Modelling analysis and simulation of motor parameter variation in vector controlled electrical drives

The aim of this paper is to compare the influence of parameter uncertainties on the performance of two vector-oriented control schemes of an induction motor drive. In the first, the field-oriented control method is used to control the speed of the induction motor. In this system, the spatial vector of the stator current is transformed into a i _1q component which creates the torque, and into a i_1d component which creates the flux. If the d-axis component of the stator current is of a constant value, the motor drives with a constant flux and the torque can be altered rapidly by means of the q-axis component of the stator current i_1q. Two components U_1d ,U_1q of stator voltages in the d-q coordinate system, which must be applied to the stator d-q equivalent windings, are generated by two PI regulators controlling the two components-flux-generating and torque generating stator current. In the second scheme, the stator flux-oriented control method is used to control the torque of the induction motor. By using instantaneous voltage space vectors with selection of optimum inverter switching modes employing the vector modulation technique, the direct control of torque and stator flux is achieved