Short-circuit protection circuit for APF high-power IGBT

Abstract

The invention discloses a short-circuit protection circuit for an APF high-power IGBT. The short-circuit protection circuit comprises the working control circuit of the IGBT and the short-circuit protection circuit of the IGBT, the working control circuit of the IGBT is used for controlling the IGBT to work or not, and the short-circuit protection circuit of the IGBT is used for monitoring the short circuit currents of the IGBT and preventing the short circuit of the IGBT from causing overvoltages to damage the IGBT through a slowly lowered grid voltage circuit. The short-circuit protection circuit of the IGBT comprises the working control circuit of the short-circuit control circuit, the detecting circuit of the short-circuit protection circuit, the slowly lowered grid voltage circuit and a latch protecting resetting circuit, wherein the working control circuit is used for controlling the short-circuit protection circuit to work or not, the detecting circuit is used for detecting the voltage of the IGBT, the slowly lowered grid voltage circuit is used for slowly lowering grid voltages, and the latch protecting resetting circuit is used for protecting and locking a PWM, and completely turning off the IGBT. The short-circuit protection circuit for the APF high-power IGBT has the advantages of improving the reliability of the working circuit, and reducing the overvoltages in a turning off process by adopting the soft turn-off mode of slowly lowering IGBT grid voltages when a short circuit occurs.

Description

technical field [0001] The invention belongs to the field of power electronic control and protection, in particular to a short-circuit protection circuit for APF high-power IGBT. Background technique [0002] Since the world's first MOSFET and IGBT came out, voltage-controlled power electronic devices, especially IGBT, are undergoing a rapid development process. The voltage of the IGBT single-module device is getting higher and higher, and the current is getting bigger and bigger. At the same time, the supporting drive devices have also been vigorously developed. As the device application field becomes wider and wider, the conversion power of the power supply equipment is getting larger and larger, especially in the aspect of harmonic control, the active power filter uses the IGBT switching action to compensate the harmonic, and when the IGBT is short-circuited, it adopts the general speed blocking Gate voltage, too high current change rate di / dt will cause overvoltage, an...

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Problems solved by technology

As the device application field becomes wider and wider, the conversion power of the power supply equipment is getting larger and larger, especially in the aspect of harmonic control, the active power filter uses the IGBT switching action to compensate the harmonic, and when the IGBT is short-circuited, it adopts the general speed blocking Gate voltage, too high current change rate di / dt will cause overvoltage, and high voltage may cause IGBT to lock and cause damage. Usually, in order to avoid short-circuit protection causing overvoltage and damage to IGBT, generally increase the drive resistance. Prolong the off time and add a surge absorbing circuit to the bus, but increasing the driving resistance will also increase the switching loss, affect the waveform quality, and reduce the working reliability. In order to improve the working circuit reliability, slowly lower the IGBT grid Soft turn-off mode of extreme voltage to reduce overvoltage during turn-off

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