基于自由轴法的电感测量电路设计

Design of the circuit measuring inductance based on free-axis method

电感探针技术是一项检测金属腐蚀的新技术,通过测量电感探针中测试线圈在金属试片腐蚀前后的电感变化量来测量腐蚀速率。相比传统方法,具有响应速度快、灵敏度高、测量精度高、适用范围广、测量结果几乎不受温度影响等优点。电感的测量精度决定了电感探针腐蚀监测系统的测量精度。因此,电感的高精度测量对于电感探针腐蚀监测系统至关重要。设计的电感测量电路采用自由轴法进行电感测量。电路以STC89C52单片机作为微处理器,选用基于DDS技术的信号发生芯片AD9850产生所需的测试信号,利用阻抗串联分压原理及相敏检波原理,实现了对电感的精确测量,在电感探针腐蚀监测系统中具有较好的应用价值。

Inductance probe technology is a new method which is used to monitor metal corrosion.In this technology,the rate of metal corrosion is measured by measuring the inductance variation of testing coil in inductance probe before and after metal sample is corroded.Comparing with other traditional methods,the method has advantages such as fast response speed,high sensitivity,high accuracy,wide application range and measurement results are almost independent of temperature.The accuracy of measuring inductance determines the accuracy of the corrosion monitoring system using inductance probe.Therefore,measuring inductance accurately is essential to the corrosion monitoring system using inductance probe.Free-axis method is adopted to design the circuit measuring inductance in this paper.STC89C52RC microcontroller is used as microprocessors and the chip AD9850 based on DDS technology is used to generate the required testing signal.The voltage division principle of the series impedance and the principle of phase-sensitive detection are used to realize accurate measurement of inductance.The circuit has good application value in the corrosion monitoring system using inductance probe.