Control methods for photovoltaic-energy storage inverters, photovoltaic-energy storage inverters, and photovoltaic-energy storage systems

Abstract

This specification provides a control method for a photovoltaic-storage inverter, a photovoltaic-storage inverter, and a photovoltaic-storage system. The photovoltaic-storage inverter includes an AC interface, a first battery interface, a second battery interface, a first DC circuit, and a second DC circuit. The AC interface is used to electrically connect to a voltage source network. The first DC circuit is electrically connected to the first battery interface, which is used to electrically connect to a stacked battery module. The second DC circuit is electrically connected to the second battery interface, and the second battery interface is used to electrically connect to a separate battery module. The method includes: monitoring the operating status of the photovoltaic-storage inverter in response to the connection of a separate battery module to the second battery interface; and controlling the second DC circuit according to the operating status of the photovoltaic-storage inverter. By applying this photovoltaic-storage inverter and connecting a separately connected separate battery module to the second battery interface, battery expansion can be achieved.

Description

Technical Field

[0001] This specification relates to the field of energy storage inverter technology, and particularly to a control method for a photovoltaic-energy storage inverter, a photovoltaic-energy storage inverter, and a photovoltaic-energy storage system. Background Technology

[0002] In recent years, residential energy storage systems have developed rapidly and have become an important part of home energy management. As users' electricity demand continues to grow, higher requirements are being placed on the scalability of energy storage systems, namely, the ability to easily and cost-effectively increase battery capacity without replacing core equipment.

[0003] Currently, most mainstream residential energy storage products use a stacked connection between battery modules and power conversion systems (PCS), with electrical and communication connections achieved through fixed interfaces. While this structure facilitates initial installation, battery expansion requires physical connection to the inverter. Adding a new battery necessitates reconnecting it to the inverter's DC input, often necessitating inverter removal or relocation. This results in complex operations, high labor costs, and the need for pre-planned cabling or modifications to power distribution lines, leading to resource waste and a decline in user experience.

[0004] Therefore, how to achieve flexible and online expansion of battery modules without disassembling the inverter or modifying the AC side wiring has become an urgent problem to be solved. Summary of the Invention

[0005] In view of this, embodiments of this specification provide a control method for a photovoltaic-storage inverter. One or more embodiments of this specification also relate to a photovoltaic-storage inverter and a photovoltaic-storage system, to address the technical deficiencies existing in the prior art.

[0006] According to a first aspect of the embodiments of this specification, a control method for a photovoltaic-storage inverter is provided. The photovoltaic-storage inverter includes an AC interface, a first battery interface, a second battery interface, a first DC circuit, and a second DC circuit. The AC interface is used to electrically connect to a voltage source network. The first DC circuit is electrically connected to the first battery interface, which is used to electrically connect to a stacked battery module. The second DC circuit is electrically connected to the second battery interface, which is used to electrically connect to a separate battery module. The method includes: In response to the second battery interface being connected to the split battery module, the operating status of the photovoltaic-storage inverter is monitored; The second DC circuit is controlled according to the operating status of the photovoltaic-storage inverter.

[0007] According to a second aspect of the embodiments of this specification, a photovoltaic-storage inverter is provided, comprising: The system includes an AC interface, a first battery interface, a second battery interface, a first DC circuit, and a second DC circuit. The AC interface is used for electrical connection to a voltage source network. The first DC circuit is electrically connected to the first battery interface, which is used for external electrical connection to a stacked battery module. The second DC circuit is electrically connected to the second battery interface, which is used for external electrical connection to a separate battery module. The voltage source network is electrically connected to the photovoltaic-storage inverter via an AC interface, the stacked battery module is electrically connected to the photovoltaic-storage inverter via a first battery interface to form a first DC circuit, and the split battery module is electrically connected to the photovoltaic-storage inverter via a second battery interface to form a second DC circuit.

[0008] According to a third aspect of the embodiments of this specification, an optical energy storage system is provided, comprising: Photovoltaic-storage inverters, as well as photovoltaic modules, voltage source networks, stacked battery modules, and split battery modules connected to the photovoltaic-storage inverters; Among them, the stacked battery module is electrically connected to the photovoltaic-storage inverter to form the first DC circuit; The separate battery module is electrically connected to the photovoltaic-storage inverter to form a second DC circuit.

[0009] The photovoltaic-storage inverter provided in one or more embodiments of this specification includes: an AC interface, a first battery interface, a second battery interface, a first DC circuit, and a second DC circuit. The AC interface is used to electrically connect to a voltage source network, the first DC circuit is electrically connected to the first battery interface, the first battery interface is used to electrically connect to a stacked battery module, and the second DC circuit is electrically connected to the second battery interface, and the second battery interface is used to electrically connect to a separate battery module.

[0010] The control method for a photovoltaic-storage inverter provided in one or more embodiments of this specification includes: monitoring the operating status of the photovoltaic-storage inverter in response to the connection of a split battery module to the second battery interface; and controlling the second DC circuit according to the operating status of the photovoltaic-storage inverter, thereby realizing multi-dimensional, adaptive power management of the split battery circuit. Therefore, when users need to expand battery capacity, there is no need to disassemble the inverter or modify the AC side wiring. Simply connect the split battery module to the second battery interface to achieve online expansion of battery capacity. The first DC circuit and the second DC circuit do not interfere with each other, and the connection, disconnection, or failure of any battery module does not affect the normal operation of the other battery circuit. This reduces the difficulty and labor costs of capacity expansion operations, avoids resource waste caused by line modifications and cable pre-installation, and improves the user experience. Attached Figure Description

[0011] Figure 1 A flowchart illustrating a control method for a photovoltaic-storage inverter, provided as one embodiment of this specification; Figure 2This specification provides a schematic diagram of the structure of a photovoltaic-storage inverter according to one embodiment. Figure 3 This specification provides a schematic diagram of the structure of a photovoltaic energy storage system according to one embodiment. Figure 4 This is a schematic diagram of the structure of another optical energy storage system provided in one embodiment of this specification; Figure 5 A schematic diagram of a light storage system including a soft-start circuit is provided as an embodiment of this specification; Figure 6 A schematic diagram of a photovoltaic energy storage system with a controller mounted on a battery module, provided as one embodiment of this specification; Figure 7 A circuit diagram of a soft-start circuit provided for one embodiment of this specification; Figure 8 A circuit diagram of yet another soft-start circuit provided in one embodiment of this specification; Figure 9 A circuit diagram of another soft-start circuit provided as an embodiment of this specification; Figure 10 A schematic diagram of the architecture of a soft-start circuit provided for one embodiment of this specification; Figure 11 A schematic diagram of another soft-start circuit architecture provided in one embodiment of this specification; Figure 12 A schematic diagram of another soft-start circuit architecture provided for one embodiment of this specification; Figure 13 A schematic diagram of a transformer circuit installed on a busbar is provided as an embodiment of this specification; Figure 14 A schematic diagram of another transformer circuit installed on the busbar, provided as an embodiment of this specification; Figure 15 A schematic diagram of another transformer circuit disposed on the busbar is provided as an embodiment of this specification; Figure 16 A schematic diagram of another transformer circuit installed on the busbar, provided as an embodiment of this specification; Figure 17 This specification provides a schematic diagram of a transformer circuit disposed on a split battery module, as an embodiment of the present specification. Figure 18 This is a schematic diagram of another transformer circuit provided on a split battery module, as an embodiment of this specification.

[0012] Figure label: 1-Photovoltaic-storage inverter; 11-Photovoltaic module; 12-Photovoltaic transformer circuit; 13-Inverter circuit; 14-AC interface; 15-Inverter DC bus; 16-Main controller; 17-First battery interface; 18-Second battery interface; 19-Photovoltaic interface; 2 - Stacked battery modules; 21 - First sub-controller, 22 - Transformer circuit, 23 - Battery; 3 - Separate battery module; 31 - Second sub-controller; 32 - Soft start circuit; 41 – Communication bus, 42 – First communication interface, 43 – Second communication interface; 51 - Soft start circuit input terminal, 52 - Soft start circuit output terminal, 53 - Controllable mechanical switch, 54 - Soft start resistor, 55 - Semiconductor switch, 56 - Diode; 6- Photovoltaic-Storage System. Detailed Implementation

[0013] Many specific details are set forth in the following description to provide a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this specification. Therefore, this specification is not limited to the specific implementations disclosed below.

[0014] The terminology used in one or more embodiments of this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the one or more embodiments of this specification. The singular forms “a,” “described,” and “the” used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items. The term “at least one” in one or more embodiments of this application means “one or more,” and “a plurality of” means “two or more.” The term “comprising” is an open-ended description and should be understood as “including but not limiting,” and may include other content in addition to what has been described.

[0015] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this specification, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this specification, and similarly, second may also be referred to as first. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0016] Furthermore, it should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in one or more embodiments of this specification are all information and data authorized by the user or fully authorized by all parties. Moreover, the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0017] First, the terms and concepts used in one or more embodiments of this specification will be explained.

[0018] Photovoltaic-storage inverter: A power electronic device that can simultaneously connect to photovoltaic modules and battery energy storage units and realize power conversion and management. It is used to convert the DC power generated by the photovoltaic module, control the charging and discharging of the battery, and convert the DC power into AC power to supply the load or connect to the grid. It includes residential photovoltaic-storage integrated machines and industrial and commercial photovoltaic-storage inverter equipment.

[0019] This specification provides a control method for a photovoltaic-storage inverter. This specification also relates to a photovoltaic-storage inverter, which will be described in detail in the following embodiments.

[0020] See Figure 1 , Figure 1 This document provides a flowchart of a control method for a photovoltaic-storage inverter, as an embodiment of the present specification. The inverter includes an AC interface, a first battery interface, a second battery interface, a first DC circuit, and a second DC circuit. The AC interface is electrically connected to a voltage source network. The first DC circuit is electrically connected to the first battery interface, which is used for external electrical connection to a stacked battery module. The second DC circuit is electrically connected to the second battery interface, which is used for external electrical connection to a separate battery module. The method specifically includes the following steps: Step 102: In response to the second battery interface being connected to the split battery module, monitor the operating status of the photovoltaic-storage inverter; A photovoltaic-storage inverter is a power electronic device that integrates photovoltaic input management and energy storage battery management functions. It is used to convert DC power generated by photovoltaic modules into AC power, convert electrical energy from voltage source networks into DC power to charge batteries, and convert DC power stored in batteries into AC power to supply power to loads. Its applications include residential photovoltaic-storage integrated units, stacked energy storage inverters, hybrid photovoltaic energy storage inverters, and so on.

[0021] A voltage source network is a public power system consisting of power plants, transmission lines, substations, and distribution networks, used to provide alternating current or receive grid-connected power, such as power grids, residential grid connections, generators, etc.

[0022] The voltage source network operating status is a set of parameters characterizing the current operating conditions of the voltage source network connected to the AC interface. It is used to describe the voltage quality, frequency characteristics, and grid interconnection capability of the power grid, such as the effective value of the grid voltage, grid frequency, active power, reactive power, grid connection switch status, islanding detection flag, grid voltage fluctuation value, phase angle difference, etc.

[0023] The AC interface is the input / output port on the photovoltaic-storage inverter used to connect to the voltage source network or AC load, enabling bidirectional power exchange between the inverter and the AC side, such as standardized AC terminals, grid connection interfaces, etc.

[0024] The electrical connection between the first battery interface and the stacked battery module can be a stacked plug-in connection. The stacked plug-in connection is an installation method in which the battery module and the photovoltaic-storage inverter are connected by direct plugging. It is used to combine the battery module and the inverter into an integrated structure in the vertical or horizontal direction. For example, the bottom of the battery module and the top of the inverter are connected by a jet plug, multiple battery modules are cascaded and expanded by stacking and plugging, and plug-in battery units are inserted into the back panel of the cabinet to complete the connection, etc.

[0025] The electrical connection between the second battery interface and the separate battery module can be a separate connection. A separate connection is an installation form in which the battery module and the photovoltaic-storage inverter are electrically and communicatively connected through cables or other detachable methods. This is used to physically separate the battery module and the inverter and keep the battery module in a replaceable state at any time. For example, it can be connected through prefabricated power cables with connectors, through pluggable terminal blocks with multi-core flexible wires, or through quick-connect connectors and flexible cables, etc.

[0026] A logical association that responds to the detection or receipt of a certain triggering condition or event to perform a corresponding operation, indicating the relationship between the occurrence of the operation and a specific condition or event, such as monitoring the operating status of the photovoltaic-storage inverter in response to the connection of a split battery module to a second battery interface, or controlling the battery module to supply power to the load in response to the connection of a load to an AC interface, etc.

[0027] An electrical connection is established between the separate battery module and the second battery interface of the photovoltaic-energy storage inverter, enabling the separate battery module to transmit power or communicate with the inverter via a second DC circuit. This connection status can typically be identified by the photovoltaic-energy storage inverter by detecting voltage, current, or communication signals at the interface. For example, the connector of the separate battery module is physically engaged with the second battery interface and electrically connected, or the photovoltaic-energy storage inverter receives a handshake signal sent by the separate battery module.

[0028] Monitoring refers to the act of independently sensing and acquiring the operating status of multiple battery modules. It is used to establish a separate status observation channel for each battery circuit, such as collecting the voltage of stacked battery modules through independent sensors and reading the state of charge of separate battery modules through another independent sensor.

[0029] Stacked battery modules are collections of battery units that connect to photovoltaic-energy storage inverters via a stacked plug-in method. They are used to form an integrated stacked installation with the inverter in terms of physical structure. Electrical and communication connections can be achieved through rigid connections or other strong connection methods. Stacked battery modules can be standardized high-voltage battery packs, modular energy storage units, etc. Connection methods can include plug-in connections, copper busbars and bolt fastening, cabinet backplate and plug-in connectors, etc.

[0030] The stacked battery module operating status is a set of parameters characterizing the current operating conditions of the stacked battery modules connected by the first battery interface. It is used to describe the electrical characteristics, health status, and interaction with the inverter of the stacked battery modules, such as battery voltage, state of charge, temperature, charging and discharging current, fault flag bits, communication connection status with the main controller, pre-charge completion flag of the soft-start circuit, output voltage feedback of the transformer circuit, etc.

[0031] A separate battery module is a collection of battery units that are connected to a photovoltaic-storage inverter via a separate connection method. It is designed to be physically separated from the inverter and to achieve electrical and communication connections via cables or other detachable methods. Separate battery modules can be such as independently placed floor-standing battery cabinets, wall-mounted battery boxes, etc., and the connection methods can be prefabricated power cables with connectors, pluggable terminals, quick-connect fittings, flexible cables, etc.

