Photovoltaic energy storage and bidirectional inversion conversion system, method, equipment and medium

Abstract

A photovoltaic energy storage and bidirectional inversion conversion system, method, device and medium relate to the photovoltaic inverter field, and the system comprises a photovoltaic inverter, a photovoltaic input DC-DC module, a DC-DC output module, a battery bidirectional DC-DC module, a bidirectional DC-AC module and a DC bus module; the first end of the photovoltaic input DC-DC module is connected with the photovoltaic panel, and the second end of the photovoltaic input DC-DC module is connected with the DC bus module; the first end of the DC-DC output module is connected with the DC bus module, and the second end of the DC-DC output module is connected with the photovoltaic inverter; the first end of the battery bidirectional DC-DC module is connected with the DC bus module, and the second end is connected with the battery; the first end of the bidirectional DC-AC module is connected with the DC bus module, the second end is connected with the load, and the third end is connected with the photovoltaic inverter. According to the application, a direct-current side transformation path is adopted, and a mode relying on alternating-current side large-scale line transformation is replaced through collaborative design of all modules.

Description

Technical Field

[0001] This application relates to the field of photovoltaic inverters, and in particular to a photovoltaic energy storage and bidirectional inverter conversion system, method, equipment and medium. Background Technology

[0002] The development of distributed renewable energy has driven the growth of residential photovoltaic (PV) systems. Existing residential PV systems are mostly pure PV systems, relying solely on solar power. Their output is significantly affected by weather and diurnal variations, and they are essentially unable to generate electricity on cloudy or rainy days or under other conditions. When power generation exceeds demand, the excess energy is often not fully utilized due to grid limitations; and when there is insufficient sunlight or at night, the system cannot supply power, resulting in low self-consumption rates and consequently reducing overall economic efficiency.

[0003] The peak period for photovoltaic power generation is generally around noon, but this is off-peak electricity consumption time, which can lead to energy waste in residential pure photovoltaic systems. Furthermore, without energy storage devices as a buffer, the system struggles to address the timing mismatch between load and power generation, easily causing instantaneous energy waste or power shortages, especially noticeable on the user side where peak and off-peak electricity consumption patterns are pronounced.

[0004] Existing residential pure photovoltaic (PV) system retrofits primarily rely on the AC side, requiring large-scale modifications to the AC power supply circuits. This necessitates power outages during construction, disrupting normal operation. Furthermore, compliance with International Electrotechnical Commission (IEC) standards necessitates upgrading safety protection devices, leading to high retrofit costs and reduced system availability. Moreover, current solutions cannot accommodate additional solar panels, limiting flexibility in increasing PV input or oversizing, and hindering efforts to boost system power. Summary of the Invention

[0005] The purpose of this application is to provide a photovoltaic energy storage and bidirectional inverter conversion system, method, equipment and medium to overcome the defects of the prior art.

[0006] In a first aspect, this application provides a photovoltaic energy storage and bidirectional inverter conversion system, comprising: Photovoltaic inverters, photovoltaic input DC-DC modules, DC-DC output modules, battery bidirectional DC-DC modules, bidirectional DC-AC modules, and DC bus modules; The first end of the photovoltaic input DC-DC module is connected to the photovoltaic panel, and the second end is connected to the DC bus module. The photovoltaic input DC-DC module includes an MPPT DC input unit. The first end of the DC-DC output module is connected to the DC bus module, and the second end is connected to the photovoltaic inverter; The first end of the battery bidirectional DC-DC module is connected to the DC bus module, and the second end is connected to the battery. The first end of the bidirectional DC-AC module is connected to the DC bus module, the second end is connected to the load, and the third end is connected to the photovoltaic inverter.

[0007] By adopting the above technical solutions, an integrated modular energy management architecture is constructed. Core components are connected in series through photovoltaic input DC-DC modules, DC bus modules, and other modules, forming an energy harvesting, conversion, storage, and distribution chain, breaking the limitations of isolated operation of components in pure photovoltaic systems. This provides the hardware foundation for maximizing photovoltaic power utilization, intelligent control of battery charging and discharging, flexible load power supply, and grid-connected / off-grid switching.

[0008] In one specific implementation scheme, the photovoltaic input DC-DC module, DC-DC output module, battery bidirectional DC-DC module, DC bus module and bidirectional DC-AC module all include multiple parallel-configured sub-modules, and the overall inverter power of the system can be adjusted by increasing or decreasing the number of parallel sub-modules. The sub-modules establish communication connections through a CAN bus. Based on the status information of each sub-module, a master module is determined through distributed collaborative control logic and a preset election mechanism. The master module is used to uniformly control each sub-module.

[0009] By adopting the above technical solution and employing a modular parallel design, the overall inverter power can be adjusted by adding or removing the number of parallel sub-modules. This solves the problem of fixed power in traditional photovoltaic systems, which cannot be flexibly upgraded according to user electricity demand or photovoltaic installed capacity. The modular design greatly simplifies the system installation and modification process, eliminating the need for large-scale reconstruction of the original photovoltaic inverters or power supply lines, thus enhancing the overall practicality and economy of the system.

[0010] In one specific implementation scheme, the distributed collaborative control logic includes: The main module sends a synchronization control frame to each of the sub-modules via the CAN bus. The synchronization control frame is used to calibrate the working timing of each of the sub-modules. Each of the sub-modules sends a status feedback frame to the main module via the CAN bus, and the main module adjusts the power allocation command based on the status feedback frame.

[0011] By adopting the above technical solutions, an efficient and stable inter-module communication and collaborative control system is constructed. Synchronization control frames are uniformly sent by the main module to ensure the consistency of the working timing of each sub-module and avoid power fluctuations or energy conflicts caused by timing errors. Status feedback frames are uploaded by each sub-module in real time, and the main module dynamically corrects the power allocation instructions based on the feedback data, realizing real-time monitoring and rapid response of the system's operating status.

[0012] In a specific feasible implementation, the system generates the power allocation instruction based on the photovoltaic input power uploaded by the photovoltaic input DC-DC submodule, the battery state of charge (SOC) uploaded by the battery bidirectional DC-DC submodule, and the total load power uploaded by the bidirectional DC-AC submodule, and adjusts the output power of each of the photovoltaic input DC-DC submodule, battery bidirectional DC-DC submodule, and bidirectional DC-AC submodule based on the power allocation instruction; When the photovoltaic input power is greater than or equal to the first threshold, the excess photovoltaic power is distributed to the battery for energy storage through the battery bidirectional DC-DC submodule. When the photovoltaic input power is less than the first threshold, the energy of the battery is distributed to the load through the bidirectional DC-DC submodule and the bidirectional DC-AC submodule, and the energy distribution ratio is adjusted based on the load.

[0013] By adopting the above technical solution, power allocation instructions are generated for targeted energy dispatch. When the photovoltaic input power is sufficient, excess energy is preferentially stored in the battery, improving the self-consumption rate of photovoltaic energy. When the photovoltaic input power is insufficient, coordinated discharge is carried out, and the energy allocation ratio is dynamically adjusted to ensure continuous power supply to important loads, optimize energy flow efficiency, improve the system's adaptability to complex power consumption scenarios, and further enhance the economy and reliability of the photovoltaic energy storage system.

