DRV8323R: estimating the total DC motor current when only knowing one phase current

Mark Pearson

Part Number: DRV8323R

Motor Guru(s),

My customer is asking:

Do you know of a way where a person could estimate the DC current by only knowing one phase current (on the source of the low-side FET)? I’ve talked with some of our motor guys, and they do this in one application, but they have current sensors on the phase wires, not on the low side of each half bridge

over 7 years ago

0 James Lockridge19 over 7 years ago

TI__Genius 14487 points

Hi Mark,

What control method are they using for their BLDC (trapezoidal, sinusoidal, etc)? Depending on the control method, there might be a good way to estimate this.

One easy way to estimate DC current is to connect all the low-side FET source pins together and measure current from a single sense resistor at the source pins to ground. Then you can average that current to estimate the DC current consumption. Is that possible in their system?

0 Mark Pearson over 7 years ago in reply to James Lockridge19

TI__Genius 12705 points

James,
The last statement is the direction they are headed...

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DRV8323R: estimating the total DC motor current when only knowing one phase current