Energy storage system and control method

Abstract

According to the energy storage system and the control method provided by the invention, under the condition that the energy storage system is switched to off-grid operation, a controller firstly obtains bus voltage data, performs preliminary adjustment by using a first conversion module, and tries to increase the bus voltage to a preset value, thereby providing initial voltage support. And then, the controller judges whether the adjusting capability of the second conversion module needs to be started or not, and ensures that the photovoltaic module participates in bus voltage regulation and control when needed. When it is judged that the bus voltage is needed, the controller coordinates the first conversion module and the second conversion module to work together, the bus voltage is stably increased to a target value, and the situation that the bus voltage is suddenly reduced due to load impact or insufficient regulation and control capacity of a single module is avoided. Smooth switching between the grid-connected mode and the off-grid mode can be achieved without cutting off the load, and the risk of power supply interruption caused by overcurrent protection or voltage drop in the prior art is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to an energy storage system and a control method. Background Art

[0002] The household energy storage system is a distributed energy management solution that is mainly used in home environments to store and manage electrical energy. The core function of the household energy storage system is to store excess electrical energy (for example, electrical energy generated by photovoltaic power generation) for subsequent use, and to provide a stable power supply for household loads during power outages or peak power consumption.

[0003] In the prior art, there is a technical problem of inconvenient on-grid and off-grid switching in household energy storage systems. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies and provide an energy storage system and a control method to solve the technical problem of inconvenient on-grid and off-grid switching in the related art.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides an energy storage system, the system comprising an energy storage module and a photovoltaic module, the system further comprising:

[0007] A first conversion module, one end of which is connected to the busbar, and the other end of which is connected to the energy storage module; wherein the first conversion module is a module for performing a voltage boost process on the output voltage of the energy storage module;

[0008] A second conversion module, one end of which is connected to the busbar, and the other end of which is connected to the photovoltaic module; wherein the second conversion module is a module for performing a voltage boost process on the output voltage of the photovoltaic module;

[0009] The controller, when detecting that the energy storage system switches to off-grid operation, obtains the bus voltage data of the energy storage system, controls the first conversion module to adjust the bus voltage data to try to increase the bus voltage data to a preset value, and then determines whether to control the second conversion module to adjust the bus voltage data. If the determination is yes, the controller controls the first conversion module and the second conversion module to jointly increase the bus voltage data to the preset value.

[0010] In a second aspect, the present invention provides a control method for an energy storage system, wherein the energy storage system comprises at least an energy storage module, a photovoltaic module, a first conversion module connected to the energy storage module, and a second conversion module connected to the photovoltaic module; the method comprises:

[0011] When it is detected that the energy storage system is switched to off-grid operation, the bus voltage data of the energy storage system is obtained;

[0012] Controlling the first conversion module to adjust the bus voltage data to try to increase the bus voltage data to a preset value; wherein the first conversion module is a module for performing a voltage boost process on the output voltage of the energy storage module;

[0013] Determine whether to control the second conversion module to adjust the bus voltage data; wherein the second conversion module is a module for performing a voltage boost process on the output voltage of the photovoltaic module;

[0014] If the judgment is yes, the first conversion module and the second conversion module are controlled to jointly increase the bus voltage data to a preset value.

[0015] Beneficial effects:

[0016] In the present invention, when the energy storage system switches to off-grid operation, the controller first obtains the bus voltage data and uses the first conversion module to perform preliminary adjustments, trying to increase the bus voltage to a preset value, thereby providing initial voltage support. Subsequently, the controller determines whether it is necessary to enable the adjustment capability of the second conversion module to ensure that the photovoltaic module participates in bus voltage regulation when needed. When it is determined to be necessary, the controller coordinates the first conversion module and the second conversion module to work together to smoothly increase the bus voltage to the target value, thereby avoiding the bus voltage from suddenly dropping due to load shock or insufficient regulation capability of a single module. The present invention can achieve smooth switching between grid-connected and off-grid modes without cutting off the load, effectively avoiding the risk of power supply interruption due to overcurrent protection or voltage drop in the prior art, significantly improving the stability of the energy storage system and user experience, while reducing operational complexity and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a block diagram of a household energy storage system in the related art provided by an embodiment of the present invention;

[0018] Figure 2 is a block diagram of an energy storage system provided by an embodiment of the present invention;

[0019] Figure 3 is a block diagram of an energy storage system provided by an embodiment of the present invention;

[0020] Figure 4 is a flow chart of a control method of an energy storage system provided by an embodiment of the present invention;

[0021] Figure 5 is a flow chart of a control method of an energy storage system provided by an embodiment of the present invention;

[0022] In the attached figure:

[0023] First conversion module: 100;

[0024] Energy storage module: 200;

[0025] Second conversion module: 300;

[0026] Photovoltaic modules: 400;

[0027] Controller: 500;

[0028] Voltage acquisition module: 600;

[0029] Switch module:700. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0031] In the relevant technology, household energy storage systems are usually composed of photovoltaic panels, energy storage modules (batteries), inverter modules and related conversion modules. The main functions of the household energy storage system include supplying power to household loads, realizing local storage and use of energy, and interacting with the power grid (grid connection).

[0032] like Figure 1 As shown, the household energy storage system may include:

[0033] Photovoltaic conversion module: connected to photovoltaic panels to boost the DC power generated by the photovoltaic panels to the DC bus voltage.

[0034] Energy storage conversion module: connects to energy storage batteries, adjusts the DC voltage output by the batteries to meet the requirements of the DC bus, and supports step-up and step-down conversion.

[0035] Grid-connected conversion module: responsible for converting the DC bus voltage into AC voltage to meet the power supply requirements of the AC load, while allowing the household energy storage system to conduct two-way energy interaction with the power grid.

[0036] When the system is running, the DC bus voltage is the core of the energy management of the entire household energy storage system. Whether in grid-connected mode or off-grid mode, the stability of the bus voltage directly determines the power supply quality of the load.

[0037] In the relevant technology, household energy storage systems usually operate in a "grid-connected first" mode. When a power outage is detected, they will switch to off-grid mode to provide independent power supply for household loads. At the moment of switching from grid-connected to off-grid, due to the limitations of the energy storage module's regulation ability, the bus voltage may drop sharply due to load changes or instantaneous shocks. If the load is not cut off, when the bus voltage drops, it will trigger the overcurrent protection of the energy storage module or photovoltaic module, resulting in power outage or equipment damage.

[0038] In order to avoid the above problems, the existing technology usually requires users to manually disconnect the load and manually connect it after the household energy storage system completes the switch. This method increases the user's operating burden and has certain risks, especially for non-professional users.

[0039] Therefore, when switching from grid-connected to off-grid, existing household energy storage systems have the risk of overcurrent protection caused by a sudden drop in bus voltage. To avoid this problem, the load needs to be manually cut off. However, this operation method is complicated and inconvenient, increasing maintenance costs and difficulty of use.

