| With the global climate and environmental problems becoming increasingly prominent,China has put forward the development goal of "carbon peaking,carbon neutrality",promoting the development of new energy power generation and electric vehicles is of great significance to achieve the "carbon neutrality".As a new generation of power semiconductor devices,the application of Si C MOSFET power modules in the main inverters and frequency converters of the above-mentioned places can increase the power density of the system,improve the efficiency of power conversion,and reduce energy loss.However,there are some problems in its application,Due to the faster switching frequency and speed,the oscillations and voltage and current overshot phenomena during the switching process of Si C MOSFET are significant,resulting in additional switching stress,leading to prominent electromagnetic interference problems;In addition,when short-circuit occurs,compared with Si-based semiconductor,the current density of Si C MOSFET is larger,the heat accumulation is faster,and the shortcircuit tolerance time is shorter,thus the short-circuit failure of Si C MOSFET is easier to occur.In view of the above two aspects,the main research contents of this paper are as follows:Firstly,the superior performance of Si C materials and the device research status of major manufacturers at home and abroad are introduced.Then the main working principle and electrical characteristics of Si C MOSFET modules are summarized.The switching process of Si C MOSFET is analyzed in detail by dividing into different stages,based on this,the influence of drive parameters on the switching process is verified by simulation and experiment.Besides,the appropriate range of driving parameters is given.Secondly,in order to solve the problem of oscillation and overshoot of voltage and current during the switching process of Si C MOSFET power modules,a drive circuit with auxiliary gate current control unit was proposed,which controls the charging and discharging speed of gate capacitor at different stages by detecting the drain voltage and current during the switching process.A complete digital driver was designed and fabricated by Altium Designer.Compared with the conventional active gate drive,the double-pulse experiment verifies that AGD has good oscillation and voltage and current overshoot suppression performance and switching loss performance.At the same time,the AGD drive circuit can improve the EMI performance during the device operation stage.Besides,the oscillation and overshoot suppression functions of AGD were verified under different voltages,currents and operating temperatures.Finally,the main influencing factors of HSF and FUL short-circuit characteristics are analyzed through simulation and experiment.By comparing and analyzing the main short-circuit detection and protection methods of Si C MOSFET,a desaturation detection scheme with high reliability and wide commercial application is selected to design and make the corresponding short-circuit protection drive circuit.Simulation and experiment show that the drive circuit can reliably detect and shut off HSF and FUL short circuits.In the experiment,an auxiliary grid current control unit is used to reduce the overvoltage spike when the short-circuit current of the Si C MOSFET power module is turned off.There are 98 pictures,7tables and 80 references in the paper. |
