Control method and device of energy storage system, energy storage system and storage medium

Abstract

Embodiments of the present application provide a control method and device of an energy storage system, the energy storage system and a storage medium, wherein the energy storage system comprises a load, an energy storage converter, an energy storage battery and a power distribution gateway; the energy storage battery is connected to the energy storage converter, the energy storage converter is connected to the load and the power grid through the power distribution gateway; a switching switch is arranged between the energy storage converter and the power distribution gateway. The method comprises: acquiring a voltage signal of the power grid, and extracting a voltage parameter corresponding to the power grid based on the voltage signal; determining a target state corresponding to the power grid based on the voltage parameter; adjusting the voltage output by the energy storage converter based on the voltage parameter and the target state; and controlling the switching switch to switch states based on the target state, so that the energy storage converter interacts with the load or the power grid. The method is used to solve the problems of power supply voltage interruption and impact current caused by the delay of switch action in the traditional switching mode, and to improve the dynamic adaptability and switching reliability of the system through multi-parameter fusion determination.

Description

Technical Field

[0001] This application relates to the fields of power electronics and energy storage control technology, and in particular to a control method, device, energy storage system and storage medium for an energy storage system. Background Technology

[0002] Residential energy storage systems are the core of home energy management, relying on energy storage batteries, inverters, and distribution gateways to achieve on-grid and off-grid interaction, providing power to critical loads during grid failures. However, traditional switching methods rely on physical switch operations, which are prone to voltage interruptions and surges during grid state transitions, damaging sensitive equipment. In areas with frequent grid failures, users have an increasingly urgent need for reliable and continuous switching.

[0003] Existing grid-connected and off-grid switching technologies have many significant drawbacks. For example, the mechanical and logical delays in switching actions can easily lead to power supply voltage interruptions; the voltage characteristics of energy storage converters and the grid are mismatched, which can easily generate inrush currents; at the same time, the judgment logic based on fixed thresholds is difficult to adapt to the complex operating conditions of grid fluctuations and load changes, which can easily lead to incorrect switching or switching failures, seriously affecting the reliability of system operation and reducing the user experience.

[0004] Existing technologies (such as the scheme disclosed in prior art CN116345504A) propose a method to control the grid-connected switch closing by sampling the grid voltage and converter voltage and controlling them to synchronize. This simplifies the grid-connected switch structure and improves real-time detection to some extent. When grid connection is required, this scheme adjusts the converter voltage according to the grid voltage to achieve synchronization, and then closes the switch. When disconnected from the grid, it first detects grid anomalies, then controls the converter to stabilize the voltage and disconnects the switch. The inherent defect of this control logic is that the physical action of the switch (opening or closing) and the adjustment process of the converter output voltage are separated in timing. Therefore, at the moment of switch action, since the converter output voltage may not be fully matched with the target state (independent grid parameters when disconnected or real-time grid parameters when connected), power supply gaps or voltage and current surges will still inevitably occur, making it impossible to achieve a truly "seamless" switching. Furthermore, its status judgment usually relies on a single voltage parameter threshold comparison. When there are complex disturbances or sudden load changes in the power grid, it is easy to make misjudgments due to a single abnormal signal or rigid judgment logic, which affects the accuracy of switching and system stability. Summary of the Invention

[0005] This application provides a control method, device, energy storage system, and storage medium for an energy storage system, which solves the problems of power supply voltage interruption and inrush current caused by switching action delay and voltage mismatch in traditional switching methods. At the same time, it improves the dynamic adaptability and switching reliability of the system under complex power grid conditions through multi-parameter fusion judgment.

[0006] In a first aspect, embodiments of this application provide a control method for an energy storage system, the energy storage system including a load, an energy storage converter, an energy storage battery, and a power distribution gateway; the energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway;

[0007] A switching switch is provided between the energy storage converter and the power distribution gateway;

[0008] The method includes:

[0009] The voltage signal of the power grid is acquired, and the voltage parameters corresponding to the power grid are extracted based on the voltage signal. The voltage parameters include at least voltage amplitude, frequency and phase parameters.

[0010] If at least one of the following occurs: the voltage amplitude does not meet the preset amplitude range, the frequency does not meet the preset frequency range, or the phase parameter does not meet the preset parameter range, the target state is determined to be an off-grid state.

[0011] If the voltage amplitude meets the preset amplitude range, the frequency meets the preset frequency range, and the phase parameter meets the preset parameter range, the target state is determined to be the grid-connected state.

[0012] When the target state is an off-grid state, the voltage output of the energy storage converter is adjusted based on the voltage parameters and the target voltage parameters corresponding to the target state.

[0013] When the target state is grid-connected, the voltage output of the energy storage converter is adjusted based on the voltage parameters;

[0014] Based on the target state, the switching switch is controlled to switch states so that the energy storage converter can exchange electrical energy with the load or the power grid.

[0015] The method further includes:

[0016] The system acquires the current and power signals of the power grid, and determines a first target state of the power grid based on the voltage parameter, a second target state based on the current signal, and a third target state based on the power signal; the voltage signal, the current signal, and the power signal are pre-set with corresponding weight values.

[0017] If at least two of the first target state, the second target state, and the third target state are inconsistent, the weight values ​​corresponding to at least two different states are determined based on the weight values ​​corresponding to the voltage signal, the current signal, and the power signal, respectively, and the target state corresponding to the power grid is determined based on the weight values ​​of the at least two different states.

[0018] In one possible implementation, the target voltage parameters include at least the target voltage amplitude, the target frequency, and the target phase parameter;

[0019] The step of adjusting the voltage output of the energy storage converter based on the voltage parameters and the target voltage parameters corresponding to the target state includes:

[0020] Based on the target voltage amplitude, target frequency, and target phase parameters corresponding to the target state, the voltage output of the energy storage converter is adjusted until the output voltage meets the target voltage amplitude, target frequency, and target phase parameters.

[0021] In one possible implementation, adjusting the output voltage of the energy storage converter based on the voltage parameters includes:

[0022] Based on the voltage parameters, including voltage amplitude, frequency, and phase parameters, the voltage output of the energy storage converter is adjusted until the output voltage conforms to the voltage amplitude, frequency, and phase parameters.

[0023] In one possible implementation, controlling the switching switch to perform state switching based on the target state, so that the energy storage converter can exchange electrical energy with the load or the power grid, includes:

[0024] When the target state is off-grid, the switching switch is controlled to be switched to the load so that the energy storage converter outputs electrical energy to the load;

[0025] When the target state is grid-connected, the switching switch is controlled to switch to the power grid so that the energy storage converter can exchange electrical energy with the load or the power grid.

[0026] Secondly, embodiments of this application provide a control device for an energy storage system, the energy storage system including a load, an energy storage converter, an energy storage battery, and a power distribution gateway; the energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway;

[0027] A switching switch is provided between the energy storage converter and the power distribution gateway;

[0028] The device includes:

[0029] An extraction module is used to acquire voltage signals from the power grid and extract voltage parameters corresponding to the power grid based on the voltage signals. The voltage parameters include at least voltage amplitude, frequency, and phase parameters.

[0030] The determination module is used to determine the target state as an off-grid state when at least one of the following occurs: the voltage amplitude does not conform to a preset amplitude range, the frequency does not conform to a preset frequency range, or the phase parameter does not conform to a preset parameter range.

[0031] The determining module is further configured to determine the target state as grid-connected state when the voltage amplitude meets a preset amplitude range, the frequency meets a preset frequency range, and the phase parameter meets a preset parameter range.

