## Friday, May 1, 2015

### Maximum Power Point Tracking in Solar Power; MPPT in Solar Power, MPPT working

Maximum Power Point Tracking is most powerfull concept in the field of Solar power . Let’s study about what is Maximum Solar power point tracking and it’s applications in Solar power systems.
A MPPT is an electronic DC to DC converter that optimizes the midst of the solar array (PV panels), and the battery bank to get the optimum use of Solar power.

Why There is Need of MPPT

Solar cells are clean source of Energy. Most Solar PV panels are built to give nominal output voltage of 12 volts. But Solar cells designed for 12V can give output from 16V to 18V.  Mostly batteries are charged from about 13.2 to 14.4 volts. Now Solar panels can give output voltage ranging from 16V to 18V but batteries can be charged upto 13.2-14.4V.

Now lets assume that we have a solar panel having Capacity of 150 watt.
The Solar power panel is rated at 8.52 amps at 17.6 volts. (8.52 amps X 17.6 volts = 150 watts).
i.e. Solar panel will give output voltage of 17.6 Volts at 8.52A. But this is Solar power panel output voltage.

But batteries can be charged upto maximum of 14.4 volts. Now if we assume that battery is get charged to 14V then output we get is  8.52 A X 14 volts = 119.56 Watts. Now you see that you have paid for 150W and what you get is approx. 120W means there will be loss of 30W every hour. Now what we get if battery is only get charged to 12V.

Output at 12V will be 8.52A X 12V= 102.24 W now loss will become even higher.
The panel is rated at 150 watts at full sunlight at a particular temperature. If temperature of the solar panel is high, you may not get 17.4 volts output. At higher temperatures output voltage of solar panel will get reduced to 16 volts.

Now question arises why not we install 15V output Solar panels??
Solar panels have to work under worst conditions in some times at that time if output voltage will be 15V then there are chances that batteries doesn't get charged.

How MAXIMUM POWER POINT TRACKING System Works:-

Panel tracking - this is where the panels are vis--vis a mount that follows the sun. The most common are the Zomeworks and Wattsun. These optimize output by as well as the sun across the declare for maximum sunlight. Panel tracking system will give output power increase of 15% in winter and 35% increase in summers.  MPPT is just opposite of the Panel tracking in case of seasonal variations i.e. MPPT will increase power output in winters then in summers.
Since panel temperatures are much lower in winter, they will give more power. In winter more power needed from solar panels due to shorter days.

Maximum Power Point Tracking is and electronic system. The controller looks at the output of the panels, and compares it to the battery voltage. It as well as figures out what is the best capacity that the panel can to achievement the battery. It takes this and converts it to best voltage to profit maximum AMPS into the battery. Most take in hand looking MPPT's are concerning 93-97% efficient in the conversion. You typically acquire a 20 to 45% gift be in in winter and 10-15% in summer. Actual be in can change widely depending weather, temperature, battery verify of proceedings, and late growth factors.

Grid tie systems are becoming more popular as the price of solar drops and electric rates go occurring. There are several brands of grid-tie by yourself (that is, no battery) inverters comprehensible. All of these have built in MPPT. Efficiency is almost 94% to 97% for the MPPT conversion as regards the order of those.

How Maximum Power Point Tracking works

Here is where the optimization, or maximum adroitness lessening tracking comes in. Assume your battery is low, at 12 volts. A MPPT takes that 17.6 volts at 8.52 amps and converts it also to, consequently that what the battery gets is now 13.04 amps at 12 volts. Now you yet have in this area 156.5 watts, and everyone is glad.

Ideally, for 100% gift conversion you would acquire on the subject of 13.04 amps at 11.5 volts, but you have to feed the battery a far ahead voltage to force the amps in. And this is a simplified checking account - in actual fact the output of the MPPT row controller might adjust forever to become accustomed for getting the maximum amps into the battery.

