Seamless Operation of an SRG Based WEGS and a Bidirectional Converter Interfaced BES Microgrid Under Polluted Grid Conditions

Switched reluctance generators (SRGs) are excellent candidates for wind energy generation systems (WEGS), as they present higher efficiency, simple construction, low maintenance, neither magnets nor windings on rotor, wide-speed operation, and fault-tolerant capability. The machine, on other hand, presents challenges owing to its highly nonlinear behavior. Nonetheless, high dynamic performance SRG-based WEGS can be attained with the application of appropriate control techniques. A microgrid (MG) consisting of a WEGS using SRG and a bidirectional buck-boost converter (BDC) interfaced battery energy storage (BES) is presented in this work. DC power sources are integrated at the point of common coupling (PCC) using a voltage source converter (VSC), where the utility grid and AC loads are connected. VSC is controlled using a mixed second and third-order generalized integrator (MSTOGI) filter to obtain the load compensation by extracting fundamental active component from nonlinear load currents. Moreover, the MSTOGI filter estimates fundamental frequency positive sequence components (FFPSCs) of the grid voltages to generate the reference grid currents. Therefore, even at distorted/unbalanced grid conditions, the grid currents follow sinusoidal, balanced, and unity power factor (UPF) with the FFPSCs. Hence, MG follows the IEEE-519 standard recommended limits of interconnection. MG operates in grid-connected mode (GCM) or standalone mode (SAM), according to the availability of the utility grid. In a grid failure, MG automatically transfers its operating mode from GCM to SAM, providing uninterrupted power to local loads while complying with the IEEE-1547 standard.