低功耗差分谐振式mA级DC电流传感器

A differential resonantDC/mA current sensor with low power consumption

利用磁致伸缩材料铁镓与双端固定石英音叉谐振器复合的结构,提出了一种数字频率输出的低功耗差分谐振式电流传感器。磁致伸缩材料作为一次敏感单元,在载流导线产生的磁场作用下产生磁致伸缩应力,石英音叉谐振器作为二次敏感单元,实现力-频率转换。采用螺旋线圈进行电流-磁场转换,2个磁敏感单元的差分传感结构在实现力-频率转换系数倍增的同时,能够抑制温度漂移的影响,大大增加了传感器的灵敏度。利用异或门混频调理电路对2个敏感单元的输出取差频,制备了差分谐振式电流传感器并进行了实验,结果表明:传感电路功耗为1.12 mW,传感器的灵敏度为25.2 Hz/A且能够分辨出5 mA的电流变化。

A low-power differential resonant DC/mA current sensor with digital frequency output is proposed based on the composite structure of magnetostrictive material fega and double-ended quartz crystal tuning fork resonator(DETF).As a primary sensing unit,magnetostrictive material generates magnetostrictive stress under the action of a magnetic field generated by a current-carrying conductor,the quartz crystal tuning fork resonator acts as a secondary sensitive unit to achieve force-frequency conversion.Solenoid coil is used for current-magnetic field conversion.The differential structure of two magnetic sensitive units can reduce the influence of temperature drift while doubling the force-frequency conversion coefficient.The sensitivity of the sensor is greatly increased.XOR gate mixing conditioning circuit is employed to take the difference frequency of the outputs of two sensitive units.A differential resonant current sensor is prepared and tested.The results show that the sensing circuit has a power consumption of 1.12 mW.The sensitivity of the sensor is 25.2 Hz/A and the sensor can distinguish a current change of 5mA.