MODELLING ANALYSIS & DESIGN OF DSP BASED NOVEL SPEED SENSORLESS VECTOR CONTROLLER FOR INDUCTION MOTOR DRIVE

Unscented Kalman Filter (UKF), which isan updated version of EKF, is proposed as a state estimator for speedsensorless field oriented control of induction motors. UKF state update computations, different from EKF, are derivative free and they do not involve costly calculation of Jacobian matrices. Moreover, variance of each state is not assumed Gaussian, therefore a more realistic approach is provided by UKF.In order to examine the rotor speed (state V) estimation performance of UK Fexperimentally under varying speed conditions, a trapezoidal speed reference command is embedded into the DSP code. EKF rotor speed estimation successfully tracks the trapezoidal path. It has been observed that the estimated states are quite close to the measured ones. The magnitude of the rotor flux justifies that the estimated dq components of the rotor flux are estimated accurately. A number of simulations were carried out to verify the performance of the speed estimation with UKF. These simulated results are confirmed with the experimental results. While obtaining the experimental results, the real time stator voltages and currents are processed in Matlab with the associated EKF and UKF programs.