孤岛微电网逆变器不平衡负载下的控制策略  

Control strategy of inverter for islanded microgrid with unbalanced load

作　　者：陈强[1] 章心因[1] 吕干云[1] CHEN Qiang;ZHANG Xinyin;LÜ Ganyun(School of Electric Power Engineering,Nanjing Institute of Technology,Nanjing 211167,China)

机构地区：[1]南京工程学院电力工程学院,江苏南京211167

出　　处：《电力自动化设备》2021年第2期124-130,共7页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51577086)。

摘　　要：提出一种孤岛微电网逆变器在不平衡负载下的控制策略,采用分序网络解耦控制,在虚拟同步发电机(VSG)控制的基础上引入自适应负序补偿环。对三相负载不平衡下的电路进行分析,得到逆变器分序网络等效电路和逆变器间负序环流产生机理。通过分序网络解耦控制得到电压环参考电压各序分量,引入分序网络虚拟阻抗改进逆变器各序输出阻抗。正序网络采用VSG控制实现正序调频调压和电流的自主分配,负序网络加入负序补偿环抑制微电网三相电压负序分量。详细分析了微电网电压负序分量与负序补偿系数和逆变器输出电流负序分量的关系。负序补偿环采用自适应控制,在实现微电网三相电压平衡的同时根据逆变器额定容量自主分配输出电流负序分量。建模仿真结果验证了所提控制策略的有效性。A control strategy of inverter for islanded microgrid with unbalanced load is proposed,which adopts the sequence network decoupling control and introduces adaptive negative sequence compensation loop based on VSG(Virtual Synchronous Generator)control.Based on analyzing the circuit with unbalanced three-phase load,the sequence network equivalent circuit of inverter and the generating mechanism of negative sequence circulation between inverters are obtained.Sequence network decoupling control is employed to obtain each sequence component of reference voltage of voltage loop,and sequence network virtual impedance is added to improve each sequence output impedance of inverter.VSG control is used in positive sequence network to realize positive sequence frequency and voltage regulation and current autonomous distribution,and negative sequence compensation loop is adopted in negative sequence network to suppress the negative sequence component of three-phase voltage of microgrid.The relationship among the negative sequence component of microgrid voltage,the negative sequence compensation coefficient and the negative sequence component of output current of inverter is analyzed in detail.The adaptive control is used in negative sequence compensation loop to realize three-phase voltage balance of microgrid and the independent distribution of negative sequence component of output current according to the inverter rated capacity.Modeling simulative results verify the effectiveness of the proposed control strategy.

关 键 词：不平衡负载 孤岛微电网 逆变器 分序网络解耦控制 虚拟同步发电机 自适应负序补偿环 

分 类 号：TM712[电气工程—电力系统及自动化] TM464[电气工程—电器]