Don’t Compromise: Don’t Compromise: DSP Controllers Solve Your DSP Controllers Solve Your Embedded Control Design Embedded Control Design

Challenges Challenges

Presentation begins live from DallasPresentation begins live from DallasOctober 31, 7:00 a.m. and 11:00 a.m.October 31, 7:00 a.m. and 11:00 a.m.

Central Standard Time (CST)Central Standard Time (CST)C2000, C24x, C28x, F28x, Code Composer, and eXpressDSP are trademarks of Texas Instruments Incorporated.eZdsp is a trademark of Spectrum Digital.

Don’t Compromise: Don’t Compromise: DSP Controllers Solve DSP Controllers Solve

Your Embedded Your Embedded Control Design Control Design

ChallengesChallenges

1 Copyright © 2001 Texas Instruments. All rights reserved.

C2000, C24x, C28x, F28x, Code Composer, and eXpressDSP are trademarks of Texas Instruments Incorporated.eZdsp is a trademark of Spectrum Digital.

AgendaAgenda

A quick look at a typical control system

Challenges and constraints faced by the embedded control designer

The ideal solution: Achieving the goal without compromise

The advantages of DSP in control applications

System examples

Question and Answer session2

The Four Major Components of a The Four Major Components of a Typical Control SystemTypical Control System

ControllerAnalog

orDigital

Actuator

Sensor

Plant

Thermo-electric coolers (TEC) Printers/Copiers Handheld power tools Motor drives Fuel pumps Electronic power steering (EPS) Uninterruptible power supplies (UPS) Intelligent sensors

DVD players Industrial automation HVAC compressors Electronic cooling systems Fluorescent light ballasts Toys (e.g. model trains, dolls) Refrigeration HVAC blowers

Examples of control applications

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Analog Controller Digital Controller

+ High bandwidth High resolution Easy to understand/use “Relatively” low cost

Insensitive to environment (temp, drift…) High reliability Software programmable/flexible solution Precise/predictable behavior Advanced control possible (non-linear,

multi-variable) Can perform multiple loops and “other”

functions Component drift and

aging/unstable Hardwired/not flexible Limited to classical

control theory only Large parts count for

complex systems

Bandwidth limitations (sampling loop) Numerical problems (quantization,

rounding…) AD/DA boundary (resolution, speed,

cost) CPU performance limitations System cost

?

Digital Control AdvantagesDigital Control AdvantagesOutweigh AnalogOutweigh Analog

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Bandwidth limitations (sampling loop)

CPU performance limitations

Numerical problems (quantization, rounding…)

AD/DA boundary(resolution, speed, cost)

System cost

40- and 150-MIPS DSP

16- and 32-bit math

10-/12-bit high-speed ADCsHigh-speed/high-resolution PWMs

Increased on-chip integration

Today’s DSP Controllers (+)Industry Concerns (-)

Today’s DSPs Solve Embedded Today’s DSPs Solve Embedded Control Design ConcernsControl Design Concerns

5

DAC

ADC

DSP

011010110010110111010010100111

“Plant”

“Digital/Real World”Boundary

The “No Compromise” Topology!The “No Compromise” Topology!

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DAC

ADC

DSP

“ProcessingEngine”

Outputs Power inverter Solenoids Actuators Switchers

Current Voltage Position Speed Temperature Pressure

Inputs

Resolution Linearity/Accuracy Sampling rate (speed) HV isolation

“DA

C”

“AD

C”

ContinuallyImproving

specs!

AD/DA Boundary

Empowering the Digital DomainEmpowering the Digital Domain

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ADC (12 bits/60nS) PWMs (6.7nS) CAP/QEP I/Os UART/SPI/CAN/McBSP

Cost($US)

Performance

(MIPS)

E14(1989)

F240(1995)

C242(1995)

LC2401(2001)

$20

$13

$5

$2-3

6 20 40 150

F281x(2001/2)

PWMs CAP I/Os UART

ADC (10 bits/6S/0.8S)

PWMs (50nS) CAP/QEP I/Os UART/SPI/CAN

ADC(10 bits/400nS)

PWMs (25nS) CAP/QEP I/Os UART/SPI/CAN

400

LF2403(2001)

$6-8

Peripheral Integration

DSP Controllers – TrendsDSP Controllers – Trends

LowCost

HighMIPS

8

PWM Effective Resolution (# Bits)

PWM

“The Power DAC”

+ DC_BUS

PWM2

InverterPWM1

Pulse Width Modulation (PWM) – Pulse Width Modulation (PWM) – The “Power DAC”The “Power DAC”

PWM is the only real technique to control high-powered “actuators.”

