3-Phase BLDC Motor Control with Hall Sensorread.pudn.com/downloads362/ebook/1574390/3-Phase...

3-Phase BLDC Motor Control with Hall Sensor

V1.3 - Dec 22, 2006 English Version

19, Innovation First Road • Science Park • Hsin-Chu • Taiwan 300 • R.O.C.

Tel: 886-3-578-6005 Fax: 886-3-578-4418 E-mail: [email protected]

http://www.sunplusmcu.com http://mcu.sunplus.com


© Sunplus Technology Co., Ltd. PAGE 1 V1.3 - Dec 22, 2006

Important Notice

SUNPLUS TECHNOLOGY CO. reserves the right to change this documentation without prior notice. Information

provided by SUNPLUS TECHNOLOGY CO. is believed to be accurate and reliable. However, SUNPLUS

TECHNOLOGY CO. makes no warranty for any errors which may appear in this document. Contact SUNPLUS

TECHNOLOGY CO. to obtain the latest version of device specifications before placing your order. No

responsibility is assumed by SUNPLUS TECHNOLOGY CO. for any infringement of patent or other rights of third

parties which may result from its use. In addition, SUNPLUS products are not authorized for use as critical

components in life support systems or aviation systems, where a malfunction or failure of the product may

reasonably be expected to result in significant injury to the user, without the express written approval of Sunplus.



Revision History

Revision Date By Remark Page Number(s)

V1.3 2006/12/22 Li Jing Proofreading

V1.2 2006/05/25 Li Jing Translate ‘3-Phase BLDC Motor Control with Hall Sensor V1.2, Chinese version’



Table of Content PAGE

1 Operation Principle ............................................................................................................................ 4

1.1 Summary of BLDC......................................................................................................................... 4 1.2 Basic Principle ............................................................................................................................... 4 1.3 Driving for BLDC............................................................................................................................ 5 1.4 Speed Regulation by PWM Control............................................................................................... 6

2 Hardware Design ................................................................................................................................ 8

2.1 SPMC75F2413A Application Circuit ............................................................................................ 10 2.2 IPM Module and Driver................................................................................................................ 10 2.3 Position Detecting........................................................................................................................ 13

3 PID Controller ................................................................................................................................... 14

4 Software Design................................................................................................................................ 17

4.1 Software Description ................................................................................................................... 17 4.2 Source File .................................................................................................................................. 17 4.3 DMC Interface ............................................................................................................................. 17 4.4 Subroutines ................................................................................................................................. 17

5 Demo Listing..................................................................................................................................... 20

5.1 Demo ........................................................................................................................................... 20 5.2 Main Process Description............................................................................................................ 21 5.3 ISR Description............................................................................................................................ 22

6 MCU Resource .................................................................................................................................. 23

7 Test..................................................................................................................................................... 24

7.1 Control Signals ............................................................................................................................ 24 7.2 Speed Adjustment........................................................................................................................ 26 7.3 Current Waveform ....................................................................................................................... 27 7.4 System Response ....................................................................................................................... 28

8 Reference .......................................................................................................................................... 32



1 Operation Principle

1.1 Summary of BLDC

Since current BLDC has substituted the electrical commutator for the mechanical one, it conquered the disadvantages of noise, spark, electromagnetic disturbance, short lifetime, etc. Now BLDC is provided with advantages of simple structure, dependable operation and easy maintenance as AC motor does, as well as advantages of high efficiency, no excitation cost and functional speed regulation as traditional DC motor does. Thus, it is widely used in various fields of industrial control presently.

1.2 Basic Principle

Usually, motor stator winding is three-phase symmetry star connection type which is similar to three-phase asynchronous motor. Since motor rotor is assembled with magnetized permanent magnet, in order to detect rotor polarity, a position sensor is built in motor. Motor driver, consisting of inverters and integrated circuit, is designed for: receiving start/stop/brake signals to control the motor operations; capturing position and forward/backward rotate signals to control the transistors state and make BLDC generate the continuous torque; receiving speed command and speed feedback signal to control and adjust rotate speed; protecting BLDC. The basic principle of BLDC is shown as Figure 1-1.

Figure 1-1 BLDC Control Principle

The main circuit is a typical voltage source AC-DC-AC converter. The inverters supplies a symmetrical rectangular voltage with a permanent amplitude & frequency (5 ~24 KHz). Alternating the N-S pole of permanent magnet makes the position sensor generate H1, H2 and H3 waveform with 120° phase-different, which forms six condition codes: 010, 011, 001, 101, 100, and 110. Via some logic components, these codes control to conduct V6 – V1, V5 – V6, V4 – V5, V3 – V4, V2 – V3, V1 – V2 respectively, that is, load bus of U - >V, W - >V, W - >U, V - >U, V - >W, U - >W with DC voltage in turns. Therefore, each time the rotor revolves a pole-pair, the transistors V1, V2, V3, V4, V5 and V6 are conducted one



by one according to their condition code and the magnetic field produced by stator winding rotates 60 electrical degree for that only two phases winding are loaded. Consequently, the rotor rotates 60 electrical degrees. The new position signal of rotor will be captured via the sensor to form a new set of condition codes, thus to drive the corresponding transistors, which makes the rotor rotate 60 electrical degrees further. Circulating unceasingly, BLDC will generate a continuous torque to rotate the load continuously.

