| Under the dual pressures of the energy crisis and environmental pollution, photovoltaic power is becoming one of the hottest issues around the world. PV modules are an important part of photovoltaic power generation system. Its output characteristic determines the actual working conditions of system. Since the physical model and experimental environment of PV modules is complex and volatile, simulation experiment is a common method to study the output characteristics. Simulation is usually based on the data of standard reference condition (SRC) provided by the manufacturer. But in the simulation process, we found that the parameters provided by the manufacturer do not adapt to the requirements of simulation due to various reasons. Under this premise, this paper complete the simulation modeling based on the parameters extracted from experimental results.Firstly, this article discusses the significance of the experiment, introduces the detailed devices, designs and processes of the experiment. Measured open circuit voltage, short circuit current, voltage and current at the maximum power point of PV modules under certain light intensity and temperature. Obtained performance parameter values mentioned above based on the data of SRC provided by the manufacturer using the relationship between performance parameter and external environment. Comparing the experimental results and the calculated results, we found that there is a huge gap between them which proves the necessity of determining the parameters by experimental method.Secondly, this article introduced the current status in the research of photovoltaic cells’ mathematical models, and also analyzed the advantages and disadvantages of commonly used mathematical models in the world. The model parameters of five parameters model and four parameters model were obtained by calculating nonlinear equations in MATLAB based on SRC parameters and experimental results. According to the results, both of models own complex calculation process and multiple iterations. Also, we found that there are some problems in the simulation based on SRC parameters. We also make deviation analysis about simulation results with maximum power point as the dividing point, and find that both of models can meet the engineering requirements. Based on the relationship between the model parameters and temperature, light intensity, we also predicted the output characteristic curves of PV modules under different light intensities and temperatures. Comparing with the experimental results at some key data points, we found the predictive curves have satisfied the requirements of engineering applications.Finally, shape parameters model with fewer iterations was also studied, we described the simulation process of shape parameters model, analyzed the impact of two shape parameters on output characteristic curves, built the normalized output characteristic curves based on shape parameters model. According to shape parameters, we calculated a new set of physical parameters, and then built five parameters model based on them. Comparing with original five parameters model, we find that the new model has smaller deviation in the the closed to short circuit current point part.. By comparing the various models, conclusions are as follows:Modeling process of five parameters model is rigorous as it contact with the physical parameters of PV modules closely. But there are more calculation error as the modeling process is complex. Shape parameters can be calculated more accurately as there is fewer iterations during modeling process. But the simulation results are imprecise as the model is oversimplified. After a combination of the both mentioned above, accuracy of the left side of the maximum power point is improved as shunt resistor can be calculated more accurately. But accuracy of ideality factor is reduced as the approximate calculation of ideality factor during modeling, thereby reduced accuracy of the right side of the maximum power point. |
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