[0040] Therefore, in the related art, there is a technical problem of inconvenient on-grid and off-grid switching in household energy storage systems.

[0041] like Figure 2 and Figure 3 The present embodiment provides an energy storage system, the system comprising an energy storage module and a photovoltaic module, the system further comprising:

[0042] The first conversion module 100 has one end connected to the busbar and the other end connected to the energy storage module 200 ; wherein the first conversion module 100 is a module for performing a voltage boost process on the output voltage of the energy storage module 200 .

[0043] In this embodiment, the first conversion module 100 can be a bidirectional converter, which can both boost and buck, and can achieve bidirectional flow of energy. The bidirectional converter can boost the output voltage of the energy storage battery to the DC bus voltage, and can also supply power to the energy storage battery from the DC bus when necessary. Specifically, the bidirectional converter can be a Buck-Boost converter. The Buck-Boost converter can achieve dual functions of boosting and bucking. When the output voltage of the energy storage battery is low, it can boost; when the energy storage battery is charged, it can buck to keep the output voltage within a stable range.

[0044] In this implementation, the first conversion module 100 may be a resonant converter, for example, an LLC resonant converter.

[0045] The second conversion module 300 has one end connected to the busbar and the other end connected to the photovoltaic module 400 ; wherein the second conversion module is a module for performing a voltage boost process on the output voltage of the photovoltaic module 400 .

[0046] In this embodiment, the second conversion module 300 may be a unidirectional converter. Specifically, the unidirectional converter may be a Boost converter. The Boost converter is a step-up DC-DC converter used to increase the lower output voltage of the photovoltaic module to a high voltage suitable for the DC bus.

[0047] In this embodiment, the second conversion module 300 may be a bidirectional converter, which can both boost and buck voltage, and can achieve bidirectional flow of energy. The bidirectional converter can boost the output voltage of the photovoltaic module to the DC bus voltage, and can also supply power to the photovoltaic module from the DC bus when necessary. Specifically, the bidirectional converter may be a Buck-Boost converter.

[0048] In this embodiment, the second converter may also be a multi-phase Boost converter.

[0049] In this embodiment, the second converter may also be a full-bridge converter.

[0050] The controller, when detecting that the energy storage system switches to off-grid operation, obtains the bus voltage data of the energy storage system, controls the first conversion module 100 to adjust the bus voltage data to try to increase the bus voltage data to a preset value, and then determines whether to control the second conversion module 300 to adjust the bus voltage data. If the determination is yes, the controller controls the first conversion module 100 and the second conversion module 300 to jointly increase the bus voltage data to the preset value.

[0051] In this embodiment, the controller 500 may be a programmable logic controller (PLC).

[0052] In this embodiment, the controller 500 may be an industrial computer (IPC).

[0053] In this embodiment, the controller 500 may be an embedded microcontroller (MCU).

[0054] In this embodiment, the controller 500 may be a digital signal processor (DSP).

[0055] This embodiment introduces the first conversion module 100 and the second conversion module 300 to perform a voltage boost process on the output voltages of the energy storage module 200 and the photovoltaic module 400, respectively, and realizes the coordinated control of the two conversion modules through the controller 500, which can effectively solve the technical problem of inconvenient on-grid and off-grid switching in the prior art. When the energy storage system switches to off-grid operation, the controller 500 first obtains the bus voltage data and uses the first conversion module 100 to perform preliminary adjustments, trying to increase the bus voltage to a preset value, thereby providing initial voltage support. Subsequently, the controller 500 determines whether it is necessary to enable the adjustment capability of the second conversion module 300 to ensure that the photovoltaic module 400 participates in bus voltage regulation when necessary. When it is determined to be necessary, the controller coordinates the first conversion module 100 and the second conversion module 300 to work together to smoothly increase the bus voltage to the target value, thereby avoiding the bus voltage from suddenly dropping due to load shock or insufficient regulation capability of a single module. This embodiment can achieve smooth switching between grid-connected and off-grid modes without cutting off the load, effectively avoiding the risk of power supply interruption due to overcurrent protection or voltage drop in the prior art, significantly improving the stability of the system and user experience, while reducing operational complexity and maintenance costs.

[0056] In some embodiments, the system further comprises:

[0057] The voltage acquisition module 600 has one end connected to the controller 500 for signal connection, and the other end connected to the bus, and is connected between one end of the first conversion module 100 and one end of the second conversion module 300 .

[0058] In this embodiment, by introducing a voltage acquisition module 600 into the energy storage system, one end of the module is connected to the controller 500 signal, the other end is connected to the bus, and is arranged between the first conversion module 100 and the second conversion module 300, so that the energy storage system can collect bus voltage data in real time and feed it back to the controller. This design significantly improves the accuracy and real-time performance of bus voltage monitoring, and provides key data support for the controller to dynamically adjust the first conversion module 100 and the second conversion module 300. With the help of the voltage acquisition module, the controller 500 can quickly respond to changes in bus voltage, and accurately determine whether it is necessary to coordinate the two conversion modules to work together according to the real-time status of the bus voltage, thereby effectively avoiding the sudden drop or overshoot of the bus voltage due to control delays or errors.

[0059] In some embodiments, the system further comprises:

[0060] The switch module 700 is disposed between the photovoltaic module 400 and the second conversion module 300 .

[0061] In this embodiment, by setting a switch module 700 between the photovoltaic module 400 and the second conversion module 300, it is possible to flexibly control whether the photovoltaic module 400 participates in the regulation of the bus voltage, thereby significantly improving the operational flexibility and stability of the energy storage system. When the energy storage system is in the grid-connected mode, the switch module can disconnect the photovoltaic module 400 from the second conversion module 300 to prevent the photovoltaic module 400 from interfering with the bus voltage; while in the off-grid mode, the switch module 700 can quickly connect the photovoltaic module to the second conversion module 300, so that the photovoltaic module 400 can participate in the regulation of the bus voltage in a timely manner. In an emergency, the switch module 700 can also be used as a safety protection device to quickly cut off the connection between the photovoltaic module 400 and the energy storage system to prevent system failures caused by abnormal output of the photovoltaic module 400. This embodiment not only optimizes the operating process of the system when switching between the grid-connected and off-grid modes, but also improves the safety and reliability of the energy storage system, reduces dependence on user operations, and effectively solves the problem of insufficient access flexibility of the photovoltaic module 400 in the prior art.

[0062] In this embodiment, the switch module 700 may be a manual rotary switch.

[0063] In this embodiment, the switch module 700 may be an electromagnetic relay.

[0064] In this embodiment, the switch module 700 may be a mechanical circuit breaker.

