1. S peed E stimation of I nduction M otors with R otor S lot H armonics 5 th International Scientific Conference on Energy and Climate Change Alfred PJETRI Ymer LUGA Myrteza BRANESHI Astrit BARDHI 11-12 October 2012, Athens Greece

2. Rotor Speed Monitoring in Induction Motors  Conventional Techniques (Mechanical Speed Sensor )  Mathematical Model of IM (MRAS)  Rotor Slot Harmonics SENSORLESS

3. C onventional T echniques  D.C. Tachogenerators  A.C. Tachogenerators  Encoders  Resolvers

4. Mechanical Sensor Disadvantages  Increase the cost of control system  Gives errors because of mounting  Vibration  Ingress of contaminant  Reduces the system reliability

5. S ensorlees T echniques  Mathematical Model of IM (MRAS)  Rotor Slot Harmonics

6. M athematical M odel S ensorlees T echniques D isadvantages  Nonlinearity of Magnetic Circuit  Rotor and Stator Resistance Variation with Temperature

7. A ir G ap F lux of I nduction M achines

10. E.m.f. induced in stator winding.

11. A nalysis of R otor S lot H armonics.

13. Signal Measurement for Rotor Slot Harmonics

14. Fundamental frequency of voltage signal Induction Motor Rotor Speed in RPM

15. Eksperimental Setup Stand

16. Experimental Results Measured 1492 rpm Estimated 1490 rpm

17. Measured 1469 rpm Estimated 1466 rpm Experimental Results

18. Measured 1430 rpm Estimated 1431 rpm Experimental Results

19. C OMPARISON OF MEASURED AND ESTIMATED SPEED Nr. f s [Hz] f 1 [Hz] n estimated [rpm] n measured [rpm] Error [%] 1119250149014920.134 2118550148014770.203 3117450146614690.203 4116850145814540.275 51162501450 0 6115550144114420.069 7114750143114300.070 81137501418 0 9113150141014080.142

20. P [kW] n [rpm] U [V] I [A] cos  f 1 [HZ] 314303806.90.8250 INDUCTION MOTOR RATED DATA Number of rotor slots Zr=46

21. C ONCLUSIONS  Does not need mechanical sensor  Maintenance free  It is not affected by environment  Do not depend of motor parameters  Simple and robust method

22. THANK YOU