Firmware 03.00 - DMS EN 5.0 - 07/2009
L
79
8400 BaseLine D | Software Manual
Motor control (MCTRL)
Selection of the operating mode
Subsequent optimisation of the V/f characteristic control
The V/f characteristic control is generally ready for service. The options to subsequently
adapt the V/f characteristic control is to adapt the drive behaviour.
Adaptation of the characteristic
– Each of the three characteristic shapes can be adapted to different load profiles or
motors via several parameters, see e.g.
min
boost.
Adaptation of the drive behaviour
– Limitation of the maximum current
by a current controller (e.g. to prevent the
motor from stalling or to limit to the maximum permissible motor current)
– Adaptation of the field frequency by a load-dependent slip compensation
(improved speed accuracy for systems without feedback)
Only the following drive behaviour requires an optimisation of the V/f characteristic
control:
Drive behaviour
Remedy
Bad smooth running with low speeds, especially in case
of operation with long motor cable
Carry out motor identification
Problems in case of high starting duty (great mass
inertia)
Adapt V
min
boost
• Set the code so that a 0.8 ... 1-fold rated motor current
flows with a controller enabled and 5 ... 10% of the
rated speed.
The drive does not follow the speed setpoint.
The current controller intervenes in the set field
frequency to limit the controller output current to the
maximum current (C0022, C0023). Therefore
• increase acceleration time / deceleration time
• Consider a sufficient magnetising time of the motor.
Depending on the motor power the magnetising time
amounts to 0.1 ... 2 s
• increase permissible maximum current (in motor
mode, in generator mode)
For operation with
= 6:
Insufficient speed constancy at high load (setpoint and
motor speed are not proportional any more)
• Increase slip compensation
.
Important: unstable drive due to overcompensation!
• If cyclic load impulses (e.g. centrifugal pump) occur, a
smooth motor characteristic is achieved by smaller
values in
(possibly negative values)
Error messages "Peak current limitation clamp" (FCL),
controller cannot follow dynamic processes, i.e.
acceleration or deceleration times are too short
regarding the load conditions
• Increase the gain of the I
max
controller
• Reduce the integral-action time of the I
max
controller
• Increase the acceleration time
• Increase the deceleration time