Power grid voltage self-adaptive control method and device of energy storage converter and energy storage converter

Abstract

The invention provides a power grid voltage self-adaptive control method and device for an energy storage converter and the energy storage converter, and relates to the technical field of energy storage converter control, and the method comprises the steps: obtaining the current power grid voltage information; carrying out per-unit processing on the current power grid voltage information based on a preset power grid voltage reference value to obtain a current power grid voltage per-unit value; judging the operation state of the power grid based on the current power grid voltage per unit value; when the operation state of the power grid is a low-voltage state or a high-voltage state, first duration is obtained, and the first duration is duration when the power grid is in the low-voltage state or the high-voltage state; and judging whether the combination of the current power grid voltage per unit value and the first duration meets a preset standard or not, if not, stopping sending waves, and keeping the circuit breaker in a closed state. According to the method provided by the invention, the action times of the circuit breaker can be reduced, the service life of the circuit breaker is prolonged, and the operation stability of a power grid is improved.

Description

[0001] This application is a divisional application. The original application has the application number 202511232740.2 and the invention title of the original application is "Energy Storage Converter Grid Voltage Adaptive Control Method, Device and Energy Storage Converter". The original application date is September 1, 2025. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of energy storage converter control technology, and in particular to an energy storage converter grid voltage adaptive control method, device and energy storage converter. Background Technology

[0003] In energy storage systems, the Power Conversion System (PCS) is a device used to achieve bidirectional energy conversion between the energy storage system and the power grid (and / or load). During grid voltage sags / surges, the PCS can provide reactive power compensation, enabling adaptive control of the grid voltage. The circuit breaker is a crucial component for establishing the electrical connection between the PCS and the grid. However, the frequent opening and closing of the circuit breaker during PCS control presents challenges, including reduced lifespan and potential grid fluctuations that affect grid stability. Summary of the Invention

[0004] This application provides a method, device, and energy storage converter for adaptive grid voltage control, which helps to reduce the number of circuit breaker operations, increase the service life of circuit breakers, and improve the stability of grid operation.

[0005] In a first aspect, this application provides a grid voltage adaptive control method for an energy storage converter, including: Obtain the current grid voltage information; Based on the preset grid voltage reference value, the current grid voltage information is normalized to obtain the current grid voltage per-unit value; The operating status of the power grid is determined based on the current per-unit value of the power grid voltage. The operating status of the power grid is any one of the following: normal operation, low voltage, high voltage, and zero voltage. When the power grid is in low-voltage or high-voltage operation, the first duration is obtained, which is the duration during which the power grid is in low-voltage or high-voltage operation. Determine whether the combination of the current grid voltage per unit value and the first duration meets the preset standard. If not, stop transmitting waves and keep the circuit breaker in the closed state.

[0006] In one possible implementation, the preset standard includes the standard correspondence between the per-unit value of the grid voltage and the normal low-ride-through duration or the normal high-ride-through duration; Determining whether the combination of the current per-unit value of the grid voltage and the first duration meets the preset standard includes: Based on the current per-unit value of the grid voltage and the standard correspondence, determining a second duration, where the second duration is the normal low-ride-through duration or the normal high-ride-through duration corresponding to the current per-unit value of the grid voltage; If the first duration is less than or equal to the second duration, the combination of the current per-unit value of the grid voltage and the first duration meets the preset standard; or If the first duration is greater than the second duration, the combination of the current per-unit value of the grid voltage and the first duration does not meet the preset standard.

[0007] In one possible implementation, the method further includes: When the operating state of the grid is in the high-ride-through state and the combination of the current per-unit value of the grid voltage and the first duration meets the preset standard, absorbing reactive current; or When the operating state of the grid is in the low-ride-through state and the combination of the current per-unit value of the grid voltage and the first duration meets the preset standard, outputting reactive current.

[0008] In one possible implementation, performing per-unit conversion on the current grid voltage information based on a preset grid voltage reference value to obtain the current per-unit value of the grid voltage includes: Performing a preset coordinate conversion and a preset filtering operation on the current grid voltage information to obtain the current positive-sequence d-axis filtering component and the current positive-sequence q-axis filtering component corresponding to the current grid voltage information; Determining the effective value of the current positive-sequence line voltage amplitude based on the current positive-sequence d-axis filtering component and the current positive-sequence q-axis filtering component; Determining the current per-unit value of the grid voltage based on the preset grid voltage reference value and the effective value of the current positive-sequence line voltage amplitude.

[0009] In one possible implementation, determining the operating state of the grid based on the current per-unit value of the grid voltage includes: When A2 < the current per-unit value of the grid voltage ≤ A1, the operating state of the grid is in the high-ride-through state; )]]When A3 ≤ the current per-unit value of the grid voltage ≤ A2, the operating state of the grid is in the normal operating state; When A4 ≤ the current per-unit value of the grid voltage < A3, the operating state of the grid is in the low-ride-through state; When the current per-unit value of the grid voltage < A4, the operating state of the grid is in the zero-ride-through state; Where, A1 > A2 > A3 > A4.

[0010] One possible implementation of the method also includes: When the current grid voltage per unit value is greater than A1, the circuit breaker is disconnected and the machine is shut down.

[0011] One possible implementation of the method also includes: When the power grid is in normal operation, determine the voltage reactive power control status, which is either an enabled state or an disabled state. If the voltage reactive power control state is enabled, the reactive power increment is calculated based on the current grid voltage per unit value and the preset voltage reactive power control rules.

