Air core inductor selection for double pulse test

PowerEngineer

Hi, in the document that outlines the equipment necessary for conducting double pulse test, we would need an air core inductor. Is there a document that tells how to select one? or does the SpeedVal kit come with an air core inductor?

Thanks

Forum_Moderator

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AAnders

Hello,

There is an air core inductor that was developed by Bourns as part of the SpeedVal Kit platform. You can purchase it separately: https://www.arrow.com/en/products/bs501145t-04/bourns?q=BS501145T-04

However, you can also build your own in the lab fairly easily. A simple method is to wrap ~18-22 AWG wire (magnet wire or hook-up wire) around a 4-6 inch diameter PVC or cardboard tube. Use a single layer, and provide turn-to-turn spacing of approximately the diameter of the wire to reduce the shunt capacitance of the inductor which can introduce extra ringing into the system.

In terms of selecting the inductance value, you need to consider the operating point you will be testing at. It is best to target total on-time of the MOSFET to be between 1 and 10us for the complete DPT to provide good controllability of the gate timing and minimize self-heating. You can then design an appropriate inductor based on V=L*di*dt where V is the bus voltage, di = the test current, and dt is between 1 and 10us. We typically use inductors in the range of 30-150uH.

The SpeedVal Kit power daughter card is set up for power testing by default. To get better accuracy for DPT, follow the instructions in the user guide to adjust the shunt resistors or to use the CT. Maximum pulse currents are limited to 70-80A in the DPT configuration.

Please let me know if you have any additional questions.

Thanks,

Adam

TBhatia

Hi, I hope that this answered your question. I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.