A control method, device and equipment of a cascade H-bridge energy storage system and a storage medium

Abstract

The application provides a kind of cascade H bridge energy storage system control method, device, equipment and storage medium, applied to including multiple H bridge units of energy storage system, each H bridge unit is connected with independent group of battery unit, method includes: periodically obtaining the battery voltage of each battery unit and sorting;Real-time acquisition target voltage instantaneous value of system output;According to the current working state of energy storage system, battery voltage sorting result and the target voltage instantaneous value, dynamically adjust the required enabled battery unit and its corresponding H bridge unit;For each H bridge unit enabled, control its working mode is always open mode or pulse width modulation mode, wherein, the number of H bridge unit in pulse width modulation mode is 1;For each H bridge unit not enabled, control its working mode is always off mode.The application can achieve the comprehensive beneficial effects of high efficiency, long life and high output power quality synchronously without increasing the hardware complexity.

Description

Technical Field

[0001] This application relates to the field of power electronics, and more specifically, to a control method, apparatus, and equipment for a cascaded H-bridge energy storage system. Background Technology

[0002] Cascaded H-bridge multilevel inverter technology is one of the most widely used topologies in multilevel inverters. This topology consists of multiple H-bridge power units connected in series. Each H-bridge unit has an independent DC power supply, and its output can generate positive, negative, and zero voltage levels. By connecting the outputs of N such H-bridge units in series, theoretically 2N+1 different output voltage levels can be synthesized. Its basic working principle is to control the combination of output levels from each H-bridge unit to create a stepped wave that approximates a sine wave. This is further enhanced by a modulation strategy that controls the switching timing of each unit's level, making the final total output voltage waveform closely approximate an ideal sine wave. This structure, with its modular design, high output waveform quality, and ease of expansion, occupies an important position in high-voltage, high-capacity applications such as motor drives, new energy grid connection, and reactive power compensation.

[0003] Unipolar frequency-doubled carrier horizontal phase-shift sinusoidal pulse width modulation (PWM) technology is a mainstream modulation method currently used in cascaded H-bridge inverters. While this method can increase the equivalent switching frequency and reduce output harmonics, it still suffers from problems such as excessively high overall switching losses and uneven cell voltages in practical applications, failing to meet usage requirements.

[0004] Therefore, this application provides a control method, apparatus, equipment, and storage medium for a cascaded H-bridge energy storage system to solve one of the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a control method, apparatus, and equipment for a cascaded H-bridge energy storage system, which can solve at least one of the aforementioned technical problems. The specific solution is as follows: According to a specific embodiment of this application, in a first aspect, this application provides a control method for a cascaded H-bridge energy storage system, comprising: An energy storage system comprising multiple H-bridge units, each H-bridge unit connecting to an independent group of battery cells, the method comprising: periodically acquiring and sorting the battery voltage of each battery cell; acquiring the instantaneous value of the target voltage output by the system in real time; dynamically adjusting the battery cells to be activated and their corresponding H-bridge units according to the current operating state of the energy storage system, the battery voltage sorting result and the instantaneous value of the target voltage; for each activated H-bridge unit, controlling its operating mode to normally open mode or pulse width modulation mode, wherein the number of H-bridge units in pulse width modulation mode is 1; for each inactive H-bridge unit, controlling its operating mode to normally off mode.

[0006] In one embodiment, the step of dynamically adjusting the battery cells to be activated and their corresponding H-bridge cells according to the current operating state of the energy storage system, the battery voltage sorting result, and the instantaneous value of the target voltage includes: when the operating state of the energy storage system is the discharge state, activating each battery cell in sequence according to the battery voltage from high to low.

[0007] In one embodiment, the step of dynamically adjusting the battery cells to be activated and their corresponding H-bridge cells according to the current operating state of the energy storage system, the battery voltage sorting result, and the instantaneous value of the target voltage includes: when the operating state of the energy storage system is charging, activating each battery cell sequentially in order of battery voltage from low to high.

