Electrical Drives and Control

Features Includes:

  • 176 - 3D/2D Animation
  • 580 Pages of Content
  • 60 Lecture Hours
  • 33 Solved Problems
  • 68 Quiz
  • Suitable for All Technical University Syllabus

Course Description

This learning solution deals with the drive motor characteristics and its starting methods. And also it explains the conventional and solid state control of D.C. and A.C. drives.

OBJECTIVES:

  • To understand the basic concepts of different types of electrical machines and their performance
  • To study the different methods of starting D.C motors and induction motors
  • To study the conventional and solid-state drives
UNIT 1 - INTRODUCTION

Basic elements of electric drive- Block diagram of electrical drive systems - Comparison between A.C. drives and D.C. drives. Types of electric drives - Classification of electrical drives - Comparison between group drive and individual drive - Applications of electrical drives - Factors influencing the selection of electric drives. Heat and Cooling time curves - Heat curve - Problems. Load condition and classes of duty- Selection of motor based on load variation. - Types of loads for which drives are needed - Intermittent periodic duty - Load curves of different types of loads. Selection of power rating of drive motors - Selection of power rating for drive motors - Method based on average losses - Motor ratings for other duty cycles. Selection of motor for industrial application - Comparison of A.C. and D.C. drives - Four quadrant operation of a drive - Selection of motor for miscellaneous applications.

UNIT 2 - DRIVE MOTOR CHARACTERISTICS

Introduction - D.C. motor principle - Working of D.C. motor. Back emf - Signification of the back E.M.F - Importance of back E.M.F. Speed and torque equation - Torque equation - Speed-torque equation - Problems based on motor torque and speed. Types of D.C. motor - Classification of D.C. motor - D.C. series motor – Problems – D.C. shunt motor – Problems - D.C. compound motor. Characteristics - D.C. Motor characteristics - Characteristics of D.C. shunt motor - Characteristics of D.C. series motor - Characteristics of D.C. compound motor - Application of D.C. motors. Introduction to three phase induction motor - Advantages and disadvantages of induction motor. Working Principle of three phase induction motor - Working principle of three phase induction motor. Production of rotating magnetic field - Graphical representation of resultant rotating flux. Slip and Effect of slip on rotor parameters - Slip and slip speed – Problems - Effect of slip on rotor parameters - Rotor reactance, resistance and impedance - Rotor current and power factor – Problems. Construction of three phase induction motor - The stator - Squirrel cage rotor - Phase wound or slip ring rotor - Comparison of squirrel cage and slip ring induction motor - Application of induction motor. Phasor diagram of induction motor - Phasor diagram of induction motor. Concept of equivalent circuit - Determination of equivalent circuit constants by conducting no load test and blocked rotor test - Blocked rotor test - Equivalent circuit - Torque equation - Torque of 3 phase induction motor - Starting torque of three phase induction motor - Starting current Ist - Condition to obtain maximum starting torque - Torque of induction motor under running condition – Problems. Torque-Slip characteristics - Slip torque characteristics of three phase induction motor - Speed-torque characteristics - Effect of change in rotor resistance on torque - Effect of change in voltage and frequency. Power stages, losses and efficiency of three phase induction motor - Losses in an induction motor - Power transfer stages (or) power flow diagram of an induction motor - Relationship between rotor input, rotor copper losses and rotor output - Efficiency of an induction motor – Problems. Single phase induction motors - Introduction to single phase induction motor – Construction - Working principle - Why is single phase induction motor not self starting - Starting of single phase induction motor - Double field theory and Cross field revolving theory - Double field revolving theory - Cross field theory . Types of single phase induction motor - Classification of single phase motor - Split-phase single phase induction motor. Capacitor start type induction motor - Capacitor-start single phase induction motor. Capacitor run type induction motor - Capacitor run single phase induction motor. Capacitor start capacitor run induction motor - Capacitor start capacitor run single phase induction motor. Shaded pole induction motor - Shaded pole single phase induction motor. Electric braking - Comparison between Mechanical and Electrical Braking - Plugging of D.C. shunt motor - Plugging of D.C. series motor - Plugging of three phase induction motor – Problems. Dynamic braking - Rheostatic braking of D.C. shunt motor - Rheostatic braking of D.C. series motor. Regenerative braking - Regenerative braking of D.C. motor - Regenerative braking of induction motor - Braking of three phase induction motor.

UNIT 3 - STARTING METHODS

Necessity of starter - Three point starter - Function of no volt coil - Action of over load release - Speed control - Four point starter - Necessity of the starter for D.C. series motor - Drum controlled starter - Calculation of step of starter resistance – Problems. Automatic starter - Electronic starter - Advantages of Electronic Starter. Starting of three phase induction motor - Starting of induction motor - Direct-switching or line starting of induction motors - Necessity of starting - D.O.L. starter - Star to delta starter - Auto-transformers - Relation between starting and Full load torque - Stator resistance starter - Rotor resistance starter. Electronic starter - Electronic Starters (Soft Starter) - Wound rotor induction motor starter using frequency sensing relays.

