Single-phase energy storage power supply, control method and capacity expansion device based on single-phase energy storage power supply

Abstract

The application belongs to the technical field of power supply control, and particularly relates to a single-phase energy storage power supply, a control method and an expansion device based on the single-phase energy storage power supply. The single-phase energy storage power supply comprises a switch assembly configured to form at least one of a charging branch, a discharging branch and a bypass branch in response to a switch control signal; a power supply assembly configured to receive electric energy from the AC input port through the charging branch for charging or provide electric energy to the AC output port through the discharging branch in response to a power supply control signal; and a master control unit configured to detect a level state of the communication input interface and a voltage state of the AC input port, and generate the switch control signal and the power supply control signal based on the level state and the voltage state. The application realizes intelligent series expansion of multiple power supplies through cooperative judgment of the communication level and the voltage state, and solves the problems of limited expansion capacity and inconvenience in carrying in the prior art.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power supply control, and particularly relates to a single-phase energy storage power supply, a control method and an expansion device based on the single-phase energy storage power supply. BACKGROUND

[0002] With the increasing demand for power in outdoor power supply, emergency power supply and other scenarios, the capacity of a single single-phase energy storage power supply is often difficult to meet the use requirements, and an efficient and convenient multi-machine expansion solution is urgently needed.

[0003] At present, the related technology usually adopts an external expansion box to realize expansion. This scheme connects the outputs of multiple power supplies to the expansion box, and controls the switching power supply by the relay in the box. However, this scheme has obvious limitations: first, the expansion capacity is limited by the number of physical interfaces of the expansion box, and usually only supports 3-4 devices to be connected, and cannot realize flexible and large-scale capacity expansion; second, the expansion box as an independent component not only increases the system cost, but also significantly reduces the portability of the entire system due to its additional volume and weight.

[0004] Therefore, how to improve the expansion capacity while enhancing the portability of the expansion device has become a technical problem to be solved at present. SUMMARY

[0005] The application provides a single-phase energy storage power supply, a control method and an expansion device based on the single-phase energy storage power supply, which solves the problems of limited expansion capacity and inconvenience of carrying in the power supply expansion of the related technology.

[0006] In a first aspect, the application provides a single-phase energy storage power supply, which comprises: a switch assembly, a first end of the switch assembly serving as an AC input port of the single-phase energy storage power supply, a second end of the switch assembly serving as an AC output port of the single-phase energy storage power supply, the switch assembly being configured to form at least one of a charging branch, a discharging branch and a bypass branch inside in response to a switch control signal; a power supply assembly connected to a third end of the switch assembly, the power supply assembly being configured to receive electric energy from the AC input port for charging through the charging branch or provide electric energy to the AC output port through the discharging branch in response to a power supply control signal; a master control unit having a communication input interface and a communication output interface, the master control unit being connected to a controlled end of the switch assembly and a controlled end of the power supply assembly respectively; the master control unit is configured to detect the level state of the communication input interface and the voltage state of the AC input port, and generate the switch control signal and the power supply control signal based on the level state and the voltage state; and control the level state of the communication output interface according to the current working mode of the single-phase energy storage power supply.

[0007] In a second aspect, the application provides a capacity expansion device based on single-phase energy storage power supplies, the capacity expansion device comprising: M single-phase energy storage power supplies, M being an integer greater than 1; an AC input port of a first single-phase energy storage power supply is configured to be connected to an external power grid, an AC output port of an mth single-phase energy storage power supply is connected to an AC input port of an (m+1)th single-phase energy storage power supply through a power supply line; an AC output port of an Mth single-phase energy storage power supply is configured to be connected to an external load; a communication output interface of the mth single-phase energy storage power supply is connected to a communication input interface of the (m+1)th single-phase energy storage power supply through a communication line; wherein m = [1, …, M-1].

[0008] In a third aspect, the application provides a control method of a single-phase energy storage power supply, applied to a single-phase energy storage power supply, the control method comprising: detecting a level state of a communication input interface and a voltage state of an AC input port; generating a switch control signal and a power supply control signal based on the level state and the voltage state, so that a switch assembly is switched between a discharge branch, a bypass branch and a charging branch according to the switch control signal, and a power supply assembly is charged or discharged under the action of the power supply control signal and the switch assembly.

[0009] The technical scheme provided by the application has at least the following beneficial effects:

[0010] (1) The application detects the level state of the communication input interface and the voltage state of the AC input port through the master control unit, and generates the switch control signal and the power supply control signal based thereon, to control the switch assembly to switch to the corresponding branch and manage the charging and discharging state of the power supply assembly, thereby achieving accurate identification and automatic control of the series bypass mode and the grid charging mode, so that when multiple power supplies are connected in series, the rear power supply works in a pure bypass state without charging, and the problem of efficiency loss caused by multiple energy transfers between power supplies in the traditional bypass capacity expansion scheme is solved.

[0011] (2) The application achieves the cooperative logic and information transmission of front-stage priority discharge when multiple power supplies are connected in series by setting the communication input and output interfaces and controlling the level state of the communication output interface by the master control unit according to the working mode of the master control unit, so as to achieve the effect that only the first power supply needs to switch modes, and the relays of the rear power supplies remain in the original state, thereby solving the problems of system instability, high noise and reduced device life caused by frequent and disordered switching of multiple power supply relays due to input power failure in the traditional scheme.

[0012] (3) This application integrates the communication and control functions required for capacity expansion into a single power supply, eliminating the need for external dedicated capacity expansion control equipment (such as a capacity expansion box). This achieves the system's extremely simple serial connection and plug-and-play functionality, theoretically enabling unlimited capacity expansion, significantly reducing costs and improving portability. This solves the problems of limited capacity expansion capability, high cost, inconvenience in carrying, and cumbersome charging operation associated with external capacity expansion box solutions. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0014] Figure 1 The diagram shown is a structural schematic of an external expansion box in related technologies.

