Why use DTC?
Superior torque response is just one feature of DTC.
The technology offers further customer benefits, including:
- No need for motor speed or position feedback in 95% of applications. Thus, installation of costly encoders or other feedback devices can be avoided.
- DTC control is available for different types of motors, including permanent magnet and synchronous reluctance motors.
- Accurate torque and speed control down to low speeds, as well as full startup torque down to zero speed.
- Excellent torque linearity.
- High static and dynamic speed accuracy.
- No preset switching frequency. Optimal transistor switching is determined for every control cycle, allowing the drive to more readily match driven load requirements.
In principle, DTC was already a leading technology back in 1995, but subsequent developments in processor computational power, communication interfaces, application programming, etc., have enabled higher performance, providing premium motor control for a broad range of applications.
DTC’s core is the torque control loop, where a sophisticated adaptive motor model applies advanced mathematical algorithms to predict motor status. Primary controlled variables—stator flux and motor torque—are accurately estimated by the motor model using inputs of motor phase currents and DC bus voltage measurements, plus the states of the power-switching transistors in the drive. The motor model also calculates shaft speed. Temperature compensation helps to enhance calculation accuracy without an encoder.
Download DTC Information.pdf1.7 MB