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.
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.
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.
To know about Net metering concept in solar System visit link:-http://electrialstandards.blogspot.in/2015/05/net-metering-in-solar-systems.html
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