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List of figures – Motorola M68HC08 User Manual

Page 9

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DRM028 — Rev 0

Designer Reference Manual

MOTOROLA

9

Designer Reference Manual — Sensorless BLDC Motor Control

List of Figures

Figure

Title

Page

2-1

System Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3-1

BLDC Motor Cross Section. . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3-2

3-Phase Voltage System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

3-3

BLDC Motor Back EMF and Magnetic Flux . . . . . . . . . . . . . . . 26

3-4

Classical System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

3-5

Power Stage — Motor Topology. . . . . . . . . . . . . . . . . . . . . . . . 28

3-6

Phase Voltage Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

3-7

Mutual Inductance Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

3-8

Detail of Mutual Inductance Effect . . . . . . . . . . . . . . . . . . . . . . 33

3-9

Mutual Capacitance Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

3-10

Distributed Back-EMF by Unbalanced
Capacity Coupling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

3-11

Balanced Capacity Coupling. . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3-12

Back-EMF Sensing Circuit Diagram . . . . . . . . . . . . . . . . . . . . . 37

3-13

The Zero Crossing Detection . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3-14

Commutation Control Stages . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3-15

Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

3-16

BLDC Commutation with Back-EMF
Zero Crossing Sensing Flowchart. . . . . . . . . . . . . . . . . . . . . . . 42

3-17

BLDC Commutation Time with Zero Crossing Sensing . . . . . . 43

3-18

Vectors of Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

3-19

Back-EMF at Start Up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

3-20

Calculation of the Commutation Times During the Starting
(Back-EMF Acquisition) State. . . . . . . . . . . . . . . . . . . . . . . . . . 49

4-1

High-Voltage Hardware System Configuration . . . . . . . . . . . . . 59

4-2

Low-Voltage Evaluation Motor Hardware
System Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

4-3

Low-Voltage Hardware System Configuration . . . . . . . . . . . . . 63

4-4

MC68HC908MR32 Control Board . . . . . . . . . . . . . . . . . . . . . . 65

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