Current-limiting control method, device and electronic equipment of power conversion device
Patent Information
- Application Number
- CN202510458082.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2026-10-27
AI Technical Summary
[0004]本申请提供了一种功率变换装置的限流控制方法、装置和电子设备，以解决功率变换装置处于电网电压突变工况下不能安全且稳定运行的问题
[0021]本申请提供的技术方案中，该方法通过响应于电网电压突变，减小功率变换装置的电流环中电流指令值的限幅值，并基于所述限幅值对功率变换装置进行限流控制。本申请中，通过在识别电网发生突变时调整电流环的电流指令值的限幅值，实现对功率变换装置的限流控制，以保证电网电压在任何情况下功率变换装置都能安全且稳定运行。
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Abstract
Description
Technical Field
[0001] This application relates to the field of power electronics technology, and in particular to a current limiting control method, device and electronic equipment for a power conversion device. Background Technology
[0002] With the rapid development of distributed generation technology, large-scale distributed generation systems are being integrated into the power grid. Traditional distributed generation systems lack inertia and damping characteristics in their power conversion devices. Large-scale grid integration reduces the inertia of the power system, easily leading to grid instability or even paralysis. To address this, Virtual Synchronous Generator (VSG) technology has been introduced to endow distributed generation systems with inertia and damping characteristics.
[0003] While the use of VSG can solve the problem of power conversion devices lacking inertia and damping characteristics to some extent, it still cannot guarantee the safe and stable operation of the power conversion device under conditions of sudden changes in grid voltage. Summary of the Invention
[0004] This application provides a current limiting control method, device, and electronic equipment for a power conversion device to solve the problem that the power conversion device cannot operate safely and stably under the condition of sudden changes in grid voltage.
[0005] The first aspect of this application provides a current limiting control method for a power conversion device, the method comprising: in response to a sudden change in grid voltage, reducing a limit value of the current command value in the current loop of the power conversion device, and performing current limiting control on the power conversion device based on the limit value.
[0006] In one feasible implementation, the method further includes: determining a first voltage component of the grid voltage along the d-axis; and determining that a sudden change in the grid voltage has occurred based on the first voltage component and a threshold for a grid voltage change.
[0007] In one feasible implementation, obtaining the voltage change judgment signal based on the first voltage component and the threshold of the power grid change includes: performing low-pass filtering on the first voltage component to obtain the corresponding filtered voltage; calculating the difference between the first voltage component and the corresponding filtered voltage, and comparing the difference with the threshold of the power grid change to determine that the power grid voltage has changed.
[0008] In one feasible implementation, the threshold for the power grid abrupt change includes a first boundary value and a second boundary value that are equal in absolute value; the step of comparing the difference with the threshold for the power grid abrupt change to determine that the power grid voltage has abruptly changed includes: determining that the power grid voltage has abruptly changed if the difference is not between the first boundary value and the second boundary value.
[0009] In one feasible implementation, reducing the current command value limit in the current loop of the power conversion device includes: reducing the current command value limit in the current loop of the power conversion device from a first limit value to a second limit value, wherein the first limit value is the current command value limit when the grid voltage does not change abruptly, and the first limit value is greater than the second limit value.
[0010] In one feasible implementation, reducing the current command value in the current loop of the power conversion device from a first limit value to a second limit value includes: determining the second limit value based on a preset current amplitude adjustment coefficient and the first limit value.
[0011] In one feasible implementation, after the current limiting control of the power conversion device based on the limiting value is performed, the method further includes: in response to the absence of a sudden change in the grid voltage, restoring the limiting value of the current command value from the second limiting value to the first limiting value.
[0012] In one feasible implementation, the limiting reduction time is less than the limiting recovery time, wherein the limiting reduction time is the time it takes for the first limiting value to decrease to the second limiting value, and the limiting recovery time is the time it takes for the second limiting value to recover to the first limiting value.
[0013] In one feasible implementation, the method further includes: obtaining a current reference value and a real-time grid-connected current after limiting the current command value, and calculating the duty cycle modulation voltage; controlling the PWM module to output a drive signal based on the duty cycle modulation voltage to drive the power conversion device.
[0014] A second aspect of this application provides a current limiting control device for a power conversion device, the device comprising: an identification module, configured to reduce the limit value of the current command value in the current loop of the power conversion device in response to a sudden change in grid voltage, and to perform current limiting control on the power conversion device based on the limit value.
