Maximum power estimation method for photovoltaic power generation system

Abstract

The invention provides a maximum power estimation method for a photovoltaic power generation system. The maximum power estimation method comprises the steps of establishing a double-diode 7 parametermodel of a photovoltaic cell, and realizing conversion calculation from environmental parameters to standard conditions by adopting open-circuit voltage and short-circuit current parameters; and usingan L-M algorithm controlled by parameters, so that the algorithm shows the characteristics of a gradient descent method and a Gauss-Newton method in sections, and the advantages of the two methods are fully combined. Photovoltaic double-diode model parameter calculation based on the L-M algorithm is less affected by iterative initial value selection, and convergence speed and precision are increased. The maximum power value is obtained based on an open-circuit voltage approximation method. The process of one-time iteration is omitted, and the calculation speed is increased.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic power generation, and in particular relates to a method for estimating the maximum power of a photovoltaic power generation system based on a double diode model and an LM algorithm. Background technique [0002] As an important renewable energy power generation technology, photovoltaic power generation occupies an important position in the future energy development. With the gradual increase in the proportion of photovoltaic power generation, the power grid has put forward higher and higher requirements for the controllability of photovoltaic power generation systems. Estimating the maximum power of photovoltaic power generation system, the maximum output power of photovoltaic power can be obtained by numerical calculation method, which is convenient for the power grid to issue dispatching instructions and control, and prevent the excessive fluctuation of the output power of photovoltaic powe...

AI Technical Summary

Problems solved by technology

The maximum power estimation (Maximum PhotovoltaicPower Estimation, MPPE) of the photovoltaic power generation system needs to model and analyze the photovoltaic cells and modules. The photovoltaic single diode model (also known as the five-parameter model) is more accurate and less difficult to calculate. It is widely used, but its accuracy will be greatly reduced in the case of low solar radiation and open circuit voltage. The photovoltaic double diode model compensates for the recombination loss by connecting another diode in parallel in the single diode model to improve the modeling accuracy.

However, the dual-diode model is a seven-parameter model that needs to be solved for seven parameters. Since the photovoltaic output characteristic is a nonlinear transcendental equation, there is a greater risk of iteration failure during the solution process. The traditional linear approximation method will bring large errors in low-radiation environments. The prediction accuracy cannot be guaranteed, and it is difficult to ensure both the iterative convergence and the accuracy of the solution during the solution process

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