Flexible load-based dc bus voltage support recovery control method and device

Abstract

The application provides a flexible load-based DC bus voltage support recovery control method and device, and mainly relates to the technical field of DC micro-grid control. The method comprises the following steps: in response to the bus voltage of the DC bus deviating from the bus reference voltage, adjusting the operating power of the flexible load according to the voltage deviation of the bus voltage relative to the bus reference voltage at the first time, the rated voltage of the flexible load and the recovery variable; determining the cumulative support energy based on the cumulative power deviation energy of the flexible load and the estimated recovery deviation energy; in the case that the cumulative support energy is greater than or equal to the energy budget threshold of the flexible load, adjusting the recovery variable from the first value to the second value, so that the operating power of the flexible load changes smoothly to the rated power, and in the case that the flexible load operates at the rated power for the first length of time, adjusting the recovery variable from the second value back to the first value, so that the flexible load recovers the voltage support state.

Description

Technical Field

[0001] This invention relates to the field of DC microgrid control technology, and more specifically, to a DC bus voltage support recovery control method and device based on flexible load. Background Technology

[0002] DC microgrids offer advantages in the efficient integration of renewable energy and DC loads, but source-load fluctuations pose challenges to bus voltage stability. Flexible loads are loads that can flexibly adjust their power according to grid conditions, providing rapid voltage support through converter interfaces. However, existing control schemes utilizing flexible loads for voltage support are prone to causing long-term damage to the load's inherent function after providing support, or triggering power surges during load state switching, thus affecting the stable operation of the DC microgrid. Summary of the Invention

[0003] In view of this, the present invention provides a method and apparatus for DC bus voltage support recovery control based on flexible load.

[0004] One aspect of the present invention provides a DC bus voltage support recovery control method based on a flexible load, comprising: responding to a deviation of the DC bus voltage from a bus reference voltage, adjusting the operating power of the flexible load according to the voltage deviation of the bus voltage relative to the bus reference voltage at a first moment, the rated voltage of the flexible load, and a recovery variable, so that the flexible load provides voltage support to the DC bus, wherein the recovery variable has a first value at the first moment; determining the cumulative support energy of the flexible load in the target time period based on the cumulative power deviation energy caused by the voltage support in the flexible load during the target time period and the estimated recovery deviation energy required for the flexible load to recover the voltage support state, wherein the target time period is determined based on the first moment and a second moment following the first moment; when the cumulative support energy is greater than or equal to the energy budget threshold of the flexible load, adjusting the recovery variable from the first value to a second value so that the operating power of the flexible load smoothly changes to the rated power, and when the flexible load operates at the rated power for a predetermined first time, adjusting the recovery variable from the second value back to the first value so that the flexible load recovers the voltage support state.

[0005] Another aspect of the present invention provides a DC bus voltage support recovery control device based on a flexible load, applicable to the voltage support recovery control method as described in any of the preceding claims. The voltage support recovery control device includes: an adjustment module, configured to adjust the operating power of the flexible load based on the voltage deviation of the bus voltage relative to the bus reference voltage at a first moment, the rated voltage of the flexible load, and a recovery variable, in response to a deviation of the bus voltage from the bus reference voltage, so that the flexible load provides voltage support to the DC bus, wherein the recovery variable is a first value at the first moment; and a determination module, configured to determine the cumulative power deviation caused by the voltage support during a target time period of the flexible load. The differential energy and the estimated recovery deviation energy required for the flexible load to restore voltage support state are used to determine the cumulative support energy of the flexible load during the target time period, wherein the target time period is determined based on the first moment and a second moment after the first moment; the control module is used to adjust the recovery variable from a first value to a second value when the cumulative support energy is greater than or equal to the energy budget threshold of the flexible load, so that the operating power of the flexible load changes smoothly to the rated power, and when the flexible load operates at the rated power for a preset first time, adjust the recovery variable from the second value back to the first value, so that the flexible load restores voltage support state.

[0006] Embodiments of this invention quantify the transient voltage support capability of flexible loads into an energy budget and manage the support process based on real-time calculation of accumulated support energy. This allows for precise measurement of the effort required by flexible loads to provide voltage support, ensuring a bounded and controllable support process. Furthermore, all support and recovery decisions can be completed in a closed loop relying solely on local bus voltage information, eliminating the need for communication between controllers. This makes flexible loads a quantifiable and autonomously manageable grid regulation resource, providing a low-cost and easily scalable means of voltage stabilization for DC microgrids with a high proportion of renewable energy integration. Attached Figure Description

[0007] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

[0008] Figure 1 A flowchart of a DC bus voltage support recovery control method based on flexible load according to an embodiment of the present invention is shown.

[0009] Figure 2 A schematic diagram of the recovery process according to a specific embodiment of the present invention is shown.

[0010] Figure 3A schematic diagram of a DC bus voltage support recovery control device based on a flexible load according to an embodiment of the present invention is shown.

[0011] Figure 4 A block diagram of an electronic device suitable for implementing a DC bus voltage support recovery control method based on a flexible load, according to an embodiment of the present invention, is shown. Detailed Implementation

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0013] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0014] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0015] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0016] DC microgrids offer significant advantages in efficiently integrating distributed renewable energy sources such as photovoltaics and wind power, as well as directly supplying power to DC loads like data centers and electric vehicle charging stations, making them a crucial development direction for modern power systems. Maintaining stable DC bus voltage is a core requirement for the safe operation of DC microgrids. However, the intermittency of renewable energy output and the volatility of load demand pose serious challenges to the real-time power balance of the DC bus. Relying solely on expanding energy storage capacity to address these challenges faces considerable pressure in terms of both economic viability and sustainability.

[0017] Flexible loads refer to loads that can flexibly adjust their power consumption within a certain range according to the grid conditions, such as air conditioners, electric vehicles, and data centers. Through power electronic converter interfaces, these loads have the potential to provide rapid voltage support to the grid.

[0018] Currently, methods for supporting DC bus voltage using flexible loads typically adjust load power based on a pre-defined voltage-power mapping relationship. However, this pre-defined mapping relationship cannot adapt to the actual duration and severity of grid disturbances. If the load's power reduction support time is too long or the magnitude is too large, its own function will be excessively suppressed. If it switches back to rated operation before the grid has stabilized, it is prone to grid shocks due to sudden power changes. This contradiction between the continuity of support and the safety of the load's own operation limits the practical application of flexible loads in DC microgrid voltage stabilization.