[0008] In one implementation, battery voltage monitoring is performed on the currently active n groups of battery cells; in response to No adjustment is made to the number of activated battery cells; in response to According to the aforementioned sequence, a new set of battery cells and their corresponding H-bridge cells are activated; in response to According to the aforementioned order, the most recently activated group of battery cells and its corresponding H-bridge cells are deactivated; wherein, S is the instantaneous value of the target voltage. n S represents the battery voltage and value of the currently active n battery cells. n-1 This represents the battery voltage and value of the first n-1 battery cells currently in use.

[0009] In one implementation, controlling the operating mode of each activated H-bridge unit to be either normally open or pulse width modulation includes: responding to The nth H-bridge unit is in pulse width modulation mode, and the first n-1 H-bridge units are all in normally open mode.

[0010] In one implementation, the nth H-bridge unit is in pulse width modulation mode, and its duty cycle is calculated as follows: Where duty is the duty cycle of the nth battery cell group; S is the instantaneous value of the target voltage. n-1 E represents the battery voltage and value of the first n-1 currently active battery cells. n Let t be the battery voltage of the nth battery cell, and t be the current time.

[0011] In one embodiment, when the energy storage system is in grid-connected state, the instantaneous value of the target voltage is calculated in the following manner: Among them, U grid This is the effective value of the grid voltage. f grid t represents the power grid frequency and t represents time.

[0012] In one embodiment, when the energy storage system is in an off-grid state, the instantaneous value of the target voltage is calculated in the following manner: Where U0 is the rated output voltage, f rated The system's rated frequency is t, where t is time.

[0013] According to a specific embodiment of this application, in a second aspect, this application provides a cascaded H-bridge energy storage system control device, applied to an energy storage system including multiple H-bridge units, each H-bridge unit being connected to an independent group of battery units, comprising: a sorting module configured to periodically acquire and sort the battery voltage of each battery unit; an acquisition module configured to acquire the instantaneous value of the target voltage output by the system in real time; an adjustment module configured to dynamically adjust the battery units to be activated and their corresponding H-bridge units according to the current operating state of the energy storage system, the battery voltage sorting result, and the instantaneous value of the target voltage; and a control module configured to control the operating mode of each activated H-bridge unit to be normally open or pulse width modulation mode, wherein the number of H-bridge units in pulse width modulation mode is 1; and to control the operating mode of each inactive H-bridge unit to be normally off.

[0014] According to a specific embodiment of this application, in a third aspect, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the method described in any one of the first aspects.

[0015] According to a specific embodiment of this application, in a fourth aspect, this application provides a computer-readable storage medium having a computer program / instructions stored thereon, which, when executed by a processor, implements the method described in any one of the first aspects.

[0016] Compared with the prior art, the above-described solution of this application has at least the following beneficial effects: This application provides a control method for a cascaded H-bridge energy storage system. Based on the current operating state of the energy storage system, the battery voltage ranking results of each battery cell, and the instantaneous value of the target voltage, the method dynamically adjusts the battery cells to be activated and their corresponding H-bridge cells. It also controls that only one set of each activated H-bridge cell is in pulse width modulation (PWM) mode, while the rest are in normally open mode. By maintaining most activated H-bridge cells in a normally open mode with no switching losses, the number of switching transistors performing high-frequency switching operations at the same time is significantly reduced, thereby greatly reducing the overall switching losses of the system and improving system efficiency. Simultaneously, high-frequency PWM modulation is performed using only a single cell, ensuring the quality of the output voltage waveform. Furthermore, the system can adaptively select the most suitable battery cell for operation, naturally achieving active balancing between battery cells (cells) during charging and discharging, effectively improving battery cell consistency, energy utilization, and cycle life. Without increasing hardware complexity, it simultaneously achieves the comprehensive benefits of high efficiency, long lifespan, and high output power quality. Attached Figure Description

