燃爆环境下超声测距换能系统本安驱动机理及其电声阻抗匹配优化

The ultrasonic ranging system drives the transducer to complete the conversion of electrical energy to mechanical energy by the high-voltage pulse, and the conversion of mechanical energy to electrical energy is achieved by the electromechanical resonance. But in the state of short circuit, overload and switching, the inherent nonlinear storage of energy and release of energy can cause system to generate non-safe spark and energy, restrict its application in flammable and explosive environment. The exploration of the mechanism of intrinsically safe driving and the method of improvement of energy conversion efficiency for the ultrasonic energy conversion system is an important scientific problem which has to be solved for the application of the ultrasonic systems in flammable and explosive environment. Firstly, according the minimum ignition energy theory, the analysis on the non explosive intrinsically safe characteristics of the driving method is made. An electric circuit model for the numerical simulation and the analysis of attenuation of the driving ability is established, and the intrinsically safe driving mechanism of the energy conversion system is clarified. Secondly, the theoretical methods of the optimization of electrical and acoustic impedance matching to improve the energy conversion efficiency are determined. The mechanism of matching optimization based on the model of Multiple Criterion Decision Making (MCDM) is designed. The index optimization is carried out by the construction of a decision-making matrix. The improvement of the energy conversion efficiency is achieved from the aspect of the matching of transmissions of electric signal and mechanical wave, by the analysis of impedance matching and the fabrication of energy conversion element. The implementation of the project will provide a new energy conversion method for the intrinsically safe driving and its optimization of electrical acoustic impedance matching of the ultrasonic energy conversion system, as well as provide the reference for the safety design and application of other ultrasonic system in flammable and explosive environment.

超声测距系统通过高压脉冲驱动换能器完成电能向机械能的转换，并通过机电谐振实现机械能向电能的转换，但在短路、过载、换路等状态下，固有的非线性储能放能会导致系统产生非安全火花及能量，制约了其在燃爆环境中的应用。探索超声换能系统的本安驱动机理和换能效率提升方法会有助于系统在燃爆环境中的安全使用。首先，根据最小点燃能量理论对驱动方法进行非爆炸性本安特性分析，建立回路电气参数模型实现驱动能力的数值模拟和衰减分析，阐明换能系统本安驱动机理。其次，确定本安驱动下换能系统电声阻抗匹配优化提升能量转换效率的理论方法，设计基于多指标决策模型的匹配优化机制，构建决策属性矩阵实现指标优化，并通过阻抗匹配分析与换能元件制备，从电信号和机械波传输匹配方面实现能量转换效率的提升。本项目的实施将提供一种超声换能系统的本安驱动及其电声阻抗匹配优化的换能方法，也为其它超声系统在燃爆环境下的安全设计与应用提供借鉴。

随着煤矿生产自动化水平的逐步提升，适用于煤矿井下燃爆环境中的超声检测技术需求迫切。传统超声换能系统广泛使用的中周变压器有产生电火花的风险，不符合本安要求，而采用防爆结构会导致体积庞大、结构复杂等问题，无法安装使用。因此，超声换能系统本安化是解决这一问题的关键核心难题。.本项目开展了无变压器驱动的超声换能机理研究，利用最小点燃能量计算实现了对驱动电路的非爆炸性评价，研究了基于阻抗匹配原理的超声驱动方案，提高了能量转换效率。.围绕涉及的关键技术问题，设计了基于降压升压变换输出的本质安全超声驱动回路，研究了基于电压电流特性分析的超声驱动回路最小点燃能量抑制方法，提升了基于阻抗匹配网络优化的超声驱动回路能量效率，设计了基于双重过流过压保护功能的本质安全供电方案，同时将抗干扰能力较强的LIN总线用于超声换能系统，在此基础上，将具有本质安全特征的光纤传感技术用于超声信号检测，进一步扩展燃爆环境下超声检测的技术手段。.项目执行过程中，取得的主要成果有：撰写学术论文10篇，其中被SCI收录4篇，EI收录1篇，中文核心期刊论文5篇；申请国家发明专利3项，授权软件著作权6项；参加国内学术会议4次。.本项目的研究成功对进一步提高超声驱动与超声检测技术在燃爆环境中的安全性具有重要的理论意义和工程价值，此外，可为燃爆环境下的超声探伤、超声电机、超声清洗、超声雾化等各类超声系统的本安分析与设计提供新的解决思路与办法，为能源、化工、采矿、冶金等考虑燃爆要求的工业领域安全生产提供新的保障与支持。