Overcurrent protection apparatus and protection method for t-type three-level inverter

Abstract

Provided are an overcurrent protection apparatus and protection method for a T-type three-level inverter, the overcurrent protection apparatus comprising a T-type three-level inverter circuit, an overcurrent protection circuit and a switch transistor driving unit, the output end of the T-type three-level inverter circuit being connected to the overcurrent protection circuit, the overcurrent protection circuit being connected to the switch transistor driving unit, and the switch transistor driving unit being connected to transverse transistors and vertical transistors of the T-type three-level inverter circuit. The overcurrent protection apparatus is characterized in that the overcurrent protection unit comprises a delay unit; the delay unit is used for carrying out delay processing on an overcurrent signal and then outputting a delayed overcurrent signal; the overcurrent protection circuit respectively controls on and off of the transverse transistors and of the vertical transistors by means of the overcurrent signal and the delayed overcurrent signal. When the T-type three-level inverter is subjected to overcurrent protection, current is firstly diverted from a vertical transistor to the transverse transistors, and after a certain delay, the current is diverted from the transverse transistors to a switch transistor of another vertical transistor, thereby effectively reducing VDS voltage stress of switch transistors of the inverter, and avoiding a failure and damage of devices.