Wind-BES Based Microgrid with Seamless Synchronization

Abstract

The non conventional energy generation is a cleaner alternative of greener AC microgrid. This paper presents the performance enhancement of a non conventional energy based microgrid for the seamless grid synchronization. A robust control strategy is used for wind energy conversion system (WECS) and battery energy storage (BES) based nonconventional energy system (NCES) with seamless changeover proficiency from an islanded (IL) mode to the grid-connected (GC) mode and grid reconnected (GR) mode. The NCES has a capability to feed the load both in GC and IL modes and it operates smoothly during mode shifting from IL to GC and GC to IL. The unknown disturbances and ambiguity of NCES in GC mode are taken care by multilayer harmonic decoupling network based quadrature fourth order complex filter (MHDN-QFOCF). The issues like fluctuation in power, DC offset, voltage unbalance, swell/sag produced by WECS, are successfully taken care by MHDN- QFOCF. . With the help of this algorithm, the l quadrature sinusoidal fundamental component (Q-SFC) is extracted. It improves overall system capability of power flow. To control the NCES in an IL mode, the proportional plus resonant (P+R) based control algorithm is used. A dual fourth order complex filter (DFOCF) is combining to phase locked loop (PLL) and develops DFOCF-PLL for precise and smooth synchronization and resynchronization of grid. DFOCF-PLL improves system performance without affecting the stability. During frequency variation, it effectively follows the voltages of the grid and the load and it is adjustable to different conditions of grid. Moreover, total harmonic distortions (THDs) of the load and grid parameters are in the limits of the IEEE-519 standard.