Direct Torque Control

Direct Torque Control (DTC) is a method used in variable frequency drives to control the torque (and thus the speed) of three-phase AC electric motors. This involves calculating an estimate of the motor’s magnetic flux and torque based on the measured voltage and current of the motor.

Power is nothing without control

Inverter Drive Systems retrofit ABB inverters to motors in a multitude of applications including: pumps, AHUs, refrigeration, fans, hydraulic power packs and manufacturing processes.

Direct Torque Control – In it from the beginning

You can find more detailed information about Direct Torque Control in this Wikipedia article, which provides detailed diagrams and history in which ABB feature:

“The first major successful commercial DTC products, developed by ABB, involved traction applications late in the 1980s for German DE502 and DE10023 diesel-electric locomotives and the 1995 launch of the ACS600 drives family. ACS600 drives has since been replaced by ACS800 drives.”

From Wikipedia  http://en.wikipedia.org/wiki/Direct_torque_control

Although Wikipedia states the first, ABB remains* the only Inverter Manufacturer to produce DTC products.

Superior motor control, here’s the spec:

Motor Control	ABB’s direct torque control (DTC)
Torque control:	Torque step rise time:
Open loop	<5 ms with nominal torque
Closed loop	<5 ms with nominal torque
	Non-linearity:
Open loop	+4% with nominal torque
Closed loop	+3% with nominal torque
Speed control:	Static accuracy:
Open loop	10% of motor slip
Closed loop	0.01% of nominal speed
	Dynamic accuracy:
Open loop	0.3 to 0.4% sec. with 100% torque step
Closed loop	0.1 to 0.2% sec. with 100% torque step

 

*At date of publishing

To discuss direct torque control for your applications please contact one of our engineers on 0115 9441036 or email [email protected]