Parameters: 14-** Special Functions; Inverter Switching; Mains On/Off - Danfoss VLT AutomationDrive FC 360 Programming Manual

Parameter Descriptions

4.13 Parameters: 14-** Special Functions

4.13.1 14-0* Inverter Switching

14-01 Switching Frequency
Option: Function:
Select the inverter switching frequency. Changing
the switching frequency can help to reduce
acoustic noise from the motor.
[0] Ran3 3 kHz true random PWM (white noise
modulation).
[1] Ran5 5 kHz true ramdom PWM (white noise
modulation).
[2] 2.0 kHz
[3] 3.0 kHz
[4] 4.0 kHz
[5] 5.0 kHz
[6] 6.0 kHz
[7] 8.0 kHz
[8] 10.0 kHz
[9] 12.0 kHz
[10] 16.0 kHz
14-03 Overmodulation
Option: Function:
[0] Off Select [0] Off for no overmodulation of the output
voltage to avoid torque ripple on the motor shaft. This
feature may be useful for applications such as grinding
machines.
[1] On Select [1] On to enable the overmodulation function
*
for the output voltage. This is the right choice when it
is required that the output voltage is higher than 95%
of the input voltage (typical when running over-
synchronously). The output voltage is increased
according to the degree of overmodulation.
NOTICE
Overmodulation leads to increased torque
ripple as harmonics are increased.
14-07 Dead Time Compensation Level
Range:
Size related [0 - 100 ]
*
14-08 Damping Gain Factor
Range: Function:
96 % [0 - 100 %] Damping factor for DC-link voltage compen-
*
sation.
14-09 Dead Time Bias Current Level
Range:
Size related [0 - 100 %]
*
MG06C402
Programming Guide

4.13.2 14-1* Mains On/Off

Parameters for configuring mains failure monitoring and
handling. If a mains failure appears, the frequency
converter tries to continue in a controlled way until the
power in the DC link has been exhausted.
14-10 Mains Failure
Option:
[0] No
function
*
[1] Ctrl.
ramp-
down
Function:
Function:
Danfoss A/S © Rev. 2014-03-31 All rights reserved.
Function:
NOTICE
Parameter 14-10 Mains Failure cannot be
changed while motor is running.
Parameter 14-10 Mains Failure is typically used
where very short mains interruptions (voltage
dips) are present. At 100% load and a short
voltage interruption, the DC voltage on the main
capacitors drops quickly. For larger frequency
converters it only takes a few milliseconds before
the DC level is down to about 373 V DC and the
IGBTs cut off and loses the control over the
motor. When mains is restored, and the IGBTs
start again, the output frequency and voltage
vector does not correspond to the speed/
frequency of the motor, and the result is normally
an overvoltage or overcurrent, mostly resulting in
a trip lock. Parameter 14-10 Mains Failure can be
programmed to avoid this situation.
Select the function to which the frequency
converter must act when the threshold in
14-11 Mains Voltage at Mains Fault has been
reached.
The frequency converter does not compensate for
a mains interruption. The voltage on the DC-link
drops quickly and motor control will be lost
within milliseconds to seconds. Trip lock is the
result.
The frequency converter remains control of the
motor and does a controlled ramp-down from
parameter 14-11 Mains Voltage at Mains Fault level.
If parameter 2-10 Brake Function is [0] Off or [2] AC
brake, the ramp will follow the Over Voltage
Ramping. If parameter 2-10 Brake Function is [1]
Resistor Brake, the ramp follows the setting in
parameter 3-81 Quick Stop Ramp Time. This
selection is particularly useful in pump
applications, where the inertia is low and the
friction is high. When mains is restored, the
output frequency ramps the motor up to the
reference speed (if the mains interruption is
prolonged, the controlled ramp down might take
the output frequency all the way down to 0 RPM,
and when the mains is restored, the application is
ramped up from 0 RPM to the previous reference
speed via the normal ramp up). If the energy in
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