[0032] The operating status of a split battery module is a set of parameters characterizing the current operating conditions of the split battery module connected separately through the second battery interface. It is used to describe the electrical characteristics, health status, and interaction with the inverter of the split battery module, such as the battery voltage, state of charge, temperature, charging and discharging current, fault flag, communication connection status with the main controller, pre-charge completion flag of the soft start circuit, connection status of the split connection cable, etc.

[0033] The operating status of a photovoltaic-storage inverter is a comprehensive set of parameters characterizing the overall working conditions of the inverter. It can be determined based on at least one of the photovoltaic interface operating status, voltage source network operating status, stacked battery module operating status, and separate battery module operating status. It is used to describe the current macroscopic working mode or operating condition stage of the photovoltaic-storage inverter to support the unified scheduling and decision-making of battery circuit charging and discharging power, such as multi-battery operating status, photovoltaic charging status, battery charging status, battery discharging status, fault protection status, standby status, grid-connected status, off-grid status, etc.

[0034] This step uses the built-in monitoring unit or communication interface of the photovoltaic-storage inverter to acquire the operating parameters of both the stacked battery modules and the individually connected battery modules in real time. Through separate monitoring, the system establishes a state-aware foundation for two independent battery circuits, ensuring that parameter changes in either battery module are accurately identified without mutual interference. This provides a data foundation for subsequent decoupled control of the battery circuits, arbitrary sequence start-up, and differentiated interface management. This allows users to expand battery capacity without disassembling the inverter or modifying AC lines; they can simply connect the new battery module through the individual interface to complete online capacity expansion, reducing labor costs and avoiding resource waste.

[0035] Step 104: Control the second DC circuit according to the operating status of the photovoltaic-storage inverter.

[0036] The first DC circuit is an electrical path consisting of the first battery interface, connecting lines, and stacked battery modules. It is used to carry the bidirectional flow of electrical energy between the stacked battery modules and the photovoltaic-storage inverter. This path can be equipped with functional circuits such as soft-start circuits, boost circuits, and filter circuits. For example, there is a charging and discharging loop formed by the stacked battery modules and the inverter DC bus through the aviation plug, a pre-charge protection path including a soft-start circuit, a voltage regulation path with a transformer circuit, and so on.

[0037] The second DC circuit is an electrical path consisting of the second battery interface, connecting cables, and the split battery module. It is used to carry the bidirectional flow of electrical energy between the split battery module and the photovoltaic-storage inverter. This path can be equipped with one or more of the following: a soft-start circuit, a boost circuit, and a filter circuit. It can be a charging and discharging loop formed by the split battery and the inverter DC bus through the connecting copper busbar, a protective path including an independent soft-start circuit, a voltage regulation path with a transformer circuit, etc.

[0038] Control refers to the behavior of generating and executing adjustment commands based on the monitored operating status. This is used to adjust the direction, amplitude, or on / off state of electrical energy flow in the battery circuit. For example, it can change the charging current by adjusting the voltage difference between the bus voltage and the battery voltage, complete pre-charging and bypass switching by controlling the on / off state of the controllable mechanical switch or semiconductor switch in the soft start circuit, send charging and discharging power commands to the sub-controller of the battery module through the communication interface, cut off the corresponding battery circuit and maintain the normal operation of other circuits when a fault condition is detected, and block the current path when the battery is reverse connected through the reverse connection protection circuit, etc.

[0039] Charging and discharging power refers to the electrical energy absorbed or released by a battery module per unit time, used to quantify the battery's charging rate or discharging capacity. Charging power can come from photovoltaic modules connected via the photovoltaic interface, rectified power supplied by a voltage source network connected via the AC interface, or electrical energy released by another battery module connected in parallel to the same bus. Discharging power can flow to AC loads connected via the AC interface, be fed back to the voltage source network, or provide charging power to another battery module connected in parallel to the same bus. The specific value of charging and discharging power is determined by factors such as the voltage difference between the bus voltage and the battery voltage, the duty cycle of the switching transistor, the current limiting effect of the soft-start circuit during the pre-charging stage, the voltage transformation relationship of the boost circuit, and the charging or discharging rate requested by the battery management system.

[0040] The control of the second DC circuit can be based on the operating status of the photovoltaic-storage inverter. This can include several scenarios. One possibility is that when the operating status is charging, the second DC circuit is controlled to supply power to the separate battery module. Another possibility is that when the operating status is discharging, the second DC circuit is controlled to receive the electrical energy released by the separate battery module. Yet another possibility is that when the operating status is faulty, the second DC circuit is disconnected.

[0041] More specifically, the charging and discharging power flowing through the second DC circuit can be controlled according to the operating status of the photovoltaic-storage inverter. Controlling the charging and discharging power flowing through the second DC circuit based on the operating status of the photovoltaic-storage inverter can include various scenarios. One possible scenario is power allocation in a multi-battery operating state: when the operating state is multi-battery, i.e., both stacked battery modules and separate battery modules are connected, the charging and discharging power of the second DC circuit is allocated based on the state of charge, health, or voltage difference between the two battery modules. For example, comparing the state of charge of the first battery module with that of the separate battery module, the battery with the higher state of charge is prioritized for discharging, and the battery with the lower state of charge is prioritized for charging.

[0042] This specification describes an embodiment that monitors the operating status of the photovoltaic-storage inverter. The operating status is determined based on at least one of the following: the photovoltaic interface operating status, the voltage source network operating status, the stacked battery module operating status, and the individual battery module operating status. The inverter then controls the charging and discharging power flowing through the second DC circuit based on this operating status. This allows the inverter to make unified decisions by integrating the current states of multiple components, thereby implementing precise power regulation of the second DC circuit connected in separate configurations. Therefore, when users need to expand battery capacity, there is no need to disassemble the already stacked battery modules or modify the AC wiring. They only need to connect the newly added individual battery module through the second battery interface. The system can automatically sense and integrate various operating states to control the charging and discharging of the second DC circuit, achieving flexible online capacity expansion and reducing labor costs and resource waste. Simultaneously, the multi-source operating status-based control method avoids power misadjustment caused by misjudgment of a single state, improving the system's adaptability and reliability under different operating conditions, enabling the stacked and individual batteries to operate in a coordinated and efficient manner.

[0043] In one optional embodiment of this specification, the second DC circuit is controlled according to the operating state of the photovoltaic-storage inverter, including: The charging and discharging status of the second DC circuit is controlled according to the operating status of the photovoltaic-storage inverter. The operating status includes charging status, discharging status, or fault status.

[0044] The charging state is an operating condition of a photovoltaic-storage inverter, indicating that the inverter obtains electrical energy from an external power source and transmits it to the individual battery modules for storage via a second DC circuit. In this state, the second DC circuit can be configured to allow current to flow towards the individual battery modules. The charging state does not preclude the possibility of simultaneously charging the stacked battery modules. Charging states can include photovoltaic charging state and voltage source network charging state. Furthermore, for different batteries, there are charging methods such as stacked battery module charging, individual battery module charging, and simultaneous charging of dual battery modules (stacked battery module and individual battery module), etc.

[0045] The discharge state is an operating condition of a photovoltaic-storage inverter, indicating that the individual battery modules release electrical energy to the inverter through a second DC circuit, and the inverter then transmits this energy to external devices such as voltage source networks and loads. In this state, the second DC circuit can be configured to allow current to flow out of the individual battery modules. Discharge states can include stacked battery module discharge, individual battery module discharge, and joint discharge of dual battery modules (stacked battery module and individual battery module), etc.

[0046] A fault state is an operating condition of a photovoltaic-storage inverter, indicating a situation in the inverter, stacked battery module, or separate battery module that does not meet normal operating expectations, such as abnormal voltage, abnormal current, communication interruption, or excessive temperature. In this state, control of the second DC circuit may include disconnecting the second DC circuit to prevent the abnormality from escalating or to protect the equipment. However, the fault state does not preclude the possibility of maintaining partial circuit conduction under certain fault conditions.

[0047] One possible scenario is charging control during photovoltaic charging: When the operating state is photovoltaic charging, i.e., the photovoltaic input voltage is greater than the preset supply voltage, the second DC circuit is controlled to obtain power from the photovoltaic interface for charging, and the charging power of the second DC circuit is adjusted according to the photovoltaic power fluctuation. For example, the charging power is increased when the light intensity is enhanced and decreased when the light intensity is weakened. Alternatively, the charging power is decreased when the state of charge of the split battery module exceeds the preset high charge threshold and increased when the state of charge of the split battery module is lower than the preset low charge threshold.

[0048] One possible scenario is soft-start current limiting during battery charging: When the operating state is battery charging, the initial charging current is limited by the second soft-start circuit connected in series in the second DC circuit to achieve soft start, and the bypass current limiting resistor is used after pre-charging is completed to restore normal charging power.

[0049] One possible scenario is load power supply during battery discharge: When the operating state is battery discharge, such as when the AC interface is connected to the load, or when the power grid is interrupted or the system is off-grid, the second DC circuit is controlled to supply power to the load through the AC interface, and the discharge power is adjusted according to the load power demand.

[0050] One possible scenario is circuit disconnection under fault protection conditions: when the operating state is a fault state of the split battery module, such as overvoltage, overtemperature, overcurrent, or communication interruption, the second DC circuit is disconnected, reducing the charging and discharging power to zero, while maintaining the normal operation of the first DC circuit.

[0051] One possible scenario is power maintenance in standby mode: when the operating state is standby, with no photovoltaic input, no load, and no grid interaction requirements, the charging and discharging power of the second DC circuit is controlled to be zero, or to maintain extremely low self-maintenance power consumption.

[0052] One possible scenario is the charging and discharging scheduling under grid-connected conditions: When the operating state is grid-connected, the second DC circuit is controlled to charge during the low electricity price period and discharge during the high electricity price period, in accordance with grid instructions or peak-valley electricity price strategies, to achieve peak shaving and valley filling.

[0053] One possible scenario is coordinated control in a mixed state: when the operating state simultaneously includes multiple sub-states, such as photovoltaic charging state + multi-battery operating state + battery charging state, the charging and discharging power of the second DC circuit is coordinated to avoid overcharging or over-discharging. For example, when the photovoltaic power is sufficient, the battery with a lower state of charge is charged first, and when the load suddenly increases, the stacked battery module and the separate battery module discharge simultaneously.

[0054] This specification's embodiments control the charging and discharging state of the second DC circuit based on the operating status of the photovoltaic-storage inverter, enabling flexible management of the separate battery modules. In charging mode, the photovoltaic-storage inverter can obtain power from different external power sources and selectively charge the separate battery modules, stacked battery modules, or both simultaneously, helping to improve energy utilization efficiency and system configuration adaptability. In discharging mode, the separate battery modules can be controlled to supply power individually or collaboratively with stacked battery modules as needed, meeting the requirements of different loads or grid-connected scenarios. In fault conditions, the risk of abnormal expansion can be reduced and equipment safety protected by methods such as disconnecting the second DC circuit. Furthermore, this method is compatible with both single-cell and dual-cell simultaneous access scenarios, improving the operational reliability and flexibility of the photovoltaic-storage system without excluding any operating mode.

[0055] One optional embodiment of this specification monitors the operating status of the photovoltaic-storage inverter in a multi-battery operation state, including: In the multi-battery operation mode, the operation status of the stacked battery module connected to the photovoltaic-storage inverter and the operation status of the split battery module connected to the photovoltaic-storage inverter are monitored respectively. The operating status of the photovoltaic-storage inverter is determined based on the operating status of the stacked battery modules and the operating status of the separate battery modules.

[0056] The operating status of a stacked battery module can include its voltage status, current status, state of charge, temperature status, health status, communication status, and fault status, etc.

[0057] The operating status of a separate battery module can include its voltage status, current status, state of charge, temperature status, health status, communication status, and fault status, etc.

[0058] One possible scenario is that, based on the state of charge, charging and discharging current, and temperature of the stacked battery module and the separate battery module, if both modules are within the normal range of charging and discharging, then the photovoltaic-storage inverter is determined to be in normal dual-battery operation mode; if one of them has a state of charge below the discharge cutoff threshold, then the photovoltaic-storage inverter is determined to be in single-battery discharge mode or grid-supplemented power supply mode.

[0059] One possible scenario is that, based on the output power status of the photovoltaic module and the charging requirements of the stacked battery module and the separate battery module, if the photovoltaic input voltage is greater than the preset supply voltage and at least one battery module is not fully charged, then the photovoltaic-storage inverter is determined to be in photovoltaic charging mode; if the photovoltaic power is insufficient to meet the charging requirements of the two battery modules, then the photovoltaic-storage inverter is determined to enter single-battery priority charging mode or grid power supply mode.

[0060] One possible scenario is that, considering the connection status of the voltage source network and the load power status, when neither the stacked battery module nor the separate battery module can provide the power required by the load, the photovoltaic-storage inverter is determined to be operating in grid-fed mode.

[0061] One possible scenario is that by combining the voltage, current, and fault flag bits of the stacked battery modules, separate battery modules, and photovoltaic modules, and through preset logic priorities, the final operating state of the photovoltaic-storage inverter can be determined. This operating state can include photovoltaic charging state, grid charging state, battery discharging state, fault standby state, etc.

[0062] This specification's embodiments acquire the independent operating status of stacked battery modules and separate battery modules, enabling the identification of differences in operating conditions among modules when multiple batteries are connected simultaneously. By monitoring each module separately, the normal operation of another module can be maintained even if one module malfunctions, preventing a single point of failure from causing a system-wide shutdown. This improves the fault tolerance and power supply reliability of the photovoltaic-storage inverter under multi-battery operation. Furthermore, the status data obtained from separate monitoring provides a basis for subsequent charging and discharging strategy optimization, fault isolation, and energy dispatching, facilitating adaptation to practical application scenarios such as different battery types or the mixing of new and old batteries.

[0063] One optional embodiment of this specification monitors the operating status of a photovoltaic-storage inverter, including: In response to the first battery interface being connected to the stacked battery module and the second battery interface being connected to the split battery module, the operating state of the photovoltaic-storage inverter is determined to be a multi-battery operating state. Monitor the operating status of the photovoltaic-storage inverter under multi-battery operation conditions; Controlling the second DC circuit based on the operating status of the photovoltaic-storage inverter also includes: The first and second DC circuits are controlled according to the operating status of the photovoltaic-storage inverter.

[0064] Access is the process of establishing electrical and communication connections between battery modules and photovoltaic-storage inverters, enabling battery modules to exchange power and information with inverters. For example, connecting stacked batteries via plug-and-play connectors, connecting separate batteries via power cables and communication cables, and quickly installing battery modules via pluggable terminals, etc.

[0065] The first battery access status is a parameter that characterizes whether the stacked battery module has established an electrical and communication connection with the photovoltaic-storage inverter through the first battery interface. It is used to indicate whether the stacked battery module is in a ready state that can be identified and scheduled by the system. For example, the voltage detection flag of the first battery interface is set, the handshake signal of the first sub-controller is successfully received, the contactor feedback closing signal of the first DC circuit is received, the identification code of the stacked battery module is read and confirmed by the main controller, etc.

