A unified single-controller approach of an MPPT and droop control for solar PVs in DC microgrid under unequal and partial shading conditions

In the context of DC microgrids, there has been a growing trend towards integrating solar photovoltaic (PV) sources to generate distribution in remote locations. In order to ensure the effective operation of PV sources, it is necessary to implement an efficient controller that can manage their intermittent nature and uncontrollable penetration in various conditions. This work aims to develop an effective maximum power point tracking (MPPT) and droop-coordinated control method for PVs under unequal shading conditions in a DC microgrid, allowing maximum power extraction and load sharing using a single controller. Further, it will operate with the same controller in droop mode (voltage control method) to balance the power during excess power generation of PVs and enable the parallel operation of multiple PV sources. By sensing DC bus voltage, the single controller works on both MPPT and droop mode to eliminate additional switches as in conventional methods. Most importantly, the proposed controller is shown to outperform during the partial shading of PVs. The proposed controller with the converter is designed and modelled with a DC microgrid in the MATLAB/Simulation platform. Power flow management and maximum power extraction performance is thoroughly tested and evaluated under diverse operating conditions. Thereby, the total efficiency of the system is increased. It reduces the complexity of the controller and low computational burden for real-time deployment. Furthermore, the practical viability of the proposed control method is validated by developing a prototype hardware setup in the laboratory. Comparing the suggested control method to state-of-the-art methodologies and benchmarks, the experimental findings show that it is feasible. As a result, it is regarded as a potential option for both MPPT and droop control during unequal and partial shading conditions for accurate power-sharing with voltage stability.