[0012] One possible implementation of the method also includes: When the power grid is in the zero-push-through state, the third duration is obtained, which is the duration during which the power grid is in the zero-push-through state; If the third duration is less than or equal to the normal zero-run-off duration, then the reactive current is output; or If the third duration exceeds the normal zero-break duration, the circuit breaker will be disconnected and the machine will be shut down.

[0013] One possible implementation of the method also includes: If the grid voltage returns to normal after the waveform transmission stops, the waveform transmission will resume and the system will be connected to the grid again.

[0014] Secondly, this application provides an adaptive grid voltage control device for an energy storage converter, comprising: The first acquisition module is used to acquire the current power grid voltage information; The per-unit processing module is used to perform per-unit processing on the current grid voltage information based on the preset grid voltage reference value to obtain the current grid voltage per-unit value; The first judgment module is used to judge the operating status of the power grid based on the current per-unit value of the power grid voltage. The operating status of the power grid is any one of the following: normal operation, low voltage, high voltage and zero voltage. The second acquisition module is used to acquire a first duration when the power grid is in a low-voltage or high-voltage state. The first duration is the duration during which the power grid is in a low-voltage or high-voltage state. The second judgment module is used to determine whether the combination of the current grid voltage per unit value and the first duration meets the preset standard. If it does not meet the standard, the wave transmission is stopped and the circuit breaker is kept in the closed state.

[0015] Thirdly, this application provides an energy storage converter, including: a processor and a memory, wherein the memory is used to store a computer program; and the processor is used to run the computer program to implement the energy storage converter grid voltage adaptive control method as described in the first aspect.

[0016] The beneficial effects of this application are as follows: This application provides a grid voltage adaptive control method, device, and energy storage converter for an energy storage converter. The method involves acquiring the current grid voltage information; normalizing the current grid voltage information based on a preset grid voltage reference value to obtain the current grid voltage per-unit value; determining the grid's operating state based on the current grid voltage per-unit value, where the grid operating state can be any one of normal operation, low-voltage underrunning, high-voltage underrunning, or zero-voltage underrunning; when the grid is in low-voltage or high-voltage underrunning state, acquiring a first duration, which is the duration the grid is in the low-voltage or high-voltage underrunning state; and determining whether the combination of the current grid voltage per-unit value and the first duration meets a preset standard. If not, the signal transmission is stopped, and the circuit breaker remains in the closed state. By judging the grid voltage operating range, under the premise that the current grid voltage exceeds the normal operating range and the current grid voltage operating range will not damage the hardware, stopping the signal transmission instead of tripping the circuit breaker helps reduce the number of circuit breaker operations, improve the service life of the circuit breaker, and enhance the stability of grid operation. Attached Figure Description

[0017] Figure 1 A schematic flowchart of the grid voltage adaptive control method for energy storage converters provided in the embodiments of this application; Figure 2 This is a schematic diagram of the per-unit voltage normalization process provided in an embodiment of this application; Figure 3 This is a schematic diagram of a low-voltage ride-through curve provided in an embodiment of this application; Figure 4 This is a schematic diagram of a high-voltage ride-through curve provided in an embodiment of this application; Figure 5 This is a schematic diagram of the voltage-reactive power increment curve provided in the embodiments of this application; Figure 6 A schematic diagram of the structure of the energy storage converter grid voltage adaptive control device provided in the embodiments of this application. Detailed Implementation

[0018] In this embodiment of the application, unless otherwise stated, the character " / " indicates that the preceding and following objects are in an OR relationship. For example, A / B can represent A or B. "AND / OR" describes the relationship between the associated 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.

[0019] It should be noted that the terms "first" and "second" used in the embodiments of this application are used only for distinguishing descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated, nor should they be construed as indicating or implying order.

[0020] In the embodiments of this application, "at least one" means one or more, and "more than one" means two or more. Furthermore, "at least one of the following" or similar expressions refer to any combination of these items, which may include any combination of a single item or a plurality of items. For example, at least one of A, B, or C can represent: A, B, C, A and B, A and C, B and C, or A, B, and C. Each of A, B, and C can be an element itself or a set containing one or more elements.

[0021] In this application, terms such as "exemplary," "in some embodiments," and "in another embodiment" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the term "exemplary" is intended to present the concept in a concrete manner.

[0022] In the embodiments of this application, the terms "of," "corresponding (relevant)," and "corresponding" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction, their meanings are consistent. Similarly, in the embodiments of this application, "communication" and "transmission" may sometimes be used interchangeably. It should be noted that, without emphasizing the distinction, their meanings are consistent. For example, transmission can include sending and / or receiving, and can be a noun or a verb.

[0023] In the embodiments of this application, the term "equal to" can be used in conjunction with "greater than" to apply to technical solutions employing the condition of "greater than", and can also be used in conjunction with "less than" to apply to technical solutions employing the condition of "less than". It should be noted that when "equal to" is used with "greater than", it cannot be used with "less than"; and when "equal to" is used with "less than", it cannot be used with "greater than".

[0024] First, the key terms involved in the embodiments of this application will be introduced.

[0025] (1) Blocking / Stop transmitting: This means that the power devices (such as IGBT, MOSFET, etc.) of the PCS are switched off, and the Pulse Width Modulation (PWM) signal is stopped from being sent to the PCS. This PWM signal is also called PWM wave, thereby controlling the PCS to stop working.