[0017] Figure 1 A topology of a cascaded H-bridge energy storage system is shown; Figure 2 A flowchart of a control method for a cascaded H-bridge energy storage system is shown; Figure 3 A schematic diagram of a process for dynamically adjusting the number of battery cells is shown; Figure 4 A waveform diagram of an output sine wave is shown; Figure 5 A unit block diagram of a control device for a cascaded H-bridge energy storage system according to an embodiment of this application is shown; Figure 6 This is a block diagram of an electronic device for controlling a cascaded H-bridge energy storage system, according to an exemplary embodiment. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0020] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0021] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0022] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0023] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0024] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0025] Unipolar frequency-doubled carrier horizontal phase-shift sinusoidal pulse width modulation (PWM) is a mainstream modulation method currently used in cascaded H-bridge inverters. This method uses a sinusoidal modulating wave compared with multiple triangular carriers to generate a switching signal. Specifically, for a single-phase system composed of N H-bridge units, 2N triangular carriers with the same amplitude but sequentially staggered phases are required. The two triangular carriers used in the upper and lower arms of the same H-bridge unit are 180 degrees out of phase, while the carrier phases of corresponding arms of adjacent H-bridge units in the same phase are sequentially staggered by 180 degrees / N phase angles. This carrier phase-shifting method effectively increases the equivalent switching frequency and reduces output harmonics.

[0026] However, the existing full-cell high-frequency modulation strategy has significant drawbacks. First, because the circuit topology itself contains a large number of switching devices, and the modulation strategy requires each H-bridge unit to operate at high frequency continuously throughout the entire power frequency cycle, the overall switching losses of the system are very high, limiting further improvements in system efficiency. Second, in practical applications, although the cells connected to different H-bridge units theoretically have the same usage time, individual differences among the cells and inconsistencies in their operating environments can lead to voltage imbalances among the cells. Current technology lacks an effective active balancing mechanism to address this inconsistency during operation. Long-term operation will exacerbate the differences between cells, thereby shortening the lifespan of the entire battery system and leading to capacity waste and safety risks.

[0027] In view of this, this application provides a control method for a cascaded H-bridge energy storage system to solve the above problems.

[0028] The optional embodiments of this application are described in detail below with reference to the accompanying drawings.

[0029] The embodiments provided in this application are embodiments of a control method for a cascaded H-bridge energy storage system.

[0030] The following is combined with Figure 1 The embodiments of this application will be described in detail.

[0031] Figure 1 The topology of a cascaded H-bridge energy storage system is shown, which includes multiple H-bridge units, each of which consists of four switching transistors S. i1 -S i4 Composed of (such as IGBT or MOSFET), where S i1 and S i2 Composed of the left bridge arm switching transistor, S i3 and S i4The right bridge arm switching transistor is formed, and its DC side is connected to battery unit E. Battery unit E includes, but is not limited to, a cell group (composed of multiple cells) or a battery pack (composed of multiple cell groups). The AC outputs of multiple H-bridge units are cascaded, with the midpoint of the left arm of the i-th H-bridge unit connected to the midpoint of the right arm of the (i+1)-th H-bridge unit, and the midpoint of the right arm of the i-th H-bridge unit connected to the midpoint of the left arm of the (i-1)-th H-bridge unit. Each H-bridge unit can output three levels: +Vdc (S... i1 and S i4 -Vdc (S) i2 and S i3 (conduction) and 0 (S) i1 and S i3 On, or S i2 and S i4 (Conduction). The modular structure and flexible control strategy of the cascaded H-bridge topology enable the system to possess strong fault tolerance and maintainability. When a unit needs to be removed, the unit is electrically short-circuited by controlling the switching transistor, causing its output voltage to be zero. When a unit needs to be added, that unit is re-involved in the system's PWM modulation, outputting the required level.

[0032] In this embodiment of the application, based on the topology of the cascaded H-bridge energy storage system described above, a control method for the cascaded H-bridge energy storage system is also provided. This method can significantly reduce the overall switching loss of the system, improve system efficiency, and help to slow down the expansion trend of capacity deviation between cells and improve cell consistency.

[0033] Figure 2 A flowchart of a control method for a cascaded H-bridge energy storage system is shown, including the following steps S101 to S104.

[0034] Step S101: Periodically acquire the battery voltage of each battery cell and sort them.

[0035] The sorting rules can be either from high to low or from low to high.

[0036] Step S102: Obtain the instantaneous value of the target voltage output by the system in real time.

[0037] For example Figure 1 The instantaneous target voltage value obtained for the system shown will vary depending on whether the system is connected to or disconnected from the grid.

