NXP Semiconductors MCUXpresso, Руководство пользователя

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Table 9. MCAT motor parameters (continued)
Parameter Units Description Typical range
Uph nom [V] Motor nominal phase voltage 10-300
N nom [rpm] Motor nominal speed 1000-2000
4. Set the hardware scales—the modification of these two fields is not required when a reference to the standard power stage
board is used. These scales express the maximum measurable current and voltage analog quantities.
5. Check the fault limits—these fields are calculated using the motor parameters and hardware scales (see Table 10 ).
Table 10. Fault limits
Parameter Units Description Typical range
U DCB trip [V] Voltage value at which
the external braking resistor
switch turns on U DCB Over ~ U DCB max
U DCB under [V] Trigger value at which the
undervoltage fault is detected 0 ~ U DCB Over
U DCB over [V] Trigger value at which the
overvoltage fault is detected U DCB Under ~ U max
N over [rpm] Trigger value at which the
overspeed fault is detected N nom ~ N max
N min [rpm] Minimal actual speed value for
the sensorless control (0.05~0.2) *N max
6. Check the application scales—these fields are calculated using the motor parameters and hardware scales.
Table 11. Application scales
Parameter Units Description Typical range
N max [rpm] Speed scale >1.1 * N nom
E block [V] BEMF scale ke* Nmax
kt [Nm/A] Motor torque constant -
7. Check the alignment parameters—these fields are calculated using the motor parameters and hardware scales. The
parameters express the required voltage value applied to the motor during the rotor alignment and its duration.
8. Click the “Store data” button to save the modified parameters into the inner file.
8.8 Control structure modes
1. Select the scalar control in the "M1 MCAT Control" FreeMASTER variable watch.
2. Set the "M1 Application Switch" variable to "ON". The application state changes to “RUN”.
3. Set the required frequency value in the “M1 Scalar Freq Required” variable; for example, 15 Hz in the “Scalar & Voltage
Control” FreeMASTER project tree. The motor starts running.
4. Select the “Phase Currents” recorder from the “Scalar & Voltage Control” FreeMASTER project tree.
5. The optimal ratio for the V/Hz profile can be found by changing the V/Hz factor directly using the “M1 V/Hz factor” variable.
The shape of the motor currents should be close to a sinusoidal shape ( Figure 22 ). Use the following equation for calculation
V/Hz factor:
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 33 / 50