1. Smooth transition between optimal
control modes in
SWITCH RELUCTANCE MOTOR
By- Badal Patnaik - 1001227260
Sanjit Debta - 1001227317
D. Gouri Sankar - 1001227269
Debendra Kido - 1001227267
Ananya Subhadarsinee - 1001227255

2. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

3. Introduction
• Concept of SRM-1938
• Practical realization-mid 1960s,after the evolution of power
electronics & computer aided EM design
• Also known as : -Variable Reluctance Motor
-Brushless Reluctance Motor
-Commutated Reluctance Motor

4. Construction
It’s a doubly-salient, singly-
excited, independent stator
exited motor
The stator is same as PM
motor but the rotor is
simpler having no permanent
magnet
Stator windings on
diametrically opposite poles
are connected in series or
parallel to form one phase

5. Construction
• 6/4,8/4,10/6,12/6,4/2,2/2 etc
configurations are possible, but 6/4 &
8/4 are most common
• Higher the no. of stator/rotor pole
combination, higher the no. of phase
which aide to torque ripple reduction

6. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

7. Principle of Operation

8. Principle of Operation
• Inductance of stator phase winding varies with rotor
position
• Torque is produced only during variation of inductance
• Current is made available only during this variation, hence
the need for rotor position feed back sensor

9. Periodic change of inductance with
Rotor position
Rotor
Unaligned Position
Lu
La
Inductance Profile
Stator
Aligned
PositionRotor
θ1 θ3θ2 θ4
θ
L

10. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

11. Characteristics of SRM
All these characteristics cannot be obtained at a
single operating point.
HENCE THE NEED OF OPTIMAL CONTROL STRATEGY

12. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

13. General Control Strategies
Voltage Source control
Hysteresis current control

14. Voltage Source control
Both transistors are switched on at θ0and both are switched off at θcConducts through D2 and D1 when negative voltage is applied between θc and θq

15. Voltage control waveforms

16. V
Voltage source
Control
Converter
6/4
SRM

V


ω
SRM with voltage source controller

17. Hysteresis current control
• Power switches are switched off or on according to the current is
greater than or less than a reference current.
• The instantaneous phase current is measured and fed back to
summing junction.
• The error is used directly to control the states of power
transistors.

18. Hysteresis current control

19. SRM with hysteresis current controller
iref
Hysteresis Current
Controller
Converter
6/4
SRM 
V

i
i

20. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

21. Modes of operation
Single pulse mode
PWM mode

22. Optimum Performance in Single Pulse mode
L, Ψ
La
L
Lu
Ψc
Ψ
θ
θuθaθqθcθ1
θu
θ0
θ01
θ
βs
βr
αp
θqθcθ1
θu
θ0
θe1 θe2
-Vdc
Vdc

23. Optimum turn-on & turn-off angle in
single Pulse mode
11 e
opt
o c  
  11 1 e
opt
c c  

24. Optimum Performance in PWM mode
La
Lu
L
θ
θ
θ1θu
θ01
i
θ0 θc θq
θe
θa
Vdc
iref
Ψc
-Vdc
θu
βs
βr
αp

25. Optimum turn-on & turn-off angle in
PWM mode
dc
refu
V
iL 
  10
  






e
esk
opt
c


 01
1 12

26. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

27. Simulation block diagram with basic controller

28. Simulation block diagram with developed
controller
Turn-off angle (deg)
Turn-on angle (deg)
powergui
Discrete ,
Ts = 1e-006 s.
peak value
max
peak flux max
Vdc
240
Unaligned ind
-C-
To Workspace2
offangle
To Workspace1
onangle
To Workspace
t
Theta e 1
Theta e
Theta 1
52.5
Theta 01
Switched Reluctance
Motor
TL
m
A1
A2
B1
B2
C1
C2
A1
A2
B1
B2
C1
C2
TL
m
Switch 2
Switch1
Subsystem-4
Theta 1
Theta e1
sp-off
Subsystem-3
Theta 1
Theta e1
sp-on
Subsystem-2
Theta 1
Theta 01
Theta e
pwm-off
Subsystem-1
Theta 1
Theta 01
pwm-on
Scope 1
Ref speed
Signal4
Ref flux
|u|
Position _Sensor
w
alfa
beta
sig
Load torque
Signal 2
-K-
Flux Control
PID
Eqn -3
1/u
Current control
PI
Clock
CONVERTER
G
V+
V-
A1
A2
B1
B2
C1
C2
Base speed 325
Abstract
|u|
240 V
<Flux (V*s)><Flux (V*s)><Flux (V*s)><Flux (V*s)><Flux (V*s)><Flux (V*s)>
<w (rad/s)>
<w (rad/s)>
<I (A)><I (A)>
<Te (N*m)>

