IGBT module detection methods and techniques

Date：2024-03-13 16:21:21Views：10

According to the equivalent circuit diagram of IGBT, it can be seen that if a driving positive voltage is applied between the gate G and the emitter E of IGBT, the MOSFET will conduct. This results in a low resistance state between the collector C and the base of the PNP transistor, causing the transistor to conduct; If the voltage between the gate and emitter of IGBT is 0V, the MOS is cut off, cutting off the supply of base current to the PNP transistor, causing the transistor to cut off. IGBT, like MOSFET, is also a voltage controlled device. A DC voltage of more than ten volts is applied between its gate G and emitter E, and only a leakage current at the uA level flows through, basically not consuming power.

Method for detecting IGBT modules:

Taking two units as an example, measure with an analog multimeter, as follows.

1. Static measurement

Place the multimeter in the multiply by 100 position, connect the black probe to terminal 1 and the red probe to terminal 2, and the displayed resistance should be infinite; Switch the probes and the displayed resistance should be around 400 ohms. Using the same method, connect the black probe to terminal 3 and the red probe to terminal 1, and the displayed resistance should be infinite; The pen should be switched and the displayed resistance should be around 400 ohms. If the above situation is met, it indicates that there is no obvious fault in the two units of this IGBT.

2. Dynamic testing

Place the multimeter in the 10K range, connect the black probe to terminal 4 and the red probe to terminal 5. At this time, connect the black probe to terminal 3 and the red probe to terminal 1. The resistance should be 300-400 ohms. Swapping the probes also indicates that the IGBT unit is intact.

Test the IGBT between terminals 1 and 2 using the same method, and if the above conditions are met, it indicates that the IGBT is also intact. Set the multimeter to the R × 10K Ω position, connect the black probe to the drain terminal D of the IGBT, and the red probe to the source terminal S of the IGBT. At this point, the pointer of the multimeter points to infinity. Touch the gate G and drain D simultaneously with your finger, and the IGBT is triggered to conduct. The pointer of the multimeter swings towards the direction with lower resistance and can stand to indicate a certain position. Then touch both the source electrode S and the gate electrode G with your fingers, and the IGBT will be blocked. The pointer of the multimeter will return to infinity, indicating that the IGBT is good.

However, it should be noted that during the second measurement, the source electrode S and gate electrode G should be short circuited. Any pointer type multimeter can be used to detect IGBT. When judging the quality of an IGBT, be sure to set the multimeter to the R × 10K Ω gear, as the internal battery voltage of the multimeter below the R × 1K Ω gear is too low. When detecting the quality of an IGBT, it is not possible to conduct it and determine its quality.