[0065] like Figure 4 The present embodiment provides a control method for an energy storage system, wherein the energy storage system comprises at least an energy storage module, a photovoltaic module, a first conversion module connected to the energy storage module, and a second conversion module connected to the photovoltaic module; the execution subject of the method may be a controller, and the method may include:

[0066] Step S12: when it is detected that the energy storage system is switched to off-grid operation, bus voltage data of the energy storage system is obtained.

[0067] In this embodiment, the detection of the energy storage system switching to off-grid operation can be represented by the controller monitoring the grid state in real time through the connected grid detection module. When it is detected that the grid voltage is abnormal (for example, the voltage is lower than the set threshold) or the grid frequency deviates from the normal range, it is represented that the energy storage system switches to off-grid operation.

[0068] In this embodiment, the controller can also detect whether the energy storage system is switched to off-grid operation by monitoring the operating status of the grid-connected inverter. Specifically, if the grid-connected inverter detects that the grid is out of power or does not meet the grid-connected conditions (for example, the grid waveform is distorted or disconnected), and sends an off-grid signal to the controller, the controller can confirm that the energy storage system is switched to off-grid operation.

[0069] In this embodiment, the controller can also detect whether the energy storage system has switched to off-grid operation by collecting and analyzing the state signal (e.g., disconnection signal) of the grid connection switch. Specifically, the state signal can determine whether the energy storage system has been physically disconnected from the grid, thereby determining that the energy storage system has switched to off-grid operation.

[0070] In this embodiment, the acquisition of the bus voltage data of the energy storage system can be expressed as collecting the bus voltage data of the energy storage system through a voltage detection module preset in the energy storage system. Specifically, the voltage detection module can be a resistor voltage divider circuit + analog-to-digital converter, which reduces the high voltage to a low voltage (analog signal) suitable for subsequent processing. The analog signal can be converted into a digital signal through an analog-to-digital converter, and the digital signal is input into the controller. The voltage detection module can also be a Hall effect voltage sensor or a photoelectric isolation voltage sensor.

[0071] In this embodiment, the energy storage module may be a lithium-ion battery module.

[0072] In this embodiment, the energy storage module may be a lead-acid battery module.

[0073] In this embodiment, the energy storage module may be an all-vanadium liquid flow battery module.

[0074] In this embodiment, the energy storage module may also be a super capacitor module.

[0075] In this embodiment, the energy storage module may also be a solid-state battery module.

[0076] In this embodiment, the photovoltaic module may be a monocrystalline silicon photovoltaic module.

[0077] In this embodiment, the photovoltaic module may be a polycrystalline silicon photovoltaic module.

[0078] In this embodiment, the photovoltaic module may be a thin-film photovoltaic module.

[0079] In this implementation, the photovoltaic module may also be a fixed installation photovoltaic module.

[0080] In this embodiment, the photovoltaic module may also be a tracking photovoltaic module.

[0081] In this embodiment, the first conversion module can be a bidirectional converter, which can both boost and buck, and can achieve bidirectional flow of energy. The bidirectional converter can boost the output voltage of the energy storage battery to the DC bus voltage, and can also supply power to the energy storage battery from the DC bus when necessary. Specifically, the bidirectional converter can be a Buck-Boost converter. The Buck-Boost converter can achieve dual functions of boosting and bucking. When the output voltage of the energy storage battery is low, it can boost; when the energy storage battery is charged, it can buck to keep the output voltage within a stable range.

[0082] In this embodiment, the first conversion module may be a resonant converter, for example, an LLC resonant converter.

[0083] In this embodiment, the second conversion module may be a unidirectional converter. Specifically, the unidirectional converter may be a Boost converter. The Boost converter is a step-up DC-DC converter used to increase the lower output voltage of the photovoltaic module to a high voltage suitable for the DC bus.

[0084] In this embodiment, the second conversion module may be a bidirectional converter, which can both boost and buck voltage, and can achieve bidirectional flow of energy. The bidirectional converter can boost the output voltage of the photovoltaic module to the DC bus voltage, and can also supply power to the photovoltaic module from the DC bus when necessary. Specifically, the bidirectional converter may be a Buck-Boost converter.

[0085] In this embodiment, the second converter may also be a multi-phase Boost converter.

[0086] In this embodiment, the second converter may also be a full-bridge converter.

[0087] In this embodiment, the controller may be a programmable logic controller (PLC).

[0088] In this embodiment, the controller may be an industrial computer (IPC).

[0089] In this embodiment, the controller may be an embedded microcontroller unit (MCU).

[0090] In this embodiment, the controller may be a digital signal processor (DSP).

[0091] Step S14: controlling the first conversion module to adjust the bus voltage data to try to increase the bus voltage data to a preset value; wherein the first conversion module is a module for performing a voltage boost process on the output voltage of the energy storage module.

[0092] In this embodiment, the control action can be represented by the controller sending a control signal to the first conversion module (eg, Buck-Boost converter) to increase the output voltage of the first conversion module, thereby increasing the bus voltage data to a preset value.

[0093] In this implementation manner, the step of controlling the first conversion module to adjust the bus voltage data to attempt to increase the bus voltage data to a preset value may include:

[0094] First, the controller can calculate the difference data between the current bus voltage data and the preset value.

[0095] Then, the controller calculates the duty cycle required by the first conversion module based on the difference data, and then generates a control signal for quickly increasing the bus voltage to a preset value. The control signal (for example, a PWM signal) can be sent to the drive circuit of the first conversion module through a hardware interface (for example, a GPIO or a PWM module). The first conversion module adjusts the switching frequency or the on-time according to the received PWM signal to change the output voltage, thereby gradually increasing the bus voltage.

[0096] Finally, when the bus voltage data is close to the preset value (for example, reaching 95% of the preset value), the fine-tuning stage can be entered. After entering the fine-tuning stage, the controller can adjust the duty cycle based on a closed-loop control strategy (for example, PID control or sliding mode control), and further adjust the control signal to gradually reduce the difference data and prevent overshoot or oscillation.

[0097] In this implementation manner, the step of controlling the first conversion module to adjust the bus voltage data to attempt to increase the bus voltage data to a preset value may also include:

[0098] First, the controller further collects the output data (output circuit data, output voltage data) of the energy storage module and the power data of the load, and then predicts the change trend of the bus voltage at future moments based on the further collected data and bus voltage data and the preset prediction model.

[0099] Then, the controller optimizes and calculates the control parameters (duty cycle or frequency) of the first conversion module based on the difference between the predicted bus voltage value and the preset value, and generates a corresponding control signal. The control signal is sent to the drive circuit of the first conversion module through the hardware interface to adjust the output voltage.

[0100] Finally, after the first conversion module performs the adjustment, the controller collects the new bus voltage data in real time and updates the prediction model. Through rolling optimization and real-time adjustment, the controller continuously corrects the control signal so that the bus voltage gradually approaches the preset value, achieving precise regulation while avoiding overshoot and oscillation.

