Parameters: 14-** Special Functions; Inverter Switching; Switching Frequency; Overmodulation - Danfoss VLT AutomationDrive Programming Manual

Parameter Descriptions

3.15 Parameters: 14-** Special Functions

3.15.1 14-0* Inverter Switching

14-00 Switching Pattern
Option: Function:
[0] 60 AVM Select the switching pattern: 60° AVM or SFAVM.
*
[1] SFAVM
*
NOTE!
The output frequency value of the Adjustable frequency
drive must never exceed 1/10 of the switching frequency.
When the motor is running, adjust the switching frequency
in 4-11 Motor Speed Low Limit [RPM] until the motor is as
noiseless as possible. See also 14-00 Switching Pattern and
the section Special Conditions in the VLT AutomationDrive
Design Guide, MG33BXYY.

14-01 Switching Frequency

Select the inverter switching frequency. Changing the switching
frequency can help to reduce acoustic noise from the motor.
Default depend on power size.
Option:
[0] 1.0 kHz
[1] 1.5 kHz
[2] 2.0 kHz
[3] 2.5 kHz
[4] 3.0 kHz
[5] 3.5 kHz
[6] 4.0 kHz
[7] 5.0 kHz
*
[8] 6.0 kHz
[9] 7.0 kHz
[10] 8.0 kHz
[11] 10.0 kHz
[12] 12.0 kHz
[13] 14.0 kHz
[14] 16.0 kHz
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FC 300 Programming Guide
Function:
Default switching frequency for
500–1,600 hp [355–1,200 kW], 690
V
Default switching frequency for
350–1,075 hp [250–800 kW], 400 V
and 50–400 hp [37–315 kW], 690 V
Default switching frequency for
25–50 hp [18.5–37 kW], 200 V and
50–300 hp [37–200 kW], 400 V
Default switching frequency for
7.5–20 hp [5.5–15 kW], 200 V and
15–40 hp [11–30 kW], 400 V
Default switching frequency for
0.34 - 4.96 kW hp [0.25–3.7 kW],
200 V and 0.496–10 hp [0.37–7.5
kW], 400 V
®
MG33MD22 - VLT is a registered Danfoss trademark
NOTE!
The output frequency value of the Adjustable frequency
drive must never exceed 1/10 of the switching frequency.
When the motor is running, adjust the switching frequency
in 4-11 Motor Speed Low Limit [RPM] until the motor is as
noiseless as possible. See also 14-00 Switching Pattern and
the section Special conditions in the VLT AutomationDrive
Design Guide, MG33BXYY.
NOTE!
Switching frequencies higher than 5.0 kHz lead to
automatic derating of the maximum output of the
Adjustable frequency drive.

14-03 Overmodulation

Option: Function:
[0] Off Select Off [0] for no overmodulation of the output
voltage, in order to avoid torque ripple on the
motor shaft. This feature may be useful for
applications such as grinding machines.
[1] On Select On [1] 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 oversynchronously). The output
voltage is increased according to the degree of
overmodulation.
Overmodulation leads to increased torque ripple
as harmonics are increased.
Control in FLUX mode provides an output current
of up to 98% of the input current, regardless of
14-03 Overmodulation.
[2] Optimal
14-04 PWM Random
Option: Function:
[0] Off No change of the acoustic motor switching noise.
*
[1] On Transforms the acoustic motor switching noise from a
clear ringing tone to a less noticeable 'white' noise.
This is achieved by slightly and randomly altering the
synchronism of the pulse width modulated output
phases.
14-06 Dead Time Compensation
Option: Function:
[0] Off No compensation.
[1] On Activates dead time compensation.
*
3 3
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