Photovoltaic microgrid system with function of storing energy

Abstract

The invention relates to a photovoltaic microgrid system with a function of storing energy. The photovoltaic microgrid system comprises a solar cell plate, a storage cell, a bidirectional power converter, a local load and a grid-connection switch, wherein a first selector switch is arranged between the solar cell plate and the bidirectional power converter; and a second selector switch is arranged between the storage cell and the bidirectional power converter. In the photovoltaic microgrid system, functions of photovoltaic grid-connected power generation, storage cell grid-connected energy storage, storage cell grid-connected discharging and storage cell island discharging can be realized by adopting the same bidirectional power converter, so that the system structure is simplified and the cost is reduced; furthermore, as the bidirectional power converter is formed by combining three totally independent single-phase power conversion units, the balance of three phases of output voltage can be guaranteed through independent control of the single-phase power conversion unit in an island state when the storage cell supplies power to the local load, particularly when three phases of local loads are unbalanced severely.

Description

technical field [0001] The invention relates to a micro-grid system, in particular to a photovoltaic micro-grid system with energy storage function. Background technique [0002] Microgrid is the abbreviation of microgrid. Microgrid is a concept relative to traditional large power grid. It is a network composed of multiple distributed power sources and their related loads according to a certain topology, and connected to the conventional power grid through switches. From the perspective of the grid side, a microgrid can be equivalent to a controllable power source or load, which can obtain energy from the grid, and even provide energy to the grid when the power supply of the grid is insufficient. [0003] There are two typical operation modes of the microgrid: under normal circumstances, the microgrid runs in parallel with the conventional grid, which is called the grid-connected mode. The grid and the microgrid work together to supply power to the loads in the microgrid; W...

AI Technical Summary

Problems solved by technology

In the existing scheme, the battery charging and discharging power converter is composed of a three-phase bridge inverter as the core, and the balance of the three-phase output voltage cannot be guaranteed when the battery supplies power to the local load in the island state, especially in the three-phase When the local load is seriously unbalanced, this is a fatal flaw of the existing scheme

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