【目的】随着新能源在电力系统中的占比不断提高,构网型变流器由于具有较好的电压主动支撑能力而取得广泛的关注与研究。但是在偏远的低压配电网下,配电网的线路阻感比较大,会引起构网型变流器的功率耦合,进而影响变流器基波电压支撑能力以及功率传输能力。本文针对配电网下考虑阻感比变化的构网型变流器功率耦合问题展开研究,提出了一种采用前馈解耦的控制策略。【方法】通过在解耦通道上增加低通滤波器(LPF)的方法提高系统鲁棒性,并通过小信号法分析了不同LPF带宽对系统稳定性的影响。【结果】在采用前馈解耦后,有功功率控制回路和无功功率控制回路之间的耦合大大降低,解决了配电网阻感比较大导致的功率耦合问题,最后仿真结果验证了所提方法的可行性。【结论】本文所提方法能够实现良好的解耦效果,为构网型变流器中的功率传输提供了一种高鲁棒性的控制方案。

[Objective] As the proportion of renewable energy in the power system continues to rise, grid-forming converters have garnered significant attention and research interest due to their superior voltage support capabilities. However, in remote low-voltage distribution networks, the ratio of line resistance-inductance is relatively high. This can lead to power coupling issues in grid-forming converters, adversely impacting their fundamental voltage support and power transmission capabilities. This paper addresses the power coupling issues in grid-forming converters, considering changes in the resistance-inductance ratio in distribution networks. A control strategy employing feedforward decoupling is proposed. [Methods] The robustness of the system was improved by adding low-pass filter (LPF) into the decoupling channel. The impact of different LPF bandwidths on system stability was analyzed using the small signal method. [Results] Upon implementing feedforward decoupling, the coupling between the active and reactive power control loops was significantly reduced, effectively resolving the power coupling issues caused by the high resistance-inductance ratio of the distribution network. [Conclusion] The proposed method can achieve effective decoupling and provides a highly robust control strategy for power transmission in grid-forming converters.