What is Maximum power: Definition and 83 Discussions
Maximum power point tracking (MPPT) or sometimes just power point tracking (PPT), is a technique used commonly with wind turbines and photovoltaic (PV) solar systems to maximize power extraction under all conditions.
Although it primarily applies to solar power, the principle applies generally to sources with variable power: for example, optical power transmission and thermophotovoltaics.
PV solar systems exist in many different configurations with regard to their relationship to inverter systems, external grids, battery banks, or other electrical loads. Regardless of the ultimate destination of the solar power, the central problem addressed by MPPT is that the efficiency of power transfer from the solar cell depends on the amount of sunlight falling on the solar panels, the temperature of the solar panel and the electrical characteristics of the load. As these conditions vary, the load characteristic that gives the highest power transfer efficiency changes. The efficiency of the system is optimized when the load characteristic changes to keep the power transfer at highest efficiency. This load characteristic is called the maximum power point (MPP). MPPT is the process of finding this point and keeping the load characteristic there. Electrical circuits can be designed to present arbitrary loads to the photovoltaic cells and then convert the voltage, current, or frequency to suit other devices or systems, and MPPT solves the problem of choosing the best load to be presented to the cells in order to get the most usable power out.
Solar cells have a complex relationship between temperature and total resistance that produces a non-linear output efficiency which can be analyzed based on the I-V curve. It is the purpose of the MPPT system to sample the output of the PV cells and apply the proper resistance (load) to obtain maximum power for any given environmental conditions. MPPT devices are typically integrated into an electric power converter system that provides voltage or current conversion, filtering, and regulation for driving various loads, including power grids, batteries, or motors.
Solar inverters convert the DC power to AC power and may incorporate MPPT: such inverters sample the output power (I-V curve) from the solar modules and apply the proper resistance (load) so as to obtain maximum power.
The power at the MPP (Pmpp) is the product of the MPP voltage (Vmpp) and MPP current (Impp).
Hi all,
Checking my answers here as it doesn't seem to match with the answers given to me. Would appreciate if anyone could point out the mistakes I made.
First I will compute Rth. Offing all independent sources, applying a known voltage across R (in this case 1v) and using mesh analysis...
Summary:: Hi I’m in second year mechanical engineering and I really need help with this question! Sorry about my handwriting in the attachment I’ve put in, I've written the question out but there is an image of figure one on the file attached. Many thanks!
[Mentor Note -- Thread moved from a...
Hi,
after calculations I end up in the circuit below¨ (Thevenin equivalent)
So now I have to say Rth=RL and I will find Rx ?The initial circuit is this:
Thanks
Hi all,
I am currently working on a project where the output/load consists of both a variable inductance and variable resistance, whilst the circuit driving this load is a class E radio frequency (RF) power amplifier with low resistance but relatively high/medium reactance (attempting to design...
Homework Statement
Maximum power is transferred to variable load when:
1) RL = Rs
2) RL not equal to 0. and Rs = 0
3) RL = 0 and Rs not equal to 0
4) RL = Rs/2
Homework Equations
Maximum power theorem RL = Rs
The Attempt at a Solution
But if Rs = 0, then current is maximum, so load get...
Homework Statement
In an AC circuit of periodic current we know: ##E=6[V]##, ##R_g=50[Ω]##, ##L_g=\sqrt3 [nH]## and ##ω=50*10^9[s^{-1}]##. Calculate:
a) All available power of the ##E##
b) The resistance of ##R## so that the average power is max
c) That average power from part b)
Homework...
Hello!
Recently I was going through some old exams and upon encountering this problem (which seemed pretty easy) I got stuck. Exams at my university are composed of individual tasks, each having three subquestions with four plausible answers respectively. Solution sheet gives results only, so...
Homework Statement
Given the following circuit find the value of ZL for maximum average power transfer and find the maximum power.
Homework Equations
n = N2/N1
V2/V1 = N2/N1
I2/I1= N1/N2
The Attempt at a Solution
move ZL from the secondary coil to the primary coil using Zs* = ZL/n^2
ZL =...
Homework Statement
Using the maximum power transfer theorem, find the value of R which will result in the maximum power being delivered to R.
Homework Equations
P_max= (V_oc)^2/4(R_th))
R_L=R_th
P_RL=(V_th/(R_th+R_L))^2*R_L
The Attempt at a Solution
I have no clue where to even begin with...
Hello there !
I got question regarding PV cell.