[0032] The adjustment module is used to adjust the voltage output of the energy storage converter based on the voltage parameters and the target voltage parameters corresponding to the target state when the target state is an off-grid state.

[0033] The adjustment module is also used to adjust the voltage output of the energy storage converter based on the voltage parameters when the target state is grid-connected.

[0034] The switching module controls the switching switch to switch states based on the target state, so that the energy storage converter can exchange electrical energy with the load or the power grid.

[0035] The determination module is also used to acquire the current signal and power signal of the power grid, and determine the first target state of the power grid based on the voltage parameter, the second target state of the power grid based on the current signal, and the third target state based on the power signal; the voltage signal, the current signal, and the power signal are preset with corresponding weight values;

[0036] The determining module is further configured to, when at least two of the first target state, the second target state, and the third target state are inconsistent, determine the weight values ​​corresponding to at least two different states based on the weight values ​​corresponding to the voltage signal, the current signal, and the power signal, and determine the target state corresponding to the power grid based on the weight values ​​of the at least two different states.

[0037] In one possible implementation, the target voltage parameters include at least the target voltage amplitude, the target frequency, and the target phase parameter;

[0038] The adjustment module is also used to adjust the voltage output of the energy storage converter based on the target voltage amplitude, target frequency and target phase parameters corresponding to the target state, until the output voltage meets the target voltage amplitude, target frequency and target phase parameters.

[0039] In one possible implementation, the adjustment module is further configured to adjust the voltage output of the energy storage converter based on the voltage amplitude, frequency, and phase parameters included in the voltage parameters, until the output voltage conforms to the voltage amplitude, frequency, and phase parameters.

[0040] In one possible implementation, the switching module is further configured to control the switching switch to be switched to the load when the target state is an off-grid state, so that the energy storage converter outputs electrical energy to the load;

[0041] The switching module is also used to control the switching switch to be switched to the power grid when the target state is grid-connected, so that the energy storage converter can exchange electrical energy with the load or the power grid.

[0042] Thirdly, embodiments of this application provide an energy storage system, which includes a load, an energy storage converter, an energy storage battery, and a power distribution gateway;

[0043] The energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway;

[0044] The energy storage system is used in accordance with the first aspect and / or various possible implementations of the first aspect.

[0045] Fourthly, embodiments of this application provide an electronic device, including: a memory and a processor;

[0046] The memory stores computer-executed instructions;

[0047] The processor executes computer execution instructions stored in the memory, causing the processor to perform the first aspect and / or various possible implementations of the first aspect as described above.

[0048] Fifthly, embodiments of this application provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the first aspect and / or various possible implementations of the first aspect.

[0049] Sixthly, embodiments of this application provide a computer program product, including a computer program that, when executed by a processor, implements the first aspect and / or various possible implementations of the first aspect.

[0050] The control method, device, energy storage system, and storage medium for the energy storage system provided in this application extract grid voltage parameters in real time and pre-determine the target state (grid-connected or off-grid). Then, based on different target states, differentiated voltage pre-regulation strategies are adopted: when the target state is determined to be off-grid, the energy storage converter is controlled to quickly establish a stable and independent output voltage according to the preset target parameters; when the target state is determined to be grid-connected, the energy storage converter is controlled to accurately track the real-time grid parameters to achieve error-free synchronization. On this basis, the switching switch is controlled to operate. Furthermore, by introducing current and power signals as auxiliary criteria and adopting a weighted arbitration mechanism, the accuracy and reliability of grid state judgment are improved, avoiding misjudgments caused by instantaneous fluctuations in grid voltage or single sensor failures, thereby improving the robustness and safety of the entire energy storage system mode switching. It realizes a closed-loop control process of "state prediction → voltage pre-synchronization → switch switching" to effectively suppress switching impact. By actively matching the output voltage with the target mode voltage characteristics before the switch action, it eliminates the load-side voltage sag or interruption that may be caused by mechanical or logical delays in switching, and achieves seamless and smooth switching with "zero voltage sag and no inrush current", which improves the power supply continuity and equipment safety of residential energy storage under complex grid conditions. Attached Figure Description

[0051] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0052] Figure 1 Flowchart of the control method for the energy storage system provided in this application Figure 1 ;

[0053] Figure 2 Flowchart of the control method for the energy storage system provided in this application Figure 2 ;

[0054] Figure 3 Flowchart of the control method for the energy storage system provided in this application Figure 3 ;

[0055] Figure 4 A schematic diagram of the control device for the energy storage system provided in this application;

[0056] Figure 5 A schematic diagram of the structure of the electronic device provided in this application.

[0057] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0058] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0059] As the core of home energy management, residential energy storage systems need to be integrated with renewable energy sources such as solar power to achieve flexible switching between grid and off-grid modes. In the event of a grid failure, the system must quickly switch to off-grid mode to ensure power supply to critical loads. However, traditional switching methods are often accompanied by voltage interruptions and surges, making it difficult to meet the stringent requirements for power supply continuity and equipment safety in extreme environments.

[0060] Existing solutions mostly rely on mechanical or electronic switches for physical switching, which has significant drawbacks. The delay in switching action can easily cause a brief interruption in the load voltage, affecting the operation of sensitive equipment. Simultaneously, the difference in voltage characteristics between grid-connected and off-grid modes can cause abrupt changes in amplitude or phase, generating inrush currents. Furthermore, fixed decision-making logic is difficult to adapt to complex operating conditions, easily leading to erroneous switching.

[0061] This solution addresses the pain points of grid-connected and off-grid switching in residential energy storage systems. It abandons the traditional passive response method that relies on mechanical switch action and deeply integrates real-time grid status monitoring with dynamic adjustment of the energy storage converter. By acquiring grid voltage amplitude, frequency, phase and other parameters through high-frequency sampling and accurately judging grid status, it dynamically adjusts the output voltage parameters of the energy storage converter according to the target mode to achieve a perfect match with the voltage characteristics of the target mode. Combined with a waveform matching smooth switching strategy, physical switching is performed after voltage synchronization is completed to eliminate inrush current caused by potential difference. This achieves zero-interruption and shock-free seamless connection of the load-side voltage, while improving the system's dynamic adaptability to grid and load changes, ensuring the continuity and safety of power supply under complex operating conditions.

[0062] This application provides an energy storage system, which includes a load, an energy storage converter, an energy storage battery, and a power distribution gateway. The energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway. The energy storage system is used to acquire the voltage signal of the power grid and extract the voltage parameters corresponding to the power grid based on the voltage signal. Based on the voltage parameters, the target state of the power grid is determined. Based on the voltage parameters and the target state, the voltage output of the energy storage converter is adjusted. Based on the target state, a switching switch is controlled to switch the state so that the energy storage converter can exchange electrical energy with the load or the power grid.

[0063] The energy storage battery is connected to the DC side of the energy storage converter, and the AC side of the energy storage converter can be connected to the household load and the public power grid respectively through the power distribution gateway (which contains a grid-connected / off-grid switching switch), forming a physical path for bidirectional energy flow.

[0064] Understandably, this system acquires grid voltage signals in real time and accurately extracts key parameters such as voltage amplitude, frequency, and phase. Based on these parameters, it dynamically assesses the grid's target state (e.g., normal grid connection, abnormal off-grid status, or grid restoration). Before physical switching actions are executed, the system instructs the energy storage converter to actively adjust its output voltage waveform to achieve pre-synchronization and smooth matching with the voltage parameters under the target state. The core hardware architecture consists of an energy storage battery, an energy storage converter, and a distribution gateway. The energy storage battery powers the energy storage converter, and the distribution gateway connects the energy storage converter to the load and the grid. Through a dedicated control method, it acquires grid voltage signals and extracts voltage parameters, determines the grid's target state, and then dynamically adjusts the energy storage converter's output voltage based on the voltage parameters and target state. Simultaneously, it controls the distribution gateway's switching mechanism to complete state switching, ultimately achieving precise, on-demand power interaction between the energy storage converter, the load, and the grid, enabling seamless switching between grid connection and off-grid status, and ensuring continuous, stable, and safe power supply.

