System for protecting overcurrent and short-circuited circuit

Abstract

The invention belongs to the circuit field, in particular to a system for protecting an overcurrent and short-circuited circuit. The system comprises an I_SHUNT+, an I_SHUNT-, a diverter, a transistor, capacitors, resistors, a high level device, a driving circuit and a protection signal, wherein the I_SHUNT+ and the I_SHUNT- are arranged at two ends of the diverter to be in parallel connection with a base electrode circuit of the transistor and the diverter, the resistors are arranged on the I_SHUNT, the capacitors are arranged at the front ends of the resistors, the transistor is connected with the resistors, the resistors are connected with the high level device, the resistors are connected with the protection signal, the resistors and the capacitors form a small inertia filter, and a signal ground of the driving circuit is connected with an emission electrode of a lower bridge arm of a power converter. The system is a few in elements, low in cost, small in printed circuit board (PCB) occupancy, reliable and stable in power conversion, strong in interference resistance, quick in protection speed and capable of achieving most effective power tube protection and overcoming existing shortcomings.

Description

Technical field: [0001] The invention belongs to the field of circuits, and in particular relates to a system for protecting overcurrent and short circuit circuits. Background technique: [0002] At present, there are several ways to protect IGBT: [0003] 1): Use a Hall current sensor to detect the output current of the power conversion device, set up a current limiting threshold, compare with a comparator, and output an overcurrent protection signal. [0004] Disadvantages: The Hall sensor works in a high-radiation environment, and the output current signal is noisy, which may easily cause system malfunction. At the same time, the Hall device is very expensive, and the system cost is relatively high. Also need to provide power, some devices also need to provide dual power. [0005] 2): Use the transformer to detect the current, set up the current-limiting threshold, compare with the comparator, and output the over-current protection signal. Disadvantage: This method ca...

AI Technical Summary

Problems solved by technology

[0004] Disadvantages: The Hall sensor works in a high-radiation environment, and the output current signal is noisy, which may easily cause system malfunction

Disadvantage: This method cannot detect DC current

[0007] Disadvantages: Occupies a lot of circuit board area, requires an op amp and a comparator, and the cost is high

[0009] Disadvantages: Different types of power tubes have different tube pressure drop characteristics, and are also affected by operating temperature

[0013] 2: The trigger voltage of pin 8 is very low, and it will malfunction under severe interference;

[0014] 3: This kind of protection circuit can only cooperate with specific modules, and the versatility is poor

[0015] The above-mentioned common IGBT protection often brings many changes in the work, and users also very much hope that the ideal IGBT protection will come out

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