1.3 Driving for BLDC

This application is designed for driving the IGBT built in IPM (Intelligent Power Module) using 120-degree waveform, thus to drive BLDC. The signals of driving IGBT are generated according to the motor position. The feedback position signal is encoded as six condition codes: 010, 011, 001, 101, 100, and 110, which can determine the assignment of IGBT driving signal. Here we add PWM signal to the upper phase and active voltage to the lower one so that we can vary the output voltage by changing the PWM duty. The timing of driving assignment and position signals are shown as Figure 1-2.

Figure 1-2 Driving and Position Signals

Where, the upper phase transistors V1, V3, V5 and the lower phase transistors V2, V4, V6 consist of a three-phase full-bridge circuit which controls the current direction of U, V, W phases which are connected as shown in Figure 1-1. H1, H2 and H3 are hall signals.



If the motor is driven in forward direction as shown in Figure 1-2, the transistors are conducted as the sequence: 010 (H3 H2 H1) V6-V1, 011 (H3 H2 H1) V5-V6, 001 (H3 H2 H1) V4-V5, 101 (H3 H2 H1) V3-V4, 100 (H3 H2 H1) V2-V3, 110 (H3 H2 H1) V1-V2. Accordingly, based on the position signal, the conducting sequence of transistors when the motor rotates in backward direction can be obtained as: 001 (H3 H2 H1) V1-V2, 011 (H3 H2 H1) V2-V3, 010 (H3 H2 H1) V3-V4, 110 (H3 H2 H1) V4-V5, 100 (H3 H2 H1) V5-V6, and 101 (H3 H2 H1) V6-V1. The commutate timing should be considered carefully; otherwise, BLDC will vibrate or doesn’t work, or will have a larger current with a wrong waveform.

The control signals mentioned above control the state of transistors, thus make the current flow into the three-phase coil (U, V, W) in turn and accordingly generate rotating magnetic field within BLDC. Figure 1-3 shows the current timing of each phase.

Figure 1-3 Current Timing

1.4 Speed Regulation by PWM Control

The inverters are based on the PWM modulation, which means that they can vary the output voltage fundamental with different PWM duty, thus to control the motor speed. There are totally 4 methods to add PWM-based control: upper phase, lower phase, pre-sixty degree and post-sixty degree as shown in Figure 1-4.



(a) Upper Phase PWM

(b) Lower Phase PWM

(c) Pre-sixty Degree PWM

(d) Post-sixty Degree PWM

Figure 1-4 Commutate Timing When Active High



2 Hardware Design

BLDC is widely applied in various technology fields with different control methods. This application adopts SPMC75F2413A chip equipped with a 16-bit TPM (Timer PWM Mode, TPM) timer and IPM (Intelligent Power Module) via basic driving algorithm to drive and adjust rotate speed of three-phase winding BLDC

The hardware circuit mainly contains power supply, control system, IPM and the corresponding driver, position sensors and RS232 communication module. The hardware block diagram and schematic are shown in Figure 2-1 and Figure 2-2 respectively.

Figure 2-1 System Block Diagram

In the following, we will illustrate IPM and the corresponding driver, position sensors and RS232 communication module in detail.



