Remote inversion discharge control device for lead-acid storage battery pack

Abstract

The invention discloses a remote inversion discharge control device for a lead-acid storage battery pack, and relates to the technical field of lead-acid storage battery pack auxiliary equipment, the remote inversion discharge control device comprises a storage battery pack, a monomer acquisition unit, a storage battery remote charging and discharging device, a gateway and upper computer software, and the storage battery pack comprises two groups of 48V storage battery units. The system has the beneficial effects that an instruction is issued to the storage battery charging and discharging device through upper computer software, and the remote control device instructs charging and discharging work; the bidirectional DC / DC module in the charging and discharging device boosts the voltage of the storage battery and supplies the voltage to the actual load of the transformer substation, thereby realizing energy-saving discharging.

Description

Technical Field

[0001] The invention relates to the technical field of lead-acid battery group auxiliary equipment, in particular to a lead-acid battery group remote inverter discharge control device. Background Art

[0002] Lead-acid batteries are excellent backup energy sources and have been applied in many fields. They are widely used in power room communication systems due to their high cost-effectiveness and reusability [2]. At present, power rooms mostly use valve-regulated lead-acid batteries as backup energy sources. The batteries are required to be connected in parallel with the DC bus and immediately connected to the DC system when the AC is interrupted to ensure the stable operation of important communication equipment. Research data shows that due to the lack of active maintenance, the use of batteries as emergency energy in actual use is not optimistic. When testing the capacity of batteries that have been in use for 3 to 4 years, some batteries have a decrease in capacity and unbalanced single-cell voltage. For batteries that have been used for more than 6 years, most batteries cannot meet the design usage standards. This makes it difficult for batteries to assume the responsibility of backup energy, which has an adverse impact on the operation of the power system.

[0003] During the use of batteries, the performance inconsistency of battery cells may lead to overcharging and over-discharging during the charging and discharging process, causing battery cell failure, which in turn affects the performance of the battery pack and reduces the reliability of the battery. In addition, factors such as temperature and battery internal resistance will cause the battery to operate in an unstable state. It is very important to timely grasp the battery operation status, accurately and conveniently measure the battery capacity, and evaluate the battery performance.

[0004] According to the provisions of the "Technical Regulations for Operation and Maintenance of Battery DC Power Supply Devices for Power Systems", for batteries that are in a floating charge state for a long time, it is necessary to discharge the battery capacity to activate the battery performance, restore the effective capacity, and extend the service life. According to the requirements, the battery that has been in use for more than four years should be tested for capacity once a year. It takes more than 20 hours to discharge and charge the battery. Each power maintenance company spends a lot of manpower and material resources on the maintenance of battery capacity discharge. There are safety risks in the operation process and strict operation requirements. The maintenance cost of batteries in power rooms in remote areas is higher. At present, the battery capacity discharge mostly adopts the resistive discharge method, which consumes the battery capacity through the resistance wire. This process generates a lot of heat, wastes resources, and does not conform to the concept of environmental protection and sustainable development. In addition, the resistive discharge method requires the battery group to be completely separated from the busbar for discharge, which destroys the integrity of the backup power system of the power room. When the AC is interrupted, it is difficult to quickly access the battery group, which poses a great safety risk. Summary of the invention

[0005] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0006] Therefore, an object of the present invention is to provide a lead-acid battery pack remote inverter discharge control device, which can solve the problems mentioned in the background technology.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a lead-acid battery remote inverter discharge control device, which includes a battery pack, a monomer collection unit, a battery remote charging and discharging device, a gateway and a host computer software,

[0008] The battery pack includes two groups of 48V battery units;

[0009] The monomer collection unit is connected to the battery monomer through a signal line in the battery remote charging and discharging system, collects the battery monomer parameters and transmits them to the battery remote charging and discharging device through the signal line;

[0010] The battery remote charging and discharging device is the core of the charging and discharging system. It is controlled by STM32 single-chip microcomputer, collects the battery core capacity charging and discharging process data in real time, controls the bidirectional DC / DC conversion module to perform charging and discharging operations, and communicates with the host computer through the communication module to realize remote control of the device.