[0015] Figure 2 The diagram shown is a schematic diagram of a series expansion structure provided in an embodiment of this application.

[0016] Figure 3 The diagram shown is a structural schematic of the first single-phase energy storage power supply provided in the embodiment of this application.

[0017] Figure 4 The diagram shown is a structural schematic of the second single-phase energy storage power supply provided in an embodiment of this application.

[0018] Figure 5 The diagram shown is a structural schematic of the third single-phase energy storage power supply provided in the embodiment of this application.

[0019] Figure 6 The diagram shown is a structural schematic of a capacity expansion device based on a single-phase energy storage power supply provided in an embodiment of this application.

[0020] Figure 7 The diagram shown is a flowchart illustrating a control method for a single-phase energy storage power supply provided in an embodiment of this application.

[0021] Figure 8 The diagram shown is a flowchart illustrating the working mode identification process of a single-phase energy storage power supply according to an embodiment of this application.

[0022] Figure 9 The diagram shown is a control logic schematic of a communication output interface provided in an embodiment of this application.

[0023] Explanation of reference numerals in the attached figures:

[0024] 10. Capacity expansion device based on single-phase energy storage power supply;

[0025] 100. Single-phase energy storage power supply; 110. Switching assembly; 120. Power supply assembly; 130. Main control unit; 131. Level detection circuit; 132. Voltage detection circuit; 133. Controller; 134. Level control circuit;

[0026] K1, Bypass relay; K2, Charging relay; K3, Discharging relay; L1, Charging inductor; L2, Discharging inductor; F1, First fuse; F2, Second fuse; CM1, Common mode inductor. Detailed Implementation

[0027] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0028] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0029] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present application, and should not be construed as limiting the present application.

[0030] Single-phase energy storage power supplies have relatively small capacities, and their discharge capacity may not meet usage requirements, often necessitating expansion through parallel or series connection of multiple devices. A typical solution in related technologies is to use an external expansion box, such as... Figure 1 As shown, this solution connects the outputs of multiple power supplies to an expansion box, with relays inside the box controlling the switching to determine which power supply outputs to the load. When one power supply fails or runs out of power, the expansion box switches to another power supply to ensure continuous power supply. However, this expansion box solution has limitations: firstly, its expansion capacity is limited by the number of physical interfaces in the box, typically supporting only 3-4 devices; secondly, the additional expansion equipment increases system cost and size; and finally, charging requires unplugging each power supply from the box and connecting it individually to the power grid, which is cumbersome.

[0031] To address the aforementioned problems, the inventors of this application conceived of a series connection scheme that does not rely on external devices, namely, utilizing a power supply with EPS (Emergency Power Supply) / UPS (Uninterruptible Power Supply) functionality for multi-stage bypass expansion, such as... Figure 2 As shown, although this preliminary solution eliminates the need for an expansion box, it has other drawbacks: First, in series bypass mode, the front-end power supply will incorrectly charge the battery of the rear-end power supply, and the energy will undergo multiple "DC-AC inversion → AC-DC rectification" transfer processes, resulting in a significant reduction in system efficiency and a decrease in the actual capacity supplied to the load; Second, the system has poor reliability. When the front-end power supply shuts down for some reason, each of the rear-end power supplies will enter the discharge mode successively due to abnormal input voltage, and then try to switch back to bypass mode when it detects that the front-end has resumed power supply, causing the relays in the system to repeatedly and disorderly open and close. The number of switching increases geometrically with the number of power supplies, which seriously affects the user experience and equipment lifespan.

[0032] To address the problems in the aforementioned related technologies, the inventors of this application have, after research, provided a single-phase energy storage power supply, specifically including the following embodiments:

[0033] Figure 3 The diagram shown is a structural schematic of the first single-phase energy storage power supply 100 provided in an embodiment of this application; as shown Figure 3 As shown, the single-phase energy storage power supply 100 in this embodiment includes a switching assembly 110, a power supply assembly 120, and a main control unit 130.

[0034] Specifically, the first end of the switching assembly 110 serves as the AC input port of the single-phase energy storage power supply 100, and the second end of the switching assembly 110 serves as the AC output port of the single-phase energy storage power supply 100. The switching assembly 110 is configured to respond to a switching control signal and internally form at least one of a charging branch, a discharging branch, and a bypass branch.

[0035] It should be noted that the switching component 110 in this embodiment mainly controls the flow of AC power inside the power supply. Specifically, the first end of the switching component 110 is defined as the AC input port, which is used to connect to the power grid or the upstream power supply; the second end of the switching component 110 is defined as the AC output port, which is used to connect to the load or the downstream power supply; and the third end of the switching component 110 is used to connect to the internal power supply component 120. The switching component 110 in this embodiment receives the switching control signal from the main control unit 130 and dynamically constructs different current paths by combining and switching internal relays, semiconductor switches and other components. Specifically, three basic branches can be formed: (1) Charging branch: connecting the AC input port to the power supply component 120, allowing external power to charge the power supply component 120; (2) Discharging branch: connecting the power supply component 120 to the AC output port, allowing the power supply component 120 to invert and discharge to drive the load; (3) Bypass branch: directly connecting the AC input port to the AC output port, so that the power is transmitted directly to the downstream without passing through the power supply component 120. This embodiment provides a flexible and reliable power routing mechanism through the switch assembly 110, which is the physical basis for realizing multiple working modes.