WP

UART-TXD

MO

TO

R1-

WN

STEP-B

D22

LED

12

IC15

74HC373

111

20

256912151619

3478

13141718

OELE

VCC

1Q2Q3Q4Q5Q6Q7Q8Q

1D2D3D4D5D6D7D8D

STEP-A

MO

SI

IC16PC817

12

43

R57

5.1K

R53

1.8K

XTAL2

P+15V

ProbeSDA

C400.22uF

CON8

Probe conn

12345

Q22N3904

2

13

Drive

S1

C46100pF

P+15V

+5V

S2

UART-TXD

DRV-EN

MOTOR1-WP

UART-RXD

P+15V

HC

UR

MO

TO

R1-

VN

TSE

N1

R401K

IC8

PS21563

123456

789101112

131415161718

192021222324252627282930

31

32

33

34

35

VUFSNC

VUFBVP1NCUP

VVFSNC

VVFBVP1NCVP

VWFSNC

VWFBVP1NCWP

NCVNO

UNVN

WNFO

CFOCIN

VNCVN1NCNC

P

U

V

W

N

VVFB

IOD

7

Prob

eSD

A

Protect

CIN

VVFS

ProbeEN

MO

TO

R1-

UP

LED

3

UART-RXD

SEG

1

+5V

+5VA

VVFS

R553.9K

MOTOR1-VN

FAN-UN

IOD

4

R58

10

TSE

N1

SOFT-RELAY

R261K

AVSS

FOIN1

Q42N3904

2

13

R131

2.2K

C300.22uF

D10MUR160

12

P+5V

DRV-EN

HALL-U2

DRV-EN

WN

FO

+5

UN

FAN-UP

MO

TO

R1-

VP

RE

SET

V

ACZVC

HC

UR

UP

C550.1uF

IC29

MAX232

1

2

5

3

4

1110

129

16

6

15

147

138

C1+

Vs+

C2-

C1-

C2+

T1INT2IN

R1OUTR2OUT

VCC

Vs-

GND

T1OUTT2OUT

R1INR2IN

IPM-MW

MIS

O

MO

TO

R1-

WP

SCFO

Q52N3904

2

13

+C51LXZ-33uF/35V

+C48LXZ-33uF/35V

MOTOR1-WN

D8MUR160

12

R123

2.2K

IC11PC817

12

43

R1IN

SOFT-RELAY

C45100pF

MOTOR1-VN

VVFB

HA

LL-U

1

+C43LXZ-33uF/35V

R563.9K

Q72N3904

2

13

R353.9K

IPM-MU

VN

C500.22uF/50V

R421K

+5V

IOD

6

INFRAD

ACI-CLKB

+5V

IPM-MV

OLIN2

FAN-VP

IC14PC817

12

43

RESET

MHALL-U

C990.1uF

FAN-VN

P+15V

R4910K

C930.1uF

IC10PC817

12

43

C790.1uF

+5V

+5VA

IPM-MW

VUFS

T1OUT

SEG

4

S1SW

P+5V

MHALL-W

VWFS

R523.9K

FAN-UP

TSE

N5

UP

+5V

MOTOR1-VP

ACI-CLKC

STEP-BN

SEG

3

MO

TOR

1-U

P

VD

DL

R3310K

IC4C

74HC00_0

9

108

+5V

IPM-MV

HALL-V2

DIR-VALVE

VDDL

MO

TO

R1-

UN

Prob

eEN

P+15V

TSE

N4

VBU

S

S1

R129

3.3K

C491000pF

+5V

TSE

N2

VWFS

R513.9K

R591K

IC4D

74HC00_0

12

1311

MO

TOR

1-V

N

CON6

HALL SENSOR

12345

R271K

R373.9K

+5V

SCFO

R1IN

R61

10

VBU

S

+ C97220uF/16V

P+15V

S5

C96

20pF

1 2

+5V

FOIN1

R3210K

S6

Y16M

LED

4

FAN-WN

STEP-AN

D201N4148

12

C44100pF

N

STU-LED

TSE

N2

R4810K

R17510K

VP

HA

LL-V

1

D9MUR160

12

C390.22uF

VCC

AVSS

MOTOR1-VP

S4

UN

MOTOR1-UN

C520.22uF/50V

AVC

MD

+5V

C34100pF

FO

R45330

+C53LXZ-33uF/35V

C1050.1uF

12

R30330

+5V

CON3TO-MOTOR

123

P+5V

STU-LED

HALL-V2

MPC

LK

HALL-U2

FAN-UN

IOD

5

+5V

P+5V

MOTOR1-UN

XTAL1

R343.9K

Q62N3904

2

13

MO

TOR

1-V

P

VUFB

S3

R150220

+ C98220uF/16V

P+5V

MOTOR1-WP

FAN-VN

VDC

C540.22uF/50V

+5V

S3

C1040.1uF

12

C32100pF

FAN-WN

AVC

MD

MOTOR1-WN

MO

TOR

1-W

N

HA

LL-W

1

R29330

C1000.1uF

D213.3V

12

1206

FB260_ohm_3A_1206

HALL-W2

HAL

L-V

1

Prob

eSC

L

R251K

S2

C940.1uF

12

R3110K

P+5V

VUFB

HAL

L-W

1

CIN

N

EMGSTOP

R117

3.3K

+5V

FOIN

1

FOIN2

XTA

L1

R543.9K

IC13PC817

12

43

C1010.1uF

R393.9K

C850.1uF

SPMC75F2413A

S6

ProbeSCL

C310.22uF/50V

R363.9K

P+15V

P+5V

VWFB

S4

R601K

R62

10

C33100pF

C280.22uF

TSE

N4

MPSTE

FAN-WP

ACZVC

SEG

2

MHALL-V

VWFB

C350.22uF/50V

R411K

R122

3.3K

R503.9K

T1OUT

ACI-CLKD

TSE

N5

R4710K

Q172N3904

21

3

R14010K

UART

VP

MOTOR1-UP

C95

20pF

1 2

R383.9K

C380.22uF

R46BRP58F0.082-K

C410.022uF/50V

WP

LED

2

ACI-CLKA

1206

FB160_ohm_3A_1206

C473300pF

IC12PC817

12

43

IPM-MU

WN

OLI

N1

FOIN2

BUZZER

C290.22uF

R148100

MO

TOR

1-U

N

XTA

L2

LED

1

R149200K

C360.22uF/630VDC

HALL

+5V

FAN-VP

FO

IN1

VN

IC9PC817

12

43

Q182N3904

2

13

R43330

R118

2.2K

MOTOR1-UP

VUFS

HALL-W2

IC4B

74HC00_0

4

56

Q192N3904

2

13

HAL

L-U

1C42

0.22uF/50V

+C9210uF/16V

VDC

FAN-WP

S5

TSE

N3

DRV-EN

R44330

C370.22uF/50V

C820.1uF

P4

CONNECTOR DB9

594837261

TSE

N3

MO

TOR

1-W

P

R28330

P+5V

U1

SPMC75F2413A - QFP80

55 5354

1

52

2 3 4 5 76 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

25262728293031323334353637

60 59 58 57 568

5051 49 48 47 46 45 44 43 42 41

403938

80797877767574737271706968676665

64 63 62 61

VSSL

XTA

L1X

TAL2

TEST

VDD

