Energy storage system direct current coupling MPPT energy control strategy and method

Abstract

The invention relates to the technical field of electric power engineering, and discloses a direct-current coupling MPPT energy control strategy and method based on an energy storage system, and the method comprises the steps: configuring a power coordination controller on a direct-current coupling bus of the energy storage system; determining a total power demand reference value of the power coordination controller through the power of the power grid side electric meter; the real-time state information of the battery unit, the total output power of the photovoltaic MPPT unit and the total power demand reference value of the power coordination controller are fused, and a power coordination control strategy of the power coordination controller for the energy storage system is generated; and synchronously adjusting the output power limit of the photovoltaic MPPT unit and the output power set value of the grid-connected inverter based on a power cooperative control strategy. The energy utilization rate of the energy storage system can be improved.

Description

A DC-coupled MPPT energy control strategy and method based on energy storage system Technical Field

[0001] This invention relates to an energy control strategy and method based on DC-coupled MPPT of an energy storage system, belonging to the field of power engineering technology. Background Technology

[0002] MPPT energy control is a maximum power point tracking control method applied to the DC-coupled architecture of energy storage systems. Its core principle is to track the maximum output power of renewable energy generation equipment such as photovoltaic panels in real time, achieving efficient energy capture and transmission through dynamic adjustment of circuit parameters. In the field of power engineering technology, MPPT energy control aims to solve the problems of insufficient energy recovery and supply-demand imbalance in scenarios such as photovoltaic output fluctuations and changes in load demand. It ensures that energy storage systems can stably acquire the maximum amount of renewable energy under different operating conditions, while simultaneously guaranteeing DC-side voltage stability and energy transmission efficiency.

[0003] Currently, existing technologies often employ a fixed power allocation strategy when coordinating photovoltaic MPPT energy, battery charging and discharging power, and grid-connected inverter output power. However, this strategy fails to fully consider battery health status, photovoltaic power fluctuations, and actual grid demands, and lacks multi-dimensional dynamic response capabilities. This static control method is difficult to adapt to changing weather conditions and complex operating conditions in real time, resulting in significant energy losses and a reduction in the overall energy utilization rate of the energy storage system. Summary of the Invention

[0004] This invention provides an energy control strategy and method based on DC-coupled MPPT for energy storage systems, the main purpose of which is to improve the energy utilization rate of energy storage systems.

[0005] To achieve the above objectives, this invention provides an energy control strategy and method based on a DC-coupled MPPT (Multi-Pulse Test Photovoltaic Power PT) system for energy storage, comprising: configuring a power coordination controller on the DC-coupled bus of the energy storage system, wherein the power coordination controller is used to manage the power flow between photovoltaic MPPT units, battery units, and grid-connected inverters on the DC-coupled bus; monitoring the power of the grid-side meters at the grid connection point in real time to determine the total power demand reference value corresponding to the power coordination controller; monitoring the total output power of the photovoltaic MPPT units based on the DC-coupled bus and determining the real-time status information of the battery units; fusing the real-time status information, the total power demand reference value, and the total output power to generate a power coordination control strategy for the energy storage system by the power coordination controller; and synchronously adjusting the output power limit of the photovoltaic MPPT units and the output power setpoint of the grid-connected inverter based on the power coordination control strategy to complete the energy control of the energy storage system.

[0006] Optionally, the step of integrating the real-time status information, the total power demand reference value, and the total output power to generate the power coordination controller's power coordination control strategy for the energy storage system includes: determining the power allocation benchmark, safe operating boundary, and current power difference of the energy storage system based on the real-time status information and the total power demand reference value; calculating the MPPT limiting power of the power coordination controller for the energy storage system based on the current power difference and the safe operating boundary; determining the power output value of the grid-connected inverter by combining the total power demand reference value and the number of grid-connected inverters operating online in the energy storage system; and generating the power coordination controller's power coordination control strategy for the energy storage system based on the MPPT limiting power and the power output value.

[0007] Optionally, calculating the MPPT limiting power of the energy storage system by the power coordination controller based on the current power difference and the safe operating boundary includes: determining the current system power regulation mode of the energy storage system and resolving the maximum allowable charging power of the battery cells of the energy storage system from the safe operating boundary; when the system power regulation mode is a charging priority mode, calculating the MPPT limiting power of the energy storage system based on the current power difference and the maximum allowable charging power.

[0008] Optionally, determining the power output value of the grid-connected inverter by combining the total power demand reference value with the number of grid-connected inverters operating online in the energy storage system includes: calculating the power adjustment value of a single grid-connected inverter based on the current power difference and the number of online inverters; determining the reference output power of a single grid-connected inverter, and calculating the initial output power setting value of a single grid-connected inverter based on the reference output power and the power adjustment value; and performing operating condition correction processing on the initial output power setting value according to the real-time state of charge of the battery units in the energy storage system to obtain the power output value of the grid-connected inverter.

[0009] Optionally, the system power regulation modes include charging priority mode and grid priority mode.

[0010] Optionally, after calculating the MPPT limiting power of the energy storage system based on the current power difference and the maximum allowable charging power, the method further includes: when the system power regulation mode is grid-feed priority mode, setting the MPPT limiting power to the rated power value of the grid-connected inverter of the energy storage system to complete the grid-feeding behavior of the grid-connected inverter.

[0011] Optionally, the real-time monitoring of the power meter power at the grid connection point to determine the total power demand reference value corresponding to the power coordination controller includes: parsing the preset grid interaction target value of the power coordination controller; and determining the total power demand reference value corresponding to the power coordination controller based on the power deviation value between the real-time value of the power meter power and the preset grid interaction target value.

[0012] Optionally, configuring a power coordination controller on the DC coupling bus of the energy storage system includes: deploying an embedded controller on the electrical connection node of the DC coupling bus; and establishing data connection channels and control links with the photovoltaic MPPT unit, battery unit and grid-connected inverter in the energy storage system through the communication bus of the embedded controller, so as to complete the configuration of the power coordination controller.

