Photovoltaic microgrid system and control method thereof

Abstract

The invention discloses a photovoltaic microgrid system and a control method thereof. The photovoltaic microgrid system comprises a photovoltaic power generation system, and a photovoltaic energy storage system. The photovoltaic power generation system comprises a photovoltaic panel and a photovoltaic inverter. The photovoltaic energy storage system comprises an energy storage battery, a current sensor and a DC / DC module. The first end of the DC / DC module is connected with the output end of the photovoltaic panel. The second end of the DC / DC module is connected with the energy storage battery.The third end of the DC / DC module is connected with the direct-current side of the photovoltaic inverter through the current sensor. The DC / DC module is used for calculating the output power of the photovoltaic inverter according to the output voltage of the photovoltaic panel and the current of the direct-current side of the photovoltaic inverter, and adjusting the working state of the photovoltaic energy storage system according to the output power of the photovoltaic inverter, the output voltage of the photovoltaic panel and the SOC of the energy storage battery. The system is simple in structure and good in autonomy. The alternating current harmonic of the power grid and the photovoltaic inverter is not influenced at all, and the energy utilization rate of the photovoltaic panel is high.

Description

technical field [0001] The invention relates to the technical field of photovoltaic microgrids, in particular to a photovoltaic microgrid system and a control method thereof. Background technique [0002] As a green energy, solar energy is an inexhaustible clean energy. Using solar energy for photovoltaic power generation can greatly reduce the dependence on fossil energy and reduce the environmental pollution caused by the use of fossil energy. However, photovoltaic power generation is affected by light and temperature. When the external environment changes rapidly, the photovoltaic power generation power will also change rapidly, so that the stable output power to the grid cannot be guaranteed. [0003] In order to make the output power of photovoltaic power generation smoother, an energy storage system can be added to the photovoltaic power generation system. At present, the photovoltaic energy storage system is connected to the AC side of the photovoltaic inverter and ...

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Problems solved by technology

[0004] However, because the energy storage system is connected to the AC side of the photovoltaic inverter, the system output power is limited by the rated power of the photovoltaic inverter, and cannot be applied to the situation where the power generated by the photovoltaic panel is greater than the rated power of the photovoltaic inverter. It will cause waste of photovoltaic energy; at the same time, when the energy storage system is connected to the AC side, it will affect the AC harmonics of the grid and photovoltaic inverter

In addition, for the charging and discharging control strategy of the above technology, since the battery needs to absorb the power generated during the photovoltaic power generation period, the capacity of the battery needs to be large to meet the requirements of energy storage

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