[0026] (2) Wave generation: refers to the closing of the power devices (such as IGBT, MOSFET, etc.) of the PCS to send PWM waves to the PCS.

[0027] (3) Disconnect the circuit breaker and shut down: By means of electrical control signals or manual operation, the contacts of the circuit breaker are separated (i.e., the circuit breaker is opened), and the electrical connection between the PCS and the power grid or battery is cut off. After the circuit breaker is opened, the control unit of the PCS detects the circuit breaker status and triggers the shutdown procedure (such as turning off the IGBT, stopping PWM modulation, etc.).

[0028] (4) Closing: refers to the circuit breaker contacts closing to maintain the electrical connection between the PCS and the power grid or battery.

[0029] (5) Low Voltage Ride-Through (LVRT): This refers to the state in which the equipment (PCS) remains connected to the grid and actively supports the grid recovery when the grid voltage suddenly drops to a lower level (usually 20% to 90% of the rated voltage) due to a fault (such as a short circuit or grounding).

[0030] (6) High Voltage Ride-Through (HVRT): When the grid voltage suddenly rises to a value exceeding the rated value (usually >110%), the equipment (PCS) maintains grid connection for a specified time.

[0031] (7) Zero Voltage Ride-Through (ZVRT): When the grid voltage drops to near 0% due to a serious fault (such as a three-phase short circuit at the near end), the equipment (PCS) maintains its grid connection capability for a very short time (milliseconds).

[0032] In related technologies, the adaptive control method of energy storage converters to grid voltage does not consider the lifespan of circuit breakers. When the grid voltage exceeds the normal operating range, the converter simply trips and shuts down. However, the circuit breaker, a key component in energy storage converters, has a limited number of opening and closing cycles. Excessive circuit breaker opening and closing will affect its lifespan, and frequent circuit breaker operation can easily cause grid fluctuations, affecting the stability of grid operation. Furthermore, the high cost of replacing circuit breakers will increase the hardware cost of energy storage converters.

[0033] Based on the above problems, this application proposes an adaptive control method for grid voltage of energy storage converter, which helps to reduce the number of circuit breaker operations, increase the service life of circuit breakers, and improve the stability of grid operation.

[0034] Now combined Figures 1-5 The adaptive grid voltage control method for energy storage converters provided in the embodiments of this application will be described.

[0035] Figure 1 A flowchart illustrating the adaptive grid voltage control method for energy storage converters provided in this application embodiment is shown, specifically including the following steps: Step S11: Obtain the current grid voltage information.

[0036] The real-time grid voltage information is obtained by resistor voltage division sampling, which includes the three-phase grid voltage signals.

[0037] Step S12: Based on the preset grid voltage reference value, the current grid voltage information is normalized to obtain the current grid voltage per-unit value.

[0038] In this step, the current grid voltage information obtained in step S11 is normalized to eliminate the influence of voltage level and dimension, and at the same time, it helps to judge the operating status of the grid based on the grid voltage per unit value.

[0039] In some alternative embodiments, such as Figure 2 As shown, Figure 2 This is a schematic diagram of the per-unit voltage normalization process provided in an embodiment of this application. Step S12 may specifically include: Step S121: Perform preset coordinate transformation and preset filtering operations on the current grid voltage information to obtain the current positive sequence d-axis filtered component and the current positive sequence q-axis filtered component corresponding to the current grid voltage information.

[0040] The current grid voltage information includes three-phase grid voltage signals. The acquired three-phase grid voltage signals undergo preset coordinate transformation and preset filtering operations. The preset coordinate transformation includes converting the three-phase stationary coordinate system (abc) to a two-phase stationary coordinate system (abc). The transformation of the two-phase stationary coordinate system ( ) to a two-phase rotating coordinate system ( The transformation of ) . The preset filtering operations include low-pass filtering.

[0041] Specifically, the three-phase stationary coordinate system (abc) is transformed into a two-phase stationary coordinate system via Clarke transformation. Two-phase stationary coordinate system ( Transformed into a two-phase rotating coordinate system via Park transformation. Transformation of ).

[0042] First, the three-phase grid voltage signal is transformed from the three-phase stationary coordinate system (abc) to the two-phase stationary coordinate system ( The transformation expression is as follows: in, , , The collected three-phase power grid voltage signals, , For the acquisition of power grid voltage signals Quantity, The Clarke transformation matrix is ​​expressed as follows: Next, Different components in a stationary coordinate system are transformed into different rotational coordinate systems. The component, expressed as follows: in ,when When represents the positive-order dq component, when Time represents the negative-order dq component. , for coordinate system ordinal component, The Park transformation matrix is ​​expressed as follows: Finally, in ascending order... The components are low-pass filtered to remove other ordered components, resulting in the positive-order components. The filtered components, namely the current positive sequence d-axis filtered component and the current positive sequence q-axis filtered component corresponding to the current grid voltage information, are expressed as follows: in Indicates low-pass filtering. This represents the current positive-order d-axis filtered component. This is the current positive-order q-axis filtered component.

[0043] Step S122: Determine the effective value of the current positive sequence line voltage amplitude based on the current positive sequence d-axis filtered component and the current positive sequence q-axis filtered component.

