A selection method, device, equipment and medium of a wind turbine generator converter

Abstract

This application discloses a method, apparatus, equipment, and medium for selecting wind turbine converters, belonging to the field of wind power generation technology. The method includes: when selecting the rated capacity of a wind turbine converter in an offshore wind power transmission system, determining the reactive power demand of the diode rectifier in the system; determining the additional reactive power the wind turbine converter needs to bear beyond its own operational output power based on the reactive power demand of the diode rectifier and a preset reactive power compensation coefficient, thus obtaining a target reactive power compensation amount; the preset reactive power compensation coefficient ranges from 0 to 1; determining the apparent capacity of the wind turbine converter based on the target reactive power compensation amount, and determining the rated capacity of the wind turbine converter based on its apparent capacity. This method can optimize the overall cost of the offshore wind power transmission system.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and in particular to a method, apparatus, equipment and medium for selecting a wind turbine converter. Background Technology

[0002] In some wind power transmission systems, to reduce the cost and complexity of the system, diode rectifier units (DRUs) are sometimes chosen as rectifiers at the sending-end stations. After the diode rectifier converts the electricity generated by the wind farm into direct current (DC), it is transmitted to the receiving-end station via long-distance high-voltage DC lines. At the receiving-end station, the electricity generated by the wind farm is integrated into the receiving-end power grid via a modular multilevel converter (MMC).

[0003] Unlike grid-connected phase converters and modular multilevel converters, diode rectifiers are uncontrollable converter devices. During operation, they absorb reactive power, and the amount of reactive power absorbed is closely related to factors such as the grid connection voltage, transformer parameters, and transmission power. Typically, to ensure the safe and stable operation of wind power transmission systems, additional reactive power compensation devices are required at the sending-end converter platform of the wind power transmission system to compensate for the reactive power demand of the diode rectifier. However, traditional fixed reactive power compensation devices are bulky and heavy, significantly increasing the construction and investment costs of the sending-end converter platform. Currently, there is no effective solution to this technical problem. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method, apparatus, equipment, and medium for selecting wind turbine converters, so as to reduce the construction and investment costs required for the sending-end station converter platform, thereby optimizing the overall cost of the offshore wind power transmission system. The specific solution is as follows: To address the aforementioned technical problems, this invention provides a method for selecting a wind turbine converter, comprising: When selecting the rated capacity of the wind turbine converter in the offshore wind power transmission system, the reactive power requirement of the diode rectifier in the offshore wind power transmission system is determined. Based on the reactive power demand of the diode rectifier and the preset reactive power compensation coefficient, the additional reactive power that the wind turbine converter needs to bear besides the power output required to ensure its own operation is determined, and the target reactive power compensation amount is obtained; the preset reactive power compensation coefficient ranges from 0 to 1. The apparent capacity of the wind turbine converter is determined based on the target reactive power compensation amount, and the rated capacity of the wind turbine converter is determined based on the apparent capacity of the wind turbine converter.

[0005] Preferably, determining the reactive power demand of the diode rectifier in the offshore wind power transmission system includes: The reactive power requirement of the diode rectifier is determined based on its structural parameters and operating parameters in the offshore wind power transmission system.

[0006] Preferably, determining the reactive power demand of the diode rectifier based on its structural parameters and operating parameters in the offshore wind power transmission system includes: The DC current of the diode rectifier is determined based on the structural parameters of the diode rectifier, the voltage amplitude of the diode rectifier at the grid connection point, and the voltage value on the DC side. The active power of the diode rectifier is determined based on the DC current of the diode rectifier, and the commutation angle of the diode rectifier is determined based on the active power of the diode rectifier. The reactive power requirement of the diode rectifier is determined based on the commutation angle of the diode rectifier.

[0007] Preferred options also include: Construct a semi-physical simulation platform corresponding to the offshore wind power transmission system; Different combinations of the grid-connected voltage, active power output, and reactive power output at the wind turbine are performed, and the combination results are input one by one to the semi-physical simulation platform. The semi-physical simulation platform then outputs the AC side voltage amplitude and DC side voltage value of the diode rectifier under different input conditions at the wind turbine, thus obtaining the target output set. The maximum reactive power requirement of the diode rectifier is determined based on the target output set.

[0008] Preferably, the construction of the semi-physical simulation platform corresponding to the offshore wind power transmission system includes: Based on the hardware composition and actual operating parameters of the offshore wind power transmission system, a semi-physical simulation platform corresponding to the offshore wind power transmission system is built.

