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).

View More On Wikipedia.org
  1. C

    Number of Resistors needed for a maximum power

    Homework Statement How many resistors, R = 70 ohms can be connected in a series circuit when the maximum power loss of the circuit is 1800W. and the voltages supply is 127V Homework Equations Number of resistors! The Attempt at a Solution P = V2 / x*R x*7=1272/1800 x=1.28 so...
  2. K

    AC Maximum Power Transfer question

    Homework Statement In the circuit attached the load impedance ZL comprises a resistor in parallel with a capacitor. Determine the value of the resistor and the capacitor to ensure that the maximum power is received by the load impedance. The Attempt at a Solution So,if components in ZL...
  3. O

    What factors determine the maximum power of a 4-stroke engine per cylinder?

    Is there any equation for calculating the maximum power possible for a given 4 stroke engine? per cylinder. I guess it would involve: Octain rating of fuel used RPM CC some factor of bore X Stroke And an efficiency of 100%!
  4. T

    Max Power Transfer Homework: Solve for RL & Calculate Pmax

    Homework Statement Determine the value of RL that will draw the maximum power from the rest of the circuit shown below. Calculate the maximum power. (This problem was included in our exam this week, and I don't really recall the exact values of the parameters, but I'm pretty sure that the...
  5. F

    Maximum power transfer vs Max power efficiency

    Hello forum, what is the main difference between max power transfer and max power efficiency? In the case of max power transfer, the goal is to transfer the most energy to the load per unit time (impedance matching). Power is I*V and is about delivering energy very fast... High power...
  6. G

    Maximum Power transfer theorem ( Power dissipation in resistors in circuits)

    the equation P = (E2R) / [(R-r)2 + 4Rr] We say that when R=r , P = E2/4R which is said to be maximum.. But if I say R→∞ , then r→0 and then P = E2/R which is greater.. So, shouldn't power be maximum for max R ?
  7. Twinflower

    Thévenin resistance and Load resistance vs maximum power

    Homework Statement This is the network. The problem states that a new resistor is put between A and B, in parallel with R4. I should find the ideal resistance for this load resistor and show that this is indeed the ideal resistance for maximum power output. Homework Equations...
  8. O

    Maximum power when torque is 0 and angular velocity is 0

    Homework Statement What is the power the drill can supply at the two points of interest(The intersections at the axis') This is a direct translation of the dutch problem. So basically what's going on is we made measurements of the RPM and angular displacement of our mechanical system...
  9. L

    Maximum power theory in electronics

    Homework Statement Please see my attachment. From the circuit Energy transferred to the load E = Ir + IR, where r is the internal resistance and R is Load Resistance. so I = E/(r+R) Homework Equations The Attempt at a Solution The Power W is W = I2R = E2R/(r+R)2 Upto this i...
  10. B

    Maximum power with transformers

    Homework Statement In Figure 1, the transform is perfect (k = 1). Calculate the maximum power which can be transferred to the load ZL. Design a dipole which that power can be transferred to. Homework Equations k = 1 --> n = sqrt(L1/L2). Pmax = |V(rms)|/(4*Rg) The result must be Pmax = 0.368 W...
  11. bcrowell

    Deriving GR from maximum power

    MTW has a cute argument on p. 980 that the maximum power radiated from any system is a fixed number, about 10^53 W. I came across this and filed it away as a piece of cool trivia. But it turns out that apparently you can derive the GR field equations from nothing more than the assumption that...
  12. J

    Maximum power dissipation for resistors

    there are 3 resistors of, different values. 470o,22o and 100o. but each one is 500W I want to connect them in series/parallel in order to dissipate the maximum power 500W. I have connected 4,22o in series and 2, 100o in series, 1, 470 in parallel. but the dissipation is not maximum. the...
  13. S

    What maximum power must the motor provide?

    [b]1. A loaded ore car has a mass of 950 kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable connected to a winch. The shaft is inclined at 30.0° above the horizontal. The car accelerates uniformly to a speed of 2.20 m/s in 12.0 s and...
  14. PainterGuy

    Understanding maximum power transfer theorem

    Hi :) I'm trying to understand 'background' working of the maximum power transfer which says that power transfer takes place across R_L when it is equal to R_th (R_L is load resistance and R_th is Thevenin resistance). It is easily proved by doing some math. P=VI, P=I^2.R, P=V^2/R...
  15. G

    How Does Train A's Maximum Power Influence Its Equation of Motion?

