基于IDA-PBC的LCL滤波并网逆变器控制

Control Strategy Based on IDA-PBC for Grid-connected Inverter with LCL Filter

LCL滤波器作为并网逆变器与电网的重要接口,对开关引起的高次谐波衰减效果显著,但其存在数学模型阶数高和固有谐振峰等特点,易引起系统输出振荡。首先建立了LCL滤波三相并网逆变器的端口受控耗散哈密顿数学模型,然后提出了一种基于互联与阻尼配置的无源控制策略,从理论上保证了闭环系统的渐进稳定,并可很好地满足电网对并网逆变器动静态性能和谐波抑制能力的要求。在电磁暂态综合分析程序PSCAD/EMTDC环境中,通过在理想电网和畸变不平衡电网两种情况下的仿真实验,验证了所提控制策略的正确性、有效性与鲁棒性。

As an important grid interface for grid-connected inverter,LCL filter can effectively attenuate high frequency harmonics caused by switches.However,due to its high order mathematical model and natural resonant point,LCL filter is easy to bring the instability problem.Firstly,a port-controlled Hamiltonian mathematical model was built for three-phase grid-connected inverter with LCL filter.And then a new passivity-based control strategy based on interconnection and damping assignment was developed.The proposed method can asymptotically stabilize the close-loop system theoretically and well meet the demands of utility grid on static and dynamic performance of grid-connected inverter as well as on its ability of suppressing harmonics.The correctness,effectiveness and robust of this strategy were verified by the simulation based on PSCAD/EMTDC under both the ideal and non-idea grid voltage conditions.