Power module thermal impedance modeling method based on Fourier analysis spread angle

Abstract

The invention discloses a power module thermal impedance modeling method based on a Fourier analysis spread angle. The method specifically comprises the following steps: S1, listing a Fourier series expression containing an undetermined coefficient of vertical axis heat flux density of each layer in a power module; s2, solving an undetermined coefficient; s3, determining a thermal diffusion angle of each chip on each layer of the power module; s4, determining the self-heating resistance and self-heating capacity of each chip in each layer of the power module; s5, solving the coupling thermal resistance and the coupling thermal capacity between the chips in each layer of the power module; s6, forming a seven-order Cauer thermal network, and calculating a frequency domain expression of self-heating impedance and coupling thermal impedance of each chip; and S7, performing matrix summation and pull-type inverse transformation to obtain a time domain expression of the junction temperature of each chip along with time change under different working conditions. The Fourier series is introduced to accurately describe the transverse thermal diffusion effect, the thermal coupling model of the multiple chips is established based on the diffusion angle, the accuracy and universality of the thermal model at the present stage are improved, and the method is particularly suitable for on-line prediction of the temperature of the power semiconductor chip.

Description

technical field [0001] The invention belongs to the field of power electronic devices, and in particular relates to a power module thermal impedance modeling method based on Fourier analytical diffusion angle. Background technique [0002] As the core component of the new energy vehicle powertrain system, the power module undertakes the functions of motor drive and battery charging and discharging. The trend of high power density and high current density increases the heat flux of the chip, and the multi-chip thermal coupling caused by the lateral thermal diffusion effect causes the power module to withstand greater temperature fluctuations. Due to the frequent switching of chip working conditions under non-stable driving conditions such as vehicle acceleration, variable speed and dynamic load, deceleration and braking, the thermal coupling between chips is more serious, which aggravates local overheating and thermal stress of the power module, threatening the safe operation...

AI Technical Summary

Problems solved by technology

However, at this stage, the calculation of thermal diffusion angle is mainly based on the characteristics of single-layer or double-layer structures, and it is not yet oriented to the complete and complex structure of power modules; There are limitations

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