Proposal for an Active PV Array to Improve System Efficiency During Partial Shading

Owing to time-varying external environmental influences, undesirable string mismatches frequently occur in photovoltaic (PV) power generation systems, which will cause conventional PV systems to experience extremely severe power losses. Under partial shading conditions (PSCs) caused by passing clouds, neighboring buildings, and animal excrement, the characteristic curve of the PV string becomes complicated with multiple peaks, which increases the difficulty of determining the maximum power point (MPP) of the array. However, it is essential to ascertain the global maximum power point (GMPP) to extract the full power of each PV module. Therefore, we propose a new type of PV generation module constituting an active PV array (APV) system as well as its control strategy. It can ensure that the system continuously operates in the optimal state when the solar irradiation intensity drops drastically due to unanticipated environmental variables. Depending on the experiment of two PV arrays under identical conditions, the efficiency and reliability of the APV system are substantiated. Meanwhile, in the case where the external environmental conditions are deliberately changed, the experimental results fully illustrate the adaptability of the APV system to diverse harsh conditions.