Energy storage parallel operation system

Abstract

The utility model discloses an energy storage parallel operation system, which at least comprises an electricity meter, a plurality of equipment-level EMS (energy management system) devices connected with the electricity meter through a bus, and an energy storage cabinet connected with each equipment-level EMS device, the electricity meter is used for metering electric energy data of the output end of the transformer and sending the electric energy data to each equipment-level EMS device through a bus; the equipment-level EMS device is used for determining the charging and discharging power of each energy storage cabinet according to the acquired electric energy data and the proportionality coefficient k of each energy storage cabinet and sending the charging and discharging power to the corresponding energy storage cabinet; each energy storage cabinet at least comprises a PCS and a battery pack, the PCS is an energy storage converter, and the output end of each PCS converges and is connected into a power grid and is used for controlling the charging and discharging process of the battery pack and carrying out alternating current and direct current conversion according to the obtained charging and discharging power data. By adopting the technical scheme of the utility model, the charging and discharging states of the corresponding energy storage cabinets can be directly controlled according to load requirements without arranging a station-level EMS (Energy Management System), so that the system architecture is greatly simplified.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage, in particular to an energy storage parallel system. Background Art

[0002] Different application scenarios require different working modes for energy storage systems, such as the peak-valley mode for earning the difference between peak and valley electricity prices, the backup power mode for backup power supply occasions, the command mode for remote control / demand response / grid dispatching / virtual grid, the planning mode for expected working hours, etc. Therefore, each energy storage system needs an EMS (energy management system) to control the operating mode of the energy storage system, and it must also have functions such as equipment monitoring, dispatching control, data forwarding, and power trading.

[0003] Since each industrial and commercial energy storage application scenario is different, the energy storage capacity required is also different. Each manufacturer will make a standard capacity energy storage system. When the application scenario requires a larger capacity / power energy storage, multiple standard capacity energy storage systems are connected in parallel to form a larger capacity system. Figure 1 The figure shows the architecture diagram of a single energy storage cabinet grid-connected system. The EMS sends data to the remote background through wireless communication and receives control and scheduling functions from the background.

[0004] EMS architecture with multiple machines in parallel Figure 2 As shown in the figure, the entire energy storage system consists of multiple energy storage cabinets, junction cabinets and grid cabinets. Each energy storage cabinet consists of a battery pack and a PCS; the junction cabinet consists of a busbar, electrical control components and a device-level EMS; the grid cabinet consists of a busbar, electrical control components and a station-level EMS. The PCS outputs of each energy storage cabinet converge at the junction cabinet and are then controlled by electrical control components; multiple junction cabinets converge at the grid cabinet and are then controlled by electrical control components and connected to the grid after transformer transformation; the station-level EMS measures the load at the output end of the transformer through an electric meter, evenly distributes the charging and discharging power of each energy storage cabinet according to the operation strategy, and sends the operation data to the remote background monitoring system through wireless communication. Each device-level EMS communicates with and is controlled by the station-level EMS through a communication bus, and the station-level EMS controls and coordinates the work of each energy storage cabinet.

[0005] The existing solutions have at least the following disadvantages:

[0006] (1) Large-capacity applications must be equipped with a site-level EMS. Since the device-level EMS can manage a maximum of 5 to 8 energy storage cabinets, when the number of parallel energy storage cabinets exceeds this number, the site-level EMS is required to coordinate the work of each device-level EMS, which processes a large amount of data, has high performance requirements, and has a complex system architecture and high costs.

[0007] (2) The electric meter first sends the electric energy data to the site-level EMS, which then distributes the electric energy data to each device-level EMS, which then controls the charging and discharging power of each energy storage cabinet under it. Multi-level communication has a long delay, and the load data changes in real time, that is, the electric energy data received by each energy storage cabinet may not be the transformer output load at the same time, resulting in mismatched charging and discharging power of each energy storage cabinet. The result of the accumulation of all energy storage cabinets is that the charging and discharging power may be greater than the demand, or less than the demand, which in turn affects the operating benefits of the entire energy storage system.

[0008] (3) When using a single cabinet, the equipment-level EMS is in the energy storage cabinet. When multiple cabinets are connected in parallel, the equipment-level EMS is moved to the junction cabinet. The energy storage cabinets need to be stocked in two types: single use and parallel use, which makes stocking difficult.

