AN1917D Freescale Semiconductor / Motorola, AN1917D Datasheet - Page 9

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

Freescale Semiconductor, Inc.
Target Motor Theory
Figure 3-7. Alignment of Rotor Position
3.1.4 Speed Control
The correct shift between the rotor and stator flux ensures that the PM Synchronous motor generates a
torque. The torque amplitude depends on the amplitude of the applied voltage. It means that the motor
speed is also controlled by the amplitude of the applied voltage. The amplitude of the applied voltage
is changed by the PWM technique. The required speed is controlled by a speed controller. The speed
controller is implemented as a conventional PI controller. The PI controller compares the actual and
required speeds. The difference between the actual and required speed is input to the PI controller and
based on this difference. The PI controller calculates the duty cycle which corresponds to the voltage
amplitude required to keep the required speed.
Power Stage
Sinewave
Amplitude
error
Speed
PWM
Controller
Generator
-
Sinewave
actual
Generation
Rotor Position
Figure 3-8. Speed Controller
MOTOROLA
3-Phase PMSM Control with Quadrature Encoder
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