EXPERT SYSTEMS AND SOLUTIONS Project Center For Research in Power Electronics and Power Systems IEEE 2010 , IEEE 2011 BASED PROJECTS FOR FINAL YEAR STUDENTS OF B.E Email: expertsyssol@gmail.com, Cell: +919952749533, +918608603634 www.researchprojects.info OMR, CHENNAI IEEE based Projects For Final year students of B.E in EEE, ECE, EIE,CSE M.E (Power Systems) M.E (Applied Electronics) M.E (Power Electronics) Ph.D Electrical and Electronics. Training Students can assemble their hardware in our Research labs. Experts will be guiding the projects. EXPERT GUIDANCE IN POWER SYSTEMS POWER ELECTRONICS We provide guidance and codes for the for the following power systems areas. 1. Deregulated Systems, 2. Wind power Generation and Grid connection 3. Unit commitment 4. Economic Dispatch using AI methods 5. Voltage stability 6. FLC Control 7. Transformer Fault Identifications 8. SCADA - Power system Automation we provide guidance and codes for the for the following power Electronics areas. 1. Three phase inverter and converters 2. Buck Boost Converter 3. Matrix Converter 4. Inverter and converter topologies 5. Fuzzy based control of Electric Drives. 6. Optimal design of Electrical Machines 7. BLDC and SR motor Drives

1. EXPERT SYSTEMS AND SOLUTIONS
Email: expertsyssol@gmail.com
expertsyssol@yahoo.com
Cell: 9952749533
www.researchprojects.info
PAIYANOOR, OMR, CHENNAI
Call For Research Projects Final
year students of B.E in EEE, ECE,
EI, M.E (Power Systems), M.E
(Applied Electronics), M.E (Power
Electronics)
Ph.D Electrical and Electronics.
Students can assemble their hardware in our
Research labs. Experts will be guiding the
projects.
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 1

2. Tutorial 2
Sensorless Motor Drives
Ralph M. Kennel
Elektrical Machines and Drives
Wuppertal University
Page 2

3. Reasons for Industrial Applications
of Drives with Encoderless Control:
• Cost
• Reliability
• Robustness
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 3

4. Industrial Drives with Sensorless Control
since several years / decades sensorless control is investigated
and published on conferences and magazines
- acceptance in industry, however, is rather low
Why ?
new ideas and concepts are interesting for industry,
only if they do not result in higher cost or higher effort!!!
What does that mean
for industrial drives with sensorless control ?
 no additional or more powerful processors / controllers
 no additional hardware or additional sensors (e. g. voltage sensors)
 no increased installation effort with respect to parameter adjustments
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 4

5. Sensorless (Encoderless) Motor Drives
introduction
• fundamental model methods
• high frequency injection methods
sensorless control of electrical machines
• machine response on high frequency injection voltages
• tracking of magnetic saliencies / anisotropies
practical results
• experiences with industrial drives
conclusions
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 5

6. Categories of Machine Models for „Sensorless“ Control
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 6

7. fundamental model high frequency injection
• simple realisation
• does not work at frequency 0
• parameter dependencies
current injection voltage injection
• measuring voltage is high enough
• additional voltage sensors
Basic Principles current response
transient current response stationary
• no additional hardware • standard microcontroller sufficient
of Encoderless• very small measuring current
• very short measuring time Control
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 7

8. Fundamental Model of an Induction Machine
stator rotor
when knowing voltage uS mechanics
as well as current iS
it should be possible
calculate speed ω
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 8

9. Calculation of Speed by Fundamental Model
is not Practicable for Very Low Speeds
... because
• the voltage signal becomes very small
• errors between real voltage and values used for calculation
cannot be avoided and become more significant
• DC components of these errors
let the integrators for flux calculation drift away
 the calculated speed gets more and more incorrect
is an encoder/resolver the only feasable solution ??
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page 9

