Research On Detection Technology Of Rogowski Coil Pulse High Current

Current measurement is one of the important electrical measurement technology,current detection is divided into DC,AC,pulse current detection and so on.In recent years,with the development of science and technology,pulse current detection has been more and more widely used in the fields of national defense,energy and industry.Due to the complex frequency component of pulse current,high pulse peak value and large uncertainty of waveform,pulse current detection has many technical deficiencies and is a hot topic in the field of electrical measurement.At present,the current pulse detection equipment includes shunt,transformer,Hall element,optical fiber sensor,and Rogowski coil,etc.Due to its advantages of good linearity,wide response frequency range,little influence on the measured circuit,and not easy to saturation,Rogowski coil has been gradually paid attention to in practical engineering.Firstly,this paper investigates the current detection technology of Rogowski coil at home and abroad,and analyzes the problems existing in the current detection of large pulse current of Rogowski coil.Rogowski coil under ideal conditions of the output signal is proportional to stay current measurement size rate of change of voltage signal,however,because of the distributed capacitance between Rogowski coil turns,high signal frequency will be lead to output characteristic deviations from the ideal differential capacitance integral,moreover,at high frequency,the signal processing circuit of capacitor,resistor and inductor is deviating from the ideal device characteristics,This leads to the problem that the frequency range of detecting pulse current with Rogowski coil is not wide enough at the present stage,and it is often inaccurate in detecting high frequency and large current pulse.In this paper,the structural characteristics of the Rogowski coil are studied theoretically.Through the mathematical calculation of the structure of the Rogowski coil,combined with the electromagnetic theory,the internal resistance and mutual inductance coefficient of the Rogowski coil are deduced theoretically,and the measurement principle and theory of the Rogowski coil are improved.The time domain and complex frequency domain transfer functions are calculated theoretically,and the coil is divided into two working modes: low-frequency self-integration and highfrequency external integration.The mathematical models of the two working modes are established,and the common error sources and influences are analyzed,which provides a theoretical basis for the subsequent circuit simulation and design.This paper builds a circuit to simulate the Rogowski coil,tests the influence of internal resistance,self-induction,distributed capacitance and other parameters on the performance of the Rogowski coil,and designs a compound circuit structure of frequency selection network and integrator.Because the pulse current contains rich frequencies,the signal is divided into two channels through the frequency selection network,and the two channels of signals are respectively superimposed through the processing circuit of the response,so as to expand the frequency range.After the feasibility is verified by computer simulation,the actual hardware circuit is processed.Using the programmable power supply as the source to be measured,the experimental test verifies that the linearity of the designed Rogowski coil meets the expected requirements,and the current detection device can meet the expected requirements of 0.1ms ～ 1ms width pulse detection.