Research On Micro Rogowski Coil Sensor For Press-pack IGBT Chip

With the rapid development of the society,the demand for energy is increasing day by day.Flexible DC transmission has been widely developed with its more flexible and reliable transmission mode.In order to maintain the safe operation of the system,more stringent requirements are put forward for the controllable rectifiers(usually IGBT)which constitute the flexible converter.Compared with welded IGBT,The Press-Pack IGBT has a longer service life,a unique short-circuit failure mode,and high current carrying capacity.Generally,multiple chips of Press-Pack IGBT are connected in parallel to increase the PPI current level.However,due to the influence of the boss chip layout,it will inevitably make the current of each chip unequal and the internal chip current overshoot during the turn-on and turn-off,This will affect the reliability of the device.This thesis will design a micro PCB Rogowski Coil sensor for the monitoring and measurement of chip transient current.First of all,this thesis expounds the development status of high-power IGBT and current sensors at home and abroad,in which the advantages of Rogowski coil sensors are expounded in detail.Secondly,the working mechanism and dynamic characteristics of Rogowski Coil current sensors are analyzed in detail,mainly in the following aspects: First,the working principle of Rogowski Coil is analyzed.Second,the Rogowski Coil equivalent model is established,and two different transfer function formulas of concentrated parameter and distributed parameter are analyzed.Third,discuss the two working methods of selfintegral and external integral.Fourthly,the effects of different electromagnetic parameters and structural parameters of Rogowski Coil on the performance of Rogowski Coil system are analyzed with the help of matlab simulation.Thirdly,the coil error was analyzed from three aspects such as winding density.For the special structure of the Press-Pack IGBT,With the help of software such as AD and ANSYS,a single,small,thin,fishbone with return line,four-layer board and square PCB Rogowski Coil with a return line was designed from the aspects of coil size,wiring,and shape.Based on the Rogowski Coil,a PCB board integrated with four PCB coils was designed and processed to measure the current of multiple chips at the same time.Aiming at the characteristics of IGBT breaking current,a composite integrator consisting of coaxial cable,passive integration circuit,in-phase active integration circuit,high-pass filter circuit,and in-phase buffer amplifier circuit was designed by Pspice.Finally,with the help of an impedance analyzer,the consistency of the PCB coil parameters was verified from both simulation and experiment;the feasibility of the integrator was verified by Pspice overall circuit simulation;the lightning surge surge signal experiment and double pulse test experiment platform were built.The experiment verified the differential characteristics of the PCB coil,and achieved the measurement of the current of the Press-Pack IGBT chip.The current obtained by software integration is basically consistent with the commercial sensor,which further proves that the PCB Rogowski Coil sensor designed in this thesis fully meets the Press-Pack IGBT chip current measurement.Compared with commercial sensors,it has higher sensitivity,wider measurement range,lower cost,more convenient measurement and easier integration.