Multiple igbt short circuit detection and protection method and device

Abstract

The invention discloses a method and device for short-circuit detection and protection of multiple IGBTs. The method steps are: 1) sending a driving pulse to each IGBT, the IGBT receives the driving pulse and drives the IGBT to turn on; 2) real-time detection of the voltage at both ends of each IGBT Value, judge whether it is greater than the preset short-circuit voltage threshold value, if yes, judge it as the IGBT internal open-circuit fault state and send the judgment result; 3) Convert the detected short-circuit voltage into a short-circuit current value and calculate the short-circuit voltage and short-circuit current The target multiple, judge whether the target multiple is greater than the preset multiple threshold value, if yes, reduce the driving pulse to negative level, and drive the IGBT to turn off; the device includes multiple short-circuit detection for real-time detection of IGBT faults and shutdown protection protection module. The invention has the advantages of simple implementation method, consistent protection parameters and the ability to perform unified and coordinated detection and protection for multiple IGBTs.

Description

technical field [0001] The invention relates to the field of IGBTs, in particular to a multiple IGBT short-circuit detection and protection method and device. Background technique [0002] For the detection and protection of IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor), it mainly includes the following three methods: [0003] (1) Realized by using analog discrete components, however, the number of components required by this type of method is large and complex. Especially for systems with multiple IGBTs, due to the discrete nature of analog devices, there will be inconsistencies in the protection parameters, and the protection parameters will shift with time and temperature changes. [0004] (2) It is implemented by an integrated module. The integrated module is actually composed of analog discrete components. Because it is packaged into a module, it can be used conveniently. However, this solution also has the above-mentioned defects, that is...

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Problems solved by technology

[0003] (1) Implemented with analog discrete components, however, the number of components required for this type of approach is high and complex

Especially for systems with multiple IGBTs, due to the discreteness of analog devices, there will be inconsistencies in protection parameters, and protection parameters will shift with time and temperature changes

[0004] (2) It is implemented by an integrated module. The integrated module is actually composed of analog discrete components. Because it is packaged into a module, it can be used conveniently. However, this solution also has the above-mentioned defects, that is, for systems with multiple IGBTs, the protection parameters are inconsistent and the protection parameters Shifts over time as temperature changes

[0005] In the above two schemes, when the IGBT protection threshold is used in the field, it cannot be adjusted according to the specific situation; when the IGBT fails, the short-circuit current value cannot be accurately quantified, and it cannot be displayed for real-time observation, which is not convenient for post-analysis

[0006] (3) Hall element is used for IGBT short-circuit detection, but this kind of scheme has the problem of the speed of protection response and cannot realize the miniaturization of the product, so it is rarely used in actual products

The capacitance value is selected according to the voltage range allowed by the chip. If the value is too large, it will affect the signal transmission speed, and if it is too small, there will be no suppression effect;

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