[0066] The second battery access status is a parameter characterizing whether the split battery module has established an electrical and communication connection with the photovoltaic-storage inverter through the second battery interface. It is used to indicate whether the split battery module is in a ready state that can be identified and scheduled by the system. For example, the voltage detection flag of the second battery interface is set, the handshake signal of the second sub-controller is successfully received, the contactor feedback closing signal of the second DC circuit is received, the identification code of the split battery module is read and confirmed by the main controller, etc.

[0067] Multi-battery operation mode is a working state of photovoltaic-storage inverter, used to manage the charging and discharging process of at least two battery modules simultaneously. In this mode, the inverter can monitor the operating status of each battery module and independently control the charging and discharging power of each battery circuit. Examples include parallel operation mode where the first DC circuit and the second DC circuit are both active, polling operation mode where the two battery modules alternately charge and discharge, or bidirectional scheduling mode where one battery module is charging while the other battery module is discharging, etc.

[0068] Controlling the first and second DC circuits based on the operating status of the photovoltaic-storage inverter can be achieved in various ways: One possible approach is to disconnect the first DC circuit and keep the second DC circuit open in the event of a stacked battery module failure during operation. Another possible approach is to disconnect the second DC circuit while maintaining the first DC circuit in the event of a fault in the split battery module during operation. Another possible approach is to control the first DC circuit to supply power to the stacked battery module and control the second DC circuit to supply power to the separate battery module when the dual batteries are charging together. Another possible approach is to control the first DC circuit to receive the electrical energy released by the stacked battery module and control the second DC circuit to receive the electrical energy released by the separate battery module when the dual battery is discharging together. Another possible approach is to disconnect one of the first or second DC circuits when only a single battery is needed for operation, while maintaining only the other circuit.

[0069] This embodiment monitors whether the stacked battery module and the separate battery module are connected through the first battery interface and the second battery interface, respectively, to determine the first battery connection status and the second battery connection status. Based on this, the operating status of the photovoltaic-storage inverter is determined to be a multi-battery operating state. In this multi-battery operating state, further monitoring is performed, enabling the system to automatically identify scenarios where both stacked and separate batteries are ready. The multi-battery operating mode and corresponding status monitoring mechanism are only activated when both batteries are connected. This avoids the waste of computational resources caused by unnecessary multi-battery status monitoring in single-battery scenarios, while ensuring that the status observation channels for the two battery loops can be accurately established in multi-battery scenarios. This provides a reliable operating environment foundation for subsequent independent power control and fault isolation, improving the system's resource utilization efficiency and scenario adaptability.

[0070] One optional embodiment of this specification includes: Based on the operating status of the photovoltaic-storage inverter, the charging and discharging power flowing through the first DC circuit and the second DC circuit is controlled respectively.

[0071] The charging and discharging power flowing through the second DC circuit is controlled according to the operating status of the photovoltaic-storage inverter. This can include various situations. One possible situation is power allocation in the multi-battery operating state: when the operating state is multi-battery operating state, that is, when both the stacked battery module and the separate battery module are connected, the charging and discharging power of the second DC circuit is allocated according to the state of charge, health, or voltage difference of the two battery modules. For example, the state of charge of the first battery module is compared with the state of charge of the separate battery module, and the battery with the higher state of charge is given priority to discharge and the battery with the lower state of charge is given priority to charge.

[0072] One possible scenario is charging control during photovoltaic charging: When the operating state is photovoltaic charging, i.e., the photovoltaic input voltage is greater than the preset supply voltage, the second DC circuit is controlled to obtain power from the photovoltaic interface for charging, and the charging power of the second DC circuit is adjusted according to the photovoltaic power fluctuation. For example, the charging power is increased when the light intensity is enhanced and decreased when the light intensity is weakened. Alternatively, the charging power is decreased when the state of charge of the split battery module exceeds the preset high charge threshold and increased when the state of charge of the split battery module is lower than the preset low charge threshold.

[0073] One possible scenario is soft-start current limiting during battery charging: When the operating state is battery charging, the initial charging current is limited by the second soft-start circuit connected in series in the second DC circuit to achieve soft start, and the current limiting resistor is bypassed after pre-charging to restore normal charging power; and / or, the initial charging current is limited by the first soft-start circuit connected in series in the first DC circuit to achieve soft start, and the current limiting resistor is bypassed after pre-charging to restore normal charging power.

[0074] One possible scenario is power supply to the load while the battery is discharging: When the operating state is battery discharging, such as when the AC interface is connected to the load, the grid is disconnected, or the system is off-grid, the second DC circuit is controlled to supply power to the load through the AC interface, and the discharge power is adjusted according to the load power demand. And / or, the first DC circuit is controlled to supply power to the load through the AC interface, and the discharge power is adjusted according to the load power demand.

[0075] One possible scenario is circuit disconnection under fault protection conditions: when the operating state is a fault state of the split battery module, such as overvoltage, overtemperature, overcurrent, or communication interruption, the second DC circuit is disconnected, causing the charging and discharging power to drop to zero, while maintaining the normal operation of the first DC circuit. When the operating status is a stacked battery module fault state, such as overvoltage, overtemperature, overcurrent, or communication interruption, the first DC circuit is cut off, reducing the charging and discharging power to zero, while maintaining the normal operation of the second DC circuit.

[0076] One possible scenario is power maintenance in standby mode: when the operating state is standby, with no photovoltaic input, no load, and no grid interaction requirements, the charging and discharging power of the first DC circuit and the second DC circuit is controlled to be zero, or to maintain extremely low self-maintenance power consumption.

[0077] One possible scenario is the charging and discharging scheduling under grid-connected conditions: When the operating state is grid-connected, according to grid instructions or peak-valley pricing strategies, the second DC circuit and / or the first DC circuit are controlled to charge during the low-price period and discharge during the high-price period to achieve peak shaving and valley filling.

[0078] One possible scenario is coordinated control in a mixed state: when the operating state simultaneously includes multiple sub-states, such as photovoltaic charging state + multi-battery operating state + battery charging state, the charging and discharging power of the second DC circuit and the first DC circuit is coordinated to avoid overcharging or over-discharging. For example, when the photovoltaic power is sufficient, the battery with a lower state of charge is charged first, and when the load suddenly increases, the stacked battery module and the separate battery module discharge simultaneously.

[0079] This specification describes an embodiment that independently controls the charging and discharging power flowing through the first and second DC circuits based on the operating status of the photovoltaic-storage inverter. This allows the system to flexibly adapt power scheduling strategies to different operating conditions. Through independent control in various scenarios, the photovoltaic-storage inverter can adaptively optimize power distribution and scheduling between the two battery circuits, significantly improving the system's scenario adaptability, energy efficiency, fault tolerance, and battery module lifespan. This provides users with a more flexible, reliable, and economical photovoltaic-storage solution.

[0080] In one optional embodiment of this specification, the operating states of the photovoltaic-storage inverter also include stacked battery module failure and separate battery module failure. Based on the operating status of the photovoltaic-storage inverter, the first DC circuit and the second DC circuit are controlled, including: In the event of a stacked battery module failure during operation, the first DC circuit is disconnected while the second DC circuit is maintained. In the event of a fault in the separate battery module during operation, the second DC circuit is disconnected while the first DC circuit is maintained.

[0081] A fault is a state that deviates from the normal operating conditions of the battery module during operation. It is used to trigger protective operations to prevent the fault from spreading or causing safety accidents. Examples include battery voltage exceeding the overvoltage protection threshold, battery voltage falling below the undervoltage protection threshold, battery temperature exceeding the overtemperature protection threshold, charging and discharging current exceeding the overcurrent protection threshold, the battery management system detecting an internal short circuit, communication connection interruption exceeding a preset time, insulation resistance dropping below a safe value, etc.

[0082] The fault occurs when the monitored operating status parameters determine that the fault condition is met. This is used as the trigger condition for executing the circuit disconnection operation. For example, when the monitored battery voltage value exceeds the preset overvoltage threshold, an overvoltage fault is determined to have occurred; when the monitored temperature value exceeds the preset overtemperature threshold, an overtemperature fault is determined to have occurred; when the received fault flag bit is set, a corresponding type of fault is determined to have occurred, and so on.

[0083] A stacked battery module failure refers to an abnormal state that deviates from normal operating conditions during the operation of the stacked battery module. It is used to trigger protective operations on the first DC circuit to prevent the fault from spreading or causing a safety accident. Examples include: the battery voltage of the stacked battery module exceeds the overvoltage protection threshold; the battery voltage is lower than the undervoltage protection threshold; the battery temperature exceeds the overtemperature protection threshold; the charging and discharging current exceeds the overcurrent protection threshold; the communication connection between the first sub-controller and the main controller is interrupted for more than a preset time; the internal insulation resistance of the stacked battery module drops below the safe value; the battery management system of the stacked battery module detects an internal short circuit, etc.

[0084] A split battery module fault refers to an abnormal state that deviates from normal operating conditions during the operation of the split battery module. It is used to trigger protective operations on the second DC circuit to prevent the fault from spreading or causing a safety accident. Examples include: the battery voltage of the split battery module exceeds the overvoltage protection threshold; the battery voltage is lower than the undervoltage protection threshold; the battery temperature exceeds the overtemperature protection threshold; the charging and discharging current exceeds the overcurrent protection threshold; the communication connection between the second sub-controller and the main controller is interrupted for more than a preset time; the internal insulation resistance of the split battery module drops below the safe value; the battery management system of the split battery module detects an internal short circuit; and the abnormal connection status of the split connection cable causes excessive circuit impedance, etc.

[0085] Disconnection is an operation that breaks the continuity of an electrical circuit to stop the flow of current. It is used to electrically isolate a faulty battery module from the DC bus of the photovoltaic-storage inverter. For example, it can be done by controlling a relay or contactor connected in series in the circuit to disconnect, by controlling a semiconductor switch to turn off, or by commanding the battery management system inside the battery module to disconnect its internal charge / discharge switch, etc.

[0086] Maintaining the continuity of the electrical circuit and allowing the normal flow of current are operations used to ensure that the battery module that has not failed can continue to perform charging or discharging tasks. For example, keeping the relays or contactors connected in series in the circuit closed, keeping the semiconductor switches on, and not sending disconnect commands to the battery management system inside the battery module.

[0087] This embodiment of the specification monitors the operating status of both the stacked and separate battery modules. In the event of a fault in either battery module, a corresponding circuit disconnection operation is performed, while the normal operation of the other battery circuit remains intact. Although the two battery circuits are electrically connected in parallel to the same bus, they are decoupled for fault protection. This prevents the entire energy storage system from collapsing due to a single battery module failure, and fault isolation can be achieved without disassembling the inverter or disconnecting all battery connections. This selective disconnection mechanism allows users to replace or repair faulty battery modules without interrupting system operation, while healthy battery modules can continue to respond to tasks such as photovoltaic charging, load power supply, or grid-connected scheduling. This improves the availability, fault tolerance, and user experience of the home energy storage system, and reduces maintenance costs and downtime losses caused by faults.

[0088] In one optional embodiment of this specification, the photovoltaic-storage inverter further includes a photovoltaic interface and a third DC circuit. The third DC circuit is electrically connected to the photovoltaic interface, which is used for external power connection to the photovoltaic module. The operating state of the photovoltaic-storage inverter also includes a photovoltaic charging state. Monitoring the operating status of the photovoltaic-storage inverter, including: Monitor the photovoltaic input voltage at the photovoltaic interface; When the photovoltaic input voltage is greater than the preset power supply voltage, the operating state is determined to be the photovoltaic charging state; The method also includes: When the photovoltaic charging state is in operation, the photovoltaic interface is controlled to supply power to the stacked battery module and the separate battery module respectively.

[0089] A photovoltaic module is a power generation unit formed by encapsulating solar cells. It is used to convert light energy into DC power and transmit it to a photovoltaic-storage inverter through a photovoltaic interface. Its product forms include monocrystalline silicon photovoltaic panels, polycrystalline silicon photovoltaic panels, thin-film photovoltaic modules, bifacial photovoltaic modules, etc.

[0090] The photovoltaic interface is an input port on the photovoltaic-storage inverter used to connect to the photovoltaic module. It is used to receive the DC power generated by the photovoltaic module and introduce it into the internal circuit of the inverter.

[0091] The photovoltaic interface operating status is a set of parameters characterizing the current operating conditions of the photovoltaic module connected to the photovoltaic interface. It is used to describe the photovoltaic module's power generation capacity, voltage and current characteristics, and interaction with the inverter, such as photovoltaic input voltage value, photovoltaic input current value, photovoltaic instantaneous power, maximum power point tracking status, photovoltaic module temperature, estimated irradiance value, photovoltaic interface connection status, etc.

[0092] The photovoltaic (PV) charging state indicates that the PV module is effectively generating electricity and the voltage meets the supply threshold, thus triggering charging control of the battery module. The PV charging state is typically determined by comparing the PV input voltage with the preset supply voltage. This can be: a PV charging state is determined when the monitored PV input voltage is greater than the preset supply voltage; the state is maintained when the PV input voltage fluctuates but remains stable above the supply threshold; or a mixed state is maintained when at least one of the multiple PV strings meets the voltage condition, etc.

[0093] The photovoltaic input voltage is the DC voltage value that the photovoltaic module transmits to the photovoltaic-storage inverter through the photovoltaic interface. It is used to characterize the power generation capacity and current operating point of the photovoltaic module, such as the open-circuit voltage of the photovoltaic module, the operating voltage of the photovoltaic module when it is in power output state, etc.

[0094] The preset supply voltage is a pre-set voltage threshold used to determine whether the photovoltaic input has the ability to supply power to the battery module. It is used to distinguish whether the photovoltaic module is in an effective power generation state. For example, it is a voltage value set according to the minimum start-up voltage of the photovoltaic-storage inverter, a voltage value set according to the minimum charging voltage requirement of the battery module, or an empirical voltage value determined based on system design experience.

[0095] Power supply refers to the act of simultaneously or time-sharing the electrical energy received by the photovoltaic interface to the stacked battery module and / or the separate battery module. It is used to realize the energy distribution of a single photovoltaic power source to multiple battery circuits, such as simultaneously distributing photovoltaic power to two battery circuits in proportion, charging two battery modules in turn in a time-sharing manner, dynamically adjusting the distribution ratio according to the state of charge of each battery module, and so on.

