Danaher Motion SuperDrive ACS24 Series, User Manual

Page: 59 / 99

26.04.2005
Configuration & control of the AC SuperDrive
6.9.2 T
UNING OF THE SLIP AND STATOR FREQUENCY
ESTIMATION
The Number of Motor Poles is given by the motor manufacturer’s nameplate data and
specifications. Usually equal to 4 or 6.
6.10 C
URRENT CONTROL
6.10.1 B
ASICS
A simplified scheme of the current control is shown in Figure 28 . The dq-plane implemented
current controller (so called vector control) controls the magnetization current and the torque
producing current independently of each other.
Figure 28. Simplified scheme of the Current Control.
The Magnetization Current (reference) is the output from the Flux Controller and the Torque
Current (reference) is the output from the Speed Control. The Magnetization Current is checked
against the constant Max Acs Magnetization Current in order to avoid damage of the drive if a too
high magnetization current is set via the CANopen object dictionary.
From the measured current in phase U and V, the current in phase W is computed based on that
the sum of the phase currents is zero. The measured current is then transformed to the
αβ
-plane
and thereafter follows a transformation to the rotating dq-plane. The Transformation Angle equals
the integral of the stator frequency (i.e. stator angular frequency) and it is equal to the position of
the rotor flux, i.e. the control is rotor flux oriented. The stator frequency is computed as the sum
of the rotor frequency and the slip frequency in the Slip and Stator Frequency Estimation block
(see
Figure 27 ).
The measured currents in the dq-plane, Id (measured magnetization current) and Iq (measured
torque current), are then fed to the Current PI Controller with Decoupling together with the
reference currents and the stator frequency. The reference voltages, Ud Reference and Uq
User's Guide 1.0 Item No.
89Y05120A
59