AN1931D Freescale Semiconductor / Motorola, AN1931D Datasheet - Page 11

• Manufacturer Part Number: AN1931D
• Description: 3-Phase PM Synchronous Motor Vector Control
• Manufacturer: Freescale Semiconductor / Motorola

MOTOROLA
3.3.2 Block Diagram of Vector Control
Speed
ommand
In this method, we must break down the field-generating and torque-generating parts of the stator
current to be able to separately control the magnetic flux and the torque. In order to do so, we need to
set up the rotary coordinate system connected to the rotor magnetic field; this system is generally
called a “d-q coordinate system”. Very high CPU performance is needed to perform the transformation
from rotary to stationary coordinate systems. Therefore, the Motorola DSP56F80x is very well suited
for use in a Vector Control algorithm. All transformations which are needed for Vector Control will be
described in the next section.
Figure 3-6
Vector Control, follow these steps:
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•
•
•
•
•
•
•
•
Figure 3-6. Block Diagram of PM Synchronous Motor Vector Control
Measure the motor quantities (phase voltages and currents)
Transform them into the two-phase system (
Calculate the rotor flux space vector magnitude and position angle
Transform stator currents into the d-q coordinate system using Park transformation
The stator current torque- (i
by the controllers
The output stator voltage space vector is calculated using the decoupling block
The stator voltage space vector is transformed back from the d-q coordinate system into the
two-phase system and fixed with the stator by inverse Park transformation
Using sinewave modulation, the output 3-phase voltage is generated
Speed
U Sd
shows the basic structure of Vector Control of the PM synchronous motor. To perform
U Sq
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-
Freescale Semiconductor, Inc.
3-Phase PM Synchronous Motor Vector Control
For More Information On This Product,
I Sq
I Sd
Go to: www.freescale.com
sq
Transformation
Forward Park
U
U
) and flux- (i
Sq_lin
Sd_lin
U Sd
U Sq
sd
) producing components are controlled separately
) using Clarke transformation
U
I S
I S
U
S
S
Forward Clarke
Transformation
Generation
Sinewave
pwm a
pwm b
pwm c
Target Motor Theory
I
I
I
Sb
Sc
Sa
3-phase Power Stage
Position
Line Input
Position/Speed
sensor
PMSM
motor
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