Induction Motor Drives

1. SOLID STATE DRIVES
1
INDUCTION MOTOR DRIVES

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

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

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

5. ConventionalRotorResistance
Control
5

6. ConventionalRotorResistance
Control

7. ConventionalRotorResistance
Control
7

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

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

10. StaticRotorResistanceControl
⚫
10

11. StaticRotorResistanceControl
11

12. StaticRotorResistanceControl
12

13. StaticRotorResistanceControl
13

14. StaticRotorResistanceControl
14

15. StaticRotorResistanceControl
15

16. StaticRotorResistanceControl

17. StaticRotorResistanceControl

18. StaticRotorResistanceControl

19. Characteristics with Rotor Resistance Control
19

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

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

23. 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