L

ICE

CLK

ICE

SDA

IOD

0/IC

EC

LKIO

D1/

ICE

SDA

RE

SET

IOD

2

NC

NC

IOB

0/TI

O3F

/W1N

IOB

1/TI

O3E

/V1N

IOB

2/TI

O3D

/U1N

IOB

3/TI

O3C

/W1

IOB

4/TI

O3B

/V1

IOB

5/TI

O3A

/U1

IOB

6/FT

IN1

IOB

7/O

L1IO

B8/

TIO

0CIO

B9/

TIO

0BIO

B10

/TIO

0AIO

B11

/SC

KIO

B12

/SD

I/RX

D1

IOB

13/S

DO

/TX

D1

IOB14IOB15IOD12IOD13IOD14IOD15

IOA8IOA9/TIO2A

IOA10/TIO2BIOA11/TCLKAIOA12/TCLKBIOA13/TCLKCIOA14/TCLKD

IOD

8IO

D7

IOD

6IO

D5

IOD

4IO

D3

AVSS

AVD

D

VEX

TREF

IOA

7/A

N7

IOA

6/A

N6

IOA

5/A

N5

IOA

4/A

N4

IOA

3/A

N3

IOA

2/A

N2

IOA

1/A

N1

IOA

0/A

N0

VSSVDD

IOA15/ADCTRG

IOC15/TIO4F/W2NIOC14/TIO4E/V2NIOC13/TIO4D/U2NIOC12/TIO4C/W2IOC11/TIO4B/V2IOC10/TIO4A/U2IOC9/FTIN2IOC8/OL2IOC7/TIO1CIOC6/TIO1BIOC5/TIO1AIOC4/BZOIOC3/EXINT1IOC2/EXINT0IOC1/TXD2IOC0/RXD2

NC

IOD

11IO

D10

IOD

9

+5V

IPM

C1020.1uF

12

C1030.1uF

12

IC4A

74HC00_0

1

23

Q32N3904

2

13

R17210K

IC34PC817

12

43

C1190.1uF

C1180.1uF

IC35TOP234P1 5

2 3 7 8

4

M D

S S S S

C

L1Choke

C122KX-2200pF/250VAC

CT1

+12V

T2

TR-10

1

3

4

5 6

79

10

C20X1-0.22uF/250VAC

D28P6KE200A

12

P1

N

R168470

P+5V

+ C114470uF/25V

+C23JACK-470uF/400V

D27

MUR160

1 2

EARTH

ACZVC

D30MUR160

12

D51N4148

12

P+18V

SOUT

P+18V

C19X1-0.22uF/250VAC

R191K

+5V

R170680

IC337815

1

2

3VI

GN

D

VO

VDC

R20200K,1/2W

T1CT

Q12N3904

2

1 3

C1200.1uFVDC

L3100uH

R2110K

R1660

R17451, 1W

ZNR315G471K

IC7PC817

12

43

D32

1N4148

12

CON11

VAC input

123

VCC

CT2

D311N5822

1 2

EMI

+5V

C1160.1uF

C18Y2-2200pF/250VAC

IC36TL431

23

1ROUT

SOUT

Switching Power Supply

R22470

SOFT-RELAY

+

C12133uF/35V

VDC

R167910K

R17310

+5VC25Y2-2200pF/250VAC

ROUT

SOFT-RELAYVDC

+C11747uF

R2320K

P+15V

ZNR115G471K

ZNR215G471K

C1130.1uF

R24200K

C21KH-103K/250VAC

C24224K/630VDC

D6

1N4148

1 2

C22Y2-2200pF/250VAC

+12V

P+15V

L23.3uH

R16939.2K

- +

DB1GBU6K

1

3

2

4

C270.1uF

+ C112470uF/35V

tRT1

PTC

C26100pF

SOUT

ROUT

+C110470uF/25V

+C12447uF

R1651M

C1230.1uF

IC3778L05

1

2

3VI

GN

D

VO

ZNR415G471K

D29

MUR160

1 2

D7

1N4148

12

+ C115470uF/25V

F1

10A

R1713.3K

L43.3uH

+5V/P+15V/P+5V power

RLY1

G6B-1174P-US

34

16

ACZVC

+C111470uF/25V

IC32SI-8050S

1

5

2

4

3

VIN

SS

SWOUT

VOSGN

D

C1250.1uF

L5100uH

Figure 2-2 Hardware Schematic



2.1 SPMC75F2413A Application Circuit

The SPMC75F2413A is the embedded 16-bit micro-controller, designed for inverter-fed motor driver, power electronics, home appliance and car fan control system, etc.

Figure 2-3 shows the hardware schematic of SPMC75F2413A.

Figure 2-3 SPMC75F2413A Hardware Block Diagram

Connecting the embedded In-Circuit-Emulation circuit of SPMC75F2413A via Probe can facilitate the development for user, accordingly improve the production efficiency and reduce time to market.

2.2 IPM Module and Driver

IPM (Intelligent Power Module) product is designed and developed with the advantages of reduced design, development and manufacturing costs as well as increased system reliability through self protection circuits (such as over-current, over-voltage, and over-temperature circuits) . It also supplies a solution for users to drive low-power BLDC. Figure 2-4 shows IPM electrical connections.



P+15V

C410.022uF/50V

IPM-MV

CIN

IPM-MW

R53

1.8K

IPM-MU

+C43LXZ-33uF/35V

VWFB

VUFB

N

P+15V

UN

P+15V

CON3TO-MOTOR

123

C370.22uF/50V

C310.22uF/50V

IPM-MU

VN

C360.22uF/630VDC

CIN

VUFS

VVFS

IC8

PS21563

123456

789101112

131415161718

192021222324252627282930

31

32

33

34

35

VUFSNC

VUFBVP1NCUP

VVFSNC

VVFBVP1NCVP

VWFSNC

VWFBVP1NCWP

NCVNO

UNVN

WNFO

CFOCIN

VNCVN1NCNC

P

U

V

W

N

VWFS

C473300pF

R17510K

C420.22uF/50V

IPM-MW

P+15V

N

P+5V

R46BRP58F0.082-K

WN

VP

FO

VVFB

VDC

WP

IPM-MVC350.22uF/50V

VDC

UP

Figure 2-4 IPM Electrical Connections

To protect MCU, electrical isolation is done between IPM and MCU with HVDC (High Voltage Direct Current) which improves the stability and reliability of system. Figure 2-5 shows the electrical diagrams via optical isolating the drive between IPM and MCU.

