Intelligent power supply energy storage system

Abstract

An intelligent power supply and energy storage system includes an AC power grid, an energy storage battery, a first anti-reverse current device, a second anti-reverse current device, and a controllable switch array; a first power conversion module connected to the output of the AC power grid; a black-start auxiliary power module connected to the output of the first power conversion module; a battery undervoltage trip protection unit connected to the output of the energy storage battery and the black-start auxiliary power module; a soft-start circuit connected to the output of the battery undervoltage trip protection unit; a second power conversion module connected to the output of the soft-start circuit; a low-voltage DC bus connected to the outputs of the first and second anti-reverse current devices; and an intelligent control and management unit, whose outputs are respectively connected to the AC power grid, the energy storage battery, the first power conversion module, the low-voltage DC bus, and the controllable switch array, for performing power selection, load hierarchical management, and status monitoring. This invention achieves intelligent power supply such as eliminating single-point faults, precise over-discharge protection, and autonomous black-start.

Description

Technical Field

[0001] This invention relates to the field of energy storage system technology, and more specifically to an intelligent power supply and energy storage system. Background Technology

[0002] Energy storage systems typically include key components such as battery clusters, battery management systems (BMS), inverters (PCS), energy management systems (EMS), and thermal management systems. Among these, the stable operation of low-voltage auxiliary loads, such as the control boards of the BMS, PCS, and EMS, is a prerequisite for ensuring the safety of the energy storage system.

[0003] Currently, auxiliary power supply for energy storage systems suffers from the following technical defects: 1. Single point of failure risk: Single-circuit AC power supply relies on the external power grid, and the system collapses when the grid loses power; single-circuit battery power cannot operate when the battery is deeply discharged or not connected. 2. Battery over-discharge risk: Although existing redundancy schemes can maintain power supply, during prolonged grid outages, the auxiliary system will continuously consume battery energy, leading to battery over-discharge and permanent damage. 3. Limited power strategy: The lack of a power selection strategy makes it impossible to dynamically adjust based on electricity prices or battery status, resulting in high operating costs. 4. Difficult start-up: The lack of an effective black-start mechanism during the battery pack's complete de-energization or equipment installation and commissioning phases makes system initialization difficult. Summary of the Invention

[0004] The purpose of this invention is to provide an intelligent power supply and energy storage system with multiple protections and energy management to solve the problem of insufficient reliability of energy storage systems in the prior art due to single point of failure, battery over-discharge, single power supply strategy and difficulty in starting.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] The system includes an AC power grid, an energy storage battery, and a load; a first power conversion module connected to the output of the AC power grid for converting AC power to first DC power; a black-start auxiliary power module connected to the output of the first power conversion module for activating the battery power supply path via the AC power grid when the energy storage battery is depleted; a battery undervoltage trip protection unit connected to the output of the energy storage battery and the black-start auxiliary power module; a soft-start circuit connected to the output of the battery undervoltage trip protection unit; a second power conversion module connected to the output of the soft-start circuit for converting high-voltage DC power to second DC power; a first anti-reverse current device connected to the output of the first power conversion module; a second anti-reverse current device connected to the output of the second power conversion module; a low-voltage DC bus connected to the outputs of the first and second anti-reverse current devices for providing operating power to the load; a controllable switch array connected to the output of the low-voltage DC bus; and an intelligent control management unit whose output is electrically connected to the AC power, energy storage battery, first power conversion module, low-voltage DC bus, and controllable switch array for performing power selection, load hierarchical management, and status monitoring.

[0007] Furthermore, the battery undervoltage trip protection unit includes a voltage sampling module for real-time acquisition of the energy storage battery voltage; and a controllable switch connected in series between the energy storage battery and the input terminal of the second power conversion module.

[0008] Furthermore, the intelligent control management unit is used to control the on / off state of the controllable switch; the intelligent control management unit is preset with a first threshold and a second threshold of battery voltage, which are used to control the on / off state of the controllable switch.

