基于相位补偿和交叉前馈补偿的VSG功率振荡抑制策略

针对虚拟同步发电机（VSG）潜在的同步频率处功率振荡问题，建立二阶VSG的小信号动态模型，分析VSG输出功率与虚拟电动势、功角的关系，指出较小的线路阻抗比R/X使控制系统在同步频率处存在谐振点，且引入的180°的滞后相位降低了系统稳定性，促进了功率振荡的产生.通过建立VSG控制环的频域模型，分析小线路阻抗比时功率控制参数对功率振荡的影响，给出功率耦合与稳定性的关系.根据功率振荡的产生机理及模型分析，引入相位补偿和交叉前馈补偿的2种补偿策略来抑制同步频率处的功率振荡.通过搭建的仿真模型，验证VSG存在的功率振荡现象以及2种补偿抑制策略的有效性.

VSG power oscillation suppression strategies based on phase compensation and cross feedforward compensation

A small signal dynamic model was derived for the second-order virtual synchronous generator (VSG) model to analyze the relationship between VSG output power and virtual electromotive force/power angle, aiming at the power oscillation problem at synchronous frequency of VSG. There was resonance point at synchronous frequency caused by the small line impendence ratio R/X. Furthermore, the 180° phase lag was introduced at the resonance point, which reduced the control stability and facilitated the power oscillation. Moreover, the frequency domain model of VSG control was established to analyze the influence of power control parameters on power oscillation at small line impedance ratio, and the relationship between power coupling and the stability of control system was given. According to the mechanism of power oscillation and the analysis of frequency domain model, two kinds of compensation strategies, phase compensation and cross feedforward compensation, were proposed to suppress the power oscillation at the synchronous frequency. Finally, the power oscillation phenomenon and the effectiveness of the two suppression strategies are verified through computer simulation.