Evaluating Grid Support Features of Voltage Source Inverter: An Analysis of Direct Power Control

This paper presents the dynamic modeling of a voltage source inverter (VSI) grid-connected system with high-performance direct power control (DPC) functions. The system is modeled in the stationary reference frame to reduce complexity and make it linear time-invariant, enhancing control flexibility. The DPC is introduced to achieve fast reference tracking and decoupling regulation of grid active and reactive power injection. Simulation results demonstrate that the DPC exhibits a fast dynamic response and adaptable to changes in grid parasitic elements, even under weak grid conditions with short-circuit ratio of 1.8. The insights and discussions provided in this paper will be valuable for researchers, engineers, and professionals in the industry working on VSI-grid integration and developing control strategies.