[0044] Specifically, the effective value of the current positive sequence line voltage amplitude is obtained by calculating the amplitude of the current positive sequence d-axis filtered component and the current positive sequence q-axis filtered component, as shown in the following expression: in This is the effective value of the current positive sequence line voltage amplitude.

[0045] Step S123: Determine the current grid voltage per unit value based on the preset grid voltage reference value and the current positive sequence line voltage amplitude effective value.

[0046] Specifically, the calculation formula for the per-unit value of the current grid voltage is as follows: Where is the per-unit value of the current grid voltage, is the preset reference value of the grid voltage.

[0047] Step S13: Determine the operating state of the power grid based on the per-unit value of the current grid voltage.

[0048] The operating state of the power grid is any one of the normal operating state, the low-ride-through state, the high-ride-through state, and the zero-ride-through state.

[0049] In some optional embodiments, determining the operating state of the power grid based on the per-unit value of the current grid voltage includes: When A2 < the per-unit value of the current grid voltage ≤ A1, the operating state of the power grid is the high-ride-through state; When A3 ≤ the per-unit value of the current grid voltage ≤ A2, the operating state of the power grid is the normal operating state; When A4 ≤ the per-unit value of the current grid voltage < A3, the operating state of the power grid is the low-ride-through state; When the per-unit value of the current grid voltage < A4, the operating state of the power grid is the zero-ride-through state; Where A1 > A2 > A3 > A4.

[0050] Optionally, A1 = 1.3, A2 = 1.1, A3 = 0.9, A4 = 0.2. It can be understood that the values of A1, A2, A3, and A4 can be set according to actual situations.

[0051] Step S14: When the operating state of the power grid is the low-ride-through state or the high-ride-through state, obtain the first duration, where the first duration is the duration when the power grid is in the low-ride-through state or the high-ride-through state.

[0052] When the grid voltage is not within the normal operating range, the energy storage converter will record the time when the grid voltage is not within the normal operating range. For example, the normal operating range of the per-unit value of the grid voltage is [0.9 pu, 1.1 pu]. When the per-unit value of the grid voltage is less than 0.9 pu or greater than 1.1 pu, the energy storage converter will start recording the time

[0053] When the operating state of the power grid is the low-ride-through state, obtain the first duration, where the first duration is the duration when the power grid is in the low-ride-through state; or when the operating state of the power grid is the high-ride-through state, obtain the first duration, where the first duration is the duration when the power grid is in the high-ride-through state.

[0054] Step S15: Determine whether the combination of the current grid voltage per unit value and the first duration meets the preset standard. If it does not meet the standard, stop transmitting waves and keep the circuit breaker in the closed state.

[0055] In this application, by judging the operating range of the grid voltage, under the premise that the current grid voltage exceeds the normal operating range and the current grid voltage operating range will not damage the hardware devices (the current grid is in a low-voltage or high-voltage state), the circuit breaker is kept in the closed state by stopping the wave transmission instead of tripping and shutting down. This helps to reduce the number of circuit breaker operations (tripping or closing), improve the service life of the circuit breaker, and improve the stability of grid operation.

[0056] In some optional embodiments, the preset standard includes a standard correspondence between the grid voltage per-unit value and the normal low-voltage transmission duration or the normal high-voltage transmission duration; determining whether the combination of the current grid voltage per-unit value and the first duration meets the preset standard includes: determining a second duration based on the current grid voltage per-unit value and the standard correspondence, wherein the second duration is the normal low-voltage transmission duration or the normal high-voltage transmission duration corresponding to the current grid voltage per-unit value; if the first duration is less than or equal to the second duration, then the combination of the current grid voltage per-unit value and the first duration meets the preset standard; or if the first duration is greater than the second duration, then the combination of the current grid voltage per-unit value and the first duration does not meet the preset standard.

[0057] like Figure 3 and Figure 4 As shown, Figure 3 This is a schematic diagram of a low-voltage ride-through curve provided in an embodiment of this application. Figure 4 This is a schematic diagram of a high-voltage ride-through curve provided in an embodiment of this application. Figure 3 The low voltage ride-through curve shown represents the standard correspondence between the per-unit value of the grid voltage and the normal low voltage ride-through duration when the grid is in a low voltage ride-through state. Figure 4 The high-voltage ride-through curve shown represents the standard correspondence between the per-unit voltage value of the power grid and the normal high-voltage ride-through duration when the power grid is in a high-voltage ride-through state.

[0058] In some embodiments, the current power grid state is in low-voltage mode. For example, the current combination of the grid voltage per unit value and the first duration is (u1, t1), that is... Figure 3 Point A in the diagram, the current grid voltage per unit value corresponding to point A is u1, the first duration corresponding to point A is t1, and the normal low-voltage ride-through duration corresponding to u1 is t2. Figure 3 As can be seen, t1 is less than t2. Therefore, the combination of the current grid voltage per unit value and the first duration (point A) meets the preset standard.

[0059] For example, the current combination of the per-unit value of the grid voltage and the first duration is (u1, t3), that is... Figure 3Point B in the diagram, the current grid voltage per unit value corresponding to point B is u1, the first duration corresponding to point B is t3, and the normal low-voltage ride-through duration corresponding to u1 is t2. Figure 3 As can be seen, t3 is greater than t2. Therefore, the combination of the current grid voltage per unit value and the first duration (point B) does not meet the preset standard.

