基于模型预测控制的直流微电网电压动态响应优化  

Voltage Dynamic Response Optimization of DC Microgrid Based on Model Predictive Control

作　　者：朱晓荣[1] 候顺达 李铮[1] ZHU Xiaorong;HOU Shunda;LI Zheng(Hebei Key Laboratory of Distributed Energy Storage and Micro-grid(North China Electric Power University),Baoding 071003,Hebei Province,China)

机构地区：[1]分布式储能与微网河北省重点实验室(华北电力大学),河北省保定市071003

出　　处：《电网技术》2020年第6期2187-2195,共9页Power System Technology

摘　　要：基于下垂控制的直流微电网在负荷频繁投切时母线电压会急剧波动,严重影响直流电压的电能质量。直流电容可以阻碍直流母线电压的突变,但是过大的直流电容又会延长系统达到稳态的时间。提出了一种基于模型预测控制的直流微电网电压动态响应优化方法,在负荷突变时采用较大的虚拟电容减缓直流电压的变化,在动态响应后期采用较小的虚拟电容使直流电压快速达到稳态。首先给出蓄电池侧虚拟电容的工作原理,通过模型预测控制得到最佳的虚拟电容值,并作用于DC/DC换流器的虚拟电容控制上;其次设计了电流内环的模型预测控制器;最后比较了电流内环分别为PI控制和有限集模型预测控制时对直流母线电压动态响应的影响。基于RT-LAB建立了直流微网仿真模型,仿真结果验证了所提控制的有效性。The DC voltage of the DC microgrid based on the droop control will fluctuate sharply when the load is frequently switched,which seriously affects the power quality of the DC voltage.DC capacitors can block the sudden changes in the DC bus voltage,while the excessive DC capacitors will extend the duration that the system reaches its steady state.This paper proposes a voltage dynamic response optimization method of DC microgrid based on model predictive control.When the load is abrupt,a large virtual capacitor is used to slow down the change of the DC voltage.However,in the later stage of the dynamic response,a small virtual capacitor is used to reach the DC voltage to the steady state quickly.Firstly,the working principle of the battery side virtual capacitor is given.The optimal virtual capacitor value is obtained through model predictive control and applied to the additional virtual capacitor control of the DC/DC converter.Secondly,the model predictive controller of the current inner loop is designed.Finally,the effects of the current inner loop on the dynamic response of the DC bus voltage during PI control and FCS-MPC(finite control set model predictive control)is compared.The simulation model of DC microgrid is established based on RT-LAB.The simulation results verify the effectiveness of the proposed control.

关 键 词：直流微网 虚拟电容 模型预测控制 动态优化 双向DC-DC变换器 

分 类 号：TM721[电气工程—电力系统及自动化]