[0015] In one feasible implementation, the device further includes an identification module for: acquiring a first voltage component of the grid voltage along the d-axis; and determining whether a sudden change has occurred in the grid voltage based on the first voltage component and a threshold for grid abrupt changes.
[0016] In one feasible implementation, the identification module is specifically used to: perform low-pass filtering on the first voltage component to obtain the corresponding filtered voltage; calculate the difference between the first voltage component and the corresponding filtered voltage, and compare the difference with a threshold for grid voltage change to determine whether the grid voltage has changed.
[0017] In one feasible implementation, the threshold for the power grid abrupt change includes a first boundary value and a second boundary value where the absolute values are equal; the identification module is specifically used to determine that the power grid voltage has abruptly changed when the difference is not between the first boundary value and the second boundary value.
[0018] In one feasible implementation, the current limiting module is further configured to: reduce the current command value limit in the current loop of the power conversion device from a first limit value to a second limit value, wherein the first limit value is the current command value limit when the grid voltage does not change abruptly, and the first limit value is greater than the second limit value.
[0019] Thirdly, embodiments of this application provide an electronic device, including a processor and a memory, wherein the memory stores machine-executable instructions that can be executed by the processor, and the processor executes the machine-executable instructions to implement the current limiting control method of the power conversion device provided above.
[0020] Fourthly, embodiments of this application provide a machine-readable storage medium storing machine-executable instructions. When the machine-executable instructions are invoked and executed by a processor, the machine-executable instructions cause the processor to implement the current limiting control method of the power conversion device provided above.
[0021] In the technical solution provided in this application, the method reduces the current command value limit in the current loop of the power conversion device in response to sudden changes in grid voltage, and performs current limiting control on the power conversion device based on the limit value. In this application, by adjusting the current command value limit in the current loop when a sudden change in grid voltage is detected, current limiting control of the power conversion device is achieved to ensure that the power conversion device can operate safely and stably under any grid voltage conditions. Attached Figure Description
[0022] Figure 1 This is a flowchart illustrating a current limiting control method for a power conversion device in an embodiment of this application.
[0023] Figure 2 This is another flowchart illustrating the current limiting control method of the power conversion device in the embodiments of this application;
[0024] Figure 3 This is a control block diagram for current limiting under sudden voltage changes in an embodiment of this application;
[0025] Figure 4 This is another control block diagram for sudden voltage current limiting in the embodiments of this application;
[0026] Figure 5 This is a schematic diagram illustrating the relationship between the first and second amplitude limiting values in the embodiments of this application;
[0027] Figure 6 This is a schematic diagram of the switching on / off process of the sudden voltage current limiting in the embodiments of this application;
[0028] Figure 7 A schematic diagram of a current limiting control device for a power conversion device provided in an embodiment of this application;
[0029] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation
[0030] This application provides a current limiting control method, device, and electronic equipment for a power conversion device. It suppresses current surges during fault ride-through by reducing the current command value's limiting threshold when the grid voltage undergoes a sudden change. Essentially, it adds voltage surge trigger current limiting logic to identify the voltage surge and change the current limiting ratio of the current command value in the current loop (i.e., change the limiting threshold), thereby suppressing voltage oscillations and overcurrent, and ensuring the safe and stable operation of the power conversion device under grid voltage surge conditions.
[0031] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0032] like Figure 1 As shown in the figure, this application provides an implementation method for a current limiting control method for a power conversion device. The power conversion device is used to connect to the power grid to provide voltage to the grid side or to obtain and store electrical energy from the grid side. The power conversion device can be an inverter, an energy storage converter, or other electronic components that realize power conversion. The method includes the following steps:
[0033] 110. Response to sudden changes in grid voltage.
[0034] In this embodiment, the grid voltage change here is actually one of the identification results generated when identifying whether a sudden change has occurred in the grid voltage. The grid voltage can be understood as the real-time voltage in the grid. Specifically, it is obtained by sampling the grid voltage through a voltage sampling circuit, or it can be obtained by directly sensing and collecting the output voltage on the grid side of the power conversion device through a Hall sensor, thereby obtaining voltage data, which is the grid voltage.
[0035] In one feasible implementation, the voltage information of the power grid is acquired in real time, and two components are obtained through dq conversion: a first voltage component on the d-axis and a second voltage component on the q-axis. Subsequent voltage surge detection and current limiting control are then performed based on the first voltage component.
