Power quality improvement in grid integrated solar water pumping system using Vienna converter

A new topology for solar water pumping (SWP) using a permanent magnet synchronous motor drive is proposed in this work. With the aim of overcoming the intermittency issues of solar photovoltaic (PV) generation, the utility grid is introduced in order to provide a reliable water pumping operation. The grid interface is facilitated using a Vienna rectifier, which enables the rated operation of the pump. The Vienna rectifier maintains the direct current (DC) link voltage, removes the grid current harmonics, and ensures unity power factor at the grid. A novel multi-resonant second-order generalized integrator frequency-locked loop (FLL)-based approach is proposed for extraction of fundamental positive sequence components from the grid voltages. The novelty of the proposed control approach lies in the elimination of dominant lower order harmonics from the sensed grid voltages through selective harmonic elimination. The FLL structure makes the control structure flexible to grid frequency change within small range. The optimum power point of solar PV array is extracted using an incremental conductance scheme. A sensorless field-oriented control is used for regulating the pump speed. The system ) performance is observed under different operating conditions on a laboratory developed prototype. Test results confirm the satisfactory performance and improved power quality indices fulfilling the IEEE-519 standard.