[0009] Preferred options also include: The total reactive power compensation requirement of the wind turbine converter and the diode rectifier is determined based on the maximum reactive power demand of the diode rectifier, and the target total reactive power compensation requirement is obtained. Based on the target total reactive power compensation demand, the cost required when the reactive power to be borne by the wind turbine converter is determined to obtain the first cost, and based on the target total reactive power compensation demand, the cost required when the reactive power to be borne by the converter station reactive power compensation device is determined to obtain the second cost. Under preset power flow stability constraints and preset voltage stability constraints, the preset reactive power compensation coefficient is determined with the objective of minimizing the sum of the first cost and the second cost.

[0010] Preferably, determining the preset reactive power compensation coefficient under preset power flow stability constraints and preset voltage stability constraints, with the objective of minimizing the sum of the first cost and the second cost, includes: Under the preset power flow stability constraint, the range of values ​​corresponding to the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost, thus obtaining the first range of values. Under the preset voltage stability constraint, the range of values ​​corresponding to the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost, thus obtaining the second range of values; Determine the intersection of the first value range and the second value range to obtain the target intersection, and search from the target intersection for the proportional coefficient that minimizes the sum of the first cost and the second cost to obtain the preset reactive power compensation coefficient.

[0011] To address the aforementioned technical problems, the present invention also provides a selection device for a wind turbine converter, comprising: The power determination module is used to determine the reactive power requirement of the diode rectifier in the offshore wind power transmission system when the rated capacity of the wind turbine converter in the offshore wind power transmission system needs to be selected. The compensation calculation module is used to determine the additional reactive power that the wind turbine converter needs to bear in addition to the power output required to ensure its own operation, based on the reactive power demand of the diode rectifier and the preset reactive power compensation coefficient, so as to obtain the target reactive power compensation amount; the preset reactive power compensation coefficient ranges from 0 to 1. The capacity determination module is used to determine the apparent capacity of the wind turbine converter based on the target reactive power compensation amount, and to determine the rated capacity of the wind turbine converter based on the apparent capacity of the wind turbine converter.

[0012] To address the aforementioned technical problems, the present invention also provides a selection device for a wind turbine converter, comprising: Memory, used to store computer programs; A processor is configured to execute the computer program to implement the steps of a method for selecting a wind turbine converter as disclosed above.

[0013] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a wind turbine converter selection method as disclosed above.

[0014] Beneficial Effects: In this invention, when selecting the rated capacity of the wind turbine converter in an offshore wind power transmission system, the reactive power demand of the diode rectifier in the system is first determined. Then, based on the reactive power demand of the diode rectifier and a preset reactive power compensation coefficient, the additional reactive power that the wind turbine converter needs to handle beyond its own operational output is determined, resulting in the target reactive power compensation amount. The preset reactive power compensation coefficient ranges from 0 to 1. Next, the apparent capacity of the wind turbine converter is determined based on the target reactive power compensation amount, and the rated capacity of the wind turbine converter is determined based on its apparent capacity.

[0015] Compared to existing technologies, the method described in this invention is equivalent to adding a portion of the reactive power required by the diode rectifier to the wind turbine converter by pre-setting a reactive power compensation coefficient. In other words, the rated capacity of the wind turbine converter is increased to meet the reactive power requirement of the diode rectifier. With this configuration, there is no need to configure an additional reactive power compensation device in the sending-end converter platform to meet the reactive power requirement of the diode rectifier, or the requirement level for such a device is reduced. This significantly reduces the construction and investment costs of the sending-end converter platform.

[0016] Correspondingly, the wind turbine converter capacity selection device, equipment, and medium provided by the present invention also have the above-mentioned beneficial effects. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a method for selecting a wind turbine converter provided in an embodiment of the present invention; Figure 2This is a structural diagram of an offshore wind power generation system provided in an embodiment of the present invention; Figure 3 This is a structural diagram of a wind turbine converter selection device provided in an embodiment of the present invention; Figure 4 This is a structural diagram of a wind turbine converter selection device provided in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Please see Figure 1 , Figure 1 A flowchart of a method for selecting a wind turbine converter provided in an embodiment of the present invention is shown. The method includes: Step S11: When selecting the rated capacity of the wind turbine converter in the offshore wind power transmission system, determine the reactive power requirement of the diode rectifier in the offshore wind power transmission system. Step S12: Determine the additional reactive power that the wind turbine converter needs to bear in addition to the power output required to ensure its own operation based on the reactive power demand of the diode rectifier and the preset reactive power compensation coefficient, and obtain the target reactive power compensation amount; the preset reactive power compensation coefficient ranges from 0 to 1. Step S13: Determine the apparent capacity of the wind turbine converter based on the target reactive power compensation amount, and determine the rated capacity of the wind turbine converter based on the apparent capacity of the wind turbine converter.

