基于VSG控制的微网逆变器最优虚拟惯性研究

Research on Optimal Virtual Inertia of Micro-Grid Inverter Based on VSG Control

为了能够支撑微电网的电压和频率，提高微电网运行的稳定性，本文针对采用虚拟同步发电机（VSG）控制策略的微网逆变器进行了研究。由于VSG中虚拟惯性的存在，在功率调度指令突变时，微网逆变器的频率和输出功率会发生振荡，严重时将导致逆变器因过流保护而停机。本文在功率闭环传递函数根轨迹分析影响VSG稳定性和动态性能的参数变化范围的基础上，采用线性二次型最优控制，以功率和频率变化量为约束条件，提出了最优虚拟惯性控制策略，通过对VSG参数进行优化配置解决了上述问题。Matlab仿真和实验结果验证了该控制策略的正确性和有效性。

In order to support the voltage and frequency of micro-grid and improve the stability of it, micro-grid inverter based on virtual synchronous generator control is studied in this paper. Due to the existence of virtual inertia in the VSG, the frequency and output power of micro-grid inverter will oscillate and the inverter will break down in severe cases due to over-current protection. Firstly, on the basis of power closed loop transfer function, a detail analysis was available to quantify the scope of the influence of VSG parameter variation on the stability and dynamic performance of the system by root locus. Besides, with power and frequency change as the constraint condition, an optimal virtual inertia control strategy based on the linear quadratic optimal control was proposed. Additionally, these problems were solved through the optimization of the parameters of VSG. Finally, simulated results on Matlab and experimental results were utilized to confirm the validation and feasibility of the proposed control strategy.