[0014] In one specific implementation scheme, when the photovoltaic input DC-DC submodule is over-supplied, each of the photovoltaic input DC-DC submodules uploads the maximum power point to the DC-DC output submodule via the CAN bus; Each of the DC-DC output submodules adjusts the MPPT simulation curve based on its maximum power point and overfitting ratio.

[0015] By adopting the above technical solution, a collaborative strategy of uploading the maximum power point (MPPT) and dynamically adjusting the simulation curve is employed. When the photovoltaic submodule is oversupplied, i.e., the total power exceeds the inverter's rated input, the maximum power point parameter is uploaded to ensure that an MPPT simulation curve adapted to the inverter can be accurately generated. When the oversupplied ratio changes, the simulation curve is dynamically adjusted according to the oversupplied ratio and the MPPT period to ensure that the photovoltaic energy is fully utilized under oversupplied conditions.

[0016] In one specific implementation, the second end of each battery bidirectional DC-DC submodule is connected to multiple parallel battery packs, and each battery bidirectional DC-DC submodule monitors the ripple characteristics of the capacitor voltage of the DC bus submodule. Based on the ripple characteristics, each of the battery bidirectional DC-DC submodules adjusts the charging and discharging current.

[0017] By adopting the above technical solution, a charging and discharging adjustment strategy is implemented based on ripple characteristics. Energy surge risks are identified by monitoring ripple characteristics, and the charging and discharging current is adjusted synchronously at a rate correlated with the ripple characteristics. Ripple compensation is achieved by utilizing the energy storage characteristics of the DC bus capacitor, significantly reducing voltage fluctuation amplitude.

[0018] In a specific feasible implementation, when the system triggers off-grid mode, each bidirectional DC-AC submodule establishes direct communication with the photovoltaic input DC-DC submodule via the CAN bus, and supplies the photovoltaic input power to the load via the DC bus. Based on the difference between the photovoltaic input power and the load demand, each of the battery bidirectional DC-DC sub-modules generates supplementary power; Based on the rate of change of the photovoltaic input power, each of the battery bidirectional DC-DC submodules adjusts the supplementary power.

[0019] By adopting the above technical solution, a coordinated strategy for direct photovoltaic power supply and battery power supplementation is designed. When off-grid mode is triggered, photovoltaic power is supplied to the load via the DC bus; supplementary power is dynamically allocated according to the real-time power difference to ensure the continuity of power supply to the load; when the photovoltaic power change rate exceeds the second threshold, the incremental growth rate of supplementary power is adjusted based on the change rate within a preset response window.

[0020] Secondly, this application also provides a photovoltaic energy storage and bidirectional inverter conversion method, including: The photovoltaic input DC-DC module monitors the output voltage and current of the photovoltaic panel, dynamically adjusts the input parameters based on a preset algorithm to track the maximum power point, converts the electrical energy generated by the photovoltaic panel into a voltage that is compatible with the DC bus module, and transmits it to the DC bus module. The DC bus module maintains a stable DC voltage through capacitor elements and suppresses voltage and current fluctuations and noise through a buffer filter unit, thus performing unified transfer of the received electrical energy. The DC-DC output module obtains electrical energy from the DC bus module, simulates the MPPT curve of the photovoltaic inverter through the MPPT simulation curve unit, adjusts the curve power and combines the detection results of the smart meter to transmit electrical energy to the photovoltaic inverter, realizing self-generation and self-consumption on the grid side; The battery bidirectional DC-DC module monitors the battery's status parameters through an integrated management unit. When charging is required, the electrical energy from the DC bus module is converted into a voltage and current suitable for the battery via a buck-boost unit to charge the battery. When discharging is required, the electrical energy stored in the battery is converted and transmitted to the DC bus module via a buck-boost unit. The bidirectional DC-AC module obtains power from the DC bus module, supplies power to the load through the load control unit, and controls the load to switch between grid-connected mode and off-grid mode according to the mains power status; when the mains power fails, the load backup power unit switches to photovoltaic power or battery energy storage power supply path to continuously supply power to the load.

[0021] By adopting the above technical solutions, the entire process of energy flow in the system is optimized. From photovoltaic power acquisition and stable DC bus transfer to power distribution, a logically closed-loop energy management mechanism is formed. Through the coordinated operation of each step, this method ensures a dynamic balance between photovoltaic power, battery energy storage, and load demand, significantly improving energy utilization, system stability, and the user's electricity experience.

[0022] Thirdly, this application also provides an electronic device, including a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory to enable the electronic device to perform a photovoltaic energy storage and bidirectional inverter conversion method.

[0023] Fourthly, this application also provides a computer-readable storage medium storing multiple instructions adapted for loading and execution by a processor of a photovoltaic energy storage and bidirectional inverter conversion method.

[0024] In summary, this application includes at least one of the following beneficial effects: This application adopts a DC-side retrofit approach, replacing the traditional model that relies on large-scale AC-side line modifications through the collaborative design of core modules such as the photovoltaic input DC-DC module, DC bus module, and battery bidirectional DC-DC module. Simultaneously, the modular DC-side architecture provides the hardware foundation for subsequent expansion of energy storage capacity and the addition of photovoltaic panels.

[0025] Each core module in this application allows for adjustment of overall power by adding or removing sub-modules, meeting users' dynamic needs from low to high power. Simultaneously, a CAN bus-based synchronous control frame and status feedback frame mechanism enables timing calibration, power allocation coordination, and mode switching linkage among multiple sub-modules.

[0026] This application constructs a closed-loop energy system integrating photovoltaic power generation, energy storage buffering, and load power supply. Batteries act as a dynamic buffer medium, suppressing timing mismatches between photovoltaic output and load demand; they support off-grid mode switching, ensuring continuous power supply to critical loads through a coordinated strategy of direct photovoltaic power supply and battery replenishment. The system rapidly adjusts battery charging and discharging rates through mechanisms such as ripple monitoring and power change rate response, further enhancing power supply stability. Attached Figure Description

[0027] Figure 1This is a schematic diagram of a photovoltaic energy storage and bidirectional inverter conversion system provided in an embodiment of this application; Figure 2 This is another structural schematic diagram of a photovoltaic energy storage and bidirectional inverter conversion system provided in the embodiments of this application; Figure 3 This is a schematic flowchart of a photovoltaic energy storage and bidirectional inverter conversion method provided in an embodiment of this application. Detailed Implementation

[0028] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification of this application, the singular expressions “a,” “an,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to any or all possible combinations including one or more of the listed items.

[0029] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0031] refer to Figure 1 , Figure 1 This illustration shows a schematic diagram of a photovoltaic energy storage and bidirectional inverter conversion system according to an embodiment of this application. The system includes: a photovoltaic inverter, a photovoltaic input DC-DC module, a DC-DC output module, a battery bidirectional DC-DC module, a bidirectional DC-AC module, and a DC bus module; the first end of the photovoltaic input DC-DC module is connected to the photovoltaic panel, and the second end is connected to the DC bus module; the photovoltaic input DC-DC module includes an MPPT DC input unit; the first end of the DC-DC output module is connected to the DC bus module, and the second end is connected to the photovoltaic inverter; the first end of the battery bidirectional DC-DC module is connected to the DC bus module, and the second end is connected to the battery; the first end of the bidirectional DC-AC module is connected to the DC bus module, the second end is connected to the load, and the third end is connected to the photovoltaic inverter. In this embodiment, the Maximum Power Point Tracking (MPPT) DC input unit is the core functional module of the photovoltaic input DC-DC module. By monitoring the output voltage and current of the photovoltaic panel in real time, it dynamically adjusts the input parameters based on a preset algorithm to accurately track the maximum power point (MPP) of the photovoltaic panel. This ensures that the photovoltaic panel always operates at the maximum output power when environmental conditions such as light intensity and temperature change, thereby maximizing the extraction of photovoltaic power.