[0065] Figure 1 Flowchart of the control method for the energy storage system provided in this application Figure 1 .like Figure 1 As shown in this embodiment, the control method for an energy storage system includes a load, an energy storage converter, an energy storage battery, and a power distribution gateway. The energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway. A switching switch is provided between the energy storage converter and the power distribution gateway. The method includes:

[0066] S101. Obtain the voltage signal of the power grid and extract the voltage parameters corresponding to the power grid based on the voltage signal.

[0067] Among them, voltage parameters include at least voltage amplitude, frequency, and phase parameters. The voltage signal of the power grid is the raw AC voltage signal of the power grid side collected at the distribution gateway. It is the basic electrical signal reflecting the real-time operating status of the power grid and can be obtained in real time by collecting the voltage at the incoming end of the power grid through voltage and current sensors integrated in the distribution gateway. The voltage signal is the signal data obtained after preliminary processing of the collected power grid voltage signal, which can be used for subsequent parameter extraction. It contains the basic time-domain and frequency-domain characteristic information of the voltage signal. Voltage parameters are key indicators extracted from the voltage signal that characterize the core operating status of the power grid voltage. Specifically, they include the amplitude, frequency, and phase of the power grid voltage. These three types of parameters are the core basis for judging the normal operation, power outage, and voltage fluctuation status of the power grid.

[0068] Understandably, an energy storage system includes a load, an energy storage converter, an energy storage battery, and a distribution gateway. The energy storage battery is electrically connected to the energy storage converter. The energy storage converter establishes electrical connections with the load and the power grid through the distribution gateway. A switching switch is provided between the energy storage converter and the distribution gateway to realize the switching of the physical connection between the power grid and the energy storage system.

[0069] Optionally, a high-precision Hall voltage sensor or a resistor divider sampling circuit can be used to acquire the original analog signal. After sampling by a high-speed analog-to-digital converter (ADC), a fast Fourier transform (FFT), moving average filtering, or second-order generalized integrator (SOGI) algorithm can be executed using a digital signal processor (DSP) or field-programmable gate array (FPGA) to decouple the voltage amplitude, frequency, and phase parameters from the noisy signal with high precision.

[0070] Specifically, for example, a voltage sensor can be used to continuously acquire the grid voltage signal at a sampling rate of no less than 10kHz to obtain the raw voltage signal. After the acquired voltage signal is converted into a voltage signal, the amplitude, frequency, and phase parameters of the grid voltage can be accurately extracted from the voltage signal using digital signal processing algorithms such as Fourier transform. At the same time, adaptive filtering algorithms such as LMS algorithm and Kalman filter can be introduced to perform real-time noise reduction processing on the acquired voltage signal, eliminating grid noise, high-frequency harmonics, and electromagnetic interference, improving the purity of the voltage signal, and thus ensuring the accuracy of voltage parameter extraction.

[0071] By acquiring power grid voltage signals in real time and extracting voltage parameters accurately, we can provide real and reliable basic data support for determining the target state of the power grid, and realize real-time perception of the power grid's operating status.

[0072] S102. If at least one of the following occurs: voltage amplitude does not meet the preset amplitude range, frequency does not meet the preset frequency range, or phase parameter does not meet the preset parameter range, the target state is determined to be an off-grid state.

[0073] S103. If the voltage amplitude meets the preset amplitude range, the frequency meets the preset frequency range, and the phase parameter meets the preset parameter range, the target state is determined to be the grid-connected state.

[0074] The target state of the power grid can be at least a grid-connected state (the grid voltage amplitude and frequency are within the allowable range of national standards, such as 220V±10%, 50Hz±0.5Hz), an off-grid state (a power outage, severe voltage drop / sudden rise, frequency exceeding limits, or islanding effect is detected), and a grid-connection preparation state (the grid parameters have recovered from abnormal to normal range and have remained stable for a certain period of time). In a preferred embodiment, the target state can be further subdivided into "planned off-grid" and "fault-induced off-grid" so that the system can adopt different response strategies, which will not be elaborated here.

[0075] Understandably, preset parameter ranges that conform to the grid operation standards are set for the grid voltage amplitude, frequency, and phase. The extracted voltage parameters are compared with the corresponding preset ranges one by one. If at least one of the following situations occurs: the voltage amplitude does not conform to the preset amplitude range, the frequency does not conform to the preset frequency range, or the phase parameter does not conform to the preset phase range, the grid target state is directly determined to be off-grid. If the voltage amplitude, frequency, and phase parameters all conform to their respective preset parameter ranges, the grid target state is determined to be grid-connected.

[0076] Optionally, this solution can also be implemented by pre-setting a state machine algorithm in the controller. The system inputs the real-time collected voltage parameters into the state machine. If the parameters exceed the set threshold for N consecutive sampling periods (N is a configurable integer used for anti-jitter), the state machine jumps to the "off-grid state"; if the parameters return to the threshold range within the set time and phase locking is successful, it jumps to the "grid-connected preparation state" or "grid-connected state". In addition, zero-crossing detection technology and the output state of the phase-locked loop (PLL) can be combined to jointly determine the state, thereby improving the robustness of state recognition.

[0077] S104. When the target state is off-grid, adjust the output voltage of the energy storage converter based on the voltage parameters and the target voltage parameters corresponding to the target state.

[0078] The target voltage parameters include at least the target voltage amplitude, target frequency, and target phase parameters.

[0079] S105. When the target state is grid-connected, adjust the output voltage of the energy storage converter based on the voltage parameters.

[0080] The voltage output by the energy storage converter is the AC voltage signal that the converter outputs to the load / grid. Its amplitude, frequency, and phase can be dynamically adjusted by the converter's internal control module.

[0081] Specifically, when the target state is off-grid, the energy storage converter can switch to voltage control mode (V / f mode) and autonomously construct the output voltage waveform based on preset standard grid parameters (such as 220V / 50Hz) to simulate grid characteristics and maintain load power supply. For example, based on the grid's rated operating standard, preset target voltage parameters corresponding to the off-grid state (including at least target voltage amplitude, target frequency, and target phase parameters, such as the mains standard 220V / 50Hz and corresponding phase) are used. Combined with the extracted grid voltage parameters, the energy storage converter is driven by closed-loop control algorithms such as PID control to gradually adjust its output voltage amplitude, frequency, and phase until the output voltage fully meets the preset target voltage parameters, thus simulating the grid voltage characteristics in off-grid mode.

[0082] When the target state is grid-connected, the energy storage converter can switch to synchronous control mode, collect grid voltage parameters from the point of common coupling (PCC) in real time, and dynamically adjust the amplitude, frequency, and phase of its output voltage through a phase-locked loop (PLL) algorithm to keep it strictly synchronized with the grid voltage until the grid connection conditions are met. That is, the extracted real-time grid voltage amplitude, frequency, and phase parameters are directly used as the matching standard, and the grid voltage parameters are tracked in real time through PLL technology. At the same time, the output voltage of the energy storage converter is dynamically adjusted based on the closed-loop control algorithm until its amplitude, frequency, and phase are completely consistent with the real-time grid voltage parameters, achieving seamless synchronization with the grid voltage.

