Photovoltaic power generation system based on MOSFET (metal-oxide-semiconductor field effect transistor) counter-current prevention

Abstract

The invention discloses a photovoltaic power generation system based on MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) counter-current prevention. The system comprises a storage battery, a control module, at least one photovoltaic cell panel, at least one voltage detection module and at least one MOSFET, wherein only one MOSFET is connected between each photovoltaic cell panel and the storage battery, each voltage detection module is respectively connected with the negative pole of each photovoltaic cell panel, each voltage detection module is also respectively connected with the control module, and the control module is connected with the grid electrodes of the MOSFETs and the voltage detection module. According to the invention, traditional counter-current diodes are replaced with the MOSFETs, because the internal resistance of the MOSFETs in the process of being turned on is small, and greatly lower than the internal resistance of a common diode, thereby greatly reducing the internal loss of energy in the photovoltaic power generation system, and improving the efficiency of the system.

Description

technical field [0001] The invention relates to a photovoltaic power generation system based on MOSFET tube backflow prevention. Background technique [0002] With the rapid development of the photovoltaic industry, photovoltaic power generation is being used more and more. In the photovoltaic power generation system, the photovoltaic panel is connected to the storage battery, and the photovoltaic panel converts solar energy into electrical energy and stores the electrical energy in the storage battery. However, When the solar light is weak, the voltage of the photovoltaic panel is lower than the voltage of the battery, and the current of the battery may flow back into the photovoltaic panel, resulting in waste of battery energy. Even in the parallel array of photovoltaic panels, if one of the photovoltaic modules fails and the output voltage is low, the current output by other normal photovoltaic panels will flow back into the faulty panel, resulting in low output voltage o...

AI Technical Summary

Problems solved by technology

[0002] With the rapid development of the photovoltaic industry, photovoltaic power generation is being used more and more. In the photovoltaic power generation system, the photovoltaic panel is connected to the storage battery, and the photovoltaic panel converts solar energy into electrical energy and stores the electrical energy in the storage battery. However, When the solar light is weak, the voltage of the photovoltaic panel is lower than the voltage of the battery, and the current of the battery may flow back into the photovoltaic panel, resulting in waste of battery energy.

Even in the parallel array of photovoltaic panels, if one of the photovoltaic modules fails and the output voltage is low, the current output by other normal photovoltaic panels will flow back into the faulty panel, resulting in low output voltage of the entire array and energy loss.

The anti-backflow means in the prior art is to connect an anti-backflow diode in series between the photovoltaic panel and the battery, so as to prevent the backflow of current, such as figure 1 Shown is a schematic diagram of a photovoltaic power generation system based on diode anti-backflow in the prior art, but due to the large forward voltage drop of the diode, even a Schottky diode with a lower voltage drop has 0.2 to 0.3V, so the diode anti-backflow is used There are following disadvantages:

[0003] 1. The diode connected in series between the photovoltaic panel and the battery has a forward conduction voltage drop. When using a silicon diode, the voltage drop is generally 0.7V. If a power diode is used, the voltage drop can even reach more than 1V, even if the voltage drop is relatively low. The low Schottky diode also has a voltage drop of about 0.3V, thus greatly reducing the energy utilization efficiency in the photovoltaic power generation system

[0004] 2. Since these diodes connected in series consume a lot of power, the diode becomes a serious heating component in the system, which increases the failure rate of the solar power generation system

[0005] 3. Since the electric energy lost by the series connected diodes is converted into heat, it is necessary to use larger diode devices and cooling elements to dissipate heat, which increases the volume and weight of the system and reduces the mechanical strength of the photovoltaic power generation system

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