[0013] Optionally, the data connection channels include an MPPT power acquisition channel, a battery status acquisition channel, and an inverter status acquisition channel.

[0014] Optionally, the control link sends MPPT power limiting commands to the photovoltaic MPPT unit and power output commands to the grid-connected inverter through the embedded controller, so as to form a closed-loop control of the power flow of the energy storage system.

[0015] In the solution described in this invention, the system verifies the synchronous regulation effect by monitoring key performance indicators, such as the stability of the DC bus voltage, which is directly related to the electrical safety and lifespan of capacitors and battery equipment; the tracking accuracy of the grid interaction power to the target value reflects the system's responsiveness and compatibility to grid commands / demands; and the comprehensive power and loss analysis of each unit can evaluate the real-time operating efficiency of the system; furthermore, the controller performs rolling optimization of the power coordination control strategy based on these multi-dimensional feedback data in the next control cycle, thus forming a closed-loop control system that continuously pursues safety, compatibility, and efficient coordination.

[0016] Compared to the problems described in the background art, the embodiments of the present invention, by configuring a power coordination controller on the DC coupling bus of the energy storage system, can realize energy sharing and coordinated control among multiple MPPT units; furthermore, the embodiments of the present invention, by integrating the real-time status information, the total power demand reference value, and the total output power, generate a power coordination controller for the energy storage system, which allows the power allocation process to directly align with the multi-dimensional constraints of battery safety boundaries, grid interaction targets, and photovoltaic power generation capacity, ensuring precise alignment of the power control strategy with battery health status, grid dispatch requirements, and changes in solar irradiance, thereby improving the energy utilization rate of the energy storage system; in addition, the present invention... Not only can it simultaneously support the expansion of multiple MPPTs to achieve adaptive access to photovoltaic capacity, but it can also flexibly adapt to the power requirements of different application scenarios, possessing higher compatibility and stronger scalability. Finally, the embodiments of the present invention, based on the power collaborative control strategy, synchronously adjust the output power limit of the photovoltaic MPPT unit and the output power setpoint of the grid-connected inverter to complete the energy control of the energy storage system. This can achieve accurate adaptation of power distribution and real-time operating conditions, which not only avoids the problem of rigid regulation deviating from the battery safety boundary and grid interaction requirements, but also ensures the balanced sharing of power among the units of the system, thereby improving the overall energy utilization rate of the energy storage system. Attached Figure Description

[0017] Figure 1 is a flowchart illustrating the DC-coupled MPPT energy control strategy and method based on an energy storage system according to an embodiment of the present invention; Figure 2 is a DC-coupled MPPT grid-connected topology diagram illustrating the DC-coupled MPPT energy control strategy and method based on an energy storage system according to an embodiment of the present invention; Figure 3 is a power coordination principle diagram illustrating the DC-coupled MPPT energy control strategy and method based on an energy storage system according to an embodiment of the present invention; Figure 4 is a logical schematic diagram illustrating the power coordination control strategy illustrating the DC-coupled MPPT energy control strategy and method based on an energy storage system according to an embodiment of the present invention; Figure 5 is a schematic diagram of the modules implementing the DC-coupled MPPT energy control strategy and system based on an energy storage system according to an embodiment of the present invention; Figure 6 is a schematic diagram of the computer equipment implementing the DC-coupled MPPT energy control strategy and system based on an energy storage system according to an embodiment of the present invention.

[0018] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0021] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0022] In this specification and the appended claims, there may be multiple ways of expressing the same technical feature or technical term, such as using a superordinate generalization, a subordinate limitation, or a synonym substitution. Those skilled in the art can clearly understand the substantially the same technical meaning referred to by different expressions based on their professional knowledge and in conjunction with the overall content of the specification and the drawings. The differences in different expressions are only reflected in the diversity of words and do not constitute a substantial modification or limitation to the technical solution, nor will they affect the certainty of the scope of protection of this patent claim or the full disclosure of the technical content of the specification.

[0023] This application provides an energy control strategy and method based on DC-coupled MPPT (Multi-Level Phototransfer) of an energy storage system. The executing entity of the energy control strategy and method based on DC-coupled MPPT of an energy storage system includes, but is not limited to, at least one of the following electronic devices that can be configured to execute the method provided in this application embodiment: a server, a terminal, etc. In other words, the energy control method based on DC-coupled MPPT of an energy storage system can be executed by software or hardware installed on a terminal device or a server device. The server includes, but is not limited to, a single server, a server cluster, a cloud server, or a cloud server cluster.

[0024] Referring to Figure 1, a flowchart illustrating an embodiment of the energy control strategy and method based on DC-coupled MPPT of an energy storage system provided by the present invention is shown. In this embodiment, the energy control strategy and method based on DC-coupled MPPT of an energy storage system includes: S1, configuring a power coordination controller on the DC coupling bus of the energy storage system.

[0025] The embodiments of the present invention enable energy sharing and coordinated control among multiple MPPT units by configuring a power coordination controller on the DC coupling bus of the energy storage system.

[0026] The energy storage system refers to a complete set of devices with energy storage and release functions, which includes at least battery cells, a battery management system, a power conversion system, and necessary thermal management and safety protection components. For example, the system can be a residential energy storage cabinet for smoothing fluctuations in photovoltaic power generation, or a containerized energy storage power station for peak-valley arbitrage in industrial and commercial parks. The DC coupling bus refers to a common node that electrically connects all DC-side equipment at the DC circuit level, and its voltage level is determined by the system design. For example, photovoltaic modules are connected to this bus through DC-DC converters, battery cells are connected to this bus through bidirectional DC-DC converters, and grid-connected inverters draw power directly from this bus. The power coordination controller refers to a computing and decision-making unit embedded in the main controller of the energy storage system. This controller, through a combination of hardware circuits and software programs, collects real-time status data of the grid, photovoltaics, and batteries, runs a built-in power allocation algorithm, and issues coordination control commands to the photovoltaic maximum power point tracking unit and the grid-connected inverter.

