阅读说明：本技术 一种通用接口、控制方法及储能系统 (Universal interface, control method and energy storage system ) 是由 彭文鑫 郑可 侯兴哲 李松浓 于 2020-05-07 设计创作，主要内容包括：本发明公开了一种通用接口、控制方法及储能系统,所述通用接口包括,双向DC/DC变换器连接于储能单元和所述滤波器之间；DC/AC逆变器包括连接至所述滤波器的DC端,以及作为交流或直流电源接入口的AC端；控制信号单元用于改变双向DC/DC变换器和DC/AC逆变器的工作状态以适配于对应的交流或直流电压类型及工作模式。本发明方案通过双向DC/DC变换器、滤波器和DC/AC逆变器组成通用接口,通过控制信号单元对接口进行控制,实现了储能系统接口对于交流直流的兼容,扩展了储能的应用范围。(The invention discloses a general interface, a control method and an energy storage system, wherein the general interface comprises a bidirectional DC/DC converter connected between an energy storage unit and a filter; the DC/AC inverter comprises a DC end connected to the filter and an AC end used as an alternating current or direct current power supply inlet; the control signal unit is used for changing the working states of the bidirectional DC/DC converter and the DC/AC inverter to be adapted to the corresponding alternating current or direct current voltage type and working mode. According to the scheme of the invention, the bidirectional DC/DC converter, the filter and the DC/AC inverter form a universal interface, and the interface is controlled by the control signal unit, so that the compatibility of the interface of the energy storage system for alternating current and direct current is realized, and the application range of energy storage is expanded.)

1. A general interface is used for AC/DC energy storage and is characterized by comprising a bidirectional DC/DC converter, a filter, a DC/AC inverter and a control signal unit;

the bidirectional DC/DC converter is connected between the energy storage unit and the filter;

the DC/AC inverter comprises a DC end connected to the filter and an AC end used as an alternating current or direct current power supply inlet;

the control signal unit is used for changing the working states of the bidirectional DC/DC converter and the DC/AC inverter to be adapted to the corresponding alternating current or direct current voltage type and working mode.

2. The universal interface of claim 1, wherein the bidirectional DC/DC converter comprises two Buck-Boost DC converters in anti-parallel.

3. The universal interface of claim 1, wherein the DC/AC inverter is a full bridge inverter.

4. The universal interface of claim 1 wherein a filter circuit is disposed between the bidirectional DC/DC converter and the energy storage unit and between the DC/AC inverter and an AC or DC power source.

5. The universal interface of claim 1, wherein the operating mode of the energy storage unit comprises a charging mode, and the control signal unit is specifically configured to, after determining that the energy storage unit enters the charging mode:

switching the bidirectional DC/DC converter to a charging loop and regulating the DC/AC inverter to a rectification mode;

the charging current is adjusted by controlling the duty ratio of a switching signal of the bidirectional DC/DC converter charging loop.

6. The universal interface of claim 1, wherein a power source accessed by the universal interface is a direct current power source, the operating mode of the energy storage unit includes a discharge mode, and the control signal unit is specifically configured to:

switching the bidirectional DC/DC converter to a discharge loop and adjusting the DC/AC inverter to a DC output mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

7. The universal interface of claim 1, wherein a power source connected to the universal interface is an ac power source, the operating mode of the energy storage unit includes a discharge mode, and the control signal unit is specifically configured to:

switching the bidirectional DC/DC converter to a discharge loop, and adjusting the DC/AC inverter to an inversion mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

8. The universal interface of claim 7, wherein said control signal unit is further configured to:

the DC/AC inverter is controlled to work in an inversion mode through the PWM signal, and the PWM control signal adopts reference current hysteresis control.

9. A method for controlling a universal interface according to any one of claims 1 to 8, for ac/dc energy storage, comprising the steps of:

determining the voltage type of a power supply accessed by the universal interface and the working mode of the energy storage unit;

the operating states of the bidirectional DC/DC converter and the DC/AC inverter are changed by the control signals to adapt to the corresponding voltage type and operating mode.

