IGBT Test Methods

The word IGBT is short for for Insulated Gate Bipolar Transistor. It may be regarded as a Transistor having a MOSFET front-end. It's three devices (or leads) labeled Gate, Collector and Emitter. Some IGBT's possess a built-in protection diode. This diode is connected over the Collector and Emitter devices. It's added for transient current protection once the IGBT is switching Inductive loads.

When these products are thought 'suspect' it's important to validate their operation via a functional test procedure. 1 of 2 techniques may be used:

The very first test method will validate the health of the security diode, and also the resistance from the Collector and Emitter devices. It's not a definitive test, and can find 80% of faulty products. This really is because of the truth that most faulty IGBT's show a minimal resistance or short over the Collector and Emitter devices once the system is stressed.

To do this test will need a DVM (Digital-Volt-Meter). Set the DVM towards the Diode Test position, and ensure the device tests the following:

Attach the Red-colored Lead from the DVM towards the Collector Terminal and Black Result in the Emitter Terminal. Confirm a wide open circuit condition.

Attach the Red-colored Lead from the DVM towards the Emitter Terminal and Black Result in the Collector Terminal. Confirm a wide open circuit condition (IGBT with no protection diode). When the DVM shows a forward current drop of .2 to .8 VDC this means the IGBT includes a built-in protection diode. These two answers are normal test conditions and are utilized to confirm if the IGBT includes a protection diode, and when it will, whether it's functional or otherwise.

The 2nd test method will look into the IGBT's functionality, by gating the unit. To do this test will need an IGBT Tester. Make sure the unit tests the following:

Attach the IGBT Tester results in the Gate, Collector and Emitter Devices. Make sure the unit Passing Brought isn't lit.

Press the exam Button, and ensure the Passing Brought lights.

Turn back Collector and Emitter leads. Don't press the exam Button. When the Passing Brought lights the IGBT includes a built-in protection diode. This can be a normal test condition for this kind of device. When the Passing Brought doesn't light then your IGBT doesn't have a built-in protection diode. This is an ordinary test condition for this kind of device.

You should observe that Functional test from the IGBT ought to always be carried out once the system is out-of-circuit. Quite simply, it ought to be taken off the merchandise and also have not one other electrical connections in position, apart from individuals layed out within the Test procedure.