Development of Battery-Less Wireless Current Sensor Node Utilizing Charging Time of Capacitors with Wide Measurement Range

We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.

基于CC2530的电流及温度监测系统的设计与实现

为了实时监控分布广、数量多、工作时间长和工作电流大的设备的工作情况,设计了由线性电流传感器ACS712、温度传感器DS18B20以及片上系统CC2530组成的无线传感器节点,利用ZigBee技术组建的电流及温度无线监测系统.实验表明:系统具有检测精度高,可靠性高,成本低,使用方便等特点,可应用于工业环境的电流及温度在线监测领域.

无线传感器节点模块级故障诊断方法的研究

为了快速检测出无线传感器网络(WSNs)节点故障的位置和诊断产生故障的原因,设计了一种WSNs节点故障在线状态监测器,分别对WSNs节点中的供能模块、传感器模块,处理器模块和无线通信模块的工作状态进行在线监测。提出了一种基于无线通信模块电流模型的故障诊断方法,利用BP神经网络对无线通信模块不同状态下的故障诊断参数进行动态调节。经过对节点实际运行数据的采集、分析、建模与实验,结果表明:当WSNs节点出现故障时,诊断系统能够自动定位WSNs节点中故障发生位置,并提示故障产生的原因。此外,本故障诊断方法不需要额外辅助节点或测试整条无线连通路径,就能检出无线通信模块的多种类型故障,且故障诊断结果精度较高。

基于无线传感器网络的机电设备复合故障定位方法

为实现更加迅速、误差更小、覆盖率更高的机电设备复合故障定位,引入无线传感器技术,优化设计机电设备复合故障定位方法。设计无线传感器数据采集网络,无线传感器数据采集网络由协调器节点、路由节点、电流传感器节点等构成,基于无线传感器网络完成机电设备复合故障数据采集。在此基础上,将采集的复合故障数据借助相模变换、小波能量熵进行预处理,相模变换能够使电压解耦或相电流成为互相独立的模态分量,小波能量熵能够估计不同尺度的信号能量。根据虚警概率和传感器检测概率,设计机电设备复合故障定位算法,将复合故障定位问题转化为故障观测空间中实际观测向量的归类问题,实现机电设备复合故障定位。测试结果表明:设计方法的复合故障平均定位误差较低、平均定位覆盖面积较高、整体复合故障定位耗时较短。