29. Block diagram of subsystems
• subsystem-1 • subsystem-1
1
pwm-on
sum
2
Theta 01
1
Theta 1
pwm -off
1
stroke angle
60
constant
1
Subtract 2Subtract 1
Product 2
Product 1
Inv theta e 2
1/u
Theta e
3
Theta 01
2
Theta 1
1

30. Block diagram of subsystems
• subsystem-3 • subsystem-4
1
sp-on
0.25
c-lambda
Pre-eqn
Eqn-sp-on
2
Theta e1
1
Theta 1
1
sp-off
Product0.75
1-c lambda
2
Theta e1
1
Theta 1

31. Parameters of the 6/4 SRM
• Voltage = 240V dc,
• Current = 450A max,
• Rating of the SRM = 60 kw
• No. of phases = 3
• No. of stator poles =6
• No. of stator poles =4
• Rotor pole pitch = 90 deg
• Stator pole arc = 36.00 deg
• Rotor pole arc = 38.50 deg
• Rotor position at which stator
and rotor pole corners starts
overlap =52.50 deg
• Aligned inductance =23.6x10-
03 H
• Unaligned
inductance=0.67x10-03 H
• Max flux linkage=0.486 V.s
• Stator resistance=0.05 ohm
• Inertia=0.05 Kg.m.m
• Friction=0.02 N.m.s
• Base speed = 3100 rpm

32. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

33. Simulation Results
and
Analysis

34. At No-Load with basic controller

35. At No-Load with developed controller

36. At No-Load with developed controller
while crossing base speed

37. At No-Load : turn-on angle
Tu
rn
on
an
gle
(d
eg
)
Time (sec)

38. At No-Load : turn-off angle

39. Analysis of simulation results on No-load
Type of controller
at steady state rpm
0f 6560
PWM mode Single pulse mode
Turn-on
(degree)
Turn-off
(degree)
Current
ripple
(Amps)
Torque
ripple
(Nm)
Turn-on
(degree)
Turn-off
(degree)
Current ripple
(steady state)
(Amps)
Torque ripple
(steady state)
(Nm)
Basic 45 75 0 to 200
(200)
36 to 148
(112)
45 75 0 to 30.5 (30.5) 10 to 18
(8)
Developed 52.5 to
52.3
104 to 81 0 to 230
(230)
30 to 100
(70)
45.2 72 to 75 0 to 30
(30)
10 to 17.5
(7.5)

40. Analysis on No-load
• The developed controller operates with varied turn-on and turn-of
angles.
• The torque ripple is reduced in both PWM and single pulse mode
when the SRM is used with the developed controller.
• This is one aspect of the optimal performance of the SRM with the
developed controller.
• While operating at steady state in single pulse mode, the
maximum current/current ripple is less when the SRM is used with
the developed controller.
• The transition is smooth in terms of flux, current, torque or speed
when the motor shifts its operation from PWM mode to single
pulse mode.
• SRM delivers better performance when used with a controller
having varied turn-on and turn-off angles
• The turn-on and turn-off angles are varied at every instant in
synchronization with the formulae for optimal condition.