[0027] As an embodiment of the present invention, configuring a power coordination controller on the DC coupling bus of the energy storage system includes: deploying an embedded controller on the electrical connection node of the DC coupling bus; and establishing data connection channels and control links with the photovoltaic MPPT unit, battery unit and grid-connected inverter in the energy storage system through the communication bus of the embedded controller, so as to complete the configuration of the power coordination controller.

[0028] Here, the electrical connection node refers to a specific physical location on the DC coupling bus used to connect power equipment or measuring devices. For example, a copper terminal block on the DC bus specifically reserved for installing a voltage sensor; the embedded controller refers to a dedicated computing device integrating a microprocessor, memory, and input / output interfaces; the communication bus refers to a standardized communication medium connecting various devices in the system to achieve data exchange; the photovoltaic MPPT unit refers to a power conversion device that enables maximum power point tracking of photovoltaic modules; the battery unit refers to the core component constituting the energy storage part of the energy storage system. For example, a battery module composed of 16 lithium-ion cells in a 4-parallel configuration; the grid-connected inverter refers to a power device that achieves bidirectional conversion between DC and AC power; the data connection channel refers to a unidirectional communication path for transmitting monitoring data and status information. For example, the battery management system periodically sends battery state-of-charge data messages via the CAN bus, which include SOC value, voltage and current measurements, and alarm status; the control link refers to a bidirectional communication path for transmitting control commands. For example, a closed-loop command path formed by the power coordination controller sending power setting commands to the grid-connected inverter via Ethernet and receiving power output confirmation signals returned by the inverter.

[0029] Specifically, the data connection channels include an MPPT power acquisition channel, a battery status acquisition channel, and an inverter status acquisition channel. The control link sends MPPT power limiting commands to the photovoltaic MPPT unit and power output commands to the grid-connected inverter through the embedded controller, thereby forming a closed-loop control of the power flow of the energy storage system and improving the operating efficiency of the energy storage system.

[0030] Referring to Figure 2, this is a DC-coupled MPPT grid-connected topology diagram based on an energy control strategy and method for an energy storage system according to an embodiment of the present invention. The figure shows that the energy storage converter CAIO1 is connected to the first photovoltaic panel via MPPT1, and CAIO2 is connected to the second photovoltaic panel via MPPT2. Each MPPT unit is physically independent, but they are electrically connected in parallel through the DC coupling bus, forming a unified DC energy pool. Based on this topology, the energy storage system can not only simultaneously support the expansion of multiple MPPTs to achieve adaptive access to photovoltaic capacity, but also flexibly adapt to the power requirements of different application scenarios, possessing higher compatibility and stronger scalability. For example, when the system needs to be expanded, only a new "CAIOx + MPPTx" unit needs to be connected in parallel to the DC bus, without changing the core control architecture or communication link of the existing equipment, thus achieving plug-and-play photovoltaic capacity and adaptive power allocation.

[0031] S2. Monitor the power of the grid-side meters at the grid connection point in real time to determine the reference value of the total power demand corresponding to the power coordination controller.

[0032] This invention, through real-time monitoring of the power meter power at the grid connection point, determines the reference value of the total power demand corresponding to the power coordination controller, ensuring that the power coordination controller can achieve safe and efficient control under different photovoltaic configurations and diverse grid interaction strategies.

[0033] The grid connection point refers to the physical interface location where the energy storage system is electrically connected to the public power grid and exchanges energy, typically located at the junction of the AC output side of the grid-connected inverter and the power grid distribution line. The grid-side meter power refers to the instantaneous active power value measured by a bidirectional energy metering device configured at the grid connection point. Optionally, the bidirectional energy metering device can be a smart meter with bidirectional communication function or a Hall effect sensor that supports power direction recognition. The total power demand reference value refers to the system total power control target value dynamically calculated by the power coordination controller based on the grid-side meter power.

[0034] As an embodiment of the present invention, the real-time monitoring of the power meter power at the grid connection point to determine the total power demand reference value corresponding to the power coordination controller includes: parsing the preset grid interaction target value of the power coordination controller; and determining the total power demand reference value corresponding to the power coordination controller based on the power deviation value between the real-time value of the power meter power and the preset grid interaction target value.

[0035] The preset grid interaction target value refers to the grid power control target pre-set by the power coordination controller according to the system operation requirements. For example, in the self-consumption mode, the preset grid interaction target value can be set to a zero power interaction target to achieve complete local consumption of photovoltaic power generation; in the grid support mode, it can be set to a negative value to respond to peak shaving commands and feed power to the grid, or set to a dynamic value to participate in grid frequency regulation; in the economic optimization mode, the target value can be dynamically set according to the time-of-use electricity price to maximize revenue. It should be noted that the preset grid interaction target value is not a fixed value, but a setpoint that can be dynamically switched according to the operating strategy to reflect the external strategy compatibility of the control system; the real-time value refers to the instantaneous reading of active power actually measured by the bidirectional power metering device configured at the grid connection point at the sampling time; the power deviation value refers to the algebraic difference between the real-time power value of the grid-side meter and the preset grid interaction target value. Optionally, the total power demand reference value corresponding to the power coordination controller can be determined by a proportional-integral controller.

