低开关频率下并网变换器的控制及稳定性分析  

CONTROLAND STABILITY ANALYSIS OF GRID-CONNECTED INVERTER UNDER LOW SWITCHING FREQUENCY

作　　者：黄鹭鹭 高波 Huang Lulu;Gao Bo(State Grid Shanghai Energy Interconnection Research Institute,Shanghai 201210,China)

机构地区：[1]国网上海能源互联网研究院有限公司,上海201210

出　　处：《太阳能学报》2023年第4期332-340,共9页Acta Energiae Solaris Sinica

基　　金：国家电网总部科技项目(SGAH0000KJJS2000680)。

摘　　要：分析LCL型并网变换器网侧电流反馈控制和变换器侧电流反馈控制阻尼系统的稳定性。从主导极点的角度分析低开关频率下2个共轭复根的位置决定了根轨迹的走向,进而影响系统的稳定。已有的有源阻尼方法都是各自独立提出的,缺乏系统的研究以便于提出新的有源阻尼控制方法,通过对并网变换器稳定控制的分析可得到阻尼控制方法的本质。数字延时本质上是一种串联校正,揭示了延时改变系统相位特性。数字延时的相位滞后在某些情况下有利于系统稳定,但这取决于测量反馈量的传感器位置和谐振频率。该文在离散域下对电流控制器参数进行设计,从工程实用的角度给出快速确定控制器参数的方法。最后通过仿真和试验验证理论分析的正确性。The stability of damping resonance of grid-side current feedback control and inverter-side current feedback control of LCL grid-connected inverter is analyzed.From the standpoint of the dominant poles,the positions of the two conjugate complex roots at low switching frequency determine the direction of the root locus,which in turn affects the stability of the system.The existing active damping methods are proposed independently,and there is a lack of systematic synthesis in order to propose novel active damping control methods.The essence of the damping resonance can be obtained by analyzing the stability control of grid-connected inverters.Digital time-delay is essentially a series correction,revealing that the delay changes the system phase characteristics.The phase lag of the digital delay is beneficial to system stability in some cases,but it depends on resonance frequency and the position of current sensor which is utilized for feedback variable.The paper designs the current controller parameters in the discrete domain,and gives a method to determine controller parameters quickly and exactly from the point of view of engineering practicality.The theoretical analysis is validated by simulation and experimental results.

关 键 词：LCL滤波器 电流控制器 网侧电流反馈 变换器侧电流反馈 数字延时 相位滞后 

分 类 号：TK513.5[动力工程及工程热物理—热能工程]