[0036] Furthermore, in order to achieve accurate and reliable subsequent control, a high-precision voltage sensor can be used, and the acquired voltage signal can be filtered.
[0037] In one feasible implementation, the identification of whether a sudden change in grid voltage has occurred can be achieved by using a preset voltage change detection rule. The preset voltage change detection rule can be a sudden voltage range and a normal voltage range set based on the boundary value of the voltage change, or it can be the boundary value itself.
[0038] The method determines whether a sudden change has occurred by comparing the collected grid voltage with the sudden change interval or boundary value in the voltage sudden change detection rules.
[0039] If the grid voltage is within the abrupt change range (i.e., the grid voltage is less than the lower boundary of the normal voltage range or greater than the upper boundary of the normal voltage range), an abrupt change is determined to have occurred; otherwise, no abrupt change has occurred, and the grid voltage is within the normal operating range.
[0040] 120. Reduce the current command value limit in the current loop of the power conversion device, and perform current limiting control on the power conversion device based on the limit value.
[0041] Specifically, when the control limit value decreases, it can be achieved by a preset current amplitude adjustment coefficient. That is, the current amplitude adjustment coefficient is first multiplied by the first limit value (the limit value when the grid voltage is under normal conditions) to obtain the second limit value (the limit value under sudden change conditions). Then, the second limit value is used as the limit value of the current command value in the current loop. Finally, the current loop command value is current-limited based on the second limit value to obtain the current reference value.
[0042] In this embodiment, besides reducing the limiting value, it can also be maintained, or the limiting value needs to be increased after being reduced. Specifically, in the case of maintaining or increasing, when it is identified that the grid voltage has recovered to a state without sudden change, the limiting value is determined to be the first limiting value. Based on the first limiting value, the current command value in the current loop is limited to obtain the current reference value.
[0043] It should be noted that during the current limiting control of the power conversion device, when the grid voltage does not change abruptly, the first limiting value is used for limiting, which can be understood as the default limiting value under normal conditions. When the voltage changes abruptly, the second limiting value is used for limiting. Specifically, the default limiting value (i.e., the first limiting value) is reduced to the second limiting value to limit the current command value, so as to ensure that the power conversion device can work stably under both abrupt and non-abrupt conditions.
[0044] When limiting the current command value using the first or second limiting value, in order to achieve a fast response and avoid the situation of recurrent overcurrent caused by sudden change of the limiting value, this embodiment adopts a fast-on, slow-off control method for controlling the limiting value. The fast-on, slow-off should be understood as the rapid adjustment of the limiting value to the size of the second limiting value when the voltage changes abruptly, that is, the limiting value is instantly reduced to the second limiting value in time, thereby achieving a fast response to current limiting. During the process of current limiting due to a sudden change, if the voltage recovers to the normal operating range (that is, the voltage does not change abruptly), the second limiting value is slowly increased to the first limiting value. This control method can achieve a fast response to current limiting and avoid the secondary overcurrent caused by the increase of the current limiting value. The execution time of fast control is much shorter than that of slow control. The execution time of fast control is generally one-quarter of the working cycle of the power conversion device, while the execution time of slow control is generally the working cycle of the power grid.
[0045] In this embodiment, current limiting control of the power conversion device is achieved by reducing the current command value in the current loop when a sudden change in grid voltage is detected, so as to ensure that the power conversion device can operate stably under any grid voltage conditions.
[0046] See Figure 2 This is another embodiment of the current limiting control method for the power conversion device provided in this application. The power conversion device can be an inverter or a power conversion system (PCS). The current limiting control method for the power conversion device proposed in this embodiment includes the following steps:
[0047] 210. Determine the first voltage component of the grid voltage along the d-axis.
[0048] In this step, the real-time voltage of the power grid is acquired in real time through a voltage sensor or other means, and then the first voltage component on the d-axis is obtained through dq conversion.
[0049] 220. Based on the first voltage component and the threshold of grid voltage change, determine that a grid voltage change has occurred.
[0050] In this embodiment, the identification of sudden changes in grid voltage can be achieved by setting up a voltage change judgment module. That is, the voltage change judgment module processes the collected grid voltage to obtain a voltage change judgment signal. This voltage change judgment module is set on the input side of the current loop, such as... Figure 3 , 4 As shown.