[0036] In this embodiment, the power supply component 120 is connected to the third terminal of the switch component 110. The power supply component 120 is configured to receive electrical energy from the AC input port through the charging branch for charging in response to a power control signal, or to provide electrical energy to the AC output port through the discharging branch.

[0037] It should be noted that the power supply component 120 in this embodiment is an energy storage and release unit, typically including a battery pack (such as a lithium-ion battery) and a charge / discharge management circuit (such as a bidirectional DC-AC converter) connected to it; the power supply component 120 responds to the power control signal issued by the main control unit 130. When the signal indicates charging, it receives and stores energy through the established charging branch; when the signal indicates discharging, it inverts the stored DC power into AC power through the established discharging branch and outputs it, thereby achieving efficient energy storage and on-demand release, and intelligently responding to the system's charge / discharge commands.

[0038] In this embodiment, the main control unit 130 has a communication input interface and a communication output interface. The main control unit 130 is connected to the controlled terminal of the switch assembly 110 and the controlled terminal of the power supply assembly 120, respectively. The main control unit 130 is configured to: detect the level state of the communication input interface and the voltage state of the AC input port, and generate a switch control signal and a power supply control signal based on the level state and the voltage state; and control the level state of the communication output interface according to the current working mode of the single-phase energy storage power supply 100.

[0039] It should be noted that the main control unit 130 has a communication input interface and a communication output interface, and is connected to the switch assembly 110 and the power supply assembly 120 via control lines. The main working process of the main control unit 130 includes:

[0040] (1) Continuously detect the level status (high level or low level) of the communication input interface and the voltage status (whether there is voltage or whether it is within the normal range) of the AC input port.

[0041] (2) Based on different combinations of logic for level and voltage states, switch control signals and power control signals are generated. For example, if a high level is detected in the communication input, the switch component 110 is controlled to form a bypass branch, and the power component 120 is controlled to stop charging.

[0042] (3) Control the level state of the communication output interface according to the determined current working mode. For example, when it is in discharge mode or expansion bypass mode, it outputs a high level; when it is in grid charging mode, it outputs a low level.

[0043] In summary, the specific working principle of the single-phase energy storage power supply 100 in this embodiment is as follows: the main control unit 130 performs coordinated detection and logical judgment on the level status of the communication input interface and the voltage status of the AC input port to identify the current working mode of the power supply, such as the discharge mode, series bypass mode or grid charging mode; based on the identification result, the main control unit 130 simultaneously issues three sets of instructions: (1) controls the switch assembly 110 to switch to the corresponding branch combination; (2) controls the power supply assembly 120 to execute the charging, discharging or idle instructions; (3) controls the communication output interface to output the corresponding level signal to inform the downstream equipment of its own status.

[0044] In summary, the single-phase energy storage power supply 100 provided in this application has at least the following beneficial effects:

[0045] (1) This application detects the level state of the communication input interface and the voltage state of the AC input port through the main control unit 130, and generates switch control signal and power control signal based on this to control the switch component 110 to switch to the corresponding branch and manage the charging and discharging state of the power component 120. This achieves accurate identification and automatic control of the series bypass mode and the grid charging mode, so that when multiple power supplies are connected in series for expansion, the downstream power supply works in a pure bypass state and does not charge, thus solving the efficiency loss problem caused by multiple energy transfers between power supplies in the traditional bypass expansion scheme.

[0046] (2) By setting up communication input and output interfaces and enabling the main control unit 130 to control the level state of the communication output interface according to its own working mode, this application realizes the collaborative logic and information transmission of the priority discharge of the front stage when multiple power supplies are connected in series, so that only the first power supply needs to switch modes and the power relays of the subsequent stage maintain the original state. This solves the problems of system instability, high noise and reduced device life caused by the frequent and disorderly switching of multiple power relays due to the input power failure in the traditional solution.

[0047] (3) This application integrates the communication and control functions required for capacity expansion into a single power supply, eliminating the need for external dedicated capacity expansion control equipment (such as a capacity expansion box). This achieves the system's extremely simple serial connection and plug-and-play functionality, theoretically enabling unlimited capacity expansion, significantly reducing costs and improving portability. This solves the problems of limited capacity expansion capability, high cost, inconvenience in carrying, and cumbersome charging operation associated with external capacity expansion box solutions.

[0048] Figure 4 The diagram shown is a structural schematic of the second single-phase energy storage power supply 100 provided in an embodiment of this application; as shown Figure 4 As shown, the switching assembly 110 of this embodiment includes a bypass relay K1, a charging relay K2, and a discharging relay K3. Specifically, the first connection terminal of the bypass relay K1 serves as the first terminal of the switching assembly 110, the second connection terminal of the bypass relay K1 serves as the second terminal of the switching assembly 110, and the control terminal of the bypass relay K1 is connected to the main control unit 130. The bypass relay K1 is used to form a bypass branch. The first connection terminal of the charging relay K2 is connected to the first connection terminal of the bypass relay K1, the second connection terminal of the charging relay K2 serves as the third terminal of the switching assembly 110, and the control terminal of the charging relay K2 is connected to the main control unit 130. The charging relay K2 is used to form a charging branch. The first connection terminal of the discharging relay K3 is connected to the second connection terminal of the bypass relay K1, the second connection terminal of the discharging relay K3 is connected to the second connection terminal of the charging relay K2, and the control terminal of the discharging relay K3 is connected to the main control unit 130. The discharging relay K3 is used to form a discharging branch.