“DA” resolution is dependent only on digital clocking speed. Power switching elements (MOSFETs, IGBTs, Triacs)

continuously improving in frequency, switching losses, high voltage, and current capabilities.

Switching frequencies above the audible range now very easy to achieve.

PWM(KHz) 20 30 40 150

10 11.0 11.6 12.0 13.920 10.0 10.6 11.0 12.930 9.4 10.0 10.4 12.350 8.6 9.2 9.6 11.6

System Clock (MHz)

9

ADC

“The Classical A/D Converter”PWM2

Signal conditioning

ADC_IN

PWM1

F/C24xx DSP 10-bit resolution 2 Msamples/sec 16 analog channels 16-state

autosequencer 16-deep result

buffer

AD

C

CurrentIa

F28xx DSP 12-bit resolution 16.7 Msamples/sec 16 analog channels Dual sample & hold 16-state

autosequencer 16-deep result

buffer

The Classical A/D ConverterThe Classical A/D Converter

Volts

Va

10

Capture

“The Time ADC”

Sensor

t1

t2

t

CAPx

Speed Meas. - Effective # Bits

Speed

Capture – The “Capture – The “ Time ADC” Time ADC”

Ideal A/D interface to rotating/moving machines or mechanisms

Time-based measurement ideal way to digitize period, speed, acceleration

Measurement resolution is dependent only on digital clocking speed (i.e. time base)

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“The Position ADC”

QEP

Example: 1000 QEP pulses = 360°

Position

12341000

Index

A

B

Counterclock

QEPx

Quadrature Encoder Pulse (QEP) – Quadrature Encoder Pulse (QEP) – The “Position ADC”The “Position ADC”

Ideal A/D interface to rotating/moving machines or mechanisms

Quadrature encoder ideal way to digitize position, period, speed, acceleration

Position Meas. - Effective # Bits

Encoder Position(# Lines) (# bits)

500 11.01000 12.02000 13.04000 14.0

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DAC

ADC

Control Algorithm Examples Space vector modulation (SVM) Field-oriented (vector) control (FOC) Sensorless flux vector position estimation Sensorless speed estimation Extended Kalman estimator (EKF) Sliding mode observer (SMO) Model Reference Adaptive System (MRAS) Non-linear control techniques Online motor parameter self tuning Precision PID (32-bit) control FFT/FIR/IIR/Matrix functions

MIPS Drive “Mathematical Freedom!”MIPS Drive “Mathematical Freedom!”

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MIPS Drive “Friendly Modular Software!”MIPS Drive “Friendly Modular Software!”

FIRFilter

FFT128/256

SineGen

MathFunc

MathFunc

PIDControl

SpaceVec Mod

SlidingMode

Observer

FluxEstimator

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General ControlPID 16- and 32-bit precisionADC software drivers PWM control software drivers 2nd order plantGPIO software driversSignal generators (sine, ramp…)Period and frequency

measurement

Math FunctionsSine/Cosine/ArcTanSqrt/Log/Ln/InvFFT real – 128/256/512 FFT complex – 128/256/512 Filters FIR (order N)Filters IIR (order N bi-quads)

Communications SupportSPI (hardware) and VSPI

(software) driversEEPROM interface driver

(SPI format)SCI (UART) packet driver I2C (slave + master)

software driverEEPROM interface driver

(I2C format)CAN low-level driver

Foundation Software Libraries for the Foundation Software Libraries for the General MarketGeneral Market

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Digital Motor Control (DMC)Sensorless and sensored solutions:AC Induction (ACI) motors scalar

and vector controlPermanent Magnet Synchronous

Motors (PMSM) vector controlBrushLess DC (BLDC) motors

trapezoidal controlSwitched Reluctance (SR) motors

Power ConversionFour-stage uninterruptible

power supply (UPS)Power factor correction

Optical Networks (ONet)Collection of

communications modulesCollection of control and

peripheral drivers

Foundation Software Libraries for Foundation Software Libraries for Specific Technology SegmentsSpecific Technology Segments

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LF2401A

MIPS/Size/Cost = “Sweet Spot”MIPS/Size/Cost = “Sweet Spot”

MIPS: 40

Size: 7 mm x 7 mm(5/16” x 5/16”)

Cost: US $2 (ROM) US $5 (Flash)

