数字闭环光纤电流传感器暂态特性仿真研究

数字闭环光纤电流传感器暂态特性主要包含频率响应与阶跃响应，对于电力系统的继电保护控制、故障录波等应用领域至关重要。在工程应用中，传统的测试方法由于其测试系统复杂、测试电流信号小等问题，不利于评估光纤电流传感器的暂态特性。利用数字闭环光纤电流传感器的闭环控制机理，提出一种在数字闭环光纤电流传感器反馈回路中添加相位调制激励的方法。首先，分析数字闭环光纤电流传感器的相位调制原理，通过建立数学模型验证相位调制激励的等效性；其次，根据数字闭环光纤电流传感器闭环控制算法，提出频率响应与阶跃响应的调制激励产生方法；最后，利用现有数字闭环光纤电流传感器产品平台完成频率响应与阶跃响应的仿真与测试。结果表明:采用相位调制激励的仿真数据与试验数据最大误差为0.12%，该调制激励方法不需要搭建复杂的测试系统，在现有硬件平台中即可实现不同电流信号的仿真测试。

Simulation research of the transient characteristics of a digital closed-loop fiber optic current sensor

Transient characteristics of digital closed-loop fiber optic current sensors (FOCSs) include the frequency response and step response which are important indexs in the industrial areas such as power system relay protection and fault recording. In engineering applications, due to the complexity of the test system and the poor accuracy of a small current signal, it is not conducive to evaluating the transient characteristics of an FOCS in a traditional way. According to the closed-loop control mechanism of a digital closed-loop optical fiber current sensor, a new method of adding phase modulation excitation to the feedback loop of a digital closed-loop FOCS was researched. First, the phase modulation principle of the digital closed-loop of FOCS was analysed, and a mathematical model was established to calculate and verify the equivalence of the phase modulation excitation; Second, based on the closed-loop control algorithm of the FOCS, the frequency response and step response modulation excitation generation method were proposed; Finally, use the existing digital closed-loop FOCS product platform was used to complete the simulation and test of frequency response and step response. The results show that the maximum error between simulation data and test data is 0.12%. The modulation excitation method can realize different current simulation tests of frequency response and step response on the existing hardware platform without building a complex test system.