提升组网型变流器并网交互稳定性的控制参数整定方法

Parameter Tuning for Improving Interaction Stability of Grid-forming Converter and Power Grid

当组网型变流器与电网发生交互振荡时,调节变流器的控制参数来改善其阻抗特性是提升其与电网的交互稳定性的重要措施。为提出适用于不同的组网型变流器的简洁通用的参数整定方法,采用解析方法对不同的组网型变流器控制参数影响序阻抗的规律进行了统一分析。分析结果表明,在非极端参数下,有功功率环参数只影响基频附近非常窄的频段的序阻抗,电压环参数在宽频段内均对序阻抗有显著影响,电流环比例系数在中高频段影响序阻抗。进一步地,根据分析结果总结出了一套简洁通用的调参原则,即在非极端参数下,适当地增大惯量或电压环比例系数,或者降低电压环积分系数,均有利于避免次同步频段的交互振荡。这为提高变流器并网系统交互稳定性的控制参数整定提供了一般指导。实验结果证明了分析结果和调参方法的正确性。

When the grid-forming converter oscillates interactively with the power grid, tuning the control parameters of the converter to improve its impedance characteristics is an important measure to enhance the interactive stability between the converter and the grid. Aiming to reveal the general rules,this paper analytically investigates the control parameter’s influence on the impedance. Under non-extreme parameters,the active power loop parameters only affect the sequence impedance in a very narrow frequency band near the fundamental frequency;the voltage loop parameters have a significant impact on the sequence impedance in a wide frequency band, and the current loop proportional coefficient affects the sequence impedance in the middle-high frequency band. Based on the analysis results, the general parameter tuning rules are proposed, i.e., under non-extreme parameters,appropriately increasing the inertia or the proportional coefficient of the voltage loop, or reducing the integral coefficient of the voltage loop, are beneficial to avoid the interactive oscillation in the sub-synchronous frequency band.These conclusions provide a general guidance to the parameter tuning for the interaction stability improvement. Experimental results verify the correctness of the theoretical analysis.