[0032] Specifically, when there is sufficient sunlight (such as at noon during the day), the photovoltaic power generation exceeds the load demand. The photovoltaic panel generates DC power, which is transmitted to the photovoltaic input DC-DC module. The photovoltaic input DC-DC module monitors the voltage and current of the photovoltaic panel in real time through the MPPT DC input unit, and uses the perturbation observation method or incremental conductance method to track the maximum power point, efficiently converting the power and transmitting it to the DC bus module. The DC bus module maintains a stable voltage through capacitor elements and distributes the power to the DC-DC output module. The DC-DC output module simulates and adapts the MPPT curve of the photovoltaic inverter, adjusts the power, and transmits it to the photovoltaic inverter, converting it into AC power for the load. The integrated management unit of the bidirectional DC-DC module detects that the battery is not fully charged and controls the buck-boost unit to convert the DC bus voltage to a voltage and current adapted to the battery. If the battery is fully charged, the bidirectional DC-AC module can invert the excess power into AC power, which is then fed into the grid through the photovoltaic inverter and smart meter.

[0033] When sunlight is weak (e.g., on cloudy days), photovoltaic power generation is less than the load demand. The photovoltaic input DC-DC module extracts photovoltaic power through the MPPT function and transmits it to the DC bus module; the DC-DC output module transmits photovoltaic power to the photovoltaic inverter to supply part of the load; the integrated management unit of the battery bidirectional DC-DC module detects the load demand gap, controls the battery to discharge, and the energy stored in the battery is converted by the buck-boost unit and transmitted to the DC bus module to supplement the insufficient photovoltaic power supply; the bidirectional DC-AC module obtains mixed power from photovoltaic and battery power from the DC bus to continuously supply power to the load.

[0034] When there is no sunlight (such as at night), the system relies solely on battery energy storage. The photovoltaic input DC-DC module stops working, and the battery bidirectional DC-DC module starts discharging according to load demand, converting battery power to the DC bus module. The DC-DC output module stops transmitting power to the photovoltaic inverter. The bidirectional DC-AC module obtains battery power from the DC bus and inverts it into AC power for the load. Simultaneously, the load control unit monitors the mains power status. If the mains power is normal, it can switch to grid-connected mode; if the mains power price is high, it maintains off-grid mode to reduce electricity costs. Grid-connected mode means the system remains connected to the public grid, enabling coordinated dispatch of photovoltaic power, battery energy storage, and grid power. Off-grid mode means the system is disconnected from the public grid, relying entirely on photovoltaic power or battery energy storage to power the load.

[0035] When the mains power fails, the system switches to off-grid mode and activates the load backup power unit. During the daytime, when there is photovoltaic power, the electrical energy collected by the photovoltaic input DC-DC module is transmitted to the bidirectional DC-AC module via the DC bus, directly powering critical loads. Excess electrical energy can be used to charge the battery via the battery bidirectional DC-DC module. At night or on cloudy days, when there is no photovoltaic power, the battery bidirectional DC-DC module releases its stored energy, which is transmitted to the bidirectional DC-AC module via the DC bus, ensuring continuous power supply to critical loads.

[0036] In some embodiments, the MPPT DC input unit may include an MPPT tracking unit. The MPPT tracking unit is used to monitor the output voltage and current of the photovoltaic panel in real time and dynamically adjust the input parameters based on a preset algorithm. The preset algorithm includes adjusting the output voltage or current of the photovoltaic panel at a preset period, detecting the power change trend to gradually approach the maximum power point, and determining the voltage and current values ​​corresponding to the maximum power point by calculating the relationship between the conductance increment and the instantaneous conductance under the current voltage based on the power characteristics of the photovoltaic panel.

[0037] In some embodiments, when the illumination is stable, an algorithm that adjusts the voltage and current according to a preset period can be adopted, namely the perturbation observation method.

[0038] Specifically, the MPPT tracking unit collects the output voltage U and current I of the photovoltaic panel in real time, calculates the current power P=U*I, and stores the current power value as a reference. It adjusts the output voltage or current of the photovoltaic panel at preset intervals (e.g., 0.1 seconds), collects the adjusted voltage and current again, and calculates the new power P'. It compares P' with the reference power P. If P' equals P, it indicates that the current state is at MPP, and no adjustment is made in the next cycle. If P' is greater than P, it indicates that the current adjustment direction is approaching MPP, and the adjustment continues in the same direction in the next cycle. If P' is less than P, it indicates that the state deviates from MPP, and the adjustment is reversed in the next cycle. This process is repeated to gradually approach MPP, stabilizing the photovoltaic panel at its maximum output power.

[0039] In some embodiments, when illumination changes rapidly, an algorithm based on the relationship between conductivity increment and instantaneous conductivity can be adopted, namely the incremental conductivity method.

[0040] Specifically, the MPPT tracking unit calculates the instantaneous conductance G=I / U and conductance increment ΔG=ΔI / ΔU of the photovoltaic panel, where ΔI and ΔU are the current and voltage differences before and after the change. Based on the power characteristics of the photovoltaic cell, when the photovoltaic panel operates at its maximum power point (MPP), ΔG equals -G, meaning the conductance increment equals the negative of the instantaneous conductance. If ΔG is greater than -G, it indicates that the current voltage is lower than the MPP voltage, requiring an increase in voltage; if ΔG is less than -G, it indicates that the current voltage is higher than the MPP voltage, requiring a decrease in voltage. Based on the judgment result, the MPPT tracking unit adjusts the circuit parameters of the photovoltaic input DC-DC module, changing the operating voltage of the photovoltaic panel until ΔG≈-G, at which point the photovoltaic panel operates at its maximum power point. The circuit parameters include the duty cycle of the switching transistors.

[0041] In some embodiments, the DC-DC output module may include an MPPT simulation curve unit. The MPPT simulation curve unit is used to simulate various curves to adapt to the MPPT tracking mode of different inverters, and by adjusting the curve power magnitude and combining the detection results of smart meters, it realizes the self-generation and self-consumption function on the grid side.

[0042] Specifically, the MPPT simulation curve unit has a variety of preset MPPT tracking curve models built in, such as voltage-power curves and current-power curves, which correspond to the MPPT tracking characteristics of different brands and models of photovoltaic inverters on the market.

[0043] In some embodiments, when a photovoltaic inverter is connected to the system, the MPPT simulation curve unit automatically matches and outputs the corresponding simulation curve by identifying the inverter model or its MPPT parameters, ensuring that the inverter can efficiently receive the electrical energy transmitted by the DC-DC output module. The MPPT simulation curve unit receives real-time detection data from the smart meter and dynamically adjusts the power level of the simulation curve based on the data. The detection data includes the grid's allowable power supply and the user's real-time electricity consumption.

