Digital compensation method for high frequency current probes

Based on the steepest descent theory (Edmonson W, Srinivasan K, Wang C and Principe J 1997 IEEE Trans. Circuits Syst. 45 379-84, Neil E and Mian O N 1992 IEEE Trans. Neural Netw. 3 308-14) and the original response curve of a current probe used for power system electromagnetic compatibility measurement, an accurate analogue model has been built for the probe, with a maximum error of 5.2%. Before application the analogue model needs to be discretized in the z domain, however the digital model gives a steeper frequency response than the analogue one. To compensate for this effect, another digital band-pass filter was attached to the above model, and its parameters were obtained by computer simulation. The compensated digital model presented a maximum error of 5.8% compared with the probe's response curve. The digital modelling and compensating strategy can feasibly expand the frequency band over which the probe is useful for measurement applications.