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Shunt resistor replacement and too high motor current

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lacondro
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Shunt resistor replacement and too high motor current

Hi, I am trying to develop my own 75V 100A vesc based on 75300 hardware.

My first prototype runs motor pretty well, but the phase current looks a bit noisy.

So I replaced shunt resistor 0.0005R →0.005R as I read on one article how to reduce the current noise.

and also I modified to source code to

#define CURRENT_SHUNT_RES 0.005 as well.

But the strange thing is that the measured motor current on VESC TOOL is about 10 times higher than before.

The input battery current is similar as before.

The parameter CURRENT_SHUNT_RES is used in FAC_CURRENT calculation as below,

#define FAC_CURRENT ((V_REG / 4095.0) / (CURRENT_SHUNT_RES * CURRENT_AMP_GAIN)) at conf_general.h

maybe this can affect the motor current to high?

I really want to know can I fix this issue.

Thank you. 

 

NOAI
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Change ''CURRENT AMP GAIN'' accordingly.

lacondro
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Thanks for the reply.

but I am using INA240A1 which has a current gain of 20V/V, do you mean I have to change CURRENT_AMP_GAIN to 2 instead?