RC Snubber for Motor Drivers

Shivam Gupta

Hi,

I am doing the RC Snubber Design for a 3 phase Inverter.

In each Leg of Inverter, I have 4 Mosfets in parallel. Can anyone suggest me which one is the best approach and why, out of these 2 which I have listed below:

1. Approach 1: RC snubber for each Mosfet.

2. Approach 2: RC snubber for one topological Mosfet.

over 1 year ago

0 Yara Al Shami over 1 year ago

TI__Genius 15635 points

Hi Shivam,

This FAQ mentions

https://e2e.ti.com/support/motor-drivers-group/motor-drivers/f/motor-drivers-forum/991693/faq-proper-rc-snubber-design-for-motor-drivers?tisearch=e2e-sitesearch&keymatch=rc%20snubber#

"In order to mitigate the ringing at the phase output, a simple resistor-capacitor (R-C) snubber circuit can be used to “snub”, or dampen the oscillations. By removing the oscillations, this will reduce potential EMI and increase the longevity of the MOSFETs by reducing voltage overstress. The R-C snubber is placed in parallel as close as possible to each MOSFET’s drain and source connections."

If you want to maximize the positive side effects of an RC snubber it would be best to follow what was advised in the FAQ hence Approach 1 would be the best option.

In Approach 2 the only MOSFETs that would effectively have their oscillations dampened would be only the ones that have an RC snubber.

Regards,

Yara

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RC Snubber for Motor Drivers