Drives & Control June 2003 A. Jansen 1 Brushless DC Motor Control with C868 and CAPCOM6.

Drives & Control

June 2003

A. Jansen

1

Brushless DC Motor Control

withC868

and CAPCOM6

Drives & Control

June 2003

A. Jansen

2

Agenda

Basics of a BLDC MotorTopologyBLDC Motor with Hall SensorsBLDC Motor with Hardware

BEMF-DetectionBLDC Motor Sensor less Control

Switching Pattern for Driving a BLDC

How to use the CAPCOM6E for a BLDC

Introduction CAPCOM6E for BLDC purpose

CAPCOM6E & ADC

Drives & Control

June 2003

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3

Electrical Motor Types

ElectricMotor types

ElectricMotor types

ACAC

AsynchronousAsynchronous SynchronousSynchronous

InductionInduction

StepperStepperSynchronousSynchronousPMSMPMSM Switched Rel.Switched Rel.

DCDC

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June 2003

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BLDCBasics

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June 2003

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5

Basics of a BLDC Motor

DC Motor with 3 Brushes

VW

UU

VW

+

-

3-Phase Brush-less DC Motor

According to the theory of DC machine, the motor rotational speed can be written as follows:

N = ( Ud - I R ) / (Ke )While,

“N” stands for the motor rotational speed“Ud” stands for the DC voltage applied to the motor windings“R” is the pure resistance of the winding while “I” stands for the winding current “Ke” is the magnet coefficient while “” stands for the motor magnetic flux

From the above formula, there are two methods to change the speed of DC motor: One is to change the DC voltage of the motor windings (Ud), the other one is to change the magnetic flux of the motor (). As the BLDC motor has permanent magnet rotor, only the first method can be used in practical application. The principal of generating variable DC voltage is to use PWM for chopping: change the duty cycle of the PWM voltage, proportionally change the DC voltage.

N

S

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How an Inverter Turns a BLDC (1)

C+

B-

11

0

A’

B’

B C

C’

A

NS

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C+

B-

11

0

A’

B’

B C

C’

A

NS

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C+

B-

A’

B’

B C

C’

A

11>>0

0

N

S

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C+

A-

10

0

A’

B’

B C

C’

A

N

S

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B+

A-

A’

B’

B C

C’

A

N

S

1>>00

0

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June 2003

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11


B+

A-

A’

B’

B C

C’

A

NS

1>>00

0

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June 2003

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BLDC with Hall Sensors – Switching Pattern

Typical Switching Pattern for a BLDC Hall Sequence depends on motor construction Output pattern levels depends on inverter topology

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June 2003

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BLDC withHall Sensors

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June 2003

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BLDC with Hall Sensors -- Topology

Typical Circuit Block Diagram Hall Sensors detect the position Over current protection and control via ADC

Hall Sensor

C868

+-

HV

Driver

V+

MotorCC60COUT60

CC61COUT61

CC62COUT62C

TR

AP

CC

PO

S2

CC

PO

S1

CC

PO

S0

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Block Diagram CAPCOM6E for BLDC Usage

channel 0

channel 1

channel 2

T12

capture/compare input / output control

CC

62

CO

UT

62

CC

61

CO

UT

61

CC

60

CO

UT

60

CT

RA

P

channel 3T13

CC

PO

S0

222

compare

capture

trapcontrol

1

port control

CC

PO

S1

CC

PO

S2

3

noisefilter

compare multi-channel control

compare

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H ardware N oiseSuppression

ch0 ge ts capturedva lue fo r act. speed

ch1 com parefor phase de lay

ch2 com parefor tim eout

CC6x

act. speedCC60

phase delayCC61

timeoutCC62

COUT6y

110001CCPOS2

CCPOS0 1 1 1 0 0 0

CCPOS1 0 0 1 1 1 1

C aptureEvent

R esets T12

Usage of CAPCOM6E to Control a BLDC (1)

BEMF-Detection/Hall Signals

HW-noise filter on CCPOSx inputs (BEMF-signals)