[0051] The first voltage component u of the grid voltage on the d-axis d The input is low-pass filtered into the voltage change judgment module to obtain the corresponding filtered voltage; the difference between the first voltage component and the corresponding filtered voltage is calculated and compared with the threshold of the power grid change to obtain the voltage change judgment signal, thereby determining whether the power grid voltage has changed.
[0052] Understandably, to ensure accurate identification of voltage surges, the parameters and thresholds of the voltage surge detection module can be appropriately set. The cutoff frequency of the voltage surge detection module can be adjusted according to the periodic voltage fluctuations of the power grid to ensure that sufficiently small voltage surges can be detected. Simultaneously, the threshold settings also need to consider the normal fluctuation range of the power grid voltage to avoid false triggering of current limiting control.
[0053] In one feasible implementation, the voltage change detection module comprises three parts: a filter, a difference calculation module, and a trigger module, such as... Figure 4 As shown, the entire voltage surge detection module is used to identify voltage surges. The filter within it is a low-pass filter, and the T value in the filter... ud The time constant for a first-order low-pass filter is used, and the cutoff frequency is typically set to 5–25 Hz. In the difference module, the first voltage component u of the grid voltage on the d-axis is... d The output of the low-pass filter module is subtracted from the output of the current circuit. The resulting difference is then passed through a trigger module to output a voltage change detection signal. This signal is then sent to the current loop to trigger the current command i in the current loop. gd * and i gq *The current command value is limited. This difference is compared by the trigger module, which outputs two results: one indicating a voltage surge detection, and the other indicating no voltage surge detection. The current command value is limited based on the detection result output by the trigger module. When a surge is detected, the limit value is recorded as i. gdmax * i gdmin * and i gqmax * i gqmin * , where i gdmax * and i gdmin * These are the maximum and minimum amplitude limits of the d-axis when a sudden change occurs, i gqmax * and i gqmin * These are the maximum and minimum amplitude limits on the q-axis when a sudden change occurs; when it is determined that no sudden change has occurred, the amplitude limit is denoted as i. gdmax i gdmin and i gqmax i gqmin , where i gdmax and i gdmin These represent the maximum and minimum amplitude limits of the d-axis when no abrupt change occurs, i gqmax i gqmin These are the maximum and minimum amplitude limits for the q-axis when no sudden change occurs.
[0054] It should be noted that the specific limiting value can be determined by the correspondence between the level of the voltage change judgment signal output by the trigger module and the limiting value. In the voltage change judgment module, low-pass filtering and difference calculation are used to obtain the filtered voltage to determine whether the grid voltage has changed, so as to avoid misjudgment caused by noise signal interference and improve the accuracy of change judgment.
[0055] After obtaining the difference between the first voltage component and the corresponding filter voltage, the difference is output to the trigger module and compared with the threshold of the power grid change, and a voltage change judgment signal is output.
[0056] In this embodiment, the threshold for power grid abrupt change includes a first boundary value and a second boundary value that are equal in absolute value; the step of comparing the difference with the threshold for power grid abrupt change to determine that the power grid voltage has abruptly changed includes: determining that the power grid voltage has abruptly changed when the difference is not between the first boundary value and the second boundary value.
[0057] Specifically, it is determined whether the difference is between the first boundary value and the second boundary value; if yes, a first level is output, which is used to indicate that the grid voltage has not changed abruptly; if no, a second level is output, which is used to indicate that the grid voltage has changed abruptly.
[0058] It should be noted that the first voltage level corresponds to a situation where the grid voltage does not change abruptly, meaning the system is operating within the normal voltage range. The second voltage level corresponds to a situation where the grid voltage changes abruptly, meaning the system is operating outside the normal voltage range.
[0059] 230. Reduce the current command value limit in the current loop of the power conversion device from the first limit value to the second limit value.
[0060] It should be noted that if a sudden change occurs, the current command value limit in the current loop will be quickly reduced from the first limit value to the second limit value using a fast-transfer method. The execution time of the fast-transfer method is determined based on the working cycle of the power conversion device. The first limit value is the current command value limit when the grid voltage does not change, and the first limit value is greater than the second limit value.
[0061] In this embodiment, if no sudden change in the grid voltage is detected, the current limiting value for the current command value of the current loop is determined to be the first limiting value. It should be noted that the first limiting value and the second limiting value are actually two limiting ranges.