[0083] For example, the specific adjustment steps in off-grid mode can include preset input parameters, including: reference voltage. Reference frequency And determine the feedback parameters, that is, the real-time voltage at the actual output terminal of the converter. By calculating the error By adjusting the modulation ratio of the SPWM modulation wave through a PI / PID controller, closed-loop voltage regulation control is achieved in off-grid conditions, regardless of the load. Stable at nearby.

[0084] In grid-connected mode, the real-time voltage on the grid side can be input as a parameter. This can include amplitude. ,frequency Phase For example, using a phase-locked loop (PLL) to extract... The instantaneous phase and frequency; the internal reference voltage command of the converter. Updated to The above enables feedforward synchronous tracking in grid-connected mode, allowing the converter output voltage to dynamically track changes in the grid voltage and ensuring the difference between the two is minimized. This eliminates the inrush current the instant the switch is closed.

[0085] Understandably, in off-grid mode, negative feedback voltage regulation is performed based on preset standard parameters to construct an independent power grid; in grid-connected mode, feedforward synchronous regulation is performed based on real-time sampled grid parameters to achieve error-free tracking. Both modes address the technical challenges of off-grid power supply stability and grid-connected impact suppression respectively through state machine switching control strategies.

[0086] In one optional embodiment, multivariate collaborative control algorithms such as model predictive control (MPC) or fuzzy control can also be used to treat voltage amplitude, frequency, and phase as collaborative adjustment variables, and calculate the adjustment amount of each parameter at the same time. Priority is given to optimizing parameters such as phase synchronization that have the greatest impact on the load, so as to achieve comprehensive and rapid matching between the output voltage of the energy storage converter and the target state.

[0087] In the specific adjustment process, the control module of the energy storage converter can first calculate the voltage adjustment value based on the voltage parameters and target state, generate control signals such as PWM and input them to the converter inverter. By adjusting the turn-on and turn-off sequence of the inverter's power electronic switches (such as IGBTs), the output voltage parameters can be adjusted step by step, avoiding voltage fluctuations caused by excessive adjustment in a single step.

[0088] Preferably, when the target state is determined to be "normal grid connection" or "restoration to grid connection preparation state", the control system can activate the grid connection pre-synchronization logic, using phase-locked loop (PLL) technology to track the phase and frequency of the grid voltage parameters. Through a closed-loop regulation algorithm (such as a proportional-integral resonant controller PIR), the output voltage of the energy storage converter is forced to maintain a high degree of consistency with the grid voltage parameters in amplitude, frequency, and phase (i.e., the error approaches zero), eliminating the potential difference between the two. When the target state is determined to be "abnormal off-grid", the control system can switch to off-grid voltage regulation logic (V / f control mode), constructing virtual synchronous machine characteristics based on preset rated voltage parameters (such as 220V / 50Hz), quickly establishing and stabilizing the independent voltage source required by the load, to ensure that there is no sudden change in the load-side voltage at the moment of grid disconnection.

[0089] S106. Based on the target state control switching switch, the state is switched so that the energy storage converter can exchange electrical energy with the load or the power grid.

[0090] Among them, the switching switch is a hardware switching device set between the energy storage converter and the power distribution gateway. It can be a relay, solid-state switch, or other on-grid and off-grid switching switch. It is the execution carrier for realizing the physical connection switching between the energy storage system and the power grid and load. Power interaction refers to the directional power transmission between the energy storage converter and the load and the power grid according to the target state. This includes the working mode of supplying power to the load separately when off-grid and exchanging power bidirectionally with the power grid and supplying power to the load when connected to the grid.

[0091] Understandably, if the target state is off-grid, the control switch is switched to the load side, disconnecting the physical connection between the energy storage converter and the grid, establishing an independent power supply path between the energy storage converter and the load, so that the energy storage converter can convert the electrical energy of the energy storage battery and continuously output stable electrical energy to the critical loads of the household, thus realizing independent power supply in off-grid mode.

[0092] If the target state is grid-connected, the control switch is switched to the grid side to establish a connection path between the energy storage converter and the grid and load, so that the energy storage converter can perform bidirectional power interaction with the grid (sending power to the grid when there is surplus photovoltaic power generation, and drawing power from the grid when there is insufficient power supply), while providing continuous power supply to the load, realizing coordinated energy supply in grid-connected mode.

[0093] Optionally, when performing physical switching, a timing control logic of "on first, off later" can be adopted to ensure that at least one power supply path is in a conducting state during the switching process, completely eliminating the load-side voltage interruption caused by mechanical delay of the switch; at the same time, the switching action delay time can be dynamically adjusted according to the voltage matching degree. The higher the matching degree, the shorter the action time, thus improving the switching efficiency.

[0094] In one optional embodiment, before triggering the switching action, the matching degree between the output voltage of the energy storage converter and the target state voltage characteristics can be detected (the core indicators of comprehensive amplitude error, frequency error, and phase error). When the matching degree reaches a preset threshold, a switching enable signal (valid state) is generated. Subsequent switching operations are only performed when the enable signal is valid, which can avoid erroneous switching when voltage matching is not completed.

[0095] The control method for the energy storage system provided in this application extracts grid voltage parameters in real time and pre-determines the target state (grid-connected or off-grid). Then, it adopts differentiated voltage pre-regulation strategies according to different target states: when the target state is determined to be off-grid, the energy storage converter is controlled to quickly establish a stable and independent output voltage according to the preset target parameters; when the target state is determined to be grid-connected, the energy storage converter is controlled to accurately track the real-time grid parameters to achieve error-free synchronization. On this basis, the switching switch is controlled to operate. Furthermore, by introducing current and power signals as auxiliary criteria and adopting a weighted arbitration mechanism, the accuracy and reliability of grid state judgment are improved, avoiding misjudgments caused by instantaneous fluctuations in grid voltage or single sensor failures, thereby improving the robustness and safety of the entire energy storage system mode switching. It realizes a closed-loop control process of "state prediction → voltage pre-synchronization → switch switching" to effectively suppress switching impact. By actively matching the output voltage with the target mode voltage characteristics before the switch action, it eliminates the load-side voltage sag or interruption that may be caused by mechanical or logical delays in switching, and achieves seamless and smooth switching with "zero voltage sag and no inrush current", which improves the power supply continuity and equipment safety of residential energy storage under complex grid conditions.

[0096] Figure 2 A flowchart illustrating the control method for the energy storage system provided in this application embodiment. Figure 2 .like Figure 2 As shown, this embodiment is... Figure 1 Based on the embodiments, the control method of the energy storage system is described in detail, and the method includes:

[0097] S201. Obtain the voltage signal of the power grid and extract the corresponding voltage parameters of the power grid based on the voltage signal.

[0098] The voltage parameters include at least the voltage amplitude, frequency, and phase parameters.

[0099] Step S201 is similar to step S101 described above, and will not be repeated here.

[0100] S202. If at least one of the following occurs: voltage amplitude does not meet the preset amplitude range, frequency does not meet the preset frequency range, or phase parameter does not meet the preset parameter range, the target state is determined to be an off-grid state.

[0101] The preset amplitude range, frequency range, and phase parameter range can be threshold values ​​of normal grid operation parameters pre-set according to civil power supply standards and the operational requirements of household energy storage systems. These threshold values ​​can be adjusted to adapt to actual application scenarios (such as different regional grid power standards and household load power supply needs). Off-grid status is an independent power supply mode that the energy storage system needs to switch to when the grid cannot supply power normally due to faults such as power outages, voltage drops / surges, frequency shifts, and phase changes. At this time, the energy storage system will disconnect from the grid, and the energy storage battery will continuously supply power to the household's critical loads through the energy storage converter.