[0009] Furthermore, when the battery voltage is lower than the second threshold, the intelligent control management unit controls the controllable switch to open; when the battery voltage recovers to a level higher than the first threshold, the intelligent control management unit controls the controllable switch to close.

[0010] Furthermore, the load includes a critical load and a switchable load. The input terminal of the critical load is electrically connected to the output terminal of the low-voltage DC bus, and the input terminal of the switchable load is electrically connected to the output terminal of the controllable switch array.

[0011] Furthermore, the intelligent control management unit is used to control the controllable switch array to disconnect and disconnect the switchable load when it detects a power grid failure and the energy storage battery voltage is lower than a third threshold, so as to maintain power supply to only the critical load.

[0012] Furthermore, the first threshold is 40% of the nominal voltage of the energy storage battery, the second threshold is 15% of the nominal voltage of the energy storage battery, and the third threshold is 25% of the nominal voltage of the energy storage battery.

[0013] Furthermore, the intelligent control management unit prioritizes the use of the first power conversion module for power supply during off-peak hours when the grid electricity price is low, and prioritizes the use of the second power conversion module for power supply during peak hours when the grid electricity price is high.

[0014] Furthermore, the soft-start circuit includes a pre-charge resistor and a bypass switch connected in parallel.

[0015] Furthermore, both the first and second anti-reverse current devices are power diodes, and their conduction direction is directed towards the low-voltage DC bus.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. Eliminate single points of failure. This system features two independent power supply circuits: an external AC power grid and an energy storage battery. These circuits are converted from AC to DC and from high to low voltage via first and second power conversion modules, respectively. Combined with the anti-reverse current device built into the DC combiner unit, the two power supplies are independently connected in parallel to the low-voltage DC bus, serving as backups for each other. This effectively solves the problems of traditional single-circuit power supply relying on the power grid and the limited power draw from a single battery, preventing the entire auxiliary system from collapsing due to grid failure or battery malfunction, and ensuring a continuous and stable power supply to the energy storage auxiliary load.

[0018] 2. Precise Over-Discharge Prevention. This system incorporates a battery undervoltage trip protection unit. Through real-time voltage sampling and graded threshold logic control of the controllable switch, it automatically cuts off the battery power supply circuit when the battery voltage is low and automatically reconnects the switch to resume operation after the voltage recovers. Simultaneously, a soft-start circuit is used to suppress inrush current. This dual approach, addressing both hardware and control aspects, avoids the problem of continuous battery depletion and deep over-discharge during prolonged power outages, preventing irreversible cell damage and extending the lifespan of the energy storage battery.

[0019] 3. Intelligent Energy Management. This system relies on an intelligent control and management unit to prioritize grid power supply during off-peak hours and switch to battery power supply when battery power is sufficient during peak hours, thereby achieving peak-shifting energy use and optimized load allocation. At the same time, it can monitor the system's operating status in real time, enabling autonomous power switching and refined energy consumption control. This solves the drawbacks of traditional power supply modes, such as lack of strategic scheduling and low energy utilization, and effectively reduces the long-term operating costs of the system.

[0020] 4. Autonomous Black Start. This system is equipped with a black start circuit, which relies on the grid power supply to provide control power to the undervoltage trip protection unit. In scenarios such as when the battery is completely depleted, during equipment installation and commissioning, or during power outages, the system can actively activate the battery power supply path to achieve autonomous initialization and black start of the system in the absence of mains power and under low power conditions, which greatly reduces the difficulty of equipment commissioning, fault recovery, and on-site debugging. Attached Figure Description

[0021] Figure 1 This is a flowchart of the intelligent power supply and energy storage system of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be further described in detail below with reference to the accompanying drawings. Obviously, the embodiments described in this invention are only a part of the embodiments, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0023] like Figure 1 As shown, an intelligent power supply and energy storage system includes:

[0024] The intelligent control management unit and the AC power grid electrically connected to the output of the intelligent control management unit.

