Energy storage system, energy storage device and control method of energy storage system

Abstract

The invention relates to an electric energy storage technology, and discloses an energy storage system, an energy storage device and a control method of the energy storage system, and the energy storage system comprises a battery module, an energy storage converter, a power detection unit and an energy management system. The battery module comprises a battery management system and a battery cluster; the energy storage converter is configured to operate in a virtual synchronous machine mode; the power detection unit is used for collecting power data of the load; the energy management system communicates with the energy storage converter, the power detection unit, the battery management system and the power generation unit, and is configured to obtain the real-time operation power of the power generation unit. When the power data of the load is lower than a lower limit value of a preset power operation interval of the power generation unit, the energy storage converter is controlled to enter a charging state so as to increase the output load of the power generation unit; the actual output power of the power generation unit is maintained in the preset power operation interval, and the system operation efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of energy storage system technology, and in particular to an energy storage system, an energy storage device, and a control method for the energy storage system. Background Technology

[0002] In scenarios such as construction machinery operations and drilling platforms, load power fluctuations are significant, especially during processes like lifting drill pipes and starting high-power equipment, which can cause instantaneous spikes in "peak load," while the load power remains relatively stable under normal operating conditions. Currently, power supply for these scenarios mainly relies on generator sets such as diesel generators. To cope with short-term peak load demands, generator sets with sufficient power redundancy need to be configured for long-term online operation.

[0003] Existing power supply solutions exhibit a clear performance-cost trade-off: On the one hand, high-power generators configured to cover peak loads operate at low loads under most normal conditions, resulting in an inefficient "overpowered" operation that increases fuel consumption and reduces power generation efficiency. On the other hand, when generators operate under unsteady conditions with frequent load fluctuations, their response speed struggles to match load changes, easily causing voltage and frequency fluctuations that affect the safe operation of electric drive equipment. This also exacerbates mechanical wear, increases maintenance frequency and downtime risks, and drives up overall operation and maintenance costs. Furthermore, traditional solutions lack flexible power buffering and regulation mechanisms, failing to achieve synergy between efficient generator operation and stable power supply to peak loads.

[0004] To alleviate these issues, the industry has attempted to improve the situation by optimizing power generation unit control strategies or adding redundancy configurations. However, this has not yet resolved the contradiction between load fluctuations and efficient operation of power generation units, and there is still room for improvement in response speed, power regulation accuracy, and overall cost control. Therefore, a power supply solution that can quickly respond to load fluctuations and flexibly adjust power distribution is needed to ensure stable power supply to peak loads while keeping power generation units operating within their efficient range, thus achieving simultaneous optimization of power supply reliability and economy. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides an energy storage system, an energy storage device, and a control method for the energy storage system.

[0006] Firstly, the energy storage system provided in this application adopts the following technical solution: An energy storage system is suitable for parallel connection with an AC busbar to supply power to a load, comprising a battery module, an energy storage converter, a power detection unit, and an energy management system. The battery module includes a battery management system and a battery cluster. The DC side of the energy storage converter is connected to the battery cluster, and the AC side is connected to the AC busbar, configured to operate in a virtual synchronous machine mode. The power detection unit is located at the input end of the AC busbar or the load and is used to collect the power data of the load. The energy management system is communicatively connected to the energy storage converter, the power detection unit, the battery management system, and the power generation unit. The energy management system is configured to acquire the real-time operating power of the power generation unit and execute a power allocation strategy based on the load power data fed back by the power detection unit: when the load power data is lower than the lower limit of the preset power operating range of the power generation unit, the energy management system controls the energy storage converter to enter a charging state, absorbing electrical energy from the AC busbar to increase the output load of the power generation unit, so that the actual output power of the power generation unit is maintained within the preset power operating range.

[0007] By adopting the above technical solutions, the energy storage system and the power generation unit work in parallel and collaboratively. With the help of the virtual synchronous machine mode and power distribution strategy, when the load power is lower than the power operation range of the power generation unit, the energy storage converter absorbs the excess power, preventing the power generation unit from falling into a low-load and inefficient state of "overpowered" operation. At the same time, it stabilizes the power quality, reduces the wear and tear of the power generation unit, and lowers the operation and maintenance costs and energy consumption.

[0008] Optionally, the energy storage converter is configured to employ a droop control strategy: by monitoring the voltage amplitude and frequency of the AC bus, the active and reactive power outputs of the energy storage converter are automatically adjusted using a preset droop coefficient to respond to load power fluctuations.

[0009] By adopting the above technical solution, the droop control strategy enables the energy storage converter to quickly follow the power fluctuations of the load and automatically adjust itself without the need for real-time commands from the energy management system. This achieves millisecond-level response, suppresses voltage and frequency fluctuations caused by sudden load changes, and ensures power supply stability.

[0010] Optionally, the energy management system is also configured to perform the following control: when the total power of the load exceeds the upper limit of the preset power operating range of the power generation unit, the energy management system controls the energy storage converter to enter the discharge state and take over the load power exceeding the upper limit.

[0011] By adopting the above technical solutions, for peak loads in scenarios such as lifting drill pipes and starting high-power machines, the energy storage converter can quickly discharge to supplement the power gap, eliminating the need for too many power generation units to be online for a long time. This satisfies peak power supply demand while maintaining the operation of power generation units within the power range, thus reducing equipment investment costs.

