A Fixed Zone Perturb and Observe MPPT Technique for a Standalone Distributed PV System

This article proposes a fixed zone perturb and observe (FZPO) technique to achieve improved steady-state efficiency and a fast and drift-free maximum power point tracking (MPPT) for photovoltaic (PV) systems without any additional sensors. In this technique, the PV array's power-voltage (P-V) curves are divided into multiple zones with unique zone boundary voltages for different irradiance conditions. This technique employs a combination of adaptive and fixed step sizes to improve the performance, where the adaptive step size is calculated from simple mathematical equations, resulting in a reduced computational burden. Besides, natural drift-free tracking is achieved without any additional sampling or computation, overcoming existing techniques' limitations. The FZPO technique requires a PV panel's information only at the initial design stage but not during real-time tracking, making the implementation possible using only low-cost processors. This article presents the implementation and design of the proposed controller. The FZPO technique's performance is validated through a comprehensive set of hardware experiments on a buck-boost full-bridge (BBFB) converter under various irradiance conditions per the EN50530 standard. For a step change in irradiance, the FZPO technique is experimentally verified to be 42% and 20% more efficient than the conventional and VSS techniques, respectively. During the irradiance varying conditions using the FZPO technique, the peak power loss is one-sixth compared to the conventional and VSS techniques. Practical field-related considerations, such as PV panel temperature effects, are further investigated through experiments.