[0044] In some embodiments, when the smart meter detects that the user's electricity consumption is greater than the photovoltaic power generation, the MPPT simulation curve unit increases the curve power to increase the energy transmission to the inverter; when the electricity consumption is less than the power generation and the grid allows surplus power to be fed into the grid, the MPPT simulation curve unit decreases the curve power to guide some of the electrical energy to the battery for storage through the battery bidirectional DC-DC module, avoiding energy waste caused by grid limitations; when the grid does not allow surplus power to be fed into the grid, the MPPT simulation curve unit further reduces the curve power to ensure that the power generation only meets the load demand, and all excess energy is stored in the battery, realizing self-generation and self-consumption, as well as surplus energy storage function.

[0045] For example, a user uses a photovoltaic inverter. The MPPT simulation curve unit simulates the curve and transmits it to the inverter. If the smart meter detects that the current user's electricity consumption is 2kW, while the photovoltaic power generation is 3kW, and the grid does not allow surplus power to be fed into the grid, the MPPT simulation curve unit will adjust the power of the simulation curve to 2kW to ensure that 2kW of power is used by the load. The remaining 1kW is transmitted to the battery bidirectional DC-DC module through the DC bus module to charge the battery and avoid energy waste.

[0046] In some embodiments, the DC bus module may include capacitors and a buffer filter unit. The capacitors are used to maintain a stable DC voltage; the buffer filter unit is used to suppress voltage and current fluctuations and noise.

[0047] In some embodiments, the capacitor element may include a large-capacity electrolytic capacitor or a film capacitor, connected in parallel with the DC bus. When the photovoltaic input power suddenly increases, such as when the sunlight intensifies, the capacitor element quickly absorbs and stores excess electrical energy to prevent a sudden rise in bus voltage; when the photovoltaic power suddenly decreases or the load suddenly increases, such as when a high-power appliance is started, the capacitor releases the stored electrical energy to replenish the energy gap and prevent a sudden drop in bus voltage.

[0048] In some embodiments, the buffer filter unit may include an LC filter circuit composed of an inductor and a capacitor, which is connected in series with the DC bus. When the high-frequency ripple generated during photovoltaic power generation and battery charging and discharging passes through the LC filter circuit, the inductor impedes current changes, and the capacitor absorbs voltage fluctuations, thus smoothing the voltage and current waveforms output from the bus.

[0049] In some embodiments, the buffer filter unit may further include a common-mode inductor and a differential-mode capacitor. The common-mode inductor and differential-mode capacitor are used to suppress external electromagnetic interference from entering each module through the DC bus, ensuring the accuracy of the detection data from the MPPT tracking unit.

[0050] In some embodiments, the DC bus module may further include an overvoltage and overcurrent protection device. When the bus voltage exceeds a voltage threshold (e.g., 450V) or the current is too high, the overvoltage and overcurrent protection device cuts off the fault source, preventing damage to capacitor components and other modules and ensuring system safety. The overvoltage and overcurrent protection device includes a varistor and a fuse.

[0051] In some embodiments, the bidirectional DC-AC module may include a load control unit and a load backup power unit. The load control unit is used to control the power supply to the load and to switch the system load between grid-connected mode and off-grid mode; the load backup power unit is used to supply power to the load through the photovoltaic power output from the photovoltaic panel or the electrical energy stored in the battery when the mains power fails.

[0052] In some embodiments, the load control unit may include relays and smart switches, connecting to the loads via relays or smart switches to distribute power according to load priority. Load priority may include primary loads and secondary loads. Primary loads are high-priority loads, including medical equipment and indoor lighting equipment; secondary loads are low-priority loads, including peripheral lighting equipment. For example, when the battery level is below a threshold, power to secondary loads is automatically cut off to prioritize the operation of primary loads. The load control unit monitors the real-time power consumption of each load using current sensors. When the total load exceeds the system's inverter capacity, it gradually disconnects devices according to priority from low to high to avoid overload.

[0053] In some embodiments, when a mains power outage is detected, the load control unit switches to off-grid mode to maintain stable output voltage and frequency. The electrical energy extracted by the photovoltaic input DC-DC module is transmitted to the bidirectional DC-AC module via the DC bus module. The load backup power unit inverts it into AC power for the load to use, and excess electrical energy is used to charge the battery via the battery bidirectional DC-DC module.

[0054] refer to Figure 2 Based on the above embodiments, as another optional embodiment, the photovoltaic input DC-DC module, DC-DC output module, battery bidirectional DC-DC module, DC bus module, and bidirectional DC-AC module all include multiple parallel-configured sub-modules. The overall inverter power of the system is adjusted by increasing or decreasing the number of parallel sub-modules. The sub-modules establish communication connections through a CAN bus. Through distributed collaborative control logic and a preset election mechanism, a master module is determined from each sub-module based on the status information of each sub-module. The master module is used to uniformly control each sub-module.

[0055] In this embodiment, a submodule refers to an independent functional unit that has the same function as the main module, such as the photovoltaic input DC-DC module and the DC-DC output module. This system uses multiple submodules of the same type connected in parallel to linearly adjust the output power of the corresponding main module, thereby dynamically changing the overall inverter power of the system to adapt to different photovoltaic installation capacities and load requirements, while simplifying system expansion and retrofitting processes.

[0056] Among them, the number of sub-modules of the photovoltaic input DC-DC module corresponds to the number of photovoltaic panels; the number of sub-modules of the DC bus module corresponds to the number of sub-modules of the photovoltaic input DC-DC module; the number of sub-modules of the battery bidirectional DC-DC module corresponds to the number of battery packs; the number of sub-modules of the DC-DC output module corresponds to the number of sub-modules of the DC bus module; and the number of sub-modules of the bidirectional DC-AC module corresponds to the number of loads.

[0057] For example, when the user load increases from 3kW to 6kW, the bidirectional DC-AC module includes two parallel 3kW rated power sub-modules, increasing the total inverter power to 6kW.

[0058] In this embodiment of the application, the CAN bus refers to the communication bus used for data interaction between various sub-modules. It has the characteristics of strong anti-interference ability and high real-time performance. It undertakes the transmission tasks of synchronization control frames, status feedback frames and power allocation instructions between the main module and the sub-modules, and is the core communication carrier for realizing distributed collaborative control.

[0059] In this embodiment, the distributed collaborative control logic refers to the preset control rules used to schedule the work of each submodule. By determining the master module from the submodules, the master module uniformly manages the timing and power allocation, and the submodules provide feedback on their operating status, a master-slave collaborative control architecture is formed, avoiding power conflicts caused by the disordered operation of multiple modules.

[0060] In this embodiment, the main module refers to the core control unit selected from the parallel sub-modules, which has the capabilities of global timing calibration, instruction generation, and fault scheduling. The operating status of the main module determines the system's collaborative efficiency, and a preset election mechanism ensures that it has a good health status and uniqueness, avoiding control node failure or conflict.

[0061] In this embodiment, the preset election mechanism refers to preset rules used to determine the main module. The main module is selected based on the status information of the sub-modules, using a sorting logic of health status and hardware identifiers. The triggering conditions for the preset election mechanism include the system's first power-on, a current main module failure, or a communication interruption, ensuring the reliability and uniqueness of the main module's control.

[0062] In this embodiment, the status information refers to the set of operating parameters uploaded in real time by each submodule, including at least the health status and unique hardware identifier of the submodule. The health status includes the output current deviation and operating temperature of each submodule, reflecting the operational stability of the submodule.