[0012] Optionally, the energy management system is also configured to perform dynamic parameter adjustments: acquire the state of charge of the battery module in real time, and dynamically correct the droop curve parameters of the energy storage converter in virtual synchronous machine mode based on the state of charge value, so as to change the response sensitivity of the energy storage converter to changes in voltage amplitude or frequency.

[0013] By adopting the above technical solution, the droop curve parameters are dynamically adjusted according to the battery state of charge to prevent overcharging or over-discharging of the battery. At the same time, the response characteristics of the energy storage converter are optimized, and the power can be accurately distributed under different battery states, thereby improving the safety and reliability of system operation.

[0014] Optionally, the preset power operating range is set to 70% to 90% of the rated power of the power generation unit.

[0015] By adopting the above technical solutions, the high-efficiency operating range of the matching power generation unit (such as a diesel generator set) in this range can be minimized, fuel consumption can be reduced, unit wear can be reduced, power generation efficiency and equipment service life can be balanced, and overall operation and maintenance costs can be further reduced.

[0016] Secondly, the energy storage device provided in this application adopts the following technical solution: An energy storage device includes a housing and an energy storage system as described in any of the first aspects disposed within the housing.

[0017] By adopting the above technical solutions, the energy storage system is integrated into the enclosure, realizing a modular design. It eliminates the need for complex on-site installation and can be quickly deployed to temporary or mobile scenarios such as engineering machinery operations and drilling platforms. At the same time, it facilitates transportation and maintenance, improving the equipment's scenario adaptability and ease of use.

[0018] Thirdly, the control method for an energy storage system provided in this application adopts the following technical solution: A control method for an energy storage system includes the following steps: S1. Establish data interaction between the energy management system and the external power generation unit controller to obtain the real-time electrical parameters of the power generation unit; S2. Control the energy storage converter to operate in virtual synchronous machine mode, follow load fluctuations based on voltage-frequency droop characteristics, and monitor the total power of the load in real time; compare the total power of the load with the preset power operating range of the power generation unit; when the total power of the load is detected to be lower than the lower limit of the preset power operating range, generate a charging command and send it to the energy storage converter to control the battery cluster to charge in order to increase the load rate and keep the power generation unit within the preset power operating range; and / or, when the total power of the load is detected to be higher than the upper limit of the preset power operating range, generate a discharging command to compensate for the load power gap.

[0019] By adopting the above technical solution, a closed-loop control logic of "data interaction - mode control - power monitoring - command execution" is constructed to ensure that the power generation unit operates within the preset power range and responds quickly to load fluctuations. This improves the problem of low operating efficiency and poor fuel economy caused by the "overpowered" power generation unit due to low load rate in traditional solutions. When the load power is higher than the power operating range of the power generation unit, the energy storage converter releases electrical energy to provide instantaneous power support, preventing the power generation unit from shutting down or undergoing derating protection due to overload, and ensuring the continuity of power supply.

[0020] Optionally, in step S2, during the process of controlling the battery cluster to charge, the change trend of the state of charge of the battery cluster is calculated in real time. When the state of charge reaches the preset overcharge prevention threshold, the energy management system sends a speed regulation command to the controller of the power generation unit to reduce the mechanical power output of the power generation unit.

[0021] By adopting the above technical solution, and combining the battery state of charge with the output regulation of the power generation unit, a dual protection is formed, which not only prevents the battery from being damaged by overcharging, but also ensures that the output of the power generation unit is accurately matched with the load demand, thus maintaining the long-term stable operation of the system.

[0022] Optionally, the control method for the energy storage system may also include the following steps: S3. Perform two-stage regulation control to address step changes in load power: When a step change in load power is detected, the energy storage converter first automatically adjusts its output power based on its droop characteristics to complete the first adjustment. Then, the energy management system recalculates and issues the power setpoint for the energy storage converter based on the total power data of the changed load to complete the second adjustment, locking the output power of the power generation unit back into the preset power operating range.

[0023] By adopting the above technical solutions, the first-level regulation achieves millisecond-level rapid response and suppresses instantaneous power fluctuations; the second-level regulation achieves precise power locking and ensures that the power generation unit remains stable within the power range for a long time. The combination of the two measures balances response speed and regulation accuracy, improving the system's ability to cope with complex load changes.

[0024] Optionally, the control method for the energy storage system may also include the following steps: S4. Perform thermal runaway protection and electrical isolation: The energy management system monitors fire alarm signals or extreme temperature values ​​of the battery clusters; when a thermal runaway alarm signal is received, the energy management system executes a two-way blocking strategy: On the DC side, the pulse output of the energy storage converter is blocked and the DC circuit breaker of the battery cluster is opened to cut off the DC arc. On the AC side, an isolation command is sent to the power generation unit via the communication interface to control the power generation unit to disconnect from the AC bus.

