High-frequency isolation conversion energy storage system

Abstract

The invention discloses a high-frequency isolation conversion energy storage system, which comprises high-frequency isolation conversion two-way DC / DC conversion devices and a direct current bus, wherein a first connecting point of each two-way DC / DC device is connected with an energy storage device; a second connecting point is connected to the direct current bus; through the two-way DC / DC devices, electric energy in the energy storage devices can be subjected to two-way alternating with the direct current bus through high-frequency isolation conversion. A plurality of energy storage devicesare isolated from the high-frequency isolation transformers of the two-way conversion devices subjected to high-frequency isolation from the direct current bus; the electric energy passing through a transformer is limited, so that the fault current of the direct current bus is reduced; the goal of safe protection is achieved; the plurality of groups of energy storage devices are connected with thebus through respectively independent two-way isolation conversion devices; the differences among different energy storage devices cannot generate mutual influence; the energy storage devices with different properties can even be used in a combined way.

Description

technical field [0001] The invention relates to a high-frequency isolated energy storage system, in particular to a high-frequency isolated and transformed energy storage system. Background technique [0002] When multiple energy storage devices are connected to other systems, due to the different voltages of a single energy storage device, the voltages of internal units are unbalanced, resulting in multiple energy storage devices that cannot be directly connected in parallel, or there are hidden dangers in long-term use in parallel. Especially lithium-ion batteries, when forming a large-scale energy storage system, there are too many series and parallel batteries, and the imbalance of batteries has become a technical bottleneck for its large-scale energy storage use. [0003] What is more prominent is that when retired batteries are used as energy storage, the differences between different battery packs are greater, and they cannot be directly used in parallel, and their ch...

AI Technical Summary

Problems solved by technology

The traditional solution is to add an isolation transformer on the AC side of the inverter system. Due to the low frequency, the electric energy passing through the transformer is still very large. However, in the DC bus, there is no effective way to limit the electric energy released by the energy storage device.

[0005] For charging and discharging applications with impact characteristics, there is a limit to directly adopting one energy storage method

For example, as a high-current charging for energy recovery, the cost or volume of directly using a battery is relatively large. The solution is to use a combination of different energy storage methods. High-rate short-term energy storage uses super capacitors or large-rate energy storage batteries. Energy storage is combined with general lithium-ion batteries, which cannot be flexibly converted into energy

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