[0062] Combination Figure 4 This indicates that when a sudden voltage change is detected, the current loop current limiting value is determined based on the signal output by the trigger module to be the second limiting value, i.e., i. gdmax * i gdmin * and i gqmax * i gqmin * .
[0063] The voltage change detection signal output by the trigger module can be represented as:
[0064]
[0065] Among them, u derr Represents the first voltage component u d The difference between the output of the low-pass filter module and u dthred -u represents the first boundary value that triggers a power grid mutation. dthred u represents the second boundary value that triggers a power grid mutation. dthred The default value can be selected as 0.5u. n u nThis is the rated voltage.
[0066] Assume the maximum current limit of the power conversion device under normal operating conditions is I. max Therefore, the maximum and minimum current limiting values for the d-axis and q-axis in actual operation are i. gdmax i gdmin and i gqmax i gqmin The relationship between the maximum and minimum current limiting values of the d-axis and q-axis is as follows: Figure 5 As shown.
[0067] 240. Current limiting control is applied to the power conversion device based on the second limiting value.
[0068] It should be noted that, after determining that a sudden voltage change has occurred, the limiting values for the d-axis and q-axis in the current loop are selected as follows: Figure 5 i in gdmax * i gdmin * and i gqmax * i gqmin * The maximum current limit value is I max * , where I max * and I max The relationship can be represented as:
[0069]
[0070] Preferably, the adjustment coefficient 1-k is set to 0.5, which is I max * =0.5*I max This relationship setting is primarily for quickly implementing current limiting and, when exiting the second limiting value, avoiding sudden changes in the limiting value that could cause overcurrent again. After current limiting, the process also includes: in response to the absence of a sudden change in the grid voltage, restoring the current command value's limiting value from the second limiting value to the first limiting value. That is, identifying whether a sudden change still exists in the grid voltage after current limiting; if not, restoring the current command value's limiting value in the power conversion device's current loop from the second limiting value to the first limiting value. It is understandable that, in the process of restoring to the first limiting value, the current limiting control process for the power conversion device can be exited first, and then the adjustment coefficient 1-k can be slowly increased until it reaches 1, where this adjustment coefficient is a reduction ratio of the first limiting value.
[0071] Specifically, the control of the first and second threshold values is achieved using a fast-on, slow-off method. When adjusting to the second threshold value, 1-k is rapidly applied, with the application time being one-quarter of the power conversion device's operating cycle. When returning to the first threshold value, 1-k is slowly increased, with the application time being the grid's operating cycle. This allows the voltage and power angle outer loop control to gradually transition to a new steady state based on self-synchronization characteristics. When decreasing the threshold value, the adjustment coefficient 1-k is stepped to 0.5; when returning to the first threshold value, k in 1-k is slowly reduced from 0.5 to 0. Figure 6 As shown.
[0072] In another feasible embodiment, the current loop can also be replaced by a voltage and current dual closed-loop control module, specifically as follows: Figure 4 The module combines a voltage loop and a current loop. A voltage change detection module is added to the input side of the current loop to identify whether a voltage change has occurred in the grid and output a voltage change detection signal. The input of this voltage change detection module is the first voltage component u. d After filtering and comparative analysis by this module, a voltage change judgment signal is output, which is used to trigger the current limiting control process in the current loop. After the voltage change judgment signal is input to the current loop, the specific limit value is determined. This limit value can also be understood as determining the limit range.
[0073] After determining the limiting range of the current command value in the current loop, Figure 4 The voltage loop will display the d-axis voltage component u of the real-time grid voltage. d q-axis voltage component u q With d-axis voltage reference u d * q-axis voltage reference u q * In the PI loop of the differential input voltage loop, after ωC cross-decoupling, the current loop command i is obtained. gd * and i gq * , where ω is the grid frequency and C is the actual capacitance of the power conversion device.
[0074] After receiving the current loop command, the current command value is limited in the current loop by a first or second limiting value. The difference between the measured current and the current reference is then input into the PI element of the current loop. After ωL cross-decoupling, the actual current is superimposed. d and u q Then, the duty cycle modulation voltage e is obtained. d and e qAfter being varied by dq, this voltage is finally input to the PWM module to generate a signal driving the bridge arm. Here, the duty cycle modulation voltage is adjusted by changing the limiting value, thereby controlling the grid-connected voltage of the power conversion device to ensure its stability.