[0049] It should be noted that in this embodiment, the bypass relay K1 constitutes the actuator of the bypass branch. When the control terminal of the bypass relay K1 receives a closing command from the main control unit 130, its contacts close, thereby physically connecting the AC input port and the AC output port directly to form the bypass branch. At this time, the current bypasses the internal charging and discharging circuits and is directly transmitted to the downstream load or equipment, thereby realizing the direct and lossless transmission of electrical energy. This is the basis for the bypass function in the series bypass mode and the grid charging mode, with fast response speed and low conduction loss.

[0050] In this embodiment, the charging relay K2 is the actuator constituting the charging branch. Its first connection terminal is connected to the first connection terminal (i.e., the AC input port) of the bypass relay K1, and its second connection terminal serves as the third terminal of the switching assembly 110, connected to the internal power supply assembly 120. When its control terminal receives a closing command from the main control unit 130, its contacts close, guiding the electrical energy from the AC input port to the power supply assembly 120, forming the charging branch. The charging relay K2 and the bypass relay K1 work together, and in the grid charging mode, they are simultaneously connected with the bypass branch, realizing simultaneous power supply and charging of the load. Under the control of the main control unit 130, it can reliably disconnect in the series bypass mode, ensuring that the downstream power supply does not charge, thereby avoiding energy transfer.

[0051] In this embodiment, the discharge relay K3 is the actuator that constitutes the discharge branch. Its first connection terminal is connected to the second connection terminal (i.e., the AC output port) of the bypass relay K1, and its second connection terminal is connected to the second connection terminal (i.e., the third terminal of the switch assembly 110, which is connected to the power supply assembly 120) of the charging relay K2. When its control terminal receives a closing command from the main control unit 130 (while the charging relay K2 is opened), its contacts close, guiding the AC power generated by the power supply assembly 120 after inversion to the AC output port, forming a discharge branch, thereby realizing the energy output of the power supply assembly 120. In addition, the interlocking relationship between the discharge relay K3 and the charging relay K2 (usually not closing at the same time) is guaranteed by the logic of the main control unit 130, preventing current backflow and ensuring system safety.

[0052] It should be further explained that the bypass relay K1, charging relay K2, and discharging relay K3 in this embodiment constitute a switching network of three branches; the main control unit 130 can construct three basic branches by independently controlling the on / off combinations of the three relays, specifically: (1) closing the bypass relay K1 and opening the charging relay K2 and discharging relay K3 to form a bypass branch. (2) closing the charging relay K2 and bypass relay K1 and opening the discharging relay K3 to form a bypass branch and a charging branch. (3) closing the discharging relay K3 and opening the other two to form a discharging branch.

[0053] Therefore, by employing a specific topology connection of three relays, a simple, low-cost, and reliable switching network is constructed, providing an optimal hardware foundation for realizing three basic working branches. Optionally, by directly bridging the bypass relay K1 between the AC input and output ports, direct and low-loss transmission of AC power is achieved, laying a structural foundation for improving the overall efficiency of the system in series bypass and grid charging modes. Optionally, by sharing the same port of the power supply component 120 with the charging relay K2 and the discharging relay K3, the internal circuit structure is simplified, and the centralized control of the main control unit 130 ensures the physical mutual exclusion of the charging and discharging paths, fundamentally improving the safety and reliability of the system.

[0054] In one embodiment, the switching assembly 110 further includes a charging inductor L1, connected in series on the live wire between the second connection terminal of the charging relay K2 and the power supply assembly 120, such as... Figure 4 As shown, during the charging process, when the charging relay K2 is closed, current flows through the charging inductor L1. The inductor suppresses sudden changes in current, causing the input current waveform to follow the changes in the input voltage waveform. The main function of the charging inductor L1 in this embodiment is to improve the power factor of the entire charging circuit, reduce harmonic pollution to the power grid, make the charging process more compliant with power grid specifications, and also suppress switching noise and improve electromagnetic compatibility performance.

[0055] In one embodiment, the switching assembly 110 further includes a discharge inductor L2, connected in series on the live wire between the first connection terminal of the discharge relay K3 and the power supply assembly 120, such as... Figure 4 As shown: During the discharge process, when the discharge relay K3 is closed, the high-frequency PWM (pulse width modulation) AC power generated by the inverter passes through the discharge inductor L2. Its main function is to filter out the high-frequency switching carrier component in the inverter output signal, smooth the output current, and make the final output to the AC port a pure, low-distortion sine wave AC power. This effectively reduces the total harmonic distortion of the output voltage, ensures high-quality power for the load, and reduces potential interference to the load.

[0056] In one embodiment, the switch assembly 110 further includes a first fuse F1, connected in series on the live wire between the AC input port and the first connection terminal of the charging relay K2; as Figure 4 As shown, the first fuse F1 serves as an overcurrent protection device for the AC input circuit. When the input circuit generates an excessive current far exceeding the rated value due to an internal short circuit (such as the breakdown of the charging relay K2 or a PFC circuit failure) or an external abnormality (such as a power grid surge), the fuse will quickly melt due to overheating. By physically cutting off the electrical connection of the input live wire, it prevents the fault from spreading and protects the front-end power grid connection point and related circuits on the AC input side of the power supply from damage caused by continuous overcurrent, providing the most basic and reliable safety barrier.

[0057] In one embodiment, the switch assembly 110 further includes a second fuse F2, connected in series on the live wire between the second connection terminal of the discharge relay K3 and the AC output port; as Figure 4 As shown, the second fuse F2 serves as an overcurrent protection device for the AC output circuit. When a large current is generated at the output port due to a short circuit in the connected load or a fault in the inverter itself, the fuse will blow to prevent the fault current from causing permanent damage to the inverter power devices, output relays, etc., while ensuring the safety of the external load connected to the output terminal and the downstream equipment.