[0009] (4) All energy storage cabinets connected in parallel must be standard products, that is, the capacity and power configuration of each energy storage cabinet must be consistent, and the total capacity / power must be an integer multiple of a single cabinet. This is different from the actual needs of the electricity user and affects the benefits.

[0010] Therefore, in view of the defects of the prior art, it is necessary to propose a technical solution to solve the technical problems existing in the prior art. Utility Model Content

[0011] In view of this, it is indeed necessary to provide an energy storage parallel system, in which the electricity meter communicates directly with multiple equipment-level EMS devices through the bus. At the same time, the equipment-level EMS device is configured with standardized parameters and can directly control the charging and discharging status of the corresponding energy storage cabinet according to load demand, thereby eliminating the need to set up a site-level EMS, greatly simplifying the system architecture.

[0012] In order to solve the technical problems existing in the prior art, the technical solution of the utility model is as follows:

[0013] An energy storage parallel system comprises at least an electric meter, a plurality of equipment-level EMS devices connected to the electric meter via a bus, and an energy storage cabinet connected to each equipment-level EMS device, wherein the electric meter is used to measure load data at the output end of a transformer and send the electric energy data to each equipment-level EMS device via a bus; the equipment-level EMS device is used to determine the charge and discharge power of the energy storage cabinet according to the acquired electric energy data and the proportional coefficient k of each energy storage cabinet and send the power to the corresponding energy storage cabinet; each energy storage cabinet comprises at least a PCS and a battery pack, the PCS is an energy storage converter, and each PCS output end is merged into a power grid, and is used to control the charging and discharging process of the battery pack and perform AC / DC conversion according to the acquired charge and discharge power data.

[0014] As a further improvement scheme, a grid-connected cabinet and a combiner cabinet are also provided. The electric meter is provided in the grid-connected cabinet. The grid-connected cabinet is used to combine the outputs of multiple combiner cabinets and then connect to the power grid; the combiner cabinet is used to combine the outputs of multiple energy storage cabinets connected to it.

[0015] As a further improvement plan, each equipment-level EMS device is configured with the following parameters according to actual project requirements: the total rated power P1 of all parallel energy storage cabinets and the rated power P2 of the energy storage cabinet, the proportionality coefficient k=P2 / P1, and the acquired electric energy data multiplied by the proportionality coefficient k is the charging and discharging power of the energy storage cabinet.

[0016] As a further improvement scheme, the equipment-level EMS device is arranged in the junction cabinet, and each equipment-level EMS device is connected to a plurality of energy storage cabinets via a 485 bus or a CAN bus.

[0017] As a further improvement, the electric meter is connected to a plurality of equipment-level EMS devices via a 485 bus or a CAN bus.

[0018] As a further improvement, the charging and discharging power of all parallel energy storage cabinets is equal to the load demand, and the sum of the rated powers of all parallel energy storage cabinets is equal to P1, that is, the cumulative sum of the proportional coefficients k of all energy storage cabinets is equal to 1.

[0019] As a further improvement, energy storage cabinets with the same configuration are connected in parallel. The following parameters are configured in each equipment-level EMS device according to actual project requirements: the total number of parallel units k1 and the number of energy storage cabinets managed by this equipment-level EMS device k2, and the proportional coefficient k=k2 / k1.

[0020] As a further improvement plan, the equipment-level EMS device is set in the energy storage cabinet, and each equipment-level EMS device manages one energy storage cabinet.

[0021] As a further improvement plan, energy storage cabinets with the same configuration are used in parallel, and the following parameters are configured in each equipment-level EMS device according to actual project requirements: total parallel quantity k1, proportional coefficient k=1 / k1.

[0022] As a further improvement, each energy storage cabinet is also provided with a BMS, where the BMS is a battery management system for managing the charging and discharging process of the battery pack.

[0023] Compared with the prior art, the utility model has the following effects and advantages:

[0024] 1. The meter communication bus can be compatible with hundreds of communication nodes (equipment-level EMS devices), which is infinite for industrial and commercial energy storage, thus eliminating the need for site-level EMS and greatly reducing system costs;

[0025] 2. As the EMS device with standardized parameters is configured, each energy storage cabinet works independently without the need to coordinate with other parallel energy storage cabinets, and the system architecture is simple;

[0026] 3. Since the site-level EMS is cancelled and the data is sent directly by the meter at a fixed time, it not only simplifies the network level, but also ensures that the power information obtained by each device-level EMS is at the same time, without time difference, and the charging and discharging power distribution (current sharing) is more reasonable; the input and output power of each energy storage cabinet is determined according to the meter data at the same time, and the total charging and discharging power is equal to the demand, which is neither too large nor too small, thus improving the benefits; BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the grid-connected architecture of a single energy storage cabinet in the prior art.

