基于能量函数法的含虚拟惯性控制直驱风电场内部暂态同步稳定性分析

直驱风电机组的同步稳定性与锁相环动态特性紧密相关，锁相环同步失稳易引发风电场大规模脱网。为此提出一种基于能量函数法的直驱风电场内部暂态同步稳定性定量分析方法。首先，在一定假设条件下，保留惯性控制和外环控制对锁相环动态特性的影响，对直驱风机并网控制系统进行降阶。然后，在降阶控制系统的基础上，推导出计及惯性控制和外环控制影响的直驱风机广义摇摆方程。基于广义摇摆方程，利用首次积分法建立机组级风机暂态能量函数，在直驱风电场等效线路模型的基础上进一步推导出多风机暂态能量函数，并采用势能界面法确定系统临界能量值。最后，在直驱风电场四机系统中进行仿真分析，证明了该能量函数的有效性和准确性，并进一步分析了惯性控制参数对同步稳定性的影响。

Transient synchronization stability analysis of PMSG-based wind farm with virtualinertial control based on an energy function method

The synchronization stability of a direct drive permanent magnet synchronous generator (PMSG) is closely related to the dynamic characteristics of the phase-locked loop (PLL). The loss of synchronization stability may easily lead to massive disconnection of wind farm. To this end, a quantitative analysis method based on energy function method to analyze the transient synchronization stability of PMSG-based wind farms. Based on certain assumptions, this paper first reduces the order of the grid-side control system of the PMSG on the premise of retaining the influence of inertial control and outer-loop control on the dynamic characteristics of the PLL. Then, based on a reduced order control system, the generalized swing equation of the PMSG considering the influence of inertial control and outer-loop control is established. Based on the generalized swing equation, the first integration method is used to derive the unit level transient energy function. Based on the grid connected equivalent circuit of the PMSG-based wind farm, the transient energy function at the station level is derived, and the critical energy value of the system is determined by the potential energy boundary surface method. Finally, the correctness of the derived results and the effectiveness of the energy function are verified in the four-machine system of a PMSG-based wind farm. The influence of inertial control parameters on synchronization stability is also analyzed. This work is supported by the National Natural Science Foundation of China (No. 51637005).