[0058] In one embodiment, the switching assembly 110 further includes a common-mode inductor CM1, connected in series between the second connection terminal of the discharge relay K3 and the AC output port; as Figure 4 As shown, for the differential mode current (flowing out of the live wire and returning to the neutral wire) during normal operation, the magnetic fields generated by the current cancel each other out, and the common mode inductor CM1 exhibits low impedance. However, for the common mode noise current generated by the high-speed switching of the switching transistor and existing simultaneously on the live and neutral wires, the magnetic fields are superimposed, and the common mode inductor CM1 exhibits high impedance. Therefore, the common mode inductor CM1 effectively suppresses and filters out the high-frequency common mode electromagnetic interference (EMI) conducted outward through the AC output port, preventing the noise generated by the inverter from polluting the power grid or interfering with other sensitive equipment. At the same time, it can also enhance the equipment's resistance to external common mode interference and improve the electromagnetic compatibility (EMC) level of the system.

[0059] In one embodiment, such as Figure 5 As shown, the power supply assembly 120 includes N cascaded power supply modules, each power supply module including a battery module and a bidirectional converter electrically connected to the battery module; wherein, the neutral output terminal of the bidirectional converter of the nth power supply module is connected to the live output terminal of the bidirectional converter of the (n+1)th power supply module, n=[1,…,N-1]; the live connection terminal of the bidirectional converter of the first power supply module is connected to the live connection terminal of the third terminal of the switching assembly 110; the neutral connection terminal of the bidirectional converter of the Nth power supply module is connected to the neutral connection terminal of the third terminal of the switching assembly 110.

[0060] It should be noted that each power module in this embodiment is a fully functional subunit, containing a battery module (for energy storage) and a bidirectional converter electrically connected to the battery module (for converting between DC and AC power). During discharge, it inverts the DC power from its own battery module into AC power for output; during charging, it rectifies the externally input AC power into DC power to charge the battery module. This embodiment constructs a modular and scalable power system by cascading N power modules containing battery modules and bidirectional converters, achieving flexible configuration of system capacity and output voltage, and improving the product's applicability and maintainability.

[0061] Figure 5 The diagram shown is a structural schematic of the third type of single-phase energy storage power supply 100 provided in this application embodiment; as shown Figure 5 As shown, the main control unit 130 in this embodiment includes a level detection circuit 131. The input terminal of the level detection circuit 131 is connected to the communication input interface and is configured to detect the level state of the communication input interface. Specifically, the level detection circuit 131 can be composed of circuits such as voltage divider resistors, isolation optocouplers, or Schmitt triggers, used to condition, isolate, and shape the voltage signal of the communication input interface, converting it into a digital logic level (such as a high level of 3.3V and a low level of 0V) that the controller 133 can directly recognize and process. The level detection circuit 131 realizes the accurate identification of the working state of the front-end equipment, reliably converting high-level or low-level physical signals into logical information, providing a basis for the controller 133 to determine whether it is in a series expansion system and its own position in the system.

[0062] like Figure 5 As shown, the main control unit 130 in this embodiment also includes a voltage detection circuit 132. The input terminal of the voltage detection circuit 132 is connected to the AC input port and is configured to detect the voltage status of the AC input port. Specifically, the voltage detection point in this embodiment is typically composed of circuits such as a voltage transformer, an operational amplifier, and an ADC (analog-to-digital converter). It samples, reduces, and conditions the AC voltage at the AC input port, and determines whether it exists and whether it is within the effective charging voltage range. This provides a key basis for determining whether the system is currently connected to the grid or in an off-grid state, and, combined with the level detection result, jointly determines the operating mode that the system should enter.

[0063] like Figure 5 As shown, the main control unit 130 in this embodiment also includes a controller 133, which is connected to the level detection circuit 131 and the voltage detection circuit 132 respectively. It is configured to generate switch control signals and power control signals based on the level and voltage states. Specifically, it is typically implemented by a microcontroller unit (MCU) or a digital signal processor (DSP). Internally, it runs a preset control algorithm, performs logical operations and decisions based on the received level and voltage states, and synchronously generates two core control commands based on the decision results: a switch control signal (used to drive the relay combination) and a power control signal (used to control the charging and discharging behavior of the bidirectional converter). The controller 133 in this embodiment transforms simple sensor signals into precise actuator action commands, serving as the computing and control center for automatic identification and seamless switching of operating modes.

[0064] like Figure 6As shown, the main control unit 130 in this embodiment also includes a level control circuit 134. The input terminal of the level control circuit 134 is connected to the controller 133, and the output terminal of the level control circuit 134 is connected to the communication output interface. The level control circuit 134 is configured to control the level state of the communication output interface based on the current working mode determined by the controller 133. Specifically, the level control circuit 134 receives instructions from the controller 133 (the instructions are based on the currently determined working mode) and typically controls the connection between the communication output interface and the power supply (high level) or ground (low level) through a switching transistor (such as a MOSFET) or a driver, thereby outputting a clear level signal to the outside world. This realizes the transmission of the working status information of the unit to the downstream device, forming an information chain for the coordinated operation of the series system, and ensuring the reliable execution of system-level logic such as the priority discharge of the front-end.

[0065] In summary, the level detection circuit 131 and the voltage detection circuit 132 are responsible for collecting internal and external states; the controller 133 integrates and judges the information and makes a decision; the decision result controls the machine's operation through the switch control signal and the power control signal, and informs the downstream equipment of the state through the level control circuit 134, thereby guiding the entire series system to work in an orderly and efficient manner.