[0025] The energy storage battery's input is electrically connected to the intelligent control and management unit. Its output passes sequentially through a battery undervoltage trip protection unit, a pre-charge circuit, and a DC / DC conversion module, outputting 24V, which is then fed into the 24V low-voltage DC bus via diode D2. During off-peak hours, the intelligent control and management unit prioritizes power supply from the first power conversion module to charge the energy storage battery; during peak hours, the intelligent control and management unit prioritizes power supply from the second power conversion module to discharge the energy storage battery.

[0026] The first power conversion module, whose input terminal is electrically connected to the AC power grid and the intelligent control management unit, is used to convert AC power into DC power. The AC power grid is electrically connected to the first power conversion module, outputting 24V DC power, which is fed into the 24V low-voltage DC bus via diode D1.

[0027] The black-start auxiliary power module, with its input electrically connected to the output side of the first power conversion module, is used to activate the battery power supply path via the AC grid when the energy storage battery is depleted. The black-start auxiliary power module draws power from the output side of the first power conversion module, converts it into a control voltage, and provides initial activation power to the coil of the battery undervoltage trip protection unit and the control terminal of the second power conversion module. By configuring a black-start circuit, relying on grid power to provide control power to the undervoltage trip protection unit, it can actively activate the battery power supply path in scenarios where the battery is completely depleted, during installation and commissioning, or during power outages. This enables autonomous initialization and black-start of the system in a state of no mains power assistance and low power, significantly reducing the difficulty of equipment commissioning, fault recovery, and on-site debugging.

[0028] The battery undervoltage trip protection unit is electrically connected to the energy storage battery and the black-start auxiliary power module at its input. It includes a voltage sampling module for real-time voltage acquisition of the energy storage battery and a controllable switch (not shown in the diagram) connected in series between the energy storage battery and the input of the second power conversion module. The battery undervoltage trip protection unit controls the on / off state of the controllable switch through real-time voltage sampling and graded threshold logic. When the battery voltage is low, the battery power supply circuit is automatically cut off; after the voltage recovers, the circuit is automatically reconnected. Simultaneously, a soft-start circuit is used to suppress inrush current. This dual approach, from hardware to control, avoids the problem of continuous battery depletion and deep over-discharge during long-term power outages, preventing irreversible cell damage and extending the lifespan of the energy storage battery. This achieves precise over-discharge protection and long-term protection of the energy storage battery.

[0029] The soft-start circuit, whose input is electrically connected to the battery undervoltage trip protection unit, includes a pre-charge resistor and a bypass switch (not shown in the figure) connected in parallel, and is connected in series between the second power conversion module and the battery undervoltage trip protection unit.

[0030] The second power conversion module has its input terminal electrically connected to the soft-start circuit, which is used to convert high-voltage DC into a second DC.

[0031] The first and second anti-reverse current devices are connected, with the output of the first power conversion module connected to the low-voltage DC bus via the first anti-reverse current device, and the output of the second power conversion module connected to the low-voltage DC bus via the second anti-reverse current device. Both the first and second anti-reverse current devices are directed towards the low-voltage DC bus. Preferably, power diodes are used as anti-reverse current devices to prevent circulating current and backflow interference between the two power sources, providing strong anti-interference and adaptability. The dual-circuit modular design features high integration, strong compatibility, and a safe and reliable overall structure, making it suitable for various auxiliary power supply scenarios in energy storage power stations and highly valuable for widespread application.

[0032] The low-voltage DC bus is electrically connected at its input end to the first anti-reverse current device, the second anti-reverse current device, and the intelligent control and management unit, and at its output end to the load, and is used to provide working power to the load of the energy storage system.

[0033] The controllable switch array is electrically connected to the low-voltage DC bus and the intelligent control management unit at its input. It enables tiered load shedding and control, enhancing fault tolerance under extreme conditions. When the power grid fails and the battery is low, it automatically disconnects unnecessary loads, concentrates power to ensure the operation of core equipment, and rationally balances battery energy consumption, further strengthening system stability and endurance under extreme conditions.

[0034] The loads preferably include critical loads and switchable loads. The critical load input is electrically connected to the low-voltage DC bus, and the switchable load input is electrically connected to a controllable switch array.

