The document discusses maximum power point tracking (MPPT) for photovoltaic systems. It begins with an introduction to MPPT and explains that MPPT is an algorithm included in solar charge controllers to extract the maximum available power from PV modules under different operating conditions. It then provides details on various MPPT techniques like perturb and observe method and incremental conductance method. The document also presents the mathematical model and system modeling of an MPPT system and discusses the advantages of using MPPT to increase energy extraction from solar panels.
3. INTRODUCTION
MATHEMATICAL MODEL
WHAT IS MPPT
HOW IT WORKS
MPPT TECHNIQUES
SYSTEM MODELING
ADVANTAGES
CONCLUSION
4. PV modules still have relatively low conversion
efficiency; therefore, controlling maximum
power point tracking (MPPT) for the solar array
is essential in a PV system. The amount of
power generated by a PV depends on the
operating voltage of the array. A PV’s maximum
power point (MPP) varies with solar insulation
and temperature.
5. MPPT or Maximum Power Point
Tracking is algorithm that included in
charge controllers used for extracting
maximum available power from PV
module under certain conditions. The
voltage at which PV module can
produce maximum power is called
‘maximum power point’ (or peak power
voltage).
WHAT IS MPPT?
7. I= Isc – Io{exp[ q(V + RsI)/(nkTk) ]- 1} – (V+RsI)/Rsh
………………..(1)
Where , Isc = Id + I
The above equation is used in computer
simulations to obtain the o/p characteristics of a
solar cell.
8. Output characteristics of a solar cell are non- linear and are
crucially influenced by a solar radiation, temperature and load
condition.
V-I and V-P characteristics of a solar cell:
9. The major principle of MPPT is to extract the maximum available
power from PV module by making them operate at the most efficient
voltage (maximum power point).
MPPT checks output of PV module, compares it to battery voltage
then fixes what is the best power that PV module can produce to
charge the battery and converts it to the best voltage to get
maximum current into battery.
How MPPT works?
MPPT is most effective under these conditions:
• Cold weather, cloudy or hazy days: Normally, PV module works better at cold
temperatures and MPPT is utilized to extract maximum power available from
them.
•
When battery is deeply discharged: MPPT can extract more current and
charge the battery if the state of charge in the battery is lowers.
10. A MPPT solar charge controller is the charge controller
embedded with MPPT algorithm to maximize the amount
of current going into the battery from PV module.
MPPT is DC to DC converter which operates by taking DC
input from PV module, changing it to AC and converting it
back to a different DC voltage and current to exactly
match the PV module to the battery.
Examples of DC to DC converter are
• Boost converter
• Buck converter
MPPT algorithm can be applied to both of them
depending on system design.
MPPT solar charge controller:
11. MPPT solar charge
controllers are useful for
off-grid solar power
systems such as stand-
alone solar power system,
solar home system and
solar water pump system,
etc.
MPPT solar charge controllers
13. MPPT TECHNIQUES:
Fractional Open-CircuitVoltage
Fractional Short-Circuit Current
Perturb and Observe
Incremental Conductance
14. Fractional Open-Circuit Voltage:
VMPP ≈ k1VOC ……………….(2)
Factor k1 has been reported to be between
0.71 and 0.78.
Implementation of this method is simple.
Its tracking efficiency is relatively low.
15. Fractional Short-Circuit Current:
IMPP ≈ k2 ISC …………………(3)
k2 is not constant. It is found to be between 0.78
and 0.92.
The accuracy of the method and tracking efficiency
depends on the accuracy of K2 and periodic
measurement of short circuit current.
16. Perturb and Observe:
The concept behind the P&O method is to modify
the operating voltage or current of the PV panel
until you obtain maximum power from it.
The tracker operates by periodically incrementing
or decrementing the solar array voltage.
If increasing the voltage to a panel increases the
power output of the panel, the system continues
increasing the operating voltage until the power
output begins to decrease.
18. Incremental Conductance:
Incremental conductance considers the fact that the
slope of the power-voltage curve is zero at the
maximum power point, positive at the left of the
MPP, and negative at the right of the MPP.
ΔI/ΔV = - I/V , at MPP
ΔI/ΔV > - I/V , left of MPP
ΔI/ΔV < - I/V , right of MPP
22. Digital Controller
The microcontroller
provides the control in
our system.
The choice of
microcontroller for the
system dictates much of
the cost, performance,
and flexibility of the
entire system.
25. ADVANTAGES:
MPPT method can extract maximum available
power from the PV module.
This can increase the tracking efficiency.
If your energy use is greatest in the winter (typical
in most homes) and you have cold winter
weather, then you can gain a substantial boost in
energy when you need it the most!
26. CONCLUSION:
A PV systems are suitable for residential and/or
industrial applications as it provides a regulated AC
output voltage that may also track the input mains
utility voltage in phase and amplitude at hundreds to
thousands of watts. Thus MPPT system can be
deployed to get maximum amount of power to take
advantage of solar energy.
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E. Koutroulis; et. al , “ Development of a Microcontroller-based
Photovoltaic maximum power tracking control system”, IEEETrans.On
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pp. 147-153, 2005.
S. Jain andV. Agarwal, “A New Algorithm for RapidTracking of
Approximate Maximum Power Point in Photovoltaic Systems,” IEEE
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method for photovoltaic power systems,” 35th. Annual IEEE Power
Electron. Specialists Conf. , pp. 1957-1963, 2004.
Y. Kuo, et. Al., “Maximum power point tracking controller for photovoltaic
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