[0102] Understandably, based on the single-parameter anomaly determination, the real-time voltage amplitude, frequency, and phase parameters of the power grid can be compared with the preset corresponding parameter ranges one by one. If any one of the three parameters exceeds the preset range, the power grid is determined to be in a fault condition, and the target state of the power grid is directly determined to be the off-grid state.

[0103] Optionally, in the actual judgment process, in order to avoid misjudgment caused by instantaneous fluctuations in grid voltage, auxiliary logic for judging the duration of abnormal parameters can be added. That is, when a parameter is detected to exceed the preset range, it is not immediately determined to be disconnected from the grid. Instead, the parameter is continuously collected and the duration of the abnormal state is monitored. When the duration of the abnormal state reaches the preset duration (such as tens of milliseconds), the target state is officially determined to be disconnected from the grid. This effectively avoids unnecessary disconnection switching caused by instantaneous disturbances in the grid and improves the robustness of the judgment logic.

[0104] S203. If the voltage amplitude meets the preset amplitude range, the frequency meets the preset frequency range, and the phase parameter meets the preset parameter range, the target state is determined to be the grid-connected state.

[0105] Among them, the grid-connected state is the operating mode in which the energy storage system is connected to the public power grid when the power grid is in normal power supply condition. At this time, the energy storage system can have bidirectional power interaction with the power grid, supply power to household loads, and also absorb renewable energy generation such as photovoltaic power generation.

[0106] Understandably, the extracted real-time voltage amplitude, frequency, and phase parameters of the power grid are compared with the preset corresponding parameter ranges one by one. Only when the voltage amplitude, frequency, and phase parameters all meet their respective preset compliance ranges is the power grid determined to be in normal operating condition, and thus the target state of the power grid is determined to be the grid-connected state.

[0107] Optionally, in actual judgment, to further improve the reliability of grid connection judgment, auxiliary logic for verifying the duration of parameter compliance can also be added. That is, when it is detected that all three parameters meet the preset range, grid connection is not immediately determined. Instead, the duration of parameter compliance status is continuously collected and monitored. When the compliance status lasts for a preset duration (such as tens of milliseconds), the target status is officially determined as the grid connection status. This effectively filters out false compliance signals caused by the instantaneous recovery of grid parameters and avoids erroneous grid connection operations of the energy storage system when the grid has not been stably restored.

[0108] S204. When the target state is off-grid, adjust the output voltage of the energy storage converter based on the target voltage amplitude, target frequency and target phase parameters corresponding to the target state until the output voltage meets the target voltage amplitude, target frequency and target phase parameters.

[0109] The target voltage parameters include at least the target voltage amplitude, target frequency, and target phase parameters. The target voltage amplitude can be set to the effective value of the rated voltage required by the load (e.g., single-phase 220V or three-phase 380V). This value can be fixed or dynamically fine-tuned according to the reactive power demand of the load to maintain bus voltage stability. The target frequency can be set to the standard power frequency (e.g., 50Hz or 60Hz). In scenarios with black start or microgrid master-slave control functions, this frequency can be fine-tuned by droop control according to the system's active power balance. For the target phase parameter, since there is no external grid phase reference in the off-grid state, the system can initialize the phase (usually set to 0 or maintain phase continuity at the moment of switching) and perform integral calculations based on the target frequency to generate a continuously changing phase reference value, thereby constructing a phase reference that grows linearly with time.

[0110] Understandably, the target voltage amplitude, target frequency, and target phase parameters corresponding to the off-grid state are retrieved and compared with the extracted real-time grid voltage parameters to calculate the adjustment values ​​for each parameter of the energy storage converter's output voltage. Subsequently, a control signal is generated through closed-loop control algorithms such as PID control and input to the inverter control module of the energy storage converter to adjust the on and off timing of the power electronic switches (such as IGBTs) in the inverter, gradually adjusting the amplitude, frequency, and phase of the converter's output voltage. During the adjustment process, the output voltage parameters are collected in real time through the voltage feedback circuit inside the converter, continuously compared with the target voltage parameters, and iteratively corrected until the amplitude, frequency, and phase of the energy storage converter's output voltage completely match the preset off-grid target voltage parameters, achieving precise matching of the voltage waveform.

[0111] Preferably, multivariate collaborative control algorithms such as model predictive control (MPC) can be introduced, using the target voltage amplitude, frequency, and phase as collaborative adjustment variables. The adjustment amount of each parameter is calculated and adjusted synchronously, prioritizing the optimization of the phase parameter that has the greatest impact on the stability of the load power supply, avoiding voltage fluctuations caused by the successive adjustment of a single parameter, and improving regulation efficiency and matching accuracy.

[0112] Meanwhile, to avoid sudden changes in load voltage during the switch from grid-connected to off-grid, this step can also adopt a phase-maintaining strategy when initializing the target phase parameters. That is, the instantaneous phase of the grid voltage at the switching moment is used as the initial value of the off-grid target phase, and then the system runs freely at the target frequency to ensure the continuity of the voltage waveform before and after the switch, and to prevent the inductive load from generating overvoltage or overcurrent due to voltage phase jumps.

[0113] Using the off-grid target voltage amplitude, target frequency, and target phase parameters as the sole adjustment benchmark, the three core parameters of the output voltage are adjusted one by one through the dynamic adjustment system of the energy storage converter until all parameters fully meet the target values.

[0114] Specifically, the control module of the energy storage converter retrieves the target voltage amplitude, target frequency, and target phase parameters corresponding to the off-grid state as the target values ​​for output voltage adjustment. Subsequently, closed-loop control algorithms such as PID control generate corresponding adjustment commands to drive the inverter to adjust the on and off timing of the power electronic switches. First, the output voltage amplitude is adjusted to gradually approach and match the target voltage amplitude. Then, the frequency and phase are precisely adjusted in sequence, or the three parameters are simultaneously adjusted through a multi-variable collaborative control algorithm. During the adjustment process, the voltage feedback circuit inside the converter continuously collects the real-time parameters of the output voltage and compares them with the target parameters in real time. If there is a deviation, a correction command is immediately generated through the control algorithm for iterative adjustment until the amplitude, frequency, and phase of the energy storage converter's output voltage all accurately match the corresponding target voltage parameters, thus completing the voltage matching adjustment in the off-grid state.

[0115] Optionally, this step can be embedded in the control firmware of a DSP or FPGA, employing a dual closed-loop control structure (outer loop voltage / frequency control, inner loop current control). The target voltage parameter serves as the setpoint for the outer loop, and the actual voltage parameter serves as the feedback value. The final PWM duty cycle is calculated using algorithms such as PID, repetitive control, or model predictive control, driving the inverter bridge arm and thus physically changing the output voltage waveform until it completely coincides with the target parameter.

[0116] S205. When the target state is grid-connected, adjust the output voltage of the energy storage converter based on the voltage parameters, including voltage amplitude, frequency and phase parameters, until the output voltage meets the voltage amplitude, frequency and phase parameters.