[0096] This embodiment monitors the photovoltaic input voltage of the photovoltaic interface before monitoring the operating status of the stacked battery module and the separate battery module. When this voltage exceeds a preset supply voltage, the photovoltaic interface is controlled to supply power to the stacked and separate battery modules respectively. This allows the photovoltaic-storage inverter to automatically initiate the charging process for multiple battery modules when photovoltaic power generation is sufficient, avoiding inefficient system operation or startup failure caused by attempting to supply power when sunlight is insufficient or the photovoltaic input voltage is too low. Simultaneously, the separate power supply method allows photovoltaic power to be independently allocated according to the different needs of the two battery modules, achieving simultaneous charging management of the stacked and separate batteries without manual intervention. This improves the self-consumption rate of photovoltaic power generation, reduces grid power consumption, and allows users to expand energy storage capacity using the newly added separate battery interface without disassembling the inverter or modifying the original wiring, further lowering the threshold and cost of system expansion.

[0097] In one optional embodiment of this specification, the photovoltaic-storage inverter further includes a photovoltaic transformer circuit connected in series with a third DC circuit; The photovoltaic interface controls the supply of power to the stacked battery module and the separate battery module, including: The photovoltaic input current input through the photovoltaic interface is boosted to the bus voltage of the photovoltaic-storage inverter; Power is supplied to the stacked battery module and the separate battery module respectively using the bus voltage.

[0098] The photovoltaic transformer circuit is a circuit unit connected to the photovoltaic side circuit that can transform the photovoltaic input voltage. It is used to boost or regulate the voltage input to the photovoltaic interface to match the power supply requirements of the photovoltaic-storage inverter bus voltage. It can be applied in photovoltaic charging conditions, multi-battery module collaborative power supply and other operating scenarios. It can be connected in series on the third DC circuit path to participate in the power transmission and voltage regulation process.

[0099] Boost is an electrical energy conversion process that raises the input voltage to a higher voltage level. It is used to enable the photovoltaic input voltage to meet the requirements of the DC bus voltage so as to achieve power collection on the bus. For example, the low-voltage photovoltaic input can be raised to the high-voltage bus by controlling the switching of the Boost circuit.

[0100] There are several ways to supply power to the stacked battery module and the separate battery module using the bus voltage. These methods include supplying power to the stacked battery module using the bus voltage, supplying power to the separate battery module using the bus voltage, or supplying power to both the stacked battery module and the separate battery module simultaneously using the bus voltage.

[0101] The bus voltage is the voltage on the DC bus inside the photovoltaic-storage inverter. It serves as the reference voltage for energy collection and conversion between different energy ports, such as the photovoltaic interface, the first DC circuit, the second DC circuit, and the AC interface. The photovoltaic-storage inverter uses the bus voltage to uniformly dispatch electrical energy from photovoltaic modules, stacked battery modules, separate battery modules, or voltage source networks. For example, it can boost the photovoltaic input voltage to the bus voltage before supplying power to the battery modules, or it can feed the electrical energy released by the battery modules into the voltage source network or supply the load after bus voltage conversion. The specific value of the bus voltage can be set according to the system configuration, but under different operating modes, the bus voltage may remain relatively stable or fluctuate within a certain range.

[0102] This specification describes an embodiment that incorporates a photovoltaic (PV) transformer circuit within a photovoltaic-storage inverter. When the control PV interface supplies power to the stacked battery module and the separate battery module, this PV transformer circuit boosts the PV input voltage to the inverter's bus voltage and uses this bus voltage to supply power to the two battery circuits. This allows the relatively low and potentially fluctuating voltage output from the PV module to be raised to a unified DC bus voltage level, thus meeting the voltage requirements for battery module charging and providing a voltage matching basis for multiple battery circuits connected in parallel to the same bus. Using the bus voltage as a common supply voltage to supply power to the stacked and separate battery modules avoids the increased cost and structural complexity associated with configuring a separate PV-side boost circuit for each battery circuit. It also allows the stacked and separate batteries to share the same PV power source without needing to distinguish between PV power sources, thereby simplifying the system topology, reducing hardware costs, and improving the flexibility and efficiency of PV power distribution in multi-battery scenarios.

[0103] In one optional embodiment of this specification, a first transformer circuit is provided in the first DC circuit, and a second transformer circuit is provided in the second DC circuit. Before supplying power to the stacked battery module and the separate battery module respectively using the bus voltage, the following is also included: Monitor the voltage of the individual battery modules and / or the voltage of the stacked battery modules of the stacked battery modules respectively; Power is supplied to the stacked battery module and the separate battery module respectively using the bus voltage, including at least one of the following: The second voltage difference between the control bus voltage and the voltage of the separate battery module is based on the second transformer circuit to supply power to the separate battery module. The first voltage difference between the control bus voltage and the stacked battery module voltage is used to supply power to the stacked battery module.

[0104] The first transformer circuit is a voltage conversion unit located in the first DC circuit and connected between the first battery interface and the DC bus of the photovoltaic-storage inverter. It is used to adjust the voltage matching relationship between the stacked battery module and the DC bus. It can be a boost converter, a buck converter, a buck-boost converter, an isolated DC-DC converter, a non-isolated bidirectional converter, etc.

[0105] The second transformer circuit is a voltage conversion unit located in the second DC circuit and connected between the second battery interface and the DC bus of the photovoltaic-storage inverter. It is used to adjust the voltage matching relationship between the separate battery module and the DC bus. It can be a boost converter, buck converter, buck-boost converter, isolated DC-DC converter, non-isolated bidirectional converter, etc.

[0106] The stacked battery module voltage is the terminal voltage value of the stacked battery module itself, used to characterize the current voltage level and state of charge of the stacked battery module. It can be the voltage value of the stacked battery module under different states of charge.

[0107] The voltage of a separate battery module is the terminal voltage value of the separate battery module itself, used to characterize the current voltage level and state of charge of the separate battery module. It can be the voltage value of the separate battery module under different states of charge.

[0108] The first voltage difference is the difference between the bus voltage of the photovoltaic-storage inverter and the voltage of the stacked battery module. It is used as the power source for the drive current to flow into or out of the stacked battery module. For example, it is the positive voltage difference generated when the bus voltage is higher than the voltage of the stacked battery module, and the reverse voltage difference generated when the bus voltage is lower than the voltage of the stacked battery module, etc.

[0109] The second voltage difference is the difference between the bus voltage of the photovoltaic-storage inverter and the voltage of the separate battery module. It is used as the power source for the drive current to flow into or out of the separate battery module. For example, it is the positive voltage difference generated when the bus voltage is higher than the voltage of the separate battery module, and the reverse voltage difference generated when the bus voltage is lower than the voltage of the separate battery module, etc.

[0110] Charging power is the electrical energy corresponding to the rate at which electrical energy flows from the DC bus of the photovoltaic-storage inverter into the battery module through the battery circuit. It describes how quickly the battery module absorbs electrical energy to increase its stored capacity. It can be the charging power of the photovoltaic module to the battery module, or the charging power of the voltage source network on the AC interface to the battery module. It can be measured in kilowatts or nominally in amperes, and can be dynamically adjusted according to the battery's state of charge or current limited according to the soft-start circuit.

[0111] There are several ways to supply power to the separate battery module by controlling the second voltage difference between the bus voltage and the separate battery module voltage based on the second transformer circuit. One way is to configure the second transformer circuit as a step-down converter circuit. When the bus voltage is higher than the separate battery module voltage, the step-down control keeps the second voltage difference within a suitable charging range, thereby enabling power supply from the bus to the separate battery module. Another approach is to configure the second transformer circuit as a boost converter circuit. When the bus voltage is lower than the voltage of the separate battery module, the boost control is used to adjust the second voltage difference to a positive difference value to supply power to the separate battery module. Another approach is to control the second transformer circuit to stop working or switch to standby mode when the second voltage difference is close to zero or reversed, so as to prevent the separate battery module from backflowing power to the bus.

[0112] The principle of supplying power to the stacked battery module based on the first voltage difference between the bus voltage and the stacked battery module voltage controlled by the first transformer circuit is the same as the principle of supplying power to the separate battery module based on the second voltage difference between the bus voltage and the separate battery module voltage controlled by the second transformer circuit. The adjustment of the first voltage difference based on the first transformer circuit can refer to the above-mentioned methods.

[0113] This embodiment of the specification sets up a first transformer circuit in the first DC circuit and a second transformer circuit in the second DC circuit. After monitoring the voltage of the stacked battery module and the voltage of the separate battery module, the transformer circuits in each circuit control the voltage difference between the bus voltage and the battery voltage, thereby independently controlling the charging power flowing through each battery circuit. This allows the two battery circuits to be connected in parallel to the same bus without circulating current or power distribution imbalance, even if the stacked battery module and the separate battery module have different rated voltage levels or are in different states of charge. The method of controlling charging power by voltage difference allows each transformer circuit to independently adjust the equivalent voltage on its respective battery side, thereby achieving decoupled regulation of the charging power of each battery circuit without changing the bus voltage. It eliminates the need to configure an independent bus or additional centralized power distribution unit for each battery module, thereby reducing the system hardware complexity while improving the flexibility and compatibility of multi-battery parallel charging. This allows users to mix and connect battery modules of different specifications, brands, or service lives to the same photovoltaic-storage inverter, further lowering the threshold for system expansion and battery replacement.

[0114] In one optional embodiment of this specification, a first soft-start circuit is further provided in the first DC circuit, and a second soft-start circuit is further provided in the second DC circuit. Based on the operating status of the photovoltaic-storage inverter, the second DC circuit is controlled, including: When the operating state is charging state, the control second DC circuit supplies power to the split battery module via the second soft start circuit; The method also includes: When the operating state is charging, the first DC circuit is controlled to supply power to the stacked battery module via the first soft-start circuit.

[0115] The charging state is an operating condition of a photovoltaic-storage inverter, indicating that the inverter obtains electrical energy from an external power source, such as a voltage source network or photovoltaic modules, and transmits this energy to the individual battery modules for storage via a second DC circuit. In the charging state, the second DC circuit can be configured to allow current to flow towards the individual battery modules, but the charging state does not preclude the possibility of simultaneously charging stacked battery modules or other energy storage devices. Charging states can include photovoltaic charging state, voltage source network charging state, simultaneous charging of two batteries, etc.

[0116] A soft-start circuit is a circuit unit used to limit the inrush current during the initial connection of the battery module. It can be set in series in the battery circuit to control the rate of current rise or limit the current amplitude during the initial stage of the bus voltage supplying power to the battery module. Examples include a resistive current limiting circuit composed of a soft-start resistor and a bypass switch in series, an electronic soft-start circuit composed of a semiconductor switch and a current limiting resistor, and a current ramp-up circuit composed of an inductor and a switching transistor.

[0117] The first soft-start circuit is a circuit unit connected in series in the first DC circuit to limit the inrush current during the initial connection or startup of the stacked battery module, and to protect the switching devices and bus capacitors inside the stacked battery module and inverter from instantaneous large current surges.

[0118] The second soft-start circuit is a circuit unit connected in series in the second DC circuit to limit the inrush current during the initial connection or startup of the split battery module. It is used to protect the switching devices and bus capacitors inside the split battery module and inverter from instantaneous high current surges.

[0119] This embodiment of the specification sets up soft-start circuits in the first DC circuit and the second DC circuit respectively. When supplying power to the stacked battery module and the separate battery module with the bus voltage, the bus voltage is delivered to the battery module through the soft-start circuit of each circuit. This allows the two battery circuits to independently complete the current-limited pre-charging process in the initial stage of charging by connecting to the bus, avoiding instantaneous inrush current caused by a large voltage difference between the bus voltage and the battery voltage. This protects the battery management system and cells inside the battery module, as well as the switching devices and bus capacitors inside the inverter. By setting up soft-start circuits separately, the two battery circuits can independently complete the soft start at their respective appropriate time points without waiting for the other circuit to complete pre-charging before starting power supply in their own circuit. For example, the stacked battery module can start soft start immediately after connection, while the separate battery module can start its soft start process independently when connected later, or the two circuits can execute their respective soft start processes in parallel without interfering with each other. This improves the power supply flexibility and system response speed in multi-battery access scenarios and reduces the start-up delay caused by pre-charging timing coupling and mutual waiting that may be caused by sharing the soft-start circuit.

[0120] In one optional embodiment of this specification, the second soft-start circuit includes a soft-start input terminal, a soft-start output terminal, a soft-start resistor, a soft-start switch connected in series with the soft-start resistor, and a bypass switch connected in parallel in the second soft-start circuit. Power is supplied to the separate battery module via a second soft-start circuit, including: Close the soft start switch and open the bypass switch. Based on the charging current of the soft start output terminal limited by the soft start resistor, obtain the limiting current of the soft start output terminal. Power is supplied to the separate battery module according to the current limit; When the charging current drops to the preset current threshold, the bypass switch is closed and the soft start switch is opened to supply power to the separate battery module according to the charging current.

[0121] A soft-start switch is a switching device connected in series with a soft-start resistor to control whether the soft-start resistor is connected to the battery circuit. It is used to turn on the soft-start resistor in the initial stage of soft-start to allow current to flow through the soft-start resistor for current-limited pre-charging, and to turn off the soft-start resistor after the soft-start is completed to disconnect the soft-start resistor from the circuit. Examples of soft-start switches include mechanical switches, relays, contactors, semiconductor field-effect transistors, transistors, thyristors, etc.

[0122] A bypass switch is a switching device connected in parallel with a soft-start resistor to bypass the soft-start resistor from the battery circuit after the soft start is completed. It is used to reduce the energy loss caused by the continuous current flowing through the soft-start resistor and restore the low impedance state of the normal path. Examples of bypass switches include mechanical switches, relays, contactors, semiconductor field-effect transistors, transistors, thyristors, etc.

[0123] The limiting current is the current value obtained by limiting the amplitude of the charging current of the battery circuit by the soft-start resistor in the initial stage of soft start. It is used to avoid instantaneous inrush current caused by excessive voltage difference between the bus voltage and the battery voltage during the pre-charging process, thereby protecting the battery module and internal components of the inverter. For example, the soft-start resistor limits the charging current to a current limit value within a preset safe range.

[0124] A soft-start resistor is a resistive element used to limit the initial inrush current during circuit startup. It is connected in series in the power supply circuit when the soft-start circuit is operating, reducing the instantaneous current amplitude during startup through its current-limiting effect. Examples of soft-start resistors include, but are not limited to, fixed-value power resistors, positive temperature coefficient thermistors, and adjustable resistors. In the second DC circuit of a photovoltaic-storage inverter, the soft-start resistor can be connected in series with a soft-start switch. When the bypass switch is open, the charging current flows to the individual battery modules through the soft-start resistor. Once the charging current drops to a preset threshold, the soft-start resistor can be short-circuited by the bypass switch to reduce losses.

