Battery Energy Storage for Seamless Transitions of Wind Generator in Standalone Microgrid

This paper presents a control scheme for a standalone microgrid having a nondispatchable fixed-pitch variable-speed wind generator (WG) and a battery energy storage (BES). The WG is directly interfaced at the point of common coupling (PCC) and the BES is interfaced at the PCC via a bidirectional dc-ac converter. The unique aspect of the control strategy is that the BES not only regulates the PCC voltage and frequency by active-reactive power compensations, but also ensures proper synchronization and disconnection of the WG during wind velocity variations. A simple control scheme, with only one interfacing converter and one voltage feedback loop, provides an uninterruptible electrical power supply to critical loads during various operating modes and enables seamless transition of the WG. Performance of the proposed system under all operating modes and transitions is tested through modeling and simulation in MATLAB/Simulink, and validated on laboratory test bench through implementation of the control algorithm on a DSP platform.