Tracking control of high-concentration photovoltaic systems for minimizing power losses

This paper presents three key factors that cause system mismatches and power losses in high-concentration photovoltaic (HCPV) systems. The first factor is the I-V mismatch within a module, similar to the manufacturing mismatches in conventional photovoltaic modules. The second factor is the misalignments amongst modules, and the third factor is the tracking control. Unlike in the conventional photovoltaic systems, the second and the third factors in HCPV systems introduce larger electro-opticalmismatches due to narrow acceptance angles. We have developed a model to address these three factors. It allows an accurate estimation of power losses in HCPV systems, which enabled us to propose configurations to reduce power losses without adding additional electrical components to the system. Simulation results show that the power harvest can be increased as much as 8.5% for a system using open-loop controls by simply increasing the number of strings at the time of calibration. Experimental test results are presented for validation. Copyright (C) 2012 John Wiley & Sons, Ltd.