Application of battery management system to photovoltaic industry and control method

Abstract

The invention discloses a battery management system applied to a photovoltaic industry. The battery management system comprises a photovoltaic power supply component, a direct current controller and an inverter, wherein the direct current controller is electrically connected with the photovoltaic power supply component and the inverter; the positive and negative output ends of the direct current controller are connected with a direct current bus respectively; a plurality of charging and discharging units are connected in parallel with the direct current bus; the charging and discharging unit comprises a two-way direct current (DC) / DC converter and a storage battery which are electrically connected with each other; and a master control computer is connected with the direct current controller, the inverter and the two-way DC / DC converters through a 485 communication line respectively. The battery management system is flexible in running, highly efficient and reliable; the overall service life of the battery management system is prolonged; a scale is easy to expand; and modular system integration is easy to realize.

Description

Technical field: [0001] The invention mainly relates to the field of solar photovoltaic power generation, in particular to a battery management system applied to the photovoltaic industry. Background technique: [0002] In an independent solar power generation system, in order to reduce costs, improve efficiency and reliability, it is necessary not only to maximize the output power of photovoltaic cells, but also to correctly charge and discharge batteries, and to maximize the use of generated energy. In the current photovoltaic system, there are contradictions in the realization of the three, and usually only one aspect is considered, such as only tracking the maximum power point of photovoltaic cells and giving up the optimal charge and discharge of batteries, thus limiting the efficiency and life of the system. [0003] At present, maintenance-free lead-acid batteries, as energy storage devices, are widely used in photovoltaic systems due to their advantages of low main...

AI Technical Summary

Problems solved by technology

The output terminal of the DC controller is directly connected to the battery and the inverter. This can avoid overcharging, but it cannot solve the possible undercharging. The battery lacks effective protection and cannot be charged optimally. Reduced lifespan and increased system maintenance costs

In addition, when the output power of photovoltaic cells is large, because the load of the inverter generally does not change randomly, the charging power may be too large within a certain period of time, and the protection circuit needs to be activated to limit the charging intensity, which will inevitably cause energy waste. Indirectly increase the system power generation cost

Similarly, due to the uncertainty of the load, when the battery supplies power alone, all battery cells will be partially discharged, that is, the battery cannot be fully discharged, which is also harmful to the battery.

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