A method for topology construction and operation control of an aerial wind power generation system

Abstract

This invention discloses a topology construction and operation control method for an aerial wind power generation system. The method includes: First, constructing a core electrical structure, the aerial portion of which consists of multiple generator-passive diode rectifier units connected in series, directly generating medium-voltage DC transmission without an onboard boost converter, achieving extreme lightweighting of the aerial platform structurally; Second, adopting a ground parameter adjustment method adapted to this lightweight topology, adjusting the DC voltage of the ground-connected grid converter to match the output characteristics of the aerial passive series circuit, ensuring stable system power output; Finally, through topology steady-state characteristic adaptation analysis, clarifying the system operating parameters and adjustable power boundaries, providing adaptation support for safe topology operation. This invention, starting from topology design, solves the "weight-voltage" paradox faced by existing high-altitude wind energy systems in large-scale applications, while avoiding the problems of insufficient operational stability and low reliability caused by complex topology adaptation.

Description

Technical Field

[0001] This invention relates to the field of renewable energy power generation technology, and in particular to a method for topology construction and operation control of an aerial wind power generation system. Background Technology

[0002] High-altitude wind energy is a clean energy source with great development potential, and its energy density is much higher than that of ground-based wind energy. Among various high-altitude wind energy technologies, the scheme of generating electricity in the air by carrying a generator has attracted much attention because it can continuously and stably output electrical energy. However, when scaling up such systems from kilowatt-level demonstration platforms to megawatt-level commercial applications, a fundamental technical bottleneck is encountered, namely the "weight-voltage" paradox.

[0003] On the one hand, the physical laws of power transmission necessitate the use of medium to high voltages (such as 10kV or higher) to reduce the current in order to minimize the weight of cables transmitting megawatt-level power from thousands of meters above the ground. Using low-voltage transmission would make the weight and cost of the cables unacceptable.

[0004] On the other hand, traditional solutions for voltage boosting on aerial platforms involve using high-power transformers or DC / DC converters. However, these devices are extremely heavy (typically exceeding 1 kg per kilowatt), and for a megawatt system, the booster equipment alone adds several tons of extra load. This contradicts the core requirement of ultra-lightweight design for high-altitude wind energy systems. This inherent "weight-voltage" contradiction severely restricts the development and deployment of large-scale high-altitude wind energy systems. Summary of the Invention

[0005] The purpose of this invention is to provide a topology construction and operation control method for an aerial wind power generation system, which solves the "weight-voltage" paradox encountered by traditional high-altitude wind energy systems in large-scale applications, as well as the resulting problems of complex topology adaptation and low reliability.

[0006] To achieve the above objectives, embodiments of the present invention propose a method for topology construction and operation control of an aerial wind power generation system, comprising:

[0007] A lightweight electrical topology is constructed on an aerial power generation platform, the topology comprising at least two independent wind turbine units, each wind turbine unit comprising a wind turbine, a generator and a passive diode rectifier unit; the DC output terminals of at least two of the wind turbine units are connected in series to form a medium-voltage DC output, wherein the aerial power generation platform does not contain any active power electronic converters or transformers; By adjusting the DC-side voltage of the grid-connected converter located on the ground, the DC current in the series topology is indirectly adjusted, and the output characteristics of each generator unit are synchronously adapted to avoid voltage imbalance or current overload in the topology. Based on the structural parameters of the series topology and the physical parameters of each generator unit, an algebraic relationship describing the topology's operating characteristics is established, and the adaptation relationship between generator speed, DC voltage and current and the topology structure is clarified under normal, blocking, and current-limiting modes. The topology steady-state characteristic adaptation results are embedded into the ground regulation logic to calculate the controllable power boundary of the topology online, and the power is ensured through saturation processing.

[0008] Optionally, the generator is a permanent magnet synchronous generator.