Where:

IC8: IPM PS21563

C31, C35, C37: bootstrap capacitor 0.22uF/50V

C41: malfunction pulse width timing capacitor (ceramic material) 0.022uF/50V

C42: decoupling capacitor 0.22uF/50V

C43: power supply filter capacitor 33uF/35V

C47: short-circuit sampling RC filter capacitor 3300pF

R46: short-circuit current limiting resistance 0.082Ω



S2

R4810K

Q32N3904

2

13 R33

10KS1

R43330

C33100pF

IC10PC817

12

43

IC14PC817

12

43

P+5V

S5

Q62N3904

21

3

R421K

P+5V

R4710K

R411K

R30330

R383.9K

R363.9K

P+5V

S4

R4910K

Q22N3904

2

13

R523.9K

IC13PC817

12

43

+5V

IC9PC817

12

43

+5V

+5V

P+5V

C32100pF

R3110K

R44330

WPUP

Q42N3904

2

13

IC12PC817

12

43

R261KR29

330

R503.9K

+5V

R45330

WNUN

R543.9K

R3210K

R401K

C45100pF

C300.22uF

C290.22uF

R373.9K

VN

C400.22uF

R343.9K

IC11PC817

12

43

S3

R513.9K

C380.22uF

Q52N3904

2

13

C390.22uF

R28330

R563.9K

P+5V

VP

C34100pF

R553.9K

+5V

Q72N3904

2

13

S6

R353.9K

C280.22uF

R271K

P+5V

R393.9K

+5V

C46100pF

R251K

C44100pF

Figure 2-5 Optical Isolate the Drive Between IPM and MCU

Where, OC (Optical Coupler) must be connected to different power supplies in its two sides to implement electrical isolation. It is recommended to adopt quick OC, however, when the carrier wave frequency is not required too high, PC817/TLP521 OC can also be considered to reduce the cost.

Additionally, the ability of the IPM to self protect in fault situations is critical when MCU runs abnormally. Therefore, a “protect lock” is specially designed into hardware circuit. Once an error is detected, the driving signal sent to IPM will be cut off immediately and the hardware will request for IRQ to MCU at the same time. Upon eliminating the error, MCU enables the signal output bit to run IPM again. Figure 2-6 shows the hardware protection circuit.

IC4A

74HC00_0

1

23

MOTOR1-WP

MOTOR1-VN

IC15

74HC373

111

20

256912151619

3478

13141718

OELE

VCC

1Q2Q3Q4Q5Q6Q7Q8Q

1D2D3D4D5D6D7D8D

MOTOR1-VP

IC4B

74HC00_0

4

56

FO

MOTOR1-UN

IC4C

74HC00_0

9

108

S6MOTOR1-WN

+5V

FOIN1

R601K

MOTOR1-UP

SCFO

SCFO

MOTOR1-UNMOTOR1-WP

S1MOTOR1-VP

S2

C491000pF

IC16PC817

12

43

+5V

MOTOR1-WN

DRV-EN DRV-ENFOIN1

P+5V

R591K

MOTOR1-UP

MOTOR1-VN

S5S4

S3

IC4D

74HC00_0

12

1311

R57

5.1K

Figure 2-6 Hardware Protection Circuit

Where, IC15: 74HC373; IC4: 74HC00.



2.3 Position Detecting

Since commutate timing of BLDC depends on rotor position which determines the next excited phase, it is important to detect the current rotor position for driving BLDC. This application selects the BLDC integrated with Hall sensor as shown in Figure 2-7.

Q182N3904

2

13

C850.1uF

+5V

R131

2.2K

R122

3.3K

C820.1uF

+5V

MHALL-W

+5V

Q192N3904

2

13

MHALL-V

R117

3.3K

Q172N3904

2

13

R118

2.2K

R129

3.3K

+5V

MHALL-U

CON6

HALL SENSOR

12345

C790.1uF

R123

2.2K

Figure 2-7 Hall Sensor



3 PID Controller

The PID controller is commonly used to adjust speed. It receives signals from sensors and computes corrective action to the actuators from a computation based on the error (Proportion), the sum of all previous errors (Integral) and the rate of change of the error (Derivative). The mathematical model of the PID controller can be represented as:

])()(1)([)(u0 dt

tdeTddtteTi

teKptt

++= ∫ (Formula 3-1)

Where:

u(t) Output of PID controller

e(t) Input of PID controller, which is the error between the desired input value and the actual output value, so called error signal.

Kp Proportional gain

Ti Integral time, also called integral gain

Td Derivative time, also called derivative gain

The mathematical model of the PID controller consists of Proportional Response, Integral Response and Derivative Response which are described as follows:

1. Proportional Response

The proportional component can be expressed as Kp*e(t).

