跟网型逆变器作为电流源型变换器,在电网强度、负载变化和电网波动的扰动下,其输出电流会发生波动,进而通过电网阻抗引发公共耦合点电压振荡.构网型逆变器作为电压源型变换器,可用于模拟同步发电机调节电压且无须依赖锁相环,在弱电网中表现出更强鲁棒性.针对跟网型逆变器在弱电网运行时存在的稳定性问题及传统改进策略在控制稳定性和参数设计上的局限性,提出基于线性自抗扰控制(Linear active disturbance rejection control,LADRC)的构网型逆变器电压协调控制方法,通过扩张状态观测器补偿公共耦合点扰动,降低跟网型逆变器电压对电流的敏感性.与传统控制相比,用该方法可显著降低构网型逆变器输出阻抗、减小非无源区域、提高电压调节性能及弱电网下稳定性.仿真结果验证了所提策略的有效性.
Voltage Coordinated Control of Grid-forming Converters Based on LADRC Strategy in Weak Grids
As current-source converters,grid-following inverters will experience output current fluctuations under the disturbances of grid strength,load changes,and grid fluctuations,which in turn can cause voltage oscillations at the point of common coupling(PCC)through the grid impedance.In contrast,grid-forming inverters,operating as voltage-source converters,can be used to simulate synchronous generators to regulate voltage without relying on phase-locked loops,demonstrating greater robustness in weak grids.To address the stability issues of grid-following inverters operating in weak grids and the limitations of traditional improvement strategies in control stability and parameter design,a voltage coordinated control method for grid-forming inverters based on linear active disturbance rejection control(LADRC)is proposed,which employs an extended state observer to compensate for point of commom coupling disturbances,reducing the sensitivity of the grid-following inverter's voltage to current variations.Compared with conventional control approaches,the proposed method significantly reduces the output impedance of grid-forming inverters,minimizes non-passive regions,and enhances voltage regulation performance and the stability in weak grids.Simulation results validate the effectiveness of the proposed strategy.
GFMGFLweak gridLADRCoutput impedancecoordinated control
万方数据
维普