[0063] Specifically, upon system power-on, or when the current main module sends a fault code or communication is interrupted, any normal submodule triggers a re-election process. Each submodule sends an election request frame, containing hardware identifiers and health status. Each submodule receives election request frames from other modules, locally generates a list of candidate main modules, and sorts them in descending order of health status and ascending order of hardware identifiers. Priority is given to health status; when sorting by health status, the module with the smallest output current deviation takes precedence; if output current deviations are the same, the module with the lowest operating temperature takes precedence; under the same health status, the module with the smallest hardware identifier takes precedence. The candidate submodule ranked first sends a main module confirmation frame, and other submodules respond with confirmation response frames after receiving the frame, completing the election.

[0064] Based on the above embodiments, as another optional embodiment, the distributed collaborative control logic includes: the master module sending synchronization control frames to each sub-module via the CAN bus, the synchronization control frames being used to calibrate the working timing of each sub-module; each sub-module sending status feedback frames to the master module via the CAN bus, the master module adjusting the power distribution command based on the status feedback frames.

[0065] In this embodiment, the synchronization control frame refers to a control signal periodically sent by the main module via the CAN bus, including an operating mode code and a timing reference value. The operating mode code distinguishes between grid-connected and off-grid modes; the timing reference value is a system operation timestamp in milliseconds. The synchronization control frame is used to calibrate the operating timing of each submodule, such as the MPPT tracking cycle of the photovoltaic input DC-DC submodule and the charge / discharge switching time of the battery bidirectional DC-DC submodule, ensuring coordinated operation of multiple submodules.

[0066] In this embodiment of the application, the status feedback frame refers to the operating status signal periodically sent by each submodule through the CAN bus, including the submodule output current, output voltage and fault code, so that the main module can grasp the operating status of the submodule in real time and adjust the power distribution command accordingly.

[0067] In this embodiment of the application, the power allocation command refers to the control command generated by the main module based on the status feedback frames of each sub-module, which clarifies the output power target value and mode switching requirements of each sub-module.

[0068] In some embodiments, under grid-connected mode, the main module sets the MPPT period through a synchronization control frame, and each photovoltaic input DC-DC submodule needs to synchronously start the MPPT disturbance at the beginning of each MPPT period.

[0069] In some embodiments, the submodule sends a status feedback frame. The main module receives and obtains the output current of the target submodule, and adjusts the discharge power of the target submodule in the power allocation command based on the difference between the output current and the rated current. If the status feedback frame of the target submodule contains a fault code, such as an over-temperature fault code, the main module instructs other submodules to share the power of the target submodule to avoid system shutdown due to overheating of a single module.

[0070] Based on the above embodiments, as another optional embodiment, the system generates a power allocation command based on the photovoltaic input power uploaded by the photovoltaic input DC-DC submodule, the battery SOC uploaded by the battery bidirectional DC-DC submodule, and the total load power uploaded by the bidirectional DC-AC submodule. The system then adjusts the output power of each photovoltaic input DC-DC submodule, battery bidirectional DC-DC submodule, and bidirectional DC-AC submodule based on the power allocation command. When the photovoltaic input power is greater than or equal to a first threshold, the excess photovoltaic power is allocated to the battery for energy storage through the battery bidirectional DC-DC submodule. When the photovoltaic input power is less than the first threshold, the battery energy is distributed to the load through the bidirectional DC-DC submodule and the bidirectional DC-AC submodule, and the energy distribution ratio is adjusted based on the load.

[0071] In this embodiment of the application, photovoltaic input power refers to the output power of the photovoltaic panel that is collected and uploaded in real time by the photovoltaic input DC-DC submodule through the MPPT function. It reflects the real-time supply capacity of photovoltaic energy and is used to enable the system to determine whether the energy is sufficient and whether energy storage or supplementation is needed.

[0072] In this embodiment of the application, the battery SOC refers to the percentage of remaining battery charge that is monitored and uploaded in real time by the battery bidirectional DC-DC submodule. It reflects the battery's energy storage capacity, affects the charging and discharging power limits of the battery in the power allocation command, and ensures battery life.

[0073] In this embodiment of the application, the total load power refers to the sum of all load power consumed by the bidirectional DC-AC submodule in real time, including load priority information, which is used to enable the system to calculate the energy gap and allocate battery energy.

[0074] In this embodiment of the application, the first threshold refers to a power threshold dynamically determined by the system based on the photovoltaic input power, battery SOC and total load power, used to determine whether the photovoltaic power is sufficient.

[0075] In this embodiment of the application, the energy allocation ratio refers to the battery energy allocation rule set by the system based on load priority, which prioritizes the energy needs of high-priority loads and allocates energy to low-priority loads according to the remaining energy ratio, so as to ensure the continuous power supply of core loads when photovoltaic power is insufficient.

[0076] In some embodiments, the photovoltaic input DC-DC submodule monitors the output voltage and current of the photovoltaic panel in real time through the MPPT function, calculates and uploads the real-time total photovoltaic power, and marks the power change trend; the battery bidirectional DC-DC submodule monitors the battery SOC, individual cell voltage, and temperature in real time, calculates the current maximum chargeable power, and uploads it via the CAN bus. For example, when SOC < 30%, the maximum chargeable power is 0.8C of the battery's rated capacity; when SOC ≥ 80%, the maximum chargeable power is reduced to 0.3C of the battery's rated capacity to protect the battery.

[0077] In some embodiments, loads can be divided into primary loads, secondary loads, and tertiary loads according to their priority from high to low. The bidirectional DC-AC submodule collects the power of each load branch, pre-stores the load priority table, and uploads the total load power and priority to the main module.

[0078] The formula for calculating the first threshold is: When the battery SOC is less than 50% and the photovoltaic power is increasing, the first threshold is equal to the total load power * a. When 50% ≤ Battery SOC < 70%, the first threshold = total load power; When the battery SOC is ≥70% or the photovoltaic power is decreasing, the first threshold = total load power * b; Where a and b are the first threshold coefficient and the second threshold coefficient, respectively.

[0079] In some embodiments, if the first-level load accounts for more than 50% of the total load, the first threshold is further lowered; a and b can be 0.8 and 1.2 respectively.

[0080] Specifically, when the main module determines that the photovoltaic input power is greater than or equal to the first threshold, the main module calculates the excess power = total photovoltaic power - total load power, generates an energy storage command, and sends it to the battery bidirectional DC-DC submodule via the CAN bus; the battery bidirectional DC-DC submodule allocates the energy storage power according to its own quantity and battery status.

[0081] If the battery SOC < 30%, the bidirectional DC-DC submodule of the battery will operate at full power and adopt constant current charging mode, that is, current = battery rated capacity * 0.8C; If the battery SOC is between 30% and 70%, the battery bidirectional DC-DC submodule retains 30% of the power as a buffer, which is temporarily stored through the DC bus capacitor. A pulse charging mode is adopted, that is, charging for 5 minutes and pausing for 1 minute to reduce battery polarization. If the battery SOC is ≥ 70%, only one bidirectional DC-DC submodule is activated for float charging, i.e., power = excess power * 0.1; the remaining excess power is adjusted through the DC-DC output submodule to adjust the MPPT simulation curve and adapt to the output of the photovoltaic inverter to the grid.

