Damping Characteristic Analysis of Grid-forming PMSG-based WT under Different Reactive Power Oscillation Damping Controls

Grid-forming control has been recognized as a flexible and robust solution for wind turbine (WT) integrating into weak AC grid in the research community. This paper investigates the damping properties of the grid-forming permanent magnet synchronous generator (PMSG)-based WT under different reactive power oscillation damping controls. First, a recently developed grid-forming control, namely, the DC voltage synchronization control (DVSC), is implemented in PMSG-based WT, enabling WT with capabilities of inertial response and grid-synchronization without the phase- locked loop (PLL). Then, two different reactive power controls, i.e., the convert er voltage control and the reactive power droop control, are further designed with corresponding damping controllers. Moreover, the impacts of associated control parameters and operating conditions on system damping characteristics are substantially and analytically evaluated, which can provide guidance for parameter tuning. The proposed damping controls stand out by: 1) fully utilizing the capacity of the converter and the reserved energy in DC capacitor to contribute to system damping support, 2) not impairing maximum power point track (MPPT) status of WT. Case studies are conducted under several power system contingencies to validate the effectiveness of the proposed damping control.