[0060] In other embodiments, the current power grid state is in a high-voltage state. For example, the current combination of the per-unit value of the grid voltage and the first duration is (u2, t4), that is... Figure 4 Point C in the diagram corresponds to the current grid voltage per unit value of u2, the first time duration of point C is t4, and the normal high-voltage ride-through duration of u2 is 1 second. Figure 4 As can be seen, t4 is less than 1s. Therefore, the combination of the current grid voltage per unit value and the first duration (point C) meets the preset standard.

[0061] For example, the current combination of the per-unit value of the grid voltage and the first duration is (u2, t5), that is... Figure 4 Point D in the diagram corresponds to the current grid voltage per unit value u2, the first time duration corresponding to point D is t5, and the normal high-voltage ride-through time corresponding to u2 is 1 second. Figure 4 As can be seen, t5 is greater than 1s. Therefore, the combination of the current grid voltage per unit value and the first duration (point D) does not meet the preset standard.

[0062] If the current grid voltage per unit value and the first duration do not conform to the preset standard (e.g.) Figure 3 Point B in Figure 4 If the signal is at point D in the circuit, then the signal transmission will stop and the circuit breaker will remain in the closed state.

[0063] By comparing the duration of the grid in low-voltage mode with the normal low-voltage mode duration, or by comparing the duration of the grid in high-voltage mode with the normal high-voltage mode duration, when the duration of the grid in low-voltage mode exceeds the normal low-voltage mode duration, or the duration of the grid in high-voltage mode exceeds the normal high-voltage mode duration, waveform transmission is stopped, and the circuit breaker remains in the closed state. At this time, the energy storage converter still maintains its electrical connection with the grid, but it cannot operate due to the lack of a PWM wave drive signal. Replacing tripping with waveform transmission helps reduce the number of circuit breaker operations, extends the circuit breaker's lifespan, and improves the stability of grid operation.

[0064] In some optional embodiments, the energy storage converter grid voltage adaptive control method provided in this application further includes: when the grid is in a high-throughput state and the combination of the current grid voltage per unit value and the first duration meets a preset standard, absorbing reactive current; or when the grid is in a low-throughput state and the combination of the current grid voltage per unit value and the first duration meets a preset standard, outputting reactive current.

[0065] When the combination of the current grid voltage per unit value and the duration of the grid being in high-voltage state meets the preset standard, the energy storage converter absorbs reactive current, which helps to reduce the grid voltage, assists the grid voltage to return to the normal operating range as soon as possible, and supports grid stability.

[0066] Optionally, the absorbed reactive current is calculated based on the current grid voltage per-unit value. The current grid voltage per-unit value is directly proportional to the absorbed reactive current, and the calculation formula is as follows: in, To absorb reactive current, Rated current, This is the current grid voltage per unit value. It is a constant. .

[0067] When the combination of the current grid voltage per unit value and the duration of the grid being in a low-voltage state meets the preset standard, the energy storage converter outputs reactive current, which helps to boost the grid voltage, assists the grid voltage to recover to the normal operating range as soon as possible, and supports grid stability.

[0068] Optionally, the output reactive current is calculated based on the current grid voltage per-unit value. The current grid voltage per-unit value is directly proportional to the output reactive current, and the calculation formula is as follows: in, This refers to the reactive current output during low-voltage operation. Rated current, This is the current grid voltage per unit value. It is a constant. .

[0069] Calculating the reactive current value absorbed or output by the energy storage converter based on the current grid voltage per unit value helps to adaptively adjust the grid voltage, achieve precise support, avoid under-support or over-support, and smooth and stabilize the voltage.

[0070] In some optional embodiments, the energy storage converter grid voltage adaptive control method provided in this application further includes: when the current grid voltage per unit value is greater than A1, the circuit breaker is disconnected and the circuit is tripped to stop the power supply.

[0071] When the current grid voltage per unit value is greater than A1, it may damage the energy storage converter and other hardware equipment. In order to ensure the safety of the energy storage system, it is necessary to disconnect the electrical connection between the energy storage converter and the grid. Therefore, it is necessary to disconnect the circuit breaker and shut down the system.

[0072] In some optional embodiments, the energy storage converter grid voltage adaptive control method provided in this application further includes: when the grid is in normal operation, determining the voltage reactive power control state, which is either an enabled state or an disabled state; if the voltage reactive power control state is in an enabled state, calculating the reactive power increment based on the current grid voltage per unit value and the preset voltage reactive power control rules.

[0073] In this embodiment, when the power grid is operating normally, the energy storage converter obtains the voltage and reactive power control status through the main control device (such as a BMS (Battery Management System)). The main control device can send an enable flag for voltage and reactive power control to the energy storage converter; for example, "1" indicates an enabled state, and "0" indicates a disabled state. If the voltage and reactive power control status is enabled, the reactive power increment is calculated based on the current grid voltage per unit value and the preset voltage and reactive power control rules.

[0074] Figure 5 This is a schematic diagram of the voltage-reactive power increment curve provided in an embodiment of this application. Figure 5 As shown, the preset voltage reactive power control rules include: like If the output is reactive, the reactive power increment is greater than 0. like If the power grid operates normally, the reactive power increment is equal to 0. like If reactive power is absorbed, the reactive power increment will be less than 0.

[0075] in, This is the current grid voltage per unit value.

