【摘要】 对于带锁相环的并网VSC大扰动稳定性问题，首先依据VSC的内环电流控制和外环功率控制响应速度差异得到简化二阶非线性模型，然后分别定义了两个李雅普诺夫函数。第一个李雅普诺夫函数具有清晰的动能和势能概念，但推导的稳定域较小，第二个李雅普诺夫函数推导的稳定域较大但缺乏清晰的物理概念。最后结合这两个李雅普诺夫函数，得到实用的稳定性判据，兼具明确的物理意义和较宽的稳定域。如果在系统最后一次动作时已知锁相环状态量，则可以预测系统稳定性。仿真结果验证了该判据的正确性。更多还原

【Abstract】 To study the large disturbance stability of a grid-connected VSC with phase-locked loop, a simplified second order nonlinear model of a VSC is established based on the difference of response speed between inner loop current control and outer loop power control, and two Lyapunov functions are separately defined. The first Lyapunov function has clear kinetic energy and potential energy concepts but a small stable region, while the second Lyapunov function has a wider stable region but lacks clear physical concepts. Combining the two Lyapunov functions, a practical stability criterion is obtained, one which has both clear physical concepts and a relatively large stable region. If the state of the phase-locked loop is known at the time of the system’s last operation, the stability can be predicted. The simulation results well verify the accuracy of the derived stability criterion.This work is supported by the Science and Technology Project of the Headquarters of State Grid Corporation of China(No. 5100-202055389A-0-0-00).更多还原