分布式发电系统并网逆变器高稳态性能重复控制策略

High Steady-state Performance Repetitive Control Approach for Grid-connected Inverter of Distributed Generation System

提出一种应用于分布式发电系统并网逆变器的HSP-RC(高稳态性能重复控制)策略,采用四阶线性相位IIR(无穷脉冲响应)滤波器作为重复控制器的内模改进环节Q(z)。对比分析了Q(z)取常数、陷波滤波器、FIR(有限脉冲响应)滤波器与所提IIR滤波器时,系统的稳定性及系统对电网各次谐波的抑制性能。理论分析表明,得益于IIR滤波器具有平坦的通带和阻带内幅值衰减速度快的特点,HSP-RC可更有效地抑制电网的中高次(至20次)谐波,因此可进一步提高分布式发电系统的并网电流质量。仿真结果验证了所提控制策略的有效性和优越性。

This paper proposes a high steady-state performance repetitive control (HSP-RC) approach for grid-connected inverter of distributed generation system,which utilizes 4-order IIR (infinite impulse response) filter with linear phase serving as Q(z),the improved link of internal model of repetitive controller. In this paper,the comparative analysis of system stability and suppression performance against harmonics of system are carried out under the condition that Q(z) selects constant,notch filter,finite impulse filter(FIR) and the proposed IIR filter. Theoretical analysis demonstrates that benefiting from the great pass band flatness,high stop band attenuation of IIR filter,middle and high (up to 20 times) harmonics in power grid can be suppressed more effectively through HSP-RC,which can further improve the grid-connected current quality of distributed generation system. Simulation results verify the effectiveness and superiority of the proposed control approach.