[0028] Figure 2 This is a schematic diagram of the prior art architecture of connecting multiple energy storage cabinets in parallel and to the grid.

[0029] Figure 3 The utility model is a system architecture block diagram of an energy storage parallel system.

[0030] Figure 4 This is a system architecture block diagram of another preferred implementation of the energy storage parallel system of the utility model.

[0031] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0032] The technical solution provided by the utility model will be further described below in conjunction with the accompanying drawings.

[0033] See also Figure 3 , shown is an architectural block diagram of an energy storage parallel system provided by the utility model, which at least includes an electric meter, a plurality of equipment-level EMS devices connected to the electric meter via a bus, and an energy storage cabinet connected to each equipment-level EMS device.

[0034] In this architecture, the site-level EMS in the grid-connected cabinet of the prior art is eliminated, and the electric meter periodically sends electric energy data to the communication bus. Each device-level EMS listens to this electric energy data information and determines the charging and discharging power in turn. Among them, the electric meter is used to measure the electric energy data at the output end of the transformer and send the electric energy data to each device-level EMS device through the bus; the device-level EMS device is used to determine the charging and discharging power of the energy storage cabinet based on the acquired electric energy data and the proportional coefficient k of each energy storage cabinet and send it to the corresponding energy storage cabinet; each energy storage cabinet includes at least a PCS and a battery pack, and the PCS is an energy storage converter. Each PCS output end is merged into the power grid, which is used to control the charging and discharging process of the battery pack and perform AC / DC conversion according to the acquired charging and discharging power data. Furthermore, each energy storage cabinet is also provided with a BMS, which is a battery management system for managing the charging and discharging process of the battery pack.

[0035] In the above technical solution, the meter communication bus can be compatible with hundreds of communication nodes (equipment-level EMS devices), which is infinite for industrial and commercial energy storage, so there is no need for site-level EMS, which greatly reduces the system cost; at the same time, due to the configuration of standardized parameter equipment-level EMS devices, each energy storage cabinet works independently, without the need to coordinate with other parallel energy storage cabinets, and the system architecture is simple; due to the simplification of the network level, it is ensured that the power information obtained by each equipment-level EMS is at the same time, without time difference, and the charging and discharging power distribution (current sharing) is more reasonable; the input and output power of each energy storage cabinet is based on the meter data at the same time, and the total charging and discharging power is equal to the demand, which is neither too large nor too small, thereby increasing the benefits. When the number of parallel machines is relatively small, such as 2~3, even the junction cabinet is not needed, and the cost is low.

[0036] Figure 3 In the shown architecture, a grid-connected cabinet and a combiner cabinet are also provided. The electric meter can be provided in the grid-connected cabinet. The grid-connected cabinet is used to combine the outputs of multiple combiner cabinets and then connect to the power grid; the combiner cabinet is used to combine the outputs of multiple energy storage cabinets connected to it and then connect to the grid-connected cabinet.

[0037] In a preferred embodiment, the following parameters are configured in each equipment-level EMS device according to actual project requirements: the total rated power P1 of all parallel energy storage cabinets and the rated power P2 of the energy storage cabinet, the proportionality coefficient k=P2 / P1, and the acquired electric energy data multiplied by the proportionality coefficient k is the charging and discharging power of the energy storage cabinet.

[0038] That is, the equipment-level EMS device sets two configurable parameters, the total rated power P1 of all parallel energy storage cabinets and the rated power P2 of the energy storage cabinet. These two parameters are configured according to the actual application project. After receiving the power data sent by the meter, the equipment-level EMS multiplies the power data by the proportional coefficient k=P2 / P1, and then uses this proportionally adjusted power data as the load data output by the transformer. The PCS of each energy storage cabinet works independently based on this load data, and there is no need to coordinate with each other.

[0039] The above technical solution uses two configurable parameter ratios to adjust the transformer load data received by the device-level EMS to achieve reasonable allocation of charging and discharging power for each energy storage cabinet. At the same time, the two parameters of rated power and total rated power are used to achieve parallel use of energy storage cabinets with different capacity / power configurations.

