Function Application
‑589‑
For a load running at an extremely low speed (for example, a milling machine running
at 0.01 Hz), ensure smooth running by increasing the speed loop gains, especially the
integral gain (by increasing the value of F2‑00 and reducing the value of F2‑01).
Note
In scenarios with poor encoder feedback signals, the speed loop gains cannot be too high.
Otherwise, the dynamic response speed of the system is affected. In this case, first take
measures to improve the quality of encoder feedback signals (for example, separate power
cables of the motor from signal cables of the encoder, and ensure good grounding of the
system). Otherwise, directly reducing the speed loop gains will slow down dynamic re‑
sponse of the system, degrading the system operation performance.
Current loop settings
Current loop parameters can be automatically obtained after auto‑tuning on all
parameters of the asynchronous motor and generally do not need to be modified.
However, you can fine tune these parameters in the following conditions:
When a motor running in FVC mode oscillates or generates abnormal noise, and this
problem persists after values of the speed loop parameters are reduced, moderately
reduce values of the current loop parameters (F2‑13, F2‑14, F2‑15, and F2‑16).
If the system requires a low overshoot, values of the speed loop parameters cannot
be too small. In this case, if the motor oscillates or generates abnormal noise when
running in FVC mode, moderately reduce values of the current loop parameters (F2‑
13, F2‑14, F2‑15, and F2‑16).
Solutions to exceptions during high-speed running in FVC
FVC oscillation or running exceptions may occur when a motor runs at a high
frequency (for example, above 200 Hz). In this case, use the V/f control mode at the
same frequency and check whether the feedback frequency (U0‑29) is the same as the
frequency reference. If there is a large difference (greater than 4 Hz) between the two
frequencies, the cause may be encoder signal distortion (non‑orthogonal or abnormal
duty cycle) or signal filtering on the PG card. Take the following measures:
Replace the encoder. Check whether the original encoder is damaged or installed
incorrectly, and whether the encoder model supports the current pulse frequency.
If measures have been taken to prevent encoder signal distortion during high‑speed
operation, high filter capacitance of the PG card may cause a failure in receiving
signals. In this case, set F1‑29 properly for PG signal filtering.
Changing acceleration/deceleration time in FVC control mode
During rapid acceleration/deceleration, the actual acceleration/deceleration time is
longer than the preset value. To shorten the acceleration/deceleration time, take the
following measures:
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