The current at maximum power Im calculated from current-voltage characteristic doesn't equal to the one calculated from P(Ushunt, as you can see in the attached picture. http://prnt.sc/b864hx
Furthermore, the Im from P(U) characteristic is about...
Homework Statement
Given symmetric three phase system (see attachment) of phase voltages with angular frequency \omega=100 rad/s, R=5\omega L=100\Omega. Find capacitance of capacitor C such that power factor of three phase receiver has maximum value.
Homework Equations
Power factor is given by...
Homework Statement
Find the maximal power on resistor R.
Homework Equations [/B]
The Attempt at a Solution
I used Thevenin theorem. I found that Z_t=5+j10 , and U_t= 10-j10. The maximum power happens in this case when $$R=|Z_t| = 5 \sqrt{5}$$ , and I get that P=6.18, while the answer is...
Homework Statement
A 5V battery rated at 1800mAh has a soucre resistance of 10 Ohms. What is the maximum power that can be extracted from the battery?
Homework EquationsThe Attempt at a Solution
I understand that had the battery not had any source resistance then the power out would have been...
Homework Statement
Hey guys,
I have been struggling on this problem for a while now and was hoping I could get a little help
What is wanted is the maximum value of Ro for maximum power.
Homework EquationsThe Attempt at a Solution
Knowing that the Maximum power transfer to Ro would be when...
Homework Statement
The question is showed as below.
Homework Equations
I don't know how to find i when the resistor is 4 ohm.
I think it is quite difficult as the voltage is varying all the time.
So how do I find the current?
Thanks!
The Attempt at a Solution
Hello everyone, I have two generators, piezoelectric and electromagnetic generator. Piezoelectrics are producing maximum voltage across 3 Mohm resistor where as EM generator is producing maximum voltage at 68 ohm. What would be the ideal load for to get the maximum output from both when...
Homework Statement
Homework Equations
V(oc) = I(sc) * R(th)
Kirchoff's voltage law
The Attempt at a Solution
a) is okay. For part b):
After redrawing with the R(th) and V(th) found in part a):
Equations of loops:
s is I(sc)
a is I(left loop)
left loop:
-8 + a(4000) + (a-s)(4000) = 0
right...
Homework Statement
Part (a) has already been solved and determined to be 5kΩ, which has been confirmed by the answer key.
The answer key also states that the maximum power able to be delivered to Ro is 957 µW, but doesn't give any workings or explanations on how to reach this answer...
Homework Statement
Homework Equations
Pmax = ((VTh)2)/(4RTh)
Rparallel = (R1R2)/(R1 + R2)
KCL ΣI = 0
KVL ΣV = 0
The Attempt at a Solution
Okay, so to find RTh, I remove all independent sources and set the "terminals" at R to have a 1A current running through them. Since there is a 30kΩ...
Homework Statement
The variable resistor R in the ciruit is adjusted for maximum power to Ro. what percentage of total power developed in circuit is transferred to R.
Homework Equations
i=V/R
The Attempt at a Solution
So my goal is to put a "fake" charge across v/2(the dependent source) of 1A...
Hi guys, I've been given a question where it asks me to work out : work done , the tension in lifting cable and the maximum power developed and the problem is that I don't know what the maximum power developed means. Isn't it the same as the work done ? If its not, then what's the formula to...
Homework Statement
Find the value of R where RL equals 50 Ω, for maximum power transfer
I= 2A, R_L=50 ohms
Homework Equations
R_th=V_oc/I_sc
KCL,KVL,V=IR
The Attempt at a Solution
First, I created an open circuit including everything except R_L. Then i tried to solve for the Open Circuit...
1. Homework Statement
A voltage source of 240 v having an internal impedance of (3-j4) ohm, is supplying power to a complex load impedance Z1. What will be the maximum power transferred to load?
2. Homework Equations
3. The Attempt at a Solution
Homework Statement
Find the Thévenin equivalent of the circuit and the required value of the load for maximum power transfer for Z = 15 + j24 Ω .
Homework Equations
Voltage divider equation and Z_{in} = Z_{load} 'complex conjugate' for maximum power transfer.
The Attempt at a...
have two solar cells which I have connected in Parallel to increase the current provided to the system. I want to calculate the maximum Power point tracking for my solar cells. There was no information provided by the seller except the one below.
I have attached the open circuit reading of...
Homework Statement
For the following circuit, find the values of RL and CL that maximize the power extracted from the generator.
https://dl.dropboxusercontent.com/u/15390227/circuit.jpg
Homework Equations
Z = R + jX
XL = jωL
XC = 1/jωC
The Attempt at a Solution
Immediately...
