Description
What kind of stability will a DTC drive have at light loads and low speeds?
The stability down to zero speed is good and both torque and
speed accuracy can be maintained at very low speeds and light
loads. We have defined the accuracies as follows:
Torque accuracy: Within a speed range of 2 to 100 percent
and a load range of 10 to100 percent, the torque accuracy is
2 percent.
Speed accuracy: Within a speed range of 2 to 100 percent and
a load range of 10 to 100 percent, the speed accuracy is 10
percent of the motor slip. Motor slip of a 37 kW motor is about
2 percent which means a speed accuracy of 0.2 percent.
What are the limitations of DTC?
If several motors are connected in parallel in a DTC-controlled inverter, the arrangement operates as one large motor. It has no
information about the status of any single motor. If the number
of motors varies or the motor power remains below 1/8 of the
rated power, it would be best to select the scalar control macro.
Can DTC work with any type of induction motor?
Yes, any type of asynchronous, squirrel cage motor.