Rogowski线圈数字积分器的直流误差消除方法研究

Research on DC error elimination method of Rogowski coil digital integrator

积分器是Rogowski线圈电子式电流互感器的重要组成部分,而积分器的精度受放大采样模拟电路中产生的直流误差的影响。文章对几种常用的直流误差消除方法进行分析,提出了一种镜像法,用一对参数相同的装置对一对等幅反相的信号进行采样从而对直流误差进行补偿。软件仿真和硬件测试的结果表明该方法在包含次谐波的电流和故障暂态电流的测量中,仅消除了模拟电路中的直流误差而最大程度地保证了被积信号的完整性,从而达到更高的积分精度。

Integrator is an important part of Rogowski coil electronic current transformer,but the accuracy of integrator is influenced by the DC error caused by amplification sampling analog circuits. This paper analyzes some methods which are usually used in eliminating DC error and puts forward a mirroring method which means to sample a pair of mirroring analog signal by a pair of the same ADCs. The simulation and hardware test result show that during the measurement of secondary harmonic and transient current,only the DC error is eliminated and the signal which is to be integrated is mostly left complete. As a result,a higher integration accuracy is reached.