[0125] This embodiment of the specification configures a second soft-start circuit including a soft-start resistor, a soft-start switch, and a bypass switch. When the battery is charging, the soft-start switch is closed and the bypass switch is opened first, so that the charging current flows through the soft-start resistor to limit the initial inrush current. After the charging current drops to a preset current threshold, the bypass switch is closed and the soft-start switch is opened to cut off the bypass of the soft-start resistor and restore the normal low-impedance charging path. This allows the split battery module to automatically complete the complete process of soft-start current limiting and bypass switching during connection or startup. This effectively avoids instantaneous inrush current caused by excessive voltage difference between the bus voltage and battery voltage, protecting the battery management system and cells inside the separate battery module, as well as the switching devices and bus capacitors inside the inverter. Simultaneously, by monitoring the charging current to drop to a preset threshold before bypass switching, it ensures that the current-limiting resistor is removed only after sufficient pre-charging, avoiding secondary impacts caused by premature bypass and improving the reliability and safety of the soft-start process. After soft-start, the bypass switch remains closed and the soft-start switch remains open, completely removing the soft-start resistor from the circuit, eliminating energy loss caused by continuous current flow, and improving system efficiency under normal operating conditions.

[0126] In one optional embodiment of this specification, the AC interface is further used to connect a load to the photovoltaic-storage inverter. In response to the load connected to the AC interface, the stacked battery module supplies power to the load via the AC interface, including: In response to the AC interface being connected to a load, the system checks whether the bus voltage of the photovoltaic-storage inverter is greater than the standard startup voltage of the stacked battery module. If so, the stacked battery module is started with the bus voltage, and the stacked battery module supplies power to the connected load through the AC interface; If not, the stacked battery module is started with the standard startup voltage, and the stacked battery module supplies power to the connected load via the AC interface.

[0127] The connected load is an electrical device that is connected to the photovoltaic-storage inverter via an AC interface and consumes electrical energy. It is used to convert the AC power obtained from the inverter into other forms of energy for terminal use. These forms may include, but are not limited to, household appliances, lighting equipment, power tools, charging piles, and industrial equipment.

[0128] At least one of the following is a statement indicating that one or more of the listed power supply methods can be selected for execution, which allows the photovoltaic-storage inverter to flexibly select a power supply strategy according to actual operating conditions and battery status, such as selecting to supply power only to the stacked battery modules, selecting to supply power only to the separate battery modules, selecting to supply power to two battery modules simultaneously, or dynamically switching the power supply method according to the load power, etc.

[0129] The embodiments in this specification, in response to load access events at the AC interface before separately monitoring the operating status of the stacked battery modules and the individual battery modules, allow the stacked battery modules, the individual battery modules, or both to supply power to the accessed load through the AC interface individually. This enables the photovoltaic-storage inverter to automatically select the optimal power supply strategy based on the actual load demand and the availability of each battery module, without requiring manual configuration or switching of battery circuits by the user. Supporting single-battery module power supply allows the system to maintain load power supply even when another battery module fails, is not connected, or has insufficient power, improving the system's fault tolerance and availability. Supporting dual-battery module power supply allows the system to simultaneously release the energy stored in both battery modules to meet the instantaneous or continuous power demand of high-power loads, overcoming the limitation of the limited discharge power of a single battery module. By performing power supply decisions before separately monitoring the operating status, the system can respond quickly when a load is connected without waiting for a complete battery status scan, thereby shortening the load power-on waiting time and improving the user's power experience and system response speed.

[0130] In one optional embodiment of this specification, the AC interface is also used to connect a load, and the method further includes at least one of the following: In response to a load being connected to the AC interface, the stacked battery module supplies power to the load through the AC interface; In response to a load being connected to the AC interface, the separate battery module supplies power to the load through the AC interface; In response to the AC interface being connected to a load, the stacked battery module and the separate battery module supply power to the load through the AC interface.

[0131] A load is a device or apparatus that is connected to the AC or DC interface of a photovoltaic-storage inverter and consumes electrical energy. It is used to convert the electrical energy obtained from the photovoltaic-storage inverter into other forms of energy for user use, such as household appliances, lighting equipment, power tools, charging piles, industrial equipment, electric heaters, air conditioners, DC motors, etc.

[0132] The AC interface can be equipped with an inverter circuit. When supplying power to the load through stacked battery modules, separate battery modules, or a combination of stacked and separate battery modules, the inverter circuit can change the current form, adjust the supply voltage, and adjust the supply current according to the actual situation of the load.

[0133] The AC interface is an input / output port on the photovoltaic-storage inverter used to connect to a voltage source network or AC load, enabling bidirectional power exchange between the inverter and the AC side. Examples include standardized AC terminals, waterproof AC connectors, grid-connected interfaces with relay control, pluggable AC connectors, threaded fastening terminals, and so on.

[0134] Power supply refers to the process by which a battery module releases the electrical energy it stores, converts it through a photovoltaic-energy storage inverter, and then transmits it to the load via an AC interface. This enables the load to obtain the electrical energy required for operation from the energy storage system. For example, stacked battery modules can discharge and then be converted into AC power by an inverter circuit to supply household appliances; separate battery modules can discharge and supply power to power tools; and two battery modules can discharge simultaneously to meet the power demand of a high-power air conditioner, etc.

[0135] The solutions provided in the embodiments of this specification, in response to the connection of a load via the AC interface, allow the stacked battery modules, individual battery modules, or both to supply power to the load through the AC interface. This enables the photovoltaic-storage inverter to automatically select the optimal power supply strategy based on the actual load demand and the availability of each battery module, without requiring manual configuration or switching of battery circuits by the user. Supporting single-battery module power supply allows the system to maintain load power supply even when another battery module fails, is not connected, or has insufficient power, improving the system's fault tolerance and availability. Supporting dual-battery module power supply allows the system to simultaneously release the energy stored in both battery modules to meet the instantaneous or continuous power demand of high-power loads, overcoming the limitation of the limited discharge power of a single battery module. By making power supply decisions in advance and responding quickly when the load is connected, the waiting time for the load to power on is shortened, improving the user's power experience and the system's response speed.

[0136] In one optional embodiment of this specification, the photovoltaic-storage inverter further includes a main controller, which is used to control a first sub-controller configured in a stacked battery module and a second sub-controller configured in a split battery module. Monitoring the operating status of the photovoltaic-storage inverter, including: The main controller monitors the operating status of the stacked battery module based on the first sub-controller and monitors the operating status of the split battery module based on the second sub-controller. Based on the operating status of the photovoltaic-storage inverter, the second DC circuit is controlled, including: The main controller sends a second control command to the second sub-controller based on the operating status of the photovoltaic-storage inverter to control the second DC circuit; The method also includes: The main controller sends a first control command to the first sub-controller based on the operating status of the photovoltaic-storage inverter to control the first DC circuit.

[0137] The main controller is the core control unit located inside the photovoltaic-storage inverter. It is used to coordinate and manage the operation of the entire photovoltaic-storage system, including receiving the operating status information of each battery module, generating charging and discharging power control commands, and scheduling photovoltaic input and grid-connected output. Examples of main controllers include microcontrollers, digital signal processors, embedded control chips, programmable gate arrays, etc.

[0138] The main controller can establish bidirectional communication links with the first and second sub-controllers respectively. These communication links can be implemented through a communication bus and the first and second communication interfaces. The sub-controllers are responsible for monitoring the operating status of their respective battery modules and reporting it to the main controller. The main controller generates corresponding control commands based on the received operating status information and then sends the control commands to the sub-controllers through the communication bus and their respective communication interfaces. After receiving the commands, the sub-controllers execute the corresponding power adjustment actions, thereby realizing the coordinated control of multiple distributed battery modules by the main controller, which combines centralized decision-making with distributed execution.

[0139] The first sub-controller is a local control unit located inside the stacked battery module. It is used to monitor the operating status of the stacked battery module and receive control commands from the main controller to perform charging and discharging power regulation. Examples include the management chip in the battery management system, the slave controller in the battery module, the slave station device that communicates with the main controller, the microcontroller integrated on the battery module interface board, etc.

[0140] The second sub-controller is a local control unit located inside the split battery module. It is used to monitor the operating status of the split battery module and receive control commands from the main controller to perform charging and discharging power regulation. Examples include the management chip in the battery management system, the slave controller in the battery module, the slave station device that communicates with the main controller, the microcontroller integrated on the split battery interface board, etc.

[0141] This specification's embodiments configure a first sub-controller and a second sub-controller for the stacked battery module and the separate battery module, respectively, in addition to the main controller. The sub-controllers monitor their own battery module's operating status, and the main controller sends control commands to the sub-controllers based on the received status information. This achieves a control architecture combining distributed monitoring and centralized decision-making. The sub-controller-based monitoring of their respective battery module operating status allows status acquisition to be completed locally within the battery module, reducing noise and attenuation introduced by long-distance analog signal transmission and improving the accuracy and reliability of the monitoring data. The main controller's method of sending control commands to the sub-controllers based on the received operating status enables centralized power regulation decision-making. Located on the inverter side, this facilitates the coordination of power distribution among photovoltaic input, load output, and multiple battery modules. Simultaneously, specific power execution actions are delegated to the sub-controllers to complete locally within the battery modules, avoiding the complex wiring requirements of the main controller directly controlling the switching devices in each battery circuit. This master-slave control architecture allows stacked battery modules and separately connected battery modules to use their own independent sub-controllers to achieve standardized communication interfaces. This enables battery modules from different manufacturers, with different specifications and communication protocols to connect to the same photovoltaic-storage inverter by adapting to the sub-controllers, thereby improving the system's openness and scalability, and reducing the integration difficulty for users when mixing battery modules from different brands.

[0142] In one optional embodiment of this specification, the photovoltaic-storage inverter further includes a communication bus that is communicatively connected to the main controller. The communication bus is connected to a first communication interface for communicating with the stacked battery module and a second communication interface for communicating with the separate battery module. Based on the operating status of the photovoltaic-storage inverter, the main controller sends a second control command to the second sub-controller to control the second DC circuit, including: Based on the operating status of the photovoltaic-storage inverter, the main controller sends a second control command to the second sub-controller via the communication bus and the second communication interface to control the second DC circuit. The main controller sends a first control command to the first sub-controller based on the operating status of the photovoltaic-storage inverter to control the first DC circuit, including: Based on the operating status of the photovoltaic-storage inverter, the main controller sends a first control command to the first sub-controller via the first communication interface through the communication bus to control the first DC circuit.

[0143] The communication bus is a communication line in a photovoltaic-storage inverter used to transmit data or commands between the main controller and the sub-controllers of the battery modules. It is used for functions such as monitoring operating status, issuing control commands, and transmitting fault information. Examples of communication buses include, but are not limited to, CAN bus, RS485 bus, I2C bus, Ethernet, etc. The communication bus may have a first communication interface and a second communication interface, used for communication with the first sub-controller in the stacked battery module and the second sub-controller in the separate battery module, respectively. The specific topology or protocol of the communication bus may vary depending on the system configuration.

[0144] The first communication interface is a communication port located on the photovoltaic-storage inverter, used for data exchange with the first sub-controller of the stacked battery module. It is used to establish an information transmission channel between the main controller and the first sub-controller, such as a controller area network bus interface, RS485 serial communication interface, Ethernet interface, wireless communication module interface, etc.

[0145] The second communication interface is a communication port located on the photovoltaic-storage inverter, used for data exchange with the second sub-controller of the split battery module. It is used to establish an information transmission channel between the main controller and the second sub-controller, such as a controller area network bus interface, RS485 serial communication interface, Ethernet interface, wireless communication module interface, etc.

[0146] Communication is the process of data exchange between the main controller and the sub-controller through a communication interface and transmission medium. It is used to transmit operating status information, control commands, handshake signals or fault alarms between the main controller and the sub-controller. This includes the main controller reading the battery voltage and state of charge reported by the sub-controller through the communication interface, the sub-controller receiving the charging current control command issued by the main controller through the communication interface, and the main controller and the sub-controller confirming that the communication link is normal through a handshake protocol, etc.

[0147] This embodiment of the specification establishes a first communication interface for communicating with stacked battery modules and a second communication interface for communicating with individual battery modules within the photovoltaic-energy storage inverter. The main controller sends a first control command to a first sub-controller via the first communication interface and a second control command to a second sub-controller via the second communication interface. This allows the main controller to establish independent communication channels with both the stacked and individual battery modules, preventing interference or competition between their communication signals on the same bus. The independent communication interfaces allow the stacked and individual battery modules to use different communication protocols or rates to access the same photovoltaic-energy storage inverter, thus improving the system's compatibility with battery modules from different manufacturers and generations. Furthermore, the independent communication interfaces enable the main controller to maintain normal communication and control with healthy battery modules even if one communication interface fails or is interrupted, preventing system failure due to a single point of failure and improving the system's communication reliability and fault tolerance.

[0148] Corresponding to the control method of the photovoltaic-storage inverter described above, this specification also provides a photovoltaic-storage inverter and a photovoltaic-storage system. Taking the accompanying drawings as examples, the photovoltaic-storage inverter and the photovoltaic-storage system will be further described in detail: Figure 2 This specification provides a schematic diagram of the structure of a photovoltaic-storage inverter according to one embodiment, specifically: The photovoltaic-storage inverter 1 includes a photovoltaic transformer circuit 12, an inverter circuit 13, an AC interface 14, an inverter DC bus 15, a main controller 16, a first battery interface 17, a second battery interface 18, a photovoltaic interface 19, a communication bus 41, a first communication interface 42, and a second communication interface 43. The photovoltaic-storage inverter 1 includes an AC interface 14, a first battery interface 17, a second battery interface 18, a first DC circuit, and a second DC circuit. The AC interface 14 is used to electrically connect to a voltage source network. The first DC circuit is electrically connected to the first battery interface 17, which is used to electrically connect to the stacked battery module 2. The second DC circuit is electrically connected to the second battery interface 18, which is used to electrically connect to the split battery module 3. Among them, the voltage source network is electrically connected to the photovoltaic-storage inverter 1 through the AC interface 14, the stacked battery module 2 is electrically connected to the photovoltaic-storage inverter 1 through the first battery interface 17 to form a first DC circuit, and the split battery module 3 is electrically connected to the photovoltaic-storage inverter 1 through the second battery interface 18 to form a second DC circuit.

[0149] Among them, the photovoltaic interface 19 is used to electrically connect the photovoltaic module 11 to the photovoltaic-storage inverter 1, the voltage source network is electrically connected to the photovoltaic-storage inverter 1 through the AC interface 14, the stacked battery module 2 is electrically connected to the photovoltaic-storage inverter 1 through the first battery interface 17 to form a first DC circuit, and the split battery module 3 is electrically connected to the photovoltaic-storage inverter 1 through the second battery interface 18 to form a second DC circuit.

[0150] The third DC circuit is electrically connected to the photovoltaic interface 19, which is used to connect the photovoltaic module 11 to the external power supply. The photovoltaic module 11 is electrically connected to the photovoltaic-storage inverter 1 through the photovoltaic interface 19 to form a photovoltaic circuit.