Homework Statement
a. Find the Thevenin equivalent circuit across RL.
b. What is the value of RL for maximum power?
c. Calculate the maximum power that can be transferred to the resistor RL.
Homework Equations
The Attempt at a Solution
a. Rth=2.88 ohm
b. RL=2.88 ohm
c...
Homework Statement
a) What value of the load resistor RL will extract the maximum amount of power from the circuit below?
b) How much power will that be?
Hint: you need to use both the concepts of Thevenin equivalent circuits and maximum power transfer.
Homework Equations
The...
Hello,
I was wondering, why is it that when calculating the maximum power transfer, the source voltage is the thévenin voltage, and not the actual source?
What we call the load is arbitrary, no?
Homework Statement
What is the difference between maximum power in load and maximum power by load and circuit?
The Attempt at a Solution
I know max power in load is when Rth (Thevenin) = RL(load). And the equation to find power in load is (Vth^2)/(4*Rth). Not sure how to find max...
Homework Statement
Determine, for the network shown in fig 4 the value of the load
Impedance that will dissipate the maximum power and the value of
this power.Homework Equations
Using Thevenin theorem to simplify the circuit then,I believe maximum power transfer theorems apply.
P=I2R...
Homework Statement
Find the required value of the load to achieve maximum power transfer for Z = 12+24 ohms
Homework Equations
ZL = Zs
[b]3. The Attempt at a Solution [/b
As the question does not state whether or not the phase or magnitude of the load can or cannot be varied. I...
Homework Statement
The daily load demand of a grid is given by P=Pmax * cos(pi*t/24). Here -12hrs ≤ t ≤ 12hrs. Maximum power occurs at (t=0) and minimum occurs at (t= ±12). A 10 GW hydro power plant with pump storage is available for base load operation. The turn-around efficiency of the...
Homework Statement a) For the circuit shown, determine the impedance ZL that results in maximum average power transfer to the ZL
b) What is the maximum average power transferred to the load impedance?Homework EquationsThevenin, Norton procedures, voltage division, current division, etc etcMax...
Homework Statement
For the attached emitter follower circuit, calculate the maximum ac power (Sinusoidal signal) delivered to an attached load.
I have already calculated Rout of the circuit as 19.2Ω, and the voltage at the emitter at operating point (no input signal) as 10.7V (I know...
Hi Folks
I need a bit of help, My weakness is kirchhoffs law and algebra, I know but I still give it a try. For this task I am required to calculate the value of the load (RL) using kirchhoffs and then I have to find the maximum power transfer for the circuit. I have attempted to calculate the...
Homework Statement
http://img855.imageshack.us/img855/6951/captureaww.png
Homework Equations
The Attempt at a Solution
Is one allowed to find R_{Th} by simply short circuiting all voltage source and opening all current sources and finding the equivalent resistance while keeping...
Homework Statement
The current-voltage characteristic of a photovoltaic energy converter (solar cell) shown in the attached figure can be approximated by:
i = I_1(e^{v/V_{TH}} - 1) - I_2
where the first term characterizes the diode in the dark and I2 is a term that depends on light...
Hi,
I'm investigating maximum power transfer in a AC circuit. I understand that for maximum power transfer the reactance both cancel each other out and the value of the source resistance and load resistance have to be equal. I have also found some formulas to prove this.
what i would like...
Hello everyone! I have a general question about how to find out the maximum power transfer to a load resistor with a negative Thevenin Resistance (Rth < 0). I know for positive cases, P = R*(Vth/(R + Rth))^2, in which R is the load resistor connected to the Thevenin equivalence circuit, and Pmax...
Homework Statement
"If the load voltage at the output of a circuit keeps going up as the load resistance is increased, why doesn’t the load power keep going up as well?"
Homework Equations
The maximum power transfer theorem states:
A load will receive maximum power from a network...
Hi everybody,
Below is a circuit that I am investigating. All the components are linear, nothing fancy here.
My goal is to maximize the average power P dissipated in the resistor Re. To this aim, I am only allowed to play with the angular frequency ω of the voltage source and with the value...
Hello.
I need to design a matching circuit to provide maximum power transfer from a generator with impedance Zg to a load with impedance ZL. The matching circuit has a length of transmission line with impedance Z0 and short circuit or open circuit stub with impedance Zs. I need to design with...