[0019] In view of this, embodiments of the present invention provide a DC bus voltage support recovery control method based on flexible loads. This method quantifies the transient voltage support capability of flexible loads into an energy budget and manages the support process based on real-time calculation of accumulated support energy. This allows for precise measurement of the effort expended by flexible loads when providing voltage support, ensuring the support process is bounded and controllable and preventing damage to the load's own function due to over-support. Simultaneously, after the support ends, a smooth recovery process ensures that the operating power returns to its rated value without abrupt changes, preventing secondary power surges to the power grid. Furthermore, all the decisions regarding support and recovery can be made solely based on local bus voltage information, eliminating the need for communication between controllers. This achieves decentralized autonomous control, reducing system implementation costs and deployment complexity, and providing an economical and scalable voltage stabilization method for DC microgrids with a high proportion of renewable energy integration.

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0021] Figure 1 A flowchart of a DC bus voltage support recovery control method based on flexible load according to an embodiment of the present invention is shown.

[0022] like Figure 1 As shown, the DC bus voltage support recovery control method includes operations S110 to S140.

[0023] In operation S110, in response to the deviation of the DC bus voltage from the bus reference voltage, the operating power of the flexible load is adjusted based on the voltage deviation of the bus voltage relative to the bus reference voltage at the first moment, the rated voltage of the flexible load, and the recovery variable.

[0024] In operation S120, the cumulative support energy of the flexible load during the target period is determined based on the cumulative power deviation energy caused by voltage support of the flexible load during the target period and the estimated recovery deviation energy required for the flexible load to recover to the voltage support state.

[0025] In operation S130, when the accumulated support energy is greater than or equal to the energy budget threshold of the flexible load, the operating power of the flexible load is smoothly changed to the rated power by adjusting the recovery variable from the first value to the second value. When the flexible load operates at the rated power for a preset first time, the recovery variable is adjusted back from the second value to the first value, so that the flexible load returns to the voltage support state.

[0026] Flexible loads are loads that actively adjust their power consumption based on the grid conditions through their power electronic interfaces. Examples include air conditioning systems, electric vehicles, and data centers.

[0027] A DC bus can be a common DC connection point in a DC aggregation network that connects distributed power sources, energy storage units, and various loads. In this embodiment, the bus voltage is the voltage at this common connection point.

[0028] The bus reference voltage can be the rated or optimized setting that the system expects the bus voltage to be maintained at.

[0029] The first moment can be the starting moment when the flexible load begins to provide voltage support to the DC bus.

[0030] A recovery variable can be used to characterize the voltage support capability of a flexible load. In this embodiment, the value of the recovery variable can vary between a first value and a second value, with different values ​​corresponding to different voltage support capabilities of the flexible load.

[0031] Operating power can be the electrical power actually consumed by the flexible load from the DC bus at the current moment.

[0032] In this embodiment, the controller monitors the DC bus voltage in real time. When the bus voltage deviates from the bus reference voltage (e.g., when the bus voltage drops below the bus reference voltage due to a decrease in renewable energy output or a sudden load surge), the controller acquires the voltage deviation of the bus voltage relative to the bus reference voltage at a first moment. Based on this voltage deviation, the rated voltage of the flexible load, and the recovery variable, the controller dynamically adjusts the operating power of the flexible load so that the flexible load provides voltage support to the DC bus.

[0033] In some specific implementations, when the recovery variable is at its first value at the first moment, the power drawn from the DC bus by the flexible load can be actively controlled by changing the terminal voltage reference value of the upstream converter. For example, when the bus voltage drops below the bus reference voltage, the controller reduces the operating power of the flexible load, which is equivalent to releasing some power space to the grid, thereby providing voltage support to the DC bus.

[0034] The second moment can be the current moment, which is after the first moment and is when the cumulative support energy assessment is performed.

[0035] The target time period can be the time interval from the beginning of the first moment to the end of the second moment.

[0036] The cumulative support energy can be a real-time estimate of the total energy cost required by the flexible load to complete this support task. In this embodiment, the cumulative support energy may include the cumulative power deviation energy and the estimated recovery deviation energy.

[0037] Cumulative power deviation energy can be the actual cumulative energy difference generated during the target period due to the operating power of flexible loads being lower than their rated power. It can be used to represent the energy that flexible loads have already contributed to the power grid.

[0038] The estimated recovery deviation energy can be an estimate of the additional energy required for the flexible load to smoothly recover from its operating power to its rated power at the second time point, based on the power deviation level at the second time point.

[0039] In this embodiment, as the flexible load provides voltage support, the load continuously consumes its own energy margin. To accurately measure the energy margin continuously consumed by the load, the cumulative support energy can be continuously calculated over a target time period.

[0040] The energy budget threshold can be used to characterize the maximum cumulative energy cost that a flexible load is allowed to pay to provide transient voltage support.

[0041] The first duration can be a preset duration for the flexible load to operate stably at rated power during the recovery process.

[0042] In this embodiment, the controller compares the accumulated support energy with a preset energy budget threshold. When the accumulated support energy is greater than or equal to the energy budget threshold, it indicates that the flexible load has reached its allowable upper limit of support energy, and continuing to provide voltage support would impair its own functionality. At this point, a recovery process is triggered.

[0043] Specifically, the control recovery variable is adjusted from its first value to its second value. This change in the value of the recovery variable weakens the response of the flexible load to voltage deviations, allowing its operating power to smoothly change from a reduced-power support state to its rated power, thereby avoiding secondary impacts on the power grid caused by sudden power changes.

[0044] After the operating power is restored to rated power, the flexible load is controlled to continue operating at rated power for a pre-set first duration. During this rated operation period, the inherent functions of the flexible load are fully restored. For example, the air conditioning system can cool at full power during this period to compensate for the temperature deviation accumulated during the support period, and the data center can operate at full speed to process the backlog of computing tasks.

[0045] After the flexible load operates at rated power for a first period of time, the control recovery variable is adjusted back from the second value to the first value. As the value of the recovery variable changes, the voltage support capability of the flexible load is reactivated, thereby restoring the voltage support state and preparing for the next response to a DC bus voltage deviation event.

[0046] Based on this, embodiments of the present invention quantify the transient voltage support capability of flexible loads into an energy budget and manage the support process based on real-time calculation of accumulated support energy. This allows for precise measurement of the effort expended by flexible loads when providing voltage support, ensuring a bounded and controllable support process and preventing damage to the load's own function due to over-support. Simultaneously, after support ends, a smooth recovery process ensures that the operating power returns to its rated value without abrupt changes, preventing secondary power surges to the grid. Furthermore, all the decisions regarding support and recovery can be made solely based on local bus voltage information, eliminating the need for communication between controllers. This achieves decentralized autonomous control, reducing system implementation costs and deployment complexity, and providing an economical and scalable voltage stabilization method for DC microgrids with a high proportion of renewable energy integration.

[0047] According to an embodiment of the present invention, the voltage support recovery control method further includes: obtaining the terminal voltage of the flexible load; determining the rated voltage, rated power, and load parameters of the flexible load according to the load type of the flexible load, wherein the load parameters include a constant power component weighting coefficient, a constant current component weighting coefficient, and a constant impedance component weighting coefficient; and calculating the operating power based on the terminal voltage, rated voltage, rated power, and load parameters.

