Photovoltaic solar charging control device with zero loss and realization method thereof

Abstract

The invention relates to the field of technologies for controlling photovoltaic solar energy to charge batteries, and in particular relates to a photovoltaic solar charging control device with zero loss and a realization method thereof. The device comprises a solar panel, a diode, a transistor, a battery and two mechanical relays A and B. In the device, two ends of the diode for preventing back discharge are connected with the controlled mechanical relay A in parallel, so that a charge current can flow through a contact of the mechanical relay A directly rather than flowing through the diode in a return circuit when the system works, thus the diode is not subjected to tube voltage drop loss. For the purpose of improving the reliability of the solar charging system, a charging voltage is controlled by parallel combination of the controlled mechanical relay B and the transistor rather than a working control mode of a switching power supply, thus the system can not only capture an opportunity that normal sunlight is utilized to charge the battery but also eliminate reactive loss caused by controlling devices of the transistor in the return circuit, thereby reaching the zero loss control effect.

Description

technical field [0001] The invention relates to the field of photovoltaic solar energy charging control technology for storage batteries, in particular to a photovoltaic solar energy charging control method capable of realizing zero loss. (Background technique) [0002] With the increasingly serious energy crisis and the greenhouse effect, the country's industries are gradually turning to energy conservation and emission reduction. Among them, the application of solar energy development is an important part of the energy saving and emission reduction, and also an important part of renewable energy, and has gradually become a hot spot and mainstream of green energy. [0003] Existing solar systems generally include solar cells, solar controllers and storage batteries. [0004] There are currently two types of photovoltaic solar cell charging control methods for batteries, one is on / off control, refer to figure 1 , in the photovoltaic solar energy charging control system f...

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Problems solved by technology

[0005]The problems of this kind of design method are: ① Due to the anti-reverse charging diode exists in the positive circuit, there is a certain voltage drop of the diode during the charging process, which will It consumes a certain amount of electric energy. For the photoelectric conversion project with low conversion efficiency, the cost of the project will be increased to achieve the same effect; ② The switch in the negative circuit is mainly to control the charging voltage of the battery to be charged. Commonly used control devices are relays or transistors. Although relay control has no loop loss, it must require a large voltage difference between the charging off point (full charge) and the charging recovery point (the battery will naturally fall after stopping charging). If the voltage at the off point If the difference between the voltage value and the recovery point is too small, it will cause the relay to switch and jump too frequently, which will reduce the life of the system. However, if the voltage difference is increased, the battery voltage will not reach the recovery point and will not be charged, so it is easy to miss the sun. The best charging opportunity when the light is normal; and the transistor control does not have the problem of affecting the life of the system due to switching, but the tube consumption will be generated when the transistor is turned on and charged, which is also not ideal

[0007]The problem with the pulse width modulation control design method is: due to the switching power supply mode, the failure rate of the switching power supply is relatively high, which reduces the reliability of the system

[0008]In addition, germanium tubes are usually used in the solar charge control system to prevent reverse discharge. For a 10-ampere charge control system, the diode to prevent reverse discharge The loss is as high as 2-5 watts. At present, the price of solar panels is 10-30 yuan / watt. In addition, the price of germanium diodes that can withstand 10 amperes is also very expensive.

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