Direct current bus voltage reference value dynamic adjustment method and system

Abstract

The invention provides a direct-current bus voltage reference value dynamic adjustment method and system, and the method comprises the steps: obtaining a direct-current bus real-time voltage value of a power grid, and judging whether the power grid has overvoltage or not based on the direct-current bus real-time voltage value; when overvoltage occurs in the power grid, determining a power grid voltage lifting height value corresponding to the direct-current bus real-time voltage value; and dynamically adjusting a direct-current bus voltage reference value according to the power grid voltage lifting height value. According to the technical scheme provided by the invention, along with the sudden rise of the power grid voltage, the voltage of the grid-side direct current bus can respond quickly and accurately, the problem of over-modulation off-grid is avoided, and the transient oscillation resistance and stable operation capacity of the converter are improved.

Description

Technical Field

[0001] The present application relates to the technical field of DC bus voltage adjustment, and in particular to a method and system for dynamically adjusting a DC bus voltage reference value. Background Art

[0002] For a full-power converter based on a permanent magnet synchronous generator, since the machine-side converter is isolated from the grid by the bus, the fault response plan of the grid-side converter is the focus. When the converter uses a conventional control strategy, a sudden grid surge fault will be limited by the response speed of the current controller, and current shocks will occur during the transient state of voltage rise and recovery, which may cause the busbar to shut down due to overvoltage in severe cases. Therefore, it is urgent to propose a solution that can quickly and accurately adjust the DC bus voltage reference value to ensure the safe and stable operation of the power grid. Summary of the invention

[0003] The present application provides a method and system for dynamically adjusting a DC bus voltage reference value, so as to at least solve the technical problem of shutdown caused by bus overvoltage.

[0004] The first aspect of the present application provides a method for dynamically adjusting a DC bus voltage reference value, the method comprising:

[0005] Acquire a real-time voltage value of a DC bus of a power grid, and determine whether an overvoltage occurs in the power grid based on the real-time voltage value of the DC bus;

[0006] When an overvoltage occurs in the power grid, determining a power grid voltage rise height value corresponding to the real-time voltage value of the DC bus;

[0007] The DC bus voltage reference value is dynamically adjusted according to the grid voltage lift height value.

[0008] Preferably, the determining of the grid voltage rise height value corresponding to the DC bus real-time voltage value comprises:

[0009] When the power grid has an overvoltage, obtaining the power grid voltage at each time within a preset time period;

[0010] The maximum value of the grid voltage is screened out from the grid voltages at each moment within the preset time period, and the screened maximum value of the grid voltage is used as the grid voltage lifting height value.

[0011] Furthermore, the dynamically adjusting the DC bus voltage reference value according to the grid voltage lifting height value includes:

[0012] Obtaining an initial DC bus voltage reference value and a bus voltage adjustment reference value;

[0013] The DC bus voltage reference value to be adjusted is determined according to the initial DC bus voltage reference value, the bus voltage adjustment reference value and the grid voltage lifting height value.

[0014] Furthermore, the DC bus voltage reference value to be adjusted is greater than or equal to a preset DC bus voltage value when the grid voltage is normal and less than or equal to a preset maximum DC bus voltage value allowed for safe operation of the grid voltage.

[0015] Furthermore, the calculation formula of the DC bus voltage reference value to be adjusted is as follows:

[0016]

[0017] In the formula, is the DC bus voltage reference value to be adjusted, U dc is the initial DC bus voltage reference value, k is the bus voltage adjustment coefficient, U max is the grid voltage rise height value, U b Adjust the reference value for the bus voltage.

[0018] A second aspect of the present application provides a system for dynamically adjusting a DC bus voltage reference value, including:

[0019] An acquisition module is used to acquire a real-time voltage value of a DC bus of a power grid, and determine whether an overvoltage occurs in the power grid based on the real-time voltage value of the DC bus;

[0020] A determination module, used for determining a grid voltage rise height value corresponding to the real-time voltage value of the DC bus when an overvoltage occurs in the grid;

[0021] The adjustment module is used to dynamically adjust the DC bus voltage reference value according to the grid voltage lifting height value.

[0022] Preferably, the determining module is further used for:

[0023] When the power grid has an overvoltage, obtaining the power grid voltage at each time within a preset time period;

[0024] The maximum value of the grid voltage is screened out from the grid voltages at each moment within the preset time period, and the screened maximum value of the grid voltage is used as the grid voltage lifting height value.

[0025] Preferably, the adjustment module is also used for:

[0026] Obtaining an initial DC bus voltage reference value and a bus voltage adjustment reference value;

[0027] The DC bus voltage reference value to be adjusted is determined according to the initial DC bus voltage reference value, the bus voltage adjustment reference value and the grid voltage lifting height value.

[0028] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the first aspect is implemented.

[0029] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect of the present application.

