Winco DGC-2020 - Manual (Page 334)

C-4 DGC-2020 Tuning PID Settings 9400200990 Rev K
and the speed it is trying to reach. The important thing is that the generator’s output behaves in a stable
manner. If the system is unstable, lower KP and repeat.
Repeat this procedure, raising KP until the system is unstable, and then lower it to half the value where
instability is first attained.
If it is not possible to obtain stable speed operation, it may be necessary to reduce the control gains in the
governor that has its analog bias input driven by the LSM-2020.
KI - Integral Gain
Set the initial value of KI to be a tenth of the value set for KP.
Each time KI is set, manually displace the governor lever or change the speed trim set point and verify
that control is regained in a stable manner. If the system is not stable, lower KI and repeat.
Repeat this procedure, raising KI until the system is unstable, and then lower it to half the value where
instability is first attained.
KD - Derivative Gain
If the performance with KP and KI alone is satisfactory, you may stop here. Otherwise, KD, the derivative
controller gain, can be used in conjunction with TD, the noise filter constant, to reduce overshoot obtained
with the PI control. Setting KD and TD is an iterative process. Start with small values of KD such as 0.1 or
half the KI value, whichever is less.
TD is the constant of the low pass filter which filters the controller input if high frequency interference
presents a problem when derivative control is employed. TD ranges from 0 to 1. TD=0 is no filtering.
TD=1 is heaviest filtering.
Tuning of KD can be achieved through the following steps. First set TD=0 to eliminate filtering. Raise
speed KD and check for stability. Each time KD is raised, manually displace the governor lever or change
the speed trim set point and see that control is regained in a stable manner. Raise KD until the system is
unstable, and then lower it to half the value where instability if first attained.
If high frequency noise seems to be entering the system, set TD to 0.001 and see if the noise induced
behavior is reduced. Raise TD until desired reduction of noise behavior is achieved. Once TD has been
set, tune KD again. TD ranges from 0 to 1 with an increment of 0.001. TD=0 is no filtering, TD=1 is
heaviest filtering. If noise again appears to be a problem, adjust TD until desired behavior is achieved,
and then retune KD.
kW Load Controller Tuning Procedure
Once desired voltage and speed controller performance is obtained, the kW load controller can be tuned.
Set all gains in kW load controller to 0.
KP - Proportional Gain
Set an initial value of 1 for KP.
Close the breaker onto a load. Parallel a second generator with the unit being tuned and check for stable
load sharing. Then open the generator breaker on the second generator and check that the unit being
tuned is still stable. Since KI is zero at this point, there may be some small error in the load sharing. The
important thing is that stable load sharing is achieved.
Raise KP and repeat the test until unstable operation occurs. Lower KP to half the value where unstable
operation was first attained.
If it is not possible to obtain stable kW operation, it may be necessary to reduce the control gains in the
governor that has its analog bias input driven by the LSM-2020.
KI - Integral Gain
Set the initial value of KI to be a tenth of the value set for KP.
Each time KI is set, parallel a second generator with the unit being tuned, and check for stable load
sharing then open the generator breaker on the second generator and check that the unit being tuned is
still stable. If the system is not stable, lower KI and repeat the test.
Repeat this procedure, raising KI until the system is unstable, and then lower it to half the value where
instability is first attained.