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CC6x

act. speedCC60

phase delayCC61

timeoutCC62

COUT6y

110001CCPOS2

CCPOS0 1 1 1 0 0 0

CCPOS1 0 0 1 1 1 1

C aptureEvent

R esets T12




automatic reset of T12 with interrupt

actual speed by capture ch0

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CC6x

act. speedCC60

phase delayCC61

timeoutCC62

COUT6y

110001CCPOS2

CCPOS0 1 1 1 0 0 0

CCPOS1 0 0 1 1 1 1

C aptureEvent

R esets T12






phase delay function on ch1

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CC6x

act. speedCC60

phase delayCC61

timeoutCC62

COUT6y

110001CCPOS2

CCPOS0 1 1 1 0 0 0

CCPOS1 0 0 1 1 1 1

C aptureEvent

R esets T12






phase delay function on ch1

time out function on ch2

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June 2003

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Usage of CAPCOM6E – Hall Sensor Mode (1)

Hall n n+1

Hall n+1 n+2

0 0

0 0

1

1

0

1 0H2

H1

H0

? ?startDead Time Counterafter edge detection

CCPOSx Inputs for Hallsensor Interface

MCMOUTSH / MCMOUTSL SW programmable state machine

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June 2003

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Hall n n+1

Hall n+1 n+2

0 0

0 0

1

1

0

1 0H2

H1

H0

? ?noise Correct

expectedHall Event

comparevalid level

afterDTC count down

CCPOSx Inputs edge detection triggers Dead Time

Counter

MCMOUTSH / MCMOUTSL compare CCPOSx level with programmed

value

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Hall n+1 n+2

Hall n+1 n+2

0 0

0 0

1

1

0

1 0H2

H1

H0

? !noise Correct

expectedHall Event

setCHE-flag

CCPOSx Inputs MCMOUTSH / MCMOUTSL switch to next state on valid edge by

hardware

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prepare next state

Hall n+1 n+2

Hall n+2 n+3

0 0

0 0

1

1

0

1 0H2

H1

H0

? ?

wait onedge

CCPOSx Inputs wait on edge

MCMOUTSH / MCMOUTSL prepare next state by software

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June 2003

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Usage of CAPCOM6E – Modulation Control (some Choices)

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

1

1

A-1

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

1

1

A-

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

0

1

A-

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

1

A-

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

1

0

A-1

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June 2003

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Usage of CAPCOM6E – Generate the PWM Pattern for BLDC

