A comprehensive analysis of control strategies for enhancing regulation in standalone photovoltaic systems

Abstract

This article extensively analyses PI, Type-2, and Type-3 controllers in interfacing converters, specifically focusing on boost and interleaved-boost converters. The primary objective is to enhance regulation within a standalone microgrid system integrated with photovoltaic (PV) sources. The analysis encompasses various aspects of regulation, including line and load regulation, reference tracking, and parametric sensitivity analysis. The initial phase of the study involves examining interfacing converters, specifically the boost and interleaved-boost converters, using small-signal modelling in the continuous conduction mode (CCM). Subsequently, we propose and implement PI, Type-2, and Type-3 controllers for the closed-loop operation of these converters to achieve improved dynamic efficiency and reliability. The implemented control strategy integrates maximum power point tracking (MPPT) with these controllers (PI, Type-2, Type-3) and compares boost and interleaved-boost converters comprehensively. This comparison is supported by theoretical, numerical, and graphical analyses of various transient parameters such as rise time, settling time, and maximum overshoot. The results of our study demonstrate that the interleaved-boost converter (IBC) coupled with a Type-3 controller exhibits the most favourable transient performance across all aspects of regulation, including line and load regulation, reference tracking, and parametric sensitivity analysis. To validate the proposed methodology, we conducted experimental work with an input voltage of 10 V, using the parameters of the Exide 225-watt polycrystalline solar panel as a reference.