[0076] Compared to using a simple, fixed reactive power setpoint for grid voltage control, this application calculates the reactive power increment based on the current grid voltage per-unit value and preset voltage reactive power control rules, which can achieve smoother, more stable, and more intelligent voltage support.

[0077] In some optional embodiments, the energy storage converter grid voltage adaptive control method provided in this application further includes: when the grid is in the zero-push-through state, obtaining a third duration, the third duration being the duration of the grid in the zero-push-through state; if the third duration is less than or equal to the normal zero-push-through duration, then outputting reactive current; or if the third duration is greater than the normal zero-push-through duration, then disconnecting the circuit breaker and shutting down the system.

[0078] When the power grid is in the zero-push-through state, the duration of the power grid in the zero-push-through state is obtained. If the duration of the power grid in the zero-push-through state is longer than the normal zero-push-through duration, it may damage the energy storage converter and other hardware equipment. In order to ensure the safety of the energy storage system, it is necessary to disconnect the electrical connection between the energy storage converter and the power grid. Therefore, it is necessary to disconnect the circuit breaker and shut down the system.

[0079] If the duration of the power grid in the zero-push-out state is less than or equal to the normal zero-push-out duration, the energy storage converter can output reactive current to provide reactive power support to the power grid.

[0080] Optionally, the output current in the zero-breakdown state satisfies the following rule: like ,but ; like .

[0081] in, This refers to the reactive current output during zero-through-state operation. Rated current, This is the current grid voltage per unit value. It is a constant. .

[0082] Optionally, the normal zero-penetration duration is 150ms.

[0083] In some optional embodiments, the energy storage converter grid voltage adaptive control method provided in this application further includes: if the grid voltage returns to normal after the power grid voltage is stopped, the power grid voltage is restarted and the device is connected to the grid.

[0084] When the power grid is in a high-voltage or low-voltage state, and the energy storage converter stops transmitting PWM waves, waiting for the grid voltage to return to its normal operating range (e.g., 0.9 ≤ grid voltage per unit ≤ 1.1), the power devices of the energy storage converter re-send PWM waves, enabling the energy storage converter to operate normally in grid-connected mode. Compared to the control method of tripping the circuit breaker and then re-closing it after the grid voltage returns to normal, which requires manual reset, this application only requires retransmission of PWM waves to restore the energy storage converter to operation in a shorter time after the grid voltage returns to normal. This faster response speed helps improve grid stability. Furthermore, stopping and retransmitting PWM waves reduces the number of circuit breaker operations, extending the circuit breaker's lifespan.

[0085] Based on the same idea, this application also provides an energy storage converter grid voltage adaptive control device, such as... Figure 6 This is a schematic diagram of the structure of an energy storage converter grid voltage adaptive control device provided in an embodiment of this application. The energy storage converter grid voltage adaptive control device 60 mainly includes: The first acquisition module 61 is used to acquire the current power grid voltage information; The per-unit processing module 62 is used to perform per-unit processing on the current grid voltage information based on a preset grid voltage reference value to obtain the current grid voltage per-unit value; The first judgment module 63 is used to judge the operating status of the power grid based on the current per-unit value of the power grid voltage. The operating status of the power grid is any one of the following: normal operation, low voltage, high voltage and zero voltage. The second acquisition module 64 is used to acquire a first duration when the power grid is in a low-voltage state or a high-voltage state. The first duration is the duration during which the power grid is in a low-voltage state or a high-voltage state. The second judgment module 65 is used to determine whether the combination of the current grid voltage per unit value and the first duration meets the preset standard. If it does not meet the standard, the wave transmission is stopped and the circuit breaker is kept in the closed state.

[0086] This application provides a grid voltage adaptive control device for an energy storage converter. It acquires the current grid voltage information; standardizes the current grid voltage information based on a preset grid voltage reference value to obtain the current grid voltage per-unit value; determines the grid's operating state based on the current grid voltage per-unit value, where the grid operating state can be any one of normal operation, low-voltage operation, high-voltage operation, or zero-voltage operation; when the grid is in a low-voltage or high-voltage operation state, it acquires a first duration, which is the duration the grid is in the low-voltage or high-voltage operation state; it then determines whether the combination of the current grid voltage per-unit value and the first duration meets a preset standard. If not, it stops transmitting signals and keeps the circuit breaker in the closed state. By judging the grid voltage operating range, under the premise that the current grid voltage exceeds the normal operating range and the current grid voltage operating range will not damage the hardware, stopping signal transmission instead of tripping the circuit breaker helps reduce the number of circuit breaker operations, improves the service life of the circuit breaker, and enhances the stability of grid operation.

[0087] In one possible implementation, the preset standard includes a standard correspondence between the grid voltage per unit value and the normal low-voltage or normal high-voltage duration; the second judgment module 65 is also used for: Based on the current grid voltage per-unit value and standard correspondence, the second duration is determined. The second duration is the normal low-voltage transmission duration or normal high-voltage transmission duration corresponding to the current grid voltage per-unit value. If the first duration is less than or equal to the second duration, then the combination of the current grid voltage per unit value and the first duration meets the preset standard; or If the first duration is longer than the second duration, then the combination of the current grid voltage per unit value and the first duration does not meet the preset standard.

