构网型变流器的序域等效模型及限流方法

Sequence Domain Equivalent Model and Current Limiting Method for Grid-forming Converters

为了了解变流器在故障情况下的响应,基于三相三线制构网型变流器的下垂控制策略,详细讨论了变流器在正序、负序和零序下的输出阻抗并加以分析,提出了对应的阻抗简化模型。同时分析了矢量直接限流法的不足,提出了基于虚拟阻抗对过电流进行限制的方法。最后,通过MATLAB/Simulink对故障情况进行仿真,进一步验证了等效模型以及所提限流方法的正确性。

In order to understand the response of the inverter under fault conditions,a droop control strategy based on a three-phase three-wire grid type inverter was proposed.The output impedance of the inverter in positive sequence,negative sequence,and zero sequence was discussed in detail and analyzed.A simplified impedance model was proposed.The shortcomings of the vector direct current limiting method were analyzed and a method based on virtual impedance to limit overcurrent was proposed.Finally,the fault situation was simulated using MATLAB/Simulink to further verify the correctness of the equivalent model and the proposed current limiting method.