Lenze i950 Series, Manual, Page: 267 / 500

13.6.5.2 Current controller
The current controller consists of a direct-axis current controller and a cross current controller
which are both parameterised identically. The direct-axis current controller controls the field-
producing current (D current). The cross current controller controls the torque-producing cur-
rent (Q current).
For a servo control, the current controller should always be optimised if a motor
of another manufacturer with unknown motor data is used! For a V/f character-
istic control, the current controller only has to be optimised if voltage vector
control Activate voltage vector control (Imin controller) is used, or if DC-injec-
tion braking or the flying restart process is activated.
Automatically calculated settings for the current controller
If one of the values calculated exceeds the upper object limit, the value is limi-
ted to the limit value.
There is a coupling between the two control loops (direct-axis current controller, cross current
controller) which makes every actuation of a controller occur as fault in the control loop of the
other controller. This coupling can be compensated by activating the current controller feed-
forward control via object 0x2941 .
For the automatic calculation of the two controller parameters (gain and reset time), the
"Calc. current contr. param." function is provided via object 0x2822:013. The calculating func-
tion is based on the stator resistance 0x2C01:002 and the stator leakage inductance
0x2C01:003 . Thus, these motor parameters must be parameterised before, e. g. by entering
the data sheet values manually. Subsequently, the calculated controller parameters can be
optimised by means of an experimental adjustment. The procedure is described in the follow-
ing section Manual "current pulse" test mode .
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305
Equation for calculating the gain of the synchronous motor
=
ss
p
Totzeit
L
V
T
Equation for calculating the reset time of the synchronous motor
=
ss
n
s
L
T
R
Parameter Symbol Description Dimension unit
0x2942:001 V
p
Current controller gain V/A
0x2C01:003 L
ss
Stator leakage inductance H
- T
Dead time
Equivalent time constant for the
analog detection and scanning =
0.00009375 s (93.75 µs) s
0x2942:002 T
n
Current controller reset time s
0x2C01:002 R
s
Stator resistance (value at 20° C) Ω
Equation for calculating the gain of the asynchronous motor
s × ×
= »
s ss
p
Totzeit Totzeit
L 2 L
V
T T
Configuring the motor control
Options for optimising the control loops
Motor control settings
267