[0011] The gateway acts as a protocol conversion device to achieve the conversion between the protocol of the battery remote charging and discharging device and the protocol;

[0012] The upper computer software is a remote control terminal, which is connected to the gateway through a network port and is responsible for remotely controlling the local device to realize parameter collection, alarm and execution of charging and discharging functions.

[0013] As a preferred solution of the remote inverter discharge control device for the lead-acid battery pack described in the present invention, the remote battery charging and discharging device includes a parameter acquisition module, a seamless connection module, a bidirectional DC / DC conversion module, a switching control module, a display module, and a communication module, wherein the main control chip is electrically connected to the parameter acquisition module, the bidirectional DC / DC conversion module, the switching control module, the display module, and the communication module through a signal line, and the switching control module is electrically connected to the seamless connection module and the bidirectional DC / DC conversion module respectively. In addition, the parameter acquisition module, the bidirectional DC / DC conversion module, and the switching control module are electrically connected to the battery pack.

[0014] As a preferred solution of the lead-acid battery remote inverter discharge control device of the present invention, the parameter acquisition module uses AC voltage transmitters, Hall sensors and other devices to collect AC voltage, bus voltage, battery voltage and discharge current.

[0015] As a preferred solution of the remote inverter discharge control device for the lead-acid battery pack described in the present invention, the seamless connection module is connected to the DC bus, and the module is composed of a high-power diode and a DC contactor in parallel. The unidirectional conductivity of the diode is utilized so that when the AC power is lost, the battery does not need to be switched and the DC bus is automatically connected to achieve seamless access to the backup power supply.

[0016] As a preferred solution of the lead-acid battery remote inverter discharge control device of the present invention, the display module adopts a touch screen design, and the charging and discharging operations can be performed through the touch panel to display the nuclear capacity discharge information.

[0017] As a preferred solution of the lead-acid battery remote inverter discharge control device of the present invention, the communication module realizes the communication of the battery single cell collection unit and the communication with the gateway.

[0018] As a preferred solution of the remote inverter discharge control device for the lead-acid battery pack described in the present invention, the switching control module is composed of a control circuit, a DC bus switch, and a charge and discharge switch. A switch selection circuit and a relay drive circuit are designed. Under the control of the STM32 single-chip microcomputer, the switch switching of the charge and discharge process is realized, and the relay state feedback function is also provided.

[0019] As a preferred solution of the remote inverter discharge control device for the lead-acid battery group described in the present invention, the DC / DC module adopts a bidirectional power flow design, the input end is connected to the battery through a charge and discharge switch, and the output end is connected to the DC bus and the load. Under normal AC conditions, the battery voltage is the same as the DC bus voltage, the battery is in a floating charge state, the battery does not work on the DC load, and relies on the DC bus for energy supply to supplement the battery's own self-discharge loss.

[0020] The beneficial effects of the present invention are as follows: the present invention sends instructions to the battery charging and discharging device through the upper computer software, and the remote control device instructs the charging and discharging work; the battery voltage is increased by the bidirectional DC / DC module inside the charging and discharging device to supply the actual load of the substation, so as to realize energy-saving discharge; after the discharge is completed, the nuclear capacity battery group is charged with constant current and voltage limitation through the bidirectional DC / DC module; the battery group voltage, current, capacity, AC voltage, ambient temperature, battery cell voltage, temperature, internal resistance and other information are monitored in real time, and an alarm is issued for abnormal conditions; monitoring and charging and discharging control are carried out through a dedicated transmission network, compatible standards, charging and discharging data are analyzed, and battery performance is estimated. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0026] Example 1

[0027] Reference Figure 1 , which is the first embodiment of the present invention, and provides a lead-acid battery remote inverter discharge control device, which includes a battery pack, a single cell acquisition unit, a battery remote charge and discharge device, a gateway and a host computer software,

[0028] The battery pack contains two groups of 48V battery units;

[0029] The single cell acquisition unit is connected to the battery single cell through a signal line in the battery remote charging and discharging system, collects the battery single cell parameters and transmits them to the battery remote charging and discharging device through the signal line;

[0030] The battery remote charging and discharging device is the core of the charging and discharging system. It is controlled by STM32 single-chip microcomputer, collects the battery core capacity charging and discharging process data in real time, controls the bidirectional DC / DC conversion module to perform charging and discharging operations, and communicates with the host computer through the communication module to realize remote control of the device.

