Use a single current sensor?

[MTappen]

I am working on a project with stepper motors. I am using an ACS Hall effect sensor for current sensing. I was planning on two sensors inline with the motor coils.

Could I just put a single sensor inline with the driver power supply? There would be some extra code to calculate actual winding current (if necessary), but would there be other disadvantages?

Thanks!

[Valentine]

@MTappen

put a single sensor inline with the driver power supply

I believe SimpleFOC supports only two or three inline current sensors. The two current estimation is not as good as three, but the estimation algorithm it’s built into the library.

Doing one inline sensor with the driver motor voltage input (high side I assume???) is probably possible (doubtful ???) but you need to re-write the algorithm yourself.

Some good discussion here:

Advice on Current Sensing for new board design

Hi Antun, Be careful here, with only one shunt resistor you will be screwed… In the tab below you will find the current you will sample with the single shunt topology depending of the state of the inverter when you sample the voltage drop across the shunt resistor. [current_single_shunt] With this approach you will never know the total current flowing through the 3 coil of the motor because the coil will never be (hopefully) connected to the shunt resistor at the same time. So you will be u…

Cheers,
Valentine