[0025] By adopting the above technical solution, bidirectional electrical blocking is implemented to address the risk of battery thermal runaway, quickly cutting off energy transmission between the DC and AC sides, preventing the fault from escalating, ensuring equipment and personal safety, and improving the system's safety protection level.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. Achieve efficient collaboration between the power generation unit and the energy storage system, stabilize the power generation unit in the power range of 70%-90% of its rated power, improve the problem of "overpowered power supply", reduce energy consumption, reduce equipment wear and tear and operation and maintenance costs; 2. It has millisecond-level peak load response capability. Through virtual synchronous machine mode and droop control strategy, it can quickly respond to load changes, stabilize power quality, and ensure the safe operation of critical electric drive equipment. 3. The modular design and closed-loop control logic combine deployment flexibility and operational reliability, adapting to the needs of various scenarios such as engineering machinery and drilling platforms. At the same time, through thermal runaway protection and dynamic parameter adjustment, the system's safety performance and adaptability are improved. Attached Figure Description

[0027] Figure 1 This is a system block diagram of the energy storage system provided in the embodiments of this application; Figure 2 These are droop characteristic curves provided in the embodiments of this application, where 2(a) is the active power-frequency curve and 2(b) is the reactive power-voltage curve. Figure 3 This is a system structure diagram of the energy storage system provided in the embodiments of this application; Figure 4 This is a topology diagram of the energy storage system provided in the embodiments of this application, regarding the energy storage converter and battery cluster; Figure 5 This is a topology diagram of the auxiliary power supply circuit of the energy storage system provided in the embodiments of this application; Figure 6 This is a structural diagram of the energy storage device provided in the embodiments of this application; Figure 7 This is another structural diagram of the energy storage device provided in the embodiments of this application; Figure 8 This is a flowchart of the control method for the energy storage system provided in the embodiments of this application.

[0028] Explanation of reference numerals in the attached figures: 10. Battery module; 11. Battery management system; 12. Battery cluster; 20. Energy storage converter; 30. Power detection unit; 40. Energy management system; 50. Power generation unit; 60. Load; 70. Transformer unit; 100. Enclosure; 110. Energy storage converter cabinet; 120. Distribution cabinet; 130. Control cabinet. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1 - Appendix Figure 8 This application will be described in further detail.

[0030] This application discloses an energy storage system. (Refer to...) Figure 1 The energy storage system is suitable for connection in parallel with the power generation unit 50 to an AC bus to supply power to the load 60. The energy storage system includes a battery module 10, an energy storage converter 20, a power detection unit 30, and an energy management system 40. The battery module 10 includes a battery management system 11 and battery clusters 12. The DC side of the energy storage converter 20 is connected to the battery clusters 12, and the AC side is connected to the AC bus, configured to operate in virtual synchronous machine mode. The power detection unit 30 is located at the input of the AC bus or the load 60 to collect power data from the load 60. The energy management system 40 is connected in parallel with the energy storage converter 20, the power storage converter 20, the power storage converter 30, and the power storage converter 40. The power detection unit 30, the battery management system 11, and the power generation unit 50 are connected in communication. The energy management system 40 is configured to acquire the real-time operating power of the power generation unit 50 and execute a power allocation strategy based on the power data of the load 60 fed back by the power detection unit 30: when the power data of the load 60 is lower than the lower limit of the preset power operating range of the power generation unit 50, the energy management system 40 controls the energy storage converter 20 to enter the charging state and absorb electrical energy from the AC bus to increase the output load of the power generation unit 50, so that the actual output power of the power generation unit 50 is maintained within the preset power operating range.

[0031] Specifically, taking a diesel generator set as the power generation unit 50 as an example, its rated power is 1000kW, and the preset power operating range is 70% to 90% of the rated power, that is, 700kW to 900kW. When the total power of the load 60 on the AC bus is only 500kW (below the lower limit of the range), the energy management system 40 obtains the load power data through the power detection unit 30, and then controls the energy storage converter 20 to enter the charging state, absorbing 200kW of surplus electrical energy from the AC bus, so that the actual output power of the diesel generator set is maintained in the high-efficiency range of 700kW.

[0032] The Virtual Synchronous Generator (VSG) mode refers to the energy storage converter 20 simulating the operating characteristics of a traditional synchronous generator. It has built-in active power-frequency droop curves and reactive power-voltage droop curves. When the power of the load 60 undergoes a step change, the energy storage converter 20 can autonomously adjust its output power based on the droop characteristics, suppressing voltage / frequency fluctuations of the AC bus within milliseconds and maintaining instantaneous system stability. Compared with the traditional constant power control mode (PQ mode), the energy storage converter 20 can only passively execute upper-level control commands and cannot sense instantaneous fluctuations in grid frequency and voltage. Therefore, when the load 60 undergoes a step change that causes the grid frequency to drop, traditional energy storage systems often cannot provide millisecond-level support and may even trigger protection shutdown due to the detection of frequency anomalies, further deteriorating grid stability. The power detection unit 30, on the other hand, collects the voltage and current signals of the AC bus and calculates the total power of the load 60 in real time, providing accurate data support for the power allocation strategy of the energy management system 40.

[0033] Understandably, the energy storage system works in parallel with the power generation unit 50. With the help of the virtual synchronous machine mode and power distribution strategy, when the power of the load 60 is lower than the power operating range of the power generation unit 50, the energy storage converter 20 absorbs the excess power, preventing the power generation unit 50 from falling into a low-load and inefficient state of "overpowered" operation. At the same time, it stabilizes the power quality, reduces the wear and tear of the power generation unit 50, and lowers the operation and maintenance costs and energy consumption.

[0034] In one embodiment, the energy storage converter 20 is configured to employ a droop control strategy: by monitoring the voltage amplitude and frequency of the AC bus, the active power output and reactive power output of the energy storage converter 20 are automatically adjusted using a preset droop coefficient to respond to power fluctuations of the load 60.