[0030] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0031] The present application proposes a method and system for dynamically adjusting a DC bus voltage reference value, the method comprising: obtaining the real-time voltage value of the DC bus of the power grid, and determining whether the power grid has an overvoltage based on the real-time voltage value of the DC bus; when the power grid has an overvoltage, determining the power grid voltage elevation value corresponding to the real-time voltage value of the DC bus; and dynamically adjusting the DC bus voltage reference value according to the power grid voltage elevation value. The technical solution proposed in the present application enables the DC bus voltage on the grid side to respond quickly and accurately as the power grid voltage suddenly rises, and will not be disconnected from the grid due to overmodulation problems, thereby improving the converter's ability to resist transient oscillations and its ability to operate stably.

[0032] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0034] Figure 1 A flowchart of a method for dynamically adjusting a DC bus voltage reference value provided according to an embodiment of the present application;

[0035] Figure 2 The present invention is a structural diagram of a system for dynamically adjusting a DC bus voltage reference value provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0037] The present application proposes a method and system for dynamically adjusting a DC bus voltage reference value, the method comprising: obtaining the real-time voltage value of the DC bus of the power grid, and determining whether the power grid has an overvoltage based on the real-time voltage value of the DC bus; when the power grid has an overvoltage, determining the power grid voltage elevation value corresponding to the real-time voltage value of the DC bus; and dynamically adjusting the DC bus voltage reference value according to the power grid voltage elevation value. The technical solution proposed in the present application enables the DC bus voltage on the grid side to respond quickly and accurately as the power grid voltage suddenly rises, and will not be disconnected from the grid due to overmodulation problems, thereby improving the converter's ability to resist transient oscillations and its ability to operate stably.

[0038] A method and system for dynamically adjusting a DC bus voltage reference value according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0039] Embodiment 1

[0040] Figure 1 Flow chart of a method for dynamically adjusting a DC bus voltage reference value according to an embodiment of the present application, as shown in FIG. Figure 1 As shown, the method includes:

[0041] Step 1: obtaining a real-time voltage value of a DC bus of a power grid, and determining whether an overvoltage occurs in the power grid based on the real-time voltage value of the DC bus;

[0042] Step 2: When an overvoltage occurs in the power grid, determining a power grid voltage rise height value corresponding to the real-time voltage value of the DC bus;

[0043] In the embodiment of the present disclosure, determining the grid voltage rise height value corresponding to the DC bus real-time voltage value includes:

[0044] When the power grid has an overvoltage, obtaining the power grid voltage at each time within a preset time period;

[0045] The maximum value of the grid voltage is screened out from the grid voltages at each moment within the preset time period, and the screened maximum value of the grid voltage is used as the grid voltage lifting height value.

[0046] Step 3: Dynamically adjust the DC bus voltage reference value according to the grid voltage rise height value.

[0047] In the embodiment of the present disclosure, step 3 specifically includes:

[0048] Obtaining an initial DC bus voltage reference value and a bus voltage adjustment reference value;

[0049] The DC bus voltage reference value to be adjusted is determined according to the initial DC bus voltage reference value, the bus voltage adjustment reference value and the grid voltage lifting height value.

[0050] It should be noted that the DC bus voltage reference value to be adjusted is greater than or equal to the DC bus voltage value when the preset grid voltage is normal and less than or equal to the maximum DC bus voltage value allowed for safe operation of the preset grid voltage.

[0051] The calculation formula of the DC bus voltage reference value to be adjusted is as follows:

[0052]

[0053] In the formula, is the DC bus voltage reference value to be adjusted, U dc is the initial DC bus voltage reference value, k is the bus voltage adjustment coefficient (the default value is 1), U max is the grid voltage rise height value, U b Adjust the reference value for the bus voltage (the default is the rated grid voltage value, such as 690V).

[0054] When the grid is overvoltage, the biggest threat to current stability control is overmodulation, because in the overmodulation state, the grid will inject uncontrollable active current into the bus, resulting in increased grid-side current harmonics, unstable DC bus voltage, and affecting active and reactive power control. To solve this problem, the DC bus voltage reference value is dynamically adjusted according to the grid voltage amplitude.

[0055] The rated voltage of DC bus film capacitor is usually 1100V, and 1.15 times overvoltage (1265V) can be tolerated for up to 30 minutes per day without affecting the service life. The grid voltage is 690V, so the DC bus voltage reference value when the grid voltage is normal, that is, the preset DC bus voltage value when the grid voltage is normal, U dcMin Set to 1065V (to ensure normal operation at 1.1 times the grid voltage, 690*1.1*1.4), the maximum DC bus voltage reference value allowed for safe operation is the maximum DC bus voltage value U allowed for safe operation of the preset grid voltage dcMax Set it to 1250V (take a value close to 1265V).

[0056] To sum up, the method for dynamically adjusting the DC bus voltage reference value proposed in this embodiment enables the grid-side DC bus voltage to respond quickly and accurately as the grid voltage suddenly rises, and will not be disconnected from the grid due to overmodulation problems, thereby improving the converter's ability to resist transient oscillations and its ability to operate stably.