[0038] 1) When the energy storage system is in grid-connected mode, it essentially operates as a controlled current source. At this time, the voltage amplitude, frequency, and waveform at the system connection point are determined by the dynamic balance of power generation and load across the entire power grid. The output voltage of the energy storage system is strictly "clamped" by the powerful grid voltage. Therefore, in terms of control logic, the system uses circuits such as phase-locked loops (PLLs) to obtain the instantaneous value of the target voltage in real time, and uses this as a reference for synchronization and control, ensuring that the instantaneous value of its AC-side output voltage remains synchronized with the instantaneous value of the grid voltage.

[0039] Under grid-connected conditions, the instantaneous value of the target voltage is calculated as follows:

[0040] Among them, U grid This is the effective value of the grid voltage. f grid Let θ be the grid frequency, t be time, and θ1 be the first initial phase angle.

[0041] 2) When the energy storage system is off-grid, it will act as an independent voltage source, relying on its internal controller to actively establish and maintain a stable AC bus voltage. The controller actively generates the instantaneous value of the target voltage based on the preset rated voltage and rated frequency.

[0042] In the off-grid state, the instantaneous value of the target voltage is calculated as follows:

[0043] Among them, U rated The rated voltage set for the system, f rated The system's rated frequency is given by t, time is given by t, and the second initial phase angle is given by θ2.

[0044] Step S103: Based on the current operating state of the energy storage system, the battery voltage sorting results, and the instantaneous value of the target voltage, dynamically adjust the battery cells to be activated and their corresponding H-bridge cells.

[0045] The energy storage system operates in several states, including charging, discharging, and standby. When the system is in a discharging state, each battery cell is activated sequentially from highest to lowest voltage. When the system is in a charging state, each battery cell is activated sequentially from lowest to highest voltage.

[0046] This battery cell activation strategy, based on system charge / discharge states and battery voltage sequencing, encourages fully charged cells to release more energy during discharge, while depleted cells absorb more energy during charging. This process helps mitigate voltage inconsistencies among battery cells, thereby extending the overall battery system lifespan.

[0047] The number of activated battery cells and their corresponding H-bridge cells is dynamically adjusted based on the following conditions: like No adjustment will be made to the number of enabled battery cells and their corresponding H-bridge cells; like According to the order described above, a new set of battery cells and their corresponding H-bridge cells are activated. like Based on the order described above, the most recently enabled group of battery cells and its corresponding H-bridge cells will be disabled.

[0048] The above S is the instantaneous value of the target voltage. n S represents the battery voltage and value of the currently active n battery cells. n-1 This represents the battery voltage and value of the first n-1 battery cells currently in use.

[0049] Step S104: For each enabled H-bridge unit, control its operating mode to normally open mode or pulse width modulation mode, wherein the number of H-bridge units in pulse width modulation mode is 1; for each disabled H-bridge unit, control its operating mode to normally off mode.

[0050] Through the dynamic adjustment in step S103 above, the number of activated battery cells is controlled within a certain range. Within the specified range, for the n groups of H-bridge units that are enabled, the last group (i.e., the nth group) of H-bridge units is controlled in pulse width modulation mode, while the other groups (from the 1st group to the (n-1th group) of H-bridge units are controlled in normally open mode. For each H-bridge unit that is not enabled, its operating mode is controlled in normally off mode.

[0051] Normally Open Mode: During a certain period of the power frequency cycle, the corresponding switch of this H-bridge unit remains on (e.g., if a positive output level is required, then S...). i1 and S i4 Continuously on; if a negative output level is required, then S i2 and S i3 (Continuously on) without performing any high-frequency switching action, which is equivalent to outputting a fixed DC level (+Vdc or -Vdc) to the unit during this period.

[0052] Pulse Width Modulation (PWM) Mode: During a certain period of the power frequency cycle, the corresponding switching transistor of this H-bridge unit needs to be repeatedly turned on and off according to the PWM modulation rule within the high-frequency modulation cycle (carrier cycle), i.e., pulse width modulation is performed. The average voltage of the unit's output is adjusted by changing the duty cycle. For example, if the duty cycle is 0.2 and a positive output level is required, then S... i1 and S i4 Synchronous conduction 0.2*T sw (where T) sw (for modulation period), S i2 and S i3 Turn off, then turn off the two upper bridge arms (S) i1 and S i3 ) or two lower arms (S i2 and S i4 Synchronous conduction 0.8*T sw For example, if the duty cycle is 0.5 and a negative output level is required, then S... i2 and S i3 Synchronous conduction 0.5*T sw S i1 and S i4 Shut down; then the two upper bridge arms (S) i1 and S i3 ) or two lower arms (S i2 and S i4 Synchronous conduction 0.5*T sw .

