76
MSD Multi-Axis System Operation Manual DC-AC Servo Drive
Disadvantages
•
The space required due to the Power Supply Unit and its external circuit can, in
some circumstance, be greater than on operation with AC-AC Servo Drive as
the supply or a system comprising AC-AC Servo Drives.
•
The investment costs are higher than for a system comprising AC-AC Servo
Drives or with an AC-AC Servo Drive as the supply.
Power
Supply
Unit
DC-AC
Servo Drive
Motor
DC-AC
Servo Drive
Braking
resitance
AC mains supply
with regeneration
central DC link
Motor
DC-AC
Servo Drive
Motor
Figure 9.1 Block diagram of a multi-axis system with Power Supply Unit and regeneration
9.3 Operation with a Power Supply Unit
In this system variant the DC-supplied DC-AC Servo Drives are connected to a central
Power Supply Unit.
Advantages
•
Regenerative power from one axis is available to the other axes via the central
DC link
•
Surplus energy in the DC link is fed back to the supply system centrally via the
Power Supply Unit
•
Sinusoidal mains current with very low harmonics during motor and regenerative
operation
•
The power factor can be contr
olled at cos
ϕ
= 1 (r
eactive power compensation)
•
Same power ratings for motor operation and regenerative operation
•
The system can have more axes than on supply using one AC-AC Servo Drive
•
Depending on the planning for the Power Supply Unit, all axes can be operated
simultaneously at rated power
•
The installation of the supply cables between the Power Supply Unit and the
DC-AC Servo Drives is convenient and space saving via a continuous busbar
system (Size 1 to 5)
•
The operating costs are lower than for a system comprising AC-AC Servo
Drives or with an AC-AC Servo Drive as the supply
•
Higher DC link voltage than on corresponding AC supply, as a consequence it is
possible to use smaller motors
•
Regulated DC link voltage, therefore it is no longer necessary to take in account
mains voltage fluctuations as a eserve in the system
•
Due to higher DC link voltage, poor supply networks can be compensated and
maximum motor torques achieved in the field-weakening rang
•
Complete compensation of mains voltage dips due to the ability to increase the
voltage
•
High dynamic performance due to fast changes in the energy flow on the load
side
•
If there is a power failure, it is possible to brake via integrated brake choppers
moog
Id. no.: CA97554-001 0
5
/2017
9 Planning