[0151] The electrical connection between the photovoltaic module 11 and the photovoltaic-storage inverter 1 via the photovoltaic interface 19 can be achieved in, but is not limited to, the following ways: connecting via a standardized photovoltaic connector and a photovoltaic-specific cable; connecting via a terminal block and screw fastening; connecting via an aviation plug and a shielded cable; connecting via a quick-connect connector and a prefabricated cable assembly; aggregating via a combiner box and connecting in a single or multiple manner; or connecting multiple photovoltaic strings in parallel via a branch connector. It should be noted that there can be multiple photovoltaic modules, and similarly, there can be multiple electrical connections between the photovoltaic module 11 and the photovoltaic-storage inverter 1 via the photovoltaic interface 19, and correspondingly, multiple photovoltaic transformer circuits 12 connected in series in the electrical connections. The photovoltaic circuit is the electrical path in the photovoltaic-storage inverter 1 consisting of the photovoltaic interface 19, the third DC circuit, and possibly the photovoltaic transformer circuits 12, used to transmit the electrical energy generated by the photovoltaic module 11 to the inside of the photovoltaic-storage inverter, such as the inverter DC bus 15. The photovoltaic circuit may simultaneously supply power to the stacked battery module 2 or the separate battery module 3 under specific operating modes.

[0152] The electrical connection between the voltage source network and the photovoltaic-storage inverter 1 via AC interface 14 can be achieved in various ways, including but not limited to: direct connection to the mains cable via standard AC terminals; indirect connection to the household power distribution line via a circuit breaker or residual current device (RCD); connection to the grid cable via an industrial connector with a locking mechanism; connection to the AC distribution box lead-out line via crimp terminals in the junction box; connection via a dedicated grid-connected AC switch box; rapid off-grid / grid-connected switching via a pluggable AC connector; and parallel connection to multiple AC inputs via a busbar. It should be noted that there can be multiple voltage source networks and electrical loads, and correspondingly, multiple electrical connections can be formed between the voltage source network and the photovoltaic-storage inverter 1 via AC interface 14.

[0153] The AC interface 14 can be connected to a voltage source network to achieve grid-connected power supply or to draw power from the grid. It can also be directly connected to AC loads (such as household appliances, lighting equipment, power tools, etc.) to supply power. In addition, it can be used to connect multiple inverters in parallel on the AC side, connect wind turbines and other AC power sources, or connect step-up transformers in large power plants to connect to medium and high voltage power grids.

[0154] The inverter DC bus 15 is a common DC voltage node located inside the photovoltaic-storage inverter 1. It is used to collect the bidirectional power from the DC power boosted by the photovoltaic transformer circuit 12 through the photovoltaic interface 19, the first DC circuit connected to the first battery interface 17, and the second DC circuit connected to the second battery interface 18. It distributes the DC power to the inverter circuit 13 for DC-AC conversion, or receives the DC power rectified by the inverter circuit 13 to supply power to the battery circuit. Each power port is connected to the bus in parallel to achieve unified energy scheduling and balance.

[0155] The main controller 16 is the core control unit located inside the photovoltaic-storage inverter 1. It coordinates and manages the operation of the entire photovoltaic-storage system, including receiving operating status information from the stacked battery modules 2 and the separate battery modules 3, generating charging and discharging power control commands, and scheduling photovoltaic input and grid-connected output. Components include microcontrollers, digital signal processors, embedded control chips, and field-programmable gate arrays. Figure 2 In this process, the main controller 16 communicates with other devices through the communication bus 41, the first communication interface 42, and the second communication interface 43.

[0156] Figure 3 This is a schematic diagram of the structure of a photovoltaic energy storage system provided in one embodiment of this specification, specifically: The photovoltaic-storage system 6 includes a photovoltaic-storage inverter 1, a stacked battery module 2, and a separate battery module 3. The photovoltaic-storage inverter 1 includes a photovoltaic module 11, a photovoltaic transformer circuit 12, an inverter circuit 13, an AC interface 14, an inverter DC bus 15, a main controller 16, a first battery interface 17, a second battery interface 18, a communication bus 41, a first communication interface 42, and a second communication interface 43. The stacked battery module 2 includes a first sub-controller 21, a transformer circuit 22, and a battery 23. The separate battery module 3 includes a second sub-controller 31, a transformer circuit 22, and a soft-start circuit 32. Furthermore, in some cases, the photovoltaic-storage system may also include a photovoltaic module and a voltage source network.

[0157] Among them, the stacked battery module 2 is electrically connected to the photovoltaic-energy storage inverter 1 to form a first DC circuit; the split battery module 3 is electrically connected to the photovoltaic-energy storage inverter 1 to form a second DC circuit.

[0158] Photovoltaic interface 19 is used to connect photovoltaic module 11. Photovoltaic transformer circuit 12 is connected between photovoltaic interface 19 and inverter DC bus 15. Inverter circuit 13 is connected between inverter DC bus 15 and AC interface 14. AC interface 14 is used to connect to voltage source network or AC load. First battery interface 17 is used to connect to stacked battery module 2. Second battery interface 18 is used to connect to split battery module 3. First battery interface 17 and second battery interface 18 are connected in parallel to inverter DC bus 15. The first communication interface 42 is associated with the first battery interface 17 and is used to communicate with the stacked battery module 2. The second communication interface 43 is associated with the second battery interface 18 and is used to communicate with the separate battery module 3. The first communication interface 42 and the second communication interface 43 are respectively connected to the main controller 16 through the communication bus 41. The main controller 16 is used to obtain the operating status of the stacked battery module 2 through the first communication interface 42 and to obtain the operating status of the separate battery module 3 through the second communication interface 43. The main controller 16 is also used to send a first control command to the stacked battery module 2 through the first communication interface 42 and to send a second control command to the separate battery module 3 through the second communication interface 43.

[0159] The first battery interface 17 is connected to the stacked battery module 2 via a first DC circuit, and the second battery interface 18 is connected to the separate battery module 3 via a second DC circuit. The first DC circuit and the second DC circuit are connected to the inverter DC bus 15 in parallel or series, respectively. The photovoltaic module 11 is connected to the inverter DC bus 15 via a photovoltaic transformer circuit 12, and the inverter circuit 13 is connected between the inverter DC bus 15 and the AC interface 14. The main controller 16 is communicatively connected to the first sub-controller 21 and the second sub-controller 31, respectively. When the photovoltaic module 11 generates DC power, the photovoltaic transformer circuit 12 is used to boost the photovoltaic input voltage to the bus voltage of the inverter DC bus 15; the stacked battery module 2 and the split battery module 3 are used to discharge to the inverter DC bus 15 or draw power from the inverter DC bus 15 for charging through their respective battery circuits; the inverter circuit 13 is used to convert the DC power on the inverter DC bus 15 into AC power and supply power to the connected load through the AC interface 14, or to rectify the AC power connected to the AC interface 14 and feed it into the inverter DC bus 15; the main controller 16 is used to monitor the operating status of the stacked battery module 2 and the split battery module 3 respectively, and control the charging and discharging power flowing through the first DC circuit and the second DC circuit according to the operating status.

[0160] The photovoltaic-storage inverter 1 is used to monitor the operating status of the stacked battery module and the separate battery module respectively; according to the operating status of the stacked battery module, it controls the charging and discharging power flowing through the first DC circuit; according to the operating status of the separate battery module.

[0161] The photovoltaic-storage inverter 1 is used in this photovoltaic-storage system to realize centralized control of photovoltaic power generation management, battery energy storage management, and AC grid connection / load power supply. Its function is to provide users with a flexible and expandable core energy storage device that can be expanded online without disassembling the inverter. It controls the charging and discharging power flowing through the second DC circuit so that when the power demand increases, it can connect new battery modules through the split interface without modifying the installed stacking structure and AC lines, thereby reducing expansion costs and labor input. Specifically, the photovoltaic-storage inverter 1 can be an integrated unit comprising the following components: a photovoltaic module 11, with a photovoltaic interface 19 for connecting to the photovoltaic module; a photovoltaic transformer circuit 12 for boosting the photovoltaic input voltage to the bus voltage; an inverter circuit 13 for realizing bidirectional conversion between DC and AC; an AC interface 14 for connecting to a voltage source network or AC load; an inverter DC bus 15, serving as a common voltage reference point for each power port; a main controller 16, serving as the decision-making core of the system; a first battery interface 17, a stacking plug-in interface for connecting to stacked battery modules; and a second battery interface 18, a non-stacked interface for connecting to separate battery modules.

[0162] The first DC circuit formed by the stacked battery module 2 and the photovoltaic-storage inverter 1 through the first battery interface 17 may include, but is not limited to: direct electrical conduction between the stacked battery and the inverter through a plug-in connection via an aviation plug; push-in installation of the battery module by connecting to a plug-in battery unit via a rack backplane connector; rigid overlap by busbar and bolt fastening; connection by elastic contact terminals and planar solder pads; and series or parallel expansion between multiple battery modules by a cascade connector dedicated to multi-layer stacking. The stacked battery module 2 may include multiple expandable batteries and corresponding expansion devices.

[0163] The second DC circuit formed by the split battery module 3 and the photovoltaic-storage inverter 1 through the second battery interface 18 can include, but is not limited to: connection via plug-in terminals directly mounted on the chassis for quick plugging and unplugging without additional cables; connection via pluggable terminal blocks with multi-core flexible wires; connection via quick-connect connectors and flexible cables; connection via pre-fabricated power cables with connectors; connection via industrial connectors with locking mechanisms and cable assemblies; connection via crimp terminals in the junction box to cables led out from the split battery; connection via spring-loaded crimp terminals to multi-strand flexible cables, etc. Similarly, the split battery module 3 can include multiple expandable batteries and corresponding expansion devices.

[0164] In some embodiments, a transformer circuit and / or a soft-start circuit are also provided in the first DC circuit, and a transformer circuit and / or a soft-start circuit are also provided in the second DC circuit to support the mixed access of battery modules of different voltage levels and soft-start protection. In terms of installation, the photovoltaic-energy storage inverter 1 can be deployed in a wall-mounted or floor-standing manner. The stacked battery modules 2 are directly stacked on top of or below the inverter to form an integrated structure via a stacking and plugging method, while the separate battery modules 3 are separately arranged from the inverter via cables. Each battery module can be installed, disassembled, or replaced independently, with clear and simple external wiring and no obvious redundant cable provisions. It can also be designed as a modular expansion scheme, for example, making the first battery interface 17 and the second battery interface 18 into standardized interface forms to facilitate the access of battery modules of different brands or specifications. This embodiment does not impose any limitations on this. The photovoltaic-energy storage inverter 1 can achieve compatible access, independent monitoring, and decoupled control of stacked and separate batteries, becoming a key device supporting flexible expansion and high reliability of residential energy storage systems.

[0165] The photovoltaic-storage inverter provided in this specification, through the provision of a first battery interface and a second battery interface, wherein the first battery interface is used to form a stacked plug-in connection with stacked battery modules, and the second battery interface is used to form a separate connection with separate battery modules, enables the photovoltaic-storage inverter to be compatible with both stacked and separate battery modules, eliminating the need to configure different types of inverters for battery modules with different installation methods; by connecting the first DC circuit and the second DC circuit in parallel to the inverter's DC bus, the two battery modules can share the same bus while maintaining an electrical parallel relationship, providing a basis for subsequent independent control and decoupled operation. Topology foundation: When users need to expand battery capacity, there is no need to disassemble the installed stacked battery modules or modify the fixed AC power distribution lines. Online capacity expansion can be completed simply by connecting the newly added split battery module through the second battery interface, avoiding the labor costs and resource waste caused by inverter disassembly and wiring modifications. The independent setting of the two battery interfaces allows the stacked battery modules and split battery modules to be arranged separately in physical structure. The stacked battery modules form an integrated structure with the inverter to save installation space, while the split battery modules can be flexibly placed in remote locations according to site conditions, thereby improving the adaptability and layout flexibility of the home energy storage system in different installation scenarios.

[0166] Figure 4 This is a schematic diagram of another optical energy storage system provided in one embodiment of this specification, specifically: The photovoltaic-storage system 6 includes a photovoltaic-storage inverter 1, a stacked battery module 2, and a separate battery module 3. The photovoltaic-storage inverter 1 includes a photovoltaic module 11, a photovoltaic transformer circuit 12, an inverter circuit 13, an AC interface 14, a DC bus 15, a main controller 16, a first battery interface 17, a second battery interface 18, and a photovoltaic interface 19. The stacked battery module 2 includes a first sub-controller 21, a transformer circuit 22, a battery 23, and a soft-start circuit 32. The separate battery module 3 includes a battery 23, a transformer circuit 22, a second sub-controller 31, and a soft-start circuit 32. The first DC circuit and the second DC circuit are respectively connected in series with a soft-start circuit 32.

[0167] The photovoltaic interface 19 is used to connect the photovoltaic module. The inverter circuit 13 is connected between the inverter DC bus 15 and the AC interface 14. The AC interface 14 is used to connect the voltage source network or AC load. The first battery interface 17 is used to connect to the stacked battery module 2 in a stacked plug-in connection to form a first DC circuit. The second battery interface 18 is used to connect to the split battery module 3 separately to form a second DC circuit. The first battery interface 17 and the second battery interface 18 are respectively connected in parallel to the inverter DC bus 15.

[0168] Transformer circuit 22 is located inside stacked battery module 2 and connected in series in the first DC circuit between battery 23 and first battery interface 17. It is used to adjust the voltage matching relationship between stacked battery module 2 and inverter DC bus 15. Similarly, soft start circuit 32 is located inside stacked battery module 2 and connected in series in the first DC circuit between battery 23 and first battery interface 17. It is used to limit the inrush current when battery 23 is connected to inverter DC bus 15. Transformer circuit 22 is located inside split battery module 3 and connected in series in the second DC circuit between battery 23 and first battery interface 17. It is used to adjust the voltage matching relationship between split battery module 3 and inverter DC bus 15. Similarly, soft start circuit 32 is located inside split battery module 3 and connected in series in the second DC circuit between battery 23 and first battery interface 17. It is used to limit the inrush current when battery 23 is connected to inverter DC bus 15.

[0169] The soft-start circuit 32 can be connected in various ways, such as... Figure 7 This is a circuit diagram of a soft-start circuit provided as an embodiment of the present specification.

[0170] See Figure 7 , Figure 7This is a circuit diagram of a soft-start circuit provided in one embodiment of this specification. The soft-start circuit 32 is connected in series in the electrical connection between the inverter DC bus 15 and the first battery interface 17 and the second battery interface 18. One end of the soft-start circuit 32 is connected to the second battery interface 18, and the other end is connected to the inverter DC bus 15. The soft-start circuit 32 is disposed inside the photovoltaic-storage inverter.

[0171] like Figure 8 This is a circuit diagram of yet another soft-start circuit provided in one embodiment of this specification.