[0009] Optionally, the regulation unit of the grid-connected converter located on the ground adopts a dual closed-loop structure, including a power adaptation outer loop for generating a DC voltage reference value, and a voltage / current regulation inner loop for accurately tracking the voltage reference value to adapt to the passive series characteristics of the topology.

[0010] Optionally, in the topology steady-state characteristic adaptation, when the topology is in normal operating mode, the DC current... With all generator speeds The sum of ground DC voltage The topology adaptation relationship is as follows:

[0011] In the formula, N is the total number of generator units. and For the physical parameters associated with the i-th generator, This refers to the resistance of the DC cable.

[0012] Optionally, the physical parameters and Determined by the following formula:

[0013]

[0014] In the formula, i represents the flux linkage of the i-th generator. Let be the number of pole pairs of the i-th generator. Let π be the stator winding inductance of the i-th generator, and π be the mathematical constant pi.

[0015] Optionally, when the topology is in normal operating mode, the electromagnetic torque of generator i... Determined by the following formula:

[0016] In the formula:

[0017]

[0018]

[0019]

[0020]

[0021] In the formula, Let be the efficiency of the i-th generator-rectifier unit.

[0022] Optionally, when the topology is in normal operating mode, the ground receiving power corresponding to the topology is... It is determined by the following formula:

[0023] In the formula, , , .

[0024] Optionally, when the topology is in normal operating mode, the steady-state adaptive operating point of the topology can be determined by solving the following set of balance equations for mechanical torque and electromagnetic torque:

[0025] In the formula, Let be the mechanical torque of the i-th generator, and be the wind speed. and its own rotation speed The function; Let be the electromagnetic torque of the i-th generator, and be the ground DC voltage. And a function of the speed of all generators.

[0026] Optionally, in the adaptation of topology steady-state characteristics, the operating mode of the topology is determined by the following logical relationships, including: When the topology satisfies the condition and ≤ When the topology is in normal operating mode, the topology output power is adjusted by the ground-connected grid converter. When the topology satisfies the condition When the topology is in blocking mode, the diode rectifier in the air section is reverse biased, the DC current is zero, and the topology cannot generate power. When the topology theoretically emits power under unrestricted conditions Meet the conditions > When the topology is determined to enter current-limiting mode, the output power of the ground-mounted grid-connected converter is limited to its rated maximum value. The topology loses its ability to regulate power.

[0027] Optional, also includes: When the topology enters the blocking mode, the DC current of the topology... Electromagnetic torque of each generator and ground receiving power All are zero; When the topology enters the current-limiting mode, the ground received power Equal to its upper limit value DC voltage passively increased to Its value is determined by the following formula:

[0028] In current limiting mode, DC current for electromagnetic torque By Replace with Perform calculations to adapt to the topology's operating state.

[0029] The embodiments of the present invention have the following beneficial effects: 1) The lightweight topology proposed in this application fundamentally solves the "weight-voltage" paradox of megawatt-level high-altitude wind power systems by connecting the generator-diode rectifier unit in series, making the airborne electrical system extremely lightweight and greatly improving the feasibility and economy of the system.

[0030] 2) This application is a ground parameter matching and adjustment method for lightweight topology configuration. It places all active adjustment components on the ground, making the aerial platform completely passive, which greatly simplifies the topology structure, reduces the failure risk and maintenance difficulty of high-altitude components, and significantly improves the reliability and robustness of the topology.

[0031] 3) This application accurately describes the operating characteristics of the topology under different working conditions and three safe operating modes through topology steady-state characteristic adaptation analysis, providing key parameter support for topology adaptation and adjustment, avoiding topology runaway caused by adjustment exceeding the limit, and improving the operating safety and stability of lightweight topology. Attached Figure Description

[0032] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart illustrating a topology construction and operation control method for an aerial wind power generation system provided in this application embodiment; Figure 2 This is a schematic diagram of the floating platform of the high-altitude wind energy system according to an embodiment of the present invention; Figure 3The core of this invention is a detailed structural diagram of the lightweight series electrical topology; Figure 4 This is a block diagram of the regulating unit structure of a ground-mounted grid-connected converter (GSC) according to an embodiment of the present invention; Figure 5 This is a graph showing the relationship between ground-side power and different wind speeds and DC voltage reference values, obtained through topological steady-state characteristic adaptation analysis in an embodiment of the present invention. Detailed Implementation

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0035] The following describes, with reference to the accompanying drawings, a method for topology construction and operation control of an aerial wind power generation system according to an embodiment of the present invention.

