Fuji Electric FRENIC-MEGA, Инструкция по эксплуатации

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5-159
5.2.8 d codes (Application Functions 2)
d01 to d04
d06 Speed Control 1 (Speed command filter, Speed detection filter, P (Gain) and I (Integral time))
Speed Control 1 (Output filter)
These function codes control the speed control sequence for normal operations. For application of each function code, refer
to the figure below and the subsequent descriptions.
Block diagram of the speed control sequence
„ Speed command filter (d01)
Data setting range: 0.000 to 5.000 (s)
d01 specifies a time constant determining the first order delay of the speed command filter.
Modify this data when an excessive overshoot occurs against the change of the reference speed.
Increasing the filter time constant stabilizes the reference speed and reduces overshoot against the change of the reference
speed, but it slows the response speed of the inverter.
„ Speed detection filter (d02) Data setting range: 0.000 to 0.100 (s)
d02 specifies a time constant determining the first order delay of the speed detection filter.
Modify this data when the control target (machinery) is oscillatory due to deflection of a drive belt or other causes so that
ripples (oscillatory components) are superimposed on the detected speed, causing hunting (undesirable oscillation of the
system) and blocking the PI processor gain from increasing (resulting in a slow response speed of the inverter). In addition,
if the lower encoder (PG) resolution makes the system oscillatory, try to modify this data.
Increasing the time constant stabilizes the detected speed and raises the PI processor gain even with ripples superimposed on
the detected speed. However, the speed detection itself delays, resulting in a slower speed response, larger overshoot, or
hunting.
„ P gain (d03) Data setting range: 0.1 to 200.0 (times)
I integral time (d04) Data setting range: 0.001 to 9.999 (s)
d03 and d04 specify the gain and integral time of the speed regulator (PI processor), respectively.
P gain
Definition of "P gain = 1.0" is that the torque command is 100% (100% torque output of each inverter capacity) when the
speed deviation (reference speed – detected speed) is 100% (equivalent to the maximum speed).
Determine the P gain according to moment of inertia of machinery loaded to the motor output shaft. Larger moment of
inertia needs larger P gain to keep the flat response in whole operations.
Specifying a larger P gain improves the quickness of control response, but may cause a motor speed overshooting or hunting
(undesirable oscillation of the system). Moreover, mechanical resonance or vibration sound on the machine or motor could
occur due to excessively amplified noises. If it happens, decreasing P gain will reduce the amplitude of the
resonance/vibration. A too small P gain results in a slow inverter response and a speed fluctuation in low frequency, which
may prolong the time required for stabilizing the motor speed.
Integral time
Specifying a shorter integral time shortens the time needed to compensate the speed deviation, resulting in quick response in
speed. Specify a short integral time if quick arrival to the target speed is necessary and a slight overshooting in the control is
allowed; specify a long time if any overshooting is not allowed and taking longer time is allowed.
If a mechanical resonance occurs and the motor or gears sound abnormally, setting a longer integral time can transfer the
resonance point to the low frequency zone and suppress the resonance in the high frequency zone.
„ Output Filter (d06)
Data setting range: 0.000 to 0.100 (s)
d06 specifies the time constant for the first order delay of the speed controller output filter.
Use d06 when even adjusting the P gain or integral time cannot suppress mechanical resonance such as hunting or vibration.
Generally, setting a larger value to the time constant of the output filter decreases the amplitude of resonance; however, a too
large time constant may make the system unstable.