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System concept, The application block diagram is shown in, Figure 2-1 – Motorola M68HC08 User Manual

Page 16: The sensorless, System description, Freescale semiconductor, inc

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System Description

Designer Reference Manual

DRM028 — Rev 0

16

System Description

MOTOROLA

Figure 2-1System Concept

During the rotor alignment state, the dc-bus current is controlled by the
current PI regulator. In the other states (motor running), the phase
voltage (PWM duty cycle) is controlled by the speed PI regulator.

ADC

Speed PI

Regulator

HC08MR32

Power line

Actual Speed

PWM

BEMF Zero
Crossing
signal

Three-Phase

Inverter

3-ph

BLDC

Motor

START

STOP

SPEED

PWM

Generator

with

Dead Time

PC Master

SCI

3 phase BLDC

Power Stage

Commutation
Control

Zero Crossing
Period, Position
Recognition

Zero
Crossing

Duty
Cycle

Required
Speed

1/T

Commutation
Period

Zero Crossing
Time moment

3 BEMF Voltage

Zero Crossing

Comparators

Digital
Inputs

DC-Bus Voltage/
Current
Temperature

MUX

MUX
Command

Digital
Outputs

DC Bus Current &

DC Bus Voltage

Sensing

Current PI
Regulator
(for Alignment)

Required
Alignment
Current

Actual
Current

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Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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