AN2357 Freescale Semiconductor / Motorola, AN2357 Datasheet - Page 14

• Manufacturer Part Number: AN2357
• Description: Sine Voltage Powered 3-Phase Permanent Magnet Motor with Hall Sensor
• Manufacturer: Freescale Semiconductor / Motorola

AN2357/D
Speed Controller
Torque Limitation
14
Sine Voltage Powered 3-Phase Permanent Magnet Motor with Hall Sensor
The scaled PI controller is used for the speed closed loop. The controller is
called every 5 ms. The controller constants were tuned experimentally.
Because the speed update depends on actual motor speed, the speed
controller constants have to be changed according to the measured speed to
achieve the best result. The controller constants are calculated according to
Equation 7
the edge on the Hall sensor signal is detected. The long distance between the
Hall sensor signal edges in the motor speeds could cause speed fluctuations
of the motor.
where:
The basic concept of torque limitation is shown in
limitation is provided by the generated voltage limitation, based on the
measured speed and motor parameters.
Freescale Semiconductor, Inc.
•
•
•
torque limit
omega
Cφ
omega
For More Information On This Product,
CI is integral constant
CP is proportional constant
C1, C2, C3, and C4 are constants tuned experimentally
C
C
P
I
and
=
=
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Figure 11. Basic Concept of Torque Limitation
C
C
1
3
Equation
+
+
C
C
2
4
⋅
⋅
ω
ω
m
m
8. The measured speed can be updated only when
P
Ui
U
ef
U
P
ef
C
Z
I
lim
Figure
11. The torque
U
Z
voltage
limitation
MOTOROLA
Equation 7
Equation 8