Operation principle
The ACS880-11 is a four-quadrant drive for controlling asynchronous AC induction
motors, AC induction servomotors, permanent magnet motors and synchronous
reluctance motors.
The drive includes a line-side converter and a motor-side converter. The parameters
and signals for both converters are combined into one primary user program.
The figure below shows the simplified main circuit diagram of the drive.
T1/U
T2/V
T3/W
4
21
3
L1
L2
L3
5
UDC+ UDC-
A
DriveA
LCL filter1
Line-side converter2
DC link. DC circuit between the line-side converter and motor-side converter.3
Motor-side converter4
Common mode filter (option +E208)5
The line-side converter rectifies three phase AC current to direct current for the
intermediate DC link of the drive. The intermediate DC link further supplies the motor-side
converter that runs the motor.
Both converters consist of six insulated gate bipolar transistors (IGBT) with free wheeling
diodes. The content of AC voltage and current harmonics is low. The LCL filter
suppresses the harmonics further.
The line-side converter can transfer energy from the electrical power system to the drive
DC link and vice versa. Thus the drive can operate the motor in all four quadrants (speed,
torque). The figure below visualizes the operation of the four-quadrant drive. In quadrants
I and III, the drive operates in the motoring mode and takes energy from the power
system. In quadrants II and IV, the drive operates in generating mode, and regenerates
energy back to the power system.
28 Operation principle and hardware description
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