Battery Supported Solar Water Pumping System With Adaptive Feed-Forward Current Estimation

This work presents an adaptive feed-forward current fed battery-supported solar water pumping system using a synchronous reluctance motor (SYRM). It incorporates the impact of cross saturation in real time with the position sensorless vector control technique of SYRM. Moreover, a continuous estimation of direct axis inductance ( L_d ) is incorporated to ensure saturation in SYRM. The burden of the DC link voltage PI controller is relieved by the feed-forward term of an adaptive battery current, which is calculated from the photovoltaic (PV) array power, estimated output power and the estimated motor efficiency. A DC-DC boost converter is used for maximum power point tracking (MPPT) of the solar photovoltaic array. A voltage source inverter is employed to control the SYRM-pump drive, and to charge/discharge the battery, a bidirectional DC-DC converter is used. The system provides a cost-effective solution for an uninterruptable and rated discharge of the water supply. The solar PV array behaves as a primary energy source, whereas battery is used as a backup source and is charged by PV array when pump operation is suspended or operating at a lower rating. The satisfactory performance of developed system is verified through experimental results taken on the developed laboratory prototype.