Study On The Input-output Characteristic Of The Double-loop Magnetic Detector For DC Current Measurement

The precise measurement of the heavy dc is a main technology for energy saving.The dc comparator plays an important role in the measurement of heavy dc among kinds of measuring methods.Owning to the complicated environment of industrial site,the normal operation of magnetic modulator is often disturbed by electromagnetic interference.For improving the property of interference rejection,the single-channel magnetic modulator is changed to multi-channel magnetic modulator,however,the channel-closing problem caused by the false balance points in the input-output characteristic of the magnetic modulator often occurs in application.Therefore,the double-loop magnetic detector is designed,however,the results indicate the input-output characteristic is worse than expectation.The efficient ways to improve the input-output characteristic of the double-loop magnetic detector are studied deeply in this paper: in Chapter 2,the simulation model of the double-loop detector is established according to the operation principle;In Chapter 3,the influence of excitation voltage is proposed in principle,improving the input-output characteristic by changing the excitation voltage is analyzed based on the simulation results;In Chapter 4,the simulation models of three kinds of operation mode of the magnetic amplification loop are established,the influence of some factors to the input-output characteristic are analyzed,such as voltage,excitation waveform,reactance,sampling resister.Some approaches improving the input-output characteristic are presented.In Chapter 5,experiments are carried out on the prototype and compared with the simulation results,several effective methods to improve the input-output characteristic are proposed,which is meaningful to the broader application of the double-loop magnetic detector.