[0021] In this invention, when selecting the rated capacity of the wind turbine converter in an offshore wind power transmission system, it is first necessary to determine the reactive power demand of the diode rectifier in the offshore wind power transmission system; then, based on the reactive power demand of the diode rectifier and the preset reactive power compensation coefficient... To determine the additional reactive power that the wind turbine converter needs to handle beyond its own operating power requirements, the target reactive power compensation amount is obtained. This involves setting a preset reactive power compensation coefficient. It is a coefficient between 0 and 1.

[0022] when This means that the reactive power demand of the diode rectifier is provided by the reactive power compensation device of the converter station in the converter platform of the sending station. The reactive power compensation device of the converter station includes, but is not limited to, adjustable capacitors and static var generators (SVG).

[0023] when This means that the reactive power required by the diode rectifier is provided by the wind turbine converter, and there is no need to configure any converter station reactive power compensation device in the sending-end station converter platform.

[0024] when This means that the reactive power demand of the diode rectifier is jointly borne by the reactive power compensation device of the converter station in the sending-end station converter platform and the wind turbine converter, for example: when This means that the wind turbine converter undertakes 70% of the reactive power demand of the diode rectifier, while the remaining 30% of the reactive power demand of the diode rectifier is provided by the reactive power compensation device of the converter station in the sending-end station converter platform.

[0025] Once the target reactive power compensation amount that the wind turbine converter needs to handle in addition to the power output required for its own operation is determined, the apparent capacity of the wind turbine converter can be determined based on the inherent relationship between its reactive power and apparent capacity. Then, the rated capacity of the wind turbine converter can be determined using Formula 1.

[0026] Formula 1: ; In the formula, The rated capacity of the wind turbine converter. A capacity margin factor greater than 1 This refers to the apparent capacity of the wind turbine converter.

[0027] It should be noted that in this application, the offshore wind power transmission system comprises two parts: a wind power generation system and a transmission system. The wind power generation system refers to the wind turbine, and the transmission system includes a diode rectifier and a converter platform at the sending-end station. Compared to onshore wind power generation systems, offshore wind power transmission systems not only obtain higher-quality wind energy resources but also do not require land resources, thus further enhancing the practical application value of the technical solution described in this application. Furthermore, the construction cost of building a complex converter platform at sea is not only very high but also increases the platform's footprint. However, when the reactive power required by the diode rectifier is added to the wind turbine converter using the method described in this application, there is no need to additionally configure reactive power compensation devices in the converter platform, or the requirement for additional reactive power compensation devices in the converter platform is reduced. This significantly reduces the cost of building an offshore converter platform. In other words, the advantages of the technical solution described in this application in offshore wind power transmission systems are quite obvious.

[0028] Please see Figure 2 , Figure 2 This is a structural diagram of an offshore wind power generation system provided in an embodiment of the present invention. Figure 2 The offshore wind power system shown includes an offshore wind farm 101, a power-to-voltage converter platform 102, an offshore cable 103, an onshore converter station 104, and an onshore AC system 105. The offshore wind farm 101 contains multiple wind turbines (the turbines are located in...). Figure 2 After the wind energy (represented by the letter G) is converted into electrical energy, it is converted into direct current (DC) by the DRU (diode rectifier) ​​in the sending-end converter platform 102. Since the diode rectifier consumes a large amount of reactive power during operation, a reactive power compensation device needs to be added to the sending-end converter platform to ensure the safe and stable operation of the offshore wind power generation system. The rectified DC power is transmitted to the onshore converter station 104 via the offshore cable 103, and then inverted into AC power synchronized with the onshore AC system 105 by the MMC (modular multilevel converter) in the onshore converter station 104, ultimately achieving grid connection with the onshore AC system 105.

[0029] It should be noted that in existing technologies, the rated capacity of wind turbine converters is typically set based on the rated active power of the wind turbine, the reactive power support requirements for grid connection, and conventional design margins. Under this configuration, the reactive power required by the diode rectifier is entirely retained in the sending-end converter platform. This increases the reactive power support pressure on the sending-end converter platform, reduces the flexibility of reactive power resource allocation in offshore wind power transmission systems, and makes it difficult to balance system operational safety and equipment economy. Furthermore, the existing method of selecting wind turbine converter capacity often leads to undersized converters, making it difficult to meet the active power output and reactive power compensation requirements of offshore wind power transmission systems.

[0030] Compared to existing technologies, the method described in this invention is equivalent to adding a portion of the reactive power required by the diode rectifier to the wind turbine converter by pre-setting a reactive power compensation coefficient. In other words, the rated capacity of the wind turbine converter is increased to meet the reactive power requirement of the diode rectifier. With this configuration, there is no need to configure an additional reactive power compensation device in the sending-end converter platform to meet the reactive power requirement of the diode rectifier, or the requirement level for such a device is reduced. This significantly reduces the construction and investment costs of the sending-end converter platform.

