In recent years we have seen a considerable increase in the installed capacity of Photovoltaic (PV) power generating plants worldwide. This increase is primarily attributed to the decrease in the cost of installation and the awareness towards the sustainable power generation. However, the efficiency of the PV modules is still low. The Current vs. Voltage (I-V) characteristics of the PV generators is non-linear and changes with irradiance and temperature. For optimal utilization of PV sources, Maximum Power Point Trackers (MPPTs) are used. When the array is under uniform illumination, there is a single peak on the Power vs. Voltage (P-V) curve of the PV array. This peak is easily tracked by conventional MPPTs. However, under Partial Shading Conditions (PSC), multiple peaks appear on the P-V curve. Out of these, there is one Global Peak (GP) while the others are Local Peaks (LP). When the MPPT algorithm is trapped at LP, considerable power loss occurs. Special MPPTs are designed for finding the GP when the array is under PSC. It is also important to periodically find the I-V curve of the array under the field conditions for monitoring and control of the PV generators. For this purpose, specialized tests are performed. During these tests, the generation of power from the PV arrays is halted. Similarly, the speed of performance of these tests is also important as the environmental conditions may change quickly during finding of the curve. Any change in the surroundings during the performance of finding the characteristic curve may affect the results. In this thesis, two algorithms are proposed that perform the MPP tracking and measurement of the I-V curve under any kind of irradiance. The first algorithm performs these tasks by using the module voltages as the parameter. In the second method, the input filter capacitor of buck or buck-boost converter is used. Simulation and experimental results confirm the performance of the proposed methods.

A Unified Approach to Maximum Power Point Tracking and I-V Curve Determination of Photovoltaic Arrays from Real-time Measurements / Ahmad, Jawad. - (2017). [10.6092/polito/porto/2674886]

A Unified Approach to Maximum Power Point Tracking and I-V Curve Determination of Photovoltaic Arrays from Real-time Measurements

AHMAD, JAWAD
2017

Abstract

In recent years we have seen a considerable increase in the installed capacity of Photovoltaic (PV) power generating plants worldwide. This increase is primarily attributed to the decrease in the cost of installation and the awareness towards the sustainable power generation. However, the efficiency of the PV modules is still low. The Current vs. Voltage (I-V) characteristics of the PV generators is non-linear and changes with irradiance and temperature. For optimal utilization of PV sources, Maximum Power Point Trackers (MPPTs) are used. When the array is under uniform illumination, there is a single peak on the Power vs. Voltage (P-V) curve of the PV array. This peak is easily tracked by conventional MPPTs. However, under Partial Shading Conditions (PSC), multiple peaks appear on the P-V curve. Out of these, there is one Global Peak (GP) while the others are Local Peaks (LP). When the MPPT algorithm is trapped at LP, considerable power loss occurs. Special MPPTs are designed for finding the GP when the array is under PSC. It is also important to periodically find the I-V curve of the array under the field conditions for monitoring and control of the PV generators. For this purpose, specialized tests are performed. During these tests, the generation of power from the PV arrays is halted. Similarly, the speed of performance of these tests is also important as the environmental conditions may change quickly during finding of the curve. Any change in the surroundings during the performance of finding the characteristic curve may affect the results. In this thesis, two algorithms are proposed that perform the MPP tracking and measurement of the I-V curve under any kind of irradiance. The first algorithm performs these tasks by using the module voltages as the parameter. In the second method, the input filter capacitor of buck or buck-boost converter is used. Simulation and experimental results confirm the performance of the proposed methods.
2017
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2674886
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