BECKHOFF DK9222-0610-0027 - Manual (Page 3)

I/O
Motion
Application Note DK9222-0610-0027
Power supply of electrical drives – problems from real applications
A Voltage peaks at the power supply unit
In highly dynamic applications, fast decelerations cause the feedback of energy, which will lead to voltage spikes at the power
supply unit. The overvoltage spikes can destroy the power supply unit. ’Intelligent’ power supplies with overvoltage protection
switch themselves off briefly, but this results in the drive losing control. These are all factors that will significantly impair
system reliability.
V DC
max. t
U
Fig. 2 Voltage spikes at the power supply unit
B Ripple currents
I
t
Fig. 3 Occurrence of ripple currents
Ripple currents occur during fast acceleration. The power supply unit can no longer compensate, resulting in voltage drops.
Ripple currents additionally occur with the commutation of DC machines, which have a negative influence on synchronization,
particularly in the case of short start/stop ramp times of the motors, and appear as torque ripple (rough mechanical operation).
New Automation Technology Beckhoff 3
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