CN111555322A

CN111555322A - Energy storage system

Info

Publication number: CN111555322A
Application number: CN202010318947.2A
Authority: CN
Inventors: 吴志猛
Original assignee: Shenzhen Hopewind Electric Co Ltd
Current assignee: Shenzhen Hopewind Electric Co Ltd
Priority date: 2020-04-21
Filing date: 2020-04-21
Publication date: 2020-08-18

Abstract

The application discloses energy storage system, including the isolation transformer who is connected with the electric wire netting, isolation transformer still is connected with one or more AC switch cabinet, AC switch cabinet is connected with one or more DC/AC converter, every DC/AC converter all is connected with one or more group battery. The alternating current switch cabinet is connected with one or more DC/AC converters, and each DC/AC converter is connected with one or more battery packs; the circulation problem generated by the parallel connection of multiple branches of the battery pack is eliminated, the application flexibility of the energy storage system is improved, and the competitiveness of the product is improved.

Description

Energy storage system

Technical Field

The application relates to the technical field of power electronics, in particular to an energy storage system.

Background

The energy storage converter is matched with the energy storage battery pack, is connected between the battery pack and a power grid, stores the electric energy of the power grid into the battery pack or feeds the energy of the battery pack back to the power grid, and mainly comprises a bidirectional power converter and a control system thereof.

As shown in fig. 1, an energy storage system in the prior art is composed of a battery pack, a battery management system, a converter and an energy management system. Although the batteries are various, the energy storage system adopts a one-level structure, current only needs DC/AC conversion, the energy conversion efficiency is high, the problem of circulation current is easily caused by multipath parallel connection of the battery packs, the adaptability of the system to direct current voltage is poor, and the cost of the energy storage system is increased due to the fact that the batteries of the same converter are required to have the same specification and model and complicated matching work needs to be carried out on the batteries in order to ensure the voltage consistency of the n parallel battery packs.

Disclosure of Invention

In view of this, an object of the present application is to provide an energy storage system to solve a circulating current problem of multiple parallel connection of battery packs in an existing energy storage system.

The technical scheme adopted by the application for solving the technical problems is as follows:

according to one aspect of the application, an energy storage system is provided, which comprises an isolation transformer connected with a power grid, wherein one or more alternating current switch cabinets are further connected with the isolation transformer, one or more DC/AC converters are connected with the alternating current switch cabinets, and one or more battery packs are connected with each DC/AC converter.

In one embodiment, each of the DC/AC converters may be installed in a decentralized manner or may be placed in a centralized manner.

In one embodiment, one or more first switches are disposed within the ac switchgear.

In one embodiment, the number of the first switches is equal to the number of the DC/AC converters, and each of the DC/AC converters is connected to the isolation transformer through one of the first switches.

In one embodiment, the first switch comprises a disconnector or a circuit breaker.

In one embodiment, each of said DC/AC converters has an application range of 20kw-300 kw.

In one embodiment, a second switch is provided between the isolation transformer and the external power grid.

In one embodiment, the second switch comprises a disconnector or a circuit breaker.

In one embodiment, each of the DC/AC converters is a single-pole DC/AC converter or a double-pole DC/AC converter.

The energy storage system of the embodiment of the application is connected with one or more DC/AC converters through the alternating current switch cabinet, and each DC/AC converter is connected with one or more battery packs; the circulation problem generated by the parallel connection of multiple branches of the battery pack is eliminated, the application flexibility of the energy storage system is improved, and the competitiveness of the product is improved.

Drawings

FIG. 1 is a schematic diagram of a prior art energy storage system;

fig. 2 is a schematic diagram of an energy storage system according to an embodiment of the present application.

The implementation, functional features and advantages of the objectives of the present application will be further explained with reference to the accompanying drawings.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer and clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

As shown in fig. 2, the embodiment of the present application provides an energy storage system, which includes an isolation transformer connected to a power grid, and a switch K0 is provided between the isolation transformer and an external power grid, so that the arrangement is safer on one hand, and can also prevent interference on the other hand.

In this embodiment, the switch K0 includes a disconnector or a circuit breaker.

The isolation transformer is further connected with one or more alternating current switch cabinets (shown as K1-Km in the figure), the alternating current switch cabinets are connected with one or more DC/AC converters, and each DC/AC converter is connected with one or more battery packs (shown as 11-1 n and m 1-mn in the figure). Each DC/AC converter can set different parameters according to different configurations of corresponding different battery packs, and is suitable for different battery packs, and preferably, the application range of each DC/AC converter is 20-300 kw. Each of the DC/AC converters may be a single-stage DC/AC converter or a bipolar DC/AC and DC/DC converter.

Each DC/AC converter can be installed in a scattered mode or placed in a concentrated mode, and therefore the flexibility of application of the energy storage system is improved.

Each branch (each DC/AC converter and battery pack is a branch) can select batteries of different types, different models and different SOCs (State of Charge), so that the requirement on battery selection is reduced, the number of parallel circuits on the direct current side is reduced, the initial investment cost is reduced, the circulation current generated by parallel connection of the battery packs is avoided, and the system efficiency is improved.

One or more switches (shown as K11-K1 n and Km 1-Kmn in the figure) are arranged in the alternating current switch cabinet, and the number of the switches is equal to that of the DC/AC converters; each of the DC/AC converters is connected to the isolation transformer through the switch. When a certain branch in the system breaks down, the corresponding switch is switched off, the operation of the whole system is not influenced, and the utilization rate of the equipment is improved.

In the present embodiment, the switches (shown as K11 to K1n, Km1 to Kmn in the figure) include disconnecting switches or circuit breakers.

The preferred embodiments of the present application have been described above with reference to the accompanying drawings, and are not intended to limit the scope of the claims of the application accordingly. Any modifications, equivalents and improvements which may occur to those skilled in the art without departing from the scope and spirit of the present application are intended to be within the scope of the claims of the present application.

Claims

1. An energy storage system is characterized by comprising an isolation transformer connected with a power grid, wherein the isolation transformer is also connected with one or more alternating current switch cabinets, one or more DC/AC converters are connected with the alternating current switch cabinets, and one or more battery packs are connected with each DC/AC converter.

2. The energy storage system of claim 1, wherein each of said DC/AC converters may be installed in a decentralized or centralized manner.

3. The energy storage system of claim 1 or 2, wherein one or more first switches are provided within the ac switchgear.

4. The energy storage system of claim 3, wherein the number of said first switches is equal to the number of said DC/AC converters, each of said DC/AC converters being connected to said isolation transformer through one of said first switches.

5. The energy storage system of claim 3 or 4, wherein the first switch comprises a disconnector or a circuit breaker.

6. Energy storage system according to any of claims 1-5, characterized in that each of said DC/AC converters has an application range of 20-300 kw.

7. The energy storage system of any of claims 1-6, wherein a second switch is provided between the isolation transformer and an external power grid.

8. The energy storage system of claim 7, wherein the second switch comprises a disconnector or a circuit breaker.

9. The energy storage system of any of claims 1-8, wherein each of said DC/AC converters is a single-stage DC/AC converter or a bipolar DC/AC and DC/DC converter.