    The maximum power that a train A of mass m can exert when traveling at a velocity v is Pv^{3/2} where P is a constant. The resistance to motion is kv. Why is the equation of motion of A at full power given by: Pv^{1/2}-kv=m\frac{dv}{dt}?
  16. D

    Find L & C for Maximum Power Transfer to Load Resistor

    Homework Statement Find L & C so that maximum power is delivered to load resistor. ___l 50 ohm l___ ( inductor L )____.____ ( inductor L )___ l . . . . . . . . . . . . .. . . . . . . . . . . l . . . . .. . . . . . . . . . l 10 V ac source . . . . . . . . ( Capacitor...
  17. B

    Smith Chart and Maximum Power Transfer

    Homework Statement You can find the problem http://whites.sdsmt.edu/classes/ee382/homework/382Homework9.pdf" . It is problem 9.2. Homework Equations Zin = Zs* (maximum power) The Attempt at a Solution I've already figured out the first part of this problem. I plotted the normalized...
  18. P

    Maximum power transfer theorem

    i was solving one question...it said find out value of r in a circuit so that the 6 ohm resistor consumes maximum power...i applied max power theorem ...and calculated the thevenin eqivalent resistance accrss 6 ohm resistance...and put it equal to 6...but the r cam eout to be negative...so wat...
  19. A

    Maximum Power Dissipation at Internal Resistance Proof

    Homework Statement My physics teacher (i'm in year 12) set me a "challenge" to prove a graph in our textbook, which shows Power against Resistance, with a local maximum where R = internal resistance, r. He told me i'd need to use differentiation, P = I^{2}.R and said that I was right in...
  20. V

    Max Power Output of Solar-Thermal Plant in Desert

    Homework Statement A solar-thermal power plant is to be built in a desert location where the only source of cooling water is a small creek with average flow rate of 100kg/s and an average temperature of 30 degrees C. The plant is to cool itself by boiling away the entire creek. If the...
  21. H

    What is the maximum power of the variable resistor R?

    Homework Statement (a) For the circuit below, the value of R is adjusted so that each of the two 10Ω resistors dissipates 10W. Calculate the value of the variable resistor R. (b) What is the value of R if it is adjusted to dissipate the maximum power possible? For this value of R...
  22. N

    How can I solve for the Thevenin resistance in this circuit?

    I'm doing some practice problems, and I can't seem to figure out where to even begin with this one. I've tried solving for R_{T} (Thevenin resistance) by removing the 9V source and adding a 1V test source across the load, and I've also tried solving for R{_T} by leaving the 9V source in the...
  23. C

    Engineering Max Power Circuit Homework: Find Max Power w/o Load Resistance

    Homework Statement http://img63.imageshack.us/img63/80/circuit1.jpg Homework Equations P = (I^2)(R) The Attempt at a Solution First, I turned the 2A and 4A current sources into voltage sources by V = IR. So (2A)(10Ω) = 20V and (4A)(12Ω) = 50V Then I had the circuit simplified...
  24. R

    Maximum power transfer theorem

    show that the power absorbed by the load is half the power delivered by source when the load and source impedances are conjugates.
  25. P

    Finding the maximum power delivered from a baterry

    Homework Statement A battery of emf [insert symbol for emf here] and internal resistance is hooked up to a variable "load" resistance R. If you want to deliever the maximum possible power to the load, what resistance should you choose?(You can't change the emf and r, of course). Homework...
  26. I

    Can Adding Resistance to a Load Increase Maximum Power?

    I need some help to understand the maximum power theorom. From what I understand it states that in order to get maximum power from a source you have to match the resistance of the source to the resistance of the load. Now what i don't understand is how could adding resistance to a load generate...
  27. Q

    What is the maximum power transfer equation?

    hello!well i have the exercice below(attachement) and i need to find the maximum power transferred to Rl..how can i do this without even knowing the value of Rl? thank you
  28. S

    Is My Calculation of Maximum Power Correct in This Circuit Analysis?

    1. http://img503.imageshack.us/img503/1480/21144697lh1.jpg [/URL] 3. Pmax = Vth^2/4Rth so I am guessing i treat R as the Rth and find Rth. to find Rth i must turn off all independent sources. Since the dependent source exists i added a one voltage source at the Rth terminals and put a...
  29. H

    What is Bob's maximum power output as he throws the rock?

    Homework Statement Bob can throw a 500 g rock with a speed of 30 m/s. He moves his hand forward 1.0 m while doing so. a. How much work does Bob do on the rock? b. How much force, assumed to be constant, does Bob apply to the rock? c. What is Bob's maximum power output as he throws the rock...
  30. T

    Maximum Power Output of a Turbine

    Hi, I need with the following question. Argon gas expands in an adiabatic turbine from 3MPa and 750 C to .2 MPa at a rate of 5 kg/s. Neglect KE and PE effects. Find maximum power output. I know I need to first find the temperature of state two and then use that to solve for h2 (I have...
  31. P

    Why Is Torque at Maximum Power Less Than Maximum Torque?

    Explain why the torque developed at maximum power is less than the maximum torque maximum torque of 165 Nm at 4300 rev/min and its maximum power 88 kW at 5500 rev/min Torque developed at maximum power T = bp x 60 2pN = 88000 x 60 2 x p x 5500 = 152.8 Nm...
  32. D

    What is the maximum power rating of a kettle

    Hey, i got a circuit question, and I'm not sure if i did it right, and was wondering if anyone could show me how to do it A 750W microwave oven is plugged into an outlet and turned on. All three lights are on. What is the maximum power rating of a kettle that could be operated in the other...
  33. A

    Power and maximum power problem

    A loaded ore car has a mass of 950kg and rolls on rails with negligible friction. It starts from rest and is pulled up a mine shaft by a cable connected to a winch. The shaft is inclined at 30 degrees above the horizontal. the car accelerates uniformly to a speed of 2.2m/s in 12 sec and...
Back
Top