摘要：针对现有高温光纤式叶尖定时传感器最高耐温只到650℃,无法满足更高温度条件下燃气轮机叶片振动监测需求的问题,研究并设计一种采用主动冷却方式的高温光纤式叶尖定时传感器。为提高传感器的耐温性能,采用中空式的结构设计以及主动冷却的降温方式提高传感器探头的耐温性能。应用Ansys有限元分析软件进行热-流-固耦合分析,对传感器设计的可靠性进行理论论证。在此基础上,对设计的高温光纤式叶尖定时传感器进行高温试验验证。结果表明:试验结果与仿真结果具有良好的一致性,该传感器工作温度最高可达1300℃,满足大多数高温环境下燃气轮机叶片振动参数监测的要求。

摘要：With the development of power plants towards high power and intelligent operation direction,the vibrations or failures of blades,especially the last stage blades in steam turbines,happen more frequently due to the unstable operating conditions brought by flexible operation.A vibration measuring method for the shrouded blades of a steam turbine based on eddy current sensors with high frequency response is proposed,meeting the requirements of non-contact heath *** eddy current sensors produce the signals which are related to the area changing of every blade’s shroud resulting from the rotation of *** an improved blade tip timing(BTT)technique is proposed to detect the vibrations of shrouded blades by measuring the arrival time of each area changing signal.A structure of eddy current sensors is developed in steam turbines and an amplitude modulation/demodulation circuit is designed to improve the response bandwidth up to 250 *** tests for the last stage blades of a steam turbine were carried out and the results validate the efficiency of the improved BTT technique and the high frequency response of the eddy current sensors presented.

摘要：针对汽轮机自锁叶片叶尖间隙的测量要求,提出一种改进的叶尖间隙测量方法,设计了一种适用于汽轮机工作环境的电涡流传感器及其信号处理方法。当自锁叶片旋转时,其围带及锁紧处会交替经过电涡流传感器探头,产生电压信号,通过检测电压信号,应用相应信号处理方法进行处理以获取叶尖间隙。在高速动平衡室使用某型汽轮机末级长叶片进行实验对方法进行验证,实验结果表明所述改进的叶尖间隙测量方法在汽轮机自锁叶片的叶尖间隙测量中是可行的,可测量转速达到3000 r/min,整圈叶片个数达60个的自锁叶片叶尖间隙。

摘要：针对压电换能器谐振频率漂移的问题,基于双路电流反馈与二分法扫频研制了一款基于频率跟踪的超声驱动电源。根据压电换能器的电路模型,分析了双路电流有效值及其相位差与超声驱动电源串联谐振频率间的关系;利用双路电流信号进行频率反馈控制,在匹配失调、负载变化的情况下仍可精确跟踪换能器的串联谐振频率;利用微处理器实时控制开关电容滤波器的中心频率,实现恒带宽的跟踪滤波器;利用二分法扫频完成对压电换能器串联谐振频率的快速跟踪,完成了原理样机的研制,并进行了相应实验。实验结果表明,所设计的超声驱动电源适应能力强、频率跟踪精度高、跟踪速度快,可在100ms内完成频率的跟踪和锁定,频率跟踪精度可达20Hz。

摘要：针对极近距离下传统无线供电方式谐振频率和电压增益受线圈气隙影响较大的问题,此处提出了基于串联式LLC谐振电路拓扑形式的无线供电系统。通过建立电路模型研究其频率增益特性,提出调整控制信号与次级电流同相实现自动频率追踪,并分析推导了变压器实际损耗对调谐精度的影响及补偿方式。针对所述方法对电流过零点时刻信息的需求,提出一种简单、通用、低成本的光反馈电路。设计样机并进行测试和对比实验,结果表明:系统实现了自动调谐功能,在0.2~1mm的间距范围以及12 V供电0.4~0.8的品质因数范围下频率变化2%,电压变化1%,证明了所提方案的有效性。

