摘要
针对具有工频隔离变压器和LC滤波环节的三相复合功能并网逆变器,将其等效变换为带有LCL滤波器的逆变器结构。利用LCL滤波环节的状态方程建立小信号模型,提出了一种基于线性二次型理论的最优控制策略,在消除了LCL滤波器固有的谐振现象的同时,实现了对并网点PCC处谐波、无功和不平衡电流的补偿,提高了并网点处的电能质量。为了提高系统稳定性,给出了与线性最优控制相适应的前馈控制算法,并采用了无锁相环补偿电流和功率跟踪电流生成算法。利用电磁暂态综合分析程序PSCAD/EMTDC的仿真结果验证了所提方法的正确性和有效性。
The topology of a three-phase multi-functional grid-connected inverter with isolation transformer and LC filtering sections is converted into an equivalent structure of an inverter with LCL filter. The smallsignal model of LCL filter is built based on its state equation and a linear quadratic optimal control strategy is proposed,which eliminates the inherent resonance phenomenon of LCL filter,compensates the harmonics,reactive power and unbalanced currents at the PCC（Point of Common Coupling）,and improves the power quality of PCC. In order to enhance the system stability,a feedforward control algorithm is utilized to adapt to the linear quadratic optimal control and a PLL-less algorithm is applied to generate the compensating current and power tracking current. Simulative result with PSCAD / EMTDC verifies the correctness and validity of the proposed control strategy.
出处
《电力自动化设备》
EI
CSCD
北大核心
2016年第1期135-142,148,共9页
Electric Power Automation Equipment
基金
国家高技术研究发展计划(863计划)资助项目(2011-AA050204)
国家自然科学基金资助项目(50907060)~~
关键词
复合功能并网逆变器
LCL滤波器
线性二次型最优控制
前馈控制
multi-functional grid-connected inverter
LCL filter
linear quadratic optimal control
feedforward control