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Example 1 – “Intelligent Cooling”Example 1 – “Intelligent Cooling”

Ra

ck F

an

EquipmentRacks

18

PMSM3 phase

DSP Software SolutionPosition estimation

(sliding mode observer)Space vector PWMCoordinate transformsPhase current

reconstructionCurrent PID loop x 2Speed PID loopTemperature loop (optional)Communications protocol

LC2401ADSP

PW

MA

DC

PWM

ADCC

OM

MS

Network

Signalconditioning

Example 1 – “Intelligent Cooling”Example 1 – “Intelligent Cooling”

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Example 2 – “Power Tools”Example 2 – “Power Tools”

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BrushedDC

motorLC2401ADSP

PW

MA

DC

PWM

ADCI/O

DSP Software SolutionSpeed estimation

N point FFTFiltering FIR/IIR“Other” math functions

Phase current measurements

Current PID loopSpeed PID loop

FWD

REV

Directioncontrol

Speedcontrol

I/O

Signalconditioning

Example 2 – Power ToolsExample 2 – Power Tools

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Example 3 – Uninterruptible Power Example 3 – Uninterruptible Power Supply (UPS)Supply (UPS)

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V

II

I

VV

V

V

HiV

LoV

HiV

LF24xxor

F28xxDSP

PW

MA

DC

PWM

ADC

I/O

DSP Software SolutionCurrent/Voltage PID loopsVoltage boost controlBattery charging controlLine voltage synthesis +

regulationLine monitoring and switch

over controlPower factor correction

I/O

Example 3 – UPSExample 3 – UPS

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Example 4 – High-End Multi-Axis ControlExample 4 – High-End Multi-Axis Control

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PWMF28xxDSP

“DA

C”

“AD

C”

ADC

“CO

MM

S”

”I/O

”

“Network”

“User Interface”

DSP Software SolutionMultiple system (“algorithm”) instantiationMulti-tasking/multi-threadingLow interrupt latency/Fast context save and restoreHigh-level network protocols

CAN (deviceNet, CANopen,…) and Ethernet (TCP/IP)Sensored control: 30 ~ 60 MIPS (3 axis)Sensorless hi-end control: 60 ~ 90 MIPS (3 axis)

Example 4 – High-End Multi-Axis ControlExample 4 – High-End Multi-Axis Control

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Example 5 – Optical Networks (ONet)Example 5 – Optical Networks (ONet) Tunable Lasers Tunable Lasers

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Fiber

Laser

Heater

Peltier element LPF

H-Bridge Amp

F2810DSP

CO

MM

SA

DC

PW

MIN_L

IN_R

OUT_ROUT_L

Thermistor

Vsupply

LPF

Temp.

Intensity

PwrLPF

Photodiode

Laser diode

“Network”

Linear Amp

DSP Software Solution12-bit ADC (14 bits

with operating system) High-resolution PWMs

provide 12-bit DACs @ 40 KHz

Efficient 32-bit precision-control loops

Full C/C++ implementation

ADC

Example 5 – ONet Tunable LasersExample 5 – ONet Tunable Lasers

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ConclusionConclusion

DSP controller advancements (performance/price/ integration) have made digital control the preferred solution over legacy analog approaches.

The DSP centric topology with A-to-D and D-to-A interface to the real world is a simple yet very powerful solution to most control problems.

Continually improving MIPS and A-to-D and D-to-A fidelity is giving designers more freedom without compromise.

The performance/price/size “sweet-spot” is here now and it’s only going to get better!

DSP controllers are and will continue to be deployed in many end equipments, including the most cost-sensitive ones.

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Get Started Today with Digital Signal Get Started Today with Digital Signal Processors from Texas InstrumentsProcessors from Texas Instruments

Visit http://focus.ti.com/docs/general/symlink.jhtml?name=c2000promo1 for details on the following.

Download the complimentary C2000™ DSP Foundation Software Library. This collection of Digital Motor Control software modules allows you to rapidly build or customize your own systems.

DSP Starter Kits (DSKs) are a low-cost, easy-to-use development tool that allows you to explore the C2000 DSP architecture and start designing today.

Comprehensive technical documentation including application notes, data sheets, and more.

Order device samples. Free online training.

For further information, search TI’s DSP KnowledgeBase: www.ti.com/sc/dspkbaseoct

Check out the latest digital signal processing news in TI’s DSP eNewsletter: eTech Innovations, Digital Signal Processing Edition at www.ti.com/sc/etechdsppromo6

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