AN1917D Freescale Semiconductor / Motorola, AN1917D Datasheet - Page 5

• Manufacturer Part Number: AN1917D
• Description: 3-Phase PM Synchronous Motor Control with Quadrature Encoder Using DSP56F80x
• Manufacturer: Freescale Semiconductor / Motorola

MOTOROLA
3.1 Digital Control of a PM Synchronous Motor
As can be seen from equation
placed ± 90° relative to the rotor permanent magnet flux space vector. This situation is shown in
Figure
where
A PM Synchronous motor is driven by sinewave voltage coupled with the given rotor position. The
generated stator flux together with the rotor flux, which is generated by a rotor magnet, defines the
torque, and thus speed, of the motor. The sinevawe voltage output have to be applied to the 3-phase
winding system in a way that angle between the stator flux and the rotor flux is kept close to 90° to get
the maximum generated torque. To meet this criterion, the motor requires electronic control for proper
operation.
3-2.
T
R
L
e
e
S
S
S
M
Figure 3-2. Torque Optimal Control of PM Synchronous Motor
3-Phase PMSM Control with Quadrature Encoder
Freescale Semiconductor, Inc.
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is the space phasor of stator magnetic flux
is the space phasor of rotor magnetic flux evoked by the permanent magnet
is the electrical torque
is the stator resistance
is the stator inductance
is the Back-EMF voltage
resultant magnetic flux
u
(EQ
j L
s
s
3-3.), optimal torque is generated when the stator current vector is
i
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s
i
R
e
s
s
i
s
s
90°
M
Target Motor Theory
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