Short circuit detection and driving control with no blanking time for high voltage high power insulated gate bipolar transistors

Abstract

Insulated gate bipolar transistors (IGBT) short-circuit (SC) protection is one of the most important protection methods for IGBT converter equipment. The fast detection and protection response time could reduce the permanent damage of devices, and extend their use life cycle. At present, the collector emitter voltage vce desaturation method is widely used in the commercial IGBT drive circuit, which has blanking time of fault detection and protection. In this paper, an improved adaptive vce SC detection and protection is proposed to realize the blanking time adjustment under different SC conditions. By the determination of the di/dt characteristics of the current variation on the parasitic inductance between the power emitter and the Kelvin emitter of IGBT modules, the execution time of the two detection methods can be set. According to the switch process and the SC type, the corresponding logic processing will be carried out to realize the fast detection of different SC conditions. The circuit scheme without blanking time detection and protection is designed, and the circuit is modelled and simulated by Pspice. The IGBT driving circuit SC test without blanking time detection and soft turn-off protection has been carried out. Simulation and test results can verify the feasibility of the proposed circuit.