The invention discloses a seven-parameter photovoltaic cell output characteristic modeling method based on an STFT (Short Time Fourier Transform) operator. The method comprises the steps of establishing an equivalent circuit initial model of photovoltaic cell output characteristics; defining the STFT operator to obtain a decoupling explicit equation parameter model of a photovoltaic cell; establishing a nonlinear equation set by using standard working condition basic data provided by a photovoltaic cell manufacturer, and calculating unknown parameters by using a solution algorithm; calculating unknown parameter values of the decoupling explicit equation parameter model under given working conditions; bringing the unknown parameter values under the given working conditions in the decoupling explicit equation parameter model of the photovoltaic cell to obtain a final photovoltaic cell model which comprehensively reflects photovoltaic cell output characteristics under the given working conditions. The method has the beneficial effects that the STFT operator adopted for model decoupling is not limited by a domain of definition, the expected STFT decoupling operator calculation accuracy can be set according to the needs, and the application is more flexible.

Seven-parameter photovoltaic cell output characteristic modeling method based on STFT (Short Time Fourier Transform) operator

The invention discloses a Bezier-based polynomial photovoltaic array maximum power tracking method. The method includes: during the process of measuring actual irradiance and temperature value of a photovoltaic array, calculating maximum power point parameter of a photovoltaic array, acquiring an output characteristic curve of the same, and performing polynomial fitting to obtain a fitting result;according to an incremental conductance method and voltage and current measured in real time, slightly adjusting a maximum power point acquired through theoretical calculation, and taking a voltage value acquired by detection as an independent variable to enable working output characteristics of a photovoltaic module to be at maximum power point voltage after slight adjusting and to enable the photovoltaic module to work at maximum output power to realize maximum power tracking of the photovoltaic array. The method can realize effective maximum power tracking and has the advantages of being simple to realize and high in tracking accuracy.

Bezier-based polynomial photovoltaic array maximum power tracking method

The invention discloses a photovoltaic cell output characteristic modeling method based on a Bezier function. The method comprises the steps of S1, establishing a rectangular plane coordinate system, determining the positions of a short-circuit current point, a maximum power point and an open-circuit voltage point in the rectangular plane coordinate system, and determining the positions of two control points of the Bezier function in the rectangular plane coordinate system according to the positions of the short-circuit current point, the maximum power point and the open-circuit voltage point; S2, determining the coordinates of points, located on the left side and right side of the maximum power point, on the Bezier function curve according to the positions of the short-circuit current point, the maximum power point, the open-circuit voltage point and the two control points; S3, drawing a Bezier fitted curve. According to the method, photovoltaic cell output characteristic modeling can be achieved simply based on the parameters including short-circuit current, maximum power point and open-circuit voltage given by a manufacturer by means of the piecewise second-order Bezier function.

Shi Nan

Papers

Photovoltaic cell output characteristic modeling method based on Bezier function