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Presented By
Md Manzar Nezami Md Mustafa kamal
A microprocessor is an electronic device that consists of millions (or billions) of transistors packed into one IC.
Its function is to execute instructions in the form of programs, calculate and store its results.
Microprocessors are used widely in our everyday lives.
µP is a complex, powerful device:◦ Able to process huge amounts of data.◦ Built using transistors etched on silicon die.◦ Needs external components to support operation.
Microcomputer system – support µP operations.
The microprocessor can be used to perform complex operations by giving it instructions.
These instructions are called programs. Programs are loaded into memory, and are
executed line-by line by the microprocessor.
Definition: A complete electronic system built around the microprocessor to support the microprocessor operation.
May consist of CPU, memory, I/O (disk drives, keyboard, mouse), system bus, and supporting circuitry.
CPU as the “brain” – controls actions of all components.
ROM
Keyboard Mouse HDD
Floppy RAM
CD-ROMSupporting
CircuitryCPU
Keypad
Memory
Power Supply LCD DisplayCPU
A µP-based system consists of many components:◦ CPU.◦ Memory.◦ I/O: disk drives, keyboard, mouse.◦ System Bus.◦ Supporting circuitry.
All components communicate using System Bus.
Parallel I/O Serial I/OInterrupt
Circuit
Timing CPU Memory
System Bus
“Master” of all components. Job:
◦ Get instructions from memory.◦ Execute instructions.◦ Perform calculations (may use math co-
processor). ◦ Control bus operations.
CPU
CPU consists of:◦ ALU (Arithmetic/Logic Unit):
Performs arithmetic/ logic computations.◦ CU (Control Unit):
Responsible to retrieve instructions, analyze, then execute.
◦ Registers: Fast internal storage. Used to temporarily store addresses, data, processor
status.
Stores instructions and data for CPU. Each memory location given unique
address.◦ CPU refers to address to access.
Types: ◦ Read-Only Memory (ROM).◦ Random-Access Memory (RAM).◦ Non-Volatile Memory (NVM).
Memory
Synchronizes all components in the system.◦ All components refer to the clock timing for
operations. Generates square waves at constant
intervals. Crystal oscillator + timing circuitry. Higher clock speed allow computers to
function faster.
Timing
Input/Output. Connects µP with external devices:
◦ Add functionality to µP. Interfaces with µP using ports. Examples:
◦ Keyboard.◦ Mouse.◦ Display monitor.
Built into board
Using card slots.
An electric motor together with its control equipment and energy transmitting device forms an Electric Drives. Some examples of electric-drive systems are: A ceiling fan motor with regulator and also with blades, a food mixer with food to be processed, a motor and conveyer belt with material on its belt and so on.
Electric drives are mainly two types:- DC Drives AC drives
AC drives are those in which motive power provided by ac motors. Though speed control of dc motors is easy as compared to ac motors, but ac motors have some advantages which outweighed the advantages of dc motors, and so with the development of different techniques of speed control of ac motor drives, now days, ac motor drives are more extensively use in industries.
Low maintenance cost. AC drives have a better power factor in most
applications. Harmonics reduction is cheaper in case of AC
drives. Higher transient response capability. AC drives are of lower cost in comparison to
DC drives.
High braking cost. Complex braking strategy. Complex and expensive speed control
technique. Problem of switching losses. High insulation cost.
Two types of controlling
Hardwire control
Electronic control/digital control
Small size Fast response Less power consumption Accurate and efficient Controlling range increased System reliability is much more than
conventional one. economical
Control of 4-quadrant micro computer controlled dc drive system
Thyristor to be triggred
Current comparator
Four quadrant logic
Speed Comparator
Current control
Speed Control
Firing angle Evaluation
Line synchronizing circuit
Timer And logic
Pulse Ampli-fier
Motor Current
D A
D ASpeed Signal
Refrence speed Start/stop
Microcomputer
3-phase AC Supply
W
Fig. Schematic 4-Quadrant microcomputer controlled D.C. drive System
M
stopComma
nd?
stop
Changeover sequence
Torque reversal
?
Compute current error
Read motor current
Compute firing angle & output firing signal
Start comman
d?
start
Read reference speed
Calculate speed error & current reference
Initialization
Read motor speed
Stop sequence
noyes
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yes
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