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ACS6000
USER MANUAL
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03 POWER ELECTRONICS AND CABINET FEATURES
3.2.5.5
Speed and torque control
The speed and torque of the motor is controlled by DTC (direct torque
control). The DTC motor control platform is unique to ABB and has been
proven in all variable speed drives of the ACS product range. DTC provides
accurate speed and torque control, and high dynamic speed response.
DTC is implemented on the AMC circuit board of the INU.
Figure 3-15 DTC control platform
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 voltage 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 produced by the torque and flux
reference controllers.
Depending on the outputs from the hysteresis controllers, the switching
logic directly determines the optimum switch positions every
50 microseconds and initiates switching whenever required.
3.2.5.6
Peripheral I/O devices
The peripheral input and output devices connected to the AMC circuit
board include:
• Local control panels
• S800 I/O system for parallel signal transfer to external devices
(1) Torque reference
(2) Speed reference
(3) Actual speed
(4) Speed controller
(5) Torque reference controller
(6) Torque-flux comparator
(7) Motor model
(8) Switching logic
(9) Switch positions
(10) Voltage
(11) Current
(12) Motor
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