In PID controller, the effect of controlling error depends on the proportional gain (Kp). In general, increasing the proportional gain will increase the speed of the control system response and reduce the steady-state error. However, if the proportional gain is too large, the system will begin to oscillate and become unstable. Thus, Kp must be suitably selected to keep the system stable and reduce the rise time and steady-state error.

2. Integral Response

The integral component can be expressed as∫t

dtteTiKp

0)(

.

From the expression shown above, we can see that the integral component sums the error term over time. The result is that even a small error term will cause the integral component to increase slowly. The integral response will continually increase over time unless the error is zero, so the effect is to drive the Steady-State error to zero.

But the integral control will reduce the speed of the overall control system response and increase the overshoot. Increasing the integral gain (Ti) will cause the integral component to accumulate weakly and reduce the overshoot, thus it will make system not oscillate during the rising time, therefore improve its stability. However, it will slow the



process of eliminating Steady-State error. Reducing Ti will strengthen the accumulation of integral component and shorten the time of eliminating error, but it will make the system oscillate. So Ti should be selected according to the practical needs.

3. Derivative Response

The derivative component can be expressed as dttdeTdKp )(*

.

The effect of derivative component depends on the derivative time constant (Td). In general, the larger Td, the better the effect to restrain the change of e(t) and vice versa. Thus, to select Td properly can make the derivative component better meets the system requirement.

The appearance of computer makes it easy to perform PID control by software to realize the control of Formula 3-1 is called digital PID control.

Since software control method uses sampling, which calculates the control signals based on the error at the sampling point, the signal cannot be output serially as analog control method does. Therefore, the integral and derivative components must be discrete.

])1()()()([)(1 T

kekeTdjeTiTkeKpku

k

j

−−++= ∑

=

(Formula 3-2)

Where:

K Sampling number, k=0, 1, 2 …

Uk Output value sampling at the K times

ek Error sampling at the K times

∑=

k

j

je1

)( Accumulative error sampling from the first time to the k times

T Sampling period

In Formula 3-2, make )1()()( −−=∆ kekeke

Thus:

)]()()([)k(u1

keTTdje

TiTkeKp

k

j

∆++= ∑=

(Formula 3-3)

In the above formula, let TiKpKi /= , TdKpKd *=

Thus:

)()(*K)(*)(1

keTKdjeTikeKpku

k

j

∆++= ∑=

(Formula 3-4)



To avoid calculating ∑ (the sum of errors), the recursion formula ( ) of

increment PID algorithm is instead in practice where=

k

j

je1

)( )(u t∆

)1(u)(u)(u −−=∆ kkk .

Since

)1()(*K)1(*)1-k(u1

1

−∆++−= ∑−

=

keTKdjeTikeKp

k

j

(Formula 3-5)

And

)1()()( −−=∆ kekeke

)2()1()1( −−−=−∆ kekeke

Thus:

)]2()1(2)([)(**K)]1()([)k(u −+−−++−−=∆ kekekeTKdkeTikekeKp

(Formula 3-6)

Formula 3-6 can also be transformed as:

)]2()1(2)([)()]1()([)k(u −+−−++−−=∆ kekekeTTdke

TiTkekeKp

(Formula 3-7)

A closed loop control system puts the regulator under pure proportion function, then changes the proportional gain from small to large to make the system oscillate continuously. The current proportional gain is called the critical gain Ku and the time interval between two neighboring peaks is called critical oscillation period Tu.

Based on Z-N tuning method:

TuT 1.0=

TuTi 5.0=

TuTd 125.0=

Thus:

)]2(25.1)1(5.3)(45.2[)k(u −+−−=∆ kekekeKp (Formula 3-8)

Obviously, the constant Kp is easy to be corrected using above formula.



4 Software Design

4.1 Software Description

This application is designed for driving BLDC using 120-degree upper phase PWM waveform via hall sensor and adjusting motor speed by PID controller. Here we use SPMC75F2413A as an example for demonstration purpose.

4.2 Source File

File Name Function Type

Main Initialize parameters for driving BLDC, monitor BLDC running status (which is also performed in interrupt subroutine)

C

ISR Start up, run, protect BLDC and adjust its speed C

Spmc75 _BLDC_V100 Functions for driving BLDC lib

Spmc75_dmc_lib_V100.lib DMC communication program lib

4.3 DMC Interface

Speed1_Cmd: Set the rotate speed of motor

Speed1_Now: Feedback the current rotate speed of motor

User_R0: Current value in P_TMR3_TGRA

User_R1: Error between the desired speed and the actual speed

Motor 1 Start and Motor 1 Stop: Start/Stop the motor

4.4 Subroutines

Spmc75_System_Init ( )

Prototype void Spmc75_System_Init(void)

Description Initializations for I/O, PDC, MCP, CMT, Fault, PID and DMC

Input Arguments None

Output Arguments None

Head File Spmc75_BLDC.h

Library File Spmc75_BLDC_V100

Note Initialize the resources occupied:

PDC: Timer0; MCP, Fault: Timer3; CMT: CMT0; I/O enable: IOB14; DMC communication interface: UART2 (IOC0-RXD/IOC1-TXD)



Example Spmc75_System_Init();

BLDC_Motor_Startup ( )

Prototype void BLDC_Motor_Startup (void)

Description BLDC start-up ISR





Note Call this subroutine when BLDC starts up or runs at quite a lower speed. It is recommended to call it in TCV interrupt of IRQ1

Example BLDC_Motor_Startup();

BLDC_Motor_Normalrun ( )

Prototype void BLDC_Motor_Normalrun (void)

Description BLDC running ISR





Note Call this subroutine in PDC interrupt of IRQ1 to keep BLDC run normally (including position detection, commutation and speed calculation).