[0172] See Figure 8 A soft-start circuit 32 is connected in series between the second battery interface 18 and the inverter DC bus 15. Figure 7 The difference lies in the series connection position of the soft-start circuit 32 in the loop; it only operates between the second battery interface 18 and the inverter DC bus 15. This connection method indicates that the soft-start circuit 32 can be positioned closer to the second battery interface 18.

[0173] like Figure 9 This is a circuit diagram of another soft-start circuit provided as an embodiment of the present specification.

[0174] See Figure 9 A soft-start circuit 32 is connected in series between the second battery interface 18 and the inverter DC bus 15.

[0175] Figure 9 In the process, a soft-start circuit 32 is connected in series between the second battery interface 18 and the inverter DC bus 15, and another soft-start circuit 32 is also connected in series between the first battery interface 17 and the inverter DC bus 15.

[0176] The second battery interface 18 is used to connect the split battery module, and the first battery interface 17 is used to connect the stacked battery module. The two soft-start circuits 32 are connected in series in the second DC circuit and the first DC circuit, respectively, and are used to limit the inrush current when their respective battery modules are connected.

[0177] This connection method indicates that the first DC circuit and the second DC circuit are each independently equipped with a soft start circuit 32. The two soft start circuits 32 can have the same or different electrical parameters, and can work simultaneously or independently without interfering with each other.

[0178] There are various architectures for soft-start circuits, such as... Figure 10 , Figure 10 This is a schematic diagram of the architecture of a soft-start circuit provided in one embodiment of this specification.

[0179] The soft-start circuit includes a soft-start circuit input terminal 51, a soft-start circuit output terminal 52, a controllable mechanical switch 53, and a soft-start resistor 54; The soft-start circuit input terminal 51 is used to receive electrical energy from the inverter DC bus, and the soft-start circuit output terminal 52 is used to output current-limited electrical energy to the battery module. The upper controllable mechanical switch 53 and the soft-start resistor 54 are connected in parallel. One end of the upper controllable mechanical switch 53 is connected to the soft-start circuit input terminal 51, and the other end is connected to the soft-start circuit output terminal 52. At the same time, the lower controllable mechanical switch 53 and the soft-start resistor 54 are connected in series. One end of the soft-start resistor 54 is connected to the lower controllable mechanical switch 53, and the other end is connected to the soft-start circuit output terminal 52. During the soft start process, the lower controllable mechanical switch 53 is in the open state and the upper controllable mechanical switch 53 is in the closed state. Current flows through the soft start resistor 54 for current-limited pre-charging. After the pre-charging is completed, the lower controllable mechanical switch 53 is closed, and the soft start resistor 54 is bypassed to reduce path loss.

[0180] See Figure 11 , Figure 11 This is a schematic diagram of another soft-start circuit provided in one embodiment of this specification. The soft-start circuit includes a soft-start circuit input terminal 51, a soft-start circuit output terminal 52, a controllable mechanical switch 53, a soft-start resistor 54, and a semiconductor switch 55; The soft-start circuit input terminal 51 is used to receive electrical energy from the inverter DC bus, and the soft-start circuit output terminal 52 is used to output current-limited electrical energy to the battery module; the controllable mechanical switch 53 is connected in series with the soft-start resistor 54, and then connected in parallel with the semiconductor switch 55; one end of the semiconductor switch 55 is connected to the soft-start circuit input terminal 51, and the other end is connected to the soft-start circuit output terminal 52. See Figure 12 , Figure 12 This is a schematic diagram of another soft-start circuit provided in one embodiment of this specification. The soft-start circuit includes a soft-start circuit input terminal 51, a soft-start circuit output terminal 52, a soft-start resistor 54, a semiconductor switch 55, and a diode 56; The soft-start circuit input terminal 51 is used to receive electrical energy from the inverter DC bus, and the soft-start circuit output terminal 52 is used to output current-limited electrical energy to the battery module; the soft-start resistor 54 is connected in series with the semiconductor switch 55, and the diode 56 is connected in parallel with the series circuit of the soft-start resistor 54 and the semiconductor switch 55.

[0181] The soft-start circuit 32 and the inverter circuit 13 are connected in the circuit in various ways, see [reference needed]. Figure 13 , Figure 13 This is a schematic diagram of a transformer circuit installed on a busbar, provided as an embodiment of this specification.

[0182] Figure 13 In the inverter DC bus 15, the first battery interface 17 and the second battery interface 18 are respectively connected, and the first battery interface 17 and the inverter DC bus 15 are connected in series with a transformer circuit 22. The transformer circuit 22 is located on the electrical connection between the inverter DC bus 15 and the first battery interface 17 and the second battery interface, and is used to adjust the voltage matching relationship between the stacked battery module 2, the split battery module 3 and the inverter DC bus 15.

[0183] See Figure 14 , Figure 14 This is a schematic diagram of another transformer circuit installed on the bus, provided as an embodiment of this specification.

[0184] Figure 14 In the inverter, the DC bus 15 is connected to the first battery interface 17 and the second battery interface 18 respectively. A transformer circuit 22 and a soft start circuit 32 are provided on the electrical connection between the inverter DC bus 15 and the first battery interface 17 and the second battery interface 18 to limit the inrush current when the split battery module is connected.

[0185] This connection method indicates that the first DC circuit and the second DC circuit can share the same transformer circuit 22 and soft-start circuit 32 for voltage conversion.

[0186] See Figure 15 , Figure 15 This specification provides a schematic diagram of another transformer circuit installed on the busbar, as one embodiment of the present specification.

[0187] Figure 15 In the inverter, the DC bus 15 is connected to the first battery interface 17 and the second battery interface 18 respectively, and a transformer circuit 22 is provided on the electrical connection between the inverter DC bus 15 and the first battery interface 17 and the second battery interface 18. A soft-start circuit 32 is also connected in series between the second battery interface 18 and the transformer circuit 22. The soft-start circuit 32 is located between the second battery interface 18 and the transformer circuit 22 and is used to limit the inrush current when the split battery module is connected.

[0188] See Figure 16 , Figure 16 This is a schematic diagram of another transformer circuit installed on the bus, provided as an embodiment of this specification.

[0189] Figure 16 In the inverter, the DC bus 15 is connected to the first battery interface 17 and the second battery interface 18 respectively, and a transformer circuit 22 is provided on the electrical connection between the inverter DC bus 15 and the first battery interface 17 and the second battery interface 18. A first soft-start circuit 32 is connected in series between the first battery interface 17 and the transformer circuit 22, and a second soft-start circuit 32 is connected in series between the second battery interface 18 and the transformer circuit 22. The two soft-start circuits 32 are used to independently limit the inrush current when the stacked battery module and the separate battery module are connected.

[0190] This connection method means that the first DC circuit and the second DC circuit share the same transformer circuit 22 for voltage conversion. At the same time, the two battery circuits are each independently equipped with a soft-start circuit 32 for pre-charging current limiting of their respective circuits. The two soft-start circuits 32 can work simultaneously or independently without interfering with each other.

[0191] See Figure 17 , Figure 17 This is a schematic diagram of a transformer circuit disposed on a split battery module, provided as an embodiment of this specification.

[0192] Figure 17 In the inverter, the DC bus 15 is connected to the first battery interface 17 and the second battery interface 18. A soft-start circuit 32 and a transformer circuit 22 are connected in series between the second battery interface 18 and the inverter DC bus 15. The soft-start circuit 32 and the transformer circuit 22 can be connected in series in the same branch of the second DC circuit. The first battery interface 17 is directly connected to the inverter DC bus 15, indicating that the first DC circuit does not need to be equipped with a transformer circuit and a soft-start circuit, and the voltage level of the stacked battery module itself is directly matched with the bus voltage.

[0193] This connection method indicates that the second DC circuit is configured with a separate transformer circuit 22 and a soft-start circuit 32 to support voltage matching and pre-charge current limiting of the separately connected battery module and the bus, while the first DC circuit adopts a direct connection method.

[0194] See Figure 18 , Figure 18 This is a schematic diagram of another transformer circuit provided on a split battery module, as an embodiment of this specification.

[0195] Figure 18 In the inverter DC bus 15, a first battery interface 17 and a second battery interface 18 are connected to each other. A soft start circuit 32 and a transformer circuit 22 are connected in series between the second battery interface 18 and the inverter DC bus 15. Another transformer circuit 22 is connected in series between the first battery interface 17 and the inverter DC bus 15. In the first DC circuit, another transformer circuit 22 is connected in series between the first battery interface 17 and the inverter DC bus 15 to adjust the voltage matching relationship between the stacked battery module and the inverter DC bus 15. The first DC circuit may not have a soft start circuit, or a soft start circuit may be configured as needed.

[0196] This connection method indicates that the first DC circuit and the second DC circuit are each independently configured with their own transformer circuit 22. The second DC circuit is additionally equipped with a soft-start circuit 32 for pre-charging current limiting, while the first DC circuit may or may not be equipped with a soft-start circuit depending on actual needs. The transformer circuits 22 of the two battery circuits can have the same or different voltage transformation parameters to accommodate battery modules of different specifications being connected to the same inverter DC bus simultaneously.

[0197] See Figure 5 , Figure 5 This specification provides a schematic diagram of the structure of an optical energy storage system including a soft-start circuit, as an embodiment of the present invention. Specifically: The photovoltaic-storage system 6 includes a photovoltaic-storage inverter 1, a stacked battery module 2, and a separate battery module 3. The photovoltaic-storage inverter 1 includes a photovoltaic module 1, a photovoltaic transformer circuit 12, an inverter circuit 13, an AC interface 14, a DC bus 15, an inverter main controller 16, a first battery interface 17, a second battery interface 18, a photovoltaic interface 19, a communication bus 41, a first communication interface 42, a second communication interface 43, and a soft-start circuit 32. The stacked battery module 2 includes a first sub-controller 21, a transformer circuit 22, a battery 23, and a soft-start circuit 32. The separate battery module 3 includes a second sub-controller 31, a transformer circuit 22, a battery 23, and a soft-start circuit 32. The photovoltaic interface 19 is used to connect the photovoltaic module. The photovoltaic transformer circuit 12 is connected between the photovoltaic interface 19 and the inverter DC bus 15. The inverter circuit 13 is connected between the inverter DC bus 15 and the AC interface 14. The AC interface 14 is used to connect to the voltage source network or AC load. The first battery interface 17 is used to connect to the stacked battery module 2 in a stacked plug-in connection to form a first DC circuit. The second battery interface 18 is used to connect to the split battery module 3 separately to form a second DC circuit. The first battery interface 17 and the second battery interface 18 are respectively connected in parallel to the inverter DC bus 15. Photovoltaic-storage inverters also include photovoltaic transformer circuits; The photovoltaic transformer circuit is connected in series in the electrical connection between the photovoltaic module and the photovoltaic-energy storage inverter.

[0198] The photovoltaic transformer circuit can be connected in series between the photovoltaic module and the photovoltaic-energy storage inverter in the following ways: Close to the photovoltaic module side: The photovoltaic transformer circuit is directly connected to the output terminal of the photovoltaic module. The photovoltaic module is first connected to the transformer circuit, and the voltage is boosted before being transmitted to the photovoltaic-storage inverter through a cable. Close to the photovoltaic-storage inverter side: The photovoltaic transformer circuit is located inside the photovoltaic-storage inverter, between the photovoltaic interface and the inverter DC bus. The low-voltage DC power of the photovoltaic module is transmitted to the inverter via a long-distance cable and is boosted inside the inverter. Independent external method: The photovoltaic transformer circuit is an independent module, connected in series in the cable between the photovoltaic module and the photovoltaic-energy storage inverter. The photovoltaic module is connected to the external transformer circuit and then connected to the photovoltaic-energy storage inverter. Integrated into the photovoltaic junction box: The photovoltaic transformer circuit is integrated into the junction box of the photovoltaic module. Each photovoltaic module has its own boost function and outputs high-voltage DC power.

[0199] In the stacked battery module 2, the transformer circuit 22 and the soft-start circuit 32 are connected in series between the battery 23 and the first battery interface 17. The soft-start circuit 32 is used to limit the inrush current when the stacked battery module 2 is connected, and the transformer circuit 22 is used to adjust the voltage matching relationship between the stacked battery module 2 and the inverter DC bus 15. The first sub-controller 21 is used to monitor the operating status of the stacked battery module 2 and receive control commands sent by the main controller 16. In the split battery module 3, the transformer circuit 22 and the soft start circuit 32 are connected in series between the battery 23 and the second battery interface 18 to limit the inrush current when the split battery module 3 is connected; the second sub-controller 31 is used to monitor the operating status of the split battery module 3 and receive control commands sent by the main controller 16. The first communication interface 42 is associated with the first battery interface 17 and is used to communicate with the first sub-controller 21. The second communication interface 43 is associated with the second battery interface 18 and is used to communicate with the second sub-controller 31. The first communication interface 42 and the second communication interface 43 are respectively connected to the main controller 16 through the communication bus 41. The main controller 16 is used to obtain the operating status of the stacked battery module 2 through the first communication interface 42 and the operating status of the split battery module 3 through the second communication interface 43. The main controller 16 is also used to send a first control command to the first sub-controller 21 through the first communication interface 42 and a second control command to the second sub-controller 31 through the second communication interface 43, so as to control the charging and discharging power flowing through the first DC circuit and the second DC circuit.

[0200] The main controller 16 is located in the photovoltaic-storage inverter 1, the first sub-controller 21 is located in the stacked battery module 2, and the second sub-controller 31 is located in the split battery module 3.

[0201] The main controller 16 can be installed in the photovoltaic-storage inverter 1 in the following ways: PCB board integration: the main controller 16 is directly soldered or inserted into the main control circuit board of the photovoltaic-storage inverter 1 in the form of a chip; modular plug-in method: the main controller 16 is made into an independent control module and is inserted into the corresponding socket of the photovoltaic-storage inverter 1 through a board-to-board connector or ribbon cable; embedded installation method: the main controller 16 chip is embedded in the photovoltaic-storage inverter 1 and integrated on the same package or the same substrate; independent control box method: the main controller 16 is set in an independent control box, and the control box is connected to the photovoltaic-storage inverter 1 through a cable or ribbon cable.

[0202] The first sub-controller 21 can be configured in the stacked battery module 2 in the following ways: integrated into the battery management system motherboard: the first sub-controller acts as the main control chip and is soldered onto the battery management system circuit board inside the stacked battery module 2; independent slave board mode: the first sub-controller 21 is configured on an independent slave board, which is connected to the battery management system motherboard inside the stacked battery module 2 via a connector; or embedded inside the battery 23: the chip of the first sub-controller 21 is embedded inside the package of the battery 23 and integrated with the cell or battery protection circuit.