[0035] Specifically, refer to Figure 2 VSG mode has built-in Figure 2 (a) Active power (P) - frequency (f) droop curve and Figure 2 (b) The reactive power (Q) – voltage (V) droop curve: By real-time detection of the frequency deviation of the AC bus, based on the active power – frequency droop curve, the active power output of the energy storage converter 20 is automatically calculated and adjusted to smooth frequency fluctuations; by real-time detection of the voltage amplitude deviation of the AC bus, based on the reactive power – voltage droop curve, the reactive power output of the energy storage converter 20 is automatically calculated and adjusted to maintain voltage stability. This direct feedback control mechanism based on local electrical quantities (frequency, voltage) enables the energy storage converter 20 to respond autonomously within milliseconds, without relying on external communication commands. These two curves serve as "automatic adjustment rules," allowing the energy storage converter 20 to match the system state in real time.

[0036] The following uses specific data to illustrate the adjustment logic: Initially, the diesel generator set needs to maintain a high-efficiency output of 700kW, while load 60 only consumes 500kW. Therefore, the energy storage converter 20 needs to charge at a power of 200kW (power balance logic: 700kW generator set output = 500kW load consumption + 200kW energy storage charging). If the power of load 60 fluctuates slightly at this time (for example, it instantly increases to 550kW), it will directly cause a slight change in the voltage and frequency of the AC bus. The VSG mode can detect this change instantly and automatically fine-tune the charging power according to the built-in "automatic adjustment rules," reducing it from 200kW to 150kW. The corresponding power balance logic becomes: 700kW generator set output = 550kW load consumption + 150kW energy storage charging, ensuring that the output power of the diesel generator set remains stable at 700kW. At the same time, the reactive power-voltage droop curve responds in real time to the bus voltage deviation, dynamically adjusting the reactive power output to maintain the stability of the bus voltage and provide a reliable voltage basis for the adjustment of active power.

[0037] Understandably, the droop control strategy enables the energy storage converter 20 to quickly follow the power fluctuations of the load 60 and automatically adjust itself without the need for the energy management system 40 to issue commands in real time. This achieves millisecond-level response, suppresses voltage and frequency fluctuations caused by sudden load changes, and ensures power supply stability. The entire power fine-tuning process can be completed in milliseconds (equivalent to an instantaneous response). It can quickly suppress voltage and frequency fluctuations to prevent system instability and accurately absorb excess power, ultimately achieving the dual goals of "stable operation of the diesel generator set in the high-efficiency range and stable power supply to the load".

[0038] In one embodiment, the energy management system 40 is further configured to perform the following control: when the total power of the load 60 exceeds the upper limit of the preset power operating range of the power generation unit 50, the energy management system 40 controls the energy storage converter 20 to enter the discharge state and bear the load power exceeding the upper limit.

[0039] Specifically, taking a diesel generator set with a rated power of 1000kW and a preset range of 700kW~900kW as an example, when the total power of load 60 jumps from 800kW to 1100kW (exceeding the 900kW upper limit), the diesel generator set will face the risk of overload. At this time, the energy management system 40 issues a discharge command to control the energy storage converter 20 to bear the excess 200kW load power (i.e., 1100kW total load = 900kW generator output + 200kW energy storage discharge). At the same time, thanks to the droop characteristics of the virtual synchronous machine mode (VSG), the energy storage converter 20 can respond to the frequency drop caused by the load surge within milliseconds and actively output active power to support the grid voltage, thereby locking the output power of the diesel generator set at the safe upper limit of 900kW, which not only prevents the unit from being damaged due to overload, but also ensures the continuous power supply to load 60.

[0040] Understandably, for peak loads such as lifting drill pipes and starting high-power machines, the energy storage converter 20 quickly discharges to supplement the power gap, eliminating the need for too many generator units 50 to be online for extended periods. This satisfies peak power demand while keeping the generator units 50 operating within their power range, thus reducing equipment investment costs.

[0041] In one embodiment, the energy management system 40 is further configured to perform dynamic parameter adjustment: acquire the state of charge of the battery module 10 in real time, and dynamically correct the droop curve parameters of the energy storage converter 20 in virtual synchronous machine mode according to the state of charge value, so as to change the response sensitivity of the energy storage converter 20 to changes in voltage amplitude or frequency.

[0042] Specifically, refer to Figure 2 (a) shows the active-frequency (Pf) droop characteristic curve. The adjustment of the droop curve parameters is achieved by changing the slope of the curve. Figure 2 In (a), the horizontal axis represents frequency f, and the vertical axis represents active power P. When the energy management system 40 detects that the state of charge (SOC) of the battery module 10 is close to a preset high threshold (e.g., 90%), to prevent overcharging risks, the system will increase the slope of the Pf droop curve, making the curve steeper. Taking the same amplitude frequency increase (from fN to f1) as an example, at the original slope, the charging power of the energy storage converter 20 will increase from PN to P1; however, after the slope is increased, the power increment ΔP under the same frequency change will be significantly reduced, thereby avoiding high-power charging of the battery when it is in a high-charge state. Conversely, when the SOC is close to a low threshold (e.g., 10%), the system will... Figure 2 (a) The active-frequency (Pf) droop curve performs a similar slope adjustment: increasing the slope of the curve significantly reduces the discharge power increment ΔP under the same frequency change, thereby preventing the battery from discharging at high power when the battery is low in charge. This SOC-based dynamic parameter tuning mechanism enables the output characteristics of the energy storage converter 20 to adapt to the remaining battery charge, thereby maintaining the stable operation of the system while ensuring the battery safety boundary.

