两相静止坐标系下并网逆变器的自抗扰控制

针对三相并网逆变器入网电流控制中存在的电网不确定扰动、系统在dq坐标系下存在耦合以及传统控制器设计依赖精确数学模型等问题,提出了一种基于两相静止坐标系下的线性自抗扰控制(LADRC)策略,以T型三电平LCL并网逆变器为被控对象,设计了三阶线性自抗扰控制器。通过系统的等效传递函数,详细分析了逆变系统的稳定性以及抗扰性,并通过仿真和实验验证了所提控制策略的有效性。结果表明,所设计的控制策略能够提高T型三电平LCL并网逆变器的稳定性和抗扰性,实现了对入网电流的良好控制,其总谐波失真控制在2.2%。同时采用的“带宽化”参数整定方法,物理意义明确,参数调节简便,具有较高的工程应用价值。

Active disturbance rejection control of grid-connected inverter in stationary reference frame

Aiming at the problems of grid uncertainty disturbance in grid-connected current control of three-phase grid-connected inverter, system coupling in dq coordinate system and the dependence of traditional controller design on accurate mathematical model, a linear active disturbance rejection control strategy based on two-phase stationary coordinate system is proposed. Taking T-type three-level LCL grid-connected inverter as the controlled object, a three-order linear active disturbance rejection controller is designed. Through the equivalent transfer function of the system, the stability and immunity of the inverter system are analyzed in detail, and the effectiveness of the proposed control strategy is verified by simulation and experiment. The results show that the designed control strategy can improve the stability and immunity of T-type three-level LCL grid-connected inverter, and achieve good control of the grid current, and the total harmonic distortion is controlled at 2.2 %. At the same time, the '' bandwidth '' parameter tuning method has clear physical meaning, simple parameter adjustment and high engineering application value.