AN1905 ST Microelectronics, Inc., AN1905 Datasheet - Page 70

• Manufacturer Part Number: AN1905
• Description: St7mc Three-phase BLDC Motor Control Software Library
• Manufacturer: ST Microelectronics, Inc.

ST7MC THREE-PHASE BLDC MOTOR CONTROL SOFTWARE LIBRARY
– With K
– At a given speed, with some load, there will be a static error with respect to the target speed;
– Contrary to proportional term adjustment, you cannot slowly increase the Ki to evaluate prop-
– When the system becomes unstable (big speed overshoot or with oscillations), stop increas-
– The appropriate value of K
– Confirm this result by trying several load conditions (if any) and slight speed variations to
– Repeat the procedure for several speeds to scan the entire speed range of the application;
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as soon as the K
erly its action: it is necessary to have dynamic conditions. This can be done by suddenly ap-
plying a given K
modifying the target speed or the load to verify that the speed settle time is correct and
there’s no or limited speed overshoot. A sharp variation as provided by dynamic brakes will
represent the most difficult conditions and is usually not very representative of a real appli-
cation. It is normally easier to work with the final application speed profile or load variations.
ing K
a reasonable phase and gain margin).
verify the system’s dynamic response. The K
best trade-off between settle time and speed overshoot, keeping in mind that it is important
to validate the lack of unstable behaviour over the whole working domain.
for large speed ratios, it is most likely that several K
best results.
i
(this is K
i
=0 and K
i limit
i
p
i
coefficient (as represented on
=x and T
value will be different from zero, the error will start to decrease.
).
s
i
=y, start the motor.
to start working with will then be K
i
can be slightly adjusted if necessary to find the
Figure
i
values will have to be used to get the
49). This can also be done by
i
= K
i limit
/ 2 (this is to provide