[0101] In this implementation manner, the step of controlling the first conversion module to adjust the bus voltage data to attempt to increase the bus voltage data to a preset value may also include:

[0102] First, the controller can calculate the difference between the current bus voltage data and the preset value. At the same time, the output capacity of the energy storage module and the load power change trend are analyzed. Based on these data, the controller dynamically calculates a reference voltage value (different from the preset value) and uses the reference voltage value as the temporary target value of the bus voltage to optimize the regulation process.

[0103] Then, the controller compares the difference between the current bus voltage and the reference voltage value, and calculates the target duty cycle of the first conversion module based on the difference value. The generated control signal. The reference voltage value can be dynamically adjusted to adapt to load changes and real-time fluctuations in the capacity of the energy storage module.

[0104] Finally, when the bus voltage gradually approaches the reference voltage, the controller will recalculate the new reference voltage and gradually approach the preset value. In the final stage, the controller can adjust the duty cycle based on a closed-loop control strategy (e.g., PID control) to ensure that the bus voltage stably reaches and maintains the preset value.

[0105] In this implementation, the preset value may be a fixed voltage threshold, for example, 380V.

[0106] In this embodiment, the preset value may be a dynamic target voltage, which may be dynamically set according to real-time load demand.

[0107] In this embodiment, the preset value may be a graded voltage threshold. For example, multiple preset values ​​may be set as a basis for judgment. A first-level preset value (95% of rated voltage) is used to make an early judgment and start an early warning mechanism. A second-level preset value (90% of rated voltage) is used to trigger the adjustment of the second conversion module.

[0108] Step S16: Determine whether to control the second conversion module to adjust the bus voltage data; wherein the second conversion module is a module for performing a voltage boost process on the output voltage of the photovoltaic module.

[0109] It is understandable that, on the one hand, in an off-grid environment, the maintenance of the bus voltage mainly depends on the output of the energy storage battery and the first conversion module. However, the output capacity of the energy storage battery is limited and is often subject to the current remaining battery capacity, discharge rate and operating status (e.g., temperature, health status). When the load power demand is high (for example, multiple high-power household appliances in a household system are running at the same time), a single energy storage module may be difficult to provide sufficient voltage support. On the other hand, if the power supply is completely dependent on the energy storage battery, it may also cause the energy storage battery to be overloaded or deeply discharged, shortening the life of the energy storage battery. Therefore, the second conversion module is enabled to share the load using the output voltage of the photovoltaic module to reduce the pressure on the energy storage module. On the other hand, the load in the household energy storage system often changes dynamically. The load may increase significantly in a short period of time, for example, multiple high-power devices (air conditioners, electric water heaters) are started at the same time. Therefore, a single energy storage module may find it difficult to respond quickly to such load changes.

[0110] In this implementation, the adjustment action may be represented by the controller controlling the second conversion module to increase the bus voltage data.

[0111] In this embodiment, the control action may be represented as the controller generating a control signal and sending the control signal to the second conversion module, so that the second conversion module performs a corresponding adjustment action.

[0112] In this implementation, the controller may determine whether to control the second conversion module to adjust the bus voltage data by the following method, specifically:

[0113] Based on a preset judgment rule and the bus voltage data adjusted by the first conversion module, it is determined whether to control the second conversion module to adjust the bus voltage data.

[0114] In this embodiment, the preset judgment rule can be a counting rule, for example, re-acquiring the bus voltage data of the energy storage system (the bus voltage data adjusted by the first conversion module) for multiple times, and then judging whether the re-acquired bus voltage data is less than the preset value, if it is less than the preset value, then increasing the count times. After multiple re-acquisitions and comparisons, further judging whether the current count times is greater than or equal to the times threshold. If it is greater than or equal to the times threshold, then judging to control the second conversion module to adjust the bus voltage data.

[0115] In this embodiment, the preset judgment rule may be a time window rule. For example, first, the bus voltage data of the energy storage system is acquired multiple times within the preset time window. Then, the average value of the bus voltage data within the preset time window is calculated; then, it is determined whether the average value reaches the preset value; finally, when the average value reaches the preset value, it is determined that the second conversion module needs to be controlled to adjust the bus voltage data.

[0116] In this embodiment, the preset judgment rule may be a rule based on the voltage change rate. For example, by analyzing the rate of change of the bus voltage data (the slope of the voltage), it is determined whether to control the second conversion module to adjust the bus voltage data. For another example, the bus voltage data of the energy storage system may be obtained multiple times, and then the change rate may be calculated. If the change rate is less than the preset rate threshold (indicating that the voltage rises slowly), it is determined that the second conversion module needs to be controlled for adjustment.

[0117] In this embodiment, the preset judgment rule may also be a judgment rule combining the remaining capacity of the energy storage module and the available power generation capacity of the photovoltaic module. For example, first, the remaining capacity (SOC) of the energy storage module and the current output capacity of the photovoltaic module are obtained. Then, the bus voltage time that the energy storage module can support and the additional voltage support that the photovoltaic module can provide are calculated. Finally, if the support time of the energy storage module is insufficient or the output capacity of the photovoltaic module is sufficient, it is determined that the second conversion module needs to be controlled.

[0118] In this embodiment, the preset judgment rule may also be a judgment rule based on load power fluctuation. For example, first, the controller may collect the load power in real time. Then, the controller may calculate the load power fluctuation amplitude. Finally, if the fluctuation amplitude exceeds the preset power threshold, it is determined that the second conversion module needs to be controlled for adjustment.

[0119] Step S18: When the judgment is yes, control the first conversion module and the second conversion module to jointly increase the bus voltage data to a preset value.

[0120] In this implementation, the controller may control the first conversion module and the second conversion module to jointly increase the bus voltage data to a preset value in the following manner, specifically:

[0121] First, the controller calculates the voltage difference between the current bus voltage data and the preset value. Then, based on the voltage difference, the controller determines the first target output voltage of the first conversion module and the second target output voltage of the second conversion module respectively. Then, the controller generates a first control signal based on the first target output voltage and generates a second control signal based on the second target output voltage; finally, the controller sends the first control signal to the first conversion module and sends the second control signal to the second conversion module to adjust the output voltages of the first conversion module and the second conversion module.

[0122] In this implementation, the controller may also control the first conversion module and the second conversion module to jointly increase the bus voltage data to a preset value in the following manner, specifically:

[0123] First, the controller can determine the current working status data of the energy storage module and the photovoltaic module (for example, the remaining capacity of the energy storage module, the power generation capacity of the photovoltaic module). Then, the controller generates the output priority ratio of the first conversion module and the second conversion module based on the current working status data of the energy storage module and the photovoltaic module. Finally, the controller can calculate the target output voltage of the first conversion module and the second conversion module respectively based on the output priority ratio, and generate corresponding control signals. It can be understood that the output priority ratio can be adjusted dynamically.