[0031] In addition, this method can achieve coordinated optimization of the reactive power compensation required by the diode rectifier for the wind turbine converter and the sending station converter platform. This can avoid the technical problems caused by the conventional selection method of wind turbine converter, which results in the small capacity of the wind turbine converter and difficulty in meeting the active power output and reactive power compensation requirements of the offshore wind power transmission system.

[0032] Based on the above embodiments, this embodiment further explains and optimizes the technical solution. As a preferred implementation, the above step of determining the reactive power demand of the diode rectifier in the offshore wind power transmission system includes: The reactive power requirement of the diode rectifier is determined based on its structural parameters and operating parameters in the offshore wind power transmission system.

[0033] In practical applications, the reactive power demand of a diode rectifier can sometimes be estimated by combining its active power with empirical formulas. However, this method cannot reflect the actual working state of the diode rectifier in the offshore wind power transmission system, and the reactive power demand calculated in this way is not accurate or reliable.

[0034] In this embodiment, to avoid the above-mentioned problems, the reactive power demand of the diode rectifier is determined based on the structural parameters of the diode rectifier and the operating parameters of the diode rectifier in the offshore wind power transmission system, thereby further improving the calculation accuracy of the reactive power demand of the diode rectifier.

[0035] As a preferred embodiment, the above step of determining the reactive power demand of the diode rectifier based on its structural parameters and operating parameters in the offshore wind power transmission system includes: The DC current of the diode rectifier is determined based on its structural parameters, the voltage amplitude at the grid connection point, and the voltage on the DC side. The active power of the diode rectifier is determined based on the DC current of the diode rectifier, and the commutation angle of the diode rectifier is determined based on the active power of the diode rectifier. The reactive power requirement of the diode rectifier is determined based on the commutation angle of the diode rectifier.

[0036] When calculating the reactive power demand of a diode rectifier based on its structural parameters and operating parameters in an offshore wind power transmission system, the first step is to determine the DC current of the diode rectifier using Formula 2. .

[0037] Formula 2: ; In the formula, This refers to the DC current of the diode rectifier. The transformer turns ratio of the diode rectifier. This represents the voltage amplitude of the diode rectifier at the grid connection point. For the transformer leakage inductance of the diode rectifier, Angular frequency, This represents the voltage value on the DC side of the diode rectifier.

[0038] It should be noted that the transformer turns ratio of a diode rectifier and the transformer leakage inductance of the diode rectifier The structural parameters of a diode rectifier include angular frequency. Voltage amplitude of diode rectifier at grid connection point These are the operating parameters of the diode rectifier in the offshore wind power transmission system.

[0039] When the DC current of the diode rectifier is determined Next, the active power of the diode rectifier is calculated according to Formula 3. And determine the active power of the diode rectifier. Next, the commutation angle of the diode rectifier is calculated according to Formula 4. .

[0040] Formula 3: ; In the formula, This refers to the active power of the diode rectifier. This represents the voltage value on the DC side of the diode rectifier. This represents the DC current of the diode rectifier.

[0041] Formula 4: ; In the formula, The commutation angle of the diode rectifier. Angular frequency, For the transformer leakage inductance of the diode rectifier, This refers to the DC current of the diode rectifier. This represents the voltage amplitude of the diode rectifier at the grid connection point. This refers to the transformer turns ratio of a diode rectifier.

[0042] When the commutation angle of the diode rectifier is determined Next, the reactive power requirement of the diode rectifier is calculated according to Formula 5. .

[0043] Formula 5: ; In the formula, The commutation angle of the diode rectifier. This represents the voltage value on the DC side of the diode rectifier. This represents the active power of the diode rectifier.

[0044] When the reactive power demand of the diode rectifier is determined Then, according to Formula 6, the additional reactive power that the wind turbine converter needs to handle besides its own required reactive power output can be calculated, that is, the target reactive power compensation amount. .

[0045] Formula 6: ; In the formula, The target reactive power compensation amount, To preset the reactive power compensation coefficient, This represents the reactive power requirement of the diode rectifier.

[0046] Obviously, the active power of the diode rectifier can be calculated more accurately through the technical solution provided in this embodiment.

[0047] In a preferred embodiment, the above method further includes: Build a semi-physical simulation platform corresponding to the offshore wind power transmission system; Different combinations of the grid-connected voltage, active power output, and reactive power output at the wind turbine are performed, and the combination results are input one by one to the semi-physical simulation platform. This allows the semi-physical simulation platform to run the output diode rectifier and output the AC side voltage amplitude and DC side voltage value corresponding to the different input conditions at the wind turbine, thus obtaining the target output set. The maximum reactive power requirement of the diode rectifier is determined based on the target output set.