[0036] Referring to Figure 3, this is a power coordination principle diagram of a DC-coupled MPPT energy control strategy and method based on an energy storage system according to an embodiment of the present invention. The diagram uses the real-time reading Pmeter of the grid meter as key feedback, which is compared with the zero setpoint to generate a power error ε(t). A PI controller composed of a proportional coefficient Kp and an integral coefficient Ki dynamically calculates this error and outputs a precise reference value Pref for the total system power demand. Specifically: at the control level, the proportional term Kp·ε(t) provides a fast response to counteract disturbances caused by changes in photovoltaic power or load; the integral term Ki·∫ε(τ)dτ eliminates steady-state deviations by accumulating historical errors, ensuring that Pmeter is accurately stabilized at zero over a long period; finally, the precisely calculated power command Pref is sent to the power conversion system for execution, coordinating the charging and discharging actions of the battery to balance the power flow inside and outside the system. This diagram formally defines, from an algorithmic principle perspective, the dynamic process of transforming high-level grid interaction strategies into executable control commands. It is important to emphasize that the Pref generated in this process is only the total power requirement of the system. In the subsequent power allocation stage, this requirement will be strictly placed under the safety and equipment efficiency constraints such as battery safety power boundary and inverter capacity limit for secondary optimization allocation.

[0037] S3. Based on the DC coupling bus, monitor the total output power of the photovoltaic MPPT unit and determine the real-time status information of the battery unit.

[0038] This invention, through monitoring the total output power of the photovoltaic MPPT unit based on the DC coupling bus, provides crucial photovoltaic power generation capacity sensing data for real-time energy scheduling of energy storage systems. The photovoltaic MPPT unit refers to a power conversion device combination that maximizes energy extraction from photovoltaic modules through a DC-DC converter circuit and a maximum power point tracking algorithm. For example, in a 20 kW photovoltaic array, a complete photovoltaic MPPT unit can be formed by four 5 kW rated capacity MPPT controllers connected in parallel. The total output power refers to the sum of the instantaneous power generated by all parallel-operating photovoltaic MPPT units on the DC bus, which can be obtained through synchronous measurement and calculation by voltage and current sensors on the DC bus side.

[0039] Furthermore, this embodiment of the invention determines the real-time status information of the battery cells based on the DC coupling bus, accurately revealing the real-time energy reserves and adjustability within a safe range of the energy storage system. This provides crucial state input for optimizing power allocation under safety constraints. The real-time status information refers to characteristic parameters of the battery cells, such as individual module voltage, individual voltage difference, temperature, current, rate of change of expansion force, and impedance, collected in real time by integrating multi-dimensional sensors. These parameters serve as important constraints for MPPT power limiting. For example, when an abnormal temperature or deterioration in voltage balance of a battery module is detected, the system will automatically reduce the MPPT limiting power to prevent overcharging, overheating, or local overload of the battery. Optionally, the multi-dimensional sensors can be voltage sensors, temperature sensors, etc., integrated on the battery surface.

[0040] As an embodiment of the present invention, determining the real-time status information of the battery cell based on the DC coupling bus includes: dividing the charging and discharging operating range of the battery cell according to the voltage ripple characteristics of the DC coupling bus; statistically analyzing the instantaneous power change gradient in the charging and discharging operating range; acquiring real-time measured values ​​of the terminal voltage and charging and discharging current of the battery cell; analyzing the dynamic response relationship between the instantaneous power change gradient and the real-time measured values; and determining the real-time status information of the battery cell based on the dynamic response relationship.

[0041] The voltage ripple characteristic refers to the periodic fluctuation component superimposed on the DC voltage on the DC coupling bus. For example, during the operation of a photovoltaic MPPT unit, the periodic fluctuation of the bus voltage within ±5% of the rated value is caused by the switching frequency. The battery unit refers to the combination of electrochemical units that constitute the basic energy storage module of the energy storage system. For example, a 51.2V battery module composed of 16 3.2V lithium iron phosphate cells connected in series. The charge / discharge operating range refers to the battery operating state range divided according to the voltage ripple characteristic. For example, it is divided into constant current charging region, constant voltage charging region, float charging region, and discharge operating region. The instantaneous power change gradient refers to the rate of change of battery power per unit time. The terminal voltage refers to the potential difference between the positive and negative electrodes of the battery unit. For example, the terminal voltage of a lithium battery under rated battery charge state is 3.7V. The charge / discharge current refers to the current value flowing into or out of the battery unit. For example, the current is positive during charging and negative during discharging. The real-time measurement value refers to the instantaneous reading of battery parameters directly collected by sensors. For example, real-time current values ​​acquired by a Hall current sensor and real-time voltage values ​​acquired by a voltage sampling circuit; the dynamic response relationship refers to the correspondence between battery parameters and time. For example, the transient response characteristics generated by the step change of terminal voltage with charge / discharge current, including dynamic indicators such as response time and overshoot.

[0042] Optionally, the charging and discharging operating range in the battery cell can be divided using a fuzzy C-means clustering algorithm; the dynamic response relationship between the instantaneous power change gradient and the real-time measurement value can be analyzed using a transfer function identification algorithm; and the real-time state information of the battery cell can be determined using a SOC estimation method based on an equivalent circuit model.

[0043] S4. Integrate the real-time status information, the total power demand reference value, and the total output power to generate the power coordination controller's power coordination control strategy for the energy storage system.

[0044] This invention, through the fusion of real-time status information, total power demand reference value, and total output power, generates a power coordination controller for the energy storage system. This allows the power allocation process to directly align with multi-dimensional constraints of battery safety boundaries, grid interaction targets, and photovoltaic power generation capacity, significantly improving the system's safety and reliability under complex operating conditions. The power coordination control strategy is a comprehensive control scheme that coordinates power allocation among photovoltaic MPPT units, battery units, and grid-connected inverters in the energy storage system. In this strategy, the system prioritizes using the photovoltaic energy generated by the MPPT for local load power supply, and the remaining power is allocated to the battery units for charging via the DC bus. If the battery is fully charged or charging power is limited, the remaining energy will be further fed back into the grid through the grid-connected inverter (PCS) or used to power other CAIO units, achieving dynamic energy scheduling and global optimization within the system.

