4.1.1 Voltage supply
P 307[0] - CON_VoltageSupply is used to configure the power supply. For single-
axis applications, only 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
MOOG
ID
No.:
CB40859-001
Date:
02/2018
MSD Servo Drive - Device Help
26
4 Power Stage
The switching frequency is set via P 302[0] - CON_SwitchFreq. It is advisable to
initially operate the drive controller 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 11).
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 steps for reducing the switching frequency:
Step0: No reduction of the switching frequency (the operating switching frequency
from P 302 is used).
Step1 (1) reduction step for the switching frequency
Step2 (2) reduction step for the switching frequency
The setting P 752[0] - MON_PWM_SwitchFreqSelect_Sel = "MAN(2)" works exactly
the same as the setting AUTO(1), except that in this case, the maximum reduction of
the switching frequency is limited via the specification of the maximum step level in
parameter P 758 - CON_SwitchFreq_selMan.
4.1.4 Parameters
ID
Index Name / Setting
Unit Description
302
0
CON_SwitchFreq
2 kHz - 16 kHz (2 kHz only
for BG7)
309
0
409
0
ms
752
0
Power stage switching frequency
It is advisable to operate the drive controller 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).
Enable wire test
Filter time constant for DC link voltage
Switching frequency mode selector
758
0
CON_EnableWiretest
CON_ACT_VDC_TF
MON_PWM_
SwitchFreqSelect_Sel
OFF (0)
AUTO (1)
MAN(2)
CON_SwitchFreq_selMan
Step0 (0)
Step1 (1 )
Step2 (2)
No function
Automatic switchover
Automatic switching, limited via
P 758[0]
Step level for the lower limit of the automatically
reduced switching frequency
Switching frequency not reduced
Switching frequency reduced at most by only one
step
Switching frequency reduced at most by up to
two steps
Table 4.1: “Power stage” parameters