[0048] Because the reactive power demand of a diode rectifier is affected by the voltage amplitude at the grid connection point and the DC voltage of the diode rectifier, when the operating conditions at the wind turbine end change—for example, when any parameter of the grid connection voltage, active power output, or reactive power output at the wind turbine end changes—both the AC and DC voltage amplitudes of the diode rectifier will be affected. Therefore, if the reactive power demand of the diode rectifier is calculated solely based on its voltage amplitude at the grid connection point and its DC voltage, and the rated capacity of the wind turbine converter is determined based on this reactive power demand, the accuracy and reliability of the calculated rated capacity of the wind turbine converter will inevitably be affected.

[0049] In this embodiment, to avoid the aforementioned situation, a semi-physical simulation platform corresponding to the offshore wind power transmission system is constructed. After the semi-physical simulation platform is built, the grid-connected voltage, active power output, and reactive power output of the wind turbine are input to the semi-physical simulation platform. This allows the semi-physical simulation platform to output the voltage amplitude of the diode rectifier on the AC side and the voltage value of the diode rectifier on the DC side. In this case, by combining the grid-connected voltage, active power output, and reactive power output of the wind turbine in different ways and inputting the combination results one by one to the semi-physical simulation platform, the semi-physical simulation platform will output the corresponding combinations of AC-side voltage amplitude and DC-side voltage values ​​of the diode rectifier under different input conditions at the wind turbine. This setup is equivalent to having the semi-physical simulation platform simulate all possible values ​​of the output parameters corresponding to the offshore wind power transmission system under different operating conditions. Finally, based on formulas 2, 3, 4 and 5, and according to the output combinations corresponding to the AC side voltage amplitude and DC side voltage values ​​of the diode rectifier under different input conditions at the wind turbine, the maximum reactive power demand of the diode rectifier can be accurately calculated.

[0050] It should be noted that, in this embodiment, the AC side voltage amplitude of the diode rectifier refers to the aforementioned parameters. The DC side voltage value refers to the aforementioned parameters. .

[0051] Obviously, the technical solution provided in this embodiment can avoid underestimating the reactive power demand of the diode rectifier under extreme conditions by only considering a single typical operating condition. This can significantly improve the calculation accuracy when calculating the rated capacity of the wind turbine converter.

[0052] As a preferred implementation, the above steps include: constructing a semi-physical simulation platform corresponding to the offshore wind power transmission system, including: Based on the hardware composition and actual operating parameters of the offshore wind power transmission system, a semi-physical simulation platform corresponding to the offshore wind power transmission system is built.

[0053] When building a semi-physical simulation platform corresponding to an offshore wind power transmission system, the platform is built based on the hardware composition and actual operating parameters of the offshore wind power transmission system.

[0054] Specifically, the first step is to build a hardware-in-the-loop real-time simulation platform, which includes a wind farm end model, a sending-end converter station model, a DC transmission model, and a receiving-end power grid model. Among them, the wind farm end model includes: a wind farm main transformer model, a collector line model, a wind turbine box-type transformer model, a wind turbine generator model, and a wind turbine converter model.

[0055] Specifically, the wind turbine converter is connected via physical hardware control. The controller includes grid-connected control strategies and parameters for both grid-connected and grid-linked wind turbines. All of the above models are consistent with the relevant parameters of the actual wind farm system. The sending-end converter station model includes a step-up transformer model and a diode rectifier model, and the parameters of these two models are consistent with the actual system. The DC transmission model is an equivalent resistance-inductance-capacitance model of a DC cable, and the parameters of this model are also consistent with the actual system. The sending-end converter station model is a modular multilevel converter and its controller, and the parameters of this model are also consistent with the actual system. The receiving-end grid model is a voltage source model with output impedance, and its output impedance is calculated from the short-circuit impedance parameters of the actual system.

[0056] Once the semi-physical simulation platform corresponding to the offshore wind power transmission system is established through the above steps, the platform, by providing wind speed input conditions for the wind turbines, allows different wind turbines within the platform to operate in different active power output states. Furthermore, by setting reactive power commands for different wind turbines, it enables them to operate in different reactive power output states. In this scenario, for the active and reactive power output states of different wind turbines, the voltage amplitudes of the diode rectifier at multiple grid connection points and the multiple voltage values ​​of the diode rectifier on the DC side in the offshore wind power transmission system can be obtained.

[0057] Clearly, the technical solution provided in this embodiment can ensure the accuracy and reliability of building a semi-physical simulation platform corresponding to the offshore wind power transmission system.