[0045] As an embodiment of the present invention, the step of integrating the real-time status information, the total power demand reference value, and the total output power to generate a power coordination controller for the energy storage system includes: determining the power allocation benchmark, safe operating boundary, and current power difference of the energy storage system based on the real-time status information and the total power demand reference value; calculating the MPPT limiting power of the power coordination controller for the energy storage system based on the current power difference and the safe operating boundary; determining the power output value of the grid-connected inverter by combining the total power demand reference value and the number of grid-connected inverters operating online in the energy storage system; and generating the power coordination controller for the energy storage system based on the MPPT limiting power and the power output value.

[0046] The power allocation benchmark refers to the power allocation basis determined by the power coordination controller based on the grid interaction target and the system state. For example, when the goal is to achieve zero grid interaction, the power allocation benchmark is the total system power reference value required to bring the grid power to zero, which can be achieved through the following formula: ,in, This represents the reference value for the total system power. This indicates the reading of the electricity meter on the grid side. This represents the proportionality coefficient. This represents the reference value for total power demand in the previous cycle. The goal of this formula is to continuously adjust... Ultimately Adjusted to zero to achieve zero grid interaction. The safe operation boundary refers to the set of power and state parameter limits that ensure the safe operation of the energy storage system, including but not limited to the battery state of charge range, the maximum allowable charge and discharge power of the battery, the DC bus voltage fluctuation range, and the inverter output power limit; the current power difference refers to the instantaneous difference between the system's total power demand reference value and the total photovoltaic output power; the MPPT limit power refers to the maximum allowable output power value set by the power coordination controller for the photovoltaic MPPT unit to ensure the safe operation of the system. For example, when the battery is close to full charge, the controller sets the MPPT limit power to the rated power value of the grid-connected inverter to ensure that the photovoltaic power generation energy can be fully fed into the grid through the inverter; the grid-connected inverter refers to the power conversion device that connects the DC bus and the AC grid. For example, a three-phase inverter with a full-bridge topology; the number of online operating inverters refers to the total number of grid-connected inverters currently in a dispatchable state; the power output value refers to the active power control target value set by the power coordination controller for the grid-connected inverter. For example, during battery charging, when the photovoltaic power generation exceeds the battery's acceptable charging power, the controller sets a power output value of -5kW for the grid-connected inverter, instructing it to feed the remaining 5kW of photovoltaic energy into the grid.

[0047] Optionally, the safe operating boundary of the energy storage system can be determined by thermal simulation software; the power coordination controller's power coordination control strategy for the energy storage system can be generated by a multi-objective optimization algorithm.

[0048] In another embodiment of the present invention, the step of calculating the MPPT limiting power of the energy storage system by the power coordination controller based on the current power difference and the safe operating boundary includes: determining the current system power regulation mode of the energy storage system, and resolving the maximum allowable charging power of the battery cells of the energy storage system from the safe operating boundary; wherein, the system power regulation mode includes a charging priority mode and a grid priority mode; when the system power regulation mode is the charging priority mode, the MPPT limiting power of the energy storage system is calculated based on the current power difference and the maximum allowable charging power.

[0049] The system power regulation mode refers to the power allocation strategy selected by the power coordination controller based on the real-time operating status of the energy storage system. For example, when the battery state of charge is below 95%, a charging priority mode is used; when the battery state of charge reaches or exceeds 95%, it switches to a grid-feeding priority mode. The battery unit refers to the basic unit constituting the energy storage portion of the energy storage system. The maximum allowable charging power refers to the maximum acceptable charging power value under the premise of ensuring battery safety. The charging priority mode is an operating strategy that prioritizes maximizing battery charging. For example, in this mode, the system prioritizes using photovoltaic power generation for battery charging, and only when the charging power reaches the battery's maximum allowable charging power will the remaining photovoltaic energy be fed into the grid through a grid-connected inverter. The grid-feeding priority mode is an operating strategy that prioritizes grid energy interaction. For example, in this mode, the system prioritizes feeding photovoltaic power generation into the grid through a grid-connected inverter, and only when the grid's feed-in capacity is limited will the remaining energy be used for battery charging.

[0050] It should be noted that when the system power regulation mode is grid-priority mode, the power coordination controller directly sets the MPPT limiting power of the photovoltaic MPPT unit to the rated power value of the grid-connected inverter to ensure that the photovoltaic energy can be fully fed into the grid after meeting the local load.

[0051] For example, the MPPT-limited power of the photovoltaic MPPT unit is calculated using the following formula. It should be noted that this calculation method is only one possible method and does not affect the implementation of the basic scheme above:

[0052] in, This indicates the MPPT limiting power of the photovoltaic MPPT unit. Indicates the maximum allowable charging power of the battery cell. This represents the total output power of the photovoltaic MPPT unit. This indicates the current power difference.

[0053] It should be noted that the above formula uses a minimum value function to arbitrate the two key objectives of battery safe charging boundary and grid power tracking requirements in real time, effectively coordinating the competitive relationship between battery safety protection, grid-friendly interaction, and system power balance. Specifically, the formula achieves an equivalent representation of the total system power demand by adding the total MPPT output power to the power difference, enabling the MPPT power limiting command to synchronously respond to dynamic changes in the grid interaction state. For example, when the grid requires a reduction in feed-in power ( Reduced Even if the battery still has charging capability, the formula will automatically reduce the MPPT limit power to prioritize grid dispatching needs. Furthermore, by introducing the battery's maximum allowable charging power as a hard constraint, the formula establishes a direct mapping of the electrochemical safety boundary to the power control level. This allows for a leap in energy management strategies from simple power balancing to cell-level safety protection, significantly improving the system's operational reliability under complex conditions such as battery aging and abnormal temperatures. For example, when the battery temperature exceeds 45°C... When the voltage drops to 50% of the rated value, the system immediately limits the MPPT power to a safe range, effectively preventing the risk of battery thermal runaway; when the battery voltage balance deteriorates, it dynamically adjusts the power level. Numerical values ​​can enable preventative protection for weak battery cells.