[0082] When the main module determines that the photovoltaic input power is less than the first threshold, it calculates the power gap as the first threshold minus the total photovoltaic power, generates a coordinated power replenishment command, and clarifies the battery replenishment ratio and load priority allocation rules. For example, the primary load replenishes 100% of the power gap, the secondary load replenishes 80% of the power gap, and the tertiary load replenishes 50% of the power gap.

[0083] If the battery SOC is greater than or equal to 40%, the bidirectional DC-DC submodule discharges at 90% of the power deficit, leaving 10% as a fluctuation buffer, and matches the battery voltage to the DC bus voltage through a buck-boost topology. If the battery SOC is less than 40%, the bidirectional DC-DC submodule will only discharge at 60% of the power deficit.

[0084] If a primary load is connected, the bidirectional DC-AC submodule maintains its rated power output. If a secondary load is connected, the bidirectional DC-AC submodule will output 80% of its rated power. If a three-level load is connected, the bidirectional DC-AC submodule will output 50% of its rated power.

[0085] Based on the above embodiments, as another optional embodiment, when the photovoltaic input DC-DC submodule is over-supplied, each photovoltaic input DC-DC submodule uploads the maximum power point to the DC-DC output submodule via the CAN bus; Each DC-DC output submodule adjusts the MPPT simulation curve based on its maximum power point and oversizing ratio.

[0086] In some embodiments, after the system is powered on, the main module collects the rated input power of the original photovoltaic inverter and calculates the total photovoltaic input power by using the rated power of each photovoltaic input DC-DC sub-module and the number of parallel connections uploaded by each module. When the total photovoltaic input power > the rated input power of the inverter, it is determined to be an over-sizing state, and the over-sizing ratio = (total photovoltaic input power - rated input power of inverter) / rated input power of inverter × 100%.

[0087] In some embodiments, each photovoltaic input DC-DC submodule performs MPPT tracking and updates its own MPP parameters in real time. The submodule calculates the total photovoltaic MPP power and, combined with the inverter's rated input power, determines the upper limit of the baseline power of the simulation curve; then, it extracts the MPP voltage range of each submodule and limits the voltage range of the simulation curve to this range to ensure matching with the output characteristics of the photovoltaic panel.

[0088] In some embodiments, if the MPP power P of a photovoltaic input DC-DC submodule is... mTo reduce power consumption, the DC-DC output submodule adds local power attenuation characteristics to the corresponding voltage segment in the analog curve, avoiding misjudging the overall MPP by the inverter due to local shading and ensuring stable energy extraction.

[0089] When a user adds photovoltaic panels, the total power increases, and the over-sizing ratio increases. The main module broadcasts the new over-sizing ratio via the CAN bus, and the DC-DC output sub-modules dynamically increase according to the correlation between the over-sizing ratio and the inverter's rated power. For example, for every 20% increase in the over-sizing ratio, the power limit of the simulated curve increases by 10% of the inverter's rated power.

[0090] Based on the above embodiments, as another optional embodiment, the second end of each battery bidirectional DC-DC submodule is connected to multiple parallel battery packs, and each battery bidirectional DC-DC submodule monitors the ripple characteristics of the capacitor voltage of the DC bus submodule. Based on the ripple characteristics, each battery's bidirectional DC-DC submodule adjusts the charging and discharging current.

[0091] In some embodiments, each battery bidirectional DC-DC submodule extracts ripple characteristics through voltage sampling signals. Ripple characteristics may include ripple amplitude, ripple frequency, and ripple slope. Ripple amplitude refers to the difference between the peak and trough values ​​of the voltage fluctuation, reflecting the stability of the bus voltage; ripple frequency refers to the dominant frequency and harmonic distribution of the fluctuation signal, relating to the abrupt changes in photovoltaic input or load; and ripple slope refers to the rate of change of voltage fluctuation, characterizing the severity of the disturbance.

[0092] In some embodiments, based on ripple characteristics, the battery bidirectional DC-DC submodule classifies the ripple state into a normal state, a slight disturbance state, and a severe disturbance state. In the normal state, the fingerprint characteristic parameters are within a preset stable range, corresponding to scenarios where there are no significant fluctuations in photovoltaic input and load. In the slight disturbance state, the fingerprint characteristic parameters exceed the stable range but do not reach the critical value, corresponding to fluctuations caused by brief changes in illumination or small load start-ups and shutdowns. In the severe disturbance state, the fingerprint characteristic parameters significantly exceed the critical value, corresponding to drastic fluctuations caused by sudden changes in photovoltaic power or sudden start-ups and shutdowns of large loads.

[0093] Each battery bidirectional DC-DC submodule dynamically adjusts the charging and discharging current based on the ripple state determination result and the real-time state of charge and health status of the connected battery pack.

[0094] In some embodiments, the bidirectional DC-DC submodule of the battery operates at a preset reference charging and discharging current, and the current distribution deviation of each bidirectional DC-DC submodule of the battery is controlled within a preset range through a current sharing control mechanism.

[0095] When a slight disturbance is detected, the battery bidirectional DC-DC submodule activates the compensation mode. If it is in charging mode, the charging current is temporarily reduced proportionally to reduce the impact of photovoltaic input on the bus and to buffer excess energy using the energy storage of the DC bus capacitor. If it is in discharging mode, the discharging current is slightly increased proportionally to make up for the energy gap caused by load fluctuations and to suppress bus voltage drops.

[0096] When a severe disturbance is detected, the battery bidirectional DC-DC submodule activates its emergency response mechanism. If it is charging, it immediately disconnects the charging circuit to prevent the bus voltage from dropping rapidly due to a sudden drop in photovoltaic input, and simultaneously sends a disturbance alarm signal to the main module. If it is discharging, it increases the discharge current to the maximum allowable range and synchronizes with other battery bidirectional DC-DC submodules via the CAN bus to increase the current in tandem. The total discharge power is increased proportionally to quickly fill the energy gap, and the buffering effect of the DC bus capacitor suppresses voltage fluctuations.

[0097] Example 1 A residential photovoltaic energy storage system adopts a modular architecture, including: 2 sets of photovoltaic input DC-DC sub-modules with a total power of 3kW, supporting MPPT tracking; Two bidirectional DC-DC sub-modules for batteries, numbered A and B, each sub-module connects to two sets of parallel batteries. A connects to a 48V / 100Ah lithium battery pack and a 110V / 50Ah lead-acid battery pack, and B connects to a battery pack of the same specifications. DC bus submodule, including 4000μF filter capacitor, rated voltage 380V; A bidirectional DC-AC submodule with a 1.5kW primary load and a 2kW secondary load.

[0098] Furthermore, the ripple status is normal, with only the primary load operating, the DC bus capacitor voltage ripple amplitude ≤3V, the frequency stable at around 100Hz, the slope ≤0.5V / ms, the photovoltaic input power 2.5kW, the load power 0.3kW, and the system is in charging state.

[0099] At this time, the battery bidirectional DC-DC submodules A and B operate at the reference charging current. Through current sharing control, A outputs 40A and B outputs 38A, storing the excess 2.2kW power into the battery pack.

[0100] Example 2 With the parameters of the residential photovoltaic energy storage system unchanged, the ripple state is a slight disturbance. The photovoltaic power decreases by 10%, the ripple amplitude increases to 4V, the frequency shows a 200Hz component, and the slope is 0.8V / ms.