[0048] The terminal voltage of a flexible load refers to the actual voltage value at the input port of the upstream converter of the flexible load.

[0049] The load type of a flexible load can be a classification of the flexible load according to its electrical characteristics. In this embodiment, the load type of a flexible load can include constant impedance load, constant current load, constant power load, etc. For example, lighting loads can be classified as constant impedance loads, heating equipment can be classified as constant current loads, and data centers can be classified as constant power loads.

[0050] The load parameters of a flexible load can be parameters used to quantitatively describe the power-voltage characteristics of the flexible load. In this embodiment, the load parameters of the flexible load may include a constant power component weighting coefficient A. P Weighting coefficient A for constant current component I And the weighting coefficient A of the constant impedance component Z All three satisfy A. P +A I +A Z =1. In some specific implementations, these coefficients can be determined based on empirical values ​​pre-configured according to load type statistics.

[0051] In this embodiment, before performing voltage support recovery control, a general load model of the flexible load can be established to determine the current actual operating power of the flexible load.

[0052] Specifically, the actual terminal voltage V of the i-th flexible load can be obtained first through a voltage sensor. Ld,i And based on the load type of the flexible load, determine its relevant parameters, such as the rated voltage V of the i-th flexible load. Ld,iRate Rated power P rate And a set of load parameters, such as the constant power component weighting factor A. P Weighting coefficient A for constant current component I And the weighting coefficient A of the constant impedance component Z .

[0053] After obtaining the above key parameters, the actual terminal voltage V of the i-th flexible load can be used as a reference. Ld,i The rated voltage V of the i-th flexible load Ld,iRate Rated power P rate Based on the load parameters, the actual operating power P of the i-th flexible load is calculated using a general load model. Ld,i .

[0054] According to an embodiment of the present invention, the operating power is calculated based on the terminal voltage, rated voltage, rated power, and load parameters, including: determining the per-unit voltage value based on the terminal voltage and rated voltage; determining the constant current component based on the per-unit voltage value and the weighting coefficient of the constant current component; determining the constant impedance component based on the square of the per-unit voltage value and the weighting coefficient of the constant impedance component; and obtaining the operating power based on the sum of the constant power component, the constant current component, and the constant impedance component, wherein the constant power component is determined by the weighting coefficient of the constant power component.

[0055] The per-unit voltage value refers to the actual terminal voltage V of the i-th flexible load. Ld,i Divide by the rated voltage V of the i-th flexible load Ld,iRate The obtained ratio. When the actual terminal voltage V of the i-th flexible load... Ld,i The rated voltage V of the i-th flexible load Ld,iRate At that time, the per-unit voltage value is 1.

[0056] The constant power component can be the portion of the operating power of a flexible load that is independent of the terminal voltage. This portion of power remains constant as the terminal voltage changes. In some specific embodiments, this constant current power component can be determined by the rated power P. rate Weighting coefficient A of constant power component P The product is determined.

[0057] The constant current component can be the portion of the operating power of a flexible load that is proportional to the terminal voltage. Its physical characteristics are equivalent to a load with a constant effective current value, and its power can vary linearly with the terminal voltage. In some specific embodiments, this constant current component can be determined by the rated power P. rate Weighting coefficient A for constant current component I And the product of the per-unit voltage value is used to determine it.

[0058] The constant impedance component can be the portion of the operating power of a flexible load that is proportional to the square of the terminal voltage. Its physical characteristics are equivalent to a load with a constant impedance, whose power varies with the square of the terminal voltage. In some specific embodiments, this constant impedance component can be represented by the rated power P. rate Weighting coefficient A for constant impedance components Z And determined by the product of the squares of the per-unit voltage values.

[0059] In this embodiment, the operating power can be calculated based on the sum of the constant power component, constant current component, and constant impedance component, and the expression for the operating power is as follows:

[0060] (1);

[0061] in, P represents the current actual operating power of the i-th flexible load. rateA represents the rated power of the flexible load. P A represents the weighting coefficient for the constant power component. I A represents the weighting coefficient of the constant current component. Z V represents the weighting coefficient of the constant impedance component. Ld,i V represents the actual terminal voltage of the i-th flexible load. Ld,iRate This represents the rated voltage of the i-th flexible load.

[0062] Based on this, the embodiments of the present invention utilize the general load model shown in formula (1) to express the operating power of the load as a combination of three components: constant power, constant current, and constant impedance. This model can accurately describe the static power consumption characteristics of most power electronic loads. Using this model, the controller can accurately calculate the part of the operating power that changes according to the change in terminal voltage, providing accurate input for subsequent energy calculation and precise control.

[0063] According to an embodiment of the present invention, adjusting the operating power of a flexible load based on the voltage deviation of the bus voltage relative to the bus reference voltage at a first moment, the rated voltage of the flexible load, and the recovery variable includes: determining a reference voltage for the flexible load based on the voltage deviation, the rated voltage, and the recovery variable; and controlling the converter of the flexible load based on the reference voltage to adjust the operating power of the flexible load.

[0064] According to an embodiment of the present invention, controlling the converter of a flexible load based on a reference voltage to adjust the operating power of the flexible load includes: determining a target voltage adjustment factor based on voltage deviation, recovery variable, and support strength coefficient; and correcting the rated voltage of the flexible load using the target voltage adjustment factor to obtain a reference voltage.

[0065] A converter is a power electronic interface device, such as a DC-DC converter, that connects a flexible load to a DC bus. This converter transforms the bus voltage into the voltage required by the load and can adjust its port characteristics according to commands.

[0066] The reference voltage for a flexible load refers to the target voltage value set for the port of the upstream converter of the flexible load.

[0067] The target voltage adjustment factor can be the rated voltage V for the i-th flexible load. Ld,iRate The scaling factor is adjusted.

[0068] The support strength factor can be used to characterize the ability of flexible loads to participate in grid voltage support. The larger the support strength factor, the greater the power adjustment range of the flexible load under the same voltage deviation.

[0069] In this embodiment, the controller can indirectly adjust the operating power of the flexible load by adjusting the reference voltage of the upstream converter of the flexible load.

[0070] Specifically, the bus voltage of the DC bus can be obtained first from real-time monitoring. relative to the bus reference voltage The voltage deviation is calculated. In some specific implementations, the voltage deviation can be expressed as a ratio. .

[0071] After calculating the voltage deviation, the voltage deviation can be used to recover the variable k. Re,i and the support strength coefficient k GS,i The target voltage adjustment factor a is calculated. 0i In some specific implementations, the target voltage adjustment factor is calculated as follows:

[0072] (2);

[0073] Among them, a 0i k represents the target voltage adjustment factor. GS,i k represents the support strength coefficient. Re,i This indicates the variable to be restored.

