AN1917D Freescale Semiconductor / Motorola, AN1917D Datasheet - Page 4

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

4
Target Motor Theory
3.
The PM Synchronous motor application utilizes the Quadrature Decoder connected to Quad Timer
module A. It uses the Decoder’s digital input filter, to filter the Encoder’s signals, but does not make use
of its decoding functions, so the decoder’s digital processing capabilities are free to be used by another
application.
The PM Synchronous motor is a rotating electric machine where the stator is a classic three phase
stator like that of an induction motor and the rotor has surface-mounted permanent magnets (see
Figure
In this respect, the PM Synchronous motor is equivalent to an induction motor where the air gap
magnetic field is produced by a permanent magnet. It means that the rotor magnetic field is constant.
PM Synchronous motors provide a set of advantages for designing modern motion control systems.
The use of a permanent magnet to generate a substantial air gap magnetic flux makes it possible to
design highly efficient PM motors.
The PM Synchronous motor is described by the following equations:
where
Target Motor Theory
3-1).
u
i
r
S
S
S
Figure 3-1. PM Synchronous Motor - Cross Section
T
e
=
3-Phase PMSM Control with Quadrature Encoder
i
Freescale Semiconductor, Inc.
S
is the space phasor of stator voltage
is the space phasor of stator current
is the stator phase resistance
For More Information On This Product,
S
sin
Go to: www.freescale.com
u
i
S
S
S
=
=
L
r
S
S
S
i
i
=
S
S
+
+
i
d
--------- -
S
dt
M
S
M
sin
i
S
M
Stator
Stator winding
(in slots)
Shaft
Rotor
Air gap
Permanent magnets
MOTOROLA
(EQ 3-1.)
(EQ 3-2.)
(EQ 3-3.)