STATCOM and synchronous generator are considered as measures of providing dynamic reactive power to power grid. Based on a real regional power grid, ability of voltage support between STATCOM and generator are compared through digital simulations. The results shows that STATCOM always provides additional reactive power to persist voltage collapse, while ability of generator reactive power are restricted by terminal voltage under faults.

A unified control structure for two-stage power converter system (PCS) is proposed which incorporates both charging and discharging modes within the same controller. Detailed modeling process is presented using sub-system approach. Power feed-forward compensation with direct battery current reference is engaged to enable fast response to power change on battery side, thus reducing DC bus voltage fluctuation during transients. Simulation and experiments show that the proposed control structure can effectively improve dynamic response without compromising steady-state performance.