Reduced DC sensor based grid-interactive operation of single-stage solar photovoltaic water pumping system

Abstract

ABSTRACT The grid-interactive operation of a single-stage solar photovoltaic water pumping system (SPVWPS) requires additional power electronic interface and a number of sensors. This paper realizes the grid-interactive operation of the single-stage SPVWPS with reduced sensor and without adding to the cost of the grid-interface converter. The single-phase grid is connected directly with the SPVWPS and the three-phase inverter is controlled as a single-phase grid-interactive inverter. The motor winding inductance is utilized as a current filter. This arrangement functions as a photovoltaic-static synchronous compensator (PV-STATCOM) with voltage-oriented current control by feeding the peak solar photovoltaic (SPV) power to the grid and supporting the reactive power to alleviate steady-state grid voltage variations. The modified adaptive second-order generalized integrator (SOGI) is utilized for effective grid-angle estimation under the presence of DC-bias in the input signal. The modified perturb and observed maximum power point tracking (MPPT) technique is implemented using grid-side quantities, which curtails the requirement of the SPV current sensor. Extensive experiments are performed on the developed prototype under the variable atmospheric and the variable grid voltage conditions. The presented grid-interactive SPVWPS is realized with single power electronics device and three sensors. The cost of power electronics interface is reduced in presented single-stage grid-interactive SPVWPS by 22% compared to two-stage grid-interactive SPVWPS. Abbreviations: FLL: Frequency Looked Loop; PFC: Power Factor Correction; FFT: Fast Fourier Transform; PV: Photovoltaic; SPVWPS: Solar Photovoltaic Water Pumping System; MPPT: Maximum Power Point Tracking; P & O: Perturb and Observe; SPV: Solar Photovoltaic; OSG: Orthogonal Signal Generator; PWM: Pulse Width Modulation; SOGI: Second-order Generalized Integrator; PEC: Power Electronic Converter; RMS: Root Mean Square; VSI: Voltage Source Inverter; PF: Power Factor; RMF: Rotating Magnetic Field; VSC: Voltage Source Converter; PI: Proportional Integral; SySPWM: Synchronous Sine Pulse Width Modulation