CHAPTER 3 – CONTROL SYSTEM 47
Direct torque control
The speed and torque of the motor is controlled by
DTC (Direct Torque Control). DTC provides accu-
rate speed and torque control, and high dynamic
speed response.
Switching of the semiconductors in the INU is
directly controlled in accordance with the motor
core variables flux and torque.
The measured motor currents and DC link voltages
are inputs to an adaptive motor model. The model
produces exact values of torque and flux every 25
microseconds. Motor torque and flux comparators
compare the actual values to reference values
which are produced by the torque and flux refer-
ence controllers.
Depending on the outputs from the hysteresis con-
trollers, the switching logic directly determines the
optimum switch positions every 50 microseconds
and initiates switching whenever required.
Peripheral I/O devices
The peripheral input and output devices connected
to the AMC circuit board of the INU include:
•Local CDP control panel
• IOEC I/O modules for parallel signal transfer to
external devices
•Optional Fieldbus communication interfaces
(option) for serial data transfer to a higher-level
control system
• PC-based service tools comprising:
-DriveWare
®
software tools
DriveWare
®
includes software tools such as
the commissioning and maintenance tools
DriveWindow and DriveDebug, and
DriveOPC for data transfer between ABB
drives and Windows
®
-based applications.
-DriveMonitor
(option)
DriveMonitor is a monitoring and diagnos-
tics tool that allows access to the drive from
any location in the world via a secure inter-
net connection.
3-4 Direct torque control
Speed
controller
Torque-
reference
controller
Torque
flux
comparator
Motor
model
Switching
logic
Switch
positions
Voltage
Current
M
Torque reference
Speed reference
Actual speed
or
To Next Page
Loading...
