NXP Semiconductors MC56F8013 User manual

56F8000
16-bit Hybrid Controllers
freescale.com
3-Phase BLDC Motor Control
with Hall Sensors Using the
MC56F8013
Targeting User Guide
56F8013BLDCUG
Rev. 1
11/2005

TABLE OF CONTENTS
Table of Contents, Rev. 1
Freescale Semiconductor i
Preliminary
About This Book
Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preface-v
Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preface-v
Suggested Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preface-v
Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preface-vi
Definitions, Acronyms, and Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preface-vii
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preface-vii
Chapter 1
Introduction
1.1 Application Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Chapter 2
System Description
2.1 Application Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2 Hardware Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3 Software Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.3.1 Data Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Chapter 3
Setting Up the Application
3.1 Required Parts and Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Chapter 4
Running the Application
4.1 BLDC with Hall Sensor Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

3-Phase BLDC Motor Control, Rev. 1
ii Freescale Semiconductor
Preliminary

LIST OF FIGURES
List of Figures, Rev. 1
Freescale Semiconductor iii
Preliminary
2-2 System Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2-3 Main Data Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2-4 Speed Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
3-1 56F8000 Motor Control Daughter Card and 56F8013 Demonstration Board . . . . . . . . 3-1

3-Phase BLDC Motor Control, Rev. 1
iv Freescale Semiconductor
Preliminary

Preface, Rev. 1
Freescale Semiconductor v
Preliminary
About This Book
This manual describes the applications for 3-Phase BLDC motor control with Hall sensors using
the 56F8013 device.
Audience
This document targets software developers using 3-Phase BLDC motor control for the 56F8013
processor.
Organization
•Chapter 1, Introduction—provides a brief overview of this document
•Chapter 2, System Description—describes the theory of BLDC motor control with Hall
sensors for the 56F8013 processor
•Chapter 3, Setting Up the Application—explains how to set up the application
•Chapter 4, Running the Application—describes how the BLDC with Hall Sensor
application operates
Suggested Reading
We recommend that you have a copy of the following references:
•56F8013 Technical Data, MC56F8013
•56F8013 Motor Control Demonstration System using the 56F8013 Demonstration Board
User Guide, 56F8013MCSUG
•3-Phase BLDC Motor Control with Hall Sensors using 56800/E Digital Signal Controllers,
AN1916
•56F8000 Peripheral Reference Manual, MC56F8000RM
•Inside CodeWarrior: Core Tools, Metrowerks Corp.

3-Phase BLDC Motor Control, Rev. 1
vi Freescale Semiconductor
Preliminary
Conventions
This document uses the following notational conventions:
Typeface,
Symbol or Term Meaning Examples
Courier
Monospaced
Type
Code examples //Process command for line flash
Italic Directory names,
project names,
calls,
functions,
statements,
procedures,
routines,
arguments,
file names,
applications,
variables,
directives,
code snippets
in text
...and contains these core directories:
applications contains applications software...
...CodeWarrior project, 3des.mcp is...
...the pConfig argument....
...defined in the C header file, aec.h....
Bold Reference sources,
paths,
emphasis
...refer to the Targeting DSP56F80x Platform
manual....
...see: C:\Program Files\Motorola\help\tutorials
Blue Text Linkable on-line ...refer to Chapter 7, License....
Number Any number is consid-
ered a positive value,
unless preceded by a
minus symbol to signify
a negative value
3V
-10
DES-1
ALL CAPITAL
LETTERS
# defines/
defined constants
# define INCLUDE_STACK_CHECK
Brackets [...] Function keys ...by pressing function key [F7]
Quotation
marks, “...”
Returned messages ...the message, “Test Passed” is displayed....
...if unsuccessful for any reason, it will return
“NULL”...

Preface, Rev. 1
Freescale Semiconductor vii
Preliminary
Definitions, Acronyms, and Abbreviations
The following list defines the acronyms and abbreviations used in this document. As this template
develops, this list will be generated from the document. As we develop more group resources, these
acronyms will be easily defined from a common acronym dictionary. Please note that while the acronyms
are in solid caps, terms in the definition should be initial capped ONLY IF they are trademarked names or
proper nouns.
BLDC Brushless DC Motor
PI Proportional-Integral
PWM Pulse Width Modulation
References
The following sources were used to produce this book:
1. 56F8000 Peripheral Reference Manual, MC56F8000RM, Freescale Semiconductor, Inc.
2. 56F8013 Demonstration Board User Guide, MC56F8013DBUG, Freescale Semiconductor, Inc.
3. 56F8000 Motor Control Board User Guide, 56F8000MCBUG, Freescale Semiconductor, Inc.
4. DSP56800E Reference Manual, DSP56F800ERM, Freescale Semiconductor, Inc.
5. 56F8013 Technical Data, MC56F8013, Freescale Semiconductor, Inc.
6. 3-Phase BLDC Motor Control with Hall Sensors using 56800/E Digital Signal Controllers,
AN1916, Freescale Semiconductor, Inc.
7. 56800/E Accelerated Development System Resource Pak CD-ROM, CD342, Freescale
Semiconductor, Inc. (available from the Literature Distribution Center)