[0043] In one embodiment, the preset power operating range is set to 50% to 95% of the rated power of the power generation unit 50, preferably 70% to 90%. This range matches the efficient operating range of the power generation unit 50 (such as a diesel generator set), which can minimize fuel consumption, reduce unit wear, balance power generation efficiency and equipment lifespan, and further reduce overall operation and maintenance costs.

[0044] Reference Figure 3In one embodiment, a system structure diagram of the energy storage system of this application is shown. The power generation unit 50 is specifically two diesel generators. The dual-generator configuration can achieve redundancy backup. When one generator fails or is under maintenance, the other generator can continue to supply power, which improves the reliability and continuity of the system. In other embodiments, the power generation unit 50 can also be a gas generator, a gasoline generator, a fuel cell unit, or a mains power interface connected to the grid, to adapt to different application scenarios and energy supply needs. The battery module 10 adopts a modular design, including a high-voltage box and battery clusters 12. Each high-voltage box manages several battery packs (battery clusters 12), and the capacity can be flexibly configured to meet different power requirements. Its supporting battery management system 11 collects the voltage, current, temperature and other status parameters of each battery pack in real time through the CAN bus, so as to realize the fine monitoring and protection of the battery module 10 and prevent overcharging, over-discharging and thermal runaway. Meanwhile, the battery management system 11 is also connected to environmental monitoring equipment via an RS485 bus, including a UPS uninterruptible power supply, air conditioner, water immersion sensor, and temperature controller. The UPS uninterruptible power supply provides continuous power to the entire monitoring and communication system, preventing data loss or equipment malfunction due to power outages; the air conditioner and temperature controller work together to adjust the cabinet temperature in real time, ensuring that the battery and power electronic equipment operate within a suitable temperature range; the water immersion sensor monitors the water accumulation at the bottom of the cabinet, triggering an alarm once water immersion is detected, further enhancing the system's safety and stability. The energy storage converter 20 adopts a multi-machine parallel architecture, with multiple energy storage converter 20 units working together. It can be flexibly expanded to match the system power demand. At the same time, it supports the virtual synchronous machine mode, which can autonomously participate in grid frequency and voltage regulation, smooth power fluctuations within milliseconds, and improve power quality. The power detection unit 30 consists of an electricity meter and a current transformer (CT). The electricity meter acts as the detection element, and the current transformer collects the voltage and current signals of the AC bus in real time. After calculation, it obtains accurate load power data and uploads the data to the energy management system 40 to provide data support for power distribution and dynamic adjustment. The AC bus also has a power supply port for powering internal loads or circuit modules. The transformer unit 70 is used to match the system voltage level, realize high-low voltage conversion, and meet the power demand of different loads 60; the loads 60 may include industrial loads and plant auxiliary loads, and the system can give priority to ensuring the power supply of loads 60. The entire system constructs a hierarchical communication network: the battery management system 11 communicates with the high-voltage box and energy storage converter 20 in real time via a CAN bus to ensure the real-time communication of the underlying devices; the battery management system 11 is connected to the environmental monitoring equipment via an RS485 bus to achieve comprehensive perception of the environment inside the cabinet; the battery management system 11 is connected to the switch via a LAN network to achieve information interaction with the upper-level energy management system 40, taking into account both communication reliability and transmission efficiency.

[0045] Understandably, the energy management system 40 works in conjunction with each unit to dynamically allocate power based on the power of the load 60 and the operating status of the power generation unit 50. This prevents the power generation unit 50 from operating inefficiently under low load and from being damaged by overload. At the same time, it dynamically adjusts the droop curve parameters in conjunction with the state of charge of the battery module 10 to ensure battery safety.

[0046] Reference Figure 4 In one embodiment, the DC-side topology of the energy storage system of this application is illustrated. The energy storage converter 20 adopts a multi-machine parallel architecture, with four energy storage converter 20 units working collaboratively. They are connected to the high-voltage box and battery cluster 12 via a DC bus, allowing for flexible capacity expansion to match system power requirements. Each energy storage converter 20 unit supports virtual synchronous machine mode, enabling it to autonomously participate in grid frequency and voltage regulation, smoothing power fluctuations within milliseconds and significantly improving power quality. The high-voltage box serves as the power interface between the battery pack and the energy storage converter 20, responsible for the on / off control and status acquisition of the battery pack, and realizing overload and short-circuit protection for the battery pack. Multiple high-voltage boxes and battery packs are connected in parallel via a DC bus, allowing for flexible capacity configuration to meet different power requirements, while also improving system redundancy and reliability. In addition, the system is equipped with a bidirectional power supply interface (power supply interface 1) to provide AC input and output to the energy storage converter 20 units, ensuring the normal operation of the system.

[0047] Reference Figure 5 In one embodiment, a topology diagram of the auxiliary power supply circuit of the energy storage system of this application is shown. The auxiliary power supply interface serves as the power input of the entire circuit. After passing through the main circuit breaker (QF20, all QF series in the attached figure are circuit breakers), the power is supplied to different loads through multiple branch circuit breakers, realizing hierarchical protection and flexible control of the power supply circuit.

[0048] One branch supplies power to environmental protection equipment such as air conditioners, axial fans, lighting, and feeder boxes. The air conditioner and axial fans work together to regulate the temperature inside the cabinet, ensuring that the batteries and power electronic equipment operate within a suitable temperature range. The other branch, after passing through a UPS uninterruptible power supply, supplies power to the circuit breaker control loop, controller, and high-voltage box. Even if the main power supply is interrupted, the UPS can continue to provide power to the control and communication equipment, preventing data loss or system malfunction. In addition, the circuit also integrates a 24V switching power supply to provide a stable DC power supply for the low-voltage control circuit, further improving the reliability of the system.

