NXP Semiconductors MCUXpresso, User Manual

Page: 36 / 50

Figure 25. Encoder direction—wrong direction
8.10 Alignment tuning
For the alignment parameters, navigate to the “Parameters” MCAT tab. The alignment procedure sets the rotor to an accurate
initial position and enables you to apply full start-up torque to the motor. A correct initial position is needed mainly for high start-up
loads (compressors, washers, and so on). The aim of the alignment is to have the rotor in a stable position, without any oscillations
before the startup.
1. The alignment voltage is the value applied to the d-axis during the alignment. Increase this value for a higher shaft load.
2. The alignment duration expresses the time when the alignment routine is called. Tune this parameter to eliminate rotor
oscillations or movement at the end of the alignment process.
8.11 Current loop tuning
The parameters for the current D, Q, and PI controllers are fully calculated using the motor parameters and no action is required
in this mode. If the calculated loop parameters do not correspond to the required response, the bandwidth and attenuation
parameters can be tuned.
1. Lock the motor shaft.
2. Set the required loop bandwidth and attenuation and click the “Update target” button in the “Current loop” tab. The tuning
loop bandwidth parameter defines how fast the loop response is whilst the tuning loop attenuation parameter defines the
actual quantity overshoot magnitude.
3. Select the “Current Controller Id” recorder.
4. Select the “Current Control” in the FreeMASTER project tree, select "CURRENT_FOC" in "M1 MCAT Control" variable.
Set the “M1 MCAT Iq required” variable to a very low value (for example 0.01), and set the required step in “M1 MCAT Id
required”. The control loop response is shown in the recorder.
5. Tune the loop bandwidth and attenuation until you achieve the required response. The example waveforms show the
correct and incorrect settings of the current loop parameters:
• The loop bandwidth is low (110 Hz) and the settling time of the Id current is long ( Figure 26 ).
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 36 / 50