[0036] This embodiment provides a method for topology construction and operation control of an aerial wind power generation system. For example... Figure 1 As shown, the method includes the following steps: S1, Construct a lightweight electrical topology on an airborne power generation platform, the topology including at least two independent wind turbine generator units; connect the DC output terminals of at least two wind turbine generator units in series to form a medium-voltage DC output.

[0037] In this embodiment of the application, the core of step S1 is to construct a lightweight electrical topology on the aerial power generation platform. By reconfiguring the structure, the technical contradiction between "weight and voltage" in the high-altitude power generation system is resolved from the system architecture level, thereby achieving a high-voltage, low-weight system configuration.

[0038] Specifically, in this embodiment, at least two electrically independent wind turbine generator units are installed on an aerial power generation platform. Each wind turbine generator unit includes a wind turbine, a generator, and a passive diode rectifier unit. Preferably, the generator is a permanent magnet synchronous generator. Permanent magnet synchronous generators have advantages such as compact structure, high power density, no need for excitation current, and high efficiency, making them particularly suitable for aerial power generation scenarios where weight and volume are limited.

[0039] In this embodiment, the three-phase AC power generated by each wind turbine unit is rectified into DC power by a corresponding passive diode rectifier unit. The passive diode rectifier unit is a simple bridge rectifier structure, containing no active switching devices or control units, thus avoiding the additional weight associated with the control system and heat dissipation structure. Furthermore, the DC output terminals of at least two wind turbine units are connected in series according to polarity, so that the output voltages of each unit are superimposed on the DC side, thereby forming a medium-voltage DC output. Through this series connection, the voltage level can be increased at the airborne platform without using any boost-type DC / DC converter or transformer.

[0040] It should be noted that the technical concept of this step lies in replacing the traditional "active boost" power electronic solution with a "voltage series superposition" structural design, thereby eliminating the aerial platform's dependence on high-power active power electronic converters and transformers at the source. Since active power electronic converters typically include power switching devices, drive circuits, control units, electromagnetic filter components, and heat dissipation modules, their overall weight, size, and reliability requirements are significant, which is extremely detrimental to the load-bearing capacity and long-term stable operation of the floating platform. This application achieves weight reduction and optimization at the system architecture level by eliminating the aforementioned active conversion stage.

[0041] It should be noted that this step aims to construct an electrical system that fundamentally resolves the "weight-voltage" paradox. For example... Figure 2 and Figure 3 As shown, in a specific 1MW-class embodiment, the system is designed to operate at an altitude of 1500 meters. Aerial floating platform ( Figure 2 It is equipped with N =12 independent wind turbine units.

[0042] like Figure 3 As shown, each unit consists of a wind turbine, a permanent magnet synchronous generator, and a passive, simple diode rectifier. The DC outputs of these 12 units are directly connected in series. Assuming the rated voltage of each generator unit is 760.1V, by connecting them in series, the total output voltage in the air can be accumulated to a medium voltage level of approximately 12kV, thus allowing direct power transmission to the ground via a lightweight medium voltage DC cable.

[0043] In other embodiments, the number of wind turbine generator units can be increased or decreased depending on the target output power and voltage level. For example, when a higher output voltage is required, the number of series units can be increased; when the total power capacity needs to be increased, power expansion can be achieved by adding parallel-to-series branches. The core idea of ​​the embodiments in this application is to use multiple units connected in series to construct a high voltage level, rather than relying on a single large-capacity booster device.