[0066] Figure 6 The diagram shown is a structural schematic of a capacity expansion device 10 based on a single-phase energy storage power supply provided in an embodiment of this application; as shown... Figure 7 As shown, the expansion device includes: M single-phase energy storage power supplies 100 as described in the above embodiment, where M is an integer greater than 1; the AC input port of the first single-phase energy storage power supply 100 is configured to be connected to the external power grid, and the AC output port of the m-th single-phase energy storage power supply 100 is connected to the AC input port of the (m+1)-th single-phase energy storage power supply 100 via a power line; the AC output port of the M-th single-phase energy storage power supply 100 is configured to be connected to an external load; the communication output interface of the m-th single-phase energy storage power supply 100 is connected to the communication input interface of the (m+1)-th single-phase energy storage power supply 100 via a communication line; where m = [1, ..., M-1].

[0067] It should be noted that the working principle of the capacity expansion device in this implementation is as follows:

[0068] (1) System initialization: When all power supplies are turned on, the first single-phase energy storage power supply 100 detects that its communication input interface is floating or at the default low level. At the same time, its AC input port is connected to the power grid, thus entering the power grid charging mode (i.e., closing the bypass and charging relay K2), transmitting the power grid to the downstream and charging itself. At the same time, its communication output interface outputs the second level (such as low level).

[0069] (2) Subsequent stage mode trigger: The second power supply detects that its communication input interface is low and that there is a valid voltage at the AC input port, so it also enters the grid charging mode and outputs a low level. This logic is passed on to the next stage, and all power supplies in the system enter the grid charging mode when there is an initial grid connection.

[0070] (3) Discharge and fault switching, specifically including:

[0071] ① Pre-stage priority discharge: When the power grid is disconnected, the first power supply switches to discharge mode because the communication input is low and the AC power is off, and immediately sets its communication output to the first level (such as high level).

[0072] ② Intelligent bypass of the next stage: When the second power supply detects a high level in the communication input, it immediately enters the series bypass mode—only closing the bypass relay K1, without charging or inverting, bypassing the power from the previous stage to the next stage without loss, and keeping the communication output at a high level. This logic is passed on to the next stage, ensuring that only the first power supply inverts and discharges, and that all subsequent power supplies operate in a high-efficiency bypass state.

[0073] ③ Seamless switching: If the first power supply runs out of power, it will stop outputting and set the communication output to a low level. The second power supply detects that the communication input has become low and the AC power has failed, and immediately switches to discharge mode to take over the output. The third and subsequent power supplies, because the communication input is still at a high level, maintain the series bypass mode. Therefore, only one power supply switches modes during the entire process, the system output interruption time is extremely short, and the number of relay actions is minimized.

[0074] Therefore, during discharge, the expansion device in this embodiment does not require multiple energy transfers between power sources, resulting in high system efficiency. During grid charging, only one cable needs to be connected to charge all power sources simultaneously, making operation convenient. When any upstream power source fails or runs out of power during operation, the system can achieve seamless switching, and only the downstream power source at the fault point needs to switch modes. This results in fewer relay actions, high system reliability, low noise, and short voltage interruption time.

[0075] Figure 7 The diagram shown is a flowchart illustrating a control method for a single-phase energy storage power supply according to an embodiment of this application; as follows: Figure 8 As shown, the single-phase energy storage power supply control method applied to the above embodiments specifically includes the following steps:

[0076] Step S100: Detect the level status of the communication input interface and the voltage status of the AC input port.

[0077] Step S200: Based on the level state and voltage state, generate a switch control signal and a power control signal so that the switch component switches between the discharge branch, the bypass branch and the charging branch according to the switch control signal, and the power component charges or discharges under the action of the power control signal and the switch component.

[0078] In one embodiment, a switch control signal and a power control signal are generated based on the level state and voltage state, so that the switch component switches between the discharge branch, the bypass branch, and the charging branch according to the switch control signal, and the power component charges or discharges under the action of the power control signal and the switch component. Specifically, this includes: if the communication input interface is at a first level, the switch component is controlled to switch to the bypass branch, and the power component is controlled to stop charging; if the communication input interface is at a second level and there is a valid charging voltage at the AC input port, the switch component is controlled to switch to both the bypass branch and the charging branch, and the power component is controlled to charge; if the communication input interface is at a second level and there is no valid charging voltage at the AC input port, the switch component is controlled to switch to the discharge branch, and the power component is controlled to discharge.

[0079] It should be noted that the operating mode identification process for a single-phase energy storage power supply is as follows: Figure 9 As shown: When the system powers on or needs to discharge, it first checks the level of the communication input interface. If a first level (high level) is detected, it is determined to be in series bypass mode. The control switch assembly forms only the bypass branch, and the power supply assembly stops charging. If a second level (low level) is detected, the voltage status of the AC input port is further checked. If the voltage is within the normal charging range, it is determined to be in grid charging mode. The control switch assembly forms both the bypass branch and the charging branch simultaneously, and the power supply assembly charges. If there is no effective voltage at the AC port, it is determined to be in discharge mode. The control switch assembly forms the discharge branch, and the power supply assembly discharges.

[0080] In one embodiment, the control method further includes: when the single-phase energy storage power supply is operating in discharge mode or series bypass mode, controlling the communication output interface to output a first level; when the single-phase energy storage power supply is operating in grid charging mode, controlling the communication output interface to output a second level.

[0081] It should be noted that the control logic of the communication output interface is as follows: ​ As shown: When the energy storage power supply has a discharge requirement, the energy storage power supply operates in discharge mode or detects that the communication input interface is at a high level, then the communication output interface outputs a high level; otherwise, it outputs a low level.

