Slip controller
In case of V/f characteristic control with feedback (VFC closed loop), the slip is calculated and injected by the slip controller. The default setting of the slip controller provides robustness and moderate dynamics.
Preconditions
In 0x2C00 (P300.00), the motor control type "V/f characteristic control (VFC closed loop) [7]" is selected and configured. For details, see chapter "V/f characteristic control for asynchronous motor (VFC closed loop)".
Details
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The slip controller is designed as a PI controller.
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In order to improve the response to setpoint changes, the setpoint speed or setpoint frequency is added as a feedforward control value to the output (correcting variable) of the slip controller.
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With the setting 0x2B14:003 = 0 Hz, the slip controller is deactivated.
Controller gain Vp
The gain setting range of the slip controller Vp 0x2B14:001, which causes a stable operating power, mainly depends on the resolution of the speed sensor. There is a direct relation between the encoder resolution and the gain:
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The higher the encoder resolution, the higher the gain can be set. The following table contains the required gains for the encoder with standard encoder increments:
|
Encoder increment [increments / revolution]
|
recommended
|
|
8
|
0.06
|
|
64
|
0.31
|
|
100
|
0.47
|
|
120
|
0.57
|
|
128
|
0.6
|
|
256
|
0.77
|
|
386
|
0.98
|
|
512
|
1.18
|
|
640
|
1.38
|
|
768
|
1.59
|
|
896
|
1.79
|
|
1014
|
2
|
|
1536
|
2.81
|
|
2048
|
3.63
|
|
3072
|
5.26
|
|
4096
|
6.9
|
Parameter