Lenze 8400 - Manual (Page 230)

5 Motor control (MCTRL)
5.9 Servo control (SC)
230
Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05
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5.9.4.2 Optimise speed controller
The speed controller is in the form of a PID controller with an additional differential speed-setpoint
gain. For optimum behaviour, the PID speed controller has to be optimised and the overall mass
inertia of the drive train has to be determined.
• In the Lenze setting, the configuration of the speed controller provides robustness and
moderate dynamics.
Speed controller gain Vp
The gain Vp (
C00070/2 ) of the speed controller is defined in a scaled representation which enables
a comparable parameterisation almost independent of the power of the motor or inverter. Here, the
speed input difference of the controller is scaled to the rated motor speed whereas the output
torque refers to the rated motor torque. A gain of 10 means that a speed difference of 1 % is gained
through the P component with 10 % torque.
If the rated data of the motor and the mass inertia of the drive system are known, we recommend
the following setting:
[5-21] Recommendation for the setting of the gain of the speed controller
If the mass inertia of the drive is unknown, the optimisation can be achieved as follows:
1. Specify speed setpoint.
2. Increase Vp (
C00070/2 ) until the drive is unstable (observe motor noise).
3. Reduce Vp ( C00070/2 ) until the drive runs stable again.
4. Reduce Vp ( C00070/2 ) to approx. half the value.
Parameter Info Lenze setting
Value Unit
C00070/2 SC: Vp speed controller 6.00
C00071/2 SC: Ti speed controller 50.0 ms
C00072 SC: Tdn speed controller 0.00 ms
V
P
= Gain of the speed controller ( C00070/1 )
T
M
= Time constant for the acceleration of the motor
M
N
= Rated motor torque
n
N
= Rated motor speed
J
drive, total
= Total moment of inertia of the drive
V
P
1.5 ... 3
T
M
s [ ]
0.01 s [ ]
------------------- ⋅ ≈
T
M
s [ ]
2 π n
N
rpm [ ] ⋅ ⋅
M
N
Nm [ ] 60 ⋅
-------------------------------------- J
Drive, total
kgm
2
[ ] ⋅ =
M
N
Nm [ ]
P
N
W [ ] 60 ⋅
2 π n
N
rpm [ ] ⋅ ⋅
-------------------------------------- =