Kinco FD5 Series - Page 100

Kinco FD5 AC series servo driver user manual Chatper 7 Performance regulation
100
Generally, if the machine has more friction, the kvi should be set larger. If the entire system needs to respond quickly, kvi should
be set as small as possible . If you need to dynamically close kvi during operation, you can use the kvi close in Din function.
Note
 Kvi32=1/32 of Kvi[0]，In high resolution encoder, directly increasing the data in the
kvi[0] will lead to overshoot. At this time, you can reduce the data in kvi[0], and fine-tune
it in the kvi32
 Generally,the parameters of kpp and kvi are relative. When the kpp data is adjusted to be
much larger than the factory value, the kvi should also be appropriately increased on the
basis of the factory value.
Step 3：Adjustment of Kvi_Sum_Limit
The Kvi_sum_Limit is the maximum current limit when performing adjustment。 Usually the default value can satisfy most
applications. However, if the application system has a large resistance or the acceleration is too large, so that the actual current has
reached the Kvi_sum_limit current, and at the same time, the actual speed is far less than the target speed. The value of this
parameter should be increased. If the output current is prone to saturation, but the saturated output current will cause low
frequency oscillations, this parameter should be reduced.
The Kvi_sum_limit should be as small as possible on the basis of satisfying the applicaition. The smaller the Kvi_sum_limit value,
the shorter the adjustment time.
Step 4：Adjustment for Speed_fb_N
Feedback filter can reduce noise from the feedback path, eg, encoder resolution noise.
For different applications, the speed feedback filter can be converted to 1st and 2nd order by Speed_Mode.
1st order can reduce more noise, but produce less phase shift, allowing the higher Kvi or Kvp. 2nd order filter reduces more noise,
but also provide more phase shift, which can limit the Kvi or Kvp.
Usually, if the machine and the load use soft connection, it is recommended to use a 1st order low-pass feedback filter or turn off
the feedback filter. If the rigid connection is used or the load is too heavy, the 2nd order low-pass feedback filter could be used.
Factory default is a 2nd order low-pass feedback filter, which is suitable for most applications.
If the motor noise is too loud when adjusting the Kvi or Kvp
，
you can appropriately reduce the speed feedback filter
parameter(60F9.05). However, the velocity loop feedback filter bandwidth F must be greater than 2 times of the velocity loop
bandwidth. Otherwise, oscillation may result. Speed feedback filter bandwidth F = speed feedback filter*20+100 [HZ]
Step 5
：
Adjustment of output filter
The output filter is a first order low pass torque filter. It can reduce the high-frequency torque order output by the speed control
loop, so as to achieve the purpose of suppressing the resonance of the entire system.
When the output filter is set to 2546Hz (1DEC), it means to close the output filter control. When the system has resonance, the
user can try to adjust the DEC value of the output filter setting from small to large to reduce noise.
The output filter frequency can be calculated by the following formula:
NerFOutputT
f
_ilt_s2
1



Output_Filter_N Output filter setting(60F9.15), Unit DEC
Ts Constant 62.5us
Note
 The larger the DEC value set by the output filter, the stronger the filtering effect.

Output filter settings [Hz]=2546/[DEC]

Output filter settings [DEC]=2546/[Hz]
Step 6：Notch Filter Adjustment
A notch filter can suppress the resonance frequency by reducing the gain near the mechanical resonance.
If the resonant frequency is unknown, it can be obtained by flowing method:
Adjust the load so that the system runs in the resonance region, monitor the actual current at resonance on the oscilloscope, and
then adjust the notch filter to observe whether the resonance disappears. When the current data at resonance is collected on the
software oscilloscope, the period value of adjacent harmonics can be measured by the cursor to calculate the resonance frequency.
After collecting multiple sets of harmonic cycles to calculate the average value of the cycles, the resonant frequency can be
calculated using the average value of the cycles.