[0049] Through this modular power supply design, the auxiliary power supply circuit enables stable power supply and refined management of all auxiliary equipment within the system, providing a solid guarantee for the safe and continuous operation of the entire energy storage system.

[0050] Reference Figure 6 and Figure 7 This application also discloses an energy storage device, including a housing 100 and an energy storage system as described in any of the above embodiments disposed within the housing 100.

[0051] The entire system is integrated within the enclosure 100 and adopts a layered modular layout. The space at the top of the enclosure 100 is used to house the battery clusters 12, which can be quickly installed and expanded through modular brackets. The lower space houses the energy storage converter cabinet 110, the power distribution cabinet 120, and the control cabinet 130. Each functional cabinet is independently partitioned and connected to the power and communication systems through internal wiring channels. The system features a compact structure, small footprint, and rapid deployment. To address heat dissipation and electromagnetic compatibility requirements, the energy storage converter cabinet 110 is equipped with an axial fan and ventilation holes to form a directional airflow. The distribution cabinet 120 and control cabinet 130 are electromagnetically shielded by a metal frame, enabling them to adapt to complex outdoor environments such as high temperature and high humidity. In addition, the enclosure 100 is equipped with status indicator lights and a display screen. The indicator lights include power, run, fault, and alarm lights, which can intuitively reflect the system's operating status. The display screen is used to display key parameters such as real-time voltage, current, and battery state of charge, making it easier for maintenance personnel to quickly grasp the details of system operation and troubleshoot problems, further improving the system's practicality and environmental adaptability.

[0052] Reference Figure 8 This application also discloses a control method for an energy storage system, including the following steps: S1. Establish data interaction between the energy management system 40 and the controller of the external power generation unit 50 to obtain the real-time electrical parameters of the power generation unit 50; S2. Control the energy storage converter 20 to operate in virtual synchronous machine mode, follow load fluctuations based on voltage-frequency droop characteristics, and monitor the total power of the load 60 in real time; compare the total power of the load 60 with the preset power operating range of the power generation unit 50; when the total power of the load 60 is detected to be lower than the lower limit of the preset power operating range, generate a charging command and send it to the energy storage converter 20 to control the battery cluster 12 to charge, so as to increase the load rate of the power generation unit 50 and keep the power generation unit 50 within the preset power operating range; and / or, when the total power of the load 60 is detected to be higher than the upper limit of the preset power operating range, generate a discharging command to compensate for the load power gap.

[0053] Specifically, taking a diesel generator set with a rated power of 1000kW and a preset power operating range of 700kW~900kW as an example, the energy management system 40 establishes data interaction with the diesel generator set controller to obtain electrical parameters such as the unit's output power, operating frequency, and voltage in real time; at the same time, it controls the energy storage converter 20 to operate in virtual synchronous machine mode, using its voltage-frequency droop characteristics to follow the power changes of the load 60 in real time. When the total power of the load 60 drops sharply from 800kW (within the preset range) to 600kW (below the 700kW lower limit), the diesel generator set will face the risk of low-load and inefficient operation. At this time, the energy management system 40 captures the load fluctuation in real time through the power detection unit 30, generates a charging command after comparison and confirmation, and sends it to the energy storage converter 20. Upon receiving the command, the energy storage converter 20 controls the battery cluster 12 to initiate the charging process, actively absorbing 100kW of power (i.e., 600kW total load power + 100kW battery charging power = 700kW generator output power), thereby increasing the output power of the diesel generator set to the lower limit of the preset range, 700kW. During this process, thanks to the rapid response characteristics of the virtual synchronous machine mode, the energy storage converter 20 can adjust the charging power within milliseconds, ensuring that the diesel generator set always maintains stable operation within the preset power operating range. Conversely, if the total power of the load 60 is detected to suddenly exceed the upper limit of the preset power operating range (e.g., instantaneously increasing to 950kW), the diesel generator set will face the risk of overload tripping. At this time, the energy management system 40 generates a discharge command and sends it to the energy storage converter 20. After responding to the command, the energy storage converter 20 controls the battery cluster 12 to start the discharge process and actively outputs 50kW of power to compensate for the load power gap (i.e., 950kW total load power - 50kW battery discharge power = 900kW generator output power), thereby limiting the output power of the diesel generator set to the upper limit of the preset range of 900kW, preventing the generator set from shutting down due to overload and ensuring the continuity of power supply.

[0054] Understandably, this application constructs a closed-loop control logic of "data interaction - mode control - power monitoring - command execution" to ensure that the power generation unit 50 operates within the preset power range and responds quickly to load fluctuations. This improves the problem of low operating efficiency and poor fuel economy caused by the "overpowered" power generation unit 50 due to low load rate in traditional solutions. When the load power is higher than the power operating range of the power generation unit, the energy storage converter releases electrical energy to provide instantaneous power support, preventing the power generation unit from shutting down or undergoing derating protection due to overload, and ensuring the continuity of power supply.

[0055] In one embodiment, in step S2, during the process of controlling the battery cluster 12 to charge, the change trend of the state of charge of the battery cluster 12 is calculated in real time. When the state of charge reaches the preset overcharge prevention threshold, the energy management system 40 sends a speed adjustment command to the controller of the power generation unit 50 to reduce the mechanical power output of the power generation unit 50.