[0044] In summary, this step achieves the direct generation and output of medium-voltage DC by constructing a lightweight electrical topology with multiple units connected in series on the aerial power generation platform. Without introducing any active power electronic converters or transformers, it realizes a high-voltage, low-weight, and high-reliability system architecture, providing a structural foundation for the engineering application of high-altitude wind power generation.

[0045] S2, by adjusting the DC side voltage of the grid-connected converter located on the ground, indirectly adjusts the DC current in the series topology, synchronously adapts to the output characteristics of each generator unit, and avoids voltage imbalance or current overload in the topology.

[0046] In this embodiment, the core of step S2 lies in the fact that, since the airborne power generation platform adopts a completely passive series DC topology, the system lacks any active regulation capability. Therefore, all power regulation, voltage matching, and current control functions are undertaken by the ground-based grid-connected converter. By adjusting the DC-side voltage of the ground-based grid-connected converter, the DC current of the entire series system is indirectly regulated, thereby synchronously adapting to the output characteristics of each generator unit and avoiding problems such as voltage imbalance, current overload, or abnormal off-center load of individual units in the series topology.

[0047] It should be noted that the regulation unit of the ground-based grid-connected converter adopts a dual-closed-loop structure, including a power adaptation outer loop for generating a DC voltage reference value, and a voltage / current regulation inner loop for accurately tracking this voltage reference value to adapt to the passive series characteristics of the topology. As shown in Figure 4, the GSC's regulation unit adopts a typical dual-closed-loop structure to achieve accurate adaptation of the topology's output power.

[0048] The specific adjustment process is as follows: 1) The control objective is to maximize the active power received by the ground. P gnd Tracking power reference value P ref (Adapt to the actual power generation needs of the topology).

[0049] 2) The power regulator acts as the outer loop, performing real-time comparisons. P ref With feedback P gnd The deviation between the two values. This deviation is processed by a PI control module to output a reference value for the DC voltage. v dcref Its core logic is: when the actual power is higher than the reference value, the controller will increase... v dcref Conversely, the power output is reduced to match the power output characteristics of the topology.

[0050] 3) The voltage regulation inner loop and its internal current regulation module, according to... v dcref Based on the measured values ​​of grid voltage and current, a PWM signal is quickly calculated and generated to drive the switching transistor (such as IGCT) of the GSC, thereby adjusting its DC-side voltage. v dc Precise tracking v dcref .

[0051] 4) Because the entire topology is a series loop, the ground... v dc Changes will directly affect the direct current. i dc Size. i dc The change will be uniformly applied to all airborne generators, altering their electromagnetic torque. T ei This, in turn, affects its rotational speed. ω i Ultimately, this results in the topology's total output power. P gnd Stabilize at the new reference value P ref This enables power adaptation between the topology and the power grid.

[0052] In summary, in this embodiment of the application, the DC-side voltage is adjusted by the dual closed-loop structure of the ground-connected converter, thereby indirectly controlling the DC current of the series topology. This, in turn, uniformly adjusts the electromagnetic torque and speed of all generator units, ensuring that the system output power stably tracks the reference value. At the same time, it avoids voltage imbalance and current overload problems, ensuring the stable operation of the aerial passive series system under different wind conditions and grid conditions.

[0053] S3. Based on the structural parameters of the series topology and the physical parameters of each generator unit, establish an algebraic relationship describing the topology's operating characteristics, and clarify the adaptation relationship between the generator speed, DC voltage and current and the topology structure under normal, blocking, and current-limiting modes.

[0054] It should be noted that, in order to enable the ground control unit to perform adaptation tasks accurately and safely, this embodiment of the invention establishes a complete set of parameter adaptation relationships by analyzing the steady-state operating characteristics of the topology. This adaptation relationship can not only determine the steady-state operating point of the topology, but also determine the safe operating mode of the topology.