[0117] The process involves inputting the extracted real-time grid voltage amplitude, frequency, and phase parameters into the phase-locked loop (PLL) control module of the energy storage converter. The PLL module then tracks and locks the grid voltage parameters in real time, accurately capturing dynamic changes in the grid voltage. Subsequently, using the real-time grid voltage parameters as the adjustment target, a PID closed-loop control algorithm generates adjustment commands to drive the inverter of the energy storage converter to adjust the on and off timing of power electronic switches (such as IGBTs), dynamically adjusting the amplitude, frequency, and phase of the output voltage. During the adjustment process, the voltage feedback circuit inside the converter continuously collects the real-time output voltage parameters and compares them with the real-time grid voltage parameters at the millisecond level. If an amplitude deviation, frequency shift, or phase difference is detected, a correction signal is immediately generated through the closed-loop control algorithm, iteratively adjusting the output voltage parameters until the amplitude, frequency, and phase of the energy storage converter's output voltage are completely synchronized with the real-time grid voltage parameters without deviation, completing the voltage matching adjustment under grid-connected conditions.

[0118] Optionally, in actual adjustment, a voltage synchronization accuracy check can be added, with a preset voltage synchronization accuracy threshold (such as amplitude deviation less than 1V, frequency deviation less than 0.1Hz, and phase difference less than 1°). Voltage regulation is determined to be completed only when the deviation between the output voltage of the energy storage converter and the real-time voltage parameters of the grid is less than this threshold, further ensuring the accuracy of grid-connected voltage synchronization.

[0119] Understandably, after voltage synchronization regulation is completed, the output voltage of the energy storage converter has no characteristic difference from the grid voltage, which lays a shock-free execution foundation for the subsequent physical operation of switching to the grid side, realizes seamless grid connection switching, and avoids load-side voltage fluctuations or interruptions during the switching process.

[0120] By combining real-time grid parameters with closed-loop iterative calibration, and using the real-time grid voltage amplitude, frequency, and phase as adjustment targets, the energy storage converter's dynamic adjustment system synchronously or sequentially adjusts the three core parameters of the output voltage until all parameters are fully matched with the real-time grid parameters.

[0121] Specifically, the control module of the energy storage converter retrieves the real-time voltage amplitude, frequency, and phase parameters of the power grid as the basis for precise adjustment of the output voltage. Subsequently, phase-locked loop (PLL) technology is used to achieve real-time locking and frequency tracking of the power grid voltage phase. At the same time, combined with closed-loop control algorithms such as PID, multi-dimensional adjustment commands are generated to drive the inverter to adjust the on / off timing and duty cycle of power electronic switches such as IGBTs, synchronously adjusting the amplitude, frequency, and phase of the energy storage converter's output voltage, or performing precise calibration step by step according to parameter matching priorities. During the adjustment process, the voltage feedback circuit inside the converter continuously collects the real-time parameters of the output voltage in a high-frequency sampling manner and performs millisecond-level precise comparison with the real-time voltage parameters of the power grid. If any deviation of any parameter is detected, a correction command is immediately generated through the closed-loop control algorithm to iteratively adjust the output parameters until the amplitude, frequency, and phase of the energy storage converter's output voltage completely match the corresponding real-time voltage parameters of the power grid, completing the precise voltage matching adjustment under grid-connected conditions.

[0122] S206. When the target state is off-grid, control the switching switch to be switched to the load so that the energy storage converter outputs electrical energy to the load.

[0123] Among them, the switching switch can be a hardware switching device for grid connection and off-grid operation set between the energy storage converter and the distribution gateway. It can be a power switch with on and off control functions, such as a relay or solid-state switch, and is the execution carrier for realizing the physical switching of the power supply path. The load can be, for example, a critical household electrical appliance, including refrigerators, medical equipment, communication equipment and other equipment with high requirements for power supply continuity. It is the power supply target of the energy storage system in off-grid mode. The energy storage converter outputs electrical energy to the load, which means that the energy storage converter converts the DC power stored in the energy storage battery into AC power that meets the off-grid target voltage parameters, and continuously delivers stable electrical energy to the load through the switched power supply path.

[0124] Specifically, the voltage matching results are pre-verified to confirm that the amplitude, frequency, and phase of the energy storage converter's output voltage fully meet the off-grid target voltage parameters, and a valid switching enable signal is generated. After the verification is passed, the energy storage system's control module sends an action command to the switching switch to disconnect the physical connection with the grid side, switch on, and connect the load-side path. During the switching operation, a first-on, then-off timing logic is adopted, that is, the power supply path between the energy storage converter and the load is first connected, and then the connection with the grid is disconnected, ensuring that the load side always has a stable power input during the switching process, completely eliminating voltage interruptions caused by mechanical delays in the switch. At the same time, after the switch is activated, the path continuity status is continuously monitored. After confirming that the switch is in place, an off-grid switching completion signal is fed back to the energy storage system, and the system enters the off-grid stable power supply mode.

[0125] Optionally, switching failure detection can also be performed. If no switch position feedback signal or load-side voltage establishment is detected within a specified time (e.g., 100ms) after the command is issued, the system determines that the switching has failed, immediately blocks the converter pulse and alarms.

[0126] Preferably, if the load surge current exceeds the converter's capacity (such as motor starting current) at the instant the switch is applied to the load, the control system can immediately activate the current limiting algorithm or cut off non-critical loads in stages to prevent the converter from tripping due to overcurrent.

[0127] S207. When the target state is grid-connected, control the switching switch to be switched to the grid so that the energy storage converter can exchange electrical energy with the load or the grid.

[0128] Among them, power exchange refers to the bidirectional power transmission function of the energy storage converter under grid-connected mode. Specifically, it can transmit the surplus power generated by renewable energy sources such as photovoltaics or the power of energy storage batteries to the grid, and can also obtain power from the grid during peak household electricity consumption and when photovoltaic power generation is insufficient, while always providing a stable power supply to household loads.

[0129] Specifically, a precise pre-verification of the voltage synchronization result is performed to confirm that the amplitude, frequency, and phase of the output voltage of the energy storage converter are completely consistent with the real-time parameters of the power grid, and the deviation is lower than the preset synchronization accuracy threshold, generating a valid switching enable signal. After the verification is passed, the control module of the energy storage system sends an action command to the switching switch to control the switching switch to connect the physical connection with the grid side and maintain the connection with the load side. During the switching action, a first-on, then-off timing logic is adopted (if it was previously in an off-grid state, the grid side path is connected first, and then the off-grid path is closed after confirming that the load power supply is uninterrupted), ensuring that there is always a stable power input at the load end during the switching process, completely eliminating voltage interruptions caused by mechanical or logical delays in the switch. After the switching action is completed, the conduction status and voltage synchronization status of the grid side and load side paths are continuously monitored. After confirming that the switch is in place and the system is running stably, a grid-connected switching completion signal is fed back to the energy storage system, and the system enters the grid-connected stable operation mode.

[0130] Optionally, after the switch is closed, the system's synchronous adjustment logic can switch to implicit operation. Since it is physically rigidly connected to the power grid, the converter's output voltage is clamped by the grid. The control system continues to sample the grid voltage parameters in real time (as feedforward) and dynamically adjusts the converter's modulation waveform to ensure that the output current waveform is pure, harmonic-free, and strictly follows changes in grid frequency and phase. If grid fluctuations occur, the converter automatically adjusts its output power to maintain system stability, or executes a tripping and disconnection procedure when the protection threshold is exceeded.

[0131] The energy storage system control method provided in this application collects grid voltage, current, and power signals and uses a weighted fusion algorithm to accurately determine the target state of grid connection or off-grid operation. If the states are inconsistent, the final state is confirmed based on preset weighted arbitration. When it is confirmed as off-grid, the converter is controlled to quickly build up voltage and switch to supply power to the load; when it is confirmed as grid connection, a synchronization adjustment is performed and the switch is switched to the grid to achieve bidirectional power exchange. Through multi-source signal weighted fusion and dynamic arbitration mechanism, the risk of misjudgment based on a single criterion is effectively reduced, and the sensitivity of islanding detection and the accuracy of state identification under complex operating conditions and the reliability of system operation are significantly improved.

