Circuit and method for detecting overvoltage breakdown characteristics of IGBT

Abstract

The invention provides a circuit and method for detecting overvoltage breakdown characteristics of an IGBT. The circuit comprises a bus DC power supply, a solid-state circuit breaker, an energy storage capacitor, a boost power electronic switch and a double-pulse test circuit. According to the invention, a double-pulse test method is adopted, so avalanche breakdown caused by over-high withstand voltage when the IGBT turns off a transient over-high voltage peak and turns off a steady state can be realized; the withstand voltage of the IGBT can be rapidly switched by arranging the boost power electronic switch, and the time for the IGBT to tolerate the over-high voltage in the turn-off steady state is accurately controlled; in addition, due to the fact that over-long avalanche breakdown is prone to causing an over-current fault, the solid-state circuit breaker is arranged, and the serious tube explosion phenomenon caused by energy accumulation when permanent breakdown happens to the IGBTis prevented.

Description

technical field [0001] The invention relates to an IGBT overvoltage breakdown detection circuit and method, in particular to a circuit and method for detecting IGBT turn-off steady-state overvoltage breakdown characteristics, belonging to the field of power electronics. Background technique [0002] The overvoltage breakdown phenomenon of power devices such as high-power IGBTs is one of the common faults in multi-level power electronic devices. Affected by improper circuit design of power electronic devices, sudden load changes, power grid fluctuations, misoperation of power devices and electromagnetic interference, it is easy to cause overvoltage breakdown faults of power devices. After long-term and high-frequency short-term overvoltage, the aging of power devices will be accelerated, and even irreversible permanent breakdown failure will occur. [0003] Usually, there are two working states of IGBT that will cause overvoltage breakdown. The first is the IGBT turn-off tra...

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Problems solved by technology

[0003] Usually, there are two working states of IGBT that will cause overvoltage breakdown. The first is the IGBT turn-off transient. When the stray inductance of the current loop is too high, the load current is large or overcurrent occurs, the IGBT in the turn-off transient When the collector current drops, a huge voltage spike is superimposed, exceeding the rated voltage, resulting in an overvoltage breakdown fault; studies have shown that short-term overvoltage breakdown will not cause IGBT device failure, but after multiple pulse cycles After that, the device will permanently fail and cause secondary failures such as short circuit and overheating with a high probability

The other state is in the steady state of IGBT off. When the bus voltage fluctuates or other power devices are accidentally turned on or not completely turned off, the IGBT is subjected to an excessively high voltage and exceeds the rated voltage. The duration of the overvoltage state usually lasts Longer than the IGBT turn-off transient, resulting in rapid breakdown of the device, resulting in secondary failure

[0004] However, most of the current overvoltage detection methods only detect the overvoltage breakdown characteristics of the IGBT in the turn-off transient state, and do not detect the overvoltage breakdown characteristics of the IGBT in the turn-off steady state.

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