Improved non-symmetrical puzzle reconfiguration scheme for power loss reduction in photovoltaic systems under partial shading conditions

Abstract

The power output of photovoltaic arrays decreases because of mismatch losses when working under partial shading conditions, and various static reconfiguration techniques have been proposed to mitigate these losses. The non-symmetrical puzzle arrangement, as a static reconfiguration strategy proposed earlier, can use simple arithmetic operations to alter the physical location of photovoltaic panels without modifying the total-cross-tied based electrical connections. However, this arrangement has the disadvantage of poor shading effects and is unsuitable for large-size arrays. In this work, by introducing an odd–even configuration and redefining the shift distance, a systematic static reconfiguration method called the parity-column index is proposed to solve these problems. To verify the validity of the output characteristics, a 9 × 9 photovoltaic array output model was built using MATLAB/Simulink, and six shadow patterns were simulated. Furthermore, the proposed arrangements were compared with the total-cross-tied, odd–even, and non-symmetrical puzzle arrangements. The simulation results regarding the global maximum power point, power mismatch losses, percentage power loss, fill factor, and percentage power enhancement were analyzed separately, and the output characteristics of the above array reconfiguration methods were evaluated to verify the superiority of the proposed arrangement.