绝缘栅双极型晶体管(igbt)的保护（Protection of insulated gate bipolar transistor (IGBT)）.doc

绝缘栅双极型晶体管(igbt)的保护（Protection of insulated gate bipolar transistor (IGBT)） IGBT insulated gate bipolar transistor is a device by MOSFET and bipolar transistors compounded, the input is very MOSFET, very PNP output transistor, therefore, can be regarded as the input of MOS darlington. It blends the advantages of these two kinds of devices, not only has the advantages of simple and fast MOSFET device driver, and has the advantages of large capacity, bipolar devices and is widely used in modern power electronic technology. Switching power supply device in high power, IGBT control because of its simple driving circuit, high frequency and large capacity characteristics, has gradually replaced thethyristor or GTO. But in switching power supply device, it works in high frequency and high voltage, large current conditions, making it easy to damage, in addition, as first level the power system, due to the power fluctuations, lightning and other reasons make it bear greater stress, so the IGBT is directly related to the reliability of power supply the reliability of the. Therefore, in the selection of IGBT in addition to make derating considerations, the protection of IGBT design is the power supply needs a link priority. 1 the working principle of IGBT If the IGBT between gate and emitter coupled with the driving voltage is MOSFET, conduction between the collector and the base of the PNP transistor into a low resistance state and the transistor conduction; if the voltage between the gate and emitter of IGBT 0V, MOSFET PNP, cut off the current supply transistor base, making transistor cut-off. Therefore, IGBT is safe and reliable and it is decided by the following factors: IGBT - voltage between gate and emitter; IGBT - the voltage between the collector and emitter; Through IGBT - Collector Emitter current; - IGBT junction temperature. If the voltage between the gate and the IGBT emitter, driving voltage is too low, then IGBT cannot work normally and steady, if higher than gr