[0031] The gateway is used as a protocol conversion device to realize the conversion between the battery remote charging and discharging device protocol and protocol;

[0032] The upper computer software is the remote control terminal, which is connected to the gateway through the network port and is responsible for remotely controlling the local device to realize parameter collection, alarm and execution of charging and discharging functions.

[0033] The resistive discharge method consumes the battery capacity through the resistance wire, resulting in energy waste; the battery pack needs to be completely separated from the busbar to discharge, which destroys the integrity of the backup power supply system; manual on-site operation causes high maintenance costs and safety risks; the lack of real-time monitoring of single-cell parameters makes it difficult to detect abnormal conditions in time. The present invention uses a bidirectional DC / DC conversion module to directly supply the battery discharge energy to the substation load, avoiding energy waste in the form of heat; the seamless connection module design of high-power diodes and DC contactors in parallel allows the battery to automatically connect to the DC busbar without switching when the AC power is lost, ensuring the integrity and reliability of the backup power supply system; the remote charging and discharging device based on the STM32 single-chip microcomputer control, in conjunction with the gateway and the host computer software, realizes remote control and monitoring of the charging and discharging process, significantly reducing maintenance costs and operational risks; the single-cell acquisition unit collects the battery single-cell voltage, temperature, internal resistance and other parameters in real time and has an abnormal condition alarm function, effectively preventing the battery from being overcharged or over-discharged. At the same time, the device also realizes constant current and voltage-limited charging of the battery pack through a bidirectional DC / DC module, extending the service life of the battery. The device provides a cost-effective solution for remote maintenance of lead-acid battery packs, with significant advantages such as energy saving and environmental protection, system reliability, and convenient maintenance.

[0034] Furthermore, the battery remote charging and discharging device includes a parameter acquisition module, a seamless connection module, a bidirectional DC / DC conversion module, a switching control module, a display module, and a communication module, wherein the main control chip is electrically connected to the parameter acquisition module, the bidirectional DC / DC conversion module, the switching control module, the display module, and the communication module through a signal line, and the switching control module is electrically connected to the seamless connection module and the bidirectional DC / DC conversion module respectively; in addition, the parameter acquisition module, the bidirectional DC / DC conversion module, and the switching control module are electrically connected to the battery pack.

[0035] The invention mainly solves the technical problems of low integration, dispersed functions and poor coordination between modules of existing battery maintenance equipment. Existing equipment often requires the cooperation of multiple independent devices to complete the charging and discharging maintenance work, which not only increases the complexity of the system, but also easily affects the maintenance effect due to communication and coordination problems between devices. The present invention integrates the parameter acquisition module, seamless connection module, bidirectional DC / DC conversion module, switching control module, display module and communication module into the same device, and adopts the main control chip for unified scheduling and control, so as to achieve high integration of the system. The parameter acquisition module is responsible for real-time monitoring of key parameters such as voltage and current, the seamless connection module ensures safe switching of the system, the bidirectional DC / DC conversion module performs charging and discharging energy conversion, the switching control module coordinates the working status of each module, the display module provides a human-computer interaction interface, and the communication module realizes remote data transmission. Each module is electrically connected to the main control chip through a signal line to form a unified control system. This modular and integrated design not only reduces the complexity of the system and improves the reliability of the device, but also enhances the precise control of the charging and discharging process through the coordination between modules, making the battery maintenance work more efficient and safe. In particular, the switching control module achieves smooth switching of the battery pack during the charging and discharging process by cooperating with the seamless connection module and the bidirectional DC / DC conversion module, avoiding the switching shock problem caused by the dispersion of modules in traditional equipment.

