测量低频大电流的自积分罗氏线圈设计

Self-integrated Rogowski coil for low-frequency high current measurement

为测量电容储能脉冲功率源模块电流,设计了磁芯式自积分罗氏线圈。给出了磁芯的选择方法,分析了磁芯饱和问题。解决饱和问题的方法是使用饱和磁感应强度较大的材料,对测量线圈施加去磁磁场,以及等效减小线圈的励磁电流。分析表明:通过增大磁芯直径和截面积,选取线径合适的导线多层绕制的方法来增大线圈自感与电阻比值,可以有效提高线圈的测量幅值范围。使用设计的线圈实测了脉冲功率源模块电流,通过改变模块的充电电压,可以得到线圈出现饱和时对应的电流值。实验结果与理论分析相符合。对于脉冲功率源模块的ms量级脉冲电流信号,改进后的自积分线圈测量范围可以超过50kA。

A self-integrated Rogowski coil has been designed to measure the current of the capacitive pulse power supply module. The waveform of the primary Rogowski coil output will distort because of the saturation of the ferromagnetic core in the coil under large current. The way to solve the problem is to use ferromagnetic materials of large saturated magnetic field strength,and to add inverse magnetic field on the Rogowski coil or reduce the excitated current equivalently. The measurement range can be enhanced with increasing the diameter and cross section area of the core for given ferromagnetic material. To increase the ratio of the self-inductance to the resistance of the coil is another way which can be achieved by winding the insulated wire in multiple layers. The current for core saturation was obtained by measuring the discharge current of the module under different charge voltages. The experiment verifies the analysis result. The measurement range of this improved Rogowski coil can exceed 50 kA for the millisecond scale current of the pulse power supply module.