[0075] In summary, the method provided in this application achieves current limiting control by detecting sudden changes in grid voltage and dynamically adjusting the current loop's limiting value. This method can effectively suppress transient and steady-state current and voltage surges in the grid voltage during fault ride-through, ensuring the safe and stable operation of the power conversion device under severe grid voltage fluctuations. Furthermore, this method also offers advantages such as high flexibility and high reliability.
[0076] In addition to the above method, this application also provides a current limiting control device for a power conversion device, see [link to relevant documentation]. Figure 7 The diagram illustrates a current limiting control device for a power conversion device, the device comprising:
[0077] The current limiting control module 720 is used to reduce the current command value in the current loop of the power conversion device in response to the grid voltage, and to perform current limiting control on the power conversion device based on the limit value.
[0078] Optionally, the device further includes an identification module 710, used for:
[0079] Determine the first voltage component of the grid voltage along the d-axis;
[0080] Based on the first voltage component and the threshold for grid voltage change, it is determined that the grid voltage has changed.
[0081] Optionally, the identification module 710 is specifically used for:
[0082] The first voltage component is subjected to low-pass filtering to obtain the corresponding filtered voltage.
[0083] The difference between the first voltage component and the corresponding filtered voltage is calculated, and the difference is compared with the threshold of grid voltage change to determine that the grid voltage has changed.
[0084] Optionally, the threshold for power grid mutation includes a first boundary value and a second boundary value where the absolute values are equal; the identification module 710 is specifically used for:
[0085] If the difference is not located between the first boundary value and the second boundary value, it is determined that the grid voltage has abruptly changed.
[0086] Optionally, the current limiting control module 720 is further configured to:
[0087] The current command value limit in the current loop of the power conversion device is reduced from a first limit value to a second limit value, wherein the first limit value is the current command value limit value when the grid voltage does not change abruptly, and the first limit value is greater than the second limit value.
[0088] Optionally, the current limiting control module 720 is specifically used for:
[0089] The second limiting value is determined based on the preset current amplitude adjustment coefficient and the first limiting value.
[0090] Optionally, the current limiting control module 720 is further configured to:
[0091] In response to the absence of a sudden change in the grid voltage, the current command value's limit is restored from the second limit value to the first limit value.
[0092] Optionally, the limiting reduction time is shorter than the limiting recovery time, wherein the limiting reduction time is the time it takes for the first limiting value to decrease to the second limiting value, and the limiting recovery time is the time it takes for the second limiting value to recover to the first limiting value.
[0093] Optionally, the current limiting control module 720 is further configured to:
[0094] Obtain the current reference value and real-time grid-connected current after limiting the current command value, and calculate the duty cycle modulation voltage;
[0095] The power conversion device is driven by the output drive signal of the duty cycle modulated voltage control PWM module.
[0096] By implementing the aforementioned device, current limiting control of the power conversion device is achieved by adjusting the current command value in the current loop when a sudden change occurs in the power grid. This improves the ride-through performance of the grid-connected power conversion device and ensures that the power conversion device can operate safely and stably under any circumstances.
[0097] See Figure 8 As shown, the electronic device includes a processor 800 and a memory 801. The memory 801 stores machine-executable instructions that can be executed by the processor 800. The processor 800 executes the machine-executable instructions to implement the current limiting control method of the power conversion device described above.
[0098] Furthermore, Figure 8 The electronic device shown also includes a bus 802 and a communication interface 803. The processor 800, the communication interface 803, and the memory 801 are connected via the bus 802.
[0099] The memory 801 may include high-speed random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 803 (which can be wired or wireless), such as the Internet, wide area network, local area network, or metropolitan area network. The bus 802 may be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 8 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.
[0100] The processor 800 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of the processor 800 or by instructions in software form. The processor 800 may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor. The software module can reside in a readily available storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory 801. The processor 800 reads the information from memory 801 and, in conjunction with its hardware, completes the steps of the method described in the foregoing embodiments.
[0101] This application also provides a machine-readable storage medium storing machine-executable instructions. When the machine-executable instructions are called and executed by a processor, the machine-executable instructions cause the processor to implement the current limiting control method of the power conversion device provided in the above embodiments.
[0102] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.
[0103] Furthermore, in the description of the embodiments of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0104] In the description of this application, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0105] Finally, it should be noted that the above embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.
