Photovoltaic maximum power point tracking method based on volt-ampere characteristic equation and dichotomy

Abstract

A photovoltaic maximum power point tracking method based on a volt-ampere characteristic equation and a dichotomy method belongs to the technical field of solar photovoltaic power generation. The method includes: the sampling module collects the output current and output voltage value of the current photovoltaic array, the MPPT calculation module and the PWM drive module calculate the maximum power point voltage value, and control the boost booster module to make the system output power reach the maximum . The invention adopts the complex nonlinear volt-ampere characteristic equation, the parameter value of the battery panel in the standard state, the voltage and current value collected twice, etc., combined with the bisection method to carry out numerical calculation, so as to obtain the current short-circuit current and open-circuit voltage. , temperature, and the voltage and current values ​​of the maximum power point; it solves the problems of misjudgment, power loss, and system oscillation in the disturbance process of the traditional method.

Description

technical field [0001] The invention belongs to the technical field of solar photovoltaic power generation, and in particular relates to a photovoltaic maximum power point tracking method based on a volt-ampere characteristic equation and a dichotomy method. Background technique [0002] Currently, due to low conversion efficiency and high cost of solar photovoltaic products, they have not been widely popularized and applied. The maximum power point tracking (MPPT) technology is an effective way to improve the efficiency of photovoltaic power generation. The commonly used MPPT methods can be divided into the following three categories: disturbance incremental method, intelligent incremental method, and derivation dp / de method. The disturbance increment method refers to the method of gradually approaching the maximum power through continuous sampling. The advantage of this method is that the algorithm is simple, but the disadvantage is that the selection of the initial value ...

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Problems solved by technology

The disturbance increment method refers to the method of gradually approaching the maximum power through continuous sampling. The advantage of this method is that the algorithm is simple, but the disadvantage is that the selection of the initial value and the step size have a great impact on the tracking accuracy and speed, and cannot adapt to the amount of sunlight. Rapid changes, and may oscillate near the maximum power point of the array, resulting in partial power loss, and sometimes the disorder of program control during operation, resulting in misjudgment; intelligent incremental methods include fuzzy control method neural network control method, fuzzy control method The control method establishes a fuzzy rule between the sunshine change and the conduction rate to improve the influence of the sunshine change on the system. The advantage is that the maximum power point can also be found when the sunshine changes sharply. The disadvantage is that the continuous sampling process will still cause the system Oscillation phenomenon, the neural network control method needs to extract a large number of samples, which cannot reach the actual application process; the derivation dp / de method is a relatively common method at present, by calculating the derivative of power and voltage and the tube when it is turned on and off The relationship between various parameters, adjust the size of the conduction rate, and the maximum power can be reached when the derivative of power to voltage is zero. The advantage of this method is that the fluctuation near the maximum power point is small and can achieve high accuracy. The disadvantage is The algorithm is complex, there are many parameters to be determined, and the parameter values ​​are difficult to determine

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