10. Signal Injection Method
according to J. Holtz, H.Pan, etc.
• this is basically a current injection method
 voltage sensors are necessary !!!
• it is possible to use current derivatives
instead of motor voltages
 measuring current derivatives, however,
by standard current transducers is not really possible
• but, industrial current transducers
have a current derivative available internally
can this be made available for customers ???
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

11. INFORM method
according to M. Schroedl
(Technical University of Vienna, Austria)
• this is basically a transient voltage injection method
 currents have to be sensed at specific times !!!
• when using standard current transducers
 these cannot be synchronized with PWM
 the hardware of a standard industrial drive
has to be changed
nevertheless this method comes close to industrial needs !
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

12. Stationary Signal Injection Methods
according to R. Lorenz, S.-K. Sul, R. Kennel, etc.
• the basic idea is
to use the electrical machine itself as a resolver !!!
• a resolver is nothing else but an electrical machine
 can we operate the motor itself like a resolver ?
• if the machine itself is a resolver (encoder)
 is that really an „encoderless“ control ???
good idea – but does it work ???

Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

13. Resolver
injection of a sensing of a two-dimensional
stationary (sinusoidal) stationary (sinusoidal)
high frequency signal signal response
Tamagawa
S2
u1(γ) π 2π
R1 0
γ
Stator Rotor
Stator
ue uR
u2
R2 S4
u2(γ)
Stator π 2π
0
u1 γ
S1 S3
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

14. Stationary Signal Injection Methods
according to R. Lorenz, S.-K. Sul, R. Kennel, etc.
• the basic idea is
to use the electrical machine itself as a resolver !!!
• a resolver is nothing else but an electrical machine
 can we operate the motor itself like a resolver ?
• if the machine itself is a resolver (encoder)
 is that really an „encoderless“ control ???
now we do the same with an electrical AC machine

Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

15. Fundamental Frequency Excitation
(in α-β coordinates)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

16. High Frequency Excitation
(in α-β coordinates)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

17. Machine Model for High Frequency Signals
d ic(F) (F) lsσ d 0 
uc(F) = rs ic(F) + lsσ (F) + jωa lsσ (F) ic(F) lsσ =
dt  0 lsσ q 

Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

18. High Frequency Behaviour of the Machine Model
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

19. injection of high frequency voltages
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

20. injection of high frequency voltages
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

21. injection of high frequency voltages
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

22. injection of high frequency voltages
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

23. Injection of High Frequency Rotating Phasors
rotating voltage phasor uc elliptic current response ic
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

24. Position Information of Salient Rotors
in High Frequency Rotating Phasors
• machine responds
on a rotating voltage phasor
with an elliptic current response
• ellipse is correlated
with the geometric anisotropy
of the rotor
• rotor position information
is included elliptic current response ic (rotating)
in the high frequency current
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

25. Saturation Anisotropy
of a Permanent Magnet Synchronous Machine
rotor flux saturation of a
permanent magnet synchronous machine
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

26. Position Information of non-salient rotors
in High Frequency Rotating Phasors
• machine responds
on a rotating voltage phasor
with an elliptic current response
• ellipse is correlated
with the saturation anisotropy
• rotor position information
is included
in the high frequency current elliptic current response ic (rotating)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

27. Injection of High Frequency
Alternating (Pulsating) Voltage Phasors
advantage :
composing an alternating (pulsating) voltage phasor no rotational (HF) field
by two phasors rotating in opposite direction  no additional torque
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

28. High Frequency Current Response
of a Synchronous Machine
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

29. Current Response
of a Misoriented System
voltage and current
show different orientation !!
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

30. Current Response
under a Misorientation of 90°
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

31. Tracking Scheme for Magnetic Anisotropies
ˆ
icd (F) = K ⋅ sin ( ω c t ) lcq
ˆ
( )
icq (F) = − K ⋅ sin ( ω c t ) lcq − lcd ∆ δˆa
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

