虚拟稳态同步负阻抗的VSG功率解耦策略

Virtual steady state synchronous negative impedance of a VSG power decoupling strategy

伴随着分布式能源渗透率的逐渐提高,电力系统中的转动惯量相对减小,严重影响到系统安全稳定运行。其中虚拟同步发电机(Virtual Synchronous Generator,VSG)因具备同步发电机的相关特性而备受关注。针对VSG实际输出端口点到并网点的传输功率过程中存在耦合而引起VSG功率控制产生稳态误差和动态振荡,从而引起下垂特性的变化的情况,在对动静态功率耦合机理分析的基础上,提出基于虚拟稳态同步负阻抗的功率解耦策略,更好地消除了功率环间的耦合作用。通过建立基于所提出的VSG新型功率解耦策略的全局状态空间小信号模型,证明了该解耦策略的有效性。最后,搭建了基于解耦策略的VSG实验平台。通过实验结果验证了所提解耦策略的有效性,消除了功率环间的耦合作用,增强了VSG有功功率和无功功率的动静态响应性能。

With the gradual increase of the rate of distributed energy penetration,the moment of inertia in the power system is relatively reduced.This seriously affects the safe and stable operation of the system.The Virtual Synchronous Generator(VSG)has attracted attention because of the related characteristics of synchronous generators.Coupling in the transmission power of the VSG actual output port point to the grid-connected point causes the VSG power control to generate steady-state error and dynamic oscillation,thereby causing a change in the droop characteristic.Based on the analysis of the dynamic and static power coupling mechanism,this paper proposes a power decoupling strategy based on virtual steady-state synchronous negative impedance,which better eliminates the coupling effect between power loops.The global state space small-signal model based on the new VSG power decoupling strategy is established,and the effectiveness of the decoupling strategy is proved.Finally,the VSG experimental platform based on the decoupling strategy is built.The experimental results verify the effectiveness of the strategy,and show the elimination of the coupling between power loops,and the enhancement of the dynamic and static response of VSG active power and reactive power.