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 filter5
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 and motor-side converters have their own control programs. The
parameters of both programs can be viewed and changed using a control panel.
￭
Active braking function (option +N8056 )
The line-side converter with active braking function can transfer regenerated
energy (up to 50% of the rated power) back to the electrical power system. The
active braking function is available with option code +N8056 and licensing.
Example applications:
• tunnel ventilation can achieve quick reversing without brake chopper
• catching up a spinning load and reversing in flying start.
￭
DC voltage boost function
The drive can boost its DC link voltage. In other words, it can increase the operating
voltage of the DC link from its default value.
32 Operation principle
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