Seamless transitions of distributed generators in standalone microgrid for unintterupted power supply

This paper presents a control scheme for a standalone microgrid having a variable-speed wind-generator (W G) and a diesel-generator (DSG) both directly interfaced at a point of common coupling (PCC), and a battery energy storage (BES) interfaced at the PCC via a bidirectional DC-AC converter. The BES not only regulates the PCC voltage and frequency during wind and/or load power variations, but also ensures proper synchronization and disconnection of the WG and DSG based on the availability of the energy sources. Thereby, the BES enables seamless transitions of different components between various operating modes, while providing uninterrupted power supply to critical load. The requirement of only one interfacing converter for interactions among the WG, DSG and BES is the unique aspect of the proposed scheme. Performance under various operating modes and transitions is tested through modelling and implementation of the control algorithm in MATLAB/Simulink to demonstrate applicability of the proposed scheme.