3-Phase BLDC Motor Control, Rev. 1
viii Freescale Semiconductor
Preliminary

Introduction, Rev. 1
Freescale Semiconductor 1-1
Preliminary
Chapter 1
Introduction
1.1 Application Benefits
This document describes the design of a 3-phase BLDC (Brushless DC) motor control applciation
with Hall Sensors, and explains how it is targeted for Freescale’s 56F8013 dedicated motor
control device. The software design takes advantage of the Processor ExpertTM (PE) tool,
included with CodeWarrior.
The theoretical concepts of this application are explained in an application note 3-Phase BLDC
Motor Control with Hall Sensors using 56800/E Digital Signal Controllers, found on the
Freescale Semiconductor web site:
www.freescale.com

Introduction
3-Phase BLDC Motor Control, Rev. 1
1-2 Freescale Semiconductor
Preliminary

System Description, Rev. 1
Freescale Semiconductor 2-1
Preliminary
Chapter 2
System Description
The system is designed to drive a 3-phase BLDC motor. The application meets the following performance
specifications:
• Speed/Voltage control of BLDC motor using Hall sensors
• Torque/Current control
• Start from any motor position without rotor alignment
• DCBus undervoltage fault protection
• Real-time application monitoring via the PC master software application
The BLDC drive introduced in this manual is designed to power a low-voltage BLDC motor equipped
with Hall sensors, which is supplied with the Motor Control Daughter Card. The motor has the following
specifications:
Table 2-1. Motor Information
M1
Characteristic Typical Value Units
Power Rating 6 W
Nominal Voltage 9.0 Volt
No-Load Speed 8600 rpm
Stall Torque 20 mNm
Speed / Torque Gradient 479.0 rpm / mNm
No-Load Current 110 mA
Terminal Resistance
Phase-to-Phase
4.50 Ohm
Maximum Permissable Speed 12000 rpm
Maximum Continuous Current at 5000rpm 1.03 A
Maximum Continuous Torque at 5000rpm 8.70 mNm
Maximum Efficiency 60.0 %
Torque Constant 9.5 mNm / A
Speed Constant 1007 rpm / v

System Description
3-Phase BLDC Motor Control, Rev. 1
2-2 Freescale Semiconductor
Preliminary
2.1 Application Description
A standard system concept is chosen for the drive; see Figure 2-2. The system incorporates the following
hardware:
• 9V DC Power Supply
• 56F8000 Motor Control Daughter Card (Part #APMOTOR56F8000)
• Demostration board for MC56F8013 (Part #DEMO56F8013 or DEMO56F8013-E)
The 56F8013 runs the main control algorithm and generates 3-phase PWM output signals for a 3-phase
inverter according to the user interface and feedback signals.
Mechanical Time Constant 70.0 ms
Rotor Inertia 13.9 gcm2
Terminal Inductance
Phase-to-Phase
1.070 mH
Thermal Resistance Housing
Ambient
6.8 K / W
Thermal Resistance
Winding-Housing
7.4 K / W
Thermal Time Constant
Windings
3.7 s
Thermal Time Constant
Stator
16.1 s
Table 2-1. Motor Information (Continued)
M1
Characteristic Typical Value Units

9V DC
APMOTOR56F8000
Motor Control
Daughter Card
BLDC
motor
Hall Sensors
PWM1-6
P
W
M
Speed
Control
56F8013
G
P
I
O
S
C
I
PC Remote
Monitoring
DEMO56F8013
Commutation
Handler
Ω
Req
PI (Speed)
Controller
T
I
M
E
R
Speed
Calculation
Ω
Act
Duty Cycle
A
D
C
PI (Torque)
Controller
Under-Voltage
Fault Detection
Fault
LED
DC Bus Voltage
DC Bus Current
9V DC
APMOTOR56F8000
Motor Control
Daughter Card
BLDC
motor
Hall Sensors
PWM1-6
P
W
M
Speed
Control
56F8013
G
P
I
O
S
C
I
PC Remote
Monitoring
DEMO56F8013
Commutation
Handler
Ω
Req
PI (Speed)
Controller
T
I
M
E
R
Speed
Calculation
Ω
Act
Duty Cycle
A
D
C
PI (Torque)
Controller
Under-Voltage
Fault Detection
Fault
LED
DC Bus Voltage
DC Bus Current
Application Description
System Description, Rev. 1
Freescale Semiconductor 2-3
Preliminary
Figure 2-2. System Concept
The control process is as follows:
The state of the user interface is periodically scanned, while the speed of the motor is measured with each
new edge from the Hall sensors; only one phase is used for speed measurement. The speed command is
calculated according to the state of the control signals. The comparison between the actual speed
command and the measured speed generates a speed error, which is input to the PI Speed controller that
acts as an input to the PI Torque controller. Together with measured current, it forces the PI Torque
controller to generate a new corrected duty cycle. The duty cycle value, together with the commutation
algorithm, creates the PWM output signals for the BLDC power stage.
The Hall sensor signals are scanned independently of speed and torque controls. Each new coming edge
of any Hall sensor signal calls the interrupt routine, which executes the commutation algorithm.
If undervoltage occurs, the PWM outputs are disabled and the fault state is displayed.

