Online current-sensorless estimator for PV open circuit voltage and short circuit current

Abstract

The suggested paper presents a new method for the estimation of short circuit current (Isc) and open-circuit voltage (Voc) of the photovoltaic (PV) system. Moreover, a modified relation of reverse saturation current (Is) is used to prevent the wrong estimation of Isc and Voc values at any point of the P-V curve. In addition, a new current-sensorless method of PV current estimation is used to further reduce the cost of the proposed technique. The accuracy of the proposed method is checked by testing on three different PV panels such as Yingli 245C-30b, Sharp NT-180U1, and Risen SYP-110S. Moreover, the fractional short circuit current (FSSC) and fractional open-circuit voltage (FOCV) algorithms are also implemented using the proposed and conventional analytical method and their results are compared with each other. The proposed method is validated in the Matlab/Simulink and hardware experimentation. The results of the proposed method indicate the following advantages: (1) accurate prediction of the Isc and Voc values at any point of the P-V curve, (2) interruption free output power during the Isc and Voc measurement, (3) accurate sensorless estimation of PV current, 4) no overshoot and undershoot in the tracked power of PV module, and 5) significant improvement in tracking efficiency by 38.33% for the FSSC algorithm and 28.2% for the FOCV algorithm, compared to the conventional analytical method.