基于同步虚拟阻尼的多虚拟同步发电机功率振荡抑制策略

Power Oscillation Suppression Strategy for Multi-VSGs Based on Synchronous Virtual Damping

当由多虚拟同步发电机(virtual synchronous generator,VSG)组成的电网遭受外部扰动时,源端会出现功率振荡,影响系统的稳定运行。为解决这个问题,提出一种基于同步虚拟阻尼的多VSG功率振荡抑制策略;建立多VSG系统的传函模型,分析功率振荡的主要原因;通过功率下垂的比例微分特性,推导出同步虚拟阻尼的数学模型,并用于同步VSG控制环路中,从而增加系统在暂态情况下的等效阻尼,抑制系统的功率振荡。另外,通过构造能量函数的方法证明改进后系统的稳定性。最后,通过仿真验证了该控制策略抑制系统功率振荡的有效性。

In the event of external disturbance to a power grid consisting of multiple virtual synchronous generators(VSGs),power oscillations may arise among the VSGs,potentially affecting system stability.Aiming at this problem,a multi-VSG power oscillation suppression strategy based on synchronous virtual damping was proposed.A transfer function model of the multi-VSG system was established to analyze the primary causes behind power oscillation.According to the proportionaldifferential characteristics of the power droop,the synchronous virtual damping was deduced.The mathematical model was applied in the synchronous VSG control loop,increasing the equivalent damping of the system under transient conditions and thereby suppressing the power oscillation of the system.In addition,the stability of the improved system was proved through the construction of the energy function.Finally,the effectiveness of the control strategy in suppressing system power oscillations was confirmed by simulation.