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.
P 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 P 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
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
A P-based system consists of many components: CPU. Memory. I/O:
disk drives, keyboard, mouse. System Bus. Supporting circuitry.
All components communicate using System Bus.
Master of all components. Job: Get instructions from memory.
Execute instructions. Perform calculations (may use math
co-processor). Control bus operations.
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).
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
Input/Output. Connects P with external devices: Add
functionality to P.
Interfaces with P using ports. Examples: Keyboard. Mouse.
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
electricdrive 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 technique. Problem of switching losses. High insulation
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
3-phase AC SupplyLine synchronizing circuit
Thyristor to be triggred
Firing angle Evaluation Timer And logic
Four quadrant logic
Motor Current Speed Signal
Speed ComparatorRefrence speed
start Initialization Start comman no d? yes Read reference speed
Read motor speed Calculate speed error & current reference
Torque reversal ? yes no no Stop sequence Changeover sequence
stop Comman d? yes
Read motor current Compute current error Compute firing angle
& output firing signal