[0058] In a preferred embodiment, the above method further includes: The total reactive power compensation requirement of the wind turbine converter and diode rectifier is determined based on the maximum reactive power demand of the diode rectifier, and the target total reactive power compensation requirement is obtained. The cost required to bear the reactive power of the wind turbine converter is determined based on the target total reactive power compensation demand, thus obtaining the first cost. The cost required to bear the reactive power of the converter station reactive power compensation device is determined based on the target total reactive power compensation demand, thus obtaining the second cost. Under preset power flow stability constraints and preset voltage stability constraints, the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost.

[0059] In practical applications, in order to ensure that the offshore wind power transmission system can withstand additional power demand, after calculating the maximum reactive power demand of the diode rectifier, the maximum reactive power demand of the diode rectifier is multiplied by a pre-set reactive power compensation reserve coefficient to determine the total reactive power compensation demand required by the wind turbine converter and the diode rectifier, thereby obtaining the target total reactive power compensation demand.

[0060] Next, based on the target total reactive power compensation demand, the cost required for the reactive power to be borne by the wind turbine converter is determined, resulting in the first cost. Then, based on the target total reactive power compensation demand, the cost required for the reactive power to be borne by the converter station reactive power compensation device is determined, resulting in the second cost. The reactive power to be borne by the converter station reactive power compensation device is the target total reactive power compensation demand minus the reactive power to be borne by the wind turbine converter.

[0061] After obtaining the first cost and the second cost, the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost under preset power flow stability constraints and preset voltage stability constraints. That is, when setting the reactive power compensation coefficient, the preset power flow stability constraints and preset voltage stability constraints must be used as basic constraints. Based on this, the required configuration resources for the sending-end station converter platform and the wind turbine converter can be allocated and adjusted according to the first cost and the second cost, and the preset reactive power compensation coefficient is set based on the resource allocation results between the sending-end station converter platform and the wind turbine converter.

[0062] Specifically, when setting preset power flow stability constraints, based on the static power angle stability limit of the offshore wind power transmission system, the reactive power required by the wind turbine converter should be limited to below the first stability limit, and the reactive power required by the converter station's reactive power compensation device should be limited to below the second stability limit. When setting preset voltage stability constraints, under the combined effect of the reactive power required by the wind turbine converter and the reactive power required by the converter station's reactive power compensation device, the voltage amplitude of the offshore wind power transmission system at the grid connection point should be maintained within the preset allowable voltage deviation range.

[0063] Clearly, by setting the preset reactive power compensation coefficient using the method provided in this embodiment, we can not only ensure the safe operation of the offshore wind power transmission system, but also allocate the configuration resources of the sending-end station converter platform and the wind turbine converter more rationally.

[0064] As a preferred embodiment, the above step, determining the preset reactive power compensation coefficient under preset power flow stability constraints and preset voltage stability constraints with the objective of minimizing the sum of the first cost and the second cost, includes: Under the preset power flow stability constraint, the range of values ​​corresponding to the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost, thus obtaining the first range of values. Under the preset voltage stability constraint, the range of values ​​corresponding to the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost, thus obtaining the second range of values. Determine the intersection of the first and second value ranges to obtain the target intersection, and search from the target intersection for the proportional coefficient that minimizes the sum of the first and second costs to obtain the preset reactive power compensation coefficient.

[0065] When setting the reactive power compensation coefficient, you can first determine the range of values ​​corresponding to the preset reactive power compensation coefficient under the preset power flow stability constraint, with the goal of minimizing the sum of the first cost and the second cost, and obtain the first range of values; then, under the preset voltage stability constraint, determine the range of values ​​corresponding to the preset reactive power compensation coefficient with the goal of minimizing the sum of the first cost and the second cost, and obtain the second range of values.

[0066] When the first value range is obtained, it is equivalent to determining the value range that minimizes the sum of the first cost and the second cost under the preset power flow stability constraint; when the second value range is obtained, it is equivalent to determining the value range that minimizes the sum of the first cost and the second cost under the preset voltage stability constraint.

[0067] Based on this, by finding the intersection of the first and second value ranges, the target intersection is obtained. Then, by performing a one-dimensional search on the target intersection or by performing an analytical solution on the target intersection, the proportional coefficient corresponding to minimizing the sum of the first and second costs can be determined, thereby obtaining the preset reactive power compensation coefficient.

[0068] Obviously, the preset reactive power compensation coefficient can be accurately calculated using the technical solution provided in this embodiment.

