基于虚拟同步发电机的储能逆变器控制策略及无缝切换技术

Control Strategy and Seamless Switching Technology of Energy Storage Inverter Based on Virtual Synchronous Generator

为应对储能逆变器在并离网切换时产生的电压波动和冲击电流,基于微网孤岛和并网运行模式的特点,提出虚拟同步发电机(virtual synchronous generator,VSG)控制策略。通过对微网无缝切换关键技术分析,提出基于频率扰动的微网预同步控制。为实现控制策略的无缝切换,利用VSG控制和有功和无功功率(PQ)控制共用电流内环,实现外环参考电流平滑过渡,确保控制策略切换时刻和公共耦合点(point of common coupling,PCC)开关动作时刻的同步性,保证了VSG在两种运行模式之间平滑切换,有利于微网的稳定运行。在MATLAB/Simulink仿真平台下搭建模型,验证所提控制策略和切换方法的有效性和可行性。

In order to cope with the voltage fluctuation and inrush current generated when the inverter is switched on and off from the grid,a virtual synchronous generator(VSG)control strategy was proposed according to the characteristics of microgrid islanding and grid-connected operation mode.Through the analysis of the key technology of seamless transfer of microgrid,the pre-synchronization control of microgrid based on frequency disturbance was proposed.In order to realize the seamless switching of control strategy,VSG control and active and reactive power(PQ)control were used to control the common current inner loop to realize the smooth transition of the reference current of the outer loop,ensure the synchronization of the control strategy switching time and the point of common coupling(PCC)switch action time,and ensure that the VSG is in two operating modes smooth switching between the two is conducive to the stable operation of the microgrid.The model was built on the MATLAB/Simulink simulation platform to verify the effectiveness and feasibility of the proposed control strategy and switching method.