Temperature detecting circuit for IGBT module

Abstract

The invention relates to a temperature detecting circuit for an IGBT module. The temperature detecting circuit for the IGBT module comprise a thermistor Rt, a chip U1 for converting an analog quantityinto an pulse quantity, and an FPGA, wherein the thermistor Rt is installed inside the IGBT module; the chip U1 for converting the analog quantity into the pulse quantity is connected with the thermistor Rt and used for converting an analog quantity of resistance change of the thermistor Rt into a digital quantity of a pulse width change; and the FPGA is connected with the chip U1 for convertingthe analog quantity into the pulse quantity, and the FPGA is used for detecting a pulse width or a duty ratio, calculating an NTC resistance value, and reading an corresponding IGBT module junction temperature through a look-up table method. Compared with the prior art, the temperature detecting circuit for the IGBT module has the advantages of having good linearity, high precision, and safety isolation.

Description

technical field [0001] The invention relates to a temperature detection circuit, in particular to a temperature detection circuit for an IGBT module. Background technique [0002] With the rapid development of modern industry, power electronics technology has also been advancing by leaps and bounds. Power semiconductors are the most important devices, and power modules are widely used in the field of power electronics conversion, especially in new energy vehicles, energy storage, and frequency conversion. Power modules play an extremely important role in popular industries such as power converters, active filters, and SVG. In the actual application process, the high IGBT junction temperature caused by uneven heat dissipation of the substrate and internal overcurrent is one of the main reasons for module failure. An important factor restricting the application of semiconductors is also their maximum junction temperature Tvj, so whether it is Whether the application developer...

AI Technical Summary

Problems solved by technology

However, due to the characteristics of NTC sensors, the resistance value will change with different temperatures, and the range of change can reach more than a thousand times. The AD sampling digits of common single-chip microcomputers are usually ten digits, plus the system noise during the acquisition process, the measurement error It is difficult to meet the requirements of high-precision temperature measurement in the whole temperature range

[0005] 2. The comparator comparison method, the circuit is simple, it can only be used as an over-temperature protection judgment for setting the maximum temperature of the IGBT, and the junction temperature of the module cannot be measured linearly

[0006] 3. The indirect measurement method is not to directly measure the actual temperature of the chip, but to measure the temperature of other reference points in the system, usually to detect the temperature of the substrate or radiator of the IGBT module, which cannot accurately and effectively measure the junction temperature of the module

[0007] Moreover, these methods do not have isolation detection, and the linearity and accuracy are not high.

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