[0035] The output of the intelligent control and management unit is connected to AC power, energy storage battery, first power conversion module, low-voltage DC bus, and controllable switch array, respectively, and is used to perform power selection, load hierarchical management and status monitoring, and to collect grid status, battery voltage, current, SOC and status of each module in real time.

[0036] The intelligent control management unit has preset first and second threshold values ​​for the battery voltage, which are used to control the on / off state of the controllable switch in the battery undervoltage trip protection unit. When the battery voltage is lower than the second threshold value, the intelligent control management unit controls the controllable switch to open; when the battery voltage recovers to above the first threshold value, the intelligent control management unit controls the controllable switch to close. Preferably, the first threshold value is 40% of the nominal voltage of the energy storage battery, and the second threshold value is 15% of the nominal voltage of the energy storage battery.

[0037] The intelligent control management unit is also used to control the controllable switch array to disconnect and disconnect switchable loads when a power grid failure is detected and the energy storage battery voltage is lower than a third threshold, thus maintaining power supply only to critical loads. Preferably, the third threshold is 25% of the nominal voltage of the energy storage battery.

[0038] The intelligent control and management unit combines time-of-use electricity price information and battery SOC status to optimize power supply strategies. During off-peak hours, it prioritizes the use of the first power conversion module, while during peak hours, it prioritizes the use of the second power conversion module. Prioritizing grid power during off-peak hours and switching to battery power when battery charge is sufficient during peak hours achieves staggered energy use and optimized load allocation. Simultaneously, it can monitor system operating status in real time, reducing operational energy consumption. This enables autonomous power switching and refined energy consumption control, overcoming the drawbacks of traditional power supply modes, such as lack of strategic scheduling and low energy utilization, and effectively reducing long-term system operating costs.

[0039] The working principle of the energy storage redundancy intelligent power supply system of this invention is as follows:

[0040] By setting up two independent power supply circuits—one for the AC power grid and one for the energy storage battery—and converting AC / DC and high / low voltage power through the first and second power conversion modules respectively, the two power supplies are independently connected in parallel to the low-voltage DC bus, serving as backups for each other. This effectively solves the problems of traditional single-circuit power supply relying on the power grid and single energy storage battery having limited power access, preventing the entire auxiliary system from paralyzing due to power grid failure or energy storage battery malfunction. It ensures continuous and stable power supply to the energy storage auxiliary load, thereby eliminating single-point failures and significantly improving power supply reliability.

[0041] Under normal operating conditions, the intelligent control and management unit detects that the current electricity price is during off-peak hours. Ideally, when the battery SOC > 30%, the system sets the first power conversion module as the primary power supply, and the second power conversion module as a backup. All loads are supplied with normal power. Simultaneously, the system utilizes off-peak electricity to charge the battery via the PCS, improving the economic efficiency of the energy storage system.

[0042] In the event of a power grid failure, the output voltage of the first power conversion module drops, diode D1 is reverse-biased and diode D2 is naturally turned on, and the second power conversion module seamlessly takes over the power supply, ensuring uninterrupted operation of the BMS and EMS.

[0043] After the intelligent control and management unit detects a power grid failure, it activates the "islanding protection logic". If the battery voltage is higher than 25% of the nominal voltage, it maintains power supply to all loads. If the battery voltage continues to drop to 25% of the nominal voltage, the system automatically disconnects the controllable switch array, cuts off non-critical loads such as fans and lighting, and only maintains power supply to the BMS main control and EMS core, extending the critical monitoring time by 3-5 times.

[0044] In severe under-voltage conditions, if the power grid fails to restore power for an extended period and the battery voltage continues to drop to 15% of its nominal voltage, the controllable switch in the battery under-voltage trip protection unit will trip, physically cutting off the input power to the second power conversion module. The system will then be completely powered down, and the battery itself will no longer consume any power, ensuring that the battery is not damaged due to over-discharge. At this time, the BMS main controller enters sleep mode, awaiting external wake-up.

