In this thesis, we examine a schematic to extract maximum obtainable solar power from a PV module and use the energy for a DC application. This project investigates in detail the concept of Maximum Power Point Tracking MPPT which significantly increases the efficiency of the solar photovoltaic system. Renewable energy is the energy which comes from natural resources such as sunlight, wind, rain, tides and geothermal heat.
These resources are renewable and can be naturally replenished. Therefore, for all practical purposes, these resources can be considered to be inexhaustible, unlike dwindling conventional fossil fuels [1]. The global energy crunch has provided a renewed impetus to the growth and development of Clean and Renewable Energy sources. Apart from the rapidly decreasing reserves of fossil fuels in the world, another major factor working against fossil fuels is the pollution associated with their combustion.
Contrastingly, renewable energy sources are known to be much cleaner and produce energy without the harmful effects of pollution unlike their conventional counterparts. Wind turbines can be used to harness the energy [3] available in airflows.
Current day turbines range from around kW to 5 MW [4] of rated power. Since the power output is a function of the cube of the wind speed, it increases rapidly with an increase in available wind velocity. Recent advancements have led to aerofoil wind turbines, which are more efficient due to a better aerodynamic structure.
The tapping of solar energy owes its origins to the British astronomer John Herschel [5] who famously used a solar thermal collector box to cook food during an expedition to Africa. Solar energy can be utilized in two major ways. Firstly, the captured heat can be used as solar thermal energy, with applications in space heating. Another alternative is the conversion of incident solar radiation to electrical energy, which is the most usable form of energy. This can be achieved with the help of solar photovoltaic cells [6] or with concentrating solar power plants.
Hydropower installations up to 10MW are considered as small hydropower and counted as renewable energy sources [7]. These involve converting the potential energy of water stored in dams into usable electrical energy through the use of water turbines. Run-of-the-river hydroelectricity aims to utilize the kinetic energy of water without the need of building reservoirs or dams. Plants capture the energy of the sun through the process of photosynthesis.
On combustion, these plants release the trapped energy. This way, biomass. Geothermal energy is the thermal energy which is generated and stored [9] within the layers of the Earth. The gradient thus developed gives rise to a continuous conduction of heat from the core to the surface of the earth. This gradient can be utilized to heat water to produce superheated steam and use it to run steam turbines to generate electricity. The main disadvantage of geothermal energy is that it is usually limited to regions near tectonic plate boundaries, though recent advancements have led to the propagation of this technology [10].
The current trend across developed economies tips the scale in favour of Renewable Energy. For the last three years, the continents of North America and Europe have embraced more renewable power capacity as compared to conventional power capacity. As can be seen from the figure-1, wind and biomass occupy a major share of the current renewable energy consumption. Recent advancements in solar photovoltaic technology and constant incubation of projects in countries like Germany and Spain have brought around tremendous growth in the solar PV market as well, which is projected to surpass other renewable energy sources in the coming years.
By , more than 85 countries had some policy target to achieve a predetermined share of their power capacity through renewables. This was an increase from around 45 countries in Solar cells are the basic components of photovoltaic panels. Most are made from silicon even though other materials are also used. Solar cells take advantage of the photoelectric effect: the ability of some semiconductors to convert electromagnetic radiation directly into electrical current.
The charged particles generated by the incident radiation are separated conveniently to create an electrical current by an appropriate design of the structure of the solar cell, as will be explained in brief below.
A solar cell is basically a p-n junction which is made from two different layers of silicon doped with a small quantity of impurity atoms: in the case of the n- layer, atoms with one more valence electron, called donors, and in the case of the p-layer, with one less valence electron, known as acceptors.
When the two layers are joined together, near the interface the free electrons of the n-layer are diffused in the p-side, leaving behind an area positively charged by the donors. Similarly, the free holes in the p-layer are diffused in the n-side, leaving behind a region negatively charged by the acceptors. This creates an electrical field between the two sides that is a potential barrie to further flow. The equilibrium is reached in the junction when the electrons and holes cannot surpass that potential barrier and consequently they cannot move.
