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

TLDR: 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, and the implementation and design of the proposed controller are presented.

Abstract: This paper proposes a fixed zone perturb & observe (FZPO) technique to achieve an improved steady-state efficiency as well as 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 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 paper 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 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.