System Description
3-Phase BLDC Motor Control, Rev. 1
2-4 Freescale Semiconductor
Preliminary
2.2 Hardware Design
This application utilizes the following HW modules:
• 56F8000 Motor Control Daughter Card (Part #APMOTOR56F8000)
• Demostration board for 56F8013 (Part #DEMO56F8013 or DEMO56F8013-E)
Refer to corresponding User Manual for more information on these boards.
2.3 Software Design
This section descibes the design of software blocks.

Software Design
System Description, Rev. 1
Freescale Semiconductor 2-5
Preliminary
2.3.1 Data Flow
The control algorithm of a closed-loop BLDC drive is described in Figure 2-3. The individual processes are
described in the following sections.
Capture Interrupt
SensorState
Hall
Sensors
Calculate Actual
Speed
MeasuredVoltageFraction
Speed
Setting
via
Button
Calculate Desired
Speed
DesiredVoltageFraction
PI Speed Controller
PI Speed Controller
DCBus
Current
ADC Conversion
Interrupt
Calculate Moving
Average
ADCAvg
PI Torque
Controller
Mask and Swap
Calculation
DCBus
Voltage
ADC Conversion
Interrupt
Calculate Moving
Average
DCBusAvg
PWM
Generation
Yes
DutyCycle
Calculate Duty
Cycle
Overvoltage
Fault?
Shutdown PWM
Figure 2-3. Main Data Flow
The main data flow can be divided into five parts:
• Speed control
• Torque control
• Velocity calculation
• Rotor commutation
• DCBus voltage measurement

System Description
3-Phase BLDC Motor Control, Rev. 1
2-6 Freescale Semiconductor
Preliminary
Speed control starts with the DesiredVoltageFraction variable, which is set by the user button. This
variable is used as one of the inputs to a Speed PI controller. The second input to the Speed PI controller
is the MeasuredVoltageFraction variable, which is derived from the Velocity Calculation algorithm.
Velocity calculation is done by counting CPU clocks between the edges on one of the Hall Sensor phases
(phase A). With a 4-pole motor, there are eight speed captures per one mechanical revolution, as shown in
Figure 2-4:
123456123456123456123456
1 Electrical Rev. 1 Electrical Rev. 1 Electrical Rev. 1 Electrical Rev.
1 Mechanical Revolution
Hall Sensor
Phase A
Hall Sensor
Phase B
Hall Sensor
Phase C
Speed
Capture
Commutation
12345678
Figure 2-4. Speed Capture
At a maximum speed of 8600rpm, each timer capture should have a count of 218, calculated as follows:
9V = 8600rpm or 143.3 revolutions per second
By performing eight speed captures per revolution, there are 1146.6 captures per second, which translates
to 872µsec per capture.
Since the capture timer is running at 250KHz or 32MHz / 128, a maximum rate of 8600 rpm will translate
to 218 timer ticks for each capture.
To find the actual voltage fraction, divide 218 by the measured timer ticks. For example, if 218 timer
ticks are measured, the voltage fraction is 1, or 100% (9V). If 436 timer ticks are measured, the voltage
fraction is 0.5, or 50% (4.5V)

Software Design
System Description, Rev. 1
Freescale Semiconductor 2-7
Preliminary
The output from the Speed PI controller is used as one of the inputs to a Torque PI controller. The second
input to the Torque PI controller is the ADCAvg variable, which is derived from the DCBus current’s
moving average algorithm. The Torque PI controller’s output determines the duty cycle of the generated
PWM output signals.
The rotor commutation process performs mask and swap calculations’ control. The proper PWM output
can be generated by changing the PWM value (duty cycle) registers only. This has two disadvantages:
The first is that the speed controller, which changes the duty cycle, affects the commutation algorithm
(performed by changing the duty cycle). The second disadvantage is that a change in the duty cycle is
synchronized with PWM reload, which may cause a delay between a proper commutation moment and
the PWM reload. This is especially pronounced at high speed when the commutation period is very short.
The 56F801x device has two features dedicated to BLDC motor control: the ability to swap odd and even
PWM generator outputs and the ability to mask (disable) any PWM generator outputs. These two features
allow creation of a rotational field without changing the contents of the PWM value registers. The
commutation algorithms calculate PWM mask and swap values based on the SensorState variable and the
ClockWiseCommTable look-up table. The mask and swap values are written into the PWM Channel
Control Register.
The DCBus voltage measurement acts as a fault detection, which disables PWM if voltage drops below
7V.

System Description
3-Phase BLDC Motor Control, Rev. 1
2-8 Freescale Semiconductor
Preliminary