[0074] In the above formula (2), the reference value 1 is used to ensure that the target voltage adjustment factor a is within the range of voltage deviation or support function withdrawal. 0i The default value is 1, meaning the rated voltage is not adjusted. Voltage deviation item. Used to reflect the direction and degree of deviation of the bus voltage. Support strength coefficient k GS,i This coefficient can be used to determine the load's response sensitivity to voltage deviations. The larger the coefficient, the higher the target voltage adjustment factor a will be under the same voltage deviation. 0i The greater the change, the better. (Restore variable k) Re,i It can be used to control whether the voltage deviation term is effective, when the recovery variable k Re,i When the value is the first value, the voltage deviation term is fully included; when the recovery variable k... Re,i When the value is the second value, the voltage deviation term is set to zero, and the target voltage adjustment factor a 0i It is always 1.

[0075] Based on formula (2), when the bus voltage drops (such as the bus voltage...) Less than the bus reference voltage And the flexible load is in a supported and activated state (e.g., the recovery variable k). Re,i When the value is the first value, the voltage deviation term is negative, making the target voltage adjustment factor a 0i Less than 1. The deeper the bus voltage drop, the lower the support strength coefficient k. GS,iThe larger the target voltage adjustment factor a is, the higher the target voltage adjustment factor α is. 0i The reduction is also greater. When the supporting function of the flexible load is withdrawn (such as when the variable k recovers), Re,i When the second value is used or the bus voltage is equal to the bus reference voltage, the target voltage adjustment factor a is... 0i It equals 1.

[0076] The target voltage adjustment factor a is calculated. 0i Then, the target voltage adjustment factor a can be used. 0i The rated voltage V of the i-th flexible load Ld,iRate Make corrections. Specifically, this can be based on the rated voltage V of the i-th flexible load. Ld,iRate With target voltage adjustment factor a 0i The product of these terms is used to calculate the reference voltage V of the i-th flexible load. Ld,iRef In one specific embodiment, the reference voltage is calculated as follows:

[0077] (3);

[0078] Based on formula (3), when the target voltage adjustment factor a 0i When the value is less than 1, the reference voltage V of the i-th flexible load is... Ld,iRef The voltage V below the rated voltage of the i-th flexible load Ld,iRate When the target voltage adjustment factor a 0i When the value equals 1, the reference voltage V of the i-th flexible load is... Ld,iRef Equal to the rated voltage V of the i-th flexible load Ld,iRate .

[0079] In this embodiment, the reference voltage V of the i-th flexible load is calculated. Ld,iRef Then, the reference voltage V of the i-th flexible load can be... Ld,iRef This command value is sent to the converter of the flexible load. After receiving the command, the converter uses closed-loop control to adjust the actual terminal voltage V of the flexible load. Ld,i Adjust to this reference voltage. Since the operating power of a flexible load is a function of its terminal voltage, changes in the terminal voltage will lead to corresponding changes in the operating power, thereby adjusting the operating power of the flexible load. For example, when the bus voltage drops, the target voltage adjustment factor a... 0i When the value is less than 1, the reference voltage decreases, the voltage at the converter control terminal decreases accordingly, and the operating power of the flexible load decreases accordingly. This is equivalent to releasing some power space to the grid, thereby providing voltage support for the DC bus.

[0080] Based on this, embodiments of the present invention, through the aforementioned control process, convert the voltage deviation signal of the power grid into a terminal voltage command for the flexible load interface converter, thereby indirectly adjusting the operating power of the flexible load. In the calculation of the target voltage adjustment factor, the voltage deviation reflects the actual degree of deviation of the power grid, the support strength coefficient determines the response amplitude of the load to the voltage deviation, and the recovery variable controls whether the response is effective. Furthermore, by comparing and limiting the calculated initial voltage adjustment factor with the preset adjustment range, it is ensured that the terminal voltage of the flexible load is always limited within its tolerable safe range, avoiding equipment damage caused by excessive voltage adjustment. The entire control structure is clearly hierarchical, the physical meaning of the parameters is clear, and it is easy to implement in a local controller.

[0081] According to an embodiment of the present invention, determining a target voltage adjustment factor based on voltage deviation, recovery variable, and support strength coefficient includes: determining an initial voltage adjustment factor based on voltage deviation, recovery variable, and support strength coefficient; comparing the initial voltage adjustment factor with a preset adjustment range to obtain a comparison result, wherein the preset adjustment range is determined by the maximum allowable adjustment ratio of the flexible load voltage; if the comparison result indicates that the initial voltage adjustment factor exceeds the preset adjustment range, determining a target voltage adjustment factor corresponding to the initial voltage adjustment factor based on the boundary value of the preset adjustment range exceeded by the initial voltage adjustment factor; if the comparison result indicates that the initial voltage adjustment factor is within the preset adjustment range, determining the initial voltage adjustment factor as the target voltage adjustment factor.

[0082] The initial voltage adjustment factor refers to the adjustment factor value directly calculated by formula (2), that is, the theoretical calculation result without any limiting processing.

[0083] The preset adjustment range can be a range of values ​​for the target voltage adjustment factor that is pre-set based on the physical withstand capability of the flexible load. This preset adjustment range can be determined by the maximum allowable adjustment ratio B0 of the flexible load voltage. The maximum allowable adjustment ratio can be the maximum allowable variation of the flexible load's terminal voltage relative to its rated voltage. The maximum allowable adjustment ratio B0 can be pre-set based on the voltage withstand capability of the load equipment itself. In one specific embodiment, the preset adjustment range can be set to [1-B0, 1+B0]. If B0=0.1, it means that the terminal voltage is allowed to vary between 90% and 110% of the rated voltage.

[0084] In this embodiment, the adjustment factor directly calculated by formula (2) is only an initial value. Before it is used to correct the rated voltage, it can also be limited to ensure that the terminal voltage of the flexible load does not exceed the safe range due to over-adjustment.

[0085] Specifically, the initial voltage adjustment factor can be calculated using formula (2) based on the voltage deviation, recovery variable, and support strength coefficient. The initial voltage adjustment factor is then compared with the preset adjustment range [1-B0, 1+B0].

[0086] If the comparison result indicates that the initial voltage adjustment factor exceeds the upper limit of the preset adjustment range, for example, the initial voltage adjustment factor is greater than 1+B0, then the upper limit boundary value 1+B0 is determined as the target voltage adjustment factor.

[0087] If the comparison result indicates that the initial voltage adjustment factor exceeds the lower limit of the preset adjustment range, for example, if the initial voltage adjustment factor is less than 1-B0, then the lower limit boundary value 1-B0 is determined as the target voltage adjustment factor.

