Dyness Knowledge | C&I energy storage 3S system sharing

Awareness of climate change and the harmful effects of traditional energy sources such as coal and oil is growing. At the same time, renewable energy sources are becoming more attractive to investors and consumers as their costs decrease and their efficiency gradually increases. As a result, global demand for renewable energy has been growing steadily. Renewable energy currently accounts for approximately 28% of global electricity generation, including sources such as hydropower, wind, solar and biomass. It is expected that by 2028, China's newly installed renewable energy capacity will account for nearly 60% of the world's new installed renewable energy capacity.

Another problem that needs to be overcome to popularize renewable energy is the sustainability of power generation. Common renewable energy sources are solar energy and wind energy. Their power generation capacity is limited by natural weather conditions, and the waveformity of power generation is large. Therefore, energy storage has become an essential part of renewable energy, which can store energy during idle periods. It is released during peak energy demand periods to improve the stability and reliability of the power system, ultimately reducing energy costs and carbon emissions.、

Against this background, efficient energy storage technology and safe and economical energy storage products are developing rapidly. A complete electrochemical energy storage system mainly consists of a battery pack, battery management system (BMS), energy management system (EMS), energy storage converter (PCS) and other electrical equipment.

Today we will talk about the 3S modules that everyone often hears about in energy storage systems: BMS, EMS, and PCS.

Battery management system BMS: plays a sensing role and is mainly responsible for battery monitoring, evaluation, protection and balancing. Energy management system EMS: plays a decision-making role and is mainly responsible for data collection, network monitoring and energy scheduling. Energy storage converter PCS: plays an executive role, and its main function is to control the charging and discharging process of the energy storage battery pack and perform AC to DC conversion.

BMS

(Battery Management System), BMS battery system is commonly known as battery nanny or battery manager. It is a device that monitors the status of energy storage batteries. The cells together form a battery system.

• BMS measures the basic parameters of the battery, including voltage, current, temperature, etc., to prevent overcharge and overdischarge of the battery and extend the service life of the battery.
• BMS needs to calculate and analyze the SOC (battery remaining capacity) and SOH (battery health status) of the battery, and report abnormal information in a timely manner.

Most BMS systems have a three-layer architecture, and the hardware is mainly divided into slave control units, master control units and master control units.

• Bottom layer: Slave control BMU, which is the single battery management layer. It is composed of a battery monitoring chip and its auxiliary circuits. It is responsible for collecting various information of a single battery, calculating and analyzing the SOC (battery remaining capacity) and SOH (battery health status) of the battery, achieving active balancing of the single battery, and balancing the single battery. Body abnormality information is uploaded to the main control.
• Middle layer: Main control BCU, which is the battery pack management layer. Collect various single battery information uploaded by BMU and collect battery pack information. Calculate and analyze the SOC and SOH of the battery pack.
• Upper layer: master control, which is the battery cluster management layer. Responsible for the overall coordination within the system and external information interaction with EMS and PCS, and controlling the operation process of the entire BMS system according to external requests.

EMS

(Energy Management System), also known as energy management system, is an extremely important core component of the entire energy storage system.

On the one hand, it is directly responsible for the control strategy of the energy storage system, and the control strategy affects the decay rate and cycle life of the batteries in the system, thereby determining the economics of energy storage. On the other hand, it also monitors fault anomalies during system operation, playing an important role in promptly and quickly protecting equipment and ensuring safety.

The EMS energy management system is generally divided into equipment layer, communication layer and application layer.

• Equipment layer: Energy harvesting transformation (PCS, BMS) is required for support.
• Communication layer: mainly includes links, protocols, transmission, etc.
• Information layer: Mainly includes caching middleware, database, and server. The database system is responsible for data processing and data storage, recording real-time data and important historical data, and providing historical information query.
• Application layer: Expression forms include APP, Web, etc., providing managers with a visual monitoring and operation interface. Specific functions include energy conversion decision-making, energy data transmission and collection, real-time monitoring and control, operation and maintenance management analysis, and power/electricity visualization. analysis, remote real-time control, etc.