Claims
1. A current limiting control method for a power conversion device, characterized in that, The power conversion device is used to connect to the power grid; the method includes: In response to sudden changes in grid voltage, the current command value in the current loop of the power conversion device is reduced, and current limiting control is performed on the power conversion device based on the reduced value.
2. The current limiting control method for the power conversion device according to claim 1, characterized in that, The method further includes: Determine the first voltage component of the grid voltage along the d-axis; Based on the first voltage component and the threshold for grid voltage change, it is determined that the grid voltage has changed.
3. The current limiting control method for the power conversion device according to claim 2, characterized in that, The step of determining that the grid voltage has changed based on the first voltage component and the threshold for grid voltage change includes: The first voltage component is subjected to low-pass filtering to obtain the corresponding filtered voltage. The difference between the first voltage component and the corresponding filtered voltage is calculated, and the difference is compared with the threshold of grid voltage change to determine that the grid voltage has changed.
4. The current limiting control method for the power conversion device according to claim 3, characterized in that, The threshold for power grid abrupt changes includes a first boundary value and a second boundary value where the absolute values are equal; comparing the difference with the threshold for power grid abrupt changes to determine that the power grid voltage has abruptly changed includes: If the difference is not located between the first boundary value and the second boundary value, it is determined that the grid voltage has abruptly changed.
5. The current limiting control method for the power conversion device according to any one of claims 1-4, characterized in that, The limiting value of the current command value in the current loop of the power conversion device includes: The current command value limit in the current loop of the power conversion device is reduced from a first limit value to a second limit value, wherein the first limit value is the current command value limit value when the grid voltage does not change abruptly, and the first limit value is greater than the second limit value.
6. The current limiting control method for the power conversion device according to claim 5, characterized in that, The step of reducing the current command value in the current loop of the power conversion device from a first limit value to a second limit value includes: The second limiting value is determined based on the preset current amplitude adjustment coefficient and the first limiting value.
7. The current limiting control method for the power conversion device according to claim 6, characterized in that, After performing current limiting control on the power conversion device based on the limiting value, the method further includes: In response to the absence of a sudden change in the grid voltage, the current command value's limit is restored from the second limit value to the first limit value.
8. The current limiting control method for the power conversion device according to claim 7, characterized in that, The amplitude reduction time is less than the amplitude recovery time, wherein the amplitude reduction time is the time it takes for the first amplitude value to decrease to the second amplitude value, and the amplitude recovery time is the time it takes for the second amplitude value to recover to the first amplitude value.
9. The current limiting control method for the power conversion device according to claim 1, characterized in that, The method further includes: Obtain the current reference value and real-time grid-connected current after limiting the current command value, and calculate the duty cycle modulation voltage; The power conversion device is driven by the output drive signal of the duty cycle modulated voltage control PWM module.
10. A current limiting control device for a power conversion device, characterized in that, The device includes: The current limiting control module is used to reduce the current command value limit in the current loop of the power conversion device in response to sudden changes in grid voltage, and to perform current limiting control on the power conversion device based on the limit value.
11. The current limiting control device for the power conversion device according to claim 10, characterized in that, The device further includes an identification module for: Determine the first voltage component of the grid voltage along the d-axis; Based on the first voltage component and the threshold for grid voltage change, it is determined that the grid voltage has changed.
12. The current limiting control device for the power conversion device according to claim 11, characterized in that, The identification module is specifically used for: The first voltage component is subjected to low-pass filtering to obtain the corresponding filtered voltage. The difference between the first voltage component and the corresponding filtered voltage is calculated, and the difference is compared with the threshold of grid voltage change to determine that the grid voltage has changed.
13. The current limiting control device for the power conversion device according to claim 12, characterized in that, The threshold for power grid mutation includes a first boundary value and a second boundary value where the absolute values are equal; the identification module is specifically used for: If the difference is not located between the first boundary value and the second boundary value, it is determined that the grid voltage has abruptly changed.
14. The current limiting control device for the power conversion device according to any one of claims 10-13, characterized in that, The current limiting control module is also used for: The current command value limit in the current loop of the power conversion device is reduced from a first limit value to a second limit value, wherein the first limit value is the current command value limit value when the grid voltage does not change abruptly, and the first limit value is greater than the second limit value.
15. An electronic device, characterized in that, It includes a processor and a memory, the memory storing machine-executable instructions that are executed by the processor, the processor executing the machine-executable instructions to implement the current limiting control method of the power conversion device as described in any one of claims 1-9.