Overcurrent protection device and protection method for T-type three-level inverter

Abstract

The invention belongs to the technical field of electronic circuits, and discloses an overcurrent protection circuit and protection method of a T-type three-level inverter, and the overcurrent protection circuit comprises a T-type three-level inverter circuit, an overcurrent protection circuit and a switching tube driving unit. The output end of the T-type three-level inverter circuit is connected with the over-current protection circuit, the over-current protection circuit is connected with the switching tube driving unit, and the switching tube driving unit is connected with a transverse tube and a vertical tube of the T-type three-level inverter circuit; the over-current protection circuit is characterized in that the over-current protection unit comprises a delay unit, the delay unit is used for delaying over-current signals and then outputting over-current delay signals, and the over-current protection circuit controls turn-off of the transverse tube and turn-off of the vertical tube through the over-current signals and the over-current delay signals respectively. When the T-type three-level inverter is subjected to overcurrent protection, the current is converted from the vertical tube to the transverse tube, and is converted from the transverse tube to the switching tube of the other vertical tube after a certain delay, so that the VDS voltage stress of the inversion switching tube is effectively reduced, and the failure and damage of a device are avoided.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and in particular relates to an overcurrent protection device and a protection method of a T-type three-level inverter. Background technique [0002] The T-type three-level circuit has the advantages of simple control, high reliability, and easy device selection. It is a commonly used circuit for three-phase photovoltaic inverters. [0003] At present, most of the T-type three-level inverter products on the market use the overcurrent protection method of turning off all the switches at the same time when the AC side overcurrent protection occurs. If all the switches of the inverter are turned off at the same time in the T-type three-level circuit, the large current on the AC side is commutated from the switch tube of the standpipe to the anti-parallel diode of the switch tube of the other standpipe, and the current is drawn from the bus bar, which is easy to cause the switch tube to f...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide an overcurrent protection device and protection method for a T-type three-level inverter, so as to solve the problem that if the T-type three-level circuit turns off all the switch tubes of the inverter at the same time, it is easy to cause the VDS voltage peak of the switch tubes And exceed its VDS maximum withstand voltage stress, which leads to technical problems of its failure

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