基于双源自动平衡电桥的高精度电感测量装置设计

Design of High Precision Inductance Measurement Device Based on Dual-source Automatic Balanced Bridge

为实现电感的高精度、高效率、宽范围测量,搭建了一套低失真度、低噪声交流自动平衡电桥装置。该装置能够自动调平电桥并测试电桥各部分电压比例,从而计算得到电感值。利用数字相敏检波算法(DPSD)和拟牛顿迭代法可准确地完成电桥自动调平过程,采用高速数据采集卡组成同步采样系统提高电压比例测量部分的准确度,拓宽测量范围。在100,1000,10000 Hz等频率下,对10μH^10 H范围内的电感进行测量。实验证明,该装置在一定时间内测量相对不确定度为5×10^-6,准确度指标与阻抗分析仪对比,一致性好。

A high precision inductance measuring device based on a dual-source automatic balanced bridge is built in order to achieve high precision,high efficiency and wide range inductance measurement. The device automatically adjusts the bridge to balance and measures the ratio of voltage across the bridge so as to calculate the inductance. Digital phase sensitive detection( DPSD) and parsimonious Newtonian iteration are applied to ensure that the balancing point can be found efficiently and accurately. A sampling system based on high-speed digitizers can increase the precision and range of measurement. At typical frequencies including 100,1000 and 10000 Hz,inductances in the range of 10 μH ~ 10 H were measured by this device. The device can achieve a measurement stability of 5 × 10-6,and its accuracy is consistent with Impedance Analyzer Agilent E4980,which is experimentally verified.