Research On Integrated PCB Rogowski Coil For Press-Pack IGBT Device

Flexible DC transmission is an important way to build the energy Internet,which can solve the problem of unbalanced energy production and consumption in China.The Press-Pack IGBT device is the core device of flexible DC transmission converter valve.Due to the small area and low current carrying capacity of a single Press-Pack IGBT chip,in order to improve the transmission capacity of flexible DC transmission,multiple Press-Pack IGBT chips need to be connected in parallel.However,due to the difference in the electrical parameters of the parallel chips,the phenomenon of uneven current and current overshoot appears in the switching process of IGBT chips.In order to study the parallel current sharing of the Press-Pack IGBT device,it is of great significance to design a micro current sensor to detect the current of the parallel chip inside the pressed IGBT device in real time.In this thesis,the development history of high-power IGBT technology and the research status of current measurement technology are investigated and analyzed,and the Rogowski coil which is most suitable for the current measurement of Press-Pack IGBT devices is emphatically described.It is clear that the research content of this thesis is to design an integrated PCB Rogowski coil for the measurement of internal chip current of the Press-Pack IGBT devicesSecondly,the working mechanism and two working modes of Rogowski coil are analyzed,The influence of structure parameters and electrical parameters of Rogowski coil on its dynamic performance is analyzed by MATLAB simulation;This thesis studies the three factors that affect the measurement error of Rogowski coil,such as the measured conductor deviation,magnetic field interference and electric field interference,and puts forward the suppression measures.Then,according to the spectrum analysis of IGBT collector current and the structural characteristics of the Press-Pack IGBT device,the coil size,wiring,shape and shielding scheme are designed by using Altium designer.Finally,a PCB integrated with six square Rogowski coils is developed to realize the real-time measurement of the internal parallel chips of the Press-Pack IGBT device.The electromagnetic parameters of PCB Rogowski coils with and without shielding layer are measured by Q3 D simulation and impedance analyzer.Because the output voltage of Rogowski coil head is proportional to the change rate of the measured current,the current measured is restored by connecting the integrator later.In the design part of integrator,a composite integrator combining passive integration with active integration is built as the subsequent integration link of Rogowski coil head.The effectiveness of the composite integrator is verified by AC scan analysis,periodic signal simulation and double pulse simulation.Finally,the differential characteristics of PCB Rogowski coil are verified by periodic signal test;The shielding effect of grounding metal shielding layer on electric field noise is verified by shielding effect experiment;Through the double pulse test,the PCB Rogowski coil output voltage after integration is compared with the CWT UM 06 Rogowski coil of PEM company,which verifies the effectiveness of the PCB Rogowski coil designed in this thesis;The integrated PCB Rogowski coil is applied to measure the current of the parallel chip in the Press-Pack IGBT device,which provides a reference for the study of the parallel current sharing of the Press-Pack IGBT device.