Empowered Virtual Synchronous Generator Based Control Scheme for Improved Transient Response and Reduced Nuisance Tripping in Stable Microgrids

Abstract

Multiloop voltage-controlled virtual synchronous generator (VSG) based control scheme is recently popular in forming stable microgrids. This scheme deploys traditional VSG (TVSG) control for power controllers in the outermost loop and proportional-integral synchronous reference frame-based voltage-current (PIVA) controllers in the inner loop (named TVSG-PIVA scheme). But, this scheme usually exhibits larger deviations and longer settling times in transient response under large active power demands. This poor transient response would further lead to unnecessary tripping which is referred to as nuisance tripping in the literature. This hampers the system’s stability even though there is no genuine fault. Thus, to address this problem, this paper proposes a modified VSG (MVSG) power controller based on adjusting the gain constant of the speed governor in the TVSG through an equalizing factor. From simulations, it is found that this MVSG supported by PIVA controllers (named MVSG-PIVA scheme) successfully avoided undesired trips under large active power demands, but, is susceptible to nuisance tripping under large reactive power demands. Thus, to effectively improve transient response and reduce the chances of nuisance trips under both large active/reactive power loads, this paper proposes a hybrid control scheme by deploying the MVSG power controller and internal model control-based VA controllers (named MVSG-IMCVA scheme). The efficacy of the proposed MVSG-IMCVA scheme is compared with the MVSG-PIVA scheme and conventional TVSG-PIVA scheme under different power factor loadings. From the results, it is proved that the proposed scheme improved the transient response and reduced unnecessary trips. Thus, the proposed modifications demonstrate the empowerment of the multiloop voltage-controlled VSG scheme, thereby ensuring system stability during dominant load changes.

Keywords

• Internal model control
• microgrids
• nuisance tripping
• transient response
• virtual inertia
• virtual synchronous generator