32. Tracking Scheme for Magnetic Anisotropies
Tracking the estimated angle of the rotor flux by controlling icq to 0
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

33. tracking control of injection voltage
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

34. tracking control of injection voltage
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

35. tracking control of injection voltage
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

36. tracking control of injection voltage
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

37. ) e
ns
tracking control of injection voltage r(
res
po
to
/v ec
s or
fundamental voltage phasor/vector
ph
a
t n
rre y
fundamental current phasor/vector
cu
e nc
qu
h fre
hig
injecte
d hi gh
freque
voltag
nc y
e pha
sor/ve
ctor
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

38. tracking control of injection voltage
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

39. Encoderless Control Structure
step response of the PLL;
PLL is locked after ca. 10 -15 ms
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

40. tracking control of injection voltage
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

41. tracking control of injection voltage
fundamental voltage phasor/vector
fundamental current phasor/vector
injected high frequency
voltage phasor/vector
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

42. tracking control of injection voltage
fundamental voltage phasor/vector
cy
fundamental currentnphasor/vector
freque ctor
e d hi gh pha sor/ve
inject v oltage
high frequency
current phasor/vector (response)
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

43. control structure
of an encoderless control
with alternating high frequency
signal injection
the estimated angle can be used
for field orientation as well as for
speed or position control
of synchronous machines
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

44. north and south pole
can be distinguished
a) theoretisch b) experimentell
trajectory of stator admittance
(SMPMSM, carrier frequency fc = 0.5 kHz)
Stator Admittance in Complex Plane
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

45. Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

46. Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

47. Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

48. Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

49. Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

50. Tracking Control
tracking of estimated rotor flux angle by adjusting/controlling icq to zero
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

51. north and south pole
can be distinguished
a) theoretisch b) experimentell
trajectory of stator admittance
(SMPMSM, carrier frequency fc = 0.5 kHz)
Stator Admittance in Complex Plane
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

52. the concept of encoderless control as presented here
works similar to radio broadcasting :
the information of rotor position
is modulated by a high frequency signal
the information is demodulated / extracted
from motor currents
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

53. Modulation of Carrier Signals by Electrcial Machines
• Synchronous Machines
works fine !!
• Induction Machines
further research to be done !!
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

54. Combination of
Field Oriented Control
and Encoderless Detection
of Rotor Position
• the estimated angle can be used
for field orientation as well as
for speed and/or position control
of synchronous machines
• high frequency test signals are superposed to
the fundamental stator voltage(s)
• drive control structure remains as before
• no additional sensors required
• the scheme is parameter independant
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

55. Sprungantwort der Drehzahlregelung
Drive with Speed Control
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

56. Sprungantwort der Lageregelung
Step Response of Encoderless Position Control
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

57. Results
• the tracking control scheme presented here
synchronizes on the saturation anisotropy
of a synchronous machine.
• the tracking control scheme
is not depending on any machine parameter.
• the size of additional software for the tracking control
is comparable to the software of a rotor model
for the field oriented control of an induction machine.
• the high frequency current signal can be measured
together with the fundamental current
by the standard current transducers
of a standard drive inverter.
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

58. Practical Experience with an Industrial Servo Drive
Implementation of a sensorless control
into a servo drive of
• training of a development engineer
2 x 1 week in our laboratory
• programming of additional software
in manufacturer‘s factory
• delivery of prototype
after ca. 3 months
• presentation on Hanover Fair
in April 2006
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page

59. Conclusion
• The proposed estimation method is simple
and therefore suitable for usual microcontrollers
 no additional or more powerful processors / controllers
• The sensorless control scheme presented here
does not need additional voltage measurement devices
- neither on the machine/motor side nor on the line side
 no additional hardware or additional sensors (e. g. voltage sensors)
• The phase tracking method
is very robust to variations of the system parameters
 no increased installation effort with respect to parameter adjustments
Prof. Dr. -Ing. Ralph M. Kennel Wuppertal University
Page