Determine the gain of the proportional controller.

In summary, the block diagram shows the control of an electric heating system which is driven by a voltage-controlled power supply. The proposed solution to eliminate the effect of disturbances is to incorporate a transducer that measures the external temperature and feeds a signal back to the input via a proportional controller with a required gain value of 25.
  • #1
rrab186
5
0
The block diagram (attached) shows the control of an electric heating
system. The heater is driven from a voltage-controlled power supply, the
voltage V1 being derived from a potientiometer. The output temperature,
θO, is subject to disturbances, θD, because of changes in the ambient
temperature. It is proposed to apply 'disturbance feedback control' to the
system by the inclusion of a transducer that measures the external
temperature and feeds a signal back to the input via a proportional
controller of gain H.Determine the required value of H to eliminate the effect of the disturbanceDon't really know where to start with this, would be gratefull for any help. Thanks!
 

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  • #2
rrab186, if you get no help with this in the next 24 hrs, could I suggest that you replace the .doc with a .jpg as I don't have the software to view .doc files.
 
  • #3
Here's a jpeg of the diagram.

I have managed to get an answer of 25, not sure if this is correct.
 

Attachments

  • block diagram jpeg.jpg
    block diagram jpeg.jpg
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  • #4
rrab186 said:
Here's a jpeg of the diagram.

I have managed to get an answer of 25, not sure if this is correct.
So you've figured it out? What units would it have if you actually built it?
 
  • #5


I would approach this problem by first understanding the concept of gain in a proportional controller. Gain refers to the ratio of the change in output to the change in input. In this case, the input is the signal from the transducer measuring the external temperature, and the output is the voltage V1 that controls the power supply to the heater.

To determine the required value of H, we need to consider the relationship between the disturbance and the output temperature. The disturbance, θD, affects the output temperature, θO, through the voltage V1. Therefore, we can express the relationship as θO = HV1 + θD.

To eliminate the effect of the disturbance, we want θO to be equal to θD. This means that we need to choose a value of H that makes HV1 equal to θD. We can rearrange the equation to solve for H: H = θD/V1.

Therefore, the required value of H to eliminate the effect of the disturbance is the ratio of the disturbance to the input voltage V1. This value will depend on the specific system and the magnitudes of the disturbance and input voltage. By adjusting H accordingly, we can achieve disturbance feedback control and maintain a stable output temperature despite changes in the ambient temperature.
 

1. What is a proportional controller?

A proportional controller is a type of feedback control system that uses a proportional gain to adjust the output in proportion to the error signal. It is commonly used in industrial and engineering applications to maintain stability and accuracy in systems.

2. How is the gain of a proportional controller determined?

The gain of a proportional controller is determined by analyzing the system's response to different proportional gain values. The gain is increased or decreased until the desired response, such as stability or speed, is achieved.

3. What is the significance of the gain in a proportional controller?

The gain in a proportional controller determines the strength of the control action. A higher gain means a stronger response to changes in the error signal, while a lower gain means a weaker response. The appropriate gain value is crucial in achieving the desired system performance.

4. How does a proportional controller compare to other types of controllers?

A proportional controller is simpler and more straightforward compared to other types of controllers like integral and derivative controllers. It only uses the error signal to adjust the output, while other controllers also consider the system's history and future behavior.

5. What are the advantages of using a proportional controller?

Proportional controllers have a fast response time, are easy to implement, and require minimal tuning. They are also stable and can handle disturbances and changes in the system. Additionally, they are more cost-effective compared to other types of controllers.

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