Current Collector Optimizer Topology with Reconfiguration Algorithm to Harvest Optimal Power from Nonuniform Aged PV Arrays

摘要

Centralized inverter architecture is the most widely used technology for large-scale PV power plants owing to its simplicity, low cost per unit power, and high energy conversion efficiency under ideal conditions. Nevertheless, the energy harvest from the traditional centralized inverter with series-parallel (SP) topology is drastically decreased because of the uneven distribution of aging between PV modules. Nonuniform aging phenomenon is a common problem of outdated PV power plants since they typically serve for a long time under harsh outdoor operating conditions. Thereby, it is essential to advance centralized inverter technology for nonuniform aged PV arrays to prolong their service time and increase their efficiency. This paper presents a current collector optimizer (CCO) topology with a reconfiguration approach to extract optimal power from nonuniform aged PV arrays. A comparative study is conducted with (8×8) SP topology to confirm the efficacy of the proposed topology. Using the CCO topology, the performance of the nonuniform aged PV array is improved with smooth characteristic curves and a singular maximum power point (MPP). Thus, the CCO topology is not influenced by misleading power losses and requires only offline reconfiguration of aged modules to acquire optimal power. Eventually, a simple reconfiguration algorithm is proposed to extract optimal power from erratic aged modules for large-scale CCO topology applications.