How To Test IGBT?

The INSULATED GATE BIPOLAR TRANSISTOR (IGBT) is a three-terminal power semiconductor device  used as an electronic switch and in newer devices is high efficiency and fast switching
It switches electric power in many modern appliances:electric cars, trains,variable speed refrigerators, air-conditioners and even stereo systems with switching amplifiers. Since it is designed to turn on and off rapidly, amplifiers that use it often synthesize complex wave forms with pulse width modulation and low-pass filters. In switching applications modern devices boast pulse repetition rates well into the ultrasonic range—frequencies which are at least ten times the highest audio frequency handled by the device when used as an analog audio amplifier.
The IGBT combines the simple gate-drive characteristics of the MOSFETs with the high-current and low-saturation-voltage capability of bipolar transistors by combining an isolated gate FET for the control input, and a bipolar power transistor as a switch, in a single device. The IGBT is used in medium- to high-power applications such as switched-mode power supplies, traction motor control and induction heating. Large IGBT modules typically consist of many devices in parallel and can have very high current handling capabilities in the order of hundreds of amperes with blocking voltages of 6000 V, equating to hundreds of kilowatts.
The IGBT combines the advantages of a power MOSFET and a bipolar power transistor. Similarly its structure is a combination of the two devices. As show in below, the input has a MOS gate structure, and the output is a wide base PNP transistor. The base drive current for the PNP transistor is fed through the input channel. Besides the PNP transistor, there is an NPN transistor, which is designed to be inactivated by shorting the base and the emitter to the MOSFET source metal. The 4 layers of PNPN, which comprises the PNP transistor and the NPN transistor form a thyristor structure, which causes the possibility of a latch-up. Unlike the power MOSFET, it does not have an integral reverse diode that exists parasitically, and because of this it needs to be connected with the appropriate fast recovery diode when needed.

Short out G1 to E1 and G2 to E2.
With a multimeter set to check diodes, check across the C1-C2 E1 junction.
With the (+) probe on C1 and the (-) probe on C2 E1, you should see an open circuit.
Change the probes, You should see a diode drop on the meter.
Check across the C2 E1-E2 junction.
With the (+) probe on C2E1 and the (-) probe on E2, you should see an open circuit.
Change the probes, You should see a diode drop on the meter.
Connect  6 volt battery, connect the (+) terminal to G1 and the (-) terminal to E1. Using your meter(set to check diodes), should see a diode drop across the C1-C2E1 junction in both directions now.
Connect the (+) terminal to G2 and the (-) terminal to E2. You should see a diode drop across the C2E1-E2 junction in both directions here as well.
VERIFICATION:- If the IGBT passed all of the above tests, the IGBT is good.
You may be able to use a second multimeter as a voltage source by setting it to check resistance at its lowest available resistance scale. The (+) probe is the positive side. However, not all meters provide enough DC voltage for this, and may even give you false readings. A known DC voltage from 8 to 15 volts is recommended instead. 


Assemble and test your IGBT given circuits:-

  1. Vikas narang August 21, 2014
    • Keerthi August 21, 2014
  2. Sanjeev kumar December 5, 2014
  3. pravin shinde March 5, 2015
  4. Razik April 4, 2015
    • Keerthi April 5, 2015
  5. Dohos Peter May 13, 2015

Leave a Reply

Your email address will not be published. Required fields are marked *