Reduced-Sensor-Based PV Array-Fed Direct Torque Control Induction Motor Drive for Water Pumping

This paper aims at the design, control, and implementation of a solar photovoltaic (PV) array-fed speed sensorless direct torque control of an induction motor drive (IMD) for water pumping in a standalone as well as battery-connected hybrid mode. This stator flux estimated by the proposed flux observer is used for speed estimation. A dc-link current sensor is used to reconstruct the motor phase currents by modified active voltage vector. One voltage sensor for dc-link voltage sensing and only one current sensor for dc-link current sensing are used in this system for standalone operation of the system. All other required quantities are estimated through these two sensed signals. The IMD is energized by a PV array, which is operated at maximum power point (MPP). A perturb and observe control algorithm with additional flow rate controller is proposed for MPP, which tracks MPP throughout the operating range and provides the facility to control the flow rate. The suitability of the system is judged through simulated results in MATLAB/Simulink as well as test results obtained on a prototype developed in the laboratory.