Water Industry Process Automation & Control Monthly - April 2024
Advanced Electrical Drive Controls, Types and Implementation”
1. Presented by
Dr. R. RAJA, M.E., Ph.D.,
Associate Professor, Department of EEE,
Muthayammal Engineering College, (Autonomous)
Namakkal (Dt), Rasipuram – 637408
MUTHAYAMMAL ENGINEERING COLLEGE
(An Autonomous Institution)
(Approved by AICTE, New Delhi, Accredited by NAAC, NBA & Affiliated to Anna University),
Rasipuram - 637 408, Namakkal Dist., Tamil Nadu, India.
“Advanced Electrical Drive Controls, Types
and Implementation”
2. Contents
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Dept of EEE/MEC
Block Diagram of Electrical Drive
Types of Electrical Drives
Based on Supply
• AC Motor drives
• DC Motor drives
Based on Number of Motors
• Individual
• Multi Motor
• Group Drive
Based on Speed
• Constant Speed drive
• Variable Speed drive
Based on Control Parameters
• Vector Control Drive
• Constant Power Drive
• Constant Torque Drive
Advantages of Electrical Drives
Disadvantages of Electrical Drives
Applications of Electrical Drives
3. Introduction
An electrical drive is defined as an electronic device designed to control
certain parameters of the motor for controlling the electrical energy into
mechanical power in a precise controllable way.
Electrical power systems employed for motion control are called “Electrical
Drives”.
It consists of a classy electronic system or a combination of different systems
for the purpose of motion control.
Motion is provided with the help of prime movers.
Example of prime movers are Petrol engines, Diesel engines, gas or steam
turbines, steam engines, hydraulic motors, and electric motors.
Drives power systems employing electric motors are known as electric drives.
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4. Block Diagram of Electrical Drive
A modern electrical drive capable of variable controlled speed is made of
some important parts as shown in the below block diagram.
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5. Source: Source can be DC or AC source.
Power converter: AC to DC, AC to AC, DC to DC, DC to AC converters.
Motor: Converts electrical energy in to mechanical energy, it is the heart of the
electrical system.
Commonly used motors are
DC motors – series, shunt/parallel DC motor, compound and permanent magnet
DC motor.
Induction motors – wound rotor and linear, squirrel cage.
Brush less dc motors
Stepper motors.
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Contd..
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Load: It can be a machine to accomplish a given task. Example is Pump, Fan,
Machine tools.
Controller: The power required for the motor is supplied by the controller.
Sensor: Depending upon the type of control required, various inputs from sensors
are taken. An example is a speed, current.
8. AC Motor drives
AC drive is a device used to control the speed of an electric motor such as a
three-phase induction motor by changing the frequency of the electrical supply
to the motor.
AC drive is also called Variable Frequency Drive (VFD) or Variable Speed
Drive (VSD).
DC Motor drives
It is basically speed control system of a DC electrical motor that supplies
voltage to the motor to operate at desired speed.
DC drives are classified as analog DC drives and digital DC drives.
Digital DC drive can offer precision control.
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Based on Supply
9. Based on Number of Motors
Individual
There will be a separate drive motor for various parts of a machine.
Example: Lathe machine.
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10. Multi Motor
Separate motors are provided for actuating different parts of a machine.
Example: Cranes.
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Contd..
11. Group Drive
In a group drive, one motor is used as a drive for two or several machines.
The motor is connected by a single shaft, other machines are connected to the
shaft by belts and pulleys.
Group drive is most economical.
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Contd..
12. Based on Speed
Constant Speed drive
Machine tools require more or less constant speed drives, squirrel cage
induction motor along with the manual controls are used.
Variable Speed drive
The main purpose of variable speed drive is to control speed along with
acceleration, deceleration, torque and finally the direction of machine.
They are used to reduce power consumption.
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13. Based on Control Parameters
Vector Control Drive
Vector control is most accurate than any other kind of variable frequency drive
(VFD).
In this control mode, torque and speed controlled using pulse width modulation
(PWM) techniques in an inverter.
These are used for AC synchronous and induction motors.
Constant Power Drive
When a motor while carrying rated current in its armature provides constant
power at all speeds in a certain range of speed control it is known as constant
power drive in that range of speed control.
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14. Constant Torque Drive
Constant torque load type drive is distinctive when fixed volumes are being
handled.
Examples are screw compressors, feeders, and conveyors.
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Contd..
15. Advantages of Electrical Drives
Enough overload capacity without loss of life of machine.
Four quadrant operation.
Modifiable torque-speed characteristics.
No requirement of warming up period.
Higher efficiency.
Easy control.
Clean operation, no pollution.
Wide range of speed control.
Electric braking can be employed
They can be started instantly and immediately can be fully loaded.
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16. Disadvantages of Electrical Drives
High initial cost due to the presence of power converters and controller
electronics.
Regular maintenance and high attention are required.
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17. Applications of Electrical Drives
Industrial Production,
Manufacturing, and
Process Control.
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