基于端口频域特性的直驱风电机组控制器“黑/灰箱”辨识

Controller“Black/grey Box”Identification of Direct-Drive Wind Turbine Generator Based on Port Frequency-Domain Characteristics

为解决风电变流器控制器“黑/灰箱”化导致的建模难题,提出了一种基于端口测量阻抗的直驱风电机组控制器“黑/灰箱”辨识方法。首先,推导和验证了不同控制方式下机侧变流器直流端口和网侧变流器交流端口的解析阻抗模型;其次,分析了直流端口阻抗和交流端口阻抗的参数灵敏度,论证了控制参数的可辨识性,并通过阻抗的参数灵敏度提取了不同控制方式下直流端口阻抗的特征。在此基础上,提出了基于端口阻抗特征匹配的直驱风电机组“黑箱”控制方式辨识方法;进一步地,提出了一种基于端口测量阻抗的直驱风电机组“灰箱”控制参数辨识方法,即利用阻尼最小二乘算法使端口实测阻抗与理论阻抗在各个频率点处差值的平方和最小,可实现变流器所有控制参数的准确辨识。最后,通过算例验证了所提方法的有效性。

In this paper,a controller“black/grey box”identification method for a direct-drive wind turbine generator(WTG)based on port measured impedances is proposed to overcome the modeling difficulties caused by the control“black/grey box”problem of wind power converters.First,the analytical impedance models of the DC port of the machine-side converter and the AC port of the grid-side converter of a permanent magnet synchronous generator(PMSG)-based WTG are derived and validated under different control modes.Second,the parameter sensitivities of the DC and AC port impedances are analyzed to demonstrate the identifiability of the controller parameters,and the features of the DC port impedance under different control modes are extracted based on the parameter sensitivity.On this basis,a“black box”control mode identification method is proposed for a PMSG-based WTG based on frequency-domain impedance feature matching.Further,a“grey box”control parameters identification method,in which all control parameters are accurately identified by minimizing the sum of squares of the differences between the measured impedance and the theoretical impedance over the studied frequency range based on the damped least squares algorithm,is proposed for a PMSG-based WTG based on frequency-domain impedance characteristic consistency.Finally,the effectiveness of the proposed method is verified through a case study.This work is supported by National Natural Science Foundation of China(No.52277195)and North China Electric Power Research Institute Co.,Ltd.(No.KJZ2022056).