Design of integral circuit for Rogowski coil

In order to truly measure the steady and transient currents,an integral circuit for Rogowski coil is designed based on the integrator analysis,which takes the advantage of serial voltage negative-feedback amplifier with large input impedance to integrate the signal and ground inputs respectively and combines with the principle of subtracter to carry out dual-stage subtraction for implementing the ideal integration without zero drift. Simulation is carried out under Simulink environment for operational ampli-fier voltage offset,noise interference,etc. Comparison of the transient current tracking effect between the Rogowski coil with integrator of parallel voltage negative-feedback amplifier and that of proposed serial one show that,the latter truly reflects the steady and transient currents and effectively suppresses the interference of integrator zero drift with the sensor.