直流微网双向DC/DC变换器虚拟惯量和阻尼系数自适应控制策略

A self-adaptive control strategy of virtual inertia and a damping coefficient for bidirectional DC-DC converters in a DC microgrid

在高新能源渗透率下的直流微网系统中,电力电子器件比例不断提高,导致系统存在低惯性问题,降低系统运行稳定性。为此提出了一种改进的虚拟惯量和阻尼系数自适应控制策略。该方法通过类比交流系统逆变器的虚拟直流发电机控制,分析直流微网系统在虚拟惯量和阻尼系数控制下负荷扰动量与输出电压扰动量的关系特性,将自适应控制策略引入虚拟惯量和阻尼系数。通过建立小信号模型,利用系统输出阻抗结合阻抗比判据给出虚拟惯量和阻尼系数的变化范围和边界,分析虚拟惯量和阻尼系数自适应选取下系统惯性变化及母线电压响应效果,该方法提高了直流微网系统惯性,同时改善了直流母线的动态响应。最后通过Matlab/Simulink仿真和RT-LAB半实物实验,验证了所提控制策略的有效性。

In a DC microgrid system with high penetration of new energy,the proportion of power electronic devices continues to increase.This leads to the problem of low inertia in the system and reduces the stability of the system.Therefore,an improved adaptive control strategy of virtual inertia and a damping coefficient is proposed.This method analyzes the relationship between load disturbance and output voltage disturbance in the DC microgrid system under the control of virtual inertia and damping coefficient by analogy to the virtual DC generator control of the inverter of the AC system,and introduces an adaptive control strategy into virtual inertia and the damping coefficient.By establishing a small signal model,using the system output impedance combined with the impedance ratio criterion,the range and boundary of the virtual inertia and damping coefficient are given,and the effect of system inertia change and bus voltage response under the adaptive selection of virtual inertia and damping coefficient is analyzed.The strategy increases the inertia of the DC microgrid system and improves the dynamic response of the DC bus.Finally,Matlab/Simulink simulation and RT-LAB hardware in a loop experiment verify the effectiveness of the proposed control strategy.