This electric field pulls the electrons and holes in opposite directions so the current can flow in one way only: electrons can move from the p-side to the n-side and the holes in the opposite direction. A diagram of the p-n junction showing the effect of the mentioned electric field is illustrated in Figure 2.
Metallic contacts are added at both sides to collect the electrons and holes so the current can flow. In the case of the n-layer, which is facing the solar. The structure of the solar cell has been described so far and the operating principle is next. The photons of the solar radiation shine on the cell.
Three different cases can happen: some of the photons are reflected from the top surface of the cell and metal fingers. Those that are not reflected penetrate in the substrate. Some of them, usually the ones with less energy, pass through the cell without causing any effect. Only those with energy level above the band gap of the silicon can create an electron-hole pair.
These pairs are generated at both sides of the p-n junction. The minority charges electrons in the p-side, holes in the n-side are diffused to the junction and swept away in opposite directions electrons towards the n-side, holes towards the p-side by the electric field, generating a current in the cell, which is collected by the metal contacts at both sides.
This can be seen in the figure above, Figure 2. This is the light-generated current which depends directly on the irradiation: if it is higher, then it contains more photons with enough energy to create more electron-hole pairs and consequently more current is generated by the solar cell.
The solar cell can be represented by the electrical model shown in Figure 3. Its current voltage characteristic is expressed by the following equation:. Where I and V are the solar cell output current and voltage respectively, I0 is the dark saturation current, q is the charge of an electron, A is the diode quality ideality factor, k is the Boltzmann constant, T is the absolute temperature and RS and RSH are the series and shunt resistances of the solar cell.
RS is the resistance offered by the contacts and the bulk semiconductor material of the solar cell. The origin of the shunt resistance RSH is more difficult to explain. It is related to the non ideal nature of the pn junction and the presence of impurities near the edges of the cell that provide a short-circuit path around the junction [4].
However, this ideal scenario is not possible and manufacturers try to minimize the effect of both resistances to improve their products. Sometimes, to simplify the model, the effect of the shunt resistance is not considered, i. RSH is infinite, so the last term in equation 1 is neglected. Two important points of the current-voltage characteristic must be pointed out: the open circuit voltage VOC and the short circuit current ISC.
At both points the power generate is zero. VOC can be approximated from 1 when the output current of the cell is zero, i. It is represented by equation 2. The maximum power is generated by the solar cell at a point of the current-voltage characteristic where the product VI is maximum. This point is known as the MPP and is unique, as can be seen in Figure 3, where the previous points are represented. It is a widely used measure of the solar cell overall quality. The reason for that is that the MPP voltage and current are always below the open circuit voltage and the short circuit current respectively, because of the series and shunt resistances and the diode depicted in Figure 2.
The typical fill factor for commercial solar cells is usually over 0. Two important factors that have to be taken into account are the irradiation and the temperature. They strongly affect the characteristics of solar modules. As a result, the MPP varies during the day and that is the main reason why the MPP must constantly be tracked and ensure that the maximum available power is obtained from the panel.
I and voltage-power V-P characteristics is depicted in Figure 4, where the curves are shown in per unit,. As was previously mentioned, the photo- generated current is directly proportional to the irradiance level, so an increment in the irradiation leads to a higher photo-generated current. Moreover, the short circuit current is directly proportional to the photo-generated current; therefore it is directly proportional to the irradiance.
When the operating point is not the short circuit, in which no power is generated, the photo-generated current is also the main factor in the PV current, as is expressed by equations 1. For this reason the voltage-current characteristic varies with the irradiation. In contrast, the effect in the open circuit voltage is relatively small, as the dependence of the light generated current is logarithmic, as is shown in equation 4. Figure 5 shows that the change in the current is greater than in the voltage.
In practice, the voltage dependency on the irradiation is often neglected. As the effect on both the current and voltage is positive,. The temperature, on the other hand, affects mostly the voltage. The open circuit voltage is linearly dependent on the temperature, as shown in the following equation:. According to 5 , the effect of the temperature on VOC is negative, because Kv is negative, i.