[0036] Furthermore, the parameter acquisition module uses devices such as AC voltage transmitters and Hall sensors to collect AC voltage, bus voltage, battery pack voltage and discharge current.

[0037] The invention mainly solves the technical problems of low parameter acquisition accuracy and limited acquisition range of existing battery monitoring equipment. Traditional battery monitoring equipment can only collect some parameters, and the sampling accuracy is insufficient, which cannot fully reflect the operating status of the battery pack. The present invention adopts an AC voltage transmitter to collect AC voltage, and uses a Hall sensor to collect bus voltage, battery pack voltage and discharge current, forming a complete parameter acquisition system. Among them, the AC voltage transmitter has the characteristics of strong anti-interference ability and high isolation, which ensures the accuracy of AC voltage sampling; the Hall sensor adopts a non-contact measurement principle, has the advantages of fast response speed, wide measurement range, high accuracy, etc., and can monitor multiple voltage and current signals at the same time. This diversified parameter acquisition scheme enables the device to fully grasp the operating status of the battery pack and provide accurate data support for charge and discharge control. In particular, during the nuclear capacity discharge process, by real-time monitoring of discharge current and voltage changes, the battery capacity can be accurately evaluated and abnormal conditions can be discovered in time. Compared with the traditional single parameter acquisition method, the parameter acquisition scheme provided by the present invention has the advantages of high acquisition accuracy, comprehensive monitoring and strong reliability, which provides a strong guarantee for the safe operation of the battery pack.

[0038] Furthermore, a seamless connection module is connected to the DC bus. The module is composed of a high-power diode and a DC contactor in parallel. The unidirectional conductivity of the diode is utilized so that when the AC power fails, the battery does not need to be switched and the DC bus is automatically connected to achieve seamless access to the backup power supply.

[0039] The invention mainly solves the technical problems of the existing battery backup power supply system in that the switching response is slow and the power supply is easily interrupted when the AC power is cut off. The traditional system usually relies on mechanical switches for switching, which not only has mechanical action delay, but also may cause switching failure due to contactor failure. The seamless connection module of the present invention cleverly utilizes the unidirectional conductive characteristics of the diode through the innovative design of connecting a high-power diode in parallel with a DC contactor. When the AC power supply is normal, the battery pack is connected in parallel with the busbar through a DC contactor to achieve floating charge; when the AC power is lost, even if the DC contactor does not act in time, the diode can be turned on immediately, so that the battery pack is automatically connected to the DC busbar to achieve instantaneous switching of the backup power supply. This circuit structure design eliminates the time delay in the switching process of the mechanical switch, avoids voltage fluctuations during the switching process, and ensures continuous power supply to critical loads. At the same time, the parallel configuration of the diode and the DC contactor also provides double protection: even if one of the components fails, the other component can still ensure the normal operation of the system, significantly improving the reliability of the backup power supply system. The design of this module not only solves the technical defects in the traditional switching method, but also realizes seamless power switching through a simple and reliable circuit structure, providing a strong guarantee for the continuous and stable operation of the power room.

[0040] Furthermore, the display module adopts a touch screen design, and the charging and discharging operations can be performed through the touch panel to display the core capacity discharge information.

[0041] The invention mainly solves the technical problems of the existing battery maintenance equipment, such as the complicated operation, the non-intuitive information display and the low efficiency of human-computer interaction. Traditional equipment mostly adopts the mode of key plus digital tube display, which has cumbersome operation steps and can only display limited digital information, and it is difficult to meet the complex core capacity discharge operation requirements. The present invention adopts a display module designed with a touch screen to integrate the charge and discharge operation instructions and the core capacity discharge information in the same display interface. The graphical interface of the touch screen intuitively displays the core capacity discharge parameters such as voltage, current, and capacity. The operator can complete the charge and discharge parameter setting, start and stop control and other operations through the touch panel without memorizing complex key combinations. This design method not only simplifies the operation process and reduces the difficulty of operation, but also can display key information such as charge and discharge curves and remaining capacity in real time, so that the operator can more accurately judge the working status of the battery pack. At the same time, the multi-page display function of the touch screen also supports extended applications such as historical data query and alarm information display, providing comprehensive information support for the maintenance and management of the battery pack. The design of the display module not only improves the work efficiency of daily maintenance, but also reduces the skill requirements of the operator, making the maintenance and management of the battery pack more convenient and efficient.

