The following spreadsheet can be used for deriving the parameters of the electric powertrain based on the mechanical load characteristics (torque and velocity) and the basic characteristics of the motor:
The underlying theory is explained in the Telega Reference Manual, section “Drive power transfer equation” here:
The model is relatively simple as it is closed-form and assumes i_d=0; however, it has significant predictive power. The following example is obtained with a SunnySky X8016S 120Kv powered by Myxa at 49 V DC:
And the following is the real data obtained with Zubax Heidy with a braking resistor; pay attention to the values in the left panel:
The model is especially useful for sizing the thruster drivetrain for aeronautic applications. The dynamic parameters of the propeller can be identified with the help of Telega (with the addition of an external load cell for thrust measurement). With the known parameters of the thruster and the thrust requirements, one can apply the above model to work out the requirements for the motor controller and for the DC link power supply.
The process of running the dynamics identification script is demonstrated in the video:
