Other Parts Discussed in Thread: DRV8329
Tool/software:
Dear TI experts,
We measured BEMF as recommended in the MSPM0 Sensorless FOC Tuning Guide (Rev. B).
We have some questions during the process.
As mentioned in the tuning guide, we connected the shaft of the motor we wanted to measure BEMF to with another motor without powering it and let it rotate.
As a result, the result came out like the waveform.
I take "measure the voltage across any two phases of the motor" to mean measure the line-to-line voltage, but just in case, I measured the voltage of one phase as well.
Yellow is the voltage across one phase (Va) and blue is the line-to-line voltage (Va-Vb).
Based on the result, if Ep = 1150 and Tp = 0.028479, and calculate,
Bemf Constant Ke = 1150* 0.028479 /1.732 = 18.91,
BEMF Constant = 18.91*60/5(pole pairs) = 226.92
Since mtrBEMFConst in the System Configuration Page as Ke × 10,
mtrBEMFConst = 226.92 * 10 = 2269.2 is obtained.
It is about 10 times higher than the mtrBEMFConst value in the example code(mspm0 sdk_2_03_00_07\examples\nortos\LP MSPM0G3507\motor_control_pmsm_sensorless_foc\sensorless-foc DRV8329).
Is this calculation correct?