[0088] If the comparison result indicates that the initial voltage adjustment factor is within the preset adjustment range, such as between [1-B0, 1+B0], then the initial voltage adjustment factor can be directly determined as the target voltage adjustment factor.

[0089] Therefore, the target voltage adjustment factor a is determined through this limiting process. 0i This can be used as the final value of the reference voltage calculated using formula (3).

[0090] Based on this, embodiments of the present invention add a voltage adjustment factor limiting link to the control loop, comparing the initial voltage adjustment factor directly calculated by formula (2) with a preset adjustment range. When the initial voltage adjustment factor exceeds the preset adjustment range due to drastic fluctuations in the grid voltage, it is limited to the boundary value determined by the maximum allowable adjustment ratio, ensuring that the target voltage adjustment factor used to calculate the reference voltage is always within a safe range. This method effectively prevents unexpected load shutdowns or damages caused by excessively low terminal voltages and equipment insulation damage caused by excessively high terminal voltages, ensuring the safe operation of load equipment while achieving voltage support.

[0091] The above describes how flexible loads adjust their operating power by regulating the reference voltage based on the DC bus voltage deviation, thereby providing voltage support to the DC bus. During this process, the operating power of the flexible load will deviate from its rated power, resulting in energy deviation. To ensure that the support capacity of the flexible load is bounded and its inherent function is not impaired, the accumulated energy deviation during the support process can be measured, and this can be used to determine when to stop support and initiate recovery. The calculation method for accumulated support energy and the recovery trigger criteria will be explained in detail below.

[0092] According to an embodiment of the present invention, the method based on the cumulative power deviation energy caused by voltage support of the flexible load during the target time period and the estimated recovery deviation energy required for the flexible load to restore the voltage support state includes: obtaining the cumulative power deviation energy based on the integral result of the power deviation between the operating power and the rated power during the target time period; obtaining the estimated recovery deviation energy based on the power deviation between the operating power and the rated power at a second time point and the second duration; and determining the cumulative support energy by summing the cumulative power deviation energy and the estimated recovery deviation energy.

[0093] The second duration can be used to characterize the estimated time required for the flexible load to recover from its current operating power to its rated power through a smoothing process. In this embodiment, the second duration is equal to the time it takes for the recovery variable to adjust from a first value to a second value during the subsequent recovery process.

[0094] In this embodiment, at the first moment T from the start of the support process p The target time period [tT] up to the second time t in the current assessment p Within the period [t], the power deviation between the actual operating power and the rated power of the flexible load is integrated, and the result of the integration is the cumulative power deviation energy. This integration result represents the actual energy deficit caused by the load operating at reduced power during the target time period. In one specific embodiment, the cumulative power deviation energy is calculated as follows:

[0095] (4);

[0096] in, T represents the cumulative power deviation energy. p Let t represent the first moment, and t represent the second moment. This indicates the rated power of the flexible load. This indicates the operating power of the flexible load. This indicates that within the integration interval [tT] p The operating power at any time τ within the range of t], where the operating power can be the actual operating power P of the flexible load at the current time calculated by formula (1). Ld,i It can also be the power value obtained directly.

[0097] In this embodiment, the power deviation between the operating power and the rated power of the flexible load at the second time t is obtained, and based on the second time period T res The estimated recovery deviation energy is obtained by combining a constant factor with the constant factor. This constant factor is related to the slope shape of the recovery process and can be set to, for example, 1 / 2. In one specific embodiment, the estimated recovery deviation energy is calculated as follows:

[0098] (5);

[0099] in, T represents the estimated recovery deviation energy. res Indicates the second duration. This indicates the operating power of the flexible load at the second moment.

[0100] After obtaining the cumulative power deviation energy and the estimated recovery deviation energy, the cumulative support energy of the flexible load at the second moment is obtained based on the sum of the cumulative power deviation energy and the estimated recovery deviation energy. In one specific embodiment, the cumulative support energy is calculated as follows:

[0101] (3);

[0102] in, It represents the accumulated supporting energy.

[0103] Based on this, embodiments of the present invention, when determining the cumulative support energy, not only calculate the cumulative power deviation energy already expended by the flexible load within the target time period, but also include the estimated recovery deviation energy obtained based on the power deviation level at the second moment and the estimated recovery time. This ensures that the decision to trigger recovery is not a passive response waiting until the load energy is completely depleted, but rather a proactive consideration of the energy consumed by the recovery process itself. Therefore, when the flexible load begins to recover, the total energy expenditure of its support and recovery process can be controlled within a preset energy budget threshold, achieving bounded control of the total energy of the support process and preventing the risk of energy budget overruns due to delayed recovery, thereby damaging the load's functionality.

[0104] According to an embodiment of the present invention, when the recovery variable is a first value, the voltage support capability of the flexible load is fully activated, and when the recovery variable is a second value, the voltage support capability is completely deactivated.

[0105] The fully activated state refers to the operating state in which the flexible load's response capability to DC bus voltage deviation is fully released. In this state, the operating power of the flexible load can be adjusted to the maximum extent according to the deviation of the DC bus voltage to provide full voltage support.

[0106] The fully deactivated state refers to an operating state in which the flexible load's response to DC bus voltage deviation is completely shielded. In this state, the flexible load's operating power remains at its rated power and is unaffected by DC bus voltage deviation.

[0107] In this embodiment, the value of the recovery variable is used to determine the activation level of the flexible load's voltage support capability. In one specific implementation, when the recovery variable is adjusted to a first value (e.g., value 1), the flexible load's voltage support capability enters a fully activated state. In this state, the flexible load fully responds to deviations in the DC bus voltage, and its operating power can be adjusted to the maximum permissible range deviating from the rated power to provide the strongest voltage support effect. When the recovery variable is adjusted to a second value (e.g., value 0), the flexible load's voltage support capability enters a completely deactivated state. In this state, the flexible load stops responding to deviations in the DC bus voltage, its operating power remains at the rated power, and it no longer provides voltage support to the grid.

[0108] Based on this, embodiments of the present invention abstract the activation and deactivation of flexible load voltage support capability into explicit internal states by defining the two endpoint state values ​​of the recovery variable. The controller only needs to adjust this single variable to enable and disable the support function, making the control method simple and reliable.

[0109] According to an embodiment of the present invention, when a flexible load operates at rated power for a predetermined first duration, adjusting a recovery variable from a second value back to a first value so that the flexible load restores its voltage support state includes: at the end of the second duration, adjusting the recovery variable to maintain the second value so that the flexible load continues to operate at rated power for the first duration; and when the flexible load operates at rated power for the first duration, within a recovery period equal to the second duration, adjusting the recovery variable to linearly change from the second value to the first value based on a predetermined step size so as to restore the voltage support capability of the flexible load.

[0110] The predetermined step size refers to the fixed value by which the recovery variable increases or decreases within each control cycle. This predetermined step size can be calculated from the total change in the recovery variable and the total duration, in order to achieve linear change in the recovery variable.

