基于改进LADRC的构网型变换器预同步控制策略研究

Research on pre-synchronization control strategy of grid-forming converter based on improved LADRC

针对构网型变换器预同步过程时电力系统频率电压稳定性低导致变换器并网失败的问题,提出一种基于改进线性自抗扰控制(LADRC)的构网型变换器预同步控制策略。首先,采用无锁相环(PLL)控制策略,通过相位偏差的反馈控制对网侧电压的相位和幅值进行快速同步追踪,可避免因PLL精度较低和响应速度慢而引起的电力系统稳定性降低的问题。在此基础上,在有功频率支路模块的角频率输出端引入LADRC,这可以有效解决预同步控制过程中变换器输出电压频率存在过冲的问题,从而确保构网型变换器预同步控制顺利进行最终实现成功并网。最后,在MATLAB/Simulink仿真平台中搭建基于改进LADRC的构网型变换器预同步控制模型并进行仿真验证,结果表明所提控制策略可以有效抑制系统频率震荡,并能够加速系统预同步进程,确保构网型变换器安全运行最终实现成功并网,仿真结果验证了所提方法的有效性。

To address the problem of grid connection failure caused by low frequency and voltage stability in power system during pre-synchronization process of grid-forming converters,a pre-synchronization control strategy for grid-forming converters based on improved linear active disturbance rejection control(LADRC)is proposed.Firstly,the phase locked loop(PLL)control strategy is used to synchronize the phase and amplitude of the grid voltage with the feedback control of phase deviation,which can avoid the stability problems caused by low precision of the PLL and the slow response speed.On this basis,introducing LADRC in angular frequency output of the active frequency branch module can effectively suppress the frequency oscillation of the system,so as to ensure the normal pre-synchronization process of the grid-forming converter and realize successful grid-connection.Finally,on the MATLAB/Simulink simulation platform,a pre-synchronization control model for grid-forming converters based on improved LADRC is established verified through simulation.The results show that,the proposed strategy can effectively suppress the system frequency oscillations and accelerate the pre-synchronization process of the system,ensuring safe operation of the grid-forming converter and ultimately achieving successful grid connection.The simulation results verify the effectiveness of the proposed method.