[0054] As another embodiment of the present invention, determining the power output value of the grid-connected inverter by combining the total power demand reference value and the number of grid-connected inverters operating online in the energy storage system includes: calculating the power adjustment value of a single grid-connected inverter based on the current power difference and the number of online inverters; determining the reference output power of a single grid-connected inverter, and calculating the initial output power setting value of a single grid-connected inverter based on the reference output power and the power adjustment value; and performing operating condition correction processing on the initial output power setting value according to the real-time state of charge of the battery units in the energy storage system to obtain the power output value of the grid-connected inverter.

[0055] The power adjustment value refers to the amount of power regulation that a single grid-connected inverter needs to undertake. For example, the power adjustment value of a single grid-connected inverter... ,in, The formula represents the current power difference, and n represents the number of online inverters. This formula improves the equipment utilization and operating efficiency of multi-unit parallel systems and avoids single-unit overload by evenly distributing the current power deficit to each currently online grid-connected inverter. The reference output power refers to the basic output power of the grid-connected inverter without considering power adjustment values. For example, in discharge mode, the reference output power is zero; in charging mode, the reference output power can be set to the output power of the corresponding MPPT unit. The initial output power setting value refers to the target output power value of the grid-connected inverter obtained through preliminary calculation. It should be noted that the calculation logic of the initial output power setting value needs to be determined according to different operating conditions of the system, specifically including: in the case of no photovoltaic access, the initial output power setting value... Based on the total power demand reference value Number of inverters in operation The decision is made jointly, and the calculation formula is as follows: Under conditions where photovoltaic power is connected, the initial output power setting value is... Based on the total power demand reference value Current instantaneous output power of the photovoltaic MPPT unit and the number of inverters operating online. The decision is made jointly, and the calculation formula is as follows: , If positive, it indicates that the inverter needs to generate additional power; if negative, it indicates that the inverter needs to absorb excess energy. The operating condition correction process refers to the dynamic adjustment process of the power coordination controller on the initial output power setting of the grid-connected inverter based on the real-time state of charge of the battery, in order to achieve a dynamic balance between efficiency optimization and safety boundaries. Specifically, it includes: if the state of charge of the battery cell is lower than the safe charging limit, the initial output power setting remains unchanged, and the system prioritizes using photovoltaic energy for battery charging; if the state of charge of the battery cell reaches or exceeds the safe charging limit, the power allocation strategy is switched. At this time, the controller sets the MPPT limit power to the total rated power of the grid-connected inverter, allowing the photovoltaic cells to generate full power, and the power output value of the grid-connected inverter will be reset to absorb the remaining photovoltaic energy that the battery cannot absorb. Specifically, the system converts the surplus photovoltaic energy generated by the DC-side MPPT into AC power through an inverter and prioritizes supplying it to local loads on the AC-side bus. If the local loads cannot fully absorb the power, the surplus power is fed into the grid or used to supplement the power of other controllable AC loads (CAIO), thereby achieving flexible scheduling and efficient utilization of MPPT energy on the AC bus.

[0056] It should be noted that when facing severe weather-induced fluctuations in photovoltaic output, the system power state will change significantly. The power coordination control strategy still exhibits strong robustness and grid compatibility under this condition. In this scenario, the execution logic of the power coordination control strategy is as follows: the system prioritizes the use of available photovoltaic energy and battery storage energy to ensure continuous power supply to critical loads; the power coordination controller will recalculate power allocation based on real-time updated, more conservative safety operating boundaries. It limits the battery discharge power to prevent damage from over-discharge. At this point, the MPPT power limit calculation fully considers the actual photovoltaic output, while the grid-connected inverter's power output command focuses on accurately controlling power interaction with the grid while meeting load requirements and protecting the batteries. This maintains system balance and meets grid dispatch and power quality requirements, demonstrating its high adaptability and compatibility with complex operating conditions and the external grid environment.

[0057] To clearly illustrate the dynamic allocation of power flow and the multi-objective collaborative control mechanism in the energy storage system, refer to Figure 4, which is a logical schematic diagram of the power collaborative control strategy based on the DC-coupled MPPT energy control strategy and method for energy storage systems provided in an embodiment of the present invention. This figure abstracts core elements such as grid interaction targets, battery status, photovoltaic output, and inverter clusters into logical nodes, and constructs a closed-loop control topology using power flow and control command flow, intuitively demonstrating the complete decision-making process of the system from target setting to power execution. Specifically, the control system uses real-time grid meter readings as key feedback and dynamically generates a reference value for the system's total power demand through proportional-integral calculations. Its core control objective has multiple compatibility features: In default mode, the objective is to zero meter readings to achieve "zero interaction" with the grid, thereby maximizing photovoltaic self-consumption; upon receiving explicit grid dispatch instructions, such as peak shaving and valley filling or power limits, this reference value can be dynamically overridden or corrected, switching the system to "grid-supported mode," thus achieving compatibility with different grid service demands; at the power allocation execution level, the system always prioritizes the use of photovoltaic energy: if photovoltaic power generation has surplus after meeting battery charging requirements, it is converted from DC to AC by the power inverter (PCS) and prioritized for supplying local loads; any remaining surplus can be fed back into the grid. Conversely, if photovoltaic power generation is insufficient to support load demand and charging targets, the system distributes power equally according to the number of online PCS, instructing the PCS to draw power from the battery for precise supplementation, jointly making up for the power deficit.

[0058] S5. Based on the power coordination control strategy, the output power limit of the photovoltaic MPPT unit and the output power setpoint of the grid-connected inverter are adjusted synchronously to complete the energy control of the energy storage system.

[0059] This invention, through a power collaborative control strategy, synchronously adjusts the output power limit of the photovoltaic MPPT unit and the output power setpoint of the grid-connected inverter to achieve energy control of the energy storage system. This enables accurate adaptation of power allocation to real-time operating conditions. It not only incorporates the electrochemical safety boundary of the battery and the grid's scheduling and interaction requirements as core constraints into real-time decision-making, but also optimizes the power flow within the system through a balanced sharing and collaborative synchronization mechanism. Thus, while ensuring operational safety and grid compatibility, it comprehensively improves the overall energy utilization efficiency of the energy storage system.