[0053] Normally Off Mode: During a certain period of the power frequency cycle, the corresponding switch of this H-bridge unit remains off (e.g., S). i1 and S i3 On, S i2 and S i4 Off; or S i1 and S i3 Off, S i2 and S i4 (Conduction) is equivalent to the unit not outputting an effective level during this period, and the output level is 0.

[0054] For H-bridge units in pulse width modulation mode, their duty cycle is calculated as follows:

[0055] Where duty is the duty cycle of the nth group of battery cells. S is the instantaneous value of the target voltage. n-1 E represents the battery voltage and value of the first n-1 currently active battery cells. n Let t be the battery voltage of the nth battery cell, and t be the current time.

[0056] In this embodiment, by maintaining most of the enabled H-bridge units in a normally-on mode with no switching losses, the number of switching transistors performing high-frequency switching operations simultaneously is significantly reduced, thereby greatly reducing the overall switching losses of the system and improving system efficiency. Simultaneously, high-frequency PWM modulation is performed using only a single unit, ensuring the quality of the output voltage waveform. Furthermore, through voltage sequencing and the logic of differentially enabling battery units during charging and discharging, an active balancing mechanism is naturally embedded, allowing high-voltage battery units to discharge more and low-voltage battery units to charge more, effectively suppressing inconsistencies between cells and improving the usable capacity and cycle life of the battery units. This application achieves a comprehensive benefit of high efficiency, long lifespan, and high output power quality simultaneously through pure control methods without changing the hardware topology.

[0057] Figure 3 A schematic diagram of a process for dynamically adjusting the number of battery cells and controlling the corresponding H-bridge cells is shown.

[0058] In some embodiments, such as Figure 3 As shown, a specific implementation method for controlling a cascaded H-bridge energy storage system is provided. This embodiment first calculates the sum of the voltages of the first n-1 battery groups (Sn-1) and the total sum of battery voltages (Sn) among the currently activated n battery groups, and then obtains the instantaneous target voltage value output by the current system. Next, based on Based on the comparison results with Sn and Sn-1, the activation status of the battery cells is dynamically adjusted: if it is determined that the number of currently activated battery cells is excessive, the last activated battery cell is deactivated; if it is determined that the number of currently activated battery cells is insufficient, a new group of battery cells is activated from the inactive battery cells according to the order of battery voltage from low to high (charging state) and from high to low (discharging state). After the battery cell quantity adjustment is completed, the working state of the H-bridge unit corresponding to each battery cell is controlled. The H-bridge unit corresponding to the last activated group of battery cells outputs a PWM wave, i.e., it is in a high-frequency switching state, while the H-bridge units corresponding to the other activated battery cells remain in a normally open state; the H-bridge units corresponding to the inactive battery cells remain in a normally closed state. Through the above process, the number of battery cells deployed is dynamically optimized based on the real-time target voltage, and the working modes of each H-bridge unit are coordinated to reduce switching losses and improve system efficiency. At the same time, active balancing between battery cells is achieved, effectively alleviating the problem of cell inconsistency and extending the overall lifespan of the battery system. In addition, using only a single H-bridge unit for high-frequency PWM modulation ensures that the output waveform can still maintain a high-quality low-harmonic sine wave during multi-level switching. Ultimately, without increasing hardware complexity, a comprehensive beneficial effect of high efficiency, long lifespan, and high output power quality is achieved simultaneously.

[0059] For ease of understanding, a specific embodiment is shown below. Figure 4 A waveform diagram of an output sine wave is shown.

[0060] The cascaded H-bridge energy storage system has 5 battery units and corresponding H-bridge units. The system is currently in an off-grid discharge state. The rated voltage of the system is set to 205V (the peak voltage in the figure is 290V), and the rated frequency is f = 50. The battery units are arranged in descending order of battery voltage as follows: E1=100V, E2=100V, E3=95V, E4=80V, and E5=76V.