T12.COUT2

MODT13out

MCMOUTH.5

CTRAP#

1

0>0>0>1>1>0>0

1

T12.CC2

MODT13out

MCMOUTH.4

CTRAP#

1

1>1>0>0>0>0>1

1

T12.COUT1

MODT13out

MCMOUTH.3

CTRAP#

1

1>0>0>0>0>1>1

1

T12.CC1

MODT13out

MCMOUTH.2

CTRAP#

1

0>0>1>1>0>0>0

1

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

0>1>1>0>0>0>0

1

T12.CC0

MODT13out

MCMOUTH.0

CTRAP#

1

0>0>0>0>1>1>0

1

1

1

C+

B-

C-

B+

A+

A-

H2

H1

H0

1

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T12.COUT2

MODT13out

MCMOUTH.5

CTRAP#

1

0>0>0>1>1>0>0

1

T12.CC2

MODT13out

MCMOUTH.4

CTRAP#

1

1>1>0>0>0>0>1

1

T12.COUT1

MODT13out

MCMOUTH.3

CTRAP#

1

1>0>0>0>0>1>1

1

T12.CC1

MODT13out

MCMOUTH.2

CTRAP#

1

0>0>1>1>0>0>0

1

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

0>1>1>0>0>0>0

1

T12.CC0

MODT13out

MCMOUTH.0

CTRAP#

1

0>0>0>0>1>1>0

1

1

1

C+

B-

C-

B+

A+

A-

H2

H1

H0

1

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T12.COUT2

MODT13out

MCMOUTH.5

CTRAP#

1

0>0>0>1>1>0>0

1

T12.CC2

MODT13out

MCMOUTH.4

CTRAP#

1

1>1>0>0>0>0>1

1

T12.COUT1

MODT13out

MCMOUTH.3

CTRAP#

1

1>0>0>0>0>1>1

1

T12.CC1

MODT13out

MCMOUTH.2

CTRAP#

1

0>0>1>1>0>0>0

1

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

0>1>1>0>0>0>0

1

T12.CC0

MODT13out

MCMOUTH.0

CTRAP#

1

0>0>0>0>1>1>0

1

1

1

C+

B-

C-

B+

A+

A-

H2

H1

H0

1

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T12.COUT2

MODT13out

MCMOUTH.5

CTRAP#

1

0>0>0>1>1>0>0

1

T12.CC2

MODT13out

MCMOUTH.4

CTRAP#

1

1>1>0>0>0>0>1

1

T12.COUT1

MODT13out

MCMOUTH.3

CTRAP#

1

1>0>0>0>0>1>1

1

T12.CC1

MODT13out

MCMOUTH.2

CTRAP#

1

0>0>1>1>0>0>0

1

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

0>1>1>0>0>0>0

1

T12.CC0

MODT13out

MCMOUTH.0

CTRAP#

1

0>0>0>0>1>1>0

1

1

1

C+

B-

C-

B+

A+

A-

H2

H1

H0

1

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T12.COUT2

MODT13out

MCMOUTH.5

CTRAP#

1

0>0>0>1>1>0>0

1

T12.CC2

MODT13out

MCMOUTH.4

CTRAP#

1

1

T12.COUT1

MODT13out

MCMOUTH.3

CTRAP#

1

1>0>0>0>0>1>1

1

T12.CC1

MODT13out

MCMOUTH.2

CTRAP#

1

0>0>1>1>0>0>0

1

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

0>1>1>0>0>0>0

1

T12.CC0

MODT13out

MCMOUTH.0

CTRAP#

1

0>0>0>0>1>1>0

1

1

1

C+

B-

C-

B+

A+

A-

H2

H1

H0

1

1>1>0>0>0>0>1

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T12.COUT2

MODT13out

MCMOUTH.5

CTRAP#

1

0>0>0>1>1>0>0

1

T12.CC2

MODT13out

MCMOUTH.4

CTRAP#

1

1

T12.COUT1

MODT13out

MCMOUTH.3

CTRAP#

1

1>0>0>0>0>1>1

1

T12.CC1

MODT13out

MCMOUTH.2

CTRAP#

1

0>0>1>1>0>0>0

1

T12.COUT0

MODT13out

MCMOUTH.1

CTRAP#

1

0>1>1>0>0>0>0

1

T12.CC0

MODT13out

MCMOUTH.0

CTRAP#

1

0>0>0>0>1>1>0

1

1

1

C+

B-

C-

B+

A+

A-

H2

H1

H0

1

1>1>0>0>0>0>1

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Usage of CAPCOM6E – Modulation and Synchronization

CorrectHall Event

MCMP

MCMPS

to modulationselection

6

write by software

6T12pm

T13pm

T12c1cm

T13zm

Flag

T12zm

direct

T12om

SW-Triggerno action

Reset

MCMOUTSL

MCMOUTL

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CorrectHall Event

MCMP

MCMPS


6

write by software

6T12pm

T13pm

T12c1cm

T13zm

Flag

T12zm

direct

T12om

SW-Triggerno action

Reset

MCMOUTSL

MCMOUTL

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CorrectHall Event

MCMP

MCMPS


6

write by software

6T12pm

T13pm

T12c1cm

T13zm

Flag

T12zm

direct

T12om

SW-Triggerno action

Reset

MCMOUTSL

MCMOUTL

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CorrectHall Event

MCMP

MCMPS


6

write by software

6T12pm

T13pm

T12c1cm

T13zm

Flag

T12zm

direct

T12om

SW-Triggerno action

Reset

MCMOUTSL

MCMOUTL

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0 0 0

1 1 0 1 0 0

1 0 00 1 0

0 1 1 0 0 0

0 1 0

MCMOUTSL

MCMOUTL

MCMOUTSH

MCMOUTH

C+

B-

11

0

A’