[0088] By comparing the duration of the grid in low-voltage mode with the normal low-voltage mode duration, or by comparing the duration of the grid in high-voltage mode with the normal high-voltage mode duration, when the duration of the grid in low-voltage mode exceeds the normal low-voltage mode duration, or the duration of the grid in high-voltage mode exceeds the normal high-voltage mode duration, waveform transmission is stopped, and the circuit breaker remains in the closed state. At this time, the energy storage converter still maintains its electrical connection with the grid, but it cannot operate due to the lack of a PWM wave drive signal. Replacing tripping with waveform transmission helps reduce the number of circuit breaker operations, extends the circuit breaker's lifespan, and improves the stability of grid operation.

[0089] In one possible implementation, the aforementioned energy storage converter grid voltage adaptive control device 60 further includes: The control module is used to absorb reactive current when the power grid is in high-voltage operation mode and the combination of the current grid voltage per unit value and the first duration meets a preset standard; or When the power grid is in low-voltage operation, the combination of the current grid voltage per unit value and the first duration meets the preset standard, and the reactive current is output.

[0090] When the combination of the current grid voltage per unit value and the duration of the grid being in high-voltage state meets the preset standard, the energy storage converter absorbs reactive current, which helps to reduce the grid voltage, assists the grid voltage to return to the normal operating range as soon as possible, and supports grid stability.

[0091] When the combination of the current grid voltage per unit value and the duration of the grid being in a low-voltage state meets the preset standard, the energy storage converter outputs reactive current, which helps to boost the grid voltage, assists the grid voltage to recover to the normal operating range as soon as possible, and supports grid stability.

[0092] In one possible implementation, the per-unit processing module 62 is also used for: Perform preset coordinate transformation and preset filtering operations on the current grid voltage information to obtain the current positive sequence d-axis filtered component and the current positive sequence q-axis filtered component corresponding to the current grid voltage information. The effective value of the current positive sequence line voltage amplitude is determined based on the current positive sequence d-axis filtered component and the current positive sequence q-axis filtered component. The current grid voltage per unit value is determined based on the preset grid voltage reference value and the effective value of the current positive sequence line voltage amplitude.

[0093] In one possible implementation manner, the first determination module 63 is further configured to: When A2 < the per-unit value of the current grid voltage ≤ A1, the operating state of the grid is the high ride-through state; When A3 ≤ the per-unit value of the current grid voltage ≤ A2, the operating state of the grid is the normal operating state; When A4 ≤ the per-unit value of the current grid voltage < A3, the operating state of the grid is the low ride-through state; When the per-unit value of the current grid voltage < A4, the operating state of the grid is the zero crossing state; Wherein, A1 > A2 > A3 > A4.

[0094] In one possible implementation manner, the second determination module 65 is further configured to: When the per-unit value of the current grid voltage > A1, disconnect the circuit breaker and trip and stop.

[0095] When the per-unit value of the current grid voltage > A1, it may damage the energy storage converter and other hardware devices. To ensure the safety of the energy storage system, it is necessary to disconnect the electrical connection between the energy storage converter and the grid. Therefore, it is necessary to disconnect the circuit breaker and trip and stop.

[0096] In one possible implementation manner, the above-mentioned energy storage converter grid voltage adaptive control device 60 further includes: A third determination module, configured to determine the voltage and reactive power control state when the operating state of the grid is the normal operating state, and the voltage and reactive power control state is one of the enabled state or the disabled state; If the voltage and reactive power control state is the enabled state, calculate the reactive power increment according to the per-unit value of the current grid voltage and the preset voltage and reactive power control rule.

[0097] In one possible implementation manner, the above-mentioned energy storage converter grid voltage adaptive control device 60 further includes: A third acquisition module, configured to acquire a third duration when the operating state of the grid is the zero crossing state, and the third duration is the duration of the grid in the zero crossing state; If the third duration is less than or equal to the normal zero crossing duration, output reactive current; or If the third duration is greater than the normal zero crossing duration, disconnect the circuit breaker and trip and stop.

[0098] When the operating state of the grid is the zero crossing state, acquire the duration of the grid in the zero crossing state. If the duration of the grid in the zero crossing state is greater than the normal zero crossing duration, it may damage the energy storage converter and other hardware devices. To ensure the safety of the energy storage system, it is necessary to disconnect the electrical connection between the energy storage converter and the grid. Therefore, it is necessary to disconnect the circuit breaker and trip and stop.

[0099] If the duration of the power grid in the zero-push-out state is less than or equal to the normal zero-push-out duration, the energy storage converter can output reactive current to provide reactive power support to the power grid.

[0100] In one possible implementation, the control module is also used for: If the grid voltage returns to normal after the waveform transmission stops, the waveform transmission will resume and the system will be connected to the grid again.

[0101] When the power grid is in a high-voltage or low-voltage state, and the energy storage converter stops transmitting PWM waves, waiting for the grid voltage to return to its normal operating range (e.g., 0.9 ≤ grid voltage per unit ≤ 1.1), the power devices of the energy storage converter re-send PWM waves, enabling the energy storage converter to operate normally in grid-connected mode. Compared to the control method of tripping the circuit breaker and then re-closing it after the grid voltage returns to normal, which requires manual reset, this application only requires retransmission of PWM waves to restore the energy storage converter to operation in a shorter time after the grid voltage returns to normal. This faster response speed helps improve grid stability. Furthermore, stopping and retransmitting PWM waves reduces the number of circuit breaker operations, extending the circuit breaker's lifespan.

