pending)
 Applications
 RS-232/RS-422/RS-485 transceivers
 Industrial field bus isolation
 Power supply startups and gate drives
 Isolated sensor interfaces
 Industrial PLCs
32

33. ADP1614: 650 kHz/1.3 MHz, 4 A, Step-Up, PWM,
DC-to-DC Switching Converter
 Features
 Adjustable and fixed current-limit options:
 Adjustable up to 4 A
 Fixed 3 A
 2.5 V to 5.5 V input voltage range
 650 kHz or 1.3 MHz fixed frequency option
 Adjustable output voltage, up to 20 V
 Adjustable soft start
 Undervoltage lockout
 Thermal shutdown
 3 mm × 3 mm, 10-lead LFCSP
 Supported by ADIsimPower design tool
 Applications
 TFT LCD bias supplies
 Portable applications
 Industrial/instrumentation equipment
 Design tools
 ADIsimPower - DC-DC Power
Management design tool
33

34. ADuM7640: 1 kV RMS Six-Channel Digital
Isolator
 Features
 Small 20-lead QSOP
 1000 V rms isolation rating
 Safety and regulatory approvals (pending):
 UL recognition (pending) 1000 V rms for
1 minute per UL 1577
 Low power operation
 3.3 V operation
 1.6 mA per channel maximum at 0 Mbps
to 1 Mbps
 7.8 mA per channel maximum at 25Mbps
 5 V operation
 2.2mA per channel maximum at 0 Mbps
to 1 Mbps
 11.2mA per channel maximum at 25Mbps
 Bidirectional communication Up to 25 Mbps
data rate (NRZ)
 3 V / 5 V level translation
 High temperature operation: 105°C
 High common-mode transient immunity:
>15 kV/μs
 Applications
 General-purpose, multichannel isolation
 SPI interface/data converter isolation
 RS-232/RS-422/RS-485 transceivers
 Industrial field bus isolation
34

35. ADG3308: Low Voltage, 1.15 V to 5.5 V, 8-
Channel Bidirectional Logic Level Translator
 Features
 Bidirectional logic level translation
 Operates from 1.15 V to 5.5 V
 Low quiescent current < 1 μA
 No direction pin
 Applications
 Low voltage ASIC level translation
 Smart card readers
 Cell phones and cell phone cradles
 Portable communication devices
 Telecommunications equipment
 Network switches and routers
 Storage systems (SAN/NAS)
 Computing/server applications
 GPS
 Portable POS systems
 Low cost serial interfaces
35

36. Using the ADI High Performance
Servo FMC Platform with Xilinx
FPGAs and Simulink
Section 6
36

37. ADI High Performance Servo Development
Platform
Target FPGA Platforms
 Xilinx Virtex FPGA platforms
 Xilinx Kintex FPGA platforms
 Xilinx Zynq FPGA platforms
Control Algorithms
 Simulink models for controller ready for code
generation using HDL Coder™ from MathWorks
and Xilinx System Generator
 Reference design showing BLDC motor speed
control
 Reference design showing BLDC motor speed
and torque control
Simulation and Monitoring
 Controller simulation and tuning in Simulink
 ChipScope™ interface for internal signals
monitoring
37

38. Motor Control Reference Design FPGA Blocks
 Motor Controller generated from Simulink
 6 State Motor Driver
 SINC3 Filters for current and voltage
measurement
 BEMF position detector
 Hall position detector
 ChipScope blocks
38

39. Speed Control Reference Designs
Speed Control Reference Design
 Target motor: BLDC
 Speed control using Hall sensors
 Sensorless speed control using
BEMF
 Simulink controller model
 ChipScope interface for internal
signals monitoring
Implementation Flow
39
BLDC
PID
Controller
6 State
Motor Driver
Speed
Computation
PWM
PositionSpeed
Reference
Speed
+
-
Design and Tune
the
Motor Controller
in
Simulink
using the
Xilinx Blockset
Generate the HDL Netlist
for the
Simulink Motor Controller
using
Xilinx System Generator
Integrate
the
Motor Controller HDL Netlist
in the
Speed Control Reference
Design

40. Simulink Speed Controller
40
Speed Computation
PID Controller
Edge Detection

41. Simulink Speed Controller
41
Speed Computation
PID Controller
Edge Detection

42. Simulink Speed Controller
42

43. Motor Control Reference Designs
Speed and Torque Control
Reference Design
 Target motor: BLDC
 Speed and torque control
 Simulink controller model
 ChipScope interface for
internal signals monitoring
Implementation Flow
43
BLDC
PI Speed
Controller
6 State
Motor Driver
Speed
Computation
Current
Reference
PositionSpeed
Speed
Reference
+
-
PID Current
Controller
PWM
Current
Computation
Total Current
Measurement
Total
Current
+ -
Design and Tune
the
Motor Controller
in
Simulink
using
Simulink Native Blocks
Generate the HDL Netlist
for the
Simulink Motor Controller
using
Xilinx System Generator
Integrate
the
Motor Controller HDL Netlist
in the
Speed and Torque Control
Reference Design
Generate the HDL code
for the
Motor Controller
using
HDL Coder
Replace in the Simulink model
the Motor Controller
with
Xilinx Black Boxes
containing the
HDL generated by
HDL Coder

44. Simulink Speed and Torque Controller
44

45. Simulink Speed and Torque Controller
45
Speed Computation
PI Speed Controller
Current Computation
PID Torque Controller

46. Simulink Speed and Torque Controller
46

47. Simulink Speed and Torque Controller
47

48. Conclusions
The ADI high performance servo development platform showcases
a full motor control solution that shows how to integrate all the
necessary hardware components for efficient motor control in one
system
The FPGA interfacing capabilities provide a high degree of flexibility
in developing high performance motor control algorithms
By using the MathWorks simulation and development tools, high
performance control algorithms can be developed and simulated on
the PC and transferred directly into the FPGA
The ADI motor control reference designs provide a starting point for
developing enhanced motor control algorithms using MathWorks
and Xilinx FPGAs
48

49. Tweet it out! @ADI_News #ADIDC13
Design Resources Covered in This Session
Ask technical questions and exchange ideas online in our
EngineerZone™ Support Community
 Choose a technology area from the homepage:
 ez.analog.com
 Access the Design Conference community here:
 www.analog.com/DC13community
Download the motor control reference designs and documentation
from the ADI wiki
 wiki.analog.com
49