[0069] Please see Figure 3 , Figure 3 This is a structural diagram of a wind turbine converter selection device provided in an embodiment of the present invention. The device includes: The power determination module 21 is used to determine the reactive power demand of the diode rectifier in the offshore wind power transmission system when the rated capacity of the wind turbine converter in the offshore wind power transmission system needs to be selected. The compensation calculation module 22 is used to determine the additional reactive power that the wind turbine converter needs to bear in addition to ensuring its own output power, based on the reactive power demand of the diode rectifier and the preset reactive power compensation coefficient, so as to obtain the target reactive power compensation amount; the preset reactive power compensation coefficient has a value range of 0 to 1. The capacity determination module 23 is used to determine the apparent capacity of the wind turbine converter based on the target reactive power compensation amount, and to determine the rated capacity of the wind turbine converter based on the apparent capacity of the wind turbine converter.

[0070] Preferably, the power determination module 21 includes: The power determination submodule is used to determine the reactive power demand of the diode rectifier based on the structural parameters of the diode rectifier and the operating parameters of the diode rectifier in the offshore wind power transmission system.

[0071] Preferably, the power determination submodule includes: The first calculation unit is used to determine the DC current of the diode rectifier based on the structural parameters of the diode rectifier, the voltage amplitude of the diode rectifier at the grid connection point, and the voltage value on the DC side. The second calculation unit is used to determine the active power of the diode rectifier based on the DC current of the diode rectifier, and to determine the commutation angle of the diode rectifier based on the active power of the diode rectifier. The third calculation unit is used to determine the reactive power requirement of the diode rectifier based on the commutation angle of the diode rectifier.

[0072] Preferred options also include: The platform building module is used to build a semi-physical simulation platform corresponding to the offshore wind power transmission system. The combined output module is used to combine the grid-connected voltage, active power output, and reactive power output of the wind turbine in different ways, and input the combination results one by one to the semi-physical simulation platform so that the semi-physical simulation platform can output the AC side voltage amplitude and DC side voltage value of the diode rectifier under different input conditions at the wind turbine to obtain the target output set. The demand determination module is used to determine the maximum reactive power demand of the diode rectifier based on the target output set.

[0073] Preferably, the platform building module includes: The platform building unit is used to build a semi-physical simulation platform corresponding to the offshore wind power transmission system based on the hardware composition and actual operating parameters of the offshore wind power transmission system.

[0074] Preferred options also include: The total amount determination module is used to determine the total reactive power compensation requirement required by the wind turbine converter and the diode rectifier based on the maximum reactive power demand of the diode rectifier, and obtain the target total reactive power compensation requirement. The cost determination module is used to determine the cost required when the reactive power to be borne by the wind turbine converter is based on the target total reactive power compensation demand, to obtain a first cost, and to determine the cost required when the reactive power to be borne by the converter station reactive power compensation device is based on the target total reactive power compensation demand, to obtain a second cost. The coefficient determination module is used to determine the preset reactive power compensation coefficient under preset power flow stability constraints and preset voltage stability constraints, with the goal of minimizing the sum of the first cost and the second cost.

[0075] Preferably, the coefficient determination module includes: The first constraint unit is used to determine the value range corresponding to the preset reactive power compensation coefficient under the preset power flow stability constraint condition, with the goal of minimizing the sum of the first cost and the second cost, and obtain the first value range. The second constraint unit is used to determine the range of values ​​corresponding to the preset reactive power compensation coefficient under the preset voltage stability constraint condition, with the goal of minimizing the sum of the first cost and the second cost, and obtain the second value range. The coefficient determination unit is used to determine the intersection of the first value range and the second value range, obtain the target intersection, and search from the target intersection for the proportional coefficient that minimizes the sum of the first cost and the second cost, thereby obtaining the preset reactive power compensation coefficient. The wind turbine converter selection device provided in this embodiment of the invention has the beneficial effects of the aforementioned wind turbine converter selection method.

[0076] Please see Figure 4 , Figure 4 This is a structural diagram of a wind turbine converter selection device provided in an embodiment of the present invention. The device includes: Memory 31 is used to store computer programs; The processor 32 is configured to execute the computer program to implement the steps of a method for selecting a wind turbine converter as disclosed above.

[0077] The wind power converter selection device provided in this embodiment of the invention has the beneficial effects of the wind turbine converter selection method disclosed above.

[0078] Accordingly, embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a method for selecting a wind turbine converter as disclosed above.

[0079] The computer-readable storage medium provided in this embodiment of the invention has the beneficial effects of the aforementioned method for selecting a wind turbine converter.