[0082] Here, the operating conditions of the capacity expansion device based on single-phase energy storage power supply are described in detail:

[0083] (1) Operating condition 1: Series bypass mode (system expansion discharge)

[0084] Multiple energy storage power supplies are connected sequentially via power and communication lines. Upon system startup, the first power supply, with no AC input voltage and a default low communication input, enters discharge mode, outputting a high level from its communication output interface. The second power supply detects the high communication input and immediately enters series bypass mode, closing only the bypass relay to transfer energy losslessly to the next stage, also outputting a high level from its communication output interface. All subsequent power supplies operate in series bypass mode according to this logic. During this process, the next stage power supply only performs bypass output; its power components do not operate, thus achieving linear capacity superposition and completely avoiding multiple energy transfers between power supplies, resulting in high system efficiency.

[0085] (2) Operating Condition 2: Grid Charging Mode (System Overall Charging)

[0086] Based on a multi-unit series connection, the AC input port of the first power supply is connected to the power grid. When the first power supply detects a low-level communication input and a valid AC input voltage, it enters grid charging mode, simultaneously performing bypass output and charging, and sets its communication output interface to low level. The second power supply, detecting a low-level communication input and a valid AC input voltage (from the bypass output of the preceding stage), also enters grid charging mode. This logic propagates tier by tier, allowing the entire series system to simultaneously charge all power supplies via a single power grid connection, making operation extremely simple. In this mode, the system intelligently coordinates the total charging power to prevent input overload. Its strategy prioritizes high-power charging of subsequent power supplies. When the state of charge (SOC) of a subsequent power supply approaches full and its charging power decreases, the preceding power supply automatically increases its own charging power, ultimately ensuring all power supplies are fully charged evenly. Users can remove a fully charged subsequent power supply from the system at any time for independent use without interrupting the charging process of the preceding power supplies, offering flexibility and convenience.

[0087] (3) Operating Condition 3: Switching from grid charging mode to discharging mode (grid power outage)

[0088] When the system is operating in grid charging mode and the grid suddenly fails, the first power supply detects the AC input loss. Since its communication input is low, it immediately switches to discharge mode and simultaneously sets its communication output interface to high. The second power supply detects the communication input becoming high, and its controller immediately commands the power components to stop charging (i.e., exit the charging EPS / UPS mode). However, since its bypass relay is already closed in grid charging and series bypass modes, it seamlessly transitions to series bypass mode without any relay action, directly bypassing the output of the preceding discharge power. In this process, only the first power supply involves mode switching and relay action; the subsequent power supplies do not switch relays, and energy is directly supplied to the load without interruption or loss.

[0089] (4) Operating Condition 4: Switching from Series Bypass Mode to Discharge Mode (Pre-amplifier Power Supply Depleted)

[0090] When the system is operating in series bypass mode and the first power supply runs out of power, it stops outputting and sets its communication output interface to a low level. At this time, the second power supply detects the AC input loss and the low communication input, immediately switching from series bypass mode to discharge mode to take over power supply, while its communication output interface remains high. Although all subsequent power supplies sense the temporary loss of AC voltage, they all remain in series bypass mode because their communication input remains high (from the second power supply). This process involves only one mode switch and relay action by the second power supply, resulting in extremely short system output interruption time and minimizing the number of relay switches, thus improving system reliability and user experience.

[0091] This application, through the above technical solution, enables multiple single-phase energy storage power supplies to be connected in series to achieve flexible capacity expansion, and brings at least the following beneficial effects:

[0092] (1) Strong and flexible expansion capability: By directly connecting the power line and the communication line, the physical interface limitation of the external expansion box is eliminated, and theoretically an unlimited number of power supply expansions can be realized to meet diverse high-power power demand.

[0093] (2) The system is low in cost and highly portable: It does not require any additional dedicated expansion equipment (such as expansion boxes), which not only significantly reduces the system cost, but also avoids the burden of carrying additional equipment, making the deployment and relocation of large-scale energy storage expansion solutions more convenient and economical.

[0094] (3) Accurate pattern recognition, high efficiency and easy to use: By detecting the level status of the communication interface, it can accurately distinguish between series bypass mode and grid charging mode. During series discharge, the downstream power supply only bypasses energy and does not charge, which fundamentally avoids multiple energy transfer losses between power supplies, resulting in high overall system efficiency. During grid charging, only one plug needs to be connected to the first power supply to charge all power supplies in the series system, without the need to frequently plug and unplug intermediate cables, making operation extremely convenient.

[0095] (4) Intelligent charging strategy and flexible use: In grid charging mode, the system adopts an intelligent coordination strategy that prioritizes charging of downstream power supplies. Users can remove the fully charged downstream power supply from the system at any time for independent use without interrupting the charging process of the upstream power supply, which greatly improves the flexibility of use.

[0096] (5) The system is reliable and operates stably: Based on the communication interface level transmission, the front-end priority discharge logic ensures that the energy storage power supply discharges and switches modes strictly according to the physical connection sequence. This mechanism ensures that the number of relay actions is minimized during system operation and mode switching, effectively reducing operating noise and the number of voltage interruptions at the load end, and improving the reliability of the entire system and the operating stability of the load.

[0097] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0098] In the description of this specification, references to terms such as "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0099] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of this patent application.

Claims

1. A single-phase energy storage power supply, characterized in that, The single-phase energy storage power source includes: A switching assembly, wherein a first end of the switching assembly serves as the AC input port of the single-phase energy storage power supply, and a second end of the switching assembly serves as the AC output port of the single-phase energy storage power supply. The switching assembly is configured to respond to a switching control signal and internally form at least one of a charging branch, a discharging branch, and a bypass branch. A power supply assembly connected to the third terminal of the switch assembly, the power supply assembly being configured to receive electrical energy from the AC input port through the charging branch for charging in response to a power control signal, or to provide electrical energy to the AC output port through the discharging branch. The main control unit has a communication input interface and a communication output interface, and the main control unit is connected to the controlled terminal of the switching component and the controlled terminal of the power supply component, respectively. The main control unit is configured to: detect the level state of the communication input interface and the voltage state of the AC input port, and generate the switch control signal and the power control signal based on the level state and the voltage state; and control the level state of the communication output interface according to the current working mode of the single-phase energy storage power supply.