The current increase with the temperature but very little and it does not compensate the decrease in the voltage caused by a given temperature rise. That is why the power also decreases. PV panel manufacturers provide in their data sheets the temperature coefficients, which are the parameters that specify how the open circuit voltage, the short circuit current and the maximum power vary when the temperature changes.
As the effect of the temperature on the current is really small, it is usually neglected. Figure 6 shows how the voltage-current and the voltage-power characteristics change with temperature. The curves are again in per unit, as in the previous case. As was mentioned before, the temperature and the irradiation depend on the atmospheric conditions, which are not constant during the year ad not even during a single day; they can vary rapidly due to fast changing conditions such as clouds.
This causes the MPP to move constantly, depending on the irradiation and temperature conditions. If the operating point is not close to the MPP, great power. Hence it is essential to track the MPP in any conditions to assure that the maximum available power is obtained from the PV panel.
In a modern solar power converter, this task is entrusted to the MPPT algorithms. The basic schematic of a buck-boost converter. Two different topologies are called buckboost converter. Both of them can produce an output voltage much larger in absolute magnitude than the input voltage. Both of them can produce a wide range of output voltage from that maximum output voltage to almost zero. A buck step-down converter followed by boost step-up converter. The output voltage is of the same polarity as the input, and can be lower or higher than the input.
Such a non-inverting buck-boost converter may use a single inductor that is used as both the buck inductor and the boost inductor. This page describes the inverting topology. The buckboost converter is a type of that has an output voltage magnitude that is either greater than or less than the input voltage magnitude. It is a switched- mode power supply with a similar circuit topology to the boost converter and the buck converter.
The output voltage is adjustable based on the duty cycle of the switching transistor. One possible drawback of this converter is that the switch does not have a terminal at ground; this complicates the driving circuitry. Also, the polarity of the output voltage is opposite the input voltage. Neither drawback is of any consequence if the power supply is isolated from the load circuit if, for example, the supply is a battery as the supply and diode polarity can simply be reversed.
The switch can be on either the ground side or the supply side. While in the On-state, the input voltage source is directly connected to the inductor L. This results in accumulating energy in L. In this stage, the capacitor supplies energy to the output load.
Op amps can control the switching. If you google "the back shed mppt circuit" you will find what I have explained. Bro I need your kind consideration upon that one, please. Its gorgeous and succinct. I know it bro, I thought you'd find it difficult to build the PWM version and therefore I referred a simpler option to you.
For the PWM version you can take a peek at this article, I think this is exactly what you may be looking for:. It is, and I hate to whine to you but it uses a P channel mosfet. Being rare for some reason , P channel power mosfets are expensive over here, like a dollar for one. Then, I am located far away living on a farm in remote Punjab.
I have plenty of n channel mosfets and transistors though and the usual items like 's, 's, s, and a whole lot of scrap including transformers from local made UPS units. The other concern I have is that internet searches bring forth the advanced concepts like H bridge and full bridge mosfets driven by the latest ICs which I do not have.
But the coolest idea of a based PWM driving mosfets and "chopping" the power coming down from the solar panels and tailoring it to my need seems most feasible to me for now. I have made simulations of all the circuits you have developed, all of them, however they don't simulate very well because the applet I'm using, developed by Paul Falstad, does not have a PV input.
Otherwise the circuit you have shown here is quite good being simple. Secondly the PV array is 2 kilo watts of power. And I'm not sure how to add mosfets to share the power. To be honest, Mosfets are sophisticated things with a lot of "nakhra" to take care of in their design, as you know.
I could use a small army of D NPN transistors instead if need be I have plenty of these from scrap , driven by a based PWM and a or two as comparators, sensing and controlling the voltage limits as long as the circuit doesn't let them go linear to waste the power being conducted down. But I am a newbie so I'm not so confident in designing it. Bro you agreed to help me. Perhaps you could take the time to design such a thing for me? Pretty please.
My wife and children are visiting their parents and I want to get the solar power up and running by the time they return which is a week from now. And with all the frequent rains I don't have much outdoor farming work to do anyway. What do you say dear bro? Thanks bro, for the nice explanation, I'll try to design and publish the required circuit, specific to your application. It may take some time though, since it would be quite an elaborate article and might take a lot of thinking….. Okay thank you Swagatam, I'll be looking forward to it.
