Research of Accurate Digital Integrator for Rogowski Coil Current Transformer

In this paper, the integral precision and the DC drift problem in the digital integrator for the electronic current transformer based on Rogowski coil are studied. The related algorithms such as the integral algorithm and characteristics of DC offset problems are studied in depth. Based on these, a new digital integration algorithm is proposed by adding a delay factor α, increasing the sampling frequency, etc. A new data structure is designed by adding DC feedback, adding dual channel, etc. The simulation model built in MATLAB proves the good effect of the two aspects of the design. Compared with conventional integrators, the new digital integrator with the improved algorithm can obtain frequency responses closer to those of ideal integrator. The new data structure can effectively overcome the DC offset problems in the electronic current transformer. Further simulation results show that the designed digital integration algorithm has high accuracy, the absolute error of phase response does not exceed 1°, and the absolute error of magnitude response does not exceed 10
^-3
(dB). The new data processing structure can completely solve the DC drift problem after about 7 cycles.