2. The single-phase energy storage power supply according to claim 1, characterized in that, The switching assembly includes: A bypass relay, wherein the first connection terminal of the bypass relay serves as the first terminal of the switching assembly, the second connection terminal of the bypass relay serves as the second terminal of the switching assembly, and the control terminal of the bypass relay is connected to the main control unit; wherein the bypass relay is used to form the bypass branch; A charging relay, wherein the first connection terminal of the charging relay is connected to the first connection terminal of the bypass relay, the second connection terminal of the charging relay serves as the third terminal of the switching assembly, and the control terminal of the charging relay is connected to the main control unit; wherein the charging relay is used to form the charging branch; A discharge relay, wherein the first connection terminal of the discharge relay is connected to the second connection terminal of the bypass relay, the second connection terminal of the discharge relay is connected to the second connection terminal of the charging relay, and the control terminal of the discharge relay is connected to the main control unit; wherein, the discharge relay is used to form the discharge branch.

3. The single-phase energy storage power supply according to claim 2, characterized in that, The switching assembly further includes: A charging inductor is connected in series on the live wire between the second connection terminal of the charging relay and the power supply assembly. A discharge inductor is connected in series on the live wire between the first connection terminal of the discharge relay and the power supply assembly.

4. The single-phase energy storage power supply according to claim 2, characterized in that, The switching assembly further includes: The first fuse is connected in series on the live wire between the AC input port and the first connection terminal of the charging relay; Or / and, a second fuse, connected in series on the live wire between the second connection terminal of the discharge relay and the AC output port; Or / and a common-mode inductor, connected in series between the second connection terminal of the discharge relay and the AC output port.

5. The single-phase energy storage power supply according to claim 1, characterized in that, The power supply assembly includes N cascaded power modules, each power module including a battery module and a bidirectional converter electrically connected to the battery module; wherein, the neutral output terminal of the bidirectional converter of the nth power module is connected to the live output terminal of the bidirectional converter of the (n+1)th power module, n=[1,…,N-1]; The live wire connection terminal of the bidirectional converter of the first power module is connected to the live wire connection terminal of the third terminal of the switching assembly; the neutral wire connection terminal of the bidirectional converter of the Nth power module is connected to the neutral wire connection terminal of the third terminal of the switching assembly.

6. The single-phase energy storage power supply according to claim 1, characterized in that, The main control unit includes: A level detection circuit, the input of which is connected to the communication input interface and configured to detect the level state of the communication input interface; A voltage detection circuit, wherein the input terminal of the voltage detection circuit is connected to the AC input port and is configured to detect the voltage state of the AC input port; The controller, connected to the level detection circuit and the voltage detection circuit respectively, is configured to generate the switch control signal and the power control signal based on the level state and the voltage state. A level control circuit is provided, wherein the input terminal of the level control circuit is connected to the controller, and the output terminal of the level control circuit is connected to the communication output interface. The level control circuit is configured to control the level state of the communication output interface based on the current operating mode determined by the controller.

7. A capacity expansion device based on a single-phase energy storage power source, characterized in that, The expansion device includes: M single-phase energy storage power sources as described in any one of claims 1-6, where M is an integer greater than 1; The AC input port of the first single-phase energy storage power supply is configured to be connected to the external power grid; the AC output port of the m-th single-phase energy storage power supply is connected to the AC input port of the (m+1)-th single-phase energy storage power supply via a power line; and the AC output port of the M-th single-phase energy storage power supply is configured to be connected to an external load. The communication output interface of the m-th single-phase energy storage power supply is connected to the communication input interface of the (m+1)-th single-phase energy storage power supply via a communication line; where m = [1, ..., M-1].

8. A control method for a single-phase energy storage power supply, characterized in that, The control method, applied to the single-phase energy storage power supply according to any one of claims 1-6, comprises: Detect the level status of the communication input interface and the voltage status of the AC input port; Based on the level state and the voltage state, a switch control signal and a power control signal are generated so that the switch assembly switches between the discharge branch, the bypass branch and the charging branch according to the switch control signal, and the power assembly charges or discharges under the action of the power control signal and the switch assembly.

9. The control method for a single-phase energy storage power supply according to claim 8, characterized in that, The step of generating a switch control signal and a power control signal based on the level state and the voltage state, so as to cause the switch assembly to switch between the discharge branch, the bypass branch and the charging branch according to the switch control signal, and to cause the power assembly to charge or discharge under the action of the power control signal and the switch assembly, includes: If the communication input interface is at the first level, then control the switching component to switch to the bypass branch and control the power supply component to stop charging; If the communication input interface is at the second level and the AC input port has a valid charging voltage, then the switching component is controlled to switch to both the bypass branch and the charging branch simultaneously, and the power supply component is controlled to charge. If the communication input interface is at the second level and the AC input port has no effective charging voltage, then the switching component is controlled to switch to the discharge branch, and the power supply component is controlled to discharge.

10. The control method for a single-phase energy storage power supply according to claim 9, characterized in that, The control method further includes: When the single-phase energy storage power supply is operating in discharge mode or series bypass mode, the communication output interface is controlled to output a first level. When the single-phase energy storage power supply is operating in grid charging mode, the communication output interface is controlled to output a second level.

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