Three methods for quickly determining whether IGBT has been damaged

Date：2024-03-06 16:26:12Views：21

With the increasing popularity of high-power power supply equipment, the role of IGBT in high-power power supply equipment is also becoming increasingly important. Therefore, it is necessary to have a comprehensive understanding of IGBT knowledge. As the frequency of use increases, it is inevitable that IGBTs will be damaged during use. At this time, developers need to quickly and accurately identify. This article will tell you the methods to quickly determine whether IGBTs are damaged from several aspects.

Judging polarity

Firstly, set the multimeter to the R × 1K Ω gear. When measuring with a multimeter, if the resistance value between one pole and the other two poles is infinite, and after switching the probes, the resistance value between that pole and the other two poles is still infinite, then it is judged that this pole is a gate (G). Measure the remaining two poles with a multimeter. If the measured resistance value is infinite, replace the probe and measure the resistance value to be smaller. In a measurement with a smaller resistance value, it is judged that the red probe is connected to the collector (C); The black probe is connected to the emitter (E).

Judging good or bad

Set the multimeter to the R × 10K Ω position, connect the black probe to the collector (C) of the IGBT, and the red probe to the emitter (E) of the IGBT. At this time, the pointer of the multimeter is at zero. Touch the gate (G) and collector (C) 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 the gate (G) and emitter (E) simultaneously with your fingers, and the IGBT will be blocked, causing the pointer of the multimeter to return to zero. At this point, it can be determined that IGBT is good.

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. This method can also be used to detect the quality of power field-effect transistors (P-MOSFETs).

Inverter IGBT module detection

Set the digital multimeter to the diode test mode and test the forward and reverse diode characteristics between the IGBT modules c1e1 and c2e2, as well as between the gate G and e1 and e2, to determine if the IGBT module is intact.

Taking the six phase module as an example. Remove the wires of the U, V, and W phases on the load side, use a diode test gear, connect the red probe to P (collector c1), and measure U, V, and W in sequence with the black probe. The multimeter displays the maximum value; Turn the probe upside down, connect the black probe to P, and measure U, V, and W with the red probe. The multimeter displays a value of around 400. Connect the red probe to N (emitter e2), measure U, V, and W with the black probe, and the multimeter will display a value of around 400; The black probe is connected to P, while the red probe measures U, V, and W. The multimeter displays the maximum value. The forward and reverse characteristics between each phase should be the same. If there is a difference, it indicates that the performance of the IGBT module has deteriorated and should be replaced. When the IGBT module is damaged, only a breakdown short circuit occurs.

The red and black probes measure the forward and reverse characteristics between gate G and emitter E respectively. The values measured by the multimeter twice are both the maximum, indicating that the IGBT module gate is normal. If there is a numerical display, the gate performance will deteriorate and this module should be replaced. When the forward and reverse test results are zero, it indicates that the detected phase gate has been broken and short circuited. When the gate is damaged, the voltage regulator protecting the gate on the circuit board will also break down and be damaged.

When there is a problem with IGBT, everyone can make their own judgment according to the situation provided in the article, which can help everyone save a lot of time and cost. Friends who have not yet encountered IGBT issues can also save this article for easy reference when encountering problems.