What technique is used to control the speed of rotation of a DC motor?

What technique is used to control the speed of rotation of a DC motor?

Linear control works by placing a variable resistor in series with the motor, and adjusting the resistance to vary the voltage across the motor.

How does a cascade control loop work?

Cascade control involves the use of two controllers with the output of the first controller providing the set point for the second controller, the feedback loop for one controller nestling inside the other (Figure 13.19). Such a system can give a improved response to disturbances.

What is the function of inner current loop in a speed controlled DC motor drive?

The Closed Loop Speed Control of DC Motor schemes are provided with inner current control loop in order to limit the current within a safe limit and also to accelerate and decelerate the drive at the maximum permissible current and torque during transient operations.

Which loop should be faster in cascade control system?

In a double loop cascade system, the action of the secondary loop on the process should be faster than that of the primary loop. This ensures that the changes made by the primary output will be reflected quickly in the process and observed when the primary control variable is next measured.

Where is Cascade Control used?

When Should Cascade Control be Used? Cascade control should always be used if you have a process with relatively slow dynamics (like level, temperature, composition, humidity) and a liquid or gas flow, or some other relatively-fast process, has to be manipulated to control the slow process.

What is cascade control used for?

The goal of Cascade Control is to improve process performance by reducing – or even eliminating – the effects of a known disturbance through control of an early warning variable.

What are the functions of inner current control and outer speed control loop?

We can see from the diagram that there are two control loops, which can be said as an inner loop and outer loop. The inner current control loop limits the converter and motor current or motor torque below the safe limit. Now we can understand the function of the control loop and drive by practical examples.

What are various functions of inner current control loop?

The inner control loop controls the motor current and motor torque below a safe limit. Consider a reference speed ω*m which produces a positive error Δ ω*m. The speed error is operated through a speed controller and applied to a current limiter which is overloaded even for a small speed error.

Which control loop needs to be tuned first inner current loop or outer speed control loop?

2. There is a PI tuning block in MATLAB which can help you in that. Typically you tune the inner loop with your specifications and bandwidth. Then the outer loop is chosen to be at least 10 time slower the inner loop, in order to the decouple the two dynamics.

When should cascade control be used?