[0101] At this time, submodule A drops from 40A to 35A and submodule B drops from 38A to 33A, reducing the impact of photovoltaic input fluctuations on the bus; at the same time, the DC bus capacitor releases about 0.2kW of buffer energy to maintain stable power supply to the load.

[0102] Example 3 With the parameters of the residential photovoltaic energy storage system unchanged, the ripple state is a severe disturbance. When the load power increases from 0.3kW to 2.3kW, the ripple amplitude suddenly rises to 7V, the frequency contains a 600Hz high-frequency component, and the slope is 1.5V / ms.

[0103] At this point, the system switches to discharge mode, and submodules A and B increase the discharge current to 60A, increasing the total discharge power from 2kW to 2.4kW. In conjunction with the DC bus capacitor releasing 0.1kW of energy, the 2kW load gap is quickly filled. The bidirectional DC-AC submodule is notified via the CAN bus to prioritize ensuring that the primary load power remains unchanged, while the secondary load power is temporarily limited to 1.8kW to avoid overload.

[0104] Based on the above embodiments, as another optional embodiment, when the system triggers off-grid mode, each bidirectional DC-AC submodule establishes direct communication with the photovoltaic input DC-DC submodule through the CAN bus, and supplies the photovoltaic input power to the load through the DC bus; Based on the difference between photovoltaic input power and load demand, each battery bidirectional DC-DC submodule generates supplementary power; Based on the rate of change of photovoltaic input power, each battery bidirectional DC-DC submodule adjusts its supplementary power.

[0105] In some embodiments, the difference between the photovoltaic input power and the load demand is: ΔP(t)=P load (t)-P PV (t) P Batt (t)=max{ΔP(t),0} Where ΔP(t) refers to the difference between the photovoltaic input power and the load demand at time t, P load (t) refers to the total load demand power at time t, P PV (t) refers to the total photovoltaic input power at time t, P Batt (t) refers to the battery replenishment power at time t.

[0106] When ΔP(t)≤0, the photovoltaic power is sufficient, and the battery does not need to be replenished. Batt (t)=0.

[0107] The photovoltaic power change rate r(t) is: r(t) = [P PV (t)-P PV[(t-Δt)] / Δt The buffer coefficient k(t) is: k(t) = {k1, k2, k3} When |r(t)|≤r1, k(t)=k1; when r1<|r(t)|≤r2, k(t)=k2; when |r(t)|>r2, k(t)=k3.

[0108] Where r1 and r2 are both rate of change thresholds.

[0109] Final supplementary power = min{P Batt (t)*(1+k(t)),P max (t)} Among them, P max (t) refers to the maximum allowable output power of the battery at time t.

[0110] refer to Figure 3 , Figure 3 This illustration shows a flowchart of a photovoltaic energy storage and bidirectional inverter conversion method provided in an embodiment of this application. This method can be implemented using a computer program, a microcontroller, or run on a photovoltaic energy storage and bidirectional inverter conversion system. The computer program can be integrated into a computer device or run as a standalone application. Specifically, the method includes steps S100 to S500, as follows: S100: Monitors the output voltage and current of the photovoltaic panel through the photovoltaic input DC-DC module, dynamically adjusts the input parameters based on the preset algorithm to track the maximum power point, converts the electrical energy generated by the photovoltaic panel into a voltage that is compatible with the DC bus module, and transmits it to the DC bus module. Specifically, the MPPT tracking unit of the photovoltaic input DC-DC module collects the voltage and current of the photovoltaic panel in real time, uses the perturbation observation method to fine-tune the output voltage, and detects the power change trend to approach the maximum power point; or it calculates the relationship between the conductance increment and the instantaneous conductance through the incremental conductance method to accurately locate the MPP.

[0111] The S200 DC bus module maintains a stable DC voltage through capacitor elements and suppresses voltage and current fluctuations and noise through buffer filtering units, and performs unified transfer of received electrical energy. Specifically, the capacitors in the DC bus module absorb voltage fluctuations to maintain a stable DC voltage; the buffer filter unit suppresses high-frequency ripple and reduces noise interference through LC circuits. Power is uniformly distributed to each module via the bus, supporting parallel access from multiple sources such as photovoltaics and batteries, while protection devices prevent overvoltage and overcurrent.

[0112] The S300 DC-DC output module obtains power from the DC bus module, simulates the MPPT curve of the photovoltaic inverter through the MPPT simulation curve unit, adjusts the power of the curve and combines the detection results of the smart meter to transmit the power to the photovoltaic inverter, realizing self-generation and self-consumption on the grid side. Specifically, the MPPT simulation curve unit of the DC-DC output module generates a voltage-power curve adapted to the photovoltaic inverter. Based on the grid status and load demand fed back by the smart meter, the curve power is adjusted. For example, when surplus electricity cannot be fed into the grid, the curve power is reduced to the load demand, directing the excess energy to the battery for self-consumption.

[0113] The S400 battery bidirectional DC-DC module monitors the battery's status parameters through an integrated management unit. When charging is required, the electrical energy from the DC bus module is converted into a voltage and current suitable for the battery via a buck-boost unit to charge the battery. When discharging is required, the electrical energy stored in the battery is converted and transmitted to the DC bus module via a buck-boost unit. Specifically, the integrated management unit of the battery bidirectional DC-DC module monitors the battery voltage, temperature and charge in real time. During charging, the DC bus voltage is reduced to the battery's matching voltage through the buck-boost unit; during discharging, the battery voltage is boosted and transmitted to the DC bus, and the current is dynamically adjusted according to the load demand.

[0114] The S500 bidirectional DC-AC module obtains power from the DC bus module, supplies power to the load through the load control unit, and controls the load to switch between grid-connected and off-grid modes according to the mains power status. When the mains power fails, the load backup power unit switches to the photovoltaic power or battery energy storage power supply path to continuously supply power to the load.

[0115] Specifically, the load control unit of the bidirectional DC-AC module supplies power to the load and monitors the mains power status: when the mains power is normal, it operates in grid-connected mode and supplies power in coordination with the grid; when the power is off, it switches to off-grid mode and supplies power through photovoltaic power or battery energy storage, giving priority to ensuring the operation of critical equipment.

[0116] Based on the above embodiments, as another optional embodiment, this application embodiment may further include a computer storage medium, which may store multiple instructions adapted for loading and execution by a processor of a photovoltaic energy storage and bidirectional inverter conversion method of the above embodiments. For the specific execution process, please refer to the detailed description of the above embodiments, which will not be repeated here.

[0117] Based on the above embodiments, as another optional embodiment, this application embodiment may further include an electronic device. The electronic device may include: at least one processor, at least one communication bus, a user interface, at least one network interface, and a memory.

[0118] The communication bus is used to enable communication between these components.

[0119] The user interface may include a display screen and a camera. Optional user interfaces may also include standard wired interfaces and wireless interfaces.

[0120] The network interface may include standard wired interfaces and wireless interfaces (such as Wi-Fi interfaces).

[0121] The processor may include one or more processing cores. It connects to various parts of the server via various interfaces and lines, executing instructions, programs, code sets, or instruction sets stored in memory, and accessing data stored in memory to perform various server functions and process data. Optionally, the processor may be implemented using at least one of the following hardware forms: Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), and Programmable Logic Array (PLA). The processor may integrate one or more of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content displayed on the screen; and the modem handles wireless communication. It is understood that the modem may also be implemented as a separate chip without being integrated into the processor.

