Upgradation of grid-connected water pumping system integrating multifunction PV inverter with reduced sensor

This article presents upgradation of existing grid-connected direct online-start water pumping system by integration of multifunction photovoltaic inverter. The multifunction photovoltaic inverter is operated using a voltage-oriented control such that it delivers the reactive power in addition to the real solar photovoltaic power to deal with practical issues like steady-state grid voltage variation and poor power factor on irrigation feeder. In the implemented voltage-oriented control, the adaptive modified second-order generalized integrator-based estimators are used to derive the grid voltage angle and the reactive component of the load current, which considerably reduces the requirement of the sensors. The methods to derive the different control system tuning parameters, i.e., second-order generalized integrator gains and proportional integral controller gains, are also described. A prototype is developed to investigate the performance of designed system. In the prototype, the control algorithm is implemented using a generic ARM Cortex-M4 microcontroller. Extensive experiments are performed, and the test results are presented to validate the system operations.