[0203] The method of setting the second sub-controller 31 in the separate battery module 3 can refer to the method of setting the first sub-controller 21 in the stacked battery module 2.

[0204] See Figure 6 , Figure 6 This specification provides a schematic diagram of a photovoltaic energy storage system with a controller mounted on a battery module, as one embodiment of the present invention. Specifically: The photovoltaic-storage system 6 includes a photovoltaic-storage inverter 1, a stacked battery module 2, and a separate battery module 3. The photovoltaic-storage inverter 1 includes a photovoltaic module 11, a photovoltaic transformer circuit 12, an inverter circuit 13, an AC interface 14, an inverter DC bus 15, a main controller 16, a first battery interface 17, a second battery interface 18, a photovoltaic interface 19, a communication bus 41, a first communication interface 42, and a second communication interface 43. The stacked battery module 2 includes multiple first sub-controllers 21, a transformer circuit 22, a battery 23, and a soft-start circuit 32. The separate battery module 3 includes multiple second sub-controllers 31, a battery 23, and a soft-start circuit 32. The photovoltaic module 11 is electrically connected to the photovoltaic-storage inverter 1 via the photovoltaic interface 19. The photovoltaic transformer circuit 12 is connected between the photovoltaic interface 19 and the inverter DC bus 15. The inverter circuit 13 is connected between the inverter DC bus 15 and the AC interface 14. The AC interface 14 is used to connect to a voltage source network or an AC load. The first battery interface 17 is used to connect to the stacked battery module 2 in a stacked plug-in manner to form a first DC circuit. The second battery interface 18 is used to connect to the split battery module 3 separately to form a second DC circuit. The first battery interface 17 and the second battery interface 18 are respectively connected in parallel to the inverter DC bus 15. In the stacked battery module 2, the transformer circuit 22 and the soft-start circuit 32 are connected in series between the battery 23 and the first battery interface 17. The soft-start circuit 32 is used to limit the inrush current when the stacked battery module 2 is connected, and the transformer circuit 22 is used to adjust the voltage matching relationship between the stacked battery module 2 and the inverter DC bus 15. The first sub-controller 21 is set in the stacked battery module 2 and is used to monitor the operating status of the stacked battery module 2 and receive control commands sent by the main controller 16. In the split battery module 3, the soft start circuit 32 is connected in series between the battery 23 and the second battery interface 18 to limit the inrush current when the split battery module 3 is connected; the second sub-controller 31 is located in the split battery module 3 to monitor the operating status of the split battery module 3 and receive control commands sent by the main controller 16. The main controller 16 is located in the photovoltaic-storage inverter 1. The first communication interface 42 is associated with the first battery interface 17 and is used to communicate with the first sub-controller 21. The second communication interface 43 is associated with the second battery interface 18 and is used to communicate with the second sub-controller 31. The first communication interface 42 and the second communication interface 43 are respectively connected to the main controller 16 through the communication bus 41. The main controller 16 is used to obtain the operating status of the stacked battery module 2 through the first communication interface 42 and the operating status of the split battery module 3 through the second communication interface 43. The main controller 16 is also used to send a first control command to the first sub-controller 21 through the first communication interface 42 and a second control command to the second sub-controller 31 through the second communication interface 43, so as to control the charging and discharging power flowing through the first DC circuit and the second DC circuit.

[0205] Each of the first sub-controllers 21 is respectively disposed in the battery pack of the stacked battery module 2. Each battery pack is also provided with a transformer circuit 22, a battery 23 and a soft start circuit 32 electrically connected to the first sub-controller 21. Each of the second sub-controllers 31 is respectively disposed in the battery pack of the split battery module 3. Each battery pack is also provided with a battery 23 and a soft start circuit 32 electrically connected to the second sub-controller 31.

[0206] This connection method indicates that the first sub-controller 21 is located inside the stacked battery module 2, the second sub-controller 31 is located inside the split battery module 3, and the main controller 16 is located inside the photovoltaic-storage inverter 1, forming a control architecture that combines distributed monitoring and centralized decision-making.

[0207] The above is a schematic scheme of a photovoltaic-storage inverter according to this embodiment. It should be noted that the technical solution of this photovoltaic-storage inverter and the technical solution of the control method of the photovoltaic-storage inverter described above belong to the same concept. For details not described in detail in the technical solution of the photovoltaic-storage inverter, please refer to the description of the technical solution of the control method of the photovoltaic-storage inverter described above.

[0208] The above is a schematic diagram of a computing device according to this embodiment. It should be noted that the technical solution of this computing device and the technical solution of the control method for the photovoltaic-storage inverter described above belong to the same concept. For details not described in detail in the technical solution of the computing device, please refer to the description of the technical solution of the control method for the photovoltaic-storage inverter described above.

[0209] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0210] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments in this specification are not limited to the described order of actions, because according to the embodiments in this specification, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the embodiments in this specification.

[0211] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0212] The preferred embodiments disclosed above are merely illustrative of this specification. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the embodiments described herein. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the embodiments, thereby enabling those skilled in the art to better understand and utilize this specification. This specification is limited only by the claims and their full scope and equivalents.

Claims

1. A control method for a photovoltaic-storage inverter, characterized in that, The photovoltaic-storage inverter includes an AC interface, a first battery interface, a second battery interface, a first DC circuit, and a second DC circuit. The AC interface is used to electrically connect to a voltage source network. The first DC circuit is electrically connected to the first battery interface, which is used to electrically connect to a stacked battery module. The second DC circuit is electrically connected to the second battery interface, which is used to electrically connect to a separate battery module. The method includes: In response to the second battery interface being connected to the split battery module, the operating status of the photovoltaic-storage inverter is monitored; The second DC circuit is controlled according to the operating status of the photovoltaic-storage inverter.

2. The method according to claim 1, characterized in that, The step of controlling the second DC circuit according to the operating state of the photovoltaic-storage inverter includes: The charging and discharging state of the second DC circuit is controlled according to the operating state of the photovoltaic-storage inverter. The operating state includes charging state, discharging state, or fault state.

3. The method according to claim 1, characterized in that, The step of monitoring the operating status of the photovoltaic-storage inverter in response to the second battery interface connecting to the split battery module includes: In response to the first battery interface being connected to the stacked battery module and the second battery interface being connected to the split battery module, the operating state of the photovoltaic-storage inverter is determined to be a multi-battery operating state. During the multi-battery operation, the operating status of the photovoltaic-storage inverter is monitored; The step of controlling the second DC circuit according to the operating state of the photovoltaic-storage inverter further includes: The first DC circuit and the second DC circuit are controlled according to the operating status of the photovoltaic-storage inverter.

4. The method according to claim 3, characterized in that, The monitoring of the operating status of the photovoltaic-storage inverter under the multi-battery operating state includes: In the multi-battery operation state, the operation status of the stacked battery module connected to the photovoltaic-storage inverter and the operation status of the split battery module connected to the photovoltaic-storage inverter are monitored respectively. The operating status of the photovoltaic-storage inverter is determined based on the operating status of the stacked battery module and the operating status of the separate battery module.

5. The method according to claim 3, characterized in that, The operating status of the photovoltaic-storage inverter also includes stacked battery module failure and separate battery module failure; The step of controlling the first DC circuit and the second DC circuit according to the operating state of the photovoltaic-storage inverter includes: In the event of a stacked battery module failure during operation, the first DC circuit is disconnected while the second DC circuit is maintained. In the event of a fault in the separate battery module during operation, the second DC circuit is disconnected while the first DC circuit is maintained.

6. The method according to claim 1, characterized in that, The photovoltaic-storage inverter also includes a photovoltaic interface and a third DC circuit. The third DC circuit is electrically connected to the photovoltaic interface, which is used to connect to the photovoltaic module externally. The operating status of the photovoltaic-storage inverter also includes a photovoltaic charging status. The monitoring of the operating status of the photovoltaic-storage inverter includes: Monitor the photovoltaic input voltage of the photovoltaic interface; When the photovoltaic input voltage is greater than the preset power supply voltage, the operating state is determined to be the photovoltaic charging state; The method further includes: When the operating state is photovoltaic charging state, the photovoltaic interface is controlled to supply power to the stacked battery module and the separate battery module respectively.

7. The method according to claim 6, characterized in that, The photovoltaic-storage inverter also includes a photovoltaic transformer circuit, which is connected in series with the third DC circuit. The control of the photovoltaic interface to supply power to the stacked battery module and the separate battery module respectively includes: The photovoltaic input current input through the photovoltaic interface is boosted to the bus voltage of the photovoltaic-storage inverter; The bus voltage supplies power to the stacked battery module and the separate battery module respectively.

8. The method according to claim 7, characterized in that, The first DC circuit is provided with a first transformer circuit, and the second DC circuit is provided with a second transformer circuit; Before supplying power to the stacked battery module and the separate battery module respectively with the bus voltage, the method further includes: Monitor the voltage of the individual battery modules of the individual battery modules and / or the voltage of the stacked battery modules of the stacked battery modules respectively; The provision of power to the stacked battery module and the separate battery module using the bus voltage includes at least one of the following: The second voltage difference between the bus voltage and the separate battery module voltage is controlled by the second transformer circuit to supply power to the separate battery module. The first voltage difference between the bus voltage and the stacked battery module voltage is controlled by the first transformer circuit to supply power to the stacked battery module.

9. The method according to claim 1, characterized in that, The first DC circuit is further provided with a first soft-start circuit, and the second DC circuit is further provided with a second soft-start circuit; The step of controlling the second DC circuit according to the operating state of the photovoltaic-storage inverter includes: When the operating state is charging state, the second DC circuit is controlled to supply power to the split battery module via the second soft-start circuit; The method further includes: When the operating state is charging state, the first DC circuit is controlled to supply power to the stacked battery module via the first soft-start circuit.

10. The method according to claim 9, characterized in that, The second soft-start circuit includes a soft-start input terminal, a soft-start output terminal, a soft-start resistor, a soft-start switch connected in series with the soft-start resistor, and a bypass switch connected in parallel in the second soft-start circuit; The supply of power to the split battery module via the second soft-start circuit includes: Close the soft-start switch and open the bypass switch. Based on the soft-start resistor, limit the charging current input to the soft-start input terminal to obtain the limiting current at the soft-start output terminal. Power is supplied to the separate battery module according to the current limiting condition; When the charging current drops to a preset current threshold, the bypass switch is closed and the soft-start switch is opened to supply power to the separate battery module according to the charging current.

11. The method according to claim 1, characterized in that, The communication interface is also used to connect a load; The method further includes at least one of the following: In response to the AC interface being connected to the load, the stacked battery module supplies power to the load through the AC interface; In response to the AC interface being connected to the load, the separate battery module supplies power to the load through the AC interface; In response to the AC interface being connected to the load, the stacked battery module and the separate battery module supply power to the load through the AC interface.

12. The method according to any one of claims 1-11, characterized in that, The photovoltaic-storage inverter also includes a main controller, which is used to control a first sub-controller configured in the stacked battery module and a second sub-controller configured in the split battery module. The monitoring of the operating status of the photovoltaic-storage inverter includes: The main controller monitors the operating status of the stacked battery module based on the first sub-controller and monitors the operating status of the split battery module based on the second sub-controller. The step of controlling the second DC circuit according to the operating state of the photovoltaic-storage inverter includes: The main controller sends a second control command to the second sub-controller according to the operating status of the photovoltaic-storage inverter to control the second DC circuit; The method further includes: The main controller sends a first control command to the first sub-controller based on the operating status of the photovoltaic-storage inverter to control the first DC circuit.

13. The method according to claim 12, characterized in that, The photovoltaic-storage inverter also includes a communication bus that is connected to the main controller. The communication bus is connected to a first communication interface for communicating with the stacked battery module and a second communication interface for communicating with the separate battery module. The main controller sends a second control command to the second sub-controller based on the operating status of the photovoltaic-storage inverter to control the second DC circuit, including: The main controller, based on the operating status of the photovoltaic-storage inverter, sends a second control command to the second sub-controller via the communication bus and the second communication interface to control the second DC circuit; The main controller sends a first control command to the first sub-controller based on the operating status of the photovoltaic-storage inverter to control the first DC circuit, including: The main controller, based on the operating status of the photovoltaic-storage inverter, sends a first control command to the first sub-controller via the first communication interface through the communication bus to control the first DC circuit.

14. A photovoltaic-storage inverter, characterized in that, The photovoltaic-storage inverter includes an AC interface, a first battery interface, a second battery interface, a first DC circuit, and a second DC circuit. The AC interface is used to electrically connect to a voltage source network. The first DC circuit is electrically connected to the first battery interface, which is used to electrically connect to a stacked battery module. The second DC circuit is electrically connected to the second battery interface, which is used to electrically connect to a separate battery module. The voltage source network is electrically connected to the photovoltaic-storage inverter via an AC interface. The stacked battery module is electrically connected to the photovoltaic-storage inverter via the first battery interface to form a first DC circuit. The split battery module is electrically connected to the photovoltaic-storage inverter via the second battery interface to form a second DC circuit.

15. The photovoltaic-storage inverter according to claim 14, characterized in that, It also includes a photovoltaic interface and a third DC circuit, wherein the third DC circuit is electrically connected to the photovoltaic interface, and the photovoltaic interface is used for external electrical connection to the photovoltaic module; The photovoltaic module is electrically connected to the photovoltaic-storage inverter through the photovoltaic interface to form a photovoltaic circuit.

16. The photovoltaic-storage inverter according to claim 15, characterized in that, The photovoltaic-storage inverter also includes a photovoltaic transformer circuit, which is connected in series with the third DC circuit.

17. The photovoltaic-storage inverter according to claim 14, characterized in that, It also includes a first soft-start circuit and a second soft-start circuit, wherein the first soft-start circuit is connected in series with the first DC circuit and the second soft-start circuit is connected in series with the second DC circuit.

18. The photovoltaic-storage inverter according to claim 14, characterized in that, It also includes a main controller, which is used to control a first sub-controller configured in the stacked battery module and a second sub-controller configured in the split battery module; The main controller is located in the photovoltaic-storage inverter, the first sub-controller is located in the stacked battery module, and the second sub-controller is located in the separate battery module.

19. The photovoltaic-storage inverter according to claim 14, characterized in that, It also includes a communication bus, which is connected to a first communication interface for communicating with the stacked battery module and a second communication interface for communicating with the separate battery module. The communication bus is located in the photovoltaic-storage inverter and is connected to the first communication interface and the second communication interface respectively.

20. A photovoltaic energy storage system, characterized in that, include: A photovoltaic-storage inverter, and photovoltaic modules, voltage source networks, stacked battery modules, and split battery modules connected to the photovoltaic-storage inverter; The stacked battery module is electrically connected to the photovoltaic-storage inverter to form a first DC circuit; The separate battery module is electrically connected to the photovoltaic-storage inverter to form a second DC circuit.

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