[0102] Figure 6 The energy storage converter grid voltage adaptive control device 60 provided in the embodiment shown can be used to execute the technical solution of the method embodiment shown in this application. Its implementation principle and technical effect can be further referred to the relevant description in the method embodiment.

[0103] The above should be understood Figure 6 The division of the modules in the energy storage converter grid voltage adaptive control device 60 shown is merely a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, these modules can be implemented entirely in software via processing element calls; they can be fully implemented in hardware; or some modules can be implemented in software via processing element calls, while others are implemented in hardware. For example, the first acquisition module can be a separate processing element or integrated into a chip in an electronic device. The implementation of other modules is similar. In addition, these modules can be fully or partially integrated together, or implemented independently. During implementation, each step of the above method or each of the above modules can be completed through integrated logic circuits in the hardware of the processor element or through software instructions.

[0104] For example, these modules can be one or more integrated circuits configured to implement the above methods, such as one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs). Alternatively, these modules can be integrated together as a system-on-a-chip (SOC).

[0105] In the above embodiments, the processor may include, for example, a CPU, DSP, microcontroller, or digital signal processor, and may also include a GPU, embedded neural network processing unit (NPU), and image signal processor (ISP). The processor may also include necessary hardware accelerators or logic processing hardware circuits, such as an ASIC, or one or more integrated circuits for controlling the execution of the program in this application. Furthermore, the processor may have the function of operating one or more software programs, which may be stored in a storage medium.

[0106] This application also provides an energy storage converter, including: a processor and a memory, wherein the memory is used to store a computer program; the processor is used to run the computer program to implement the grid voltage adaptive control method for the energy storage converter provided in the embodiments of this application.

[0107] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0108] The above description is merely a specific embodiment of this application. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. The protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A grid voltage adaptive control device for an energy storage converter, characterized in that, Comprising: A first judgment module, configured to judge the operating state of the power grid according to the current grid voltage, and the operating state of the power grid includes a low-ride-through state and a high-ride-through state; An acquisition module, configured to acquire a first duration, and the first duration is the duration when the power grid is in a low-ride-through state or a high-ride-through state; A second judgment module, configured to judge whether the combination of the per-unit value of the current grid voltage and the first duration meets a preset standard, and if not, stop wave generation and keep the circuit breaker in the closed state.

2. The energy storage converter grid voltage adaptive control device according to claim 1, characterized in that, The preset standard includes the standard correspondence relationship between the per-unit value of the grid voltage and the normal low-ride-through duration or the normal high-ride-through duration; The second judgment module is further configured to: Based on the per-unit value of the current grid voltage and the standard correspondence relationship, determine a second duration, and the second duration is the normal low-ride-through duration or the normal high-ride-through duration corresponding to the per-unit value of the current grid voltage; If the first duration is less than or equal to the second duration, the combination of the per-unit value of the current grid voltage and the first duration meets the preset standard; Or If the first duration is greater than the second duration, the combination of the per-unit value of the current grid voltage and the first duration does not meet the preset standard.

3. The energy storage converter grid voltage adaptive control device according to claim 1 or 2, characterized in that, The device further includes: A control module, configured to absorb reactive current when the operating state of the power grid is a high-ride-through state and the combination of the per-unit value of the current grid voltage and the first duration meets the preset standard; or Output reactive current when the operating state of the power grid is a low-ride-through state and the combination of the per-unit value of the current grid voltage and the first duration meets the preset standard.

4. The energy storage converter grid voltage adaptive control device according to claim 3, wherein Calculate the absorbed reactive current according to the per-unit value of the current grid voltage, and the per-unit value of the current grid voltage is in direct proportion to the absorbed reactive current.

5. The energy storage converter grid voltage adaptive control device according to claim 3, wherein Calculate the output reactive current according to the per-unit value of the current grid voltage, and the per-unit value of the current grid voltage is in direct proportion to the output reactive current.

6. The energy storage converter grid voltage adaptive control device according to claim 1, wherein The first judgment module is further configured to: When A2 < the per-unit value of the current grid voltage ≤ A1, the operating state of the power grid is a high-ride-through state; When A4 ≤ the per-unit value of the current grid voltage < A3, the operating state of the power grid is a low-ride-through state; Wherein, A1 > A2 > A3 > A4.

7. The energy storage converter grid voltage adaptive control device according to claim 6, wherein The second judgment module is further configured to: When the per-unit value of the current grid voltage > A1, disconnect the circuit breaker and trip and stop.

8. The energy storage converter grid voltage adaptive control device according to claim 1, characterized in that, ​ ​ ​ ​ If the third duration is longer than the normal zero-break duration, the circuit breaker will be disconnected and the circuit will be tripped and the machine will be shut down.

9. The energy storage converter grid voltage adaptive control device according to claim 3, characterized in that, The control module is also used for: If the grid voltage returns to normal after the signal transmission stops, the signal transmission will resume and the system will be connected to the grid again.

10. The energy storage converter grid voltage adaptive control device according to claim 1, characterized in that, The operating status of the power grid also includes a normal operating status, and the device further includes: The third judgment module is used to judge the voltage reactive power control state when the power grid is in normal operation state, wherein the voltage reactive power control state is either an enabled state or an disabled state. If the voltage reactive power control state is enabled, then the reactive power increment is calculated based on the current grid voltage per unit value and the preset voltage reactive power control rules.

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