The Tips for Using and Keeping IGBT Modules

Using tips

Because IGBT module is MOSFET structure, IGBT grid can realize electrical isolation through oxide film and emitter. Because the oxidation film is very thin, and the general breakdown voltage is up to 20 ~ 30 V. So static led to the grid breakdown is one of the common causes of the failure of IGBT. Therefore we should pay attention to the following points:

• In the use of modules, try not to touch the driver terminal part, when we must touch the module, we should first use great resistance to discharge static of human body or clothes, then touch it;
• In connecting conductive material with module to drive terminals, don’t plug in module before wiring connected;
• Operating under the condition of the bottom well grounded.

In the application, although the grid driving voltage is no more than grid maximum rated voltage, parasitic inductance connected with the grid and capacitance coupling between grid and collector also can produce the oscillation voltage to make oxidation layer damage. Therefore, we usually adopted twisted pair to transmit signals to reduce parasitic inductance. In the grid connection, small resistance in tandem can also inhibit the oscillation voltage.

In addition, in the grid-emitter open circuit, if add voltage between the collector and the emitter, the collector potential change, as the collector has the leakage current through, grid potential rise, collector has current flow. At this time, if there are high voltage between the collector and the emitter, it has the potential to make IGBT fever even damage.

In the use of IGBT occasions, when a grid loop was not normal or grid loop damaged (grid unconnected), if we ad voltage in the main loop, the IGBT will damage. to prevent such failure, about 10 K Ω resistance should be added in tandem connection between the grid and emitter.

In the installation or replacement of IGBT module, great attention should be pay to the contact state and tighten degree of the IGBT module and heat sink. In order to reduce the thermal contact resistance, the best way is to daub silicon grease between the radiator and IGBT module. As heat sinks are installed the cooling fans at the bottom, when a cooling fan of heat sink has a damage, it will cause IGBT module fever and failure. Therefore cooling fans should be checked regularly, generally temperature sensors should be installed in the heat sink near IGBT module, when the temperature is high, and it will alarm or stop IGBT module working.

Matters need attention

• General place to save IGBT module should maintain normal temperature and normal wet state, and should not deviate from too large. The provisions of the normal temperature is 5 ℃ ~ 35, normal wet provisions is 45 to 75% or so. In the winter, in dry areas, we need wet machine to wet;
• As far as possible from corrosive gas or dust occasions;
• In jumpy temperature changes, IGBT module surface may have the phenomenon of dew, therefore IGBT module should be put in temperature changes smaller place;
• Don’t pile up weight on IGBT module;
• IGBT module container should choose containers without static electricity.