How can reduce starting Surge current or voltage from BLDC

[pranay.upadhyay]

Hello,

We are driving BLDC motor but when we try to stop and start repeatedly then MODFET blows. Normally it is able to run on load only problem comes when we try to run-stop repetedly.

Please help how can we handle this using Firmware change or through hardware ?

Please give some suggestion.

-Pranay

 

[bubulescu]

Re: How can reduce starting Surge current or voltage from BL

Hello,

The simplest solution would be an NTC, but a more elegant one would be a soft start, achievable with a simple RC in the feedback loop, with a time constant small enough not to wait to much for steady state. Or, you could implement a current limit, or a di/dt limit right in the (half-)bridge. There may be other solutions, as well. These come to mind, for now.

Good luck!

 

[dgaumond]

Re: How can reduce starting Surge current or voltage from BL

What is your brake method :

best i think it was 3 low side mosfet short motor


You can try to split the on pulse of PWM

**broken link removed**

 

[bobcat1]

Re: How can reduce starting Surge current or voltage from BL

Hi

You will need to ramp up and ramp down the voltage to the motor - e.g accelerate speed (start with the lowest speed the can drive the motor and slowly increase it to the full speed) and decelerate - do the same when you go from hi speed to low speed


All the best

Bobi