[0111] Figure 2 A schematic diagram of the recovery process according to a specific embodiment of the present invention is shown.

[0112] like Figure 2 As shown, in this embodiment, the recovery process can be divided into three consecutive stages, which are performed entirely around the adjustment of the recovery variables.

[0113] The duration of the first phase is the second duration T. res During this phase, the controller periodically adjusts the recovery variable k based on a predetermined step size. Re,i This makes the recovery variable k Re,i The value decreases linearly from the first value (e.g., 1) to the second value (e.g., 0). Combining this with formula (2), it can be seen that as the recovery variable k... Re,iThe linear decrease in voltage deviation term affects the target voltage adjustment factor a. 0i The modulation effect gradually weakens, and the target voltage adjustment factor a 0i Gradually reverting to 1. From formula (3), it can be seen that the reference voltage V of the flexible load... Ld,iRef It then smoothly recovers to the rated voltage V. Ld,iRate Its operating power P SL Smoothly recover from the reduced power support state to the rated power P rate This slope change process avoids increasing the operating power P. SL A step change occurs when the support is withdrawn, thus preventing secondary power surges to the power grid.

[0114] In the second duration T res At the end of the process, restore variable k. Re,i The second value has been reached. At this point, the recovery process enters the second phase. During this phase, the controller adjusts the recovery variable k. Re,i Maintain the second value unchanged so that the flexible load is at its rated power P rate Continuous operation for the first duration T rec Because the recovery variable k Re,i Keeping it at the second value, the target voltage adjustment factor a can be obtained from formula (2). 0i The reference voltage V is constant at 1. From formula (3), we can know that... Ld,iRef Always equal to the rated voltage V Ld,iRate The voltage support capability of the flexible load is completely deactivated, and its operating power P SL Stable at rated power P rate During this rated operation period, flexible loads can operate at full power to compensate for functional deviations accumulated during the support phase due to reduced power operation, thereby minimizing the impact on users. For example, air conditioning systems can cool at full power during this period to reduce indoor temperature increases caused by reduced cooling during the support phase; data centers can obtain stronger computing power during this period to handle the backlog of computing tasks accumulated during the support phase and meet user needs.

[0115] Under flexible load with rated power P rate After running for the first preset duration T rec Afterwards, its original functions have been fully restored. At this point, the recovery process enters the third stage, the duration of which is the same as the second stage, T. res They are equal. During this phase, the controller periodically increments the recovery variable k based on a predetermined step size. Re,i Adjust the value of the recovery variable k. Re,i It increases linearly back to the first value from the second value. This is as the recovery variable k... Re,i The linear increase of the voltage deviation term affects the target voltage adjustment factor a. 0iThe modulation effect gradually recovers, and the target voltage adjustment factor a 0i The flexible load regains its ability to adapt to voltage deviations, and its voltage support capability is gradually activated until it returns to a fully activated state. At this point, the flexible load's support function is re-enabled, awaiting the triggering of the next voltage deviation event.

[0116] Based on this, embodiments of the present invention divide the recovery process into three stages, enabling flexible loads to orderly exit and recover after providing voltage support. The first stage smoothly restores operating power to its rated value, preventing secondary power surges to the grid caused by direct exit. The second stage allows the load to operate continuously at its rated state for a first duration, providing a definite recovery time for functions damaged by reduced power operation during support. The third stage smoothly reactivates voltage support capabilities, preparing for the next participation in grid support. These three stages are interconnected, ensuring that flexible loads can safely exit, fully recover, and become ready again after support ends. This ensures grid stability while preventing long-term damage to the load's own functions, thus making flexible loads feasible as a recyclable grid auxiliary resource.

[0117] This invention also proposes a DC bus voltage support recovery control device based on flexible load.

[0118] Figure 3 A schematic diagram of a DC bus voltage support recovery control device based on a flexible load according to an embodiment of the present invention is shown.

[0119] like Figure 3 As shown, the DC bus voltage support recovery control device 300 based on flexible load includes an adjustment module 310, a determination module 320, and a control module 330.

[0120] The adjustment module 310 is used to adjust the operating power of the flexible load in response to the deviation of the bus voltage of the DC bus from the bus reference voltage, based on the voltage deviation of the bus voltage relative to the bus reference voltage at the first moment, the rated voltage of the flexible load, and the recovery variable, so that the flexible load provides voltage support to the DC bus.

[0121] The determination module 320 is used to determine the cumulative support energy of the flexible load during the target period based on the cumulative power deviation energy caused by voltage support of the flexible load during the target period and the estimated recovery deviation energy required for the flexible load to restore the voltage support state.

[0122] The control module 330 is used to adjust the recovery variable from a first value to a second value when the accumulated support energy is greater than or equal to the energy budget threshold of the flexible load, so that the operating power of the flexible load changes smoothly to the rated power, and when the flexible load operates at the rated power for a preset first time, adjust the recovery variable from the second value back to the first value, so that the flexible load returns to the voltage support state.

[0123] According to an embodiment of the present invention, the determining module 320 includes a first determining submodule, a second determining submodule, and a third determining submodule.

[0124] The first determining submodule is used to obtain the cumulative power deviation energy based on the integration result of the power deviation between the operating power and the rated power within the target time period.

[0125] The second determining submodule is used to obtain the estimated recovery deviation energy based on the power deviation between the operating power and the rated power at the second moment and the second duration.

[0126] The third determination submodule is used to determine the cumulative support energy by summing the cumulative power deviation energy and the estimated recovery deviation energy.

[0127] According to an embodiment of the present invention, the control module 330 includes a first adjustment submodule and a second adjustment submodule.

[0128] The first adjustment submodule is used to adjust the recovery variable to maintain the second value at the end of the second duration so that the flexible load continues to operate at rated power for the first duration.

[0129] The second adjustment submodule is used to adjust the recovery variable linearly from a second value to a first value within a recovery period equal to the second duration, based on a predetermined step size, when the flexible load is operating at rated power for a first duration, so as to restore the voltage support capability of the flexible load.

[0130] According to an embodiment of the present invention, the adjustment module 310 includes a fourth determining submodule and a third adjustment submodule.

[0131] The fourth determination submodule is used to determine the reference voltage for flexible loads based on voltage deviation, rated voltage, and recovery variable.

[0132] The third regulation submodule is used to control the converter of the flexible load according to the reference voltage in order to adjust the operating power of the flexible load.

[0133] According to an embodiment of the present invention, the third adjustment submodule includes a first determining unit and a first correcting unit.

[0134] The first determining unit is used to determine the target voltage adjustment factor based on the voltage deviation, the recovery variable, and the support strength coefficient.

[0135] The first correction unit is used to correct the rated voltage of the flexible load using the target voltage adjustment factor to obtain the reference voltage.

