NXP Semiconductors MCUXpresso, Руководство пользователя

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The ω
m
character in the equation is the mechanical speed. The mechanical parameter identification software uses the torque
profile. The loading torque is (for simplicity reasons) said to be 0 during the whole measurement. Only the friction and the
motor-generated torque are considered. During the first phase of measurement, the constant torque
T
meas
is applied and the
motor accelerates to 50 % of its nominal speed in time t
1
. These integrals are calculated during the period from t
0
(the speed
estimation is accurate enough) to t
1
:
During the second phase, the rotor decelerates freely with no generated torque, only by friction. This enables you to simply
measure the mechanical time constant
τ
m
=J/B
as the time in which the rotor decelerates from its original value by 63 %.
The final mechanical parameter estimation can be calculated by integrating:
Te moment of inertia is:
The viscous friction is then derived from the relation between the mechanical time constant and the moment of inertia. To use the
mechanical parameters measurement, the current control loop bandwidth
f
0,Current
, the speed control loop bandwidth
f
0,Speed
, and
the mechanical parameters measurement torque
Trq
m
must be set.
NXP Semiconductors
Remote control using FreeMASTER
MCUXpresso SDK Field-Oriented Control (FOC) of 3-Phase PMSM and BLDC motors, Rev. 0, 01/2022
User Guide 31 / 50