[0061] First, calculate the sum of the voltages of the first n battery cells: S1 = E1 = 100V, S2 = E1 + E2 = 200V, S3 = E1 + E2 + E3 = 295V, S4 = E1 + E2 + E3 + E4 = 375V, S5 = E1 + E2 + E3 + E4 + E5 = 451V. According to the target requirement, a sine wave waveform needs to be output, and the peak voltage of this waveform is... Therefore, it can be seen that only the first three battery units (E1, E2 and E3) need to be turned on to meet the requirements of one power frequency cycle. The last two battery units, E4 and E5, are not turned on, and their corresponding H-bridge units remain in the normally off mode.

[0062] When the first three battery cells are activated in a power frequency cycle, the boundary point marked in the waveform is at time [time value missing]. Figure 4 The values ​​t1 to t4 are shown. The rated voltage of the output sine wave is U. rated The frequency is f, and the angular frequency is... The period is T.

[0063] Next, determine the time period boundary points. Divide half a cycle of the output sine wave (T / 2 in this example) into 5 time periods. The boundary points to be calculated include t1, t2, t3, and t4, which are obtained using the following formula:

[0064] Then, control the operating status of the H-bridge unit corresponding to each group of enabled battery units.

[0065] The instantaneous value of the target voltage output by the system during the time period [0, t1]. Therefore, only the first group of battery cells needs to be turned on, and its corresponding H-bridge cell is in a high-frequency switching state with a duty cycle of Other battery cells are not turned on, and their corresponding H-bridge cells are in a normally off state.

[0066] The instantaneous value of the target voltage output by the system within the time interval (t1, t2]. Therefore, it is necessary to turn on the first and second battery groups. The H-bridge unit corresponding to the first group is in a normally open state, and the H-bridge unit corresponding to the second group is in a high-frequency switching state with a duty cycle of [missing information]. Other battery cells are not turned on, and their corresponding H-bridge cells are in a normally off state.

[0067] The instantaneous value of the target voltage output by the system within the time period (t2, t3]. Therefore, it is necessary to turn on the battery cells from group 1 to group 3. The H-bridge cells corresponding to groups 1 and 2 are in the normally open state, while the H-bridge cells corresponding to group 3 are in the high-frequency switching state, with a duty cycle of Other battery cells are not turned on, and their corresponding H-bridge cells are in a normally off state.

[0068] The instantaneous value of the target voltage output by the system within the time period (t3, t4]. Therefore, it is necessary to turn on the first and second battery groups. The H-bridge unit corresponding to the first group is in a normally open state, and the H-bridge unit corresponding to the second group is in a high-frequency switching state, with a duty cycle of Other battery cells are not turned on, and their corresponding H-bridge cells are in a normally off state.

[0069] Within the time period (t4, T / 2], the instantaneous value of the target voltage output by the system Therefore, only the first group of battery cells needs to be turned on, and its corresponding H-bridge cell is in a high-frequency switching state with a duty cycle of [missing information]. Other battery cells are not turned on, and their corresponding H-bridge cells are in a normally off state.

[0070] Within the time interval [0, T / 2], the instantaneous value of the target voltage output by the system Therefore, the S of the H-bridge unit in normally open mode i1 and S i4 The switch remains on, and the S of the H-bridge unit in pulse width modulation mode... i1 and S i4 Synchronous conduction duty cycle time.

[0071] Similarly, the operating status of the activated battery unit and the corresponding H-bridge unit within the time period [T / 2, T] can also be obtained using the above method. However, it should be noted that the instantaneous value of the target voltage output by the system within this time period is important. Therefore, the S of the H-bridge unit in normally open mode i2 and S i3 The switch remains on, and the S of the H-bridge unit in pulse width modulation mode... i2 and S i3 Synchronous conduction duty cycle time.

[0072] This application also provides apparatus embodiments that follow the above embodiments, for implementing the method steps described in the above embodiments. The interpretation of the same names is the same as that in the above embodiments, and they have the same technical effects as those in the above embodiments, so they will not be repeated here.

[0073] like Figure 5 As shown, this application provides a cascaded H-bridge energy storage system control device 500, applied to an energy storage system including multiple H-bridge units, each H-bridge unit being connected to an independent group of battery cells, including: The sorting module 501 is configured to periodically acquire the battery voltage of each battery cell and sort it.