[0136] According to an embodiment of the present invention, the first determining unit includes a first determining subunit, a comparison subunit, a second determining subunit, and a third determining subunit.

[0137] The first determining sub-unit is used to determine the initial voltage adjustment factor based on the voltage deviation, recovery variable, and support strength coefficient.

[0138] The comparison subunit is used to compare the initial voltage adjustment factor with the preset adjustment range to obtain the comparison result. The preset adjustment range is determined by the maximum allowable adjustment ratio of the flexible load voltage.

[0139] The second determining subunit is used to determine the target voltage adjustment factor corresponding to the initial voltage adjustment factor based on the boundary value of the preset adjustment range to which the initial voltage adjustment factor exceeds when the comparison result indicates that the initial voltage adjustment factor exceeds the preset adjustment range.

[0140] The third determining subunit is used to determine the initial voltage adjustment factor as the target voltage adjustment factor when the comparison result indicates that the initial voltage adjustment factor is within the preset adjustment range.

[0141] According to an embodiment of the present invention, the DC bus voltage support recovery control device 300 based on flexible load further includes a terminal voltage acquisition module, a parameter determination module, and a calculation module.

[0142] The terminal voltage acquisition module is used to acquire the terminal voltage of the flexible load.

[0143] The parameter determination module is used to determine the rated voltage, rated power, and load parameters of the flexible load based on the load type of the flexible load. The load parameters include the weighting coefficients for constant power, constant current, and constant impedance components.

[0144] The calculation module is used to calculate the operating power based on the terminal voltage, rated voltage, rated power, and load parameters.

[0145] According to an embodiment of the present invention, the calculation module includes a fifth determination submodule, a sixth determination submodule, a seventh determination submodule, and an eighth determination submodule.

[0146] The fifth determination submodule is used to determine the per-unit voltage value based on the terminal voltage and the rated voltage;

[0147] The sixth determination submodule is used to determine the constant current component based on the per-unit voltage value and the weighting coefficient of the constant current component;

[0148] The seventh determination submodule is used to determine the constant impedance component based on the square of the per-unit voltage value and the weighting coefficient of the constant impedance component.

[0149] The eighth determination submodule is used to obtain the operating power based on the sum of the constant power component, the constant current component and the constant impedance component, wherein the constant power component is determined by the weighting coefficient of the constant power component.

[0150] Any one or more of the modules, submodules, units, and subunits according to embodiments of the present invention, or at least part of the functions of any one or more of them, can be implemented in a single module. Any one or more of the modules, submodules, units, and subunits according to embodiments of the present invention can be implemented by being divided into multiple modules. Any one or more of the modules, submodules, units, and subunits according to embodiments of the present invention can be at least partially implemented as hardware circuits, such as field-programmable gate arrays (FPGAs), programmable logic arrays (PLAs), systems-on-a-chip, systems-on-a-substrate, systems-on-package, application-specific integrated circuits (ASICs), or implemented in hardware or firmware by any other reasonable means of integrating or packaging circuits, or implemented in software, hardware, and firmware, or in any suitable combination of any of these three implementation methods. Alternatively, one or more of the modules, submodules, units, and subunits according to embodiments of the present invention can be at least partially implemented as computer program modules, which, when run, can perform corresponding functions.

[0151] For example, any plurality of the adjustment module 310, determination module 320, and control module 330 can be combined into one module / unit / subunit, or any one of these modules / units / subunits can be split into multiple modules / units / subunits. Alternatively, at least part of the functionality of one or more of these modules / units / subunits can be combined with at least part of the functionality of other modules / units / subunits and implemented in one module / unit / subunit. According to embodiments of the present invention, at least one of the adjustment module 310, determination module 320, and control module 330 can be at least partially implemented as hardware circuitry, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), a system-on-a-chip, a system-on-a-substrate, a system-on-package, an application-specific integrated circuit (ASIC), or any other reasonable means of integrating or packaging the circuitry, or implemented in software, hardware, or firmware, or in any suitable combination of any of these three implementation methods. Alternatively, at least one of the adjustment module 310, the determination module 320, and the control module 330 may be implemented at least partially as a computer program module, which can perform corresponding functions when the computer program module is run.

[0152] It should be noted that the DC bus voltage support recovery control device based on flexible load in the embodiments of the present invention corresponds to the DC bus voltage support recovery control method based on flexible load in the embodiments of the present invention. For a detailed description of the DC bus voltage support recovery control device based on flexible load, please refer to the DC bus voltage support recovery control method based on flexible load, which will not be repeated here.

[0153] Figure 4 A block diagram of an electronic device suitable for implementing a DC bus voltage support recovery control method based on a flexible load, according to an embodiment of the present invention, is shown. Figure 4 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0154] like Figure 4 As shown, an electronic device according to an embodiment of the present invention includes a processor 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory ROM 402 or a program loaded from a storage portion 408 into a random access memory RAM 403. The processor 401 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 401 may also include onboard memory for caching purposes. The processor 401 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0155] RAM 403 stores various programs and data required for the operation of the electronic device. Processor 401, ROM 402, and RAM 403 are interconnected via bus 404. Processor 401 executes various operations of the method flow according to embodiments of the present invention by executing programs in ROM 402 and / or RAM 403. It should be noted that the programs may also be stored in one or more memories other than ROM 402 and RAM 403. Processor 401 may also execute various operations of the method flow according to embodiments of the present invention by executing programs stored in said one or more memories.

[0156] According to embodiments of the present invention, the electronic device may further include an input / output (I / O) interface 405, which is also connected to a bus 404. The electronic device may also include one or more of the following components connected to the input / output (I / O) interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to the input / output (I / O) interface 405 as needed. A removable medium 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 410 as needed so that computer programs read from it can be installed into the storage section 408 as needed.

[0157] According to embodiments of the present invention, the method flow according to embodiments of the present invention can be implemented as a computer software program. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable storage medium, the computer program containing program code for performing the method shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by processor 401, it performs the functions defined in the system of the embodiments of the present invention. According to embodiments of the present invention, the systems, devices, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0158] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into the device / apparatus / system. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of the present invention.

[0159] According to embodiments of the present invention, the computer-readable storage medium may be a non-volatile computer-readable storage medium. Examples include, but are not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the present invention, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0160] For example, according to embodiments of the present invention, a computer-readable storage medium may include the ROM 402 and / or RAM 403 described above and / or one or more memories other than ROM 402 and RAM 403.

[0161] Embodiments of the present invention also include a computer program product comprising a computer program containing program code for performing the methods provided in the embodiments of the present invention. When the computer program product is run on an electronic device, the program code is used to enable the electronic device to implement the DC bus voltage support recovery control method based on flexible load provided in the embodiments of the present invention.