[0042] Furthermore, the communication module realizes the communication of the battery cell collection unit and the communication with the gateway.

[0043] The invention mainly solves the technical problems of decentralized data collection, non-uniform communication protocols and low information transmission efficiency in the existing battery management system. In the traditional system, independent communication modules are often used for battery cell data collection and remote communication, which not only increases the complexity of the system, but also easily causes data transmission delay or loss due to protocol conversion problems. The communication module of the present invention adopts a unified design, and simultaneously undertakes the data communication of the battery cell collection unit and the remote communication function with the gateway. In terms of single cell data collection, the communication module establishes a reliable connection with the collection unit through a specific communication protocol to obtain parameters such as voltage and temperature in real time; in terms of remote communication, a stable data transmission channel is established between the module and the gateway to ensure the timely transmission of charge and discharge control instructions and monitoring data. This integrated communication solution not only simplifies the system structure and reduces communication delay, but also improves the reliability of information transmission through a unified data processing mechanism. The design of the communication module breaks through the limitations of the traditional decentralized communication mode, realizes end-to-end communication from single cell data collection to remote control, and provides a reliable data channel for the intelligent remote management of battery packs.

[0044] Furthermore, the switching control module is composed of a control circuit, a DC bus switch, and a charging and discharging switch. The switch selection circuit and the relay drive circuit are designed. Under the control of the STM32 microcontroller, the switch switching of the charging and discharging process is realized, and at the same time, it has the relay state feedback function.

[0045] The invention mainly solves the technical problems of inaccurate switching control and lack of feedback mechanism in the charging and discharging process of the existing battery maintenance equipment. Traditional equipment often adopts simple switch control, lacks state feedback and precise control capabilities, and easily leads to electrical shocks during the switching process. The switching control module of the present invention adopts a control circuit to cooperate with the DC bus switch and the charging and discharging switch, and realizes precise control through the switch selection circuit and the relay drive circuit. The STM32 single-chip microcomputer controls the switch switching process in real time, and the relay state feedback mechanism reports the switch state in time to provide a basis for fault diagnosis. This design improves the system reliability through state feedback while ensuring the smooth switching of the charging and discharging process, making the charging and discharging process safer and more controllable. Compared with the traditional unidirectional switching control, the module not only improves the switching accuracy through the bidirectional feedback mechanism, but also enhances the fault diagnosis and processing capabilities of the system, providing a more reliable guarantee for the safe operation of the battery pack.

[0046] Furthermore, the DC / DC module adopts a bidirectional power flow design. The input end is connected to the battery through a charge and discharge switch, and the output end is connected to the DC bus and the load. Under normal AC conditions, the battery voltage is the same as the DC bus voltage, and the battery is in a floating charge state. The battery has no effect on the DC load and relies on the DC bus for energy to supplement the battery's own self-discharge loss.

[0047] The technical problem that the battery pack in the existing battery charging and discharging device cannot meet the dual needs of maintenance discharge and emergency power supply at the same time is solved. By adopting a two-way power flow design, the battery is kept in a floating charge state during normal operation, and only the self-discharge loss is supplemented. The battery voltage is equal to the DC bus voltage and does not affect the load power supply; during maintenance discharge, the battery is connected to the battery through the charging and discharging switch, and the battery power is fed back to the DC bus and the load, which not only avoids the energy waste of the traditional resistance discharge method, but also ensures the continuity of the system power supply, and realizes the compatible operation of battery maintenance and emergency power supply. This solution overcomes the defects of traditional resistance discharge that the battery pack needs to be completely separated from the bus, the energy loss is large, and the emergency power supply cannot be guaranteed, and embodies the technical effects of energy saving, environmental protection, safety and reliability.

