Countercurrent-resisting control method and device and countercurrent-resisting system thereof

Abstract

The invention relates to a countercurrent-resisting control method applied to a grid-connected photovoltaic power generation system, a device and a countercurrent-resisting system using the method and the device. When power P1 of an access point of a grid is less than preset countercurrent specified power P0, countercurrent occurs, and a countercurrent-resisting controller turns down output power of a distributed power source, until the power source is shut down. When the power P1 of the access point of the grid is larger than the preset countercurrent specified power P0, output power of the distributed power source is too low and can not meet the demand on local load, electricity need taking from the grid, the countercurrent-resisting controller turns up the output power of the distributed power source, and power generation capacity of the distributed power source is increased. The countercurrent-resisting control method, the device and the countercurrent-resisting system thereof prevent from generating countercurrent, simultaneously improve power generation capacity of the distributed power source, reduce impact on the grid, and prolong service life of the distributed power source.

Description

technical field [0001] The invention belongs to the anti-backflow technology in the field of distributed power generation, and in particular relates to an anti-backflow control method and device applied in a photovoltaic grid-connected power generation system, and an anti-backflow system using the method and device. Background technique [0002] In the photovoltaic grid-connected power generation system, the photovoltaic grid-connected system is usually required to be a non-reverse current power generation system, that is, the electricity generated by the photovoltaic grid-connected system is consumed by the local load to avoid grid instability and harmonic generation. With the country's support for photovoltaic power stations, there are more and more photovoltaic grid-connected power stations. Therefore, a reliable anti-backflow system is needed, and at the same time, the photovoltaic power generation system can maximize the output power. [0003] The existing anti-backflow...

AI Technical Summary

Problems solved by technology

The long-term connection to the grid is considered in the design of photovoltaic grid-connected power supplies. If frequent cut-offs not only have a great impact on the grid, but also affect the life and safe operation of the photovoltaic grid-connected system

In addition, due to the characteristics of MPPT (maximum power point) search for photovoltaic inverters, once the photovoltaic grid-connected power supply is cut off and reconnected to the grid, it takes 1 to 5 minutes to reach the normal working state, and when the load power is less than the output power of the photovoltaic grid-connected power supply When the photovoltaic grid-connected power supply is cut off, it will not be able to output part of the power, resulting in a reduction in the power generation of the photovoltaic grid-connected system.

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