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提出一种新型光电式电流传感器。利用电流取样电阻将被测电流转换为电压,并利用场效应管(FET)的转移特性和发光二极管(LED)将被测电流信号转换为光强度信号,再将光信号由塑料光纤(POF)传输到光电探测器(PD),可以实现直流电流(DC)、方波脉冲电流(PC)以及工频交流电流(AC)的光学传感。综合利用FET的转移特性和PD的开路电压,并合理选择FET的静态工作点,可以实现DC的线性传感。在0.03～17.00A范围内,DC测量的非线性误差低于0.44%;方波脉冲电流响应的延迟时间约为160ns。本文提出的传感器具有响应速度快、结构简单、成本低和可实现绝缘测量等优点。
A new photoelectric current sensor is proposed. A current sampling resistor is used to convert the measured current into a voltage. The current signal is converted into a light intensity signal by using a transfer characteristic of a FET and a light emitting diode (LED), and the optical signal is converted from a plastic optical fiber (POF) To the photodetector (PD) for optical sensing of direct current (DC), square wave pulse current (PC), and commercial alternating current (AC). Utilizing the transfer characteristic of FET and the open circuit voltage of PD synthetically, and choosing the static working point of FET reasonably, can realize the linear sensing of DC. In the range of 0.03 ~ 17.00A, the nonlinearity error of DC measurement is less than 0.44%. The delay time of square wave pulse current response is about 160ns. The sensor proposed in this paper has the advantages of fast response, simple structure, low cost and insulation measurement.