铁磁管道用极低频磁发射机的逆向优化设计  

Reverse optimization design of ELF magnetic transmitter for ferromagnetic pipeline

作　　者：蔡雄[1] 郭静波[1] 胡铁华[2] 张志文[2] 陈水平[3] 

机构地区：[1]清华大学电力系统国家重点实验室,北京100084 [2]机械科学研究总院,北京100044 [3]江西省电力公司,南昌330077

出　　处：《仪器仪表学报》2014年第3期634-641,共8页Chinese Journal of Scientific Instrument

基　　金：清华大学自主研究(2012THZ07122)资助项目

摘　　要：极低频磁信号对金属管道、岩石等高磁导率介质穿透力极强,在石油、天然气管道检测工程中常作为移动机器人跟踪与定位用的磁场源。在管道移动机器人跟踪与定位实践中,不同类型的管道,其尺寸、壁厚等有较大差异且管道埋深也不尽相同,这就需要不同功率的极低频磁发射机。将管道环境下极低频磁信号的传播规律和信号发射接收工程应用相结合,提出一整套极低频磁发射机的逆向优化设计方法。首先,根据极低频信号接收机中所用检测算法的检测概率与信噪比之间的关系得到某一检测概率下的接收机需要的最低信噪比,继而得到接收机前端的最小磁感应强度。然后以接收机前端的最小磁感应强度为基点,反推管道内极低频磁发射机需要产生的最小磁感应强度,由此设计出满足磁场与几何尺寸约束的发射机线圈结构与电路拓扑。由该方法得出的设计结果,既能满足接收机对磁感应强度的要求,又能保证发射机供电电源的使用寿命远远超过要求的连续工作时长;同时当工况参数在一定范围内变化时,接收机前端的磁感应强度仍满足以高检测概率检测到极低频信号的要求。Extremely low frequency （ELF） magnetic signal is usually used as the magnetic field source for tracking and location of mobile robots in oil and gas pipeline inspection,because the ELF signal is able to penetrate high permeability materials,such as metal pipeline,soil and rock.The diameter,thickness and buried depth of the pipelines vary with the circumstances in the tracking and locating engineering practice of inspection robots,which requires different types of ELF magnetic transmitters with different transmitting power.In this paper,the propagation rules of ELF magnetic signal and the engineering application of signal transmission and reception in the pipeline environment are combined together,and then a complete reverse optimal design method of the ELF magnetic transmitter is proposed.Firstly,according to the relationship between detection probability of the algorithm used in the ELF signal receiver and the corresponding peak SNR,the lowest peak SNR required by the receiver under a certain detection probability is derived,and then the minimal magnetic flux density at the front end of the receiver is determined.Secondly,the required minimal source magnetic flux density of the ELF magnetic transmitter in the pipeline is calculated reversely based on the minimal magnetic flux density at the front end of the receiver.Thirdly,the ferromagnetic core coil structure and circuit topology of the transmitter are designed under the constraints of the source magnetic flux density and the geometric dimension of the transmitter.The design result obtained with the proposed method not only meets the magnetic flux density requirement of the receiver,but also guarantees that the service life of the power supply for the transmitter greatly exceeds the required working duration in the pipelines.At the same time,even when the related parameters in practical circumstance change,the magnetic flux density at the front end of the receiver still meets the requirement of detecting ELF signal with high detection probability.

关 键 词：管道检测 极低频信号检测 磁发射机 逆向设计 峰值信噪比 

分 类 号：TP274[自动化与计算机技术—检测技术与自动化装置] TN911.23[自动化与计算机技术—控制科学与工程]