虚拟同步发电机稳定性分析与参数设计

Stability Analysis and Parameter Designing for Virtual Synchronous Generator

在电压电流双闭环内核外级联功率控制外环构成的虚拟同步发电机(VSG)控制方案可引入惯性到逆变器中,从而增强并网后对系统稳定性的支持。针对此种VSG的参数设计和稳定性问题,提出了一种由线性化系统模型特征值灵敏度矩阵引导的VSG参数整定方法。由于级联控制回路之间的相互作用以及系统动态对控制器参数的复杂依赖性,使传统的参数整定方法在低开关频率下效果欠佳。而新方案以迭代优化的形式实现,可确保系统稳定性,并使系统特性值从关键位置处移开。最后,开展了时域对比仿真,验证了相对于传统参数设计方案,采用新方案设计的参数明显改善了VSG的动态性能。

The virtual synchronous generator(VSG)control scheme formed by the cascaded outer power control loop in voltage and current double closed loop core can introduce inertia into the inverter,so as to enhance the stability of the system after grid connection.Aiming at the parameter design and stability of this VSG,a VSG parameter tuning method guided by the eigenvalue sensitivity matrix of the linearized system model was proposed.Due to the interactions between the cascaded control loops and the complex dependence of the system dynamics on the controller parameters,the traditional parameter tuning method is not effective at low switching frequencies.The new solution was implemented in an iteratively optimized form to ensure system stability and remove system eigenvalues from critical locations.Finally,a time-domain comparison simulation was carried out to verify that the parameters designed with the new scheme significantly and improve the dynamic performance of the VSG compared to the traditional parameter design scheme.