The document outlines the design of a control system for a DC motor using the AVR Atmega32 microcontroller, focusing on PID control and pulse width modulation to maintain constant speed under varying loads. It describes the technical specifications of the motor and microcontroller components, as well as the use of an incremental encoder for position feedback. The system is designed for flexibility in control through a user-friendly interface with an LCD display and keypad.

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Date:- 26th May-2012

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Guide: Prepared by:
External Guide:-Mr.Ashok Fadnis Alok Shah
Internal Guide:-Ms.Manisha Mayavanshi

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Research & Consultant Company in Instrumentation
Major Working Fields: Power Electronics & Embedded Systems
Main Products:-
 Medical Instruments
 Welding Machines
 Bagging Machines
 Batching Machines
 Servo Systems
 Analytical Pharmaceutical Equipments

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 The main core of this project is to design a control
system for DC motor by using Microcontroller.
 This control system works on the principle of PID
Controller and Pulse Width Modulation which will be able
to control the DC motor speed at desired speed regardless
the change of load.
 This system will be also able to perform operations
like start and stop on motor at desired position of load.

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LCD Display Power Supply:
Controller-AVR ATMEGA32 S1 S2
DUTY CYCLE
Control Menu
PWM H Bridge M
S3 S4
Open Loop S1,S4
Hi-Lo Forward
RPM (Speed) S2,S3
DIRECTION
Position
Direction Counter
E D U S ENCODER
KEYPAD MOTOR

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LCD & KEYPAD:
Keypad: 4*1, LCD: 16*2
LCD to display i/p ,o/p & Appropriate Messages
Keypad to take i/p from User
KEY NO. OPERATION
B1 Start/Stop
B2 Increment (Up)
B3 Decrement (Down)
B4 Esc

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MICROCONTROLLER: TECHNICAL SPECIFICATIONS OF
AVR-ATMEGA32
Software Module of Project
Core Size 8 bit
We use… AVR ATMEGA32
Speed Up to 8MHz
Specially Designed Instructions
Program Memory (Flash) 32Kbytes
PWM Generation Modes
Voltage Supply 2.7V ~ 5.5V
 Normal Mode
Oscillator Internal (8MHz)
 CTC Mode
Operating Temperature -40°C ~ 105°C
 Phase Correct PWM Mode
Package 40-SOIC
 Fast PWM Mode
 Programmed for Four Separate Controls
(Programming Scenario: PID Algorithm)

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MOTOR DRIVER: Main Switching Module (Made of two Parts)
1) Power Circuit:-
 Require to generate 24Vdc  Require to generate 5Vdc
Main Supply Main Supply
Step-down Transformer
Step-down Transformer
Diode Bridge & Filter
Bridge Rectifier
To Control Voltage Regulator To µC &
Filter
Circuit (LM-7805) Optocoupler

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2) Control Circuit:-
 Require to control the motor..
From Microcontroller
Optocoupler-1 Optocoupler-2
(6N137) (6N137)
Power MOSFET (IRFZ46N) NPN Transistor (BC547)
Duty Cycle Direction
Control Control
DPDT Relay (2C/O MCC 24D) To Motor

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Formed using
DPDT Relay
NC1 NC2 NC3 NC4 OPERATION
1 0 0 1 Motor moves right
0 1 1 0 Motor moves Left
0 0 0 0 Motor free runs
0 1 0 1 Motor breaks
1 0 1 0 Motor breaks

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DC MOTOR:- TECHNICAL SPECIFICATIONS OF
PMDC MOTOR
Permanent Magnate Type
Supply Voltage 24Vdc
Advantages:
Power 50W
 Low initial cost
Current 2A
 Easy to Control Speed
RPM 3200
Disadvantages:
Outer Dia. 60mm
 High maintenance
Length 100mm
 Low torque generation
Shaft Dia. 8mm
 Speed Control Using PWM
 Pulse Width increases=Speed increases
 Pulse Width decrease=Speed decreases

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DIGITAL FEEDBCK MECHANISM:-
To form the Close loop for Position Control
We use… Incremental Encoder
One Rotation=One Pulse
One Revolution=512 Pulses
Generate Quadrature Pulses with 90 Shifting

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How µC-Count(Position) is trigger??
TECHNICAL SPECIFICATIONS OF
H ENCODER
Supply Voltage 4.5V ~ 5.5V
L
PPR 512
Ref. Voltage 2.48V
Output Voltage 4.5V ~ 5.5V
FROM TO FROM TO
Supply Current 65mA ~ 91mA
0,1 1,1 0,1 0,0
Ambient Temperature 24°C
1,1 1,0 1,1 1,0
Body Dia. 50mm
1,0 0,0 1,0 1,1
Shaft Dia. 6mm
0,0 0,1 0,0 1,0
No. of Output 2 (AB)
Forward=Count Up Reverse=Count Down

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Output Across Input
24VDC Capacitor 230VAC

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20V
Duty Cycle
At 50%
10V
0V
-10V
0s 2ms 4ms 6ms 8ms 10ms 12ms 14ms 16ms
V(Q3:c,Q6:c)
Time
20V
Duty Cycle
At <50%
10V
0V
-10V
0s 2ms 4ms 6ms 8ms 10ms 12ms 14ms 16ms
V(Q3:c,Q6:c)
Time
20V
Duty Cycle
At >50%
10V
0V
-10V
0s 2ms 4ms 6ms 8ms 10ms 12ms 14ms 16ms
V(Q3:c,Q6:c)
Time

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At 50% At >50% At <50%
Duty Cycle Duty Cycle Duty Cycle

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RPM
Duty Cycle

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At No Load Condition
At Minor Load Condition

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Used in any

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 Same circuit can be used for stepper motor control..
 GSM Module can be used to make the control possible with
mobile messages..
 This system can be used in industrial controlling drives because of
its improved accuracy and fast dynamic response just by modifying
following issues:-
 Feedback Measurement (Encoder)
 Control Algorithm (Microcontroller)
 Switching Module (Motor Driver Circuit)

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 The direction (forward/reverse) of the motor is also controlled.
 Control and operation of drive is flexible due to the user friendly
menu, keyboard and LCD display.
 The speed of the motor is controlled accurately using
microcontroller ATmega32 having PID algorithm.
 In the condition of the load variation the speed of the motor is
maintained constant with the designed algorithm.
 Position is controlled accurately using PID algorithm and
feedback pulses from the encoder in order to develop a precise
system.

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