[0124] In this implementation, the controller may also control the first conversion module and the second conversion module to jointly increase the bus voltage data to a preset value in the following manner, specifically:

[0125] First, the controller collects the output power upper limit of the energy storage module and photovoltaic module, as well as the load demand power in real time.

[0126] Then, the controller divides the load demand power according to the output power upper limits of the energy storage module and the photovoltaic module, divides a part of it to the energy storage module to generate the target output power of the energy storage module, and divides the other part to the photovoltaic module to generate the target output power of the photovoltaic module.

[0127] Finally, the controller generates a control signal for the first conversion module based on the target output power of the energy storage module, and the controller generates a control signal for the second conversion module based on the target output power of the photovoltaic module.

[0128] In this implementation, the controller may also control the first conversion module and the second conversion module to jointly increase the bus voltage data to a preset value in the following manner, specifically:

[0129] First, the controller calculates the voltage difference between the current bus voltage data and a preset value, and determines whether the voltage difference exceeds a threshold value of the voltage difference.

[0130] Then, the controller performs a judgment, and if the voltage difference exceeds a threshold, the controller can simultaneously increase the switching frequency of the first conversion module and the second conversion module to quickly increase the bus voltage.

[0131] The control method provided in this embodiment achieves rapid response and precise stabilization of the bus voltage during the on-grid and off-grid switching of the energy storage system by regulating the output voltage of the first conversion module and the second conversion module in stages. By using the first conversion module to quickly try to increase the bus voltage to a preset value in the initial stage, and judging whether to link the second conversion module for further adjustment based on the regulation results, the problem of inconvenient on-grid and off-grid switching in traditional household energy storage systems is effectively solved, and system overcurrent protection failures caused by bus voltage fluctuations or drops are avoided. In addition, this method achieves on-grid and off-grid switching without cutting off the load connection, significantly reducing the system operation complexity and maintenance costs, while improving the reliability and safety of the system.

[0132] In some implementations, the step of determining whether to control the second conversion module to adjust the bus voltage data includes:

[0133] Based on a preset judgment rule and the bus voltage data adjusted by the first conversion module, it is determined whether to control the second conversion module to adjust the bus voltage data.

[0134] In this embodiment, the preset judgment rule can be a counting rule, for example, re-acquiring the bus voltage data of the energy storage system (the bus voltage data adjusted by the first conversion module) for multiple times, and then judging whether the re-acquired bus voltage data is less than the preset value, if not less than the preset value, then increasing the count times. After multiple re-acquisitions and comparisons, further judging whether the current count times is greater than or equal to the times threshold. If it is greater than or equal to the times threshold, then judging to control the second conversion module to adjust the bus voltage data.

[0135] In this embodiment, the preset judgment rule may be a time window rule. For example, first, the bus voltage data of the energy storage system is acquired multiple times within the preset time window. Then, the average value of the bus voltage data within the preset time window is calculated; then, it is determined whether the average value reaches the preset value; finally, when the average value reaches the preset value, it is determined that the second conversion module needs to be controlled to adjust the bus voltage data.

[0136] In this embodiment, the method can dynamically monitor the actual state of the bus voltage, ensuring that the energy storage system promptly starts the second conversion module to intervene in the adjustment when the voltage is insufficient, thereby quickly compensating the bus voltage and avoiding instability of the energy storage system caused by delayed adjustment. Secondly, the judgment rule is based on preset rules, such as counting rules or time window rules, and can be flexibly adjusted according to the changing trend of the bus voltage, which not only avoids unnecessary module startup, reduces the load pressure of photovoltaic modules and conversion modules, but also improves the energy efficiency and life of the energy storage system. Finally, this intelligent judgment based on data and rules significantly improves the adjustment accuracy and responsiveness of the energy storage system, ensuring that the bus voltage can be stably maintained within the target range when the load changes or the environment fluctuates, thereby enhancing the stability and reliability of the entire energy storage system.

[0137] In some embodiments, the step of judging whether to control the second conversion module to adjust the bus voltage data based on a preset judgment rule and the bus voltage data adjusted by the first conversion module includes:

[0138] Step S162: reacquire the bus voltage data of the energy storage system multiple times.

[0139] Step S164: Determine whether the re-acquired bus voltage data is less than a preset value.

[0140] Step S166: if the answer is yes, increase the count times; wherein the count times represent the number of times the bus voltage data does not reach a preset value.

[0141] Step S168: Determine whether the current count times is greater than or equal to the times threshold.

[0142] In this embodiment, the number threshold may be a fixed number threshold, for example, 5 times, 10 times, etc. When the counted number reaches or exceeds the fixed value, the adjustment operation on the second conversion module is triggered.

[0143] In this embodiment, the number threshold may be a dynamically adjusted number threshold. For example, when the load power is large or fluctuates frequently, the number threshold may be reduced (for example, 3 times) to speed up the regulation response.

[0144] Step S169: When the counted number is greater than or equal to the number threshold, it is determined that the second conversion module needs to be controlled to adjust the bus voltage data.

[0145] In this embodiment, by acquiring the bus voltage data multiple times and combining the counting rules, it is determined whether it is necessary to control the second conversion module for adjustment, which has significant beneficial effects. First, this method avoids the contingency or misjudgment of single sampling data by continuously monitoring the changing trend of the bus voltage data, and improves the reliability of the judgment. Secondly, by setting the counting threshold, it can accurately respond to the situation where the bus voltage has not reached the preset value for a long time, ensuring that the second conversion module intervenes in time when necessary, quickly compensates the bus voltage, and maintains system stability. In addition, this method can also avoid the frequent triggering of the start-up of the second conversion module due to voltage fluctuations in a short period of time, thereby reducing the operating frequency and loss of the module and extending the life of the equipment. Overall, this implementation method achieves a balance between accurate judgment and efficient regulation, significantly improving the intelligence level and operating efficiency of the energy storage system.

[0146] In some embodiments, the step of judging whether to control the second conversion module to adjust the bus voltage data based on a preset judgment rule and the bus voltage data adjusted by the first conversion module includes:

[0147] Within a preset time window, the bus voltage data of the energy storage system is re-acquired multiple times.

[0148] In this embodiment, the preset time window may be a fixed time window. Specifically, the time window may be set to a fixed duration, for example, 1 second, 5 seconds, 30 seconds, etc. Within the fixed time interval, the controller may collect bus voltage data multiple times.

[0149] In this embodiment, the preset time window may be a dynamic time window. Specifically, when the load power is large or fluctuates frequently, the time window may be reduced (e.g., 0.5 seconds). Correspondingly, when the load power is small, the time window may be increased (e.g., 10 seconds).

