考虑一次调频死区的风电机组虚拟同步控制参数优化研究

Optimization of virtual synchronous control parameter for WTG considering dead zone of primary frequency regulation

风电机组基于虚拟同步发电机(VSG)控制参与系统频率支撑时,调频参数设置不当可能导致转速低于约束值或变流器功率超出限值,且现有研究较少计及风电机组一次调频死区对系统频率响应的影响。因此,本文提出一种考虑一次调频死区及调频物理约束边界的风电机组虚拟同步控制参数优化方法。首先,更为精细化地计及一次调频死区的建模,建立含VSG控制的风电机组系统全过程频率响应模型。其次,通过轨迹灵敏度分析方法研究风电机组调频参数发生变化对频率响应全过程动态轨迹影响的强弱程度,分析结果表明虚拟阻尼系数在调频过程中起关键作用。在此基础上,综合考虑风电机组的不同运行工况及系统频率动态响应过程,以转子转速约束和变流器容量限值为条件获得风电机组调频物理约束边界下虚拟阻尼系数优化值,充分利用了风电机组可用调频容量。最后,基于Matlab/Simulink仿真平台搭建系统仿真模型,仿真结果表明所提方法可充分发挥风电机组的频率调节能力,避免响应超出调频物理约束边界,有效提高了系统频率稳定性。

When wind turbine generator(WTG)participates in system frequency response based on virtual synchronous generator(VSG)control,improper parameter may cause the rotor speed to fall below the limit value or the converter power to exceed the limit value.Moreover,few existing studies consider the impact of the dead zone of primary frequency regulation for WTG on system frequency response.Therefore,this paper proposes an optimized method for VSG control parameter of WTG that considers the dead zone and the physical constraint boundary of primary frequency regulation.Firstly,the modeling of the dead zone is considered more refined,and the whole process frequency response model of the WTG controlled by VSG is established.Secondly,the influence degree of WTG frequency regulation parameters on the whole dynamic trajectory of frequency response is studied by trajectory sensitivity analysis.The results show that the virtual damping coefficient plays a key role.On this basis,considering the different operating conditions of the WTG and the frequency dynamic response process of the system,the optimal value of virtual damping coefficient under the physical constraint boundary is obtained by taking the rotor speed constraint and the converter capacity limit as the conditions,which makes full use of the available frequency regulation capacity of the WTG.Finally,the system simulation model is built based on Matlab/Simulink simulation platform.The simulation results show that the proposed method can fully utilize the frequency regulation ability,which can avoid responding beyond the physical constraint boundary of primary frequency regulation and effectively improve the frequency stability of the system.