[0040] Furthermore, the sum of the rated powers of all parallel energy storage cabinets is equal to P1, that is, the sum of the proportional coefficients kn of all energy storage cabinets is equal to 1. The discharge power of the parallel energy storage cabinet system needs to be equal to the load demand.

[0041] Preferably, the equipment-level EMS device is arranged in the junction cabinet, and each equipment-level EMS device is connected to a plurality of energy storage cabinets via a 485 bus or a CAN bus.

[0042] Preferably, the electric meter is connected to multiple equipment-level EMS devices via a 485 bus or a CAN bus.

[0043] The technical solution of the utility model can be used in parallel with energy storage cabinets of different capacities and powers, which can more accurately adapt to the load requirements of the power user and improve the rate of return. In another preferred embodiment, energy storage cabinets with the same configuration are used in parallel, and each equipment-level EMS device is configured with the following parameters according to the actual project requirements: the total number of parallel units k1 and the number of energy storage cabinets managed by the equipment-level EMS device k2, and the proportional coefficient k=k2 / k1.

[0044] See also Figure 4 , shown is a system architecture diagram of another implementation mode of the utility model, in which the equipment-level EMS device is arranged in the energy storage cabinet, and each equipment-level EMS device manages one energy storage cabinet, thereby being able to unify specifications and facilitate stocking.

[0045] As a further improvement plan, energy storage cabinets with the same configuration are used in parallel, and the following parameters are configured in each equipment-level EMS device according to actual project requirements: total parallel quantity k1, proportional coefficient k=1 / k1.

[0046] The utility model also discloses an equipment-level EMS device, which is directly connected to an electric meter, for acquiring electric energy data and determining the charging and discharging power of the energy storage cabinet according to the acquired electric energy data and a proportional coefficient k of each energy storage cabinet, and sending the power to the corresponding energy storage cabinet.

[0047] In a preferred embodiment, the following parameters are configured in each equipment-level EMS device according to actual project requirements: the total rated power P1 of all parallel energy storage cabinets and the rated power P2 of the energy storage cabinet, the proportionality coefficient k=P2 / P1, and the acquired electric energy data multiplied by the proportionality coefficient k is the charging and discharging power of the energy storage cabinet.

[0048] The above embodiments are only used to help understand the method and core idea of ​​the utility model. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made to the utility model without departing from the principle of the utility model, and these improvements and modifications also fall within the scope of protection of the claims of the utility model.

[0049] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An energy storage parallel system, characterized in that: At least includes an electric meter, a plurality of equipment-level EMS devices connected to the electric meter through a bus, and an energy storage cabinet connected to each equipment-level EMS device, wherein the electric meter is used to measure the electric energy data at the output end of the transformer and send the electric energy data to each equipment-level EMS device through the bus; the equipment-level EMS device is used to determine the charge and discharge power of the energy storage cabinet according to the acquired electric energy data and the proportional coefficient k of each energy storage cabinet and send it to the corresponding energy storage cabinet; each energy storage cabinet includes at least a PCS and a battery pack, the PCS is an energy storage converter, and each PCS output end is merged into the power grid, and is used to control the charging and discharging process of the battery pack and perform AC / DC conversion according to the acquired charge and discharge power data; A grid-connected cabinet and a combiner cabinet are also provided. The electric meter is provided in the grid-connected cabinet. The grid-connected cabinet is used to combine the outputs of multiple combiner cabinets and then connect to the power grid; the combiner cabinet is used to combine the outputs of multiple energy storage cabinets connected thereto.

2. The energy storage parallel system according to claim 1, characterized in that: The equipment-level EMS device is arranged in the combiner cabinet, and each equipment-level EMS device is connected to a plurality of energy storage cabinets via a 485 bus or a CAN bus.

3. The energy storage parallel system according to claim 1, characterized in that: The electric meter is connected to a plurality of equipment-level EMS devices via a 485 bus or a CAN bus.

4. The energy storage parallel system according to claim 1, characterized in that: The equipment-level EMS device is installed in the energy storage cabinet, and each equipment-level EMS device manages one energy storage cabinet.

5. The energy storage parallel system according to claim 1, characterized in that: Each energy storage cabinet is also provided with a BMS, which is a battery management system for managing the charging and discharging process of the battery pack.

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