41. With heavy Load of 80 Nm

42. At 80 Nm Load: turn-on angle
Tu
rn
on
an
gle
(de
g)
Time (sec)
0 1 2 3 4 5 6 7 8
30
35
40
45
50
55

43. At 80 Nm Load: turn-off angle
Tu
rn
off
an
gle
(de
g)
Time (sec)
0 1 2 3 4 5 6 7 8
20
40
60
80
100
120
140
160

44. With speed dynamics (6560 to 8000 rpm)

45. With speed dynamics : Turn-on angle
Tu
rn
on
an
gle
(de
g)
Time (sec)
0 1 2 3 4 5 6
34
36
38
40
42
44
46
48
50
52
54

46. Tu
rn
off
an
gle
(de
g)
Time (sec)
1 2 3 4 5 6
60
70
80
90
100
110
With speed dynamics : Turn-off angle

47. With torque dynamics : 5 to 20 Nm

48. With torque dynamics : 5 to 20 Nm

49. Tu
rn
on
an
gle
(de
g)
Time (sec)
0 1 2 3 4 5 6 7 8
34
36
38
40
42
44
46
48
50
52
54
With torque dynamics : turn-on angle

50. With torque dynamics : turn-off angle
Tu
rn
off
an
gle
(de
g)
Time (sec)
1 2 3 4 5 6 7
60
70
80
90
100
110

51. Analysis of Simulation results on Load
Application PWM mode Single-pulse mode
Turn-on
angle (degree)
Turn-off
angle(degree)
Turn-on
angle (degree)
Turn-off
angle(degree)
80 Nm of load at 6560 rpm ref speed 52.5 to 52 128 to 72 43 to 32.2 64 to 78
Steep increase of load from 5 to 20
Nm at 6560 rpm ref speed
52.5 to 52.2 104 to74 41.2 to 40 to 40.2
to 35.8
66 to 68 to73
Steep increase of speed from 6560 to
8000 rpm at 5 Nm of load
52.5 to 52.2 104 to74 41.2 to 40 to 40.2
to 34.4 to 36
67 to 68 to 75 to
73

52. Analysis on Load
• The controller operates by varying the turn-on and turn-off angles at every
instant as per the requirement of that operating point.
• When the operation of the motor shifts from PWM mode to single pulse
mode, the turn-on angle is advanced to cater to the torque demand as the
overlapping of the phases is reduced.
• When there is a sudden increase of load from 5 Nm to 20 Nm or sudden
increase of speed from 5650 rpm to 8000 rpm the turn-on angle is advanced
and the turn-off angle is retarded to balance the new torque demand.
• The emphasis is made to show that to maintain optimal operating condition
the turn-on and turn-off angles vary to make the transition smooth between
the two optimal control modes
• It is proved now that the developed controller is able to control the SRM
over its entire speed and torque range.

53. Content
• Introduction
• Principle of operation
• Characteristics
• General control strategy
• Modes of operation
• Simulink model for proposed controller
• Simulation results and Analysis
• Conclusion
• References

54. CONCLUSION
• This project studies optimal control modes of the SRM by striking
a balance between maximum efficiency and minimum torque
ripple and thus calculates the optimum switch on angles and
switch off angles.
• The turn on and turn off angles are calculated through simple
formulas and implemented through Simulink building blocks.
• The optimum controller determines the turn-on and turn-off
angles at every instant and accordingly the converter switches are
fired to cater to the torque and speed demand of that instant.
• To validate the effectiveness of the controller, simulation is carried
out on a variety of load and speed combination and the
effectiveness is verified.

55. REFERENCES
[1] C.J. Van Duijn, “Development of methods, algorithms and soft wares for optimal design of
switched reluctance drives”
[2] F. Soares and P.J. Costa Branco, “Simulation of a 6/4 switched reluctance motor based on
Matlab/Simulink environment
[3] R Krishnan,” Switched Reluctance Motor Drives; Modeling, Simulation, Analysis, Design and
Applications”
[4] Han-Kyung Bae, “Control of Switched Reluctance Motors considering mutual inductance”
[5] Ardeshir Motomedi-Sedeh, “Speed control of switched reluctance motors”
[6] M. T. DiRenzo, "Switched Reluctance Motor Control – Basic Operation and Example Using the
TMS320F240, Texas Instruments Application Note," 2000.
[7] C. Mademlis and I. Kioskeridis, “Performance optimization in switched reluctance motor drives
with online commutation angle control,” IEEE
[8] C. Mademlis and I. Kioskeridis, “Maximum efficiency in Single Pulse Controlled switched
reluctance motor drives,” IEEE
[9] C. Mademlis and I. Kioskeridis, “Smooth Transition between Optimal Control Modes in switched
reluctance motoring,” IEEE
[10] Matlab R 2008a, Version 7.6

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