Isolated Operation of Variable Speed PMSG with Battery Storage System for WECS

This paper presents a stand-alone wave energy conversion system (WECS) with battery storage. The system consists of a wave energy extraction device namely oscillating water column (OWC) model, Wells turbine, permanent magnet synchronous generator (PMSG), diode rectifier, buck converter and an energy storage system connected to an isolated load. The voltage generated by PMSG varies in magnitude and frequency in accordance with speed with which it is driven by the turbine. Speed of the turbine depends on the wave data input to the OWC model. The ac voltage generated is rectified using an uncontrolled diode rectifier. A buck converter is used to maintain constant dc link voltage and to interface an efficient battery energy storage system (BESS). The main purpose of BESS is to maintain power balance by absorbing power during peak generation and to release it during lower power generation. The proposed strategy is realized and simulated in MATLAB/Simulink environment. The analysis of simulated results demonstrates the smooth operation of proposed system in an isolated network.