[0150] In this embodiment, the preset time window may be a sliding time window. Specifically, each time the bus voltage data is collected, the time window moves forward for a short period of time.

[0151] Calculate the average value of the bus voltage data within the preset time window.

[0152] It is determined that the average value reaches a preset value.

[0153] When the average value reaches a preset value, it is determined that the second conversion module needs to be controlled to adjust the bus voltage data.

[0154] This implementation method obtains bus voltage data multiple times within a preset time window and calculates its average value, and determines whether to control the second conversion module for adjustment in combination with the preset value. First, this implementation method uses the average value of the data within the time window as the basis for judgment, which can effectively filter out the impact of short-term fluctuations or transient interference, and avoid misjudgment caused by occasional voltage fluctuations, thereby improving the stability and reliability of the energy storage system judgment. Secondly, through the flexible setting of the time window, this method can adapt to the load characteristics and fluctuation frequency in different operating scenarios, ensuring that the adjustment operation can not only respond to the problem of insufficient voltage in a timely manner, but also reduce unnecessary frequent startups and extend the service life of the module. In addition, the judgment mechanism based on the average value also improves the overall efficiency of bus voltage regulation, ensuring that the energy storage system can continue to maintain the smooth and stable operation of the bus voltage in a dynamic load environment.

[0155] like Figure 5 As shown, in some embodiments, the step of controlling the first conversion module and the second conversion module to jointly increase the bus voltage data to a preset value includes:

[0156] Step S182: Calculate the voltage difference between the current bus voltage data and the preset value.

[0157] Step S184: Based on the voltage difference, respectively determine a first target output voltage of the first conversion module and a second target output voltage of the second conversion module.

[0158] In this implementation, the determining, based on the voltage difference, respectively the first target output voltage of the first conversion module and the second target output voltage of the second conversion module may include:

[0159] First, the controller determines the available voltage regulation range of the energy storage module and the photovoltaic module under current operating conditions.

[0160] Then, the controller calculates the voltage distribution ratio of the voltage difference between the first conversion module and the second conversion module based on the available voltage adjustment range;

[0161] Finally, the controller determines a first target output voltage of the first conversion module and a second target output voltage of the second conversion module based on the voltage distribution ratio and the voltage difference.

[0162] In this implementation manner, determining the first target output voltage of the first conversion module and the second target output voltage of the second conversion module respectively based on the voltage difference may also include:

[0163] First, the controller obtains the power upper limits of the energy storage module and the photovoltaic module.

[0164] In this embodiment, the controller can directly obtain the power upper limit reported by the module through the communication interface (e.g., CAN bus, RS485) with the energy storage module and the photovoltaic module. For example, the energy storage module can obtain the real-time maximum output power data provided by the module internal management unit (BMS, battery management system). The photovoltaic module can obtain the real-time maximum output power data provided by the MPPT (maximum power point tracking) control unit.

[0165] Then, the controller sets the voltage distribution ratio coefficient of the first conversion module and the second conversion module based on the power upper limit to distribute the voltage difference. For example, if the power upper limit of the energy storage module is large, the larger voltage difference is preferentially allocated to the first conversion module. Correspondingly, if the power upper limit of the photovoltaic module is large, the larger voltage difference is preferentially allocated to the second conversion module.

[0166] Finally, the controller distributes the voltage difference based on the corresponding distribution proportional coefficient, thereby obtaining a first target output voltage and a second target output voltage. For example, the first target output voltage may be the output voltage of the first conversion module plus the distributed voltage difference, and correspondingly, the second target output voltage may be the output voltage of the second conversion module plus the distributed voltage difference.

[0167] In this implementation manner, determining the first target output voltage of the first conversion module and the second target output voltage of the second conversion module respectively based on the voltage difference may also include:

[0168] The controller obtains the power demand of the load, and then sets the voltage distribution ratio coefficient of the first conversion module and the second conversion module based on the power demand of the load. For example, if the power demand of the load is higher, a higher voltage distribution ratio coefficient can be assigned to the module with a faster response speed. If the power demand of the load is lower, the voltage distribution ratio coefficient can be set evenly.

[0169] In this implementation manner, determining the first target output voltage of the first conversion module and the second target output voltage of the second conversion module respectively based on the voltage difference may further include:

[0170] First, the controller obtains the output voltages of the first conversion module and the second conversion module.

[0171] The controller then distributes the voltage difference with the goal of minimizing the bus voltage error.

[0172] In a specific implementation, the objective function can be set as follows:

[0173] MinimizeE=|U set -(U dc+α1·ΔU+α2·ΔU)|

[0174] In the formula, U set It can be expressed as a preset value, U dc It can be expressed as the current bus voltage, α1 and α2 are the voltage distribution ratio coefficients of the first conversion module and the second conversion module, and ΔU is the voltage difference.

[0175] The voltage difference may be allocated with the goal of minimizing the bus voltage error.

[0176] The voltage distribution ratio coefficient may be calculated by an iterative or optimization algorithm so as to minimize the error when the first conversion module and the second conversion module are coordinated and adjusted.

[0177] Step S186 : generating a first control signal based on the first target output voltage and generating a second control signal based on the second target output voltage.

[0178] In this implementation, the step of generating a first control signal based on the first target output voltage and generating a second control signal based on the second target output voltage may include:

[0179] First, in the initial boost stage, the controller determines the initial duty ratios of the first conversion module and the second conversion module based on feedforward control.

[0180] Next, the controller generates initial control signals of the first conversion module and the second conversion module respectively according to the initial duty cycle and sends the initial control signals to the first conversion module and the second conversion module, so as to control the first conversion module and the second conversion module to perform a boost operation.

[0181] Then, the controller determines the error data between the current bus voltage data and the preset value after the initial boost phase ends;

[0182] Next, the controller dynamically adjusts the initial duty ratios of the first conversion module and the second conversion module based on the error data to obtain a corrected duty ratio;

[0183] Finally, the controller generates correction control signals of the first conversion module and the second conversion module respectively according to the corrected duty cycle and sends them to the first conversion module and the second conversion module, so as to stabilize the bus voltage data to a preset value.

[0184] In this implementation, the step of generating a first control signal based on the first target output voltage and generating a second control signal based on the second target output voltage may also include:

[0185] First, the controller can calculate the error between the first target output voltage and the actual output voltage of the first conversion module:

[0186] e1=U target,1 -U out,1

[0187] In the formula, U target,1 Expressed as the first target output voltage, U out,1 It is represented as the actual output voltage of the first conversion module.

[0188] The controller can calculate the error between the second target output voltage and the actual output voltage of the second conversion module:

[0189] e2=U target,2 -U out,2

[0190] In the formula, U target,2 Expressed as the second target output voltage, U out,2 It is represented as the actual output voltage of the second conversion module.

