An observer based rotor speed estimation technique for vector controlled induction machines
- 1. AN OBSERVER BASED ON-LINE ROTOR SPEED ESTIMATION TECHNIQUE FOR A VECTOR CONTROLLED INDUCTION MACHINE DEBASHIS CHATTERJEE, AGNIPROTIM SEN & TRIDIBESH NAG By
- 2. Introduction Problem at low speed due to limits of the frequency to voltage converter. Kalman filter is relatively complicated & require much powerful microprocessor. None of the equation completely satisfy the demands for sensor less vector control, including speed range & stability with motor parameter variation. Speed is obtained by the ripple generated in the stator voltages and currents.
- 3. AN OBSERVER BASED ON-LINE ROTOR SPEED ESTIMATION TECHNIQUE FOR A VECTOR CONTROLLED INDUCTION MACHINE What is an observer? Why it is used? What is the advantage of using an Observer in a induction machine system ?
- 4. AN OBSERVER BASED ON-LINE ROTOR SPEED ESTIMATION TECHNIQUE FOR A VECTOR CONTROLLED INDUCTION MACHINE What is On-line Rotor Speed Estimation Technique? Why it is Used? Different Types of Estimation Techniques
- 5. AN OBSERVER BASED ON-LINE ROTOR SPEED ESTIMATION TECHNIQUE FOR A VECTOR CONTROLLED INDUCTION MACHINE Magnitude and Power Factor angle ( φ ) can be controlled . Vector control method is widely used in controlling a induction machine. Though Vector Control is a complicated process but controlling is very accurate
- 6. Proposed Speed Estimation Technique Novel Rotor Speed Estimation method using MRAC to improve the performance of a sensor less controller . A New MRAC method is proposed in this paper that uses Stator Current as the State Variable for Estimating the Speed. The Stator Current is Represented as a function of the first degree for the error value of the Speed Estimation. Flux Observer Designed without any integrator and based on algebric equations involving the Measured & Filtered Signals.
- 7. What is MRAC (Model Reference Adaptive Control ? The idea behind Model Reference Adaptive Control is to create a closed loop controller with parameters that can be updated to change the response of the system to match a desired model.
- 8. Advantages of using MRAC method in the proposed model Easy to design. Improves the performance of sensor less Vector Controller at a Low Speed & zero speed. Hence Low speed and Zero speed Operation is possible. The method is self adjusting or self tuning.
- 9. Block Diagram of MRAC Technique
- 10. Algorithm of the Proposed Model NO YES NO YES
- 11. Literature Review part I Principal Equations: The rotor speed is given by, , Where, Is the Electromagnetic torque developed
- 12. Simulation Results Simulation was done in MATLAB/SIMULINK environment for the estimation of rotor speed The machine model parameters used for simulation is the same as the machine used for experiment. The noise which is seen for the estimated speed is due to digital noise considered in the estimator.
- 13. Validation of the Proposed Model HP 2 R s 11.2 Rated Speed 1440 R r 8.45 Phase 3 L ls & L lr 0.0886 Connection Delta L m 0.0890
- 14. Conclusion the stator current is used as the state variable for estimating the speed. In the proposed method, the stator current error is represented as a function of the first degree for the error value in the speed estimation. the proposed method uses no integrator for the speed estimation. The filtered stator current and the stator voltage are used as input variables for the estimator. But with this new method, the rotor time constant uncertainty still remains as a problem The robustness of the proposed method as regards parameter variations was compared with that of MRAC methods & the superiority of the proposed method was verified by simulation and experiments in a low speed as well as in the higher speed region.
- 15. Thank You