孤网模式下交直流混合微电网互联变换器综合下垂控制

互联变换器的控制方式直接影响交直流微网的稳定运行。分析研究了交直流互联变换器在孤网运行下基于下垂理论的控制方式,包括双下垂控制、下垂特性单位化控制、基于单位化混合下垂控制,针对其在功率流动方向判定和功率参考值选取的不足,提出了一种基于综合下垂系数的控制策略,具体论述了综合下垂系数的求取过程,定义了交直流混合微电网系统下垂系数比,比较混合微网功率盈余与缺额值,将较小值作为互联变换器的功率参考值,最大程度地减小了单个子网偏离额定运行条件下对联络子网的影响。最后利用Matlab/Simulink仿真软件,搭建交直流混合微电网仿真模型,验证了所提控制策略的可行性和有效性。

Integrated droop control of AC/DC hybrid microgrid interlinking converter in isolated network mode

The control mode of interlinking converter directly affects the stable operation of AC/DC microgrid. The control method based on droop theory of AC/DC interlinking converter under isolated network operation is analyzed, including bidirectional droop control, unitized control of droop characteristics, and unitized hybrid droop control. For power flow direction determination and power reference value selection of insufficiency, a control strategy based on integrated droop coefficient is proposed. The process of calculating the integrated droop coefficient is discussed in detail. The droop coefficient ratio of AC/DC hybrid microgrid system is defined. The hybrid microgrid power surplus and deficiency value are compared. The small value acts as a power reference for the interconnected converter, minimizing the impact of a single subnet on the contact subnet from deviating the rated operating conditions. Finally, the simulation model of AC/DC hybrid microgrid is built by using MATLAB/Simulink simulation software to verify the feasibility and effectiveness.