DRV10975: DRV10975

Hello Hiep,

If you do not have your motors parameters or if you dont think they are correct you can measure both the motor phase resistance and the BEMF constant manually using a multimeter and a scope.

To measure motor phase resistance you can take a motor phase to positive probe and another phase to the negative probe of the multimeter, this will give you the motor phase resistance for two of the motors phases so you have to divide this number by two in order to get the correct value.

To measure the BEMF constant Kt, you will need to use a scope, again connect one of the probes to one of the motors leads and the ground lead to another motor phase and spin the motor manually. This should yield a sinusoidal waveform on the scope, from there you need to measure the voltage and the period between the sinusoidal signals. Divide the peak to peak amplitude by 2 and used that for Ep and Te is the period of the signal (refer to the image below) this should give you a Kt value you can use. The image is from the DRV10975 tuning guide which you can view here: https://www.ti.com/lit/ug/slou395d/slou395d.pdf

Keep in mind that Kt can sometimes vary when there is a load on the motor or not so this is not a tried and true method but will give you a good starting point to help tune your system.

Best,

Isaac

Hey Hiep,

The phase resistance can be found on line item 23 on the datasheet, 0.37 ～ 0.49 Ω.

Unfortunately I did not see a BEMF value on the datasheet which is sometimes not included in the datasheet so you will have to follow the method I sent above to measure the BEMF and go from there.

Best,

Isaac