[0074] The acquisition module 502 is configured to acquire the instantaneous value of the target voltage output by the system in real time.

[0075] The adjustment module 503 is configured to dynamically adjust the battery cells to be activated and their corresponding H-bridge cells based on the current operating state of the energy storage system, the battery voltage sorting results, and the instantaneous value of the target voltage.

[0076] The control module 504 is configured to control the operating mode of each enabled H-bridge unit to be either normally open or pulse width modulation mode, wherein the number of H-bridge units in pulse width modulation mode is 1; and to control the operating mode of each disabled H-bridge unit to be normally off.

[0077] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0078] Figure 6 This is a block diagram of an electronic device 600 for controlling a cascaded H-bridge energy storage system, according to an exemplary embodiment.

[0079] like Figure 6 As shown, one embodiment of this application provides an electronic device 600. The electronic device 600 includes a memory 601, a processor 602, and an input / output (I / O) interface 603. The memory 601 is used to store instructions. The processor 602 is used to execute the cascaded H-bridge energy storage system control method of this application embodiment by calling the instructions stored in the memory 601. The processor 602 is connected to both the memory 601 and the I / O interface 603, for example, via a bus system and / or other forms of connection mechanisms (not shown). The memory 601 can be used to store programs and data, including the program for the cascaded H-bridge energy storage system control method involved in the embodiments of this application. The processor 602 executes various functional applications and data processing of the electronic device 600 by running the program stored in the memory 601.

[0080] In this embodiment, the processor 602 can be implemented using at least one of the following hardware forms: digital signal processor (DSP), field programmable gate array (FPGA), and programmable logic array (PLA). The processor 602 can be one or a combination of several of the following: central processing unit (CPU) or other processing units with data processing capability and / or instruction execution capability.

[0081] The memory 601 in this embodiment may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), flash memory, hard disk drive (HDD), or solid state drive (SSD).

[0082] In this embodiment, the I / O interface 603 can be used to receive input instructions (such as numeric or character information, and to generate key signal inputs related to user settings and function control of the electronic device 500), and can also output various information (such as images or sounds) to the outside. In this embodiment, the I / O interface 603 may include one or more of the following: a physical keyboard, function keys (such as volume control keys, power buttons, etc.), a mouse, a joystick, a trackball, a microphone, a speaker, and a touch panel.

[0083] In some embodiments, this application provides a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, perform any of the methods described above.

[0084] In some embodiments, this application provides a computer program product comprising a computer program that, when executed by a processor, performs any of the methods described above.

[0085] Although the operations are described in a specific order in the accompanying drawings, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all of the operations shown to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0086] The methods, apparatus, devices, and storage media of this application can be implemented using standard programming techniques, and various method steps can be implemented using rule-based logic or other logic. It should also be noted that the terms "apparatus" and "module" as used herein and in the claims are intended to include implementations using one or more lines of software code and / or hardware implementations and / or devices for receiving input.

[0087] Any step, operation, or procedure described herein may be performed or implemented using one or more hardware or software modules, either alone or in combination with other devices. In one embodiment, the software module is implemented using a computer program product comprising a computer-readable medium containing computer program code, which is executable by a computer processor to perform any or all of the described steps, operations, or procedures.

[0088] The foregoing description of implementations of this application has been provided for illustrative and descriptive purposes. The foregoing description is not exhaustive and is not intended to limit this application to the exact forms disclosed. Various modifications and variations may exist in accordance with the foregoing teachings, or may arise from practice of this application. These embodiments were chosen and described to illustrate the principles of this application and its practical application, enabling those skilled in the art to utilize this application in various implementations and modifications to suit the specific purpose of the concept.

[0089] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0090] It can be further understood that, unless otherwise specified, "connection" includes both direct connections where no other components exist between the two parties and indirect connections where other components exist between them.