The main functions of EMS:

• System overview: Displays the operation overview of the current energy storage system, including: energy storage charge and discharge capacity, real-time power, SOC, revenue, energy diagram, multi-power operation diagram, etc., as the main page for monitoring.
• Equipment monitoring: View various types of equipment by equipment, including but not limited to PCS, BMS, air conditioners, electricity meters, smart circuit breakers, fire hosts, various sensors, etc., and support equipment control.
• Operation income: Displaying energy storage income and power information is the function that owners are most concerned about.
• Fault alarms: Summarize fault alarms of various types of equipment and query them by time, status, level, etc.
• Statistical analysis: Query the historical operating data and related reports of the device, and support data export.
• Energy management: The core function of EMS, configuring energy storage strategies, including manual and automatic modes, to meet the needs of debugging, inspection, daily operation, maintenance and other scenarios.

PCS

Energy storage converter PCS, also known as bidirectional energy storage inverter, is the core component that realizes the two-way flow of electric energy between the energy storage system and the power grid. It is used to control the charging and discharging process of the battery and perform AC and DC conversion.

PCS composition and characteristics: PCS is composed of IGBT (insulated gate bipolar transistor), PCB board (printed circuit board), wires and cables and other hardware. Its main functions include power stabilization, information exchange, protection, etc. PCS determines the output power quality and dynamic characteristics, and also greatly affects the service life of the battery.

PCS application scenarios:

• The power of the PCS of the energy storage power station is generally greater than 10MW. It adopts a cascaded multi-level topology and adopts IGBT module design. Generally, N AC converters are installed inside the container to support parallel operation of multiple machines. A transformer is required to boost the voltage and connect to the power grid.
• The power of centralized PCS is above 250KW. Currently, it mostly adopts two-level topology. It also adopts IGBT modular design and uses fewer power devices. The power of a single machine can reach MW level, which requires high system reliability.
• The power of industrial and commercial PCS is generally below 250KW. Currently, three-level topology is mostly used. Combined with distributed photovoltaics, it can realize self-use and profit from the peak and valley price difference of the power grid.
• The power of household PCS is below 10KW. It is combined with household photovoltaic and used as emergency power supply, electricity bill management, etc., and has higher requirements on safety regulations and noise. As the scale of the energy storage market continues to expand, energy storage system PCS equipment is no longer a simple conversion device, but requires higher integration capabilities. In the future, energy storage system PCS will increasingly tend to integrate equipment. Through software development, upgrades, and optimization, intelligent control and safety performance guarantee of the energy storage system will be realized, thereby achieving better application of energy storage technology in the power grid.

Generally speaking, in the energy storage system, the battery pack feeds back status information to the battery management system BMS. The BMS shares it with the energy management system EMS and the energy storage converter PCS; the EMS sends the control information to the PCS and BMS based on optimization and scheduling decisions, and controls the single battery/battery group to complete charging and discharging, etc. The 3S communicate with each other and collect information feedback status from each other to ensure that the entire energy storage system operates efficiently, accurately and safely in accordance with the formulated strategy.

Dyness DH200Y product combines BMS and EMS into one, eliminating the communication process between BMS and EMS. The execution strategy is more efficient, the execution results are more accurate, and communication failures are completely avoided.

Driven by the country's vigorous promotion of friendly policies to achieve the goal of "carbon peaking and carbon neutrality" and the vigorous development of the industrial chain, the large-scale energy storage market has quietly arrived.

As the market scale expands, the energy storage field is becoming increasingly diversified. Home energy storage, large-scale power energy storage, industrial and commercial energy storage and other fields have their own characteristics and can complement each other. Therefore, the prospects for new energy storage construction are very broad, and electrochemical energy storage is one of the fastest growing and most stable fields, and is expected to be more widely used and promoted in the future.

Author：Shuyu Zhang

Dyness Digital Energy Technology Co., LTD

WhatsApp: +86 181 3643 0896??? Email: [email protected]

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