[0162] When the computer program is executed by the processor 401, it performs the functions defined in the system / apparatus of this embodiment of the invention. According to embodiments of the invention, the systems, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0163] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may also be transmitted and distributed in the form of signals over a network medium, and downloaded and installed via communication section 409, and / or installed from removable medium 411. The program code contained in the computer program can be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination thereof.

[0164] According to embodiments of the present invention, program code for executing the computer programs provided in the embodiments of the present invention can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0165] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or pairings fall within the scope of this invention.

[0166] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A DC bus voltage support recovery control method based on flexible load, characterized in that, The voltage support recovery control method includes: In response to a deviation of the DC bus voltage from the bus reference voltage, the operating power of the flexible load is adjusted based on the voltage deviation of the bus voltage relative to the bus reference voltage at a first moment, the rated voltage of the flexible load, and a recovery variable, so that the flexible load provides voltage support to the DC bus, wherein the recovery variable is a first value at the first moment. Based on the cumulative power deviation energy caused by the voltage support of the flexible load during the target time period and the estimated recovery deviation energy required for the flexible load to recover the voltage support state, the cumulative support energy of the flexible load during the target time period is determined, wherein the target time period is determined based on the first time and the second time after the first time. When the accumulated support energy is greater than or equal to the energy budget threshold of the flexible load, the operating power of the flexible load is smoothly changed to the rated power by adjusting the recovery variable from the first value to the second value. When the flexible load operates at the rated power for a predetermined first time, the recovery variable is adjusted back from the second value to the first value, so that the flexible load returns to the voltage support state.

2. The voltage support recovery control method according to claim 1, characterized in that, The cumulative power deviation energy caused by the voltage support of the flexible load during the target time period and the estimated recovery deviation energy required for the flexible load to restore the voltage support state include: The cumulative power deviation energy is obtained based on the integral result of the power deviation between the operating power and the rated power during the target time period; The estimated recovery deviation energy is obtained based on the power deviation between the operating power and the rated power at the second moment and the second duration; wherein, the second duration characterizes the estimated time required for the flexible load to recover from the operating power to the rated power; The sum of the accumulated power deviation energy and the estimated recovery deviation energy is determined as the accumulated support energy.

3. The voltage support recovery control method according to claim 2, characterized in that, When the recovery variable is the first value, the voltage support capability of the flexible load is fully activated; when the recovery variable is the second value, the voltage support capability is completely deactivated.

4. The voltage support recovery control method according to claim 3, characterized in that, When the flexible load operates at the rated power for a predetermined first duration, adjusting the recovery variable from the second value back to the first value so that the flexible load returns to the voltage support state includes: At the end of the second duration, the recovery variable is adjusted to maintain the second value so that the flexible load continues to operate at the rated power for the first duration. When the flexible load operates at the rated power for the first duration, during a recovery period equal to the second duration, the recovery variable is adjusted linearly from the second value to the first value based on a predetermined step size to restore the voltage support capability of the flexible load.

5. The voltage support recovery control method according to claim 1, characterized in that, The step of adjusting the operating power of the flexible load based on the voltage deviation of the bus voltage relative to the bus reference voltage at a first moment, the rated voltage of the flexible load, and the recovery variable includes: A reference voltage for the flexible load is determined based on the voltage deviation, the rated voltage, and the recovery variable. The converter of the flexible load is controlled according to the reference voltage to adjust the operating power of the flexible load.

6. The voltage support recovery control method according to claim 5, characterized in that, The method of controlling the converter of the flexible load according to the reference voltage to adjust the operating power of the flexible load includes: The target voltage adjustment factor is determined based on the voltage deviation, the recovery variable, and the support strength coefficient. The reference voltage is obtained by correcting the rated voltage of the flexible load using the target voltage adjustment factor.

7. The voltage support recovery control method according to claim 6, characterized in that, The step of determining the target voltage adjustment factor based on the voltage deviation, the recovery variable, and the support strength coefficient includes: The initial voltage adjustment factor is determined based on the voltage deviation, the recovery variable, and the support strength coefficient. The initial voltage adjustment factor is compared with the preset adjustment range to obtain the comparison result, wherein the preset adjustment range is determined by the maximum allowable adjustment ratio of the flexible load voltage; If the comparison result indicates that the initial voltage adjustment factor exceeds the preset adjustment range, the target voltage adjustment factor corresponding to the initial voltage adjustment factor is determined according to the boundary value of the preset adjustment range that the initial voltage adjustment factor exceeds. If the comparison result indicates that the initial voltage adjustment factor is within the preset adjustment range, the initial voltage adjustment factor is determined as the target voltage adjustment factor.

8. The voltage support recovery control method according to claim 5, characterized in that, The voltage support recovery control method further includes: Obtain the terminal voltage of the flexible load; Based on the load type of the flexible load, the rated voltage, rated power, and load parameters of the flexible load are determined. The load parameters include a constant power component weighting coefficient, a constant current component weighting coefficient, and a constant impedance component weighting coefficient. The operating power is calculated based on the terminal voltage, the rated voltage, the rated power, and the load parameters.

9. The voltage support recovery control method according to claim 8, characterized in that, The operating power is calculated based on the terminal voltage, the rated voltage, the rated power, and the load parameters, including: The per-unit voltage value is determined based on the terminal voltage and the rated voltage. The constant current component is determined based on the per-unit voltage value and the weighting coefficient of the constant current component; The constant impedance component is determined based on the square of the per-unit voltage value and the weighting coefficient of the constant impedance component; The operating power is obtained based on the sum of the constant power component, the constant current component, and the constant impedance component, wherein the constant power component is determined by the weighting coefficient of the constant power component.

10. A DC bus voltage support recovery control device based on flexible load, applicable to the voltage support recovery control method as described in any one of claims 1 to 9, characterized in that, The voltage support recovery control device includes: An adjustment module is configured to, in response to a deviation of the DC bus voltage from the bus reference voltage, adjust the operating power of the flexible load based on the voltage deviation of the bus voltage relative to the bus reference voltage at a first moment, the rated voltage of the flexible load, and a recovery variable, so that the flexible load provides voltage support to the DC bus, wherein the recovery variable is a first value at the first moment. The determining module is used to determine the cumulative support energy of the flexible load in the target time period based on the cumulative power deviation energy caused by the voltage support of the flexible load in the target time period and the estimated recovery deviation energy required for the flexible load to recover the voltage support state, wherein the target time period is determined based on the first time moment and the second time moment after the first time moment; The control module is configured to, when the accumulated support energy is greater than or equal to the energy budget threshold of the flexible load, adjust the recovery variable from a first value to a second value so that the operating power of the flexible load smoothly changes to the rated power, and when the flexible load operates at the rated power for a preset first time, adjust the recovery variable from the second value back to the first value so that the flexible load returns to the voltage support state.

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