A Novel Energy-Type SVG with Grid Forming Control for Grid Voltage and Inertial Support

Large scale renewable power plants (e.g., wind farms) are typically equipped with the cascaded H-bridge based Static Var Generator (SVG) for voltage regulation of the Point of Common Coupling (PCC). To enhance its capability in gridfriendly integration and operation of renewable power plants, this paper proposed an energy-type Static-var-generator (ESVG) with grid forming (GFM) control characteristics. First, the energy type SVG's converter typology is presented, then a new type of grid forming control utilizing the distributed energy of SVG's dc capacitor is proposed, having two main characteristics: 1) it achieves autonomous frequency response and grid voltage support similar to the majority of GFM controls; 2) it has the self dc-voltage balancing capability, which does not require additional energy management control. The state-space model is also built to assess the small-signal stability of the ESVG system. Finally, an electromagnetic transient (EMT) simulation model of a typical grid-tied ESVG system is constructed in Matlab/Simulink, and simulation results show that the proposed control methods and associated characteristics are valid.