Regarding the insulation spacing of IGBT drive circuits

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Regarding the insulation spacing of IGBT drive circuits [Copy link]

Dear seniors, I would like to ask a question. When I was designing the drive circuit for Infineon's IGBT module, I did not figure out the problem of high voltage insulation. The IGBT is a 1200V/75A sixpack module, and the package is in the form of pins. So what voltage level should be used to calculate the electrical insulation distance between the g-pole and the e-pole of each IGBT. Assuming that the bus voltage is 600V, should the electrical insulation distance between the g-pole and the e-pole of each IGBT be calculated as 600V? What about the electrical insulation distance between the g-pole and the e-pole of the upper and lower tubes of the same bridge arm? What about the tubes between different phase bridge arms? Is the 2mm spacing between the two wires enough for 600V?

qwqwqw2088

It depends on the power supply you design. The electrical insulation distance should be based on the three types of equipment in the safety regulations. Class I equipment is a metal shell + 3-pin plug (that is, with grounding); Class II equipment is a plastic shell + 2-pin plug; Class III equipment is battery-powered or adapter-powered, such as laptops and flashlights;

qwqwqw2088

The electrical clearance should be determined based on the measured working voltage and insulation level. The creepage distance can be determined based on the working voltage and insulation level. The insulation level is divided into 5 levels. These should be based on the standard.

elvike

Then you don't understand the working state of the bridge arm during inversion. The voltage between g and e is the driving voltage, not based on the bus voltage level. The voltage between the upper and lower tubes of the bridge arm is based on the bus voltage level, because when the tube is turned on and off, the potential of the AC output point is changing. If you understand the principle clearly, you can find the answers to these questions yourself.

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elvike posted on 2017-11-15 12:12 Then you don't understand the working state of the bridge arm during inversion. The voltage between g and e is the driving voltage, which is not based on the bus voltage level. The driving voltage of the bridge arm...

Assuming that the upper tube is turned on and the lower tube is turned off, the point e of the upper tube is at the same potential as the positive bus voltage, then at this time, isn't the voltage difference between points g and e the bus voltage?

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qwqwqw2088 posted on 2017-11-14 23:13 The electrical clearance should be determined based on the measured working voltage and insulation level, and the creepage distance can be determined based on the working voltage and insulation level insulation level...

I am a student and have no experience with these industrial standards, so I am very confused. I am worried that the board I made will have an accident after it is powered on.

elvike

Prisoner's Dilemma published on 2017-11-16 10:14 Assuming that the upper tube is turned on and the lower tube is turned off, the point e of the upper tube is at the same potential as the positive bus voltage, then at this time, the voltage difference between points g and e is not the bus voltage?

The maximum voltage between ge is generally +-20V. The bus voltage you mentioned is impossible. You should understand how the driving voltage comes from. One is bootstrap, and the other is isolated DCDC