Decentralized Primary Control of PV-Battery System Integrated With DC Microgrid in Off-Grid Mode

Abstract

DC networks have created a lot of interest in distributed energy resources (DERs) applications. In the literature, several ways for managing the operation of such systems have been offered. Droop control is one of the control approaches that, in the majority being used for managing multiple DERs. However, there are significant disadvantages in conventional droop control in a dc MG, including poor regulation of the common dc-link voltage and use priorities of different sources. This paper presents a parallel operation ofPV and battery systems feeding to a critical and non-critical load. A combination of droop and dc bus signaling (DBS) control principles is used to handle the entire procedure. In the proposed control, multiple operating bands like normal operation (NO) band, safety operation (SO) band, and critical operation (CO) band, as well as different droop characteristics for various dc sources and load, are taken. The energy storage (ES) incorporates the state of charge (SoC) into the droop characteristic at the primary control level, creating a two-variable droop surface. Simulation results for a dc MG network containing a PV system, a lead-acid battery, and a load coupled to a dc bus are used to validate the suggested control technique.