Example BLDC_Motor_Normalrun ();

BLDC_Motor_Actiyator ( )

Prototype void BLDC_Motor_Actiyator(void)

Description BLDC speed control including charging IPM, moving filter, PID adjustment and PWM amplitude limiting.





Note This subroutine is critical to adjust BLDC speed. It is recommended to call this subroutine periodically using timer interrupt (512Hz). The calling frequency is determined by the highest speed of motor.

Example BLDC_Motor_Actiyator ();



BLDC_Run_Service ( )

Prototype void BLDC_Run_Service(void)

Description Monitor BLDC running status





Note This subroutine responds for detecting and receiving the start-up/stop command, which can be called in main loop or timer interrupt within 10KHz.

Example BLDC_Run_Service();

IPM_Fault_Protect ( )

Prototype void IPM_Fault_Protect(void)

Description External fault protection





Note This subroutine which must be called by IRQ0, is designed for protecting BLDC. Once an external fault input signal occurs, interrupt will generate when the output pins are set to high-resistance state.

Example IPM_Fault_Protect();



5 Demo Listing

5.1 Demo

/*=============================================*/ // Application Note /*=============================================*/ #include "Spmc75_regs.h" #include "Spmc_typedef.h" #include "unspmacro.h" #include "Spmc75_BLDC.h" main() P_IOA_SPE->W = 0x0000; P_IOB_SPE->W = 0x0000; P_IOC_SPE->W = 0x0000; Spmc75_System_Init(); // Spmc75 system initialization while(1) BLDC_Run_Service(); // Status Monitor NOP(); //================================================================= // Description: IRQ0 interrupt source is XXX,used to XXX // Notes: Error Protection //================================================================= void IRQ0(void) __attribute__ ((ISR)); void IRQ0(void) IPM_Fault_Protect(); //================================================================= // Description: IRQ1 interrupt source is XXX,used to XXX // Notes: BLDC start up and running service //================================================================= void IRQ1(void) __attribute__ ((ISR)); void IRQ1(void) /*=============================================================*/ // Position detection change interrupt /*=============================================================*/ if(P_TMR0_Status->B.PDCIF && P_TMR0_INT->B.PDCIE) BLDC_Motor_Normalrun(); /*=============================================================*/ // Timer Counter Overflow



/*=============================================================*/ if(P_TMR0_Status->B.TCVIF && P_TMR0_INT->B.TCVIE) BLDC_Motor_Startup(); P_TMR0_Status->W = P_TMR0_Status->W; //================================================================= // Description: IRQ6 interrupt source is XXX,used to XXX // Notes: DMC receives ISR //================================================================= void IRQ6(void) __attribute__ ((ISR)); void IRQ6(void) if(P_INT_Status->B.UARTIF) if(P_UART_Status->B.RXIF) MC75_DMC_RcvStream(); if(P_UART_Status->B.TXIF && P_UART_Ctrl->B.TXIE); /*==================================================================== Description: IRQ7 interrupt source is XXX,used to XXX Notes: 512Hz timing interrupt for adjusting speed by PID controller ====================================================================*/ void IRQ7(void) __attribute__ ((ISR)); void IRQ7(void) if(P_INT_Status->B.CMTIF) if(P_CMT_Ctrl->B.CM0IF && P_CMT_Ctrl->B.CM0IE) BLDC_Motor_Actiyator(); P_CMT_Ctrl->W = P_CMT_Ctrl->W;

5.2 Main Process Description

Main program performs the system initializations, and ISR routines respond for the real time motor operations. The ISR include: input/output error interrupt (IRQ0), PDC and TCV interrupt (IRQ1), UART RXD interrupt (IRQ6) and CMT0 timer interrupt. Figure 5-1 flow charts the main loop.



Figure 5-1 BLDC Main Process

5.3 ISR Description

Fault input, output short circuit, PDC, TCV, RXD and CMT0 interrupt routines help to control BLDC starting, working, speed adjusting and fault protection. These interrupt sources have been configured in the system initialization routines. Figure 5-2 shows the interrupt operation process of PDC and TCV for your reference.

Figure 5-2 PDC and TCV Interrupt



6 MCU Resource

CPU Type SPMC75F2413A Package QFP80-1.0

crystal Frequency 6MHz Oscillator

external Input frequency

WATCHDOG Enable Disable

IOB[0-5] MCP3: BLDC control

IOB6 Motor drive external fault input

IOB[8-10] Hall sensor interface for position detection

IOC[0-1] UART RXD2, TXD2

IO

Other IOs Main control /GND

PDC0 Motor position detection

MCP3 Generate waveform by driving BLDC motor Timer

CMT0 System clock

FTIN1(IRQ0) External fault protection

PDC0(IRQ1) Motor start-up and running normal control

MCP3(IRQ3) Motor driving waveform control

UART(IRQ6) DMC controls UART communication

Interrupt

CMT0(IRQ7) BLDC speed adjustment

ROM 6.15K Words



7 Test

This test is aimed to use 120-degree upper phase PWM waveform to drive BLDC with hall sensor and adjust motor speed by PID controller.