[0056] Specifically, during the process of battery cluster 12 executing charging commands to maintain the high-load operation of power generation unit 50, energy management system 40 continuously monitors the voltage and current integral of battery module 10 and calculates the rising trend of state of charge (SOC) in real time. When the SOC is detected to be close to the preset overcharge prevention threshold (e.g., 95%), in order to prevent the risk of overcharging due to continuous charging of battery module 10, energy management system 40 will stop sending charging commands to energy storage converter 20 and send speed regulation commands to the controller of power generation unit 50. Taking a diesel generator set with a rated power of 1000kW as an example, assuming that the power of load 60 is 600kW at this time, the battery is charging at a power of 100kW to maintain the unit at the economic operating point of 700kW. When the battery SOC reaches the overcharge protection threshold, the energy management system 40 sends a load reduction command to the generator set, controlling its throttle or prime mover speed to smoothly reduce its mechanical power output to 600kW. This ensures that the output power of the generator unit 50 is rebalanced with the power of the actual load 60 while stopping battery charging, preventing the generator unit 50 from being overloaded or running out of control or overspeeding due to the sudden disconnection of the charging load.

[0057] Understandably, combining the battery's state of charge with the output regulation of the power generation unit 50 forms a dual protection mechanism, which not only prevents damage from overcharging the battery but also ensures that the output of the power generation unit 50 is precisely matched with the load 60's requirements, maintaining the system's long-term stable operation.

[0058] In one embodiment, the control method for the energy storage system further includes the step of: S3. Perform two-stage regulation control to address step changes in load power: When a step change in the power of load 60 is detected, the energy storage converter 20 first automatically adjusts its output power based on the droop characteristic to complete the first adjustment; then the energy management system 40 recalculates and issues the power setpoint for the energy storage converter 20 based on the total power data of the changed load 60 to complete the second adjustment, and locks the output power of the power generation unit 50 back into the preset power operating range.

[0059] Specifically, taking a diesel generator set with a rated power of 1000kW and a preset economic operating range of 700kW~900kW as an example, assuming that the system is currently in a steady state, the generator set outputs 700kW, of which 600kW supplies the actual load 60 and 100kW supplies the energy storage converter 20 for charging.

[0060] When the load power increases dramatically, such as by 150kW instantaneously, the output power of the diesel generator set cannot immediately follow the change due to its mechanical inertia. At this time, the energy storage converter 20 utilizes the fast response characteristics of its power electronic devices and automatically senses the frequency or power deviation based on the droop control characteristics, and instantaneously outputs 150kW of active power to fill the gap. This process is called regulation, which smooths out the power oscillation caused by the sudden change in load.

[0061] Subsequently, the energy management system 40 recalculates the target output of the generator unit 50 based on the new load power data (600kW + 150kW = 750kW) uploaded by the power detection unit 30. To maintain the generator set within the economic range, the energy management system 40 issues a new power setting value to the energy storage converter 20 (adjusting the charging power from 100kW to 150kW). The energy storage converter 20, following this instruction, gradually reduces the discharge power until it stops discharging and switches to charging mode, thereby increasing and locking the output power of the diesel generator set back to 800kW (750kW load + 50kW charging). This process is known as secondary regulation.

[0062] Understandably, the first-level regulation achieves millisecond-level rapid response and suppresses instantaneous power fluctuations; the second-level regulation achieves precise power locking and ensures that the power generation unit 50 remains stable within the power range for a long period of time. The combination of the two measures balances response speed and regulation accuracy, improving the system's ability to cope with complex load changes.

[0063] In one embodiment, the control method for the energy storage system further includes the step of: S4. Perform thermal runaway protection and electrical isolation: The energy management system 40 monitors the fire alarm signal or temperature extreme value of the battery cluster 12; when it receives the thermal runaway alarm signal, the energy management system 40 executes a two-way blocking strategy: on the DC side, it blocks the pulse output of the energy storage converter 20 and controls the DC circuit breaker of the battery cluster 12 to open in order to cut off the DC arc. On the AC side, an isolation command is sent to the power generation unit 50 via the communication interface to control the power generation unit 50 to disconnect from the AC bus.

[0064] Specifically, the energy management system 40 receives real-time signals from the battery management system 11 regarding the temperature, voltage, and smoke detection of individual cells in the battery cluster 12. Once the internal temperature of the battery cluster 12 exceeds a preset safety threshold (e.g., 60°C) or a clear thermal runaway alarm signal is received, the system triggers the highest priority safety protection logic.

[0065] On the DC side, the energy management system 40 first sends an emergency stop command to the energy storage converter 20, forcibly blocking the pulse output of the power switching transistor (IGBT) inside the energy storage converter 20, causing the energy storage converter 20 to stop working and eliminating the energy source that causes arcing on the DC side; then, the control signal drives the DC circuit breaker (or contactor) on the battery cluster 12 side to operate, achieving physical electrical isolation and cutting off the DC energy path between the battery module 10 and the outside.

[0066] On the AC side, the energy management system 40 synchronously sends an emergency shutdown or isolation command to the power generation unit 50 (such as a diesel generator controller) through the communication interface, controlling the main circuit breaker of the power generation unit 50 to trip and cut off the energy input on the AC side.

