Solar maximum power tracking method and solar charging device

Abstract

The invention discloses a solar maximum power tracking method, which comprises the following steps of: firstly, carrying out global optimizing by using a larger-step-length disturbance method, finding a global maximum power point, tracking the maximum power point by using an incremental conductance method, and absorbing the advantages of the two methods to ensure the correctness of the current maximum power point; and secondly, locking the found maximum power point for eight to ten minutes, and searching the maximum power point for the second time after eight to ten minutes. The invention also discloses a charging device by using the solar maximum power tracking method. A control end of a buck type conversion module of the charging device is connected with a maximum power point tracking (MPPT) core control module; a signal input end of the buck type conversion module is connected with a solar battery; and a signal output end of the buck type conversion module is connected with a storage battery. By the invention, the charging efficiency of the solar battery on the storage battery is improved.

Description

technical field [0001] The invention relates to the technical field of solar energy utilization, in particular to a solar maximum power tracking method and a solar charging device. technical background [0002] In the solar independent system, the current commonly used charging circuit adopts the method of directly coupling the solar cell and the battery. The maximum power point causes the output power to decrease, wasting precious solar energy resources. [0003] In order to save energy and reduce consumption, the MPPT (Maximum Power Point Tracking, Maximum Power Point Tracking) technology adopted to address the defects of traditional charging methods in independent solar energy systems has gradually emerged. At present, the MPPT technology mainly includes the CVT (The conventional Constant Voltage Tracking, constant voltage tracking) method, the disturbance observation method and the incremental conductance method in the solar energy system. Taking the perturbation obser...

AI Technical Summary

Problems solved by technology

Its problems are: 1. The system must introduce disturbances, and the final result of optimization is that the system oscillates back and forth in a small range near the maximum power point.

2. It is difficult to choose an appropriate change step size. If the step size is too small, the tracking speed will be slow. The photovoltaic array may work in a low power area for a long time. If the step size is too large, the vibration near the maximum power point will increase.

The biggest problem it has is that the solar array may have a local maximum power point due to some kind of interference, and this algorithm may cause the system to work stably at a local optimum point

[0007] When the existing MPPT system is working, it is constantly looking for the maximum power point, so that during the search process, a large part of the time works in the non-maximum power range, especially when there are slight changes in light and temperature, the controller will be activated to re-seek, which ultimately results in less time spent working at maximum power point and most of the day in the process of seeking

[0008] In addition, most of the current MPPT algorithms are just a theoretical derivation, and have not been really applied to actual products. Although some of them can find the maximum power point, the hardware circuit implemented is complicated, and the efficiency of the MPPT controller itself is not considered, which eventually leads to an increase Most of the power is lost by itself

Did not achieve the purpose of maximizing the charging efficiency of the photovoltaic system

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