[0132] Figure 3 A flowchart illustrating the control method for the energy storage system provided in this application embodiment. Figure 3 .like Figure 3 As shown, this embodiment is... Figure 1 Based on the embodiments, the steps for determining the target state of the power grid based on voltage parameters are described in detail. The method further includes:

[0133] S301. Acquire the current signal and power signal of the power grid, and determine the first target state of the power grid based on the voltage parameter, the second target state of the power grid based on the current signal, and the third target state based on the power signal.

[0134] The voltage, current, and power signals are pre-set with corresponding weight values. The current and power signals of the power grid are real-time operating electrical signals of the power grid collected from the same source as the voltage signal. The current signal reflects the operating characteristics of the power grid, such as the current amplitude and frequency. The power signal is calculated from the voltage and current signals and reflects the active and reactive power output status of the power grid. Together with the voltage signal, they constitute a multi-source basis for determining the power grid status. The pre-set weight values ​​of the voltage, current, and power signals can be preset according to the degree of importance of each signal in determining the power grid status. The voltage signal has the highest weight, while the current and power signals serve as auxiliary basis for determination. The weight values ​​can be adjusted according to the operating conditions of the residential energy storage system and the power grid environment.

[0135] Specifically, the current sensor and power detection module in the distribution gateway synchronously and at high frequency acquire real-time current and power signals from the incoming power grid, achieving synchronous acquisition of multi-source operating signals. The acquired current and power signals are then filtered, denoised, and parameter extracted to obtain core parameters such as current amplitude, frequency, active power, and reactive power. Corresponding judgment weights are pre-configured for the voltage, current, and power signals. Based on the voltage, current, and power parameters, and according to their respective preset normal operating threshold ranges, the power grid state judgment logic is executed independently, sequentially yielding the first, second, and third target states of the power grid. These three state judgment processes are independent and do not interfere with each other, providing a foundation for subsequent multi-source state fusion judgment.

[0136] Understandably, the first target state is based on voltage parameters and can detect whether the voltage exceeds the limit (overvoltage / undervoltage), whether the frequency drifts (overfrequency / underfrequency), and whether the phase changes abruptly.

[0137] The second target state is based on the current signal and can detect the current direction, current change rate and current waveform characteristics. If the current is detected to be reversed and the amplitude is stable, it may indicate "power supply to the grid"; if the current suddenly disappears but the voltage exists, it may indicate "islanding operation"; if the current waveform is drastically distorted, it may indicate "grid disturbance".

[0138] The third target state is based on power signals and can detect the balance of active and reactive power, power factor changes, and power oscillations.

[0139] Optionally, in the actual acquisition and judgment process, a high-frequency sampling rate, filtering algorithm and abnormal duration verification logic consistent with the voltage signal can be used to ensure the consistency between the acquisition accuracy of the current and power signals and the judgment logic, and to avoid judgment deviations caused by different signal processing standards.

[0140] S302. If at least two of the first target state, the second target state, and the third target state are inconsistent, determine the weight values ​​corresponding to at least two different states based on the weight values ​​corresponding to the voltage signal, the current signal, and the power signal, and determine the target state corresponding to the power grid based on the weight values ​​of at least two different states.

[0141] The first, second, and third target states are the grid state results obtained independently based on voltage, current, and power signals, respectively, and each includes both grid-connected and off-grid states. Inconsistency between at least two states refers to a discrepancy between grid-connected and off-grid states in the three independent judgment results (e.g., the first is off-grid, the second and third are grid-connected, or the first and second are off-grid, the third is grid-connected, etc.), which is a prerequisite for triggering the weighted fusion judgment in this step. The weight values ​​corresponding to voltage, current, and power signals are pre-configured weight coefficients, with voltage signal weight being the highest and current and power signals being auxiliary weights. The sum of the weight values ​​of the three types of signals is 1, and can be adjusted according to the grid operating environment and energy storage system operating conditions. The weight values ​​corresponding to different states refer to the comprehensive weight obtained by summing the weight values ​​of each signal with a judgment result of that state, treating both grid-connected and off-grid states as aggregation objects.

[0142] Specifically, a consistency check is performed on the first, second, and third target states. If at least two of the determination results are inconsistent, a weight fusion determination process is triggered. Subsequently, weights are aggregated according to the grid-connected and off-grid states. The weight values ​​corresponding to all signals with the determination result of grid-connected state are summed to obtain the comprehensive weight value of the grid-connected state. Similarly, the weight values ​​corresponding to all signals with the determination result of off-grid state are summed to obtain the comprehensive weight value of the off-grid state. Finally, the comprehensive weight values ​​of the grid-connected and off-grid states are compared, and the state with the higher comprehensive weight value is determined as the final target state of the power grid. In the extreme case where the comprehensive weight values ​​of the two states are equal, the first target state determined by the voltage signal is used as the final target state of the power grid by default to ensure the uniqueness of the determination result.

[0143] In some optional embodiments, auxiliary logic for verifying the weighted fusion results can be added to compare the final target state obtained from the fusion determination with the real-time operating parameters of the power grid, confirming that the state determination result matches the actual operating conditions of the power grid, and further improving the accuracy of the determination.

[0144] The control method for the energy storage system provided in this application collects grid voltage, current, and power signals to independently determine the first, second, and third target states. When inconsistencies arise among the three, a weighted arbitration mechanism is activated. Based on preset weights, a comprehensive confidence score for each candidate state is calculated, and the state with the highest score is selected as the final grid target state. Through the redundant design of multi-source signal fusion and weighted determination, the accuracy and fault tolerance of grid state determination are significantly improved, effectively avoiding misjudgment problems caused by a single signal anomaly.

[0145] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0146] Based on the same inventive concept, this application also provides a control device for an energy storage system to implement the control method of the energy storage system described above. The solution provided by this control device is similar to the solution described in the control method of the energy storage system. Therefore, the specific limitations in one or more device embodiments provided below can be found in the limitations of the control method of the energy storage system described above, and will not be repeated here.

[0147] In one embodiment, such as Figure 4 As shown, a control device 400 for an energy storage system is provided. The energy storage system includes a load, an energy storage converter, an energy storage battery, and a power distribution gateway. The energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway. A switching switch is provided between the energy storage converter and the power distribution gateway. The control device 400 for the energy storage system includes:

[0148] The extraction module 401 is used to acquire the voltage signal of the power grid and extract the voltage parameters corresponding to the power grid based on the voltage signal. The voltage parameters include at least voltage amplitude, frequency and phase parameters.

[0149] The determination module 402 is used to determine the target state as an off-grid state when at least one of the following occurs: the voltage amplitude does not meet the preset amplitude range, the frequency does not meet the preset frequency range, or the phase parameter does not meet the preset parameter range.

[0150] The determining module 402 is also used to determine the target state as grid-connected state when the voltage amplitude meets the preset amplitude range, the frequency meets the preset frequency range, and the phase parameter meets the preset parameter range.

[0151] The adjustment module 403 is used to adjust the output voltage of the energy storage converter based on the voltage parameters and the target voltage parameters corresponding to the target state when the target state is off-grid.

[0152] The adjustment module 403 is also used to adjust the output voltage of the energy storage converter based on voltage parameters when the target state is grid-connected.

[0153] The switching module 404 controls the switching switch to perform state switching based on the target state, so that the energy storage converter can exchange electrical energy with the load or the power grid.

