5SHX1445H0001 3BHL000391P0101 3BHB003230R0101 5SXE05-0152 ABB

Agilent 11730A 8120-8319 Power Sensor Cable 1.5 meter

As we all know,IGBT is a new type of power electronic device that uses MOS to control transistors.It has the characteristics of high voltage,high current,high frequency,and low conduction resistance,and is widely used in inverter circuits of frequency converters.However,due to the poor overcurrent and overvoltage resistance of IGBT,it can be damaged in the event of an accident.Therefore,it is necessary to protect the IGBT.Generally,we design IGBT protection circuits from three aspects:overcurrent,overvoltage,and overheating.

The IGBT can withstand overcurrent for only a few microseconds and has a low resistance to overcurrent.Therefore,the first thing to pay attention to when using IGBT is overcurrent protection.So how to design overcurrent protection according to the driving requirements of IGBT?

he overcurrent protection of IGBT can be divided into two situations:(1)there is no protection function in the drive circuit;(2)The drive circuit has a protection function.For the first case,we can install overcurrent detection devices in the main circuit;For the second case,due to the different types of hybrid drive modules,their output capacity,switching speed,and du/dt bearing capacity are different,so when using them,it is necessary to appropriately select them based on the actual situation.The novel combined IGBT overcurrent protection for high-power voltage source inverters can be protected by blocking the drive signal or reducing the gate voltage.

Overvoltage protection can be carried out from the following aspects:

●Minimize stray inductance in the circuit.

●Adopt absorption circuit.The function of the absorption circuit is:;When the IGBT is turned off,it absorbs the energy released in the inductor to reduce the switching overvoltage.

●Increase the gate resistance Rg appropriately.

The overheat protection of IGBTs generally uses radiators(including ordinary radiators and heat pipe radiators),and can be subjected to forced air cooling.

Comparison between new and old models

Edit Broadcast

In the traditional process of using and designing IGBT,the extensive design mode is basically adopted,which requires a large margin and a large system.However,it is still unable to resist various failures caused by external interference and its own system.So how to break through the traditional circuit protection design of IGBT systems to solve the above problems?

Traditional protected mode

The protection scheme prevents the accumulation of gate charges and the occurrence of spikes in the gate source voltage from damaging the IGBT.Some protective elements can be installed between the G electrode and the E electrode,such as the resistor RGE in Figure 1,to discharge the accumulated charge at the gate electrode(its resistance value can be taken as 5kΩ);Two voltage stabilizing diodes V1 and V2 in reverse series are used to prevent gate source voltage spikes from damaging the IGBT.In addition,there are also designs to achieve isolation between the control circuit part and the driven IGBT,as well as design of a drive pulse circuit suitable for the gate electrode.However,even so,in actual industrial environments,the above solutions still have relatively high product failure rates-sometimes exceeding 5%.Relevant experimental data and research indicate that this is closely related to transient surges,static electricity,and high-frequency electronic interference.However,the response time and current withstand ability of the regulator tube here are far from sufficient,leading to overheating and damage of the IGBT