CHB-STATCOM Implemented with an Improved Virtual Synchronous Machine Controller with Adaptive Virtual Inertia

Control of virtual synchronous generators, also known as synchronverter control, is gaining prominence as an effective method for integrating renewable energy sources into utility grids or microgrids. This control technique emulates the response of a traditional synchronous generator, leading to enhanced system stability. This paper presents the design of a controller for a cascaded H-bridge based Static Synchronous Compensator (STATCOM), inspired by the concept of a virtual synchronous machine. The controller is developed based on the mathematical model of synchronous generators operating in the compensator mode. An additional operation, droop control mode is implemented in the operation of the STATCOM. This mode is introduced alongside the standard voltage regulation mode and the direct reactive power control mode. This enables the appropriate sharing of reactive power across parallel-operated STATCOM. This study presents a novel approach for adaptive virtual inertia control by utilising an enhanced bang-bang control method.