海上风电机雷达回波及其微多普勒特征  

Radar echoes simulation and micro-Doppler characterization of offshore wind turbine

作　　者：尚智宇 唐波[1] 张龙斌 谢黄海 李逸峰 Shang Zhiyu;Tang Bo;Zhang Longbin;Xie Huanghai;Li Yifeng(College of Electrical Engineering&New Energy,China Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡大学电气与新能源学院,宜昌443002

出　　处：《电子测量技术》2023年第11期49-56,共8页Electronic Measurement Technology

基　　金：国家自然科学基金(51977121);清华大学国家重点实验室开放基金(SKLD21KZ03)项目资助。

摘　　要：精确模拟海上风电机雷达回波并提取其微多普勒特征,是解决海上风电场对邻近雷达台站无源干扰的关键问题。由于现有算法将风电机所处的海面背景直接以平面良导体等效而过于简单,且传统的等间距散射点模型无法表征风电机叶片的三维异形曲面特征。为此,在回波求解时引入粗糙海面前向复反射系数,同时结合风电机的三维散射点等效模型,提出了基于时域回波电场的海上风电机雷达回波数值模拟算法。根据矩量法中RWG函数离散电场方程的思想,建立风电机三维散射点等效模型。考虑到电磁波作用在海面时的畸变效应,利用粗糙海面前向复反射系数推导出了时域回波电场求解公式,并获取了海上风电机雷达回波的模拟结果。最后,将风电机海面背景下的回波微多普勒特征与自由空间下的进行对比,证明海面背景不可忽略。进一步采用控制单一变量的方法分析了微多普勒频移的海况响应特性,即浪高的均方根与多普勒频移呈负相关。这也为后续海上风电机回波的识别与滤除提供理论参考。It is key issue to accurately simulate the radar echoes of offshore wind turbine and extract micro-Doppler features,and they can solve the reradiation interference of offshore wind farms to neighboring radar stations.Aiming at the problem that the existing algorithms treat directly the sea surface background of wind turbine as a planar good conductor and are too simple.In the meanwhile,the traditional equally spaced scattering point model cannot characterize the complex surface features of the wind turbine blade.Therefore,we introduce a multipath model with a forward complex reflecting coefficient model of rough sea surfaces in radar echoes simulation,also build 3-D scattering point equivalent model of wind turbines.So,a numerical simulation algorithm for radar echoes of offshore wind turbine based on time domain echo electric field is proposed.According to the though of discrete electric field equation of RWG function in the method of MOM,we establish a 3-D scattering point equivalent model of wind turbine.Considering the distortion effect when the electromagnetic wave acts on the sea surface,the time domain return electric field solution equation under a forward complex reflecting coefficient model of rough sea surfaces is derived.We perform vector superposition short-time Fourier variation about radar echoes,and obtain the simulation results of the radar echoes of the offshore wind turbine.By comparing simulation results and experimental results of the scaled-down model,it verifies the correctness of our algorithm.Finally,the micro-Doppler characteristics of the wind turbine echoes under the sea surface background are analyzed in comparison with those under free space,and it prove that the sea surface background cannot be neglected.The influence of sea state about micro-Doppler shift are further analyzed by controlling a single variable.It is,the root mean square of the wave height is negatively correlated with the Doppler shift.These results also provide theoretical reference for the subsequent identification

关 键 词：无源干扰 海上风电机 三维散射点 粗糙海面前向复反射系数 回波模拟 微多普勒特征 

分 类 号：TM2[一般工业技术—材料科学与工程]