Energy management for PV–Battery DC microgrid with Processor-in-the-Loop validation of the Fuzzy Logic MPPT controller

Abstract

Photovoltaic (PV) systems face major challenges in voltage stability and power balance due to the intermittent nature of PV generation under varying climatic conditions, such as solar irradiance and temperature, which significantly constrain the ability to extract maximum power. This paper proposes an intelligent control and energy management strategy (EMS) for a stand-alone DC microgrid (DCMG) integrating a PV source and lithium-ion (Li-ion) battery storage. The system targets energy maximization, DC bus voltage (DBV) regulation, power balance, and battery protection by constraining the state of charge (SoC) within predefined safe limits to extend battery lifespan. The control strategy combines a Fuzzy Logic Controller (FLC) that regulates the duty cycle of a DC–DC converter for maximum power point tracking (MPPT) to maximize power extraction from the PV system under varying irradiance conditions, with a PID controller that manages a buck–boost converter to ensure DBV stability and power balance. The PV-Battery system is modeled and simulated using MATLAB/Simulink under diverse operating conditions. A comparative evaluation of the proposed FLC-MPPT and the widely used Perturb and Observe (P&O) method under varying solar irradiance conditions has been performed. To ensure realistic performance and robustness, the FLC-MPPT is validated in a real-time environment through Processor-in-the-Loop (PIL) implementation on an STM32F429 Discovery board. Results show that the proposed FLC-MPPT achieves 99.85% average efficiency with negligible oscillations, while the EMS provides DBV stability with a low overshoot bounded to ± 0.05 V, confirming fast response and robust stability under all tested conditions.