10. The control method according to claim 9, wherein the operation mode of the energy storage unit comprises a charging mode, and the changing of the operation state and the operation mode of the bidirectional DC/DC converter and the DC/AC inverter by the control signal comprises:

after the energy storage unit is determined to enter a charging mode, the bidirectional DC/DC converter is switched to a charging loop, and the DC/AC inverter is adjusted to a rectifying mode;

the charging current is adjusted by controlling the duty ratio of a switching signal of the bidirectional DC/DC converter charging loop.

11. The control method according to claim 9 or 10, wherein the power source accessed by the universal interface is a direct current power source, the operation mode of the energy storage unit includes a discharge mode, and the changing the operation state of the bidirectional DC/DC converter and the DC/AC inverter by the control signal includes:

after the energy storage unit is determined to enter a discharging mode, the bidirectional DC/DC converter is switched to a discharging loop, and the DC/AC inverter is adjusted to a direct current output mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

12. The control method according to claim 9 or 10, wherein the power source connected to the universal interface is an alternating current power source, the operation mode of the energy storage unit includes a discharge mode, and the operation state of the bidirectional DC/DC converter and the DC/AC inverter is changed by a control signal, including:

after the energy storage unit is determined to enter a discharge mode, the bidirectional DC/DC converter is switched to a discharge loop, and the DC/AC inverter is adjusted to an inversion mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

13. The control method of claim 12, wherein said adjusting the DC/AC inverter to the inversion mode comprises:

the DC/AC inverter is controlled to work in an inversion mode through the PWM signal, and the PWM control signal adopts reference current hysteresis control.

14. An energy storage system, characterized in that the system comprises energy storage units arranged in a distributed manner and a universal interface according to any of claims 1-8.

Technical Field

The invention relates to the technical field of energy storage, in particular to a universal interface, a control method and an energy storage system.

Background

The application scenarios of the existing energy storage system mainly include:

1. and auxiliary power supply of the distributed power supply, such as unstable power supplies of photovoltaic power, wind power and the like.

2. The standby energy source for the dispatching operation of the power grid can be used for emergency power supply, peak load shifting and valley load filling of the power demand side and the like.

3. DC micro-grid energy storage and power supply

4. Provided is an electric automobile.

The different application scenarios use different grid-connected, current-converting and control technologies for the energy storage system, and the application range of the energy storage system is limited. The energy storage of the distributed power supply is mainly connected with a direct current side, and the distributed power supply is required to have the functions of charging and storing energy by the distributed power supply, charging and storing energy by a power grid, supplying energy to a local load, having the power grid function and the like; the energy storage of alternating current measurement mainly needs to have the capacity of being connected with a large power grid; and the direct current micro-grid only needs to have the functions of storing and supplying energy to the direct current side.

Modern power grids begin to develop towards intelligent digitization, and the increase of the access amount of new energy makes the operation management technology of the traditional power grids face challenges, and meanwhile, new technical requirements are put forward on infrastructure and hardware equipment. A dynamic regulation and control technology based on source, network, load and storage cooperative interaction requires that each unit accessed to a power grid has the characteristics of quick perception and flexible regulation and control. Currently, the same energy storage device can only work in a direct current network or an alternating current network, so that the use scene of the energy storage device is limited.

Disclosure of Invention

In view of the foregoing defects in the prior art, an object of the present invention is to provide a universal interface, a control method, and an energy storage system, which are used to solve the technical problems that in the prior art, an interface of an energy storage system is not universal and cannot be flexibly configured.

One of the objectives of the present invention is achieved by such a technical solution, which is a universal interface for AC/DC energy storage, comprising a bidirectional DC/DC converter, a filter, a DC/AC inverter, and a control signal unit;

the bidirectional DC/DC converter is connected between the energy storage unit and the filter;

the DC/AC inverter comprises a DC end connected to the filter and an AC end used as an alternating current or direct current power supply inlet;

the control signal unit is used for changing the working states of the bidirectional DC/DC converter and the DC/AC inverter to be adapted to the corresponding alternating current or direct current voltage type and working mode.

