Analysis and DSP Implementation of Sensorless Speed Control of Induction Motor Using Model Reference Adaptive Controller and Luenberger Observer

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Addis Ababa University


In this thesis, a model reference adaptive system (MRAS) and Luenberger observer (LO) based speed estimator is designed to control the speed of induction motor with no mechanical speed sensor. The proposed method involves two models, reference and adaptive model for the estimation of rotor fluxes and speed. The identified rotor fluxes from the Luenberger observer system (reference system) are used for the identification of rotor angular speed in the adaptive model. Induction motor is highly sensitive to motor parameter variation at low and zero speed. To overcome this parameter mismatch stability analysis is carried out. So that feasible range of operation is well known. Model reference adaptive system (MRAS) and Luenberger observer (LO) based sensorless speed estimator was analyzed in terms of different reference input tracking capability, torque response quickness, low speed behavior, response of drive with speed reversal, sensitivity to motor parameter variation. The system gives good performance at low speed and both at no load and loaded condition. From the simulation results, the rotor speed is estimated with a steady state error of 0.4% and good transient response with rise time of 0.023 second and settling time of 0.05 second. Rotor flux is estimated with 0.024 second rise time, 0.2% steady state error and settling time of 0.05 second. Stator flux is estimated with 0.02 second rise time, 2% second steady state error, settling time of 0.03 second and 17% of maximum overshoot. The proposed sensorless vector control operation is verified by simulation on MATLAB/Simulink and closed loop demonstration using Texas Instruments HVMTRPFCKIT with TMS320 F28035 DSP piccolo control card on 180w induction motor. From the demonstration work the rotor speed of the motor with maximum steady state error of 0.1800537% has been achieved under no load condition.



Vector control, Direct field oriented control, MRAS, LO, Sensor-less, Low speed, Piccolo TM TMS320F28035 Control Card