What is direct torque control of induction motor?

Direct torque control (DTC) is an emerging technique for controlling PWM inverter-fed induction motor (IM) drives. It allows the precise and quick control of the IM flux and torque without calling for complex control algorithms. In principle, moreover, it requires only the knowledge of the stator resistance.

What is meant by direct torque control?

Direct torque control (DTC) is one method used in variable-frequency drives to control the torque (and thus finally 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.

What is the basic principle of direct torque control method?

Direct Torque Control (DTC) is an optimised AC drives control principle where inverter switching directly controls the motor variables: flux and torque. The measured input values to the DTC control are motor current and voltage. The voltage is defined from the DC-bus voltage and inverter switch positions.

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What is the difference between DTC and FOC?

In summary, DTC provides a better dynamic torque response, whereas the FOC provides a better steady state behaviour. DTC might be preferred for high dynamic applications, but shows higher current and torque ripple. … FOC is very dependent on knowledge of the rotor time constant when using an induction machine.

What is DTC control in drive?

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.

What is meant by torque control?

A control method that enables the torque generated by a motor to be equal to a torque reference input. Torque control is suitable for tension control of a winding machine and other applications.

What is the difference between speed control and torque control?

With pure speed control, you twist the throttle and it feeds more voltage at the maximum current it can do. With pure torque control, you twist the throttle a bit, and it adds more current, turning the motor harder.

What is torque control in VFD?

Torque control mode allows for the VFD to directly control motor torque instead of motor speed. This is necessary for any application where torque takes priority over speed. Winder, rewinders, capping, and web applications are some good examples of when torque control is utilized.

How do you control torque on an AC motor?

The torque control as well as speed control is obtained using induction motors fed from variable frequency inverters. The inverter is controlled such that the motor operates with constant flux, to achieve the best possible torque capability of the motor. Both voltage source and current source inverters can be employed.

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What is rotor speed control in 3 phase induction motor?

Injecting Slip Frequency EMF into Rotor Side

When the speed control of three phase induction motor is done by adding resistance in rotor circuit, some part of power called, the slip power is lost as I2R losses. Therefore the efficiency of three phase induction motor is reduced by this method of speed control.

What are the advantages of vector control?

Vector Control offers the advantages of better speed holding, better response to sudden load changes as well as greatly improved torque at low speeds. Motors often run more efficiently – and therefore cooler.

What is speed control of induction motor?

By Injecting EMF In Rotor Circuit

Speed control of induction motor is done in this method by injecting a particular voltage in the rotor diagram. The injected voltage (emf) needs to have an equal frequency with the slip frequency. However, there is no limitation for the phase of that emf.

What is scalar control of induction motor?

At the scalar control method, the induction motor speed is controlled by setting the voltage and frequency of the stator, so that the magnetic field in the gap is maintained at the desired value. To maintain a constant magnetic field in the gap, the V/Hz ratio must be constant at different speeds.