[0045] In black-start recovery mode, when the power grid is restored or on-site operators connect a temporary maintenance power supply, the AC grid establishes a 24V base power supply through the first power conversion module. This 24V power supply is converted into control power through the black-start auxiliary power module, activating the control coil of the battery undervoltage trip protection unit and forcibly closing it. With the power supply path established on the energy storage battery side, the second power conversion module starts working, outputting 24V. The two 24V power supplies are combined through diodes to power the entire system, and the system returns to normal operation.

[0046] Under the soft start protection condition, each time the battery undervoltage trip protection unit closes, the pre-charge circuit activates first. The pre-charge resistor is connected in series in the circuit to limit the inrush current. When the input capacitor of the second power conversion module is charged to more than 95%, the bypass switch closes, and the pre-charge resistor is short-circuited, reducing losses during normal operation.

[0047] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. An intelligent power supply and energy storage system, comprising an AC power grid, an energy storage battery, and a load; characterized in that, A first power conversion module connected to the output of the AC power grid is used to convert AC power into first DC power. A black-start auxiliary power module connected to the output of the first power conversion module is used to activate the battery power supply path through the AC power grid when the energy storage battery is depleted. A battery undervoltage trip protection unit is connected to the output of the energy storage battery and the black-start auxiliary power module. A soft-start circuit is connected to the output of the battery undervoltage trip protection unit. A second power conversion module connected to the output of the soft-start circuit is used to convert high-voltage DC power into second DC power. A first anti-reverse current device is connected to the output of the first power conversion module. A second anti-reverse current device is connected to the output of the second power conversion module. A low-voltage DC bus connected to the outputs of the first and second anti-reverse current devices is used to provide working power to the load. A controllable switch array is connected to the output of the low-voltage DC bus. An intelligent control management unit, whose output is electrically connected to the AC power, the energy storage battery, the first power conversion module, the low-voltage DC bus, and the controllable switch array, is used to perform power selection, load hierarchical management, and status monitoring.

2. The intelligent power supply and energy storage system according to claim 1, characterized in that, The battery undervoltage trip protection unit includes a voltage sampling module for real-time acquisition of the energy storage battery voltage; and a controllable switch connected in series between the energy storage battery and the input terminal of the second power conversion module.

3. The intelligent power supply and energy storage system according to claim 2, characterized in that, The intelligent control management unit is preset with a first threshold and a second threshold for the battery voltage, which are used to control the on / off state of the controllable switch.

4. The intelligent power supply and energy storage system according to claim 3, characterized in that, When the battery voltage is lower than the second threshold, the intelligent control management unit controls the controllable switch to open; when the battery voltage recovers to a level higher than the first threshold, the intelligent control management unit controls the controllable switch to close.

5. The intelligent power supply and energy storage system according to claim 4, characterized in that, The load includes a critical load and a switchable load. The input terminal of the critical load is electrically connected to the output terminal of the low-voltage DC bus, and the input terminal of the switchable load is electrically connected to the output terminal of the controllable switch array.

6. The intelligent power supply and energy storage system according to claim 5, characterized in that, When the intelligent control management unit detects a power grid failure and the energy storage battery voltage is lower than the third threshold, it controls the controllable switch array to disconnect, cut off the switchable loads, and maintain power supply only to the critical loads.

7. The intelligent power supply and energy storage system according to claim 6, characterized in that, The first threshold for the energy storage battery voltage is 40% of the nominal voltage of the energy storage battery, the second threshold is 15% of the nominal voltage of the energy storage battery, and the third threshold is 25% of the nominal voltage of the energy storage battery.

8. The intelligent power supply and energy storage system according to claim 7, characterized in that, The intelligent control and management unit prioritizes the use of the first power conversion module for power supply during off-peak hours of the power grid and prioritizes the use of the second power conversion module for power supply during peak hours of the power grid.

9. The intelligent power supply and energy storage system according to claim 1, characterized in that, The soft-start circuit includes a pre-charge resistor and a bypass switch connected in parallel.

10. The intelligent power supply and energy storage system according to claim 1, characterized in that, Both the first and second anti-reverse current devices are power diodes, and their conduction direction is directed towards the low-voltage DC bus.

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