DTC: A motor control technique for all seasons
Electricity+Control, September 2013 (page 27)
(Abridged version as cover story)
Enquiries: Riaan van Jaarsveld, ABB South Africa
Tel. 010 202 5971
Fax: 011 579 8437
The full article on DTC: A motor control technique for all seasons can be downloaded in PDF format.
High-performance ac drives from ABB offer an innovative technology called direct torque control (DTC). As the name suggests, the method controls motor flux and torque directly, instead of trying to control motor currents indirectly like ac vector drives and dc drives. This means better accuracy in matching the driven system’s load requirements. Originated by one of the founding companies of ABB and patented in the mid-1980s, DTC eliminates the need for an extra modulator stage thus achieving control dynamics close to the theoretical maximum.
When ABB introduced its first direct torque control ac drive to the market in 1995, DTC was already a leading technology. Subsequent improvements in processor computational power, application programming, and communication interfaces have continually enabled higher DTC performance, providing premium motor control for a broad range of applications.
- Besides superior torque response, DTC offers many other benefits.
- DTC control is available for different types of motors, including permanent magnet and the new synchronous reluctance motors.
- There is no need for motor speed or position feedback in 95% of applications making costly encoders or other feedback devices unnecessary.