摘要：The disguised covert detection method that imitates whale calls has received great attention in recent years because it can solve the traditional problem of the trade-off between long-range detection and covert ***,under strong reverberation conditions,traditional echo signal processing methods based on matched filtering will be greatly *** on this,a disguised sonar signal waveform design is proposed based on imitating whale calls and computationally efficient anti-reverberation echo signal processing ***,this article proposed a disguised sonar signal waveform design method based on imitating whale *** method uses linear frequency modulation(LFM)signals to replace LFM-like segments in real whale calls,and extracts the envelope of the real whale call’s LFM-like segment to modify the LFM ***,this article proposed an echo signal processing method of fractional Fourier transform(FrFT)based on target echo locating of synchronization *** method uses the synchronization signal to locate the target echo,and determines the step-size interval of the FrFT based on the information carried by the synchronization *** with the traditional FrFT,this method effectively reduces the amount of calculation and also improves the anti-reverberation ***,the excellent performance of the proposed method is verified by simulation results.

摘要：针对目前对汽轮机叶片运行状况难以检测现状,通过对叶片健康监测需求进行分析,设计并实现了基于嵌入式的汽轮机叶片健康监测系统。采用ARM和FPGA相结合的方案,使用了CAN和TCP/IP通讯协议,同时对汽轮机叶片的间隙、振动和温度参数进行实时采集分析和存储,并通过上位机进行实时状态显示,同时将数据存入数据库中。测试结果表明,该系统能实时、不间断地对汽轮机叶片进行监测;可以在1秒内快速、准确检测出故障信号并进行预警;具有良好的人机交互性。

摘要：正交分光成像系统在高频动态坐标测量中具有独特优势。针对其在高频测量条件下数据量大,光斑坐标难以实时提取的问题,提出了一种基于现场可编程门阵列(FPGA)的实时多光斑峰值位置亚像素定位算法。首先设计与光斑光强分布相近的模板,通过模板匹配解决了原始图像中因噪声导致的峰值抖动问题;其次对匹配后的图像进行阈值比较并生成窗口信号,对窗内像素进行高斯拟合,拟合中心作为光斑峰值亚像素坐标。计算中充分利用FPGA并行处理的特点,采用流水线设计实现了硬件加速。实验表明,该算法可实现对多光斑位置的实时提取,光斑重复定位极差小于0.1像素,标准差为0.014像素,分辨力达亚像素级别。

摘要：针对超声疲劳试验中20 kHz以上的高频振动幅值的测量问题,提出一种电容式高频振动幅值测量方法,并构建了基于该方法的测量系统。文中以振动信号处理为主线,设计基于调幅式的振动解调电路,实现传感器信号的高精度解调;设计频率自适应数字滤波器实现解调信号的动态滤波;设计基于Hilbert变换实现数字包络检波器完成振动信号幅值的精确求解。对基于此方法测量系统的精度和测量范围进行了实验验证,实验结果证明,此系统具有较高的精度和较大的测量范围,其精度优于0.3%F.S.,振幅测量范围最大可至100μm,动态频响超过20 kHz。

摘要：In order to achieve high precision measurement of inductance in a wide frequency range,a method of inductance measurement based on double-excitation auto-balancing bridge is *** this method,the direct digital synthesizer(DDS)as signal generator is used as the bridge excitation source,and the bridge is automatically balanced by adjusting and measuring the voltage *** standard resistors,the system can achieve high precision measurement of four-terminal pair inductors in the frequency range of *** at the low efficiency of bridge balancing,an iterative balancing algorithm based on the steepest descent method is *** order to suppress the interference caused by the initial phase change and non-integer periodic sampling,the high-precision measurement of the complex impedance of inductance is realized based on the all-phase fast Fourier transform(apFFT).Finally,the corresponding measurement system is built and the inductance measurement experiment is carried *** experimental results show that the relative error of the system for inductance measurement can be as low as 0.009%,and the optimal relative measurement uncertainty of the system can reach 9.89×10^(-4)compared with 5×10^(-5)of commercial impedance analyzer.