[0080] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0081] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0082] The present invention provides a detailed description of the selection method, apparatus, equipment, and medium for a wind turbine converter. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, those skilled in the art will recognize that there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method of selecting a wind turbine generator converter, characterized by, include: When selecting the rated capacity of the wind turbine converter in the offshore wind power transmission system, the reactive power requirement of the diode rectifier in the offshore wind power transmission system is determined. Based on the reactive power demand of the diode rectifier and the preset reactive power compensation coefficient, the additional reactive power that the wind turbine converter needs to bear besides the power output required to ensure its own operation is determined, and the target reactive power compensation amount is obtained; the preset reactive power compensation coefficient ranges from 0 to 1. The apparent capacity of the wind turbine converter is determined based on the target reactive power compensation amount, and the rated capacity of the wind turbine converter is determined based on the apparent capacity of the wind turbine converter.

2. The method of claim 1, wherein, Determining the reactive power demand of the diode rectifier in the offshore wind power transmission system includes: The reactive power requirement of the diode rectifier is determined based on its structural parameters and operating parameters in the offshore wind power transmission system.

3. The method for selecting a wind turbine converter according to claim 2, characterized in that, The determination of the reactive power demand of the diode rectifier based on its structural parameters and operating parameters in the offshore wind power transmission system includes: The DC current of the diode rectifier is determined based on the structural parameters of the diode rectifier, the voltage amplitude of the diode rectifier at the grid connection point, and the voltage value on the DC side. The active power of the diode rectifier is determined based on the DC current of the diode rectifier, and the commutation angle of the diode rectifier is determined based on the active power of the diode rectifier. The reactive power requirement of the diode rectifier is determined based on the commutation angle of the diode rectifier.

4. The method for selecting a wind turbine converter according to claim 3, characterized in that, Also includes: Construct a semi-physical simulation platform corresponding to the offshore wind power transmission system; Different combinations of the grid-connected voltage, active power output, and reactive power output at the wind turbine are performed, and the combination results are input one by one to the semi-physical simulation platform. The semi-physical simulation platform then outputs the AC side voltage amplitude and DC side voltage value of the diode rectifier under different input conditions at the wind turbine, thus obtaining the target output set. The maximum reactive power requirement of the diode rectifier is determined based on the target output set.

5. The method for selecting a wind turbine converter according to claim 4, characterized in that, The construction of a semi-physical simulation platform corresponding to the offshore wind power transmission system includes: Based on the hardware composition and actual operating parameters of the offshore wind power transmission system, a semi-physical simulation platform corresponding to the offshore wind power transmission system is built.

6. The method for selecting a wind turbine converter according to claim 4, characterized in that, Also includes: The total reactive power compensation requirement of the wind turbine converter and the diode rectifier is determined based on the maximum reactive power demand of the diode rectifier, and the target total reactive power compensation requirement is obtained. Based on the target total reactive power compensation demand, the cost required when the reactive power to be borne by the wind turbine converter is determined to obtain the first cost, and based on the target total reactive power compensation demand, the cost required when the reactive power to be borne by the converter station reactive power compensation device is determined to obtain the second cost. Under preset power flow stability constraints and preset voltage stability constraints, the preset reactive power compensation coefficient is determined with the objective of minimizing the sum of the first cost and the second cost.

7. The method for selecting a wind turbine converter according to claim 6, characterized in that, The step of determining the preset reactive power compensation coefficient under preset power flow stability constraints and preset voltage stability constraints, with the objective of minimizing the sum of the first cost and the second cost, includes: Under the preset power flow stability constraint, the range of values ​​corresponding to the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost, thus obtaining the first range of values. Under the preset voltage stability constraint, the range of values ​​corresponding to the preset reactive power compensation coefficient is determined with the goal of minimizing the sum of the first cost and the second cost, thus obtaining the second range of values. Determine the intersection of the first value range and the second value range to obtain the target intersection, and search from the target intersection for the proportional coefficient that minimizes the sum of the first cost and the second cost to obtain the preset reactive power compensation coefficient.

8. A selection device for a wind turbine converter, characterized in that, include: The power determination module is used to determine the reactive power requirement of the diode rectifier in the offshore wind power transmission system when the rated capacity of the wind turbine converter in the offshore wind power transmission system needs to be selected. The compensation calculation module is used to determine the additional reactive power that the wind turbine converter needs to bear in addition to the power output required to ensure its own operation, based on the reactive power demand of the diode rectifier and the preset reactive power compensation coefficient, so as to obtain the target reactive power compensation amount; the preset reactive power compensation coefficient ranges from 0 to 1. The capacity determination module is used to determine the apparent capacity of the wind turbine converter based on the target reactive power compensation amount, and to determine the rated capacity of the wind turbine converter based on the apparent capacity of the wind turbine converter.

9. A selection device for wind turbine converters, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of a method for selecting a wind turbine converter as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of a method for selecting a wind turbine converter as described in any one of claims 1 to 7.

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