Test contents:

Six phase output signals

WN2: IOB0/W1N

VN6: IOB1/V1N

UN4: IOB2/U1N

W5: IOB3/W1

V3: IOB4/V1

U1: IOB5/U1

Three phase hall input signals

H3: IOB8/TIO0C

H2: IOB9/TIO0B

H1: IOB10/TIO0A

7.1 Control Signals

The relationship between control signal and position feedback signal is available through theoretical analysis and practical operation. Figure 7-1 shows the 120-degree upper phase PWM waveform when the motor is driven in forward direction and Figure 7-2 shows that in backward direction.

Figure 7-1 120-degree Upper Phase PWM Waveforms When the Motor Is Driven in Forward Direction



From the waveform, we can see that when the motor is driven in forward direction, the corresponding relationship between position detection and control signals can be obtained as: 010 (H3 H2 H1) V6-V1, 011 (H3 H2 H1) V5-V6, 001 (H3 H2 H1) V4-V5, 101 (H3 H2 H1) V3-V4, 100 (H3 H2 H1) V2-V3, 110 (H3 H2 H1) V1-V2.

Figure 7-2 120-degree Upper Phase PWM Waveform When the Motor Is Driven in Backward Direction

From the waveform, we can see that when the motor is driven in backward direction, the corresponding relationship between position detection and control signals can be obtained as: 001 (H3 H2 H1) V1-V2, 011 (H3 H2 H1) V2-V3, 010 (H3 H2 H1) V3-V4, 110 (H3 H2 H1) V4-V5, 100 (H3 H2 H1) V5-V6, 101 (H3 H2 H1) V6-V1.

The SPMC75F2413A chip is dedicated to drive motor which can generate various driving signals such as pre-sixty degree PWM waveform shown in Figure 7-3. Here we simply demonstrate a possible design idea and give a reference for user’s further application.



Figure 7-3 Pre-sixty Degree PWM Waveform

7.2 Speed Adjustment

As mentioned above, BLDC speed is adjusted by PID controller which can vary the output voltage fundamental with different PWM duty, thus to control the motor speed. Figure 7-4 and Figure 7-6 respectively depict the waveforms when BLDC runs at 1000rpm and 3200rpm.

Figure 7-4 PWM Waveform (1000rpm)

From the waveform, we can see that when BLDC runs at 1000rpm: Hpwm=22us, Lpwm=102us. Thus PWM duty can be calculated as: Dpwm=Hpwm/ (Hpwm+Lpwm)*100%=22us/124us*100%=17.74%.



Figure 7-5 PWM Waveform (3200rpm)

From the waveform, we can see that when BLDC runs at 3200rpm: Hpwm=94us, Lpwm=32us. Thus PWM duty can be calculated as: Dpwm=Hpwm/ (Hpwm+Lpwm)*100%=94us/126us*100%=74.6%.

7.3 Current Waveform

Figure 7-6 is current waveform tested via current probe during BLDC running. The test conditions are: small load, low current, and 6 KHz PWM carrier waveform.

Figure 7-6 Current Waveform



7.4 System Response

As described in Chapter 3, in order to correct system response, the only thing to do is to chang Kp. Following depicts the system response curves when Kp is set as different values.

Figure 7-7 shows the steady-state characteristic test curve at Kp= 0.385. Obviously, the system oscillates when the rotate speed is low (1000rpm) and has a long duration during rising time (1000rpm ~1500rpm).

Figure 7-7 Steady-State Characteristic Test

Figure 7-8 shows the step response curve at Kp= 0.225 when the rotate speed ranges from 0rpm to 2000rpm.



Figure 7-8 Step Response(0rpm ~ 2000rpm)

From above, we can estimate the overshoot using the formula: σ= (Cmax-C∞) / C∞ * 100%, here σ=230rpm/2000rpm * 100% =11.5%.

Figure 7-9 shows the step response curve at Kp= 0.225 when the rotate speed ranges from 2000rpm to 3500rpm.

Figure 7-9 Step Response (2000rpm ~ 3500rpm)



Additionally, steady-state error must be considered into the speed feedback system. Figure 7-10 shows the steady-state error curve when the rotate speed is 1000rpm, where steady-state errorδ=(C (t)-C∞) / C∞ * 100% < ±10/1000 * 100%=1%.

Figure 7-10 Steady-State Error when the Rotate Speed is 1000rpm

Figure 7-11 shows the steady-state error curve when the rotate speed is 3000rpm, where steady-state error δ=(C (t)-C∞) / C∞ * 100% < ±12/3000 * 100%=0.4%.

Figure 7-11 Steady-State Error when the Rotate Speed is 3000rpm

Figure 7-12 shows the step response curve at Kp=0.225 when the rotate speed ranges from 1000rpm to 3000rpm. We can see that the overshoot is always zero and no oscillation occurs. But the error (C (t)-C∞) is always higher than 150rpm irrespective of whether the rotate speed is lower or higher.



Figure 7-12 Step Response (1000rpm ~ 3000rpm)



8 Reference

【1】SUNPLUS. SPMC75F2413A Programming Guide V1.0. Oct 12 2004.

【2】 Zhang Chen. BLDC Fundamentals and Applications (Version 2). China Machine Press.

【3】Yu Yongquan, Zeng Bi. Fuzzy Logic Control Based on MCU. Beijing University of Aeronautics and Astronautics Press.

3-Phase BLDC Motor Control with Hall Sensorread.pudn.com/downloads362/ebook/1574390/3-Phase...

Documents

Transcript of 3-Phase BLDC Motor Control with Hall Sensorread.pudn.com/downloads362/ebook/1574390/3-Phase...