[0057] Embodiment 2

[0058] Figure 2 FIG. 1 is a structural diagram of a system for dynamically adjusting a DC bus voltage reference value according to an embodiment of the present application. Figure 2 As shown, the system comprises:

[0059] The acquisition module 100 is used to acquire a real-time voltage value of a DC bus of a power grid, and determine whether an overvoltage occurs in the power grid based on the real-time voltage value of the DC bus;

[0060] A determination module 200 is used to determine a grid voltage rise height value corresponding to the real-time voltage value of the DC bus when an overvoltage occurs in the grid;

[0061] The adjustment module 300 is used to dynamically adjust the DC bus voltage reference value according to the grid voltage lifting height value.

[0062] In the embodiment of the present disclosure, the determining module 200 is further used to:

[0063] When the power grid has an overvoltage, obtaining the power grid voltage at each time within a preset time period;

[0064] The maximum value of the grid voltage is screened out from the grid voltages at each moment within the preset time period, and the screened maximum value of the grid voltage is used as the grid voltage lifting height value.

[0065] In the embodiment of the present disclosure, the adjustment module 300 is further used for:

[0066] Obtaining an initial DC bus voltage reference value and a bus voltage adjustment reference value;

[0067] The DC bus voltage reference value to be adjusted is determined according to the initial DC bus voltage reference value, the bus voltage adjustment reference value and the grid voltage lifting height value.

[0068] The DC bus voltage reference value to be adjusted is greater than or equal to a preset DC bus voltage value when the grid voltage is normal and less than or equal to a preset maximum DC bus voltage value allowed for safe operation of the grid voltage.

[0069] The calculation formula of the DC bus voltage reference value to be adjusted is as follows:

[0070]

[0071] In the formula, is the DC bus voltage reference value to be adjusted, U dc is the initial DC bus voltage reference value, k is the bus voltage adjustment coefficient, U max is the grid voltage rise height value, U b Adjust the reference value for the bus voltage.

[0072] In summary, the DC bus voltage reference value dynamic adjustment system proposed in this embodiment can respond quickly and accurately to the grid-side DC bus voltage as the grid voltage suddenly rises, and will not be disconnected from the grid due to overmodulation problems, thereby improving the converter's ability to resist transient oscillations and its ability to operate stably.

[0073] Embodiment 3

[0074] In order to implement the above embodiments, the present disclosure further proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in Embodiment 1 is implemented.

[0075] Embodiment 4

[0076] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method described in the first embodiment is implemented.

[0077] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0078] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0079] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for dynamically adjusting a DC bus voltage reference value, characterized in that: The method comprises: Acquire a real-time voltage value of a DC bus of a power grid, and determine whether an overvoltage occurs in the power grid based on the real-time voltage value of the DC bus; When an overvoltage occurs in the power grid, determining a power grid voltage rise height value corresponding to the real-time voltage value of the DC bus; The DC bus voltage reference value is dynamically adjusted according to the grid voltage lift height value.

2. The method according to claim 1, characterized in that Determining the grid voltage rise height value corresponding to the DC bus real-time voltage value includes: When the power grid has an overvoltage, obtaining the power grid voltage at each time within a preset time period; The maximum value of the grid voltage is screened out from the grid voltages at each moment within the preset time period, and the screened maximum value of the grid voltage is used as the grid voltage lifting height value.

3. The method according to claim 2, characterized in that The dynamically adjusting the DC bus voltage reference value according to the grid voltage lifting height value includes: Obtaining an initial DC bus voltage reference value and a bus voltage adjustment reference value; The DC bus voltage reference value to be adjusted is determined according to the initial DC bus voltage reference value, the bus voltage adjustment reference value and the grid voltage lifting height value.

4. The method according to claim 3, characterized in that The DC bus voltage reference value to be adjusted is greater than or equal to a preset DC bus voltage value when the grid voltage is normal and less than or equal to a preset maximum DC bus voltage value allowed for safe operation of the grid voltage.

5. The method according to claim 3, characterized in that The calculation formula of the DC bus voltage reference value to be adjusted is as follows: In the formula, is the DC bus voltage reference value to be adjusted, U dc is the initial DC bus voltage reference value, k is the bus voltage adjustment coefficient, U max is the grid voltage rise height value, U b Adjusts the reference value for the bus voltage.

6. A DC bus voltage reference value dynamic adjustment system, characterized in that: The system comprises: An acquisition module is used to acquire a real-time voltage value of a DC bus of a power grid, and determine whether an overvoltage occurs in the power grid based on the real-time voltage value of the DC bus; A determination module, used for determining a grid voltage rise height value corresponding to the real-time voltage value of the DC bus when an overvoltage occurs in the grid; The adjustment module is used to dynamically adjust the DC bus voltage reference value according to the grid voltage lifting height value.

7. The system according to claim 6, characterized in that The determining module is also used for: When the power grid has an overvoltage, obtaining the power grid voltage at each time within a preset time period; The maximum value of the grid voltage is screened out from the grid voltages at each moment within the preset time period, and the screened maximum value of the grid voltage is used as the grid voltage lifting height value.

8. The system according to claim 7, characterized in that The adjustment module is also used for: Obtaining an initial DC bus voltage reference value and a bus voltage adjustment reference value; The DC bus voltage reference value to be adjusted is determined according to the initial DC bus voltage reference value, the bus voltage adjustment reference value and the grid voltage lifting height value.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 5 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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