B’

B C

C’

A

N

S

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0 0 0

1 0 0 0 0 0

1 0 00 1 0

0 1 1 0 0 0

0 1 0

MCMOUTSL

MCMOUTL

MCMOUTSH

MCMOUTH

C+

B-

A’

B’

B C

C’

A

11>>0

0

N

S

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0 0 1

1 0 0 0 0 0

0 0 00 1 0

0 1 0 0 1 0

0 1 0

MCMOUTSL

MCMOUTL

MCMOUTSH

MCMOUTH

C+

A-

10

0

A’

B’

B C

C’

A

N

S

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0 0 1

0 0 0 0 0 1

0 0 00 0 0

0 1 0 0 1 0

0 1 1

MCMOUTSL

MCMOUTL

MCMOUTSH

MCMOUTH

B+

A-

A’

B’

B C

C’

A

N

S

1>>00

0

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BLDCSensor

less

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BLDC in Theory – Back Electro Magnetic Force

Theory UP = (R x i) + (L x di/dt) + eP

where"UP" stands for phase voltage"R" stands for winding resistance"i" stands for actual phase current"L" stands for phase inductance"di/dt" stands for changment of phase current over time"eP" stands for electromagnetic voltage caused by

magnet

whilei = 0 and di/dt = 0:UP = eP

by measuring UP

a position detectionis possible

iavai

30°

ibvbi

120°

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BLDC in Reality (1) – BEMF vs. Current

iav

ai

Real BEMF Voltage and Current: shape depends on magnets, motor speed, voltage

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June 2003

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BLDC in Reality (2a) – BEMF vs. Current

Zoom In: BEMF is only visible at active switching

PhaseCurrent

BEMFVoltage

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BLDC in Reality (2b) – BEMF vs. Current

Current Commutation in a Coil Freewheeling diode conducts

PhaseCurrent

BEMFVoltage

V+

GND

CurrentFlow

Motor

V+

GND

Current FlowFreewheeling

Diode

Motor

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BLDC in Reality (3) – All Important Signals

PhaseCurrent

BEMFVoltage

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BLDC Sensor less with Hardware BEMF-Detection

Typical Circuit Block Diagram Comparators and RC-Filter detect the BEMF zero crossing

for position detection

C868

RCFilter

virtualStar

-+

-+

-+

+-

HV

Driver

V+

MotorCC60COUT60

CC61COUT61

CC62COUT62C

TR

AP

CC

PO

S2

CC

PO

S1

CC

PO

S0

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BLDC Sensor less Using ADC

Typical Circuit Block DiagramUse simple resistor divider and ADC for position detection

C868

+-

HV

Driver

V+

MotorCC60COUT60

CC61COUT61

CC62COUT62C

TR

AP

AN

2

AN

1

AN

0

BEMFDetection

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CAPCOM6E & ADC

Synchronize ADC on T13 T13 period match can trigger the ADC equidistant sampling of analog signals exact timing guaranteed by hardware no timing jitter due to software delays

f(n-1)f(n) f(n+1)

f(n+2)

conversionchannel 0

T13

analogsignal

ADC

start samplingby hardware

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CAPCOM6E & ADC

Synchronize T13 on T12 T13 performs delay for

stable measurement T13 period match

triggers ADC Useful for Current

Measurement E.g. induction machine

Compare value

T12

T13

CC6x

PhaseCurrent x

synchronizeT13 on T12cm

Start ADC whensignal is stable after aprogrammable delay

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CAPCOM6E & ADC

T13PM triggers ADC Delay between T13PM

and high voltage switching event due to driving circuit

Useful for Voltage or Current Measurement E.g. BEMF detection Sample shortly before

power device is switched off (BEMF is noise free)

BEMFsignal

IGBTdrainvolt.

