管道超声内检测发射电路设计

Design of Ultrasonic Transmitting Circuit for in-line Inspection of Pipeline

在深入分析超声检测发射电路的基础上,设计了基于RLC串联谐振的发射电路,电路以场效应管为开关元件,电感储能形成高频、高压脉冲,建立了发射电路理论模型,分析了电路参数对高压窄脉冲的影响,理论计算产生的宽频高压脉冲激励信号与实验测量结果一致。该电路不需要提供直流高电压,只需要5V单电源供电,就可稳定获得宽度小于1μs,幅度大于400V,且无余振的高压窄脉冲。电路具有结构简单、体积小、不需要直流高压、功耗低、易于集成等特点,满足管道超声内检测的要求。

In response to the need of in-line inspection of pipelines, a transmitting circuit based on the RLC series resonance was designed following the in-depth analysis of ultrasonic transmitting circuits. This circuit adopted field effect transistor as the switch device with stored energy inductance generating high frequency and high voltage pulse. The theoretical model for transmitting circuit was developed and the effect of parameters of circuit on high voltage narrow pulse was analyzed. The theoretical calculation result of broadband high voltage pulse excitation signal is consistent with that of experimental measurement. This circuit is only supplied by 5 V single power source to obtain fluctuation-free high voltage narrow pulse with width to be narrower than 1 〉s and the amplitude to be more than 400 V rather than DC high voltage. This circuit features simple structure, small size, low power consumption, easy integration and without DC high voltage, which is suitable for in-line detection of pipeline corrosion.