AN1917D Freescale Semiconductor / Motorola, AN1917D Datasheet - Page 12

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

12
System Concept
4.3 Hardware Implementation
The control process is as follows:
The state of the user interface is periodically scanned while the speed of the motor is measured on each
new coming edge from the Quadrature Encoder (only one phase is used for speed measurement).
According to the state of the control signals (Start/Stop switch, speed up/down buttons) the speed
command is calculated. The comparison between the actual speed command and the measured speed
generates a speed error. The speed error is brought to the speed PI controller that generates a new
corrected amplitude of the sinewave output. The rotor position is also periodically scanned together
with sinewave generation. The sinewave generation generates 3-phase sinewaves, shifted by 120
electrical degrees according to actual rotor position and the required amplitude. The output of
sinewave generation defines directly the duty cycle of the PWM output signals for the power stage.
In the case of under-voltage, the PWM outputs are disabled and the fault state is displayed by an
on-board LED.
As already stated, the application runs on Motorola motor control DSPs using the DSP EVM Boards
and a dedicated 3-phase AC/BLDC platform.
The application can be controlled by the following Motorola motor control DSPs:
The application can run on an EVM motor board.
DSP56F80xEVM
•
•
•
PC Master
Control SW
START
DOWN
STOP
UP
DSP56F803
DSP56F805
DSP56F807
DSP56F80x
R
S
2
3
2
G
P
O
I
3-Phase PMSM Control with Quadrature Encoder
Freescale Semiconductor, Inc.
For More Information On This Product,
Controller
PI
Required
Speed
Figure 4-1. System Concept
Go to: www.freescale.com
Generation
SINWAVE
Calculation
Speed
P
W
M
M
D
E
C
O
D
E
R
E
R
T
I
Quadrature Encoder
Signals
PWM1-6
Motor Board
12V DC
BLDC
Motor
EVM
MOTOROLA