How much capacitance is measured by LCR in IGBT module?

振动试验仪器

How much capacitance is measured by LCR in IGBT module? [Copy link]

 

Use an LCR meter to measure the capacitance between GE and CE of DM2G100SH6N. The LCR meter is model XJW01.

GE 8.94nF Q 999 ESR>20M CE: 8.39nF Q63 ESR 1.21M

Measure 2.2uF feedthrough capacitor 2.15uF 999 ESR -0.001 Om

The general experience is to use the resistance range of the multimeter to measure the resistance between GE and CE. Even the 220M resistance range cannot fully measure the resistance between the electrodes. At this time, measuring capacitance is another option.

You cannot measure the difference between different modules of the same model using the resistance range, but there will be differences when measuring with an LCR meter. The results measured by different LCR meters will have deviations, and there should be a range of measurement values.

If any measurement is required, upload the measurement results.

振动试验仪器

People usually use a multimeter to test power MOSFET or IGBT. When measuring the inter-electrode resistance of DS, it is infinite. The range of the multimeter is 20M, 40M or 220M. When the upper limit is exceeded, the multimeter will display infinity. The inter-electrode resistance of DS should have a certain value, such as a resistance of several hundred M or several G, but the multimeter is over-range and cannot display it. It is easy to convert a large resistance into a capacitance for measurement. The multimeter can display it normally. How big is this capacitance? It is necessary to accumulate data.

振动试验仪器

When the resistance range of the multimeter is infinite, the test leads are open and the corresponding capacitance is 0; when the resistance leads are short-circuited and the resistance is 0, the corresponding capacitance is infinite.

The inter-electrode resistance of DS should have a corresponding value. It is not truly infinite, but it is also not acceptable if it is too small. When converted into measuring the capacitance value between DS, there should be a corresponding value.

It is also very difficult to measure a resistor of several G.

振动试验仪器

Measurement

Static measurement: put the multimeter in the multiplier 100K position, measure the black probe connected to terminal 1 and the red probe connected to terminal 2, the displayed resistance should be infinite; swap the probes, the displayed resistance should be around 400 ohms. Use the same method to measure the black probe connected to terminal 3 and the red probe connected to terminal 1, the displayed resistance should be infinite; swap the probes, the displayed resistance should be around 400 ohms. If the above situation is met, it means that there is no obvious fault in the two units of this IGBT. Dynamic test: put the multimeter in the multiplier 10K position, connect the black probe to terminal 4 and the red probe to terminal 5, now the black probe is connected to terminal 3 and the red probe is connected to terminal 1, the resistance should be 300-400 ohms, swap the probes and there is also a resistance of about 300-400 ohms, indicating that this IGBT unit is intact. Use the same method to test the IGBT between terminals 1 and 2. If the above situation is met, it means that the IGBT is also intact.　

Set the multimeter to the R×10KΩ position, connect the black test lead to the drain (D) of the IGBT, and the red test lead to the source (S) of the IGBT. At this time, the pointer of the multimeter points to infinity. Touch the gate (G) and drain (D) with your fingers at the same time. At this time, the IGBT is triggered to conduct, and the pointer of the multimeter swings to the direction of smaller resistance and can stop and indicate a certain position. Then touch the source (S) and gate (G) with your fingers at the same time. At this time, the IGBT is blocked, and the pointer of the multimeter returns to infinity. At this time, it can be judged that the IGBT is good.

Note: If you are measuring for the second time, you should short-circuit the source (S) and gate (G). Any pointer multimeter can be used to test IGBT. When judging the quality of IGBT, you must set the multimeter to the R×10KΩ range, because the internal battery voltage of the multimeter below the R×1KΩ range is too low, and the IGBT cannot be turned on during the test, and it is impossible to judge the quality of the IGBT.