[0048] In summary, the present invention sends instructions to the battery charging and discharging device through the upper computer software, and the remote control device instructs the charging and discharging work; the battery voltage is increased by the bidirectional DC / DC module inside the charging and discharging device to supply the actual load of the substation, so as to realize energy-saving discharge; after the discharge is completed, the nuclear capacity battery group is charged with constant current and voltage limiting through the bidirectional DC / DC module; the battery group voltage, current, capacity, AC voltage, ambient temperature, battery cell voltage, temperature, internal resistance and other information are monitored in real time, and an alarm is issued for abnormal conditions; monitoring and charging and discharging control are carried out through a dedicated transmission network, compatible standards, charging and discharging data are analyzed, and battery performance is estimated.

[0049] It is important to note that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A lead-acid battery remote inverter discharge control device, characterized in that: include, Battery pack, single cell acquisition unit, battery remote charging and discharging device, gateway and host computer software, The battery pack includes two groups of 48V battery units; The monomer collection unit is connected to the battery monomer through a signal line in the battery remote charging and discharging system, collects the battery monomer parameters and transmits them to the battery remote charging and discharging device through the signal line; The battery remote charging and discharging device is the core of the charging and discharging system. It is controlled by STM32 single-chip microcomputer, collects the battery core capacity charging and discharging process data in real time, controls the bidirectional DC / DC conversion module to perform charging and discharging operations, and communicates with the host computer through the communication module to realize remote control of the device. The gateway acts as a protocol conversion device to achieve conversion between the battery remote charging and discharging device protocol and protocol; The upper computer software is a remote control terminal, which is connected to the gateway through a network port and is responsible for remotely controlling the local device to realize parameter collection, alarm and execution of charging and discharging functions.

2. The lead-acid battery remote inverter discharge control device according to claim 1, characterized in that: The battery remote charging and discharging device includes a parameter acquisition module, a seamless connection module, a bidirectional DC / DC conversion module, a switching control module, a display module, and a communication module, wherein the main control chip is electrically connected to the parameter acquisition module, the bidirectional DC / DC conversion module, the switching control module, the display module, and the communication module through a signal line, and the switching control module is electrically connected to the seamless connection module and the bidirectional DC / DC conversion module respectively. In addition, the parameter acquisition module, the bidirectional DC / DC conversion module, and the switching control module are electrically connected to the battery pack.

3. The lead-acid battery remote inverter discharge control device according to claim 2, characterized in that: The parameter acquisition module uses devices such as an AC voltage transmitter and a Hall sensor to collect the AC voltage, bus voltage, battery pack voltage and discharge current.

4. The lead-acid battery remote inverter discharge control device according to claim 3, characterized in that: The seamless connection module is connected to the DC bus. The module is composed of a high-power diode and a DC contactor in parallel. The unidirectional conductivity of the diode is used to automatically connect the DC bus without switching the battery when the AC power is lost, thereby realizing seamless access to the backup power supply.

5. The lead-acid battery remote inverter discharge control device according to claim 4, characterized in that: The display module adopts a touch screen design, and can perform charging and discharging operations through the touch panel to display nuclear capacity discharge information.

6. The lead-acid battery remote inverter discharge control device according to claim 5, characterized in that: The communication module realizes the communication of the battery single body collection unit and the communication with the gateway.

7. The lead-acid battery remote inverter discharge control device according to claim 6, characterized in that: The switching control module is composed of a control circuit, a DC bus switch, and a charge and discharge switch. A switch selection circuit and a relay drive circuit are designed. Under the control of an STM32 single-chip microcomputer, the switch switching of the charge and discharge process is realized, and the relay state feedback function is also provided.

8. The lead-acid battery remote inverter discharge control device according to claim 7, characterized in that: The DC / DC module adopts a bidirectional power flow design. The input end is connected to the battery through a charge and discharge switch, and the output end is connected to the DC bus and the load. Under normal AC conditions, the battery voltage is the same as the DC bus voltage, and the battery is in a floating charge state. The battery has no effect on the DC load and relies on the DC bus for energy supply to supplement the battery's own self-discharge loss.

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