基于罗氏线圈的室内电源负载电流检测电路设计

Rogowski Coil based Current Measuring Circuit Design for Indoor Power Supply Loads

通过分析罗氏线圈的测量原理,设计了一款作为电流互感器的罗氏线圈及其信号调理电路,用以实时测量室内电源的负载电流。该罗氏线圈采用塑料圆环作骨架和漆包铜线为绕线,信号调理电路采用由新型低噪声的OPA 211构成的二级精密运算放大电路,其中,第一级运算放大电路将罗氏线圈感应出来的毫伏级电压信号加以放大,第二级运算放大电路采用钽电容作为积分元件,用以还原被测电流和对产生的干扰噪声信号进行滤波。实验结果表明:该罗氏线圈及其信号调理电路具有线性度好、测量精度高、制造成本低等优点,满足0.5级电流互感器工频电流测量要求,具有工程应用意义。

By analyzing the measuring principle of Rogowski coil, a new current transducer with the Rogowski coil is proposed for on-line measuring indoor power supply load currents. The Rogowski coil is designed with plastic ring and enamel-insulated copper wire, which are used as its framework and winding wire, respectively, and the signal processing circuit is designed with two precise operating amplifiers by employing OPA 211 with low noise. Amongst, the first amplifier serves to amplify the inducted millivolt signal form the Rogowski coil, while the second amplifier serves to restore the measured current signal and filter the yielded interrupt noise signal. The experiment results show that the proposed Rogowski coil and its signal processing circuit has merits of good linearity, high measuring precision and low manufacturing cost, which meets the measuring requirement of industry frequency current transducer with 0.5 grade and has important engineering application value.