UNIT 4 - CONVENTIONAL AND SOLID STATE SPEED CONTROL OF D.C. DRIVES

Speed control of D.C. shunt motor - Necessity of speed control - Methods of speed control - Armature voltage control method - Voltage control method – Problems. Speed control of D.C. series motor - Speed control of series motor – Problems. Introduction to power electronic devices - Introduction of power electronics - Types of thyristor family devices - ISI circuit symbol for power semiconductor devices - Advantages and disadvantages of power electronics - Applications of power electronics - Power electronic devices. Power diodes - Types of power diodes - Basic structure of power diodes - I-V Characteristic of power diode (Static characteristics) - Switching characteristics (Dynamic characteristics) - Advantages, disadvantages and applications of power diodes - Power diode as freewheeling diode - Series and Parallel Connected Diodes - Parallel configuration. Silicon Controlled Rectifier (SCR) - Introduction of SCR - Constructional details of SCR - Operation of SCR - Static characteristics of SCR - Two transistor analogy of SCR. Power BJT - Introduction to Power BJT - V-I characteristics of power BJT - Operation of power transistor - Switching characteristics of power BJT - Turn off characteristics - Safe operating area - On state losses in a power transistor - Thermal runaway - Merits of a power BJT. Power MOSFET - Structure of a power MOSFET - Principle of operation - I-V characteristics (Static characteristics) - Switching characteristics of power MOSFET - Switching model of MOSFETs - Merits, demerits and applications of power MOSFET. Classification of converter - Introduction - Classification of converters – Converter. Single phase half wave controlled converter - Single phase half-wave controlled converter with R load - Single phase half wave controlled converter with RL load - Need for freewheeling diode - Single phase half wave controlled converter with free wheeling diode. Single phase half controlled converter (Semi converter ) - Semi converter or Half controlled converter - Single phase semicontrolled converter with the R – load - Single phase semicontrolled converter with highly inductive load - Mode III - Single phase half controlled full converter with R load - Semi converter with freewheeling diode - Mode III - Single phase semi converter driving RLE load. Single phase fully controlled converter - Single phase fully controlled converter with R load - Single phase fully controlled full converter with RL load - Single phase full converter RL load with freewheeling diode. Principle of chopper – Introduction - Classification of choppers - Working principle of chopper - Control strategies of choppers - A.C. link and D.C. link chopper. Type A,B,C,D chopper - Classification of choppers - Class A chopper - Class B chopper - Class C chopper - Class D chopper - Four quadrant operation (Regenerative breaking mode). Introduction to D.C. motor speed control - Introduction to D.C. motor speed control - Closed loop control of D.C. drives. Single phase drive - Single phase semi converter drive - Single phase half wave converter drives - Single phase fully controlled rectifier drive - Single phase dual converter drive. Single phase semi converter drive - Single phase semi converter drive for speed control of D.C. series motor - Single phase Full converter drive for speed control of D.C. series motor. Three phase drive - Three phase drives - Three phase semi converter drive - Three phase full converter drive - Three phase dual converter. D.C. chopper drives - Introduction to Chopper control of D.C. motor - Speed control of D.C. Series motor using chopper - Speed control of D.C. Shunt motor using chopper - Comparison of converter controlled D.C. drive and chopper controlled D.C. drive - Chopper fed D.C. series motor drive.

UNIT 5 - CONVENTIONAL AND SOLID STATE SPEED CONTROL OF A.C. DRIVES

Speed control of 3 phase induction motor – Introduction - Supply frequency control or V/f control - Supply voltage control - Advantages, disadvantages and applications of IGBT - Multiple stator winding method - Adding rheostats in stator circuit - Adding external resistance in rotor circuit - By injecting voltage into the rotor circuit - Cascade control method - Slip power recovery scheme - Kramer system - Scherbius method. Inverter - Introduction to inverter - Classification of inverters - Applications of inverter. Voltage source inverter - Single phase half bridge inverter - Single phase full bridge inverter. Voltage control and PWM techniques of inverters - Voltage control of single and three phase inverters - Control of DC voltage supplied to an inverter - Control of voltage within inverter using PWM technique - Single pulse width modulation (SM) [Quasi Square Output] - Single pulse width modulation (SM) [Quasi Square Output] - Symmetrical multiple pulse width modulation - Multiple pulse modulation with selective Elimination of harmonics (MMSR) - Sinusoidal pulse width modulation (SPWM) - Features of SPWM - Modified sinusoidal pulse width modulation (MSPWM) - PWM Techniques. Current source inverter - Introduction to current source inverter - Single phase CSI with purely inductive load - Three phase current source inverter - Comparison of transistorised and thyristorised inverter. Introduction to A.C. voltage controller - A.C. voltage controller - Principle of On-off control (Integral cycle control) - Principle of phase angle control - Classification of controllers with phase angle control. Single phase half wave and full wave A.C. voltage controller - Single phase half wave A.C. voltage controller (Unidirectional controller) – Problem - Full wave AC voltage controller with resistive load(Bi-directional controller) - Analysis of full wave controller - Problem - Bidirectional AC voltage controller with RL load - Interval V - Full wave AC voltage controller with only one SCR. Stator voltage control - Stator frequency control. Speed control of induction motor using voltage source inverter - Constant torque and constant power operation - Stator current control. Cycloconverter fed induction motor drive - Static rotor resistance control. Static Slip power recovery scheme - Slip power recovery scheme - Static Kramer drive - Static Scherbius method - Cycloconverter Scherbius drive.