Presentation:
AC Servo Motor Control with QEP Module
by EZDSP2812
Professor: Chen, Pei-Chung
陳沛仲
Student: Thanh-Nhan Nguyen
阮誠仁
2009, February, 12th
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1. The control system
2. Block diagram of the system
3. Program flowchart
4. RPM caculation and sampling time
5. Result
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110 VAC
DSP2812
AC Servo Motor
AC servo
Motor
Driver
Fig 1. AC Servo Motor drive implementation
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 Generate PWM pulse
 Control the AC Servo motor
 Get the encoder signal
 Calculating the speed
Processing…
Prom PC
AC Servomotor
Driver
Get the encoder
pulses
Speed
Calculation
Fig 2. The steps for AC Servo Motor control and speed estimation
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AC Servo Motor Driver
PWM
generating
110VAC
AC Servo Motor
Fig 3. Overall block diagram of sensored speed control of AC servo motor
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Initialize System Control
Initialize GPIO
Clear all interrupts and initialize PIE vector table
Initialize all the Device Peripherals
Specific code for QEP module and pulse calculation
Duty cycle and RPM calculation
Fig 4. The procedure to initiate QEP and pulse calculating process
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A
A
Fig 5. Program flowchart
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 Measure the duty cycle function
 Calculating the speed of AC Servo Motor (RPM)
+ Encoder lines = 2000
+ RPM = (Pulses in 1 second) / 2000
 Sampling rate: f = 20000 Hz
 Sampling period: T = 1/f = 1/20000 (s) = 0.05 ms = 50us
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a)
b)
Fig 6. a) The speed of AC servo motor ( open-loop control)
b) The duty cycle function
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a)
b)
Fig 7. a) The speed of AC servo motor ( closed-loop control)
b) The duty cycle function
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Fig 8. The difference between open-loop control
and closed loop control
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Thank you very much
for your listening!
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