A current-sharing optimization design method for multi-parallel switching devices based on finite element simulation

Abstract

The invention relates to the parallel current sharing problem of multi-device high-power MOS transistors, and proposes a multi-parallel switching device current sharing optimization design method based on finite element simulation. The multi-parallel switch devices include: a drive module, a first switch tube device, a second switch tube device, ..., an nth switch tube device. Manually set the length of the wiring between the drive module and the switching device, and design through the Altium Designer software according to the structural symmetry principle between the first switching tube device, the second switching tube device, ..., the nth switching tube device Circuit board; determine the optimized target parasitic inductance value; set the required error; combine the target parasitic inductance value to calculate and initialize the width of the trace between the driving module and the switching device, and optimize the connection between the driving module and the switching device through multiple iterations of finite element simulation The width of the traces between. The simulated parasitic parameters obtained by the invention have high accuracy, and effectively reduce the parasitic parameters; effectively reduce parallel uneven currents and improve system stability.

Description

technical field [0001] The invention relates to the field of multi-switch device parallel current sharing design, in particular to a multi-parallel switch device current sharing optimization design method based on finite element simulation. Background technique [0002] In recent years, with the rapid development of power electronics technology, the requirements for power devices have become higher and higher. Compared with traditional Si MOSFETs, SiC MOSFETs have higher switching speeds, lower on-state losses and higher blocking voltages. And many other advantages, it can improve the system efficiency, reduce the volume of the equipment and improve the power density of the equipment. However, due to the current technology level and the limitation of cost under specific requirements, the flow capacity of a single SiC MOSFET is limited and cannot meet the requirements of high-power applications. It is often necessary to use multiple SiC MOSFETs in parallel. This parallel appl...

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Problems solved by technology

Among them, the drive circuit plays a vital role in the dynamic current sharing of parallel devices. The gate drive resistance and parasitic inductance in the drive circuit will affect the inconsistency of the drive signals between the branches, which will cause the switch tube that is turned on first to withstand overcurrent. possible damage to the switch tube

The conventional design scheme requires that the driving circuit and the main circuit of each switching tube be arranged in strict symmetry / equal length. The structure of each parallel switch tube is symmetrical. On the basis of the symmetry of the main power circuit of the switch tube, it is difficult to achieve a symmetrical structure for the drive circuit of each parallel switch tube, which brings design difficulties to the parallel connection of multiple tubes.

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