[0154] The determining module 402 is also used to acquire the current signal and power signal of the power grid, and determine the first target state of the power grid based on the voltage parameter, the second target state of the power grid based on the current signal, and the third target state based on the power signal; the voltage signal, current signal and power signal are preset with corresponding weight values;

[0155] The determining module 402 is further configured to, when at least two of the first target state, the second target state, and the third target state are inconsistent, determine the weight values ​​corresponding to at least two different states based on the weight values ​​corresponding to the voltage signal, the current signal, and the power signal, and determine the target state corresponding to the power grid based on the weight values ​​of the at least two different states.

[0156] In one possible implementation, the target voltage parameters include at least the target voltage amplitude, the target frequency, and the target phase parameter;

[0157] The adjustment module 403 is also used to adjust the output voltage of the energy storage converter based on the target voltage amplitude, target frequency and target phase parameters corresponding to the target state, until the output voltage meets the target voltage amplitude, target frequency and target phase parameters.

[0158] In one possible implementation, the adjustment module 403 is further configured to adjust the output voltage of the energy storage converter based on the voltage parameters, including voltage amplitude, frequency, and phase parameters, until the output voltage conforms to the voltage amplitude, frequency, and phase parameters.

[0159] In one possible implementation, the switching module 404 is also used to control the switching switch to be switched to the load when the target state is an off-grid state, so that the energy storage converter outputs electrical energy to the load.

[0160] The switching module 404 is also used to control the switching switch to be switched to the grid when the target state is grid-connected, so that the energy storage converter can exchange electrical energy with the load or the grid.

[0161] Each module in the above-mentioned device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0162] Figure 5 A schematic diagram of the structure of the electronic device provided in this application. Figure 5 As shown, the electronic device 500 provided in this embodiment includes at least one processor 501 and a memory 502. Optionally, the electronic device 500 further includes a communication component 503. The processor 501, memory 502, and communication component 503 are connected via a bus 504.

[0163] In a specific implementation, at least one processor 501 executes computer execution instructions stored in memory 502, causing at least one processor 501 to perform the above-described method.

[0164] The specific implementation process of processor 501 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0165] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0166] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0167] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0168] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0169] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0170] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0171] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0172] The division of units is merely a logical functional division; 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 indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0173] 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.

[0174] In addition, the functional units in the various embodiments of the present invention 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.

[0175] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium 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 invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0176] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0177] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A control method for an energy storage system, characterized in that, The energy storage system includes a load, an energy storage converter, an energy storage battery, and a power distribution gateway; the energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway; A switching switch is provided between the energy storage converter and the power distribution gateway; The method includes: The voltage signal of the power grid is acquired, and the voltage parameters corresponding to the power grid are extracted based on the voltage signal. The voltage parameters include at least voltage amplitude, frequency and phase parameters. Based on the voltage parameters, a first target state corresponding to the power grid is determined: if at least one of the following occurs, the voltage amplitude does not meet the preset amplitude range, the frequency does not meet the preset frequency range, or the phase parameter does not meet the preset parameter range, the first target state is determined to be an off-grid state; if the voltage amplitude meets the preset amplitude range, the frequency meets the preset frequency range, and the phase parameter meets the preset parameter range, the first target state is determined to be a grid-connected state. The current signal and power signal of the power grid are acquired, and the second target state and the third target state of the power grid are determined based on the current signal and the power signal, respectively; the voltage signal, the current signal and the power signal are preset with corresponding weight values; If the first target state, the second target state, and the third target state are consistent, then the consistent state is determined as the target state corresponding to the power grid; if at least two of the first target state, the second target state, and the third target state are inconsistent, then: the weight values ​​corresponding to each signal determined to be in the grid-connected state are summed to obtain the comprehensive weight value of the grid-connected state; the weight values ​​corresponding to each signal determined to be in the off-grid state are summed to obtain the comprehensive weight value of the off-grid state; the state with the higher comprehensive weight value is determined as the target state corresponding to the power grid. When the target state is an off-grid state, the voltage output of the energy storage converter is adjusted using preset standard grid parameters as the target voltage parameters until the output voltage meets the target voltage parameters; wherein, the preset standard grid parameters include target voltage amplitude, target frequency and target phase parameters; When the target state is grid-connected, the voltage output of the energy storage converter is adjusted based on the voltage amplitude, frequency and phase parameters included in the voltage parameters, until the output voltage meets the voltage amplitude, frequency and phase parameters; After the voltage adjustment of the energy storage converter is completed, the switching switch is controlled to switch states based on the target state, so that the energy storage converter can exchange electrical energy with the load or the power grid.

2. The method according to claim 1, characterized in that, The step of controlling the switching switch to perform state switching based on the target state, so as to enable the energy storage converter to exchange electrical energy with the load or the power grid, includes: When the target state is off-grid, the switching switch is controlled to be switched to the load so that the energy storage converter outputs electrical energy to the load; When the target state is grid-connected, the switching switch is controlled to switch to the power grid so that the energy storage converter can exchange electrical energy with the load or the power grid.

3. A control device for an energy storage system, characterized in that, The energy storage system includes a load, an energy storage converter, an energy storage battery, and a power distribution gateway; the energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway; A switching switch is provided between the energy storage converter and the power distribution gateway; The device includes: An extraction module is used to acquire the voltage signal of the power grid and extract the voltage parameters corresponding to the power grid based on the voltage signal. The voltage parameters include at least voltage amplitude, frequency and phase parameters. The determination module is used to determine a first target state corresponding to the power grid based on the voltage parameters: if at least one of the following occurs, the voltage amplitude does not meet the preset amplitude range, the frequency does not meet the preset frequency range, and the phase parameter does not meet the preset parameter range, the first target state is determined to be an off-grid state; if the voltage amplitude meets the preset amplitude range, the frequency meets the preset frequency range, and the phase parameter meets the preset parameter range, the first target state is determined to be a grid-connected state. The determining module is further configured to acquire the current signal and power signal of the power grid, and determine the second target state and the third target state of the power grid based on the current signal and the power signal, respectively; the voltage signal, the current signal and the power signal are preset with corresponding weight values; if the first target state, the second target state and the third target state are consistent, then the consistent state is determined as the target state of the power grid; if at least two of the first target state, the second target state and the third target state are inconsistent, then: the weight values ​​corresponding to each signal determined to be in the grid-connected state are summed to obtain the comprehensive weight value of the grid-connected state; the weight values ​​corresponding to each signal determined to be in the off-grid state are summed to obtain the comprehensive weight value of the off-grid state; the state with the higher comprehensive weight value is determined as the target state of the power grid; The adjustment module is used to adjust the output voltage of the energy storage converter until the output voltage meets the target voltage parameters when the target state is off-grid state, using preset standard grid parameters as the target voltage parameters; wherein, the preset standard grid parameters include target voltage amplitude, target frequency and target phase parameters; The adjustment module is also used to adjust the voltage output of the energy storage converter based on the voltage amplitude, frequency and phase parameters included in the voltage parameters when the target state is grid-connected, until the output voltage meets the voltage amplitude, frequency and phase parameters; The switching module is used to control the switching switch to switch states based on the target state after the voltage adjustment of the energy storage converter is completed, so that the energy storage converter can exchange electrical energy with the load or the power grid.

4. An energy storage system, characterized in that, The energy storage system includes a load, an energy storage converter, an energy storage battery, and a power distribution gateway; The energy storage battery is connected to the energy storage converter, and the energy storage converter is connected to the load and the power grid through the power distribution gateway; The energy storage system is used to perform the steps of the method according to claim 1 or 2.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method of claim 1 or 2.

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