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cross mob
Level 1
Level 1
First question asked
Hi all

I have a design that drives two 12v dc motors using the reference design set up for a bi-directional h bridge. This has worked well for about a year.

We now need to drive a 28v dc version of the motor and have been experiencing some issues. The motors seem to judder depending on the speed they are running at. i.e they could be fine at 25% speed then judder at about 50% to 75% speed and then be fine to 100% speed.

The original design used the BTN8982A device which I understand from the data sheet may not work correctly above 18V so have switched to the IFX007 which states it should be good up to 40v, but still have the same proiblem.

I have tried different values of DC-Link capacitor thinking this could be causing it but this doesn't seem to make much difference except for making it worse if I make it too big.

Can anyone offer any ideas as to why it may be juddering? I have also tried on 24V and it does the same thing.

1 Reply
First like received First solution authored 25 replies posted
Thanks very much for your interest.

For BTN8982TA: The parameters specified in our datasheet might have deviation when the voltage is higher than 18V.
For IFX007T: According to industrial standard, the parameters are only specified at 24V. It can also have deviations when the VS is 28V.

If you could provide some measurement result(e.g. screenshot from oscilloscope), we can help you better. It is difficult to locate the problem only based on your rough description.