孤岛微电网电压不平衡网络化分层补偿方法

摘要

针对多逆变器并联的低压孤岛微电网公共耦合点(PCC)接入不对称负荷引起的三相电压不平衡问题,提出网络化分层协同优化控制方法.基于通信技术和分层控制理论,建立网络化分层控制体系结构,包含本地控制层和分布式二次控制层.本地控制层采用下垂控制和虚拟阻抗,实现有功功率和无功功率分配.在二次控制中,采用动态一致性算法获取全局平均值,调节电压和无功功率的偏差,以实现电压无静差控制和功率的精确分配;结合优化控制策略实现PCC和分布式发电(DG)电压不平衡协同优化补偿控制.该方法不仅能很好地对PCC的电压进行补偿,还兼顾了各DG的电压质量.搭建半实物仿真实验平台,验证了所提方法的有效性和可行性.%Aiming at the problem of three-phase voltage unbalance caused by the integration of unbalance load at the PCC(Point of Common Coupling)in low voltage island microgrid with multiple parallel inverters,an optimal networked hierarchical coordinated control method is proposed.The networked hierarchical control system is built based on communication technology and hierarchical control theory,which includes local control layer and distributed secondary control layer.The local control layer adopts the droop control and virtual impedance to realize the distribution of active power and reactive power.In the secondary control,the dynamic consensus algorithm is adopted to obtain the global average value and adjust the deviations of voltage and reactive power for realizing astatic control of voltage and accurate distribution of power.Combined with optimization control strategy,the optimal coordinated compensation control of unbalance voltage for PCC and DG(Distributed Generator) is realized.The proposed method can well compensate voltage at PCC as well as ensure the voltage quality of each DG.The semi-physical simulation experimental platform is built to verify the effectiveness and feasibility of the proposed method.