[0067] After confirming that the electrical connection is broken, the energy management system 40 outputs a switch signal to trigger the automatic fire extinguishing device (such as a perfluorohexanone or heptafluoropropane fire extinguishing system) configured inside the enclosure 100. The extinguishing medium is rapidly released through atomizing nozzles arranged around the battery cluster 12, quickly suppressing the thermal runaway reaction of the battery and preventing reignition through a dual mechanism of heat absorption and oxygen isolation.

[0068] Understandably, by implementing the synchronous operation of the DC and AC sides, a bidirectional electrical blockade is implemented to address the risk of battery thermal runaway. This prevents external current from flowing back into the faulty battery and also prevents the risk of arcing from spreading from the faulty battery to the outside, thereby curbing the spread of fire, preventing the fault from escalating, ensuring the safety of equipment and personnel, and improving the safety protection level of the system.

[0069] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An energy storage system, characterized in that, The energy storage system is used to connect in parallel with the power generation unit (50) to an AC busbar to supply power to the load (60), and includes: The battery module (10) includes a battery management system (11) and a battery cluster (12). The energy storage converter (20), connected to the battery cluster (12) on the DC side and connected to the AC bus on the AC side, is configured to operate in virtual synchronous machine mode; A power detection unit (30) is disposed at the input end of the AC bus or the load (60) for collecting power data of the load (60); The energy management system (40) is communicatively connected to the energy storage converter (20), the power detection unit (30), the battery management system (11), and the power generation unit (50). The energy management system (40) is configured to acquire the real-time operating power of the power generation unit (50) and execute a power allocation strategy based on the power data of the load (60) fed back by the power detection unit (30). When the power data of the load (60) is lower than the lower limit of the preset power operating range of the power generation unit (50), the energy management system (40) controls the energy storage converter (20) to enter the charging state and absorb electrical energy from the AC bus to increase the output load of the power generation unit (50) so that the actual output power of the power generation unit (50) is maintained within the preset power operating range.

2. The energy storage system according to claim 1, characterized in that, The energy storage converter (20) is configured to adopt a droop control strategy: by monitoring the voltage amplitude and frequency of the AC bus, the active power output and reactive power output of the energy storage converter (20) are automatically adjusted using a preset droop coefficient to respond to the power fluctuations of the load (60).

3. The energy storage system according to claim 1, characterized in that, The energy management system (40) is also configured to perform the following control: when the total power of the load (60) exceeds the upper limit of the preset power operating range of the power generation unit (50), the energy management system (40) controls the energy storage converter (20) to enter the discharge state and bear the load power exceeding the upper limit.

4. The energy storage system according to claim 1, characterized in that, The energy management system (40) is also configured to perform dynamic parameter adjustment: acquire the state of charge of the battery module (10) in real time, and dynamically correct the droop curve parameters of the energy storage converter (20) in virtual synchronous machine mode according to the state of charge value, so as to change the response sensitivity of the energy storage converter (20) to changes in voltage amplitude or frequency.

5. The energy storage system according to claim 1, characterized in that, The preset power operating range is set to 70% to 90% of the rated power of the power generation unit (50).

6. An energy storage device, characterized in that, It includes a housing (100) and an energy storage system as described in any one of claims 1-5 disposed on the housing (100).

7. A control method for an energy storage system, characterized in that, Including the following steps: S1. Establish data interaction between the energy management system (40) and the controller of the external power generation unit (50) to obtain the real-time electrical parameters of the power generation unit (50); S2. Control the energy storage converter (20) to operate in virtual synchronous machine mode, follow the load fluctuation based on the voltage-frequency droop characteristic, and monitor the total power of the load (60) in real time; compare the total power of the load (60) with the preset power operating range of the power generation unit (50), and when the total power of the load (60) is detected to be lower than the lower limit of the preset power operating range, generate a charging command and send it to the energy storage converter (20) to control the battery cluster (12) to charge, so as to increase the load rate and keep the power generation unit (50) within the preset power operating range; And / or, when the total power of the load (60) is detected to be higher than the upper limit of the preset power operating range, a discharge command is generated to compensate for the load power shortfall.

8. The control method according to claim 7, characterized in that, In step S2, during the process of controlling the battery cluster (12) to charge, the change trend of the state of charge of the battery cluster (12) is calculated in real time. When the state of charge reaches the preset overcharge prevention threshold, the energy management system (40) sends a speed adjustment command to the controller of the power generation unit (50) to reduce the mechanical power output of the power generation unit (50).

9. The control method according to claim 7, characterized in that, It also includes the following steps: S3. Perform two-stage regulation control to address step changes in load power: When a step change in the power of the load (60) is detected, the energy storage converter (20) first automatically adjusts its output power based on the droop characteristic to complete the first adjustment; then the energy management system (40) recalculates the power setpoint for the energy storage converter (20) based on the total power data of the changed load (60) and issues it to complete the second adjustment, and locks the output power of the power generation unit (50) back into the preset power operating range.

10. The control method according to claim 7, characterized in that, It also includes the following steps: S4. Perform thermal runaway protection and electrical isolation: The energy management system (40) monitors the fire alarm signal or temperature extreme value of the battery cluster (12); when a thermal runaway alarm signal is received, the energy management system (40) executes a two-way blocking strategy: on the DC side, it blocks the pulse output of the energy storage converter (20) and controls the DC circuit breaker of the battery cluster (12) to open in order to cut off the DC arc. On the AC side, an isolation command is sent to the power generation unit (50) through the communication interface to control the power generation unit (50) to disconnect from the AC bus.

Images