In the mean time, I think I am going to build the circuit on this page and instead of a transistor I'm going to use a bunch of car relays driven by the I hope the IC will not be switching them too much because I do not want the inductive kickback spikes from fast switching relays to damage the UPS.
Am going to start building this ASAP. I intended to send you report and photos of any build designed by you so I will send you photos of it, hopefully. Sorry bro, you cannot use relays here, because the switching is supposed to be very rapid, either a mosfet or a transistor will only work for the above circuits. Brother forgive me but kindly do me this one favor only, modify the 48 volt circuit on this very page only to handle 2 kilo watts of power.
The more I read about drive requirements for transistors and mosfets the more I feel ignorant about them. You're the guru so please guru ustad take the time to make this small modification. I will acquire the PNP transistors and everything else. This one here, aptly named Poor man's mppt is the best of them all when it comes to simplicity and efficiency. Sure Bro! I am always ready to help!
However the above circuits were built on an mistaken assumption…so it wouldn't be a good idea to try these circuits won't simulate an MPpT, In my previous comment I suggested you an alternative circuit I would recommend you to try that instead of the above.
I would be updating the article soon with a correct version so that the circuits works more like an MPpT. Still waiting for the update.
Bro Majumdar its not so necessary to make it mppt. It just needs to be efficient. Its meant for poor people any way. A full bridge buck converter that can handle the amps and its limits governed by a few ICs may as well do the trick. Another quick question please. In the schematic for the 48v version, isn't the 78L12 receiving excessive voltage from the 60V solar panel? I have watts solar panel and i want to build mppt solar charge controller, please send me circuit diagram and component list.
Sir Swagatam Majumdar. Sir we are working on Perturb and observe method. Can u provide me with a working dc-dc converter circuit diagram. Range having input volts and output range Hi Mohammed, I have not yet researched this concept, if possible I'll do it and try to design a suitable circuit with this concept.
Hello sir! You can try the following concept, if you build it correctly step wise it will solve your purpose. Input dc voltage 48volt so, please advice provided circuit is working correctly and how to adjust voltage.
Please provide the 5 second delay timer circuit using ic and operated 12 volt really if on the switch. Please Sir, can someone use laminated transformer I E type for the mppt discussed above?
Thanks Abbey. Hello sir,please may explain a difficulty and ask a question based on it. Say khz. Which will allow the use of awg Reducing wire to Hi Shedrach, It seems you might have missed something, your analysis might be wrong.
However number of turns is related to current, more turn numbers allow less current and vice versa. As I understand it, the LM contains a voltage reference, ten op-amps, and various resistors used as voltage dividers, such that it switches among outputs with varying input voltage. Could the efficiency of the design be improved by placing the inductor taps at regular intervals — or using discrete inductors in series — and replacing the LM with discrete components, chosen carefully to match the inductance values of each connection to the inductor?
If so, could the efficiency be improved further by adding a greater number of outputs, with smaller differences between them? Yes the output will sequence at uniform steps in response to the corresponding increase or decrease in the solar voltage. WE can note down at what input voltages the output shifts, and accordingly dimension the coil data, so that the two operations become compatible with each other. Alternatively we could go for discrete opamp based sensor, as used in this concept:.
Would it become more efficient if you used more steps? LM will do as per its own fixed specs, and this will be uniform across the whose range…I think LM is a better option. Hello annamalai, you can try implementing the first two simple concepts explained above, the transformer winding can be modified as per your charging specifications. Could you accomplish the same effect by using a single op-amp, configured for a precise, low gain, and pairing each BJT with two resistors of precise values, as a voltage divider, chosen to admit the voltage necessary to gate that BJT only when the amp is receiving current from the panel at a particular voltage?
In the above concept, the main MPPT execution is done by the transformer through the matching of its various taps with the solar voltage. With a single opamp we cannot switch the different taps of the transformer and therefore cannot accomplish the required MPPT effect. Hello sir, please help me with the formula to calculate the number of turns and amperage of the above 2 mppt transformers.
