# Battery charging on braking

Hi friends,

I am new to this forum hope you people will help in overcomig my confusion.

I am using BLDC motor for HEV, how i can get the current coming out of statro terminals, when vehicle is in braking mode with motor behaving like generator.

Please help

Well I can’t help too much. I think what is happening when you get the motor to behave like a generator (when you ‘reverse’ it), the current that goes through the stator reverses(in a BLDC the stator is an electromagnet). At least I think thats right.

Hope you figure it out!

Thanks Gray,
Ya I got your point, Its the generator action of motor which gives us stator current and as far as i know, i think the torque applied will decide the quantity of current generated. But, how can we estimate the current generated? any specific relation.

Okay, It’s a little complicated and requires math…

Torque is measured in Newton meters (1 newton meter ≈ .737 foot pounds). Current is measured in amperes and is a factor of power ( watts = volts ∙ amps).
Rotational speed is measured in radians per second ( 314 rad/s ≈ 3,000 rpm if my calculations are correct).

I found an equation that will help you with this:
P = T ∙ W (P is power, T is the torque, and W is the rotaional speed)

If you know the torque, and the rotational speed, you can find the power output ( you will have to convert rpm to rad/s by dividing your rpm by 60 and multiplying it by 2π).

If that works out, you now know your power output. If you know the voltage produced (it should be the same as the motor uses), then you can find the current. All that you need to do is take your watts (power) and divide it by your voltage. Then you should get the current (amps).

[QUOTE=Surekha;8844]Hi friends,

I am new to this forum hope you people will help in overcomig my confusion.

I am using BLDC motor for HEV, how i can get the current coming out of statro terminals, when vehicle is in braking mode with motor behaving like generator.

Please help[/QUOTE]

i want to help you, but i dont know:cheer2: