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).

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  1. PhysicsTest

    Maximizing Power Transfer: An Analysis of Resistance and Efficiency

    I equated dP/dR to 0 and find the solution for R. Is the solution correct?
  2. jisbon

    Engineering Computing the Maximum Power delivered to a Resistor

    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...
  3. jisbon

    Engineering Finding the maximum power delivered using Thevenin's theorem

    Using mesh analysis, my simultaneous equations seem to be wrong and I can't figure out why. Any stuff that I should take note of? Attempt:
  4. N

    Mechanical engineering: Maximum Power Transmitted by a V-Belt Assembly

    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...
  5. M

    Engineering Homework: Rx=? to get maximum power transfer at point M

    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
  6. Adrian Tudini

    Computer models that predict the maximum power of a chemical reaction

    Given a balanced chemical equation, can we predict using computer models the maximum power of the chemical reaction? Thanks.
  7. Physics lover

    Maximum power in this resistor circuit

    My attempt-: So the resistance is coming to be negative.Can anyone tell me my mistake.Thanks.
  8. Mzzed

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  9. J

    Maximum power is transferred when load R = Source R ?

    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...
  10. D

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  11. peroAlex

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  12. O

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  13. A

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  14. I

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  15. G

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  16. C

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  17. JordanHood

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  18. M

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  19. H

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  20. Q

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    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...
  21. I

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    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...
  22. J

    Finding Maximum Power Delivered to Resistor

    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...
  23. G

    Find Maximum Power to Resistor R

    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...
  24. O

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  25. M

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  26. M

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  27. A

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  28. B

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  29. N

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  30. A

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  31. A

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    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...
  32. gfd43tg

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  33. gfd43tg

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    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?
  34. T

    Engineering Understanding Maximum Power in Circuit: Comparing Load and Circuit Approaches

    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...
  35. T

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  36. S

    Network Maximum Power Transfer Calculation

    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...
  37. A

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    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...
  38. F

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    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...
  39. C

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  40. E

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    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...
  41. A

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    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...
  42. G

    Engineering Electrical Circuit Question - Maximum Power Dispated in Resistor

    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...
  43. P

    Maximum power delivered by a solar cell to a resistive load

    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...
  44. D

    I'm investigating maximum power transfer in a AC circuit

    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...
  45. G

    Maximum Power Transfer with Negative Thevenin Resistance?

    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...
  46. JJBladester

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    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...
  47. B

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    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...
  48. M

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    how we make circuit on bread board for maximum power theorem in lab help by image
  49. O

    Engineering Designing a matching circuit for maximum power transfer

    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...
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