基于线性化模型的虚拟同步发电机惯性和阻尼辨识

Estimation of Inertia and Damping for Virtual Synchronous Generator Based on Linearized Model

针对并网逆变器的虚拟同步发电机(VSG)控制,提出了一种VSG实际输出惯性和阻尼的辨识方法,以定量量化VSG参与电网调节能力的强弱。基于VSG的二阶非线性模型,及其在工作点附近的小信号摄动处理,建立了VSG的线性化传递函数模型,给出了其离散化模型及其与VSG惯性和阻尼参数之间的关系,分析了线性化模型的误差大小和适用范围。利用VSG的输出功率阶跃扰动,激励出VSG的功率振荡模态信息,并利用最小二乘估计的方法,辨识出VSG实际输出的惯性和阻尼参数。最后,针对并网逆变器的常规控制方法和VSG控制方法,利用仿真分析和实验结果,验证了所提模型和方法的可行性和有效性。

For the control of virtual synchronous generator （VSG） of grid-connected inverter, an approach is proposed to estimate the produced inertia and damping of VSG. Thus, the capability of VSG to participate in power grid adjustment can be quantified. Based on the second-order nonlinear model of VSG and its small signal perturbation processing ability near the working point, a linearized model for VSG is proposed. The discrete model of the linearized model is derived and its relation with inertia and damping parameters of VSG is given. The error magnitude and effective range of the linearized model are proposed. Using the output power step disturbance of VSG, the modal information on power oscillation of VSG is energized. Then, the least square method is utilized to estimate actual inertia and damping parameters of VSG. Finally, by taking the normal control and VSG control into account, simulated results and experimental measurements have confirmed the possibility and effectiveness of the proposed model and approach.