ABB ACQ80, Firmware Manual

Page: 134 / 390

134 Parameters
25.04 Speed derivation
time
Defines the derivation time of the speed
controller.
Derivative action boosts the controller output if
the error value changes. The longer the
derivation time, the more the speed controller
output is boosted during the change. If the
derivation time is set to zero, the controller
works as a PI controller, otherwise as a PID
controller. The derivation makes the control
more responsive for disturbances. For simple
applications, derivative time is not normally
required and should be left at zero.
The speed error derivative must be filtered with a
low pass filter to eliminate disturbances.
The figure below shows the speed controller
output after an error step when the error remains
constant.
Note: ABB recommends not to change the
default value. This can impact the MPPT
efficiency.
0.000
0.000…10.000 s Derivation time for speed controller. 1000 = 1
No. Name/Value Description Def/
FbEq16
Gain = K
p
= 1
T
I
= Integration time > 0
T
D
= Derivation time > 0
T
s
= Sample time period = 250 µs
Δ e = Error value change between two samples
K
p
× T
D
×
Δ
e
T
s
Controller output
e = Error value
Error value
Time
T
I
K
p
× e
K
p
× e
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