Solar pv system and mppt
- 1. SOLAR PV SYSTEM AND MPPT TECHNIQUES
- 2. CONTENTS:- 1) INTRODUCTION OF PV SYSTEM 2) TYPES OF PV CELLS 3) SCHEMATIC DIAGRAM OF PV CELLS 4) CHARACTERSTICS OF PV MODULE 5) INTRODUCTION TO MPPT 6) MPPT TECHNIQUES 7) ADVANTAGE OF MPPT TECHNIQUES 8) CONCLUSION
- 3. INTODUCTION OF PV SYSTEM 1)SOLAR PV SYSTEM AND TECHNOLOGY 2) CHARACTERSTICS OF PV MODULE
- 4. SOLAR PV SYSTEM AND TECHNOLOGY PV power generation employs solar panels, composed of a number of solar cells. PV cells are semiconductor devices that convert radiant energy directly into electricity. In simple terms, when sunlight strikes a cell, a certain portion of its energy is absorbed within the semiconductor material. The absorbed energy knocks electrons loose, allowing them to flow freely under the influence of electric fields. The most common PV technology uses solar cells made of semiconductor materials, such as silicon or germanium, dosed with small amounts of impurities.
- 5. ELECTRIC FIELD DEVELOP IN PV CELLS Solar PV cells have inbuilt electric fields that force the free electrons to flow in a certain direction. Metal contacts on the top and bottom of the PV cell, enable the cell to circulate the current in the external circuit. This current, together with the cell's voltage (which is a result of its in-built electric fields), defines the power (or wattage) that a solar cell can produce.
- 6. TYPES OF PV CELLS There are different types of solar PV cells. However, the most common and commercially available types are the mono crystalline, polycrystalline and amorphous cells. The conversion efficiencies of the solarcell manufacture the various technologies are given below(PV Magazine 2017): 1.Mono crystalline– 25% 2.Polycrystalline – 20% 3.Amorphous cells – 13%
- 7. SCHEMATIC DIAGRAM OF PV PLATE
- 8. CHARACTERSTICS OF PV MODULE The current and power outputs of photovoltaic modules are approximately proportional to solar irradiation and the ambient temperature. At a given intensity, a module’s output current and operating voltages are determined by the characteristics of the load. In order to determine the characteristics of the PV module, the Power vs. Voltage (P-V) and Current vs. Voltage (I-V) curves must be constructed. Three parameters, namely, Open Circuit voltage (Voc), Short circuit current (Isc), and Maximum Power Point (Vmp, Imp), are used for the prediction of the PV characteristics of solar PV module. The Typical P-V and I–V characteristics of a PV cell .There is a unique Maximum Power Point (MPP) on the P–V curve, at which the PV cell generates the maximum power. This point is known as the maximum power point (Vmpp, Impp). The value of the maximum powers depends on the environmental factors, such as temperature and irradiation. The maximum power condition always occurs at the knee of the P-V characteristic curve.
- 10. Introduction What is MPPT ? It is an electronic system that operates the photovoltaic modules in a manner to extract the maximum power from the system. What is maximum power point ? It is a operating point at which maximum power can be extracted from the system. Usually represented as MPP. The output of solar module is a function of solar irradiance, temperature. Generally MPPT is installed in between PV system and load. Coupling to the load for maximum power transfer may required either providing a higher voltage at lower current or lower voltage at higher current.
- 11. Different MPPT techniques There are different techniques used to track the maximum power point. Few of the most popular techniques are: 1) Perturb and Observe (hill climbing method) 2) Incremental Conductance method 3) Fractional short circuit current 4) Fractional open circuit voltage 5) Neural networks 6) Fuzzy logic
- 12. Perturb & Observe methodPerturb & Observe (P&O) is the simplest method. In this we use only one sensor, that is the voltage sensor, to sense the PV array voltage and so the cost of implementation is less and hence easy to implement. The time complexity of this algorithm is very less but on reaching very close to the MPP it doesn’t stop at the MPP and keeps on perturbing on both the directions. When this happens the algorithm has reached very close to the MPP and we can set an appropriate error limit or can use a wait function which ends up increasing the time complexity of the algorithm. However the method does not take account of the rapid change of irradiation level (due to which MPPT changes) and considers it as a change in MPP due to perturbation and ends up calculating the wrong MPP. To avoid this problem we can use incremental conductance method.
- 13. Perturb and observe( hill climbing) 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 operated by periodically incrementing or decrementing the solar array voltage. In this we use only voltage sensor, to sense the PV array voltage. Hill climbing method fail under rapid environment change conditions.
- 15. Perturb and observe( hill climbing)
- 16. Incremental Conductance Incremental conductance uses two voltage and current sensors to sense the output voltage and current of the PV array Here we are sensing both current and voltage simultaneously. Hence the error due to change in irradiance is eliminated. However the complexity and cost of implementation increases. Based on fact that slope of P-V 𝑑𝑝/𝑑𝑣 =0 at Mpp 𝑑𝑝/𝑑𝑣 >0 at left Mpp 𝑑𝑝/𝑑𝑣 <0 at right Mpp
- 21. System Modeling MPPT block scheme
- 22. 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!
- 23. Conclusion In this presentation a detailed analysis of various maximum power point tracking algorithms were carried out. Incremental Conductance algorithm which holds good performance than any other methods under normal and varying atmospheric conditions. Power output obtained from incremental conductance method is high us compared to other methods under varying atmospheric conditions. Maximum Power Point Tracking algorithm which place a major role for a grid connected Photo voltaic system. A most suitable MPPT technique is chosen based on the implementation cost, number of sensors required, complexity. So for residential and industrial purposes INCREMENTAL CONDUCTANCE ALGORITHM performs better
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