Abbey, you can use the second concept from top, it uses an ordinary iron core transformer having multiple primary taps, 3V,4. The secondary output could be V, for low voltage output, you can extract them across the primary taps itself.
Good morning Mr Swagatam, I really appreciate your character of been prompt to reply every questions sent to you, thanks a lot and have a nice day. I am looking to make a MPPT to power the electrodes in a salt water swimming pool chlorinator.
Using a 12 volt panel s would like to feed straight to the electrodes in the chlorinator unit. The electrodes need volts at a current of amps.
Would one of your MPPT circuits be able to achieve this without the battery connection? The MPPT can be switched on by a flow switch situated in the pump supply or discharge line. The inductor based MPPT explained might surely work, however the high frequency transformers are not calculated, and using an iron core trasformer might make the design huge and bulky.
Instead I would recommend using professional and tested buck converter designs which should work as efficiently as an MPPT if the load is not exceeded above a specified level. Here are a few examples:. Which of your article can be used and what modifications is needed? You can try the concept explained in the above article 1st design but for 60 amps the transformer will be huge, unless it is a ferrite based design.
Hi, yes definitely, you can use the last circuit from the above article to charge your 48V battery from a 75V panel. Merry Christmas to you and also wishing a happier and a safer to you. You can definitely try the last circuit for your application. However, TIP might not be sufficient to handle 9 amps…. For transistor it will need to be calculated using the for a as explained in the following article. Hello Engr.
Many thanks for your selfless and invaluable efforts in throwing out for free and demystifying top secret in electronics which other Engineers would have converted into money. Could you give me a simple 12v mppt based charge controller circuit, as updated.
Hi Swagatam, Please can you shed more light on the type of ferrite single long inductor coil used in the diagram? And what is the value of the capacitor in the output? What is the current output rating of the circuit Number 2 diagram? You will have to find it through some trial and error, you can use 1. Hi Swagatam, Really excited to find this!! If so please provide specification. USB 3. Thank you sir. What will happen if a bulk converter is connected directly to Solar panel and then to load without mppt.?
Hi Onyi, Buck converter will work very nicely almost like an MPPT, but you must have an over charge auto cut off for the battery, to prevent over charging. You have not explained anything on the working principles under the MPPT circuit diagram please kindly do that for me sir. The circuit works using the standard step down transformer principle.
The circuit adjusts the transformer tapping with the solar panel voltage and matches them appropriately, so that the right winding gets the right voltage from the solar panel. When this happens the output voltage remains constant, and also output current remains optimally adjusted regardless of the solar panel voltage. Emmanuel, the IC circuit is a complex circuit and you must build it with step step up testing and by understanding the stages perfectly. If you do it without understanding it then it will never work.
For understanding the buck converter you will have to first learn how a buck converter works. Your email address will not be published. Notify me via e-mail if anyone answers my comment.
You'll also like: 1. Then it may be fairest to be honest about that. Hi, Thanks! You are welcome! Does it mean both the transistor emitter points should be connected. The ground points must be connected to battery -ve or solar panel — ve. Mayuresh, you can try the last circuit updated in the above article.
Hai sir, I have two 35vw panel. Can u use this circuit for charging 12v AH Battey? Sir, I am build the ciruit, but the output voltage is around 35 v , what I do? Ajith, did you set the circuit as directed in the article. Now short the output terminals, LEd should light up now. Dear Swagatam, Thank you for providing such brilliant guidance. Thank you dear Mooney, Actually I have never used a simulator in my life because I simply never needed these artificial means, I normally do the simulation in my mind much reliably…so I am afraid I have no idea about these things.
Dear sir, Please send me 48 volt only low dc cut off circuit. Dear sir, Input dc voltage 48volt so, please advice provided circuit is working correctly and how to adjust voltage. Hi Manj, you can use the same circuit for 48V also, just make sure the relay is 48V rated, and use BC, BC instead of BC, BC apply the specified low voltage level from the battery side, and adjust the preset such that the relay just clicks ON….
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