虚拟同步发电机暂态全局稳定分析与阻尼调制方法

Unlike traditional synchronous generators, the damping of virtual synchronous generators(VSG) can be flexibly adjusted to enhance the dynamic performance of the system. In order to reveal the stabilization mechanism of VSG system, the global stability mechanism of VSG system considering the damping effect is analyzed. First, the dynamic model of VSG system is established, and the stable domain of the system is derived based on the Lyapunov theory. Accordingly, based on the law of conservation of energy, it is interesting to find that the energy dissipated by the damping is equal to the damping factor multiplied by the area surrounded by the system trajectory and x-axis in the phase plane. The research results show that when the dissipated energy induced by damping over one period is larger than potential energy change, the system kinetic energy will be gradually decreased until to zero, and the global stabilization can be ensured. Then, a damping tuning method to ensure the global stability of the system is further proposed. Finally, simulation studies based on PSCAD/EMTDC have validated the correctness of the proposed global stability condition and the effectiveness of the damping tuning method of VSG.