CC6x

T13

Modulation forBlock-Commutation

Delay due toIGBT driving circuit

IGBT’s gate signal

Voltage signal atcurrentless phase

for position detection

Start ADC sampling

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CAPCOM6E & ADC

T13PM triggers ADC Delay between T13PM and

high voltage switching event due to driving circuit

Useful for Voltage or Current Measurement E.g. Current in DC link

path Sample shortly before

power device is switched off (current is noise free) IGBT

drainvolt.

CC6x

T13

Modulation forBlock-Commutation

Delay due toIGBT driving circuit

IGBT’s gate signal

DC LinkCurrent

Start ADC sampling

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BLDC Sensor less Using ADC

T13 used forModulationADC trigger

T12 used for Phase delay

Software (for 60° sector)

With every T13PMthe BEMF voltage is sampled and compared to a BEMF-wave table

When crossing a limit the software generates a CHE-event (1)

Speed reference is captured and phase delay for T12ch1 is calculated

At T12ch1 the pattern for the next sector is switched (2)

BEMFVoltagePhase

C

T13

T12

CurrentPhase C

CurrentPhase A

MeasureBEMF-Voltage

(Phase C)

MeasureDC-Link Current

(Phase A)

MeasureVoltage(Phase

B)

1 2

AnalogCompareValue

CompareValueT12_ch1

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BLDC Sensor less with Current Control

T13 used forModulationADC trigger

T12 used for Phase delay

Software (for 60° sector)

With every T13PM the ADC alternatively samples BEMF voltage Phase current

The current set value can be controlled by adjusting the PWM duty cycle

BEMFVoltagePhase

C

T13

T12

CurrentPhase C

CurrentPhase A

MeasureDC-LinkCurrent

(Phase A)

MeasureBEMF

Voltage(Phase C)

MeasureDC-Link Current

(Phase A)

MeasureBEMF

Voltage(Phase

B)

MeasureDC-LinkCurrent

(Phase C)

1 2

CompareValueT12_ch1

AnalogCompareValue

ControlCurrent Value

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BLDC Sensor less Scope Shots

Port pin toggles when BEMF is below limit

BEMFVoltage

PhaseCurrent

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Application: Line powered Industrial Drives Power: 750 W Current: max. 5 A AC Input Voltage: 110 to 264 VAC

Features: 8-bit MCU: C868 with on-chip 8 kB SRAM, with 8-

bit ADC and powerful PWM module CoolSet: TDA61831G instead of a transformer

for 12V supply 6 rugged IGBT DuoPacks EEPROM: 8 kB to store program + stand alone

boot option Optically Isolated Serial Interface to PC for SW

development + boot from PC option Protection: shut down protection for over current

and over temperature Extension for alternative MCU like XC164 or

TC1775 SW environment: Keil Compiler + Debugger or

Mini Debugger (free software) Board can be used for current/torque or speed

control Supports Hall-Effect sensors or sensor-less

control

High Voltage 3-Phase Brushless DC / Induction MotorReference Design and Development Kit

Drives & Control

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Low Voltage 3-Phase Brushless DC / Induction MotorReference Design and Development Kit

Application: Industrial & Automotive Drives Power: 1.2 kW Current: max. 50 A Voltage: 12 - 24 V DC

Features: 8-bit MCU: C868 with on-chip 8 kB SRAM, with 8-

bit ADC and powerful PWM module 3-Phase Bridge Driver: TLE6280G 6 OptiMOS MOSFETs EEPROM: 8 kB to store program + stand alone

boot option RS232: Interface to PC for SW development +

boot from PC option Protection: shut down protection for over current

and over temperature Extension for alternative MCU like XC164 SW environment: Keil Compiler + Debugger or

Mini Debugger (free software) Board can be used for current/torque or speed

control Supports Hall-Effect sensors or sensor-less

control

Drives & Control June 2003 A. Jansen 1 Brushless DC Motor Control with C868 and CAPCOM6.

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