基于频域RGA原理的多并联三相逆变器间交互影响分析

Analysis on Interactive Influences Among Multiple Parallel Three-phase Inverters Based on Frequency Domain RGA Principle

针对并联三相逆变器间的交互影响问题,提出了基于相对增益矩阵原理的并联变换器交互影响分析方法。在考虑非线性因素影响的基础上,建立了αβ坐标系下包含附加有源阻尼控制的双闭环控制逆变器传递函数模型,构建了基于下垂控制的LCL型逆变器并联系统等效模型,结合相对增益矩阵原理分析并联逆变器间交互影响程度,揭示了并联系统交互运行的相关规律。最后,在MATLAB/Simulink仿真平台中搭建了多三相逆变器并网模型,并通过仿真和实验验证了理论分析的正确性和交互影响分析方法的有效性。研究结果表明:多三相并网逆变器间交互影响程度主要受到系统运行频率、滤波电容数值和逆变器并联台数的影响。所提方法可定量分析逆变器间的交互影响程度,为逆变器控制系统优化设计及提高并联逆变器系统电能质量提供经验借鉴。

In order to solve the problem of interaction among three-phase parallel inverters, a method is proposed in this paper to analyze the interaction of parallel converters based on the principle of relative gain array. The influence of nonlinear factors is taken into consideration, so that the transfer function model of double closed-loop inverter with additional active damping control is established in the αβ coordinate system, and the equivalent model of LCL inverter parallel system based on droop control is constructed. Combined with the principle of relative gain array, the degree of interaction among parallel inverters is analyzed, and the relevant laws of interactive operation of parallel system are revealed. Finally,the model of multiple three-phase inverters grid-connected system is built on the Matlab/Simulink, and the correctness of theoretical analysis and the effectiveness of interaction analysis method are verified by simulations and experiments. The research results show that the interaction degree of multi three-phase grid-connected inverters is mainly affected by the system operating frequency, filter capacitance value and the number of parallel inverters. This method can be adopted to quantitatively analyze the degree of interaction among inverters, and provide experience for optimal design of inverter control system and improvement of power quality of parallel inverter system.