电气工程及其自动化专业英语》课程论文

重庆邮电大学移通学院《电气工程及其自动化专业英语》课程论文

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Insulated-gate Bipolar Transistor Basics 【Abstract】Modern Power Electronics makes generous use of MOSFETs and IGBTs in most applications, and, if the present trend is any indication, the future will see more and more applications making use of MOSFETs and IGBTs. For high-voltage or high-power applications, it may be necessary to realize a logical switch by connecting smaller units in parallel and series to achieve high availability, high-frequency operation, and low cost due to build-in redundancy, reduced dynamic losses, and modular use of standardized units, respectively. IGBTs are very convenient to realize such units, because of quasi-linear controllability via a gate terminal. This thesis investigates control methodologies for power MOS semiconductor switches with focus on combined parallel and series connection of IGBT/diode modules. It is proposed to provide each IGBT with primary local control to monitor and adjust the IGBT's static and dynamic behavior. Secondary (global) control synchronizes the operation of multiple IGBTs. A globally synchronous clock can also be derived locally. This makes it possible to use low-cost low-bandwidth data links between series-connected units. Thereby, a flexible master- slave approach can avoid the need of dedicated global control. That is, the entire system is manageable by the local gate drive circuitry.

Keywords:IGBT applications MOSFET characteristic

Introduction:The IGBT is a semiconductor device with four alternating layers (P-N-P-N) that are controlled by a metal-oxide-semiconductor (MOS) gate structure without regenerative action. This mode of operation was first proposed by Yamagami in his Japanese patent S47-21739, which was filed in 1968. This mode of operation was first experimentally reported in the lateral four layer device (SCR) by B.W. Scharf and J.D. Plummer in 1978.[1] This mode of operation was also experimentally discovered in vertical device in 1979 by B. J. Baliga.[2]The device structure was referred to as a ‘V-groove MOSFET device with the drain region replaced by a p-type Anode Region’ in this paper and subsequently as 'the insulated-gate rectifier' (IGR), the insulated-gate transistor (IGT), the conductivity-modulated field-effect transistor (COMFET) and "bipolar-mode MOSFET".[3]

IGBT Fundamentals:The Insulated Gate Bipolar Transistor (IGBT) is a minority-carrier device with high input impedance and large bipolar current-carrying capability. Many designers view IGBT as a device with MOS input characteristics and bipolar output characteristic that is a voltage-controlled bipolar device. To make use of the advantages of both Power MOSFET and BJT, the IGBT has been introduced. It’s a fun ctional integration of Power MOSFET and BJT devices in monolithic form. It combines the best attributes of both to achieve optimal device characteristics.

1.The main advantages of IGBT over a Power MOSFET and a BJT are:

1. It has a very low on-state voltage drop due to conductivity modulation and has superior on-state current density. So smaller chip size is possible and the cost can be reduced.