4.1.1 Voltage supply
P 307[0] - CON_VoltageSupply is used to configure the power supply. For single-
axis applications only the settings (0) to (5) are allowed. All other settings should be
used for multi-axis systems. Not all switching frequencies can be used on higher-
powered devices. An excessively high switching frequency setting in conjunction
with high powers may result in a power reduction.
4.1.2 Switching frequency
The switching frequency is set via P 302[0] - CON_SwitchFreq. It is advisable to
initially operate the servo drive with the factory setting (8 kHz). Increasing the
switching frequency can be useful to improve the control dynamism. However, it may
under some circumstances result in a temperature-related loss of power. Switching
frequency noises will decrease with increasing switching frequency (audible range <
12 kHz). For an overview of the currents dependent on the switching frequency refer
to the Operation Manual (see Section "Applicable documentation" on page 12).
4.1.3 Online derating of switching frequency
When P 752[0] - MON_PWM_SwitchFreqSelect_Sel = “AUTO(1)", the switching
frequency is switched in dependence on the current load conditions. If there is a
high load, the operating switching frequency from parameter P 302 - CON_
SwitchFreq is reduced stepwise and when the load is lower, it is subsequently
raised once again via the same steps. Within this context, the system automatically
switches to the next lower or higher possible switching frequency. The individual
switching frequencies between which automatic switching to a lower or back to a
higher frequency is possible depends on the device (!) and on the currently selected
operating switching frequency from parameter P 302 - CON_SwitchFreq. The
switching frequency can be reduced by a maximum of 2 “steps”.
In other words, there are the following 3 levels for the switching frequency:
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
26
4 Power stage
Step0: No reduction of the switching frequency (the operating switching frequency
from P 302 is used).
Step1: 1st reduction step for the switching frequency
Step2: 2nd reduction step for the switching frequency
Via the setting P 752[0] - MON_PWM_SwitchFreqSelect_Sel= "MAN(2)" the
switching frequency can be reduced "externally" online by one or two levels using
the parameter P 758 - CON_SwitchFreq_selMan (value 0: no reduction). This
reduction is "manual" and is directly controlled online; in this case, the controller
does not automatically reduce the value.
4.1.4 Parameters
ID
Index Name / Setting
Unit Description
302
0
CON_SwitchFreq
Power stage switching frequency
2 kHz - 16 kHz (2 kHz only
for BG7)
It is advisable to operate the servo drive with the
default setting. Increasing the switching
frequency can be useful to improve the control
dynamism. Temperature-related derating may
occur. Switching frequency noise decreases as
the switching frequency rises (audible range < 12
kHz).
309
0
CON_EnableWiretest
Enable wire test
409
0
CON_ACT_VDC_TF
ms
Filter time constant for DC link voltage
752
0
MON_PWM_
SwitchFreqSelect_Sel
Switching frequency mode selector
OFF (0)
No function
AUTO (1)
Automatic switchover
MAN(2)
Manual switchover limited by P 758[0]
758
0
CON_SwitchFreq_selMan
Manually configurable power stage switching
frequency
(0)2 kHz
2 kHz
(1)4 kHz
4 kHz
759
0
CON_
UnderVoltageThreshold
V
Overwrite default under voltage threshold level
Table 4.1: “Power stage” parameters