[0191] Then, for the first conversion module, the controller can calculate its duty cycle:

[0192]

[0193] In the formula, D1 represents the output duty cycle of the first conversion module, which represents the duty cycle value of the PWM signal, and K p Expressed as the proportional gain of the PID controller (reflecting the direct effect of the error on the output), K i Expressed as the integral gain of the PID controller (used to accumulate errors and eliminate the steady-state error of the system), K d It is represented as the differential gain of the PID controller (used to reflect the changing trend of the error and improve the rapidity and stability of the system response), and e1 is represented as the error between the first target output voltage and the actual output voltage of the first conversion module.

[0194] For the second conversion module, the controller can calculate the duty cycle:

[0195]

[0196] In the formula, D2 represents the output duty cycle of the second conversion module, which represents the duty cycle value of the PWM signal, and K p Expressed as the proportional gain of the PID controller (reflecting the direct effect of the error on the output), K i Expressed as the integral gain of the PID controller (used to accumulate errors and eliminate the steady-state error of the system), K dIt is represented as the differential gain of the PID controller (used to reflect the changing trend of the error and improve the rapidity and stability of the response), and e2 is represented as the error between the first target output voltage and the actual output voltage of the first conversion module.

[0197] Finally, the controller generates a PWM control signal according to the calculated duty cycles D1 and D2, and sends the signal to the first and second conversion modules respectively.

[0198] Step S188: Send the first control signal to the first conversion module and send the second control signal to the second conversion module to adjust the output voltages of the first conversion module and the second conversion module.

[0199] This implementation calculates the voltage difference and determines the target output voltage of the first conversion module and the second conversion module respectively, and then generates and sends a control signal to adjust the output voltage. In this implementation, firstly, the method realizes the accurate identification of the voltage regulation demand by accurately calculating the difference between the bus voltage and the preset value, thereby ensuring the efficiency and pertinence of the regulation operation. Secondly, by setting the target output voltages of the first conversion module and the second conversion module respectively, the two modules can work together, so that the energy storage module and the photovoltaic module can each play their own advantages and optimize the regulation efficiency. In addition, the step-by-step generation and transmission mechanism of the control signal can dynamically adapt to the real-time changes of the bus voltage, ensure that the regulation process is smooth and accurate, and avoid overshoot or oscillation. Overall, this implementation improves the response speed, stability and energy efficiency utilization of the bus voltage regulation, and provides a reliable guarantee for the safe and efficient operation of the energy storage system.

[0200] In some implementations, the step of determining a first target output voltage of the first conversion module and a second target output voltage of the second conversion module based on the voltage difference, respectively, includes:

[0201] Step S1842: Determine the available voltage adjustment range of the energy storage module and the photovoltaic module under the current operating conditions.

[0202] In this embodiment, the controller can directly read the rated parameters of the energy storage module and the photovoltaic module, and calculate the available voltage adjustment range in combination with the current operating state. Specifically, the controller can interact with the battery management system (BMS) to read the maximum and minimum output voltage range of the energy storage module. Then, based on the remaining capacity (SOC) of the current energy storage module, the available voltage range is calculated. Similarly, the controller can read the open circuit voltage and maximum power point voltage of the photovoltaic module. Then, combined with the current light intensity, the available voltage adjustment range is calculated.

[0203] In this embodiment, the controller may also collect voltage and current data of the energy storage module and the photovoltaic module in real time, and calculate the available voltage adjustment range in combination with the protection threshold.

[0204] Step S1844: Based on the available voltage adjustment range, calculating the voltage distribution ratio of the voltage difference between the first conversion module and the second conversion module.

[0205] In this embodiment, the available voltage adjustment range of the energy storage module can be defined as:

[0206] U range,storage =U max,storage -U min,storage

[0207] In this embodiment, the available voltage adjustment range of the photovoltaic module can be defined as:

[0208] U range,PV =U max,PV -U min,PV

[0209] Then, the voltage distribution ratio of the voltage difference between the first conversion module and the second conversion module can be calculated as:

[0210]

[0211]

[0212] In the formula, α1 represents the voltage distribution ratio of the first conversion module, and α2 represents the voltage distribution ratio of the second conversion module.

[0213] Step S1846: Determine a first target output voltage of the first conversion module and a second target output voltage of the second conversion module based on the voltage allocation ratio and the voltage difference.

[0214] This implementation method has significant beneficial effects by determining the available voltage adjustment range of the energy storage module and the photovoltaic module under the current operating conditions, calculating the distribution ratio of the voltage difference, and determining the target output voltage of the first conversion module and the second conversion module based on this. First, the method dynamically adjusts the voltage distribution ratio according to the actual operating capacity of the first conversion module and the second conversion module, making full use of the adjustment potential of the energy storage module and the photovoltaic module to avoid resource waste and overload. Secondly, by considering the available voltage adjustment range, the accuracy of the distribution ratio is improved, making the adjustment process more efficient and stable. In addition, this method can adapt to the real-time changes in the remaining capacity of the energy storage module and the output power of the photovoltaic module, realize flexible inter-module collaboration, and optimize the efficiency of electric energy utilization. Finally, this method ensures that the bus voltage can be stably increased to the target value under dynamic loads and complex environments, improves the reliability and adjustment efficiency of operation, and prolongs the service life.

[0215] In some implementations, the step of generating a first control signal based on the first target output voltage and generating a second control signal based on the second target output voltage includes:

[0216] Step S1861: in the initial boost phase, based on the first target output voltage and the second target output voltage, respectively determining the initial duty cycles of the first conversion module and the second conversion module;

[0217] In this embodiment, the initial voltage boosting stage may be represented as a stage of rapidly increasing the bus voltage, for example, a stage of increasing the current bus voltage to 95% of a preset value.

[0218] In this embodiment, the controller can determine the initial duty cycle of the first conversion module and the second conversion module respectively based on the feedforward control and the first target output voltage and the second target output voltage in the initial boost stage. The feedforward control can be expressed as generating the initial duty cycle based only on the first target output voltage and the second target output voltage and the current bus voltage without considering the error.

[0219] Step S1862: According to the initial duty cycle, initial control signals of the first conversion module and the second conversion module are generated respectively and sent to the first conversion module and the second conversion module to control the first conversion module and the second conversion module to perform a boost operation.

[0220] Step S1863: After the initial boost phase is completed, the error data between the current bus voltage data and the preset value is determined.

[0221] Step S1864: Based on the error data, dynamically adjust the initial duty cycles of the first conversion module and the second conversion module to obtain a corrected duty cycle.

[0222] In this implementation, the controller may dynamically adjust the initial duty cycles of the first conversion module and the second conversion module based on the error data and PID control to obtain a corrected duty cycle.

[0223] In this implementation, the controller may dynamically adjust the initial duty cycles of the first conversion module and the second conversion module based on the error data and the sliding mode control to obtain a corrected duty cycle.

