SOLID STATE DRIVES
1
INDUCTION MOTOR DRIVES

Contents
2
⚫ Speed control by Variable Voltage method
⚫ speed control by rotor resistance variation
⚫ Slip Power Recovery Schemes
⚫ Closed Loop Control
⚫ Vector Control
⚫ Applications

RotorResistanceControl
3
Disadvantages
1. Heavier
2
. HighCost
3
. HighInertia
4
. HighSpeedlimitation
5
. HighMaintenance

TY
PESOFROTORRESISTANCE
CONTROL
4
⚫ Conventional
⚫ StaticRotorR
esistanceControl
⚫ SlipPowerRecoveryS
c
h
e
m
e

ConventionalRotorResistance
Control
5

ConventionalRotorResistance
Control

ConventionalRotorResistance
Control
7

Disadvantages
8
⚫ R
educedEfficiency
⚫ Speedc
h
a
n
g
e
swithloadvariations
⚫ Unbalanceinvoltageandcurrent

SeveralAdvantages
9
⚫ Absenceofin-rush current
⚫ Highstartingtorque
⚫ Highlinepowerfactor
⚫ Absenceoflinecurrentharmonics
⚫ Smoothandwiderangeofspeedcontrol

StaticRotorResistanceControl
⚫
10

StaticRotorResistanceControl
11

StaticRotorResistanceControl
12

StaticRotorResistanceControl
13

StaticRotorResistanceControl
14

StaticRotorResistanceControl
15

StaticRotorResistanceControl

StaticRotorResistanceControl

StaticRotorResistanceControl

Characteristics with Rotor Resistance Control
19

speed control by rotor resistance variation
Block Diagram for Rotor Resistance Control
21

Features
⚫ Speed Range
⚫ Braking
⚫ Harmonics
⚫ Torque Pulsations
⚫ Good pf
⚫ Poor Efficiency
⚫ Reasonable Cost
⚫ General
22

Draw backs of Stator Voltage Control and Rotor
Resistance Control
23
● Poor Efficiency at low speed.
● Limited range of Speed Control
● Slip power is wasted in the Motor
● Resistances in Stator Control and in Rotor
Resistance in Rotor Resistance control