Find the real power consumed using MATLAB Simulink

• Fatima Hasan
In summary, the conversation discusses a problem related to calculating real power in an electric circuit. The participants are confused about the given equations and are discussing the definition of real power. They also mention using RMS values to calculate the real power. Ultimately, the solution is to multiply the RMS values of voltage and current to find the true power.
Fatima Hasan
Homework Statement
The question is attached below.
Relevant Equations
Output a sine wave:

O(t) = Amp*Sin(Freq*t+Phase) + Bias
T = 1/Freq
My work is attached below. I want to confirm my answer.
Any help would be greatly appreciated !

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Problem statement

Nor a relevant equation for the 'real power'

Is there a miscommunication here ?

BvU said:
Nor a relevant equation for the 'real power'

Is there a miscommunication here ?

##v(t)=10√2 sin (20πt)##
##i(t)=\frac{5}{√2} sin(20πt)##
The DC and ac values that I got are :
P(dc)=25 W
P(ac)=30.62 W

I reattached the problem statement and my answer below.

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Last edited:
There reeally is no need to attach them for the fourth time. I've seen all three in the first post already. The exercise is quite clear: you are supposed to
Calculate the real power consumed by an electric component where voltage and current are \begin {align*} v(t) & = 10\sqrt 2 \sin (20\pi t) \\ \mathstrut \\ i(t) & = {5\over \sqrt 2} \sin (20\pi t) \end{align*}
So, based on the first picture alone, I should think you need to find a definition of 'real power' and work out what it means in terms of the given ##v## and ##i## ...

I'm not familiar with your software package but I can guess what some of the blocks are supposed to do. (but about the function of the part in the middle

I have no idea).
##\ ##

BvU said:
the function of the part in the middle
It's a transport delay which is equal to T (time=0.1 s).

Nothing to do with the question in this exercise, then !

Fatima,

This is confusing us.

"Find the real power consumed "

only needs algebra to derive the equation.

Output a sine wave:

O(t) = Amp*Sin(Freq*t+Phase) + Bias
T = 1/Freq

That has nothing to do with finding the real power.

Instantaneous power P(t)=V(t)*I(t) has no real and imaginary parts. Real and Imaginary powers apply only to the average over a complete cycle. Calculate the RMS (root mean square) over a cycle.

There's no capacitor in the original problem statement, so why are you even talking about a capacitor? It seems to me that you're just throwing random things together to come up with an answer and hoping it's right. In the process, you're making this problem way too complicated.

I think you should heed @BvU's advice and look up the definition of real power. I'm not sure why you seem so reluctant to do so. It seems silly to start doing calculations if you don't know what you're trying to calculate.

vela said:
There's no capacitor in the original problem statement, so why are you even talking about a capacitor?
Sorry ,I got confused . That was my solution for another question , I will delete it.

vela said:
look up the definition of real power.
Real power is produced when the current and the voltage are in phase with each other .
P in ac circuit = current(rms) * voltage (rms) * cos θ
P = current (rms) * voltage (rms) , (θ=0)
So, I have to find the rms values for current and voltage separately and multiply them together , right ?

You are given the expressions for ##v(t)## and ##i(t)##. What do they tell you about your ##\theta## ?
##\theta = 0## as I think you indicate.
That means that (according to e.g. https://www.allaboutcircuits.com/textbook/alternating-current/chpt-11/true-reactive-and-apparent-power/ ) true power
##P## is ##I^2R = V^2/R = V\,I ##.

With sine square averaging to 1/2 your Prms is indeed Vrms * Irms

FAQ: Find the real power consumed using MATLAB Simulink

MATLAB Simulink is a graphical programming environment used for modeling, simulating, and analyzing dynamic systems. It allows users to create block diagrams that represent a system's components and simulate their behavior over time.

How can I use MATLAB Simulink to find the real power consumed?

To find the real power consumed using MATLAB Simulink, you can use the Powergui block, which is a built-in block in the Simulink library. This block allows you to specify the voltage and current signals of your system and calculates the real power consumed.

What is the difference between real power and apparent power?

Real power is the actual power consumed by a system, while apparent power is the total power that a system appears to be using. Apparent power includes both real power and reactive power, which is the power used to create and maintain magnetic fields in a system.

Can I use MATLAB Simulink for power analysis in both AC and DC systems?

Yes, MATLAB Simulink can be used for power analysis in both AC and DC systems. However, the Powergui block is specifically designed for AC systems. For DC systems, you can use the Powergui block with some modifications, or you can use other blocks such as the Product block to calculate power.

Are there any limitations to using MATLAB Simulink for power analysis?

One limitation of using MATLAB Simulink for power analysis is that it assumes ideal components and does not take into account non-linearities or losses in a system. Therefore, the results may not be entirely accurate in real-world scenarios. Additionally, the Powergui block is limited to single-phase systems and cannot be used for three-phase systems.

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