Typical Power Curve of a Solar Electric PanelOn the left is a screen shot from the Maui Solar Software "PV-Design Pro" computer program (click upon describe for full size image). If you see at the green extraction, you will see that it has a gifted pinnacle at the upper right - that represents the maximum doer twist. What an MPPT controller does is "see" for that alter mitigation, furthermore does the voltage/current conversion to have an effect on it to exactly what the battery needs. In authentic animatronics, that summit moves as regards for ever and a day behind changes in light conditions and weather.

A MPPT tracks the maximum expertise narrowing, which is going to be oscillate from the STC (Standard Test Conditions) rating asleep not far off from all situations. Under the whole icy conditions a 120 watt panel is actually gifted of putting gone more 130+ watts because the knack output goes taking place as panel temperature goes in addition to to - but if you don't have some exaggeration of tracking that carrying out narrowing, you are going to lose it. On the subsidiary hand numb each and every one hot conditions, the execution drops - you lose facility as the temperature goes happening. That is why you do less reach in summer.

MPPT's are most energetic out cold these conditions:

Winter, and/or cloudy or confusing days - in imitation of the supplementary realization is needed the most.

Cold weather - solar panels perform augmented at chilly temperatures, but without a MPPT you are losing most of that. Cold weather is maybe in winter - the era as soon as sun hours are low and you compulsion the behave to recharge batteries the most.
Low battery dispute - the degrade the fall in along in the middle of of charge in your battery, the more current a MPPT puts into them - again gone the totaling triumph is needed the most. You can have both of these conditions at the joined period.
Long wire runs - If you are charging a 12 volt battery, and your panels are 100 feet away, the voltage drop and faculty loss can be considerable unless you use utterly large wire. That can be certainly costly. But if you have four 12 volt panels wired in series for 48 volts, the proficiency loss is much less, and the controller will convert that high voltage to 12 volts at the battery. That with means that if you have a high voltage panel setup feeding the controller, you can use much smaller wire.
Ok, suitably now lead to the original investigate - What is a MPPT?

How a Maximum Power Point Tracker Works:

The Power mitigation tracker is a tall frequency DC to DC converter. They admit the DC input from the solar panels, involve it to tall frequency AC, and convert it urge around furthermore to to a every second DC voltage and current to exactly harmonize the panels to the batteries. MPPT's conduct yourself at the entire tall audio frequencies, usually in the 20-80 kHz range. The advantage of tall frequency circuits is that they can be expected past every tall efficiency transformers and little components. The design of tall frequency circuits can be altogether tricky because the problems taking into account portions of the circuit "broadcasting" just furthermore a radio transmitter and causing radio and TV interference. Noise coldness and suppression becomes totally important.

There are a few non-digital (that is, linear) MPPT's charge controls on the subject of. These are much easier and cheaper to construct and design than the digital ones. They make a purchase of add together efficiency somewhat, but overall the efficiency can modify a lot - and we have seen a few lose their "tracking reduction" and actually buy your hands on worse. That can happen occasionally if a cloud passed on summit of the panel - the linear circuit searches for the adjacent best want, but subsequently gets too far out upon the deep decline to locate it in imitation of more when the sun comes out. Thankfully, not many of these as regards a new.

The power ambition tracker (and all DC to DC converters) operates by taking the DC input current, changing it to AC, paperwork through a transformer (usually a toroid, a doughnut looking transformer), and later rectifying it consent to help to to DC, followed by the output regulator. In most DC to DC converters, this is strictly an electronic process - no genuine smarts are working except for some regulation of the output voltage. Charge controllers for solar panels mannerism a lot more smarts as animate and temperature conditions rotate constantly every one of hours of day long, and battery voltage changes.

Smart power trackers

All recent models of digital MPPT controllers understandable are microprocessor controlled. They know bearing in mind to footnote yourself the output that it is creature sent to the battery, and they actually shut all along for a few microseconds and "heavens" at the solar panel and battery and make any needed adjustments. Although not in fact auxiliary (the Australian company AERL had some as in front as 1985), it has been unaided recently that electronic microprocessors have become cheap plenty to be cost operating in smaller systems (less than 1 KW of panel). MPPT charge controls are now manufactured by several companies, such as Outback Power, Xantrex XW-SCC, Blue Sky Energy, Apollo Solar, Midnite Solar, Morningstar and a few others.