[0060] The output power limitation refers to the mandatory constraint value on the maximum output power of the photovoltaic MPPT unit. For example, by adjusting the operating point of the MPPT controller, its maximum output power can be dynamically limited from the rated value of 5kW to 3kW to match the real-time charging capability of the battery. The output power setpoint refers to the active power control target value directly assigned to the grid-connected inverter. For example, issuing a -2kW power setpoint command to the grid-connected inverter PCS indicates that it is required to draw power from the DC bus and feed 2kW of power into the grid. The energy control refers to the overall management process of energy flow and power distribution within the energy storage system, including coordinated operations such as priority consumption of photovoltaic power generation, battery charging and discharging power management, and grid interaction power adjustment. Its core objective is to achieve dynamic balance and multi-dimensional optimized operation of the energy storage system under the premise of ensuring system operation safety and meeting grid interaction rules, including maximizing the renewable energy consumption rate, optimizing battery life and system cycle efficiency. Specifically: First, based on real-time collected system status data, the power coordination controller calculates the power coordination control strategy within a single control cycle, generating a coordinated control instruction set containing MPPT power limiting instructions and grid-connected inverter PCS output power instructions. Then, the controller encapsulates these two types of instructions within the same communication frame using a timestamp synchronization mechanism and, based on the energy storage system's device communication protocol, synchronously distributes them to all photovoltaic MPPT units and grid-connected inverter PCS via broadcast or multicast. Finally, each controlled device receives and parses the instructions within a preset synchronization time window, and the photovoltaic MPPT unit dynamically adjusts its maximum power point tracking algorithm's power limit according to the MPPT power limiting instructions. Simultaneously, the grid-connected inverter PCS updates its active power outer loop control setpoint based on the output power command of the grid-connected inverter PCS. Finally, the system verifies the synchronous regulation effect by monitoring key performance indicators, such as the stability of the DC bus voltage, which is directly related to the electrical safety and lifespan of capacitors and battery equipment; the tracking accuracy of grid interaction power to the target value reflects the system's responsiveness and compatibility to grid commands / demands; and the comprehensive power and loss analysis of each unit can evaluate the real-time operating efficiency of the system. Furthermore, in the next control cycle, the controller performs rolling optimization of the power coordination control strategy based on these multi-dimensional feedback data, thus forming a closed-loop control system that continuously pursues safety, compatibility, and efficient coordination.

[0061] Optionally, a distributed consensus algorithm can be used to synchronously adjust the output power limit of the photovoltaic MPPT unit and the output power setting value of the grid-connected inverter.

[0062] Figure 5 shows a functional block diagram of an energy control strategy and system based on DC coupling MPPT of an energy storage system according to the present invention.

[0063] The energy control strategy and system 200 based on DC-coupled MPPT of an energy storage system described in this invention can be installed in an electronic device. Depending on the functions implemented, the energy control strategy and system based on DC-coupled MPPT of an energy storage system may include a control management module 201, a power grid monitoring module 202, a photovoltaic monitoring module 203, a strategy generation module 204, and a power execution module 205. The module described in this invention can also be called a unit, which refers to a series of computer program segments that can be executed by the processor of an electronic device and can perform a fixed function, and are stored in the memory of the electronic device.

[0064] In this embodiment of the invention, the functions of each module / unit are as follows: The control management module 201 is used to configure a power coordination controller on the DC coupling bus of the energy storage system, wherein the power coordination controller is used to manage the power flow between the photovoltaic MPPT unit, the battery unit, and the grid-connected inverter on the DC coupling bus; the grid monitoring module 202 is used to monitor the power of the grid-side meter at the grid connection point in real time to determine the total power demand reference value corresponding to the power coordination controller; the photovoltaic monitoring module 203 is used to monitor the total output power of the photovoltaic MPPT unit based on the DC coupling bus and determine the real-time status information of the battery unit; the strategy generation module 204 is used to integrate the real-time status information, the total power demand reference value, and the total output power to generate a power coordination control strategy for the energy storage system by the power coordination controller; the power execution module 205 is used to synchronously adjust the output power limit of the photovoltaic MPPT unit and the output power setpoint of the grid-connected inverter based on the power coordination control strategy to complete the energy control of the energy storage system.

[0065] In detail, the modules in the DC-coupled MPPT energy control strategy, method and system 200 of the energy storage system described in the embodiments of the present invention adopt the same technical means as the DC-coupled MPPT energy control strategy and method of the energy storage system described in Figure 1 above, and can produce the same technical effect, which will not be repeated here.

[0066] In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram is shown in Figure 6. The computer device includes a processor, memory, network interface, and database connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile and / or volatile storage media and internal memory. The non-volatile storage media stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with external clients via a network connection. When the computer program is executed by the processor, it implements the functions or steps of a DC-coupled MPPT energy control strategy and method based on an energy storage system on the server side.

[0067] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it performs the following steps: configuring a power coordination controller on the DC-coupled bus of an energy storage system, wherein the power coordination controller manages the power flow between photovoltaic MPPT units, battery units, and a grid-connected inverter on the DC-coupled bus; monitoring the power of the grid-side meter at the grid connection point in real time to determine the total power demand reference value corresponding to the power coordination controller; monitoring the total output power of the photovoltaic MPPT units based on the DC-coupled bus and determining the real-time status information of the battery units; fusing the real-time status information, the total power demand reference value, and the total output power to generate a power coordination control strategy for the energy storage system by the power coordination controller; and synchronously adjusting the output power limit of the photovoltaic MPPT units and the output power setpoint of the grid-connected inverter based on the power coordination control strategy to complete the energy control of the energy storage system.