[0091] It is further understood that although the operations are described in a specific order in the accompanying drawings in the embodiments of this application, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all the operations shown to be performed to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0092] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the field of this application that are not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0093] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

[0094] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A control method of a cascaded H-bridge energy storage system, characterized in that, The method, applicable to an energy storage system comprising multiple H-bridge units, each H-bridge unit connected to an independent group of battery cells, includes: The battery voltage of each battery cell is periodically acquired and sorted. Real-time acquisition of the instantaneous value of the target voltage output by the system; Based on the current operating status of the energy storage system, the battery voltage sorting results, and the instantaneous value of the target voltage, the required activated battery cells and their corresponding H-bridge cells are dynamically adjusted. When the energy storage system is in the discharge state, each group of battery cells is activated sequentially according to the battery voltage from high to low. When the energy storage system is in the charging state, each group of battery cells is activated in sequence according to the battery voltage from low to high. Monitor the battery voltage of the currently active n battery cells; In response to No adjustment will be made to the number of enabled battery cells and their corresponding H-bridge cells; In response to According to the aforementioned sequence, a new set of battery cells and their corresponding H-bridge cells are activated; In response to According to the aforementioned order, the most recently enabled group of battery cells and its corresponding H-bridge cells will be disabled. in, S is the instantaneous value of the target voltage. n S represents the battery voltage and value of the currently active n battery cells. n-1 The battery voltage and value of the first n-1 currently active battery cells; For each activated H-bridge unit, its operating mode is controlled to be either normally open or pulse width modulation mode. The number of H-bridge units in pulse width modulation mode is 1, and the H-bridge units in pulse width modulation mode are determined to be the last group activated according to the sorting result based on the dynamic adjustment. For each H-bridge unit that is not in use, control its operating mode to normally off mode.

2. The method according to claim 1, characterized in that, For each activated H-bridge unit, control its operating mode to either normally open mode or pulse width modulation mode, including: In response to The nth H-bridge unit is in pulse width modulation mode, and the first n-1 H-bridge units are all in normally open mode.

3. The method according to claim 2, characterized in that, The duty cycle of the nth H-bridge unit in pulse width modulation mode is calculated as follows: ； Where duty is the duty cycle of the nth group of battery cells. S is the instantaneous value of the target voltage. n-1 E represents the battery voltage and value of the first n-1 currently active battery cells. n Let t be the battery voltage of the nth battery cell, and t be the current time.

4. The method according to claim 1, characterized in that, When the energy storage system is in grid-connected state, the instantaneous value of the target voltage is calculated in the following manner: ； Among them, U grid This is the effective value of the grid voltage. f grid Let θ be the grid frequency, t be time, and θ1 be the first initial phase angle.

5. The method according to claim 1, characterized in that, When the energy storage system is in an off-grid state, the instantaneous value of the target voltage is calculated in the following manner: ； Among them, U rated The rated voltage set for the system. f rated The system's rated frequency is given by t, time is given by t, and the second initial phase angle is given by θ2.

6. A control device for a cascaded H-bridge energy storage system, characterized in that, For use in energy storage systems comprising multiple H-bridge units, each H-bridge unit connecting to an independent group of battery cells, including: The sorting module is configured to periodically acquire the battery voltage of each battery cell and sort it. The acquisition module is configured to acquire the instantaneous value of the target voltage output by the system in real time; The adjustment module is configured to dynamically adjust the required battery cells and their corresponding H-bridge cells based on the current operating state of the energy storage system, the battery voltage sorting results, and the instantaneous value of the target voltage. When the energy storage system is in the discharge state, each group of battery cells is activated sequentially according to the battery voltage from high to low. When the energy storage system is in the charging state, each group of battery cells is activated in sequence according to the battery voltage from low to high. Monitor the battery voltage of the currently active n battery cells; In response to No adjustment will be made to the number of enabled battery cells and their corresponding H-bridge cells; In response to According to the aforementioned sequence, a new set of battery cells and their corresponding H-bridge cells are activated; In response to According to the aforementioned order, the most recently enabled group of battery cells and its corresponding H-bridge cells will be disabled. in, S is the instantaneous value of the target voltage. n S represents the battery voltage and value of the currently active n battery cells. n-1 The battery voltage and value of the first n-1 currently active battery cells; The control module is configured to control the operating mode of each enabled H-bridge unit to be either normally open or pulse width modulation (PWM) mode, wherein the number of H-bridge units in PWM mode is 1; and to control the operating mode of each disabled H-bridge unit to be normally off.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the method described in any one of claims 1-5.

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