自供电的电流传感器电路设计

Circuit Design of Self-powered Current Sensor

电流互感器(CT)具有电流传感器和供电变压器两种工作模式。理论分析电流互感器在这两种工作状态下的等效电路,推导在供电模式获取的最大输出功率及并联谐振电容对输出功率的影响。在此基础上,提出一种自供电的电流传感器电路,通过电流互感器获取电能给电流测量电路供电。该电路采用一个供电、测量切换电路,通过两种工作模式的平稳转换,从而实现自供电检测电缆电流的功能,最后试验验证了该电路。

Current transformer （CT） has two working modes： current sensor and power supply transformer. The equiva lent circuit of the current transformer in these two working states is analyzed theoretically, and the maximum output pow er obtained in the power supply mode and the influence of the parallel resonant capacitor on the output power is derived. On the basis of this, a self-powered current sensor circuit is proposed, which can supply power to the current measure ment circuit by the current transformer. The circuit adopts a power supply and measurement switching circuit, and reali zes smooth switching of the two working modes, so as to realize the function of self-powered detection of cable current. Finally, the circuit is verified by experiments.