[0224] Step S1865: According to the corrected duty cycle, respectively generate correction control signals of the first conversion module and the second conversion module and send them to the first conversion module and the second conversion module to stabilize the bus voltage data to a preset value.

[0225] This implementation method dynamically adjusts the duty cycle of the first conversion module and the second conversion module in the combination of the initial boost stage and the fine adjustment stage to achieve stable control of the bus voltage. Specifically, first, the initial duty cycle is quickly determined using feedforward control in the initial boost stage, which effectively shortens the response time of the bus voltage from the initial state to a value close to the preset value, and improves the rapidity and efficiency of the energy storage system. Secondly, after the initial boost stage, the duty cycle is dynamically adjusted in combination with real-time error data to enter the fine adjustment stage, which can effectively eliminate errors and avoid overshoot and oscillation, thereby improving the accuracy and stability of bus voltage regulation. In addition, this two-stage control strategy makes full use of the rapidity of feedforward control and the accuracy of closed-loop control, achieves a balance between regulation speed and regulation accuracy, and ensures the reliability and efficient operation of the energy storage system under dynamic loads and complex environments. Finally, by generating the initial and revised control signals in steps, the smooth transition of the regulation process is guaranteed, the risk of incoordination between modules is reduced, and the service life of the system equipment is extended.

[0226] According to an embodiment of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a computer, the computer executes the method described in any of the above embodiments.

[0227] According to an embodiment of the present invention, a computer program product including instructions is also provided. When the instructions are executed by a computer, the computer executes a method in any one of the above embodiments.

[0228] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0229] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0230] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0231] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0232] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An energy storage system, comprising an energy storage module and a photovoltaic module, characterized in that: The system further comprises: A first conversion module, one end of which is connected to the busbar, and the other end of which is connected to the energy storage module; wherein the first conversion module is a module for performing a voltage boost process on the output voltage of the energy storage module; A second conversion module, one end of which is connected to the busbar, and the other end of which is connected to the photovoltaic module; wherein the second conversion module is a module for performing a voltage boost process on the output voltage of the photovoltaic module; The controller, when detecting that the energy storage system switches to off-grid operation, obtains the bus voltage data of the energy storage system, controls the first conversion module to adjust the bus voltage data to try to increase the bus voltage data to a preset value, and then determines whether to control the second conversion module to adjust the bus voltage data. If the determination is yes, the controller controls the first conversion module and the second conversion module to jointly increase the bus voltage data to the preset value.

2. The system according to claim 1, characterized in that The system further comprises: A voltage acquisition module, one end of which is connected to the controller signal, and the other end of which is connected to the bus, and is connected between one end of the first conversion module and one end of the second conversion module.

3. The system according to claim 1, characterized in that The system further comprises: A switch module is arranged between the photovoltaic module and the second conversion module.

4. A control method for an energy storage system, characterized in that: The energy storage system comprises at least an energy storage module, a photovoltaic module, a first conversion module connected to the energy storage module, and a second conversion module connected to the photovoltaic module; the method comprises: When it is detected that the energy storage system is switched to off-grid operation, the bus voltage data of the energy storage system is obtained; Controlling the first conversion module to adjust the bus voltage data to try to increase the bus voltage data to a preset value; wherein the first conversion module is a module for performing a voltage boost process on the output voltage of the energy storage module; Determine whether to control the second conversion module to adjust the bus voltage data; wherein the second conversion module is a module for performing a voltage boost process on the output voltage of the photovoltaic module; If the judgment is yes, the first conversion module and the second conversion module are controlled to jointly increase the bus voltage data to a preset value.

5. The method according to claim 4, characterized in that The step of determining whether to control the second conversion module to adjust the bus voltage data includes: Based on a preset judgment rule and the bus voltage data adjusted by the first conversion module, it is determined whether to control the second conversion module to adjust the bus voltage data.

6. The method according to claim 4, characterized in that The step of judging whether to control the second conversion module to adjust the bus voltage data based on the preset judgment rule and the bus voltage data adjusted by the first conversion module includes: Re-acquire the bus voltage data of the energy storage system multiple times; Determine whether the re-acquired bus voltage data is less than a preset value; If the judgment is yes, the count number is increased; wherein the count number is the number of times that the bus voltage data does not reach the preset value; Determine whether the current count number is greater than or equal to the count threshold; When the counted number is greater than or equal to the number threshold, it is determined that the second conversion module needs to be controlled to adjust the bus voltage data.

7. The method according to claim 4, characterized in that The step of judging whether to control the second conversion module to adjust the bus voltage data based on the preset judgment rule and the bus voltage data adjusted by the first conversion module includes: Re-acquire the bus voltage data of the energy storage system multiple times within a preset time window; Calculate the average value of the bus voltage data within the preset time window; Determining that the average value reaches a preset value; When the average value reaches a preset value, it is determined that the second conversion module needs to be controlled to adjust the bus voltage data.

8. The method according to claim 4, characterized in that The step of controlling the first conversion module and the second conversion module to jointly increase the bus voltage data to a preset value includes: Calculate the voltage difference between the current bus voltage data and the preset value; Based on the voltage difference, determining a first target output voltage of the first conversion module and a second target output voltage of the second conversion module respectively; generating a first control signal based on the first target output voltage and generating a second control signal based on the second target output voltage; The first control signal is sent to the first conversion module and the second control signal is sent to the second conversion module to adjust the output voltages of the first conversion module and the second conversion module.

9. The method according to claim 8, characterized in that The step of respectively determining a first target output voltage of the first conversion module and a second target output voltage of the second conversion module based on the voltage difference comprises: Determining an available voltage regulation range of the energy storage module and the photovoltaic module under current operating conditions; Based on the available voltage adjustment range, calculating a voltage distribution ratio of the voltage difference between the first conversion module and the second conversion module; Based on the voltage distribution ratio and the voltage difference, a first target output voltage of the first conversion module and a second target output voltage of the second conversion module are determined.

10. The method according to claim 8, characterized in that The step of generating a first control signal based on the first target output voltage and generating a second control signal based on the second target output voltage comprises: In the initial boost phase, based on the first target output voltage and the second target output voltage, initial duty cycles of the first conversion module and the second conversion module are determined respectively; According to the initial duty cycle, initial control signals of the first conversion module and the second conversion module are generated respectively and sent to the first conversion module and the second conversion module to control the first conversion module and the second conversion module to perform a boost operation; After the initial boost phase is over, determining the error data between the current bus voltage data and the preset value; Based on the error data, dynamically adjusting the initial duty cycle of the first conversion module and the second conversion module to obtain a corrected duty cycle; According to the modified duty cycle, modified control signals of the first conversion module and the second conversion module are generated and sent to the first conversion module and the second conversion module, so as to stabilize the bus voltage data to a preset value.

Images