Utility Grid Interfaced Solar WPS Using PMSM Drive With Improved Power Quality Performance for Operation Under Abnormal Grid Conditions

Owing to the intermittency issue associated with renewable energy sources, a solar photovoltaic (PV) array fed grid interfaced encoder-less permanent magnet synchronous motor (PMSM) based solar water pumping (SWP) system is presented in this paper. The grid integration enables a continuous water flow regardless of available solar insolation. However, it has been observed that the grids in developing and underdeveloped countries are mostly weak. Moreover, as SWP systems are typically established at remote locations, which are generally the grid radial ends, therefore, prone to various grid abnormalities. Such abnormalities affect the SWP system performance. Therefore, a hybrid multi-resonant generalized integrator-frequency locked loop (HMRGI-FLL) control structure is presented in this paper to deal with the abnormalities in grid voltage and makes the SWP system operational even under weak grid condition. The proposed structure not only rejects the dc-offset but it also eliminates the dominant lower order harmonic with its selective harmonic elimination capability. A boost converter is used on the grid side to facilitate the power transfer from the grid. In condition of grid failure, the output water flow is regulated in accordance with available solar insolation. The speed of the PMSM is regulated using sensor-less vector control. Performance of the proposed system is experimentally validated using a laboratory prototype under varying solar insolation, during grid failure, during voltage sag, voltage swell, and distorted grid voltage conditions.