[0055] Specifically, step S3 is achieved through the following steps: Step S31: Determine the adaptation parameters.

[0056] It should be noted that the key physical parameters in the model and It is directly related to the design parameters of each generator unit, and its derivation formula is as follows:

[0057]

[0058] In the formula, i represents the flux linkage of the i-th generator. Let be the number of pole pairs of the i-th generator. Let π be the stator winding inductance of the i-th generator, and π be the mathematical constant pi.

[0059] Step S32: Establish topological steady-state adaptation relationship.

[0060] It should be noted that, based on the above parameters, the core equation describing the relationship between electrical quantities during normal operation of the topology can be derived.

[0061] 1) DC current matching relationship: describes the DC current of the entire series circuit. Its specific form is:

[0062] In the formula, N is the total number of generator units. and For the physical parameters associated with the i-th generator, This refers to the resistance of the DC cable.

[0063] 2) Electromagnetic torque matching relationship: describes the electromagnetic torque of each generator i. The complete expression for the adaptation relationship with the topology's running state is:

[0064] In the formula:

[0065]

[0066]

[0067]

[0068]

[0069] In the formula, Let be the efficiency of the i-th generator-rectifier unit.

[0070] 3) Ground-received power adaptation relationship: describes the active power received by the ground-based GSC. This is the direct target of topology adaptation adjustment, specifically:

[0071] In the formula, , , .

[0072] Step S33: Solving for the topological steady-state adaptive operating point.

[0073] It should be noted that the steady-state operating point of the topology is defined as the mechanical torque of all generator units. (by wind speed) and its own rotation speed (determined) and electromagnetic torque A state of equilibrium is reached. Therefore, the following can be solved simultaneously: N A system of equations consisting of several equations can determine the steady-state operating point of the topology under given wind speed and ground voltage:

[0074] In the formula, Let be the mechanical torque of the i-th generator, and be the wind speed. and its own rotation speed The function; Let be the electromagnetic torque of the i-th generator, and be the ground DC voltage. And a function of the speed of all generators.

[0075] Step S34: Judgment and application of topology safe operation mode.

[0076] It should be noted that a key application of topology steady-state characteristic adaptation is to enable ground control units to identify and respond to three different safe operating modes of the topology.

[0077] a) Normal operating mode: When the topology meets the conditions and ≤ When the topology is in normal operating mode, the topology output power is adjusted by the ground-connected grid converter. b) Blocking mode: When the topology satisfies the condition When the topology is in blocking mode, the diode rectifier in the air section is reverse biased, the DC current is zero, and the topology cannot generate power. c) Current-limiting mode: When the topology theoretically emits power without limitation Meet the conditions > When the topology is determined to enter current-limiting mode, the output power of the ground-mounted grid-connected converter is limited to its rated maximum value. The topology loses its ability to regulate power.

[0078] Furthermore, it should be noted that when the topology enters the aforementioned blocking mode, the DC current of the topology... Electromagnetic torque of each generator and ground receiving power All are zero; when the topology enters the current-limiting mode, the ground received power is zero. Equal to its upper limit value DC voltage passively increased to Its value is determined by the following formula:

[0079] In current limiting mode, DC current for electromagnetic torque By Replace with Perform calculations to adapt to the topology's operating state.

[0080] S4 embeds the topology steady-state characteristic adaptation results into the ground regulation logic, calculates the controllable power boundary of the topology online, and ensures that the power command is always within the safe domain through saturation processing, preventing the topology from going out of control or entering an unadjustable state.

[0081] It should be noted that the topology steady-state adaptation relationship established in step 103 is ultimately intended to guide and constrain the ground parameter matching adjustment in step 102, ensuring that the topology always operates within its physical feasible domain. This step will elaborate on the specific application of this adaptation relationship.

[0082] In practical implementation, the regulating unit of the ground-mounted grid-connected converter (GSC) receives external dispatch commands or internally generated power reference values ​​P. ref After that, it will not be