Photovoltaic system MPPT (maximum power point tracking) control method based on adaptive prediction

Abstract

The invention discloses a photovoltaic system MPPT (maximum power point tracking) control method based on adaptive prediction. The method adds an adaptive prediction mechanism to the conventional disturbance observation method, samples the photovoltaic array voltage at multiple moments at present and in the past, predicts the photovoltaic array output power at the next moment by use of the adaptive prediction mechanism, and judges the disturbance direction of the photovoltaic array voltage in advance in combination with the disturbance observation method so as to increase the tracking speed; and meanwhile, the method considers the control precision of the system, reduces the power loss and realizes quick and stable control on the photovoltaic system MPPT. The control method overcomes the shortcomings of slow tracking, low stability, complicated control and the like of the conventional MPPT algorithm, and inhibits the misjudgment phenomenon in the environment with low irradiance and quick change of irradiance. The control method is simple and easy to realize through software programming, can effectively improve the efficiency of the photovoltaic power generation system, and has a great application value in a photovoltaic system.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic power generation system control, in particular to a photovoltaic system maximum power point tracking (MPPT) control method based on self-adaptive prediction. Background technique [0002] With the intensification of world energy problems, photovoltaic power generation technology occupies an increasingly important position in new energy technologies. Effectively reducing the cost of photovoltaic systems and improving system power generation efficiency are the focus of current research. Because solar cells are easily affected by external environmental factors, resulting in power loss, so in the field of control, maximum power point tracking will be the most direct and effective way to reduce power generation costs and improve power generation efficiency. The traditional MPPT algorithm includes several methods such as constant voltage tracking (CVT) method, power feedback method, incremental co...

AI Technical Summary

Problems solved by technology

Among them, the CVT method cannot track the changes in the sunshine intensity and the temperature of the photovoltaic array, and is not a real MPPT control method; the power feedback method is actually a reverse reasoning process of the disturbance and observation method. Since a single power corresponds to multiple voltage and current values, its The stability is affected to a certain extent; when the external environment changes rapidly, the conductance incremental method has better dynamic performance and tracking characteristics than the perturbation and observation method, but its structure is complex and difficult to implement; the perturbation and observation method is currently the most commonly used MPPT control method. Algorithm, by periodically applying disturbance to the output voltage of the photovoltaic array, and comparing the output power of the photovoltaic array before and after the disturbance, so as to determine the correct disturbance direction

However, the perturbation and observation method cannot take into account both tracking speed and control accuracy. At the same time, the system's response ability to external environment changes is poor. In addition, the MPPT control algorithm is a process of continuous optimization, which is prone to direction misjudgment due to external environment interference.

[0003] Aiming at the shortcomings of the traditional MPPT algorithm, many studies have improved the traditional MPPT algorithm, such as using fuzzy control, variable step size MPPT control, etc. Through the analysis of these improved algorithms, we can see that these improved algorithms currently exist Some algorithm complex problems, or there is room for improvement in control accuracy and tracking speed, and it cannot solve the misjudgment phenomenon in the tracking process well

Images