[0122] The memory may include random access memory (RAM) or read-only memory. Optionally, the memory may include a non-transitory computer-readable storage medium. The memory can be used to store instructions, programs, code, code sets, or instruction sets. The memory may include a program storage area and a data storage area, wherein the program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-described method embodiments, etc.; the data storage area may store data involved in the above-described method embodiments, etc. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor. As a computer storage medium, the memory may include an operating system, a network communication module, a user interface module, and an application program for a photovoltaic energy storage and bidirectional inverter conversion method.

[0123] In electronic devices, the user interface is primarily used to provide an input interface for users and to acquire user input data. The processor can be used to call an application program stored in memory that describes a photovoltaic energy storage and bidirectional inverter conversion method. When executed by one or more processors, this causes the electronic device to perform one or more methods as described in the above embodiments. It should be noted that, for the foregoing method embodiments, for the sake of simplicity, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0124] 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 in other embodiments.

[0125] In the various embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some service interface; the indirect coupling or communication connection between apparatuses or units may be electrical or other forms.

[0126] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0127] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0128] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned memory includes various media capable of storing program code, such as USB flash drives, portable hard drives, magnetic disks, or optical disks.

[0129] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Other embodiments of this disclosure will readily conceive of those skilled in the art upon consideration of the specification and the disclosure of practical truths.

[0130] This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A photovoltaic energy storage and bidirectional inverter conversion system, characterized in that, include: Photovoltaic inverters, photovoltaic input DC-DC modules, DC-DC output modules, battery bidirectional DC-DC modules, bidirectional DC-AC modules, and DC bus modules; The first end of the photovoltaic input DC-DC module is connected to the photovoltaic panel, and the second end is connected to the DC bus module. The photovoltaic input DC-DC module includes an MPPT DC input unit. The first end of the DC-DC output module is connected to the DC bus module, and the second end is connected to the photovoltaic inverter; The first end of the battery bidirectional DC-DC module is connected to the DC bus module, and the second end is connected to the battery. The first end of the bidirectional DC-AC module is connected to the DC bus module, the second end is connected to the load, and the third end is connected to the photovoltaic inverter.

2. The photovoltaic energy storage and bidirectional inverter conversion system according to claim 1, characterized in that: The photovoltaic input DC-DC module, DC-DC output module, battery bidirectional DC-DC module, DC bus module and bidirectional DC-AC module all include multiple parallel-configured sub-modules. The overall inverter power of the system can be adjusted by increasing or decreasing the number of parallel sub-modules. The sub-modules establish communication connections through a CAN bus. Based on the status information of each sub-module, a master module is determined through distributed collaborative control logic and a preset election mechanism. The master module is used to uniformly control each sub-module.

3. The photovoltaic energy storage and bidirectional inverter conversion system according to claim 2, characterized in that, The distributed collaborative control logic includes: The main module sends synchronization control frames to each of the sub-modules other than the main module via the CAN bus. The synchronization control frames are used to calibrate the working timing of each of the sub-modules. Each of the sub-modules other than the main module sends a status feedback frame to the main module via the CAN bus, and the main module adjusts the power allocation command based on the status feedback frame.

4. The photovoltaic energy storage and bidirectional inverter conversion system according to claim 3, characterized in that: The system generates the power allocation command based on the photovoltaic input power uploaded by the photovoltaic input DC-DC submodule, the battery state of charge uploaded by the battery bidirectional DC-DC submodule, and the total load power uploaded by the bidirectional DC-AC submodule, and adjusts the output power of each of the photovoltaic input DC-DC submodule, battery bidirectional DC-DC submodule, and bidirectional DC-AC submodule based on the power allocation command; When the photovoltaic input power is greater than or equal to the first threshold, the excess photovoltaic power is distributed to the battery for energy storage through the battery bidirectional DC-DC submodule. When the photovoltaic input power is less than the first threshold, the energy of the battery is distributed to the load through the bidirectional DC-DC submodule and the bidirectional DC-AC submodule, and the energy distribution ratio is adjusted based on the load.

5. The photovoltaic energy storage and bidirectional inverter conversion system according to claim 2, characterized in that: When the photovoltaic input DC-DC submodule is over-supplied, each of the photovoltaic input DC-DC submodules uploads the maximum power point to the DC-DC output submodule via the CAN bus; Each of the DC-DC output submodules adjusts the MPPT simulation curve based on its maximum power point and overfitting ratio.

6. The photovoltaic energy storage and bidirectional inverter conversion system according to claim 2, characterized in that: The second end of each battery bidirectional DC-DC submodule is connected to multiple parallel battery packs, and each battery bidirectional DC-DC submodule monitors the ripple characteristics of the capacitor voltage of the DC bus submodule; Based on the ripple characteristics, each of the battery bidirectional DC-DC submodules adjusts the charging and discharging current.

7. The photovoltaic energy storage and bidirectional inverter conversion system according to claim 6, characterized in that: When the system triggers off-grid mode, each bidirectional DC-AC submodule establishes direct communication with the photovoltaic input DC-DC submodule via the CAN bus, and supplies the photovoltaic input power to the load via the DC bus; Based on the difference between the photovoltaic input power and the load demand, each of the battery bidirectional DC-DC sub-modules generates supplementary power; Based on the rate of change of the photovoltaic input power, each of the battery bidirectional DC-DC submodules adjusts the supplementary power.

8. A photovoltaic energy storage and bidirectional inverter conversion method, characterized in that, Applied to the photovoltaic energy storage and bidirectional inverter system as described in any one of claims 1-7, comprising: The photovoltaic input DC-DC module monitors the output voltage and current of the photovoltaic panel, dynamically adjusts the input parameters based on a preset algorithm to track the maximum power point, converts the electrical energy generated by the photovoltaic panel into a voltage that is compatible with the DC bus module, and transmits it to the DC bus module. The DC bus module maintains a stable DC voltage through capacitor elements and suppresses voltage and current fluctuations and noise through a buffer filter unit, thus performing unified transfer of the received electrical energy. The DC-DC output module obtains electrical energy from the DC bus module, simulates the MPPT curve of the photovoltaic inverter through the MPPT simulation curve unit, adjusts the curve power and combines the detection results of the smart meter to transmit electrical energy to the photovoltaic inverter, realizing self-generation and self-consumption on the grid side; The battery bidirectional DC-DC module monitors the battery's status parameters through an integrated management unit. When charging is required, the electrical energy from the DC bus module is converted into a voltage and current suitable for the battery via a buck-boost unit to charge the battery. When discharging is required, the electrical energy stored in the battery is converted and transmitted to the DC bus module via a buck-boost unit. The bidirectional DC-AC module obtains power from the DC bus module, supplies power to the load through the load control unit, and controls the load to switch between grid-connected mode and off-grid mode according to the mains power status; when the mains power fails, the load backup power unit switches to photovoltaic power or battery energy storage power supply path to continuously supply power to the load.

9. An electronic device, characterized in that, It includes a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory to cause the electronic device to perform the method as described in claim 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores multiple instructions that are adapted to be loaded by a processor and executed as described in claim 8.

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