Optionally, the bidirectional DC/DC converter includes two Buck-Boost direct-current converters connected in parallel in an opposite direction.

Optionally, the DC/AC inverter is a full bridge inverter.

Optionally, a filter circuit is disposed between the bidirectional DC/DC converter and the energy storage unit, and between the DC/AC inverter and the AC or DC power supply.

Optionally, the working mode of the energy storage unit includes a charging mode, and after the energy storage unit is determined to enter the charging mode, the control signal unit is specifically configured to:

switching the bidirectional DC/DC converter to a charging loop and regulating the DC/AC inverter to a rectification mode;

the charging current is adjusted by controlling the duty ratio of a switching signal of the bidirectional DC/DC converter charging loop.

Optionally, the power supply accessed by the universal interface is a direct-current power supply, the working mode of the energy storage unit includes a discharge mode, and after the energy storage unit is determined to enter the discharge mode, the control signal unit is specifically configured to:

switching the bidirectional DC/DC converter to a discharge loop and adjusting the DC/AC inverter to a DC output mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

Optionally, the power supply accessed by the universal interface is an alternating current power supply, the working mode of the energy storage unit includes a discharge mode, and after the energy storage unit is determined to enter the discharge mode, the control signal unit is specifically configured to:

switching the bidirectional DC/DC converter to a discharge loop, and adjusting the DC/AC inverter to an inversion mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

Optionally, the control signal unit is further configured to:

the DC/AC inverter is controlled to work in an inversion mode through the PWM signal, and the PWM control signal adopts reference current hysteresis control.

The second purpose of the invention is realized by the technical scheme, the control method of the universal interface is used for alternating current and direct current energy storage, and comprises the following steps:

determining the voltage type of a power supply accessed by the universal interface and the working mode of the energy storage unit;

the operating states of the bidirectional DC/DC converter and the DC/AC inverter are changed by the control signals to adapt to the corresponding voltage type and operating mode.

Optionally, the working modes of the energy storage unit include a charging mode, and the changing of the working states and working modes of the bidirectional DC/DC converter and the DC/AC inverter by the control signal includes:

after the energy storage unit is determined to enter a charging mode, the bidirectional DC/DC converter is switched to a charging loop, and the DC/AC inverter is adjusted to a rectifying mode;

the charging current is adjusted by controlling the duty ratio of a switching signal of the bidirectional DC/DC converter charging loop.

Optionally, the power source accessed by the universal interface is a direct current power source, the working mode of the energy storage unit includes a discharging mode, and the changing of the working states of the bidirectional DC/DC converter and the DC/AC inverter by the control signal includes:

after the energy storage unit is determined to enter a discharging mode, the bidirectional DC/DC converter is switched to a discharging loop, and the DC/AC inverter is adjusted to a direct current output mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

Optionally, the power source accessed by the universal interface is an alternating current power source, the working mode of the energy storage unit includes a discharge mode, and the working states of the bidirectional DC/DC converter and the DC/AC inverter are changed by the control signal, including:

after the energy storage unit is determined to enter a discharge mode, the bidirectional DC/DC converter is switched to a discharge loop, and the DC/AC inverter is adjusted to an inversion mode;

and the duty ratio of a switching signal of the charging loop of the bidirectional DC/DC converter is controlled to regulate the magnitude of the discharging current.

Optionally, the adjusting the DC/AC inverter to the inversion mode includes:

the DC/AC inverter is controlled to work in an inversion mode through the PWM signal, and the PWM control signal adopts reference current hysteresis control.

The third object of the present invention is achieved by a technical solution, which is an energy storage system, comprising distributed energy storage units and a universal interface as described above.

Due to the adoption of the technical scheme, the invention has the following advantages: according to the scheme of the invention, the bidirectional DC/DC converter, the filter and the DC/AC inverter form a universal interface, and the interface is controlled by the control signal unit, so that the compatibility of the interface of the energy storage system for alternating current and direct current is realized, the application range of energy storage is expanded, the unified production of energy storage devices is facilitated, and positive technical effects are achieved.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

Detailed Description

The invention is further illustrated by the following figures and examples.