Grid connected solar water-pumping system based on sensorless PMSM drive

Abstract

This thesis deals with an effective power transfer scheme between the solar photovoltaic (PV) array and single or three-phase grid, feeding permanent-magnet synchronous motor (PMSM) drive applied to a water-pumping system (WPS). This system enables a consumer to operate the water pump at its full capacity for 24 hours regardless of the climatic condition and to feed a single or three-phase utility grid when water pumping is not required. The full utilization of a PV array and motor pump is made possible, in addition to enhancing the reliability of the pumping system. A voltage source converter (VSC) with a unit vector template generation technique accomplishes a bidirectional power flow control between the grid and the dc bus of the voltage source inverter (VSI), which feeds a (PMSM) motor. A sensorless MRAS-based estimator with field-oriented control (FOC) is used to drive the PMSM coupled to the water pump. Under variable isolation, an intermediate stage boost converter is used for extracting optimum power from a solar PV array. The duty ratio for the maximum power point (MPP) operation is generated using Perturb and Observe (P&O) technique. The utility single-phase grid in conjunction with a PV array fed PMSM coupled water pump ensures bidirectional power flow control based on the unit vector template (UVT) technique, however, in three-phase utility grid a voltage-oriented control (VOC) is used to manage the power flow in the system. The Fast Fourier Transform (FFT) analysis is done on the grid current to check that the criteria imposed by the IEEE-519 standard are met, and total harmonic distortion is within the allowed range.