Loss minimization of two stage solar powered speed sensorless vector controlled induction motor drive for water pumping

This paper deals with a two stage solar photovoltaic (SPV) fed speed sensorless vector controlled induction motor drive (IMD) for water pumping system which is superior to conventional controlled motor as it is cheaper and reliable. One common practice is to estimate the flux from the terminal voltages and currents. The performance of the drive depends on the accuracy of the flux estimator. Usually the efficiency of the induction motor drive (IMD) is high around the rated load and deteriorates at partial loading. However, the efficiency can be enhanced by operating the motor at optimum flux by controlling the flux component of current. In this paper, a minimization technique is proposed to minimize the total losses to operate the drive at maximum efficiency. A modified perturb and observe (P&O) algorithm is used to track maximum power from SPV array. The smooth starting of the motor is attained by vector control of an induction motor. The system performance is simulated in MATLAB/Simulink environment and the results are compared with the conventional vector controlled IMD.