全功率变换风电机组机侧换流器与交流系统间动态交互机理及对稳定性的影响

全功率变换风电机组通过一组背靠背连接的电压源换流器将风电功率注入交流电网。研究表明,网侧换流器与交流电网直接连接,其间可能出现强交互、导致系统在扰动作用下出现功率振荡现象。而对于机侧换流器与交流系统间是否有强交互的可能,其如何产生、又有何影响,当前未见有充分的理论分析与研究。为分析机侧系统与网侧系统间的动态交互作用,首先建立了将全功率变换风电机组视为由机侧系统和网侧系统构成的互联系统,并建立其小信号模型。然后,根据互联系统模型与系统框图,发现了风电机组机侧系统与网侧换流器甚至是交流电网间动态交互作用的通道、及影响因素。最后通过仿真算例,进一步分析与验证了机侧系统与网侧系统的动态交互的存在性及其影响。

Dynamic Interaction and Its Impact Between Machine-side Converters of Full-scale Power Conversion Wind Turbine Generator and AC Power System

The full-scale power converter wind turbine generators inject the wind power to the AC grid via a set of back-to-back voltage sourced converters.Researches have shown that the gird-side converters,directly connected to the AC grid,may have strong dynamic interactions in between,leading to power oscillations when a small disturbance occurs.However,as for the machine-side converters,it remains to be studied on whether there is a possibility of strong interactions between the converters and the AC grid,how the interactions occur and what impacts they have.To analyze the dynamic interaction between the machine-side system and the gird-side system,in this paper,the full-scale power converter wind turbine generator is considered as an interconnected system of the machine-side system and the gird-side system,and the small-signal model of it is established firstly.Secondly,according to the model and diagram of the system,the channels and influencing factors of the dynamic interaction between the machine-side and grid-side converters are exploited.Finally,the existence and impact of the dynamic interaction between the machine-side and grid-side systems are validated through study cases.