[0068] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When executed by a processor, the computer program performs the following steps: configuring a power coordination controller on the DC coupling bus of an energy storage system, wherein the power coordination controller is used to manage the power flow between photovoltaic MPPT units, battery units, and grid-connected inverters on the DC coupling bus; monitoring the power of the grid-side meters at the grid connection point in real time to determine the total power demand reference value corresponding to the power coordination controller; monitoring the total output power of the photovoltaic MPPT units based on the DC coupling bus and determining the real-time status information of the battery units; fusing the real-time status information, the total power demand reference value, and the total output power to generate a power coordination control strategy for the energy storage system by the power coordination controller; and synchronously adjusting the output power limit of the photovoltaic MPPT units and the output power setpoint of the grid-connected inverter based on the power coordination control strategy to complete the energy control of the energy storage system.

[0069] It should be noted that the functions or steps that can be implemented by the computer-readable storage medium or computer device described above can be referred to the relevant descriptions on the server side and client side in the foregoing method embodiments. To avoid repetition, they will not be described one by one here.

[0070] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods.

[0071] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0073] Finally, it should be noted that in the above embodiments, each embodiment can be combined with each other or independent. Deleting any one of them will not affect the technical implementation of other embodiments. The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A DC-coupled MPPT energy control strategy and method based on an energy storage system, characterized in that, The method includes: configuring a power coordination controller on the DC coupling bus of the energy storage system, wherein the power coordination controller is used to manage the power flow between the photovoltaic MPPT unit, the battery unit, and the grid-connected inverter on the DC coupling bus; monitoring the power of the grid-side meter at the grid connection point in real time to determine the total power demand reference value corresponding to the power coordination controller; monitoring the total output power of the photovoltaic MPPT unit based on the DC coupling bus and determining the real-time status information of the battery unit; fusing the real-time status information, the total power demand reference value, and the total output power to generate a power coordination control strategy for the energy storage system by the power coordination controller; and synchronously adjusting the output power limit of the photovoltaic MPPT unit and the output power setpoint of the grid-connected inverter based on the power coordination control strategy to complete the energy control of the energy storage system.

2. The energy control strategy and method based on DC-coupled MPPT of energy storage system as described in claim 1, characterized in that, The process of integrating the real-time status information, the total power demand reference value, and the total output power to generate a power coordination control strategy for the energy storage system by the power coordination controller includes: determining the power allocation benchmark, safe operating boundary, and current power difference of the energy storage system based on the real-time status information and the total power demand reference value; calculating the MPPT limiting power of the energy storage system by the power coordination controller based on the current power difference and the safe operating boundary; determining the power output value of the grid-connected inverter by combining the total power demand reference value and the number of grid-connected inverters operating online in the energy storage system; and generating the power coordination control strategy for the energy storage system by the power coordination controller based on the MPPT limiting power and the power output value.

3. The energy control strategy and method based on DC-coupled MPPT of energy storage system as described in claim 2, characterized in that, The step of calculating the MPPT limiting power of the energy storage system by the power coordination controller based on the current power difference and the safe operating boundary includes: determining the current system power regulation mode of the energy storage system and resolving the maximum allowable charging power of the battery cells of the energy storage system from the safe operating boundary; when the system power regulation mode is the charging priority mode, calculating the MPPT limiting power of the energy storage system based on the current power difference and the maximum allowable charging power.

4. The energy control strategy and method based on DC-coupled MPPT of energy storage system as described in claim 2, characterized in that, The step of determining the power output value of the grid-connected inverter by combining the total power demand reference value with the number of grid-connected inverters operating online in the energy storage system includes: calculating the power adjustment value of a single grid-connected inverter based on the current power difference and the number of online inverters; determining the reference output power of a single grid-connected inverter, and calculating the initial output power setting value of a single grid-connected inverter based on the reference output power and the power adjustment value; and performing operating condition correction processing on the initial output power setting value according to the real-time state of charge of the battery units in the energy storage system to obtain the power output value of the grid-connected inverter.

5. The energy control strategy and method based on DC-coupled MPPT of energy storage system as described in claim 3, characterized in that, The system power regulation modes include charging priority mode and grid priority mode.

6. The energy control strategy and method based on DC-coupled MPPT of an energy storage system as described in claim 3, characterized in that, After calculating the MPPT limiting power of the energy storage system based on the current power difference and the maximum allowable charging power, the method further includes: when the system power regulation mode is grid-feed priority mode, setting the MPPT limiting power to the rated power value of the grid-connected inverter of the energy storage system to complete the grid-feeding behavior of the grid-connected inverter.

7. The energy control strategy and method based on DC-coupled MPPT of energy storage system as described in claim 1, characterized in that, The method of real-time monitoring of the power meter power at the grid connection point to determine the total power demand reference value corresponding to the power coordination controller includes: parsing the preset grid interaction target value of the power coordination controller; and determining the total power demand reference value corresponding to the power coordination controller based on the power deviation value between the real-time value of the power meter power and the preset grid interaction target value.

8. The energy control strategy and method based on DC-coupled MPPT of energy storage system as described in claim 1, characterized in that, The configuration of the power coordination controller on the DC coupling bus of the energy storage system includes: deploying an embedded controller on the electrical connection node of the DC coupling bus; and establishing data connection channels and control links with the photovoltaic MPPT unit, battery unit and grid-connected inverter in the energy storage system through the communication bus of the embedded controller, so as to complete the configuration of the power coordination controller.

9. The energy control strategy and method based on DC-coupled MPPT of an energy storage system as described in claim 8, characterized in that, The data connection channels include an MPPT power acquisition channel, a battery status acquisition channel, and an inverter status acquisition channel.

10. The energy control strategy and method based on DC-coupled MPPT of an energy storage system as described in claim 8, characterized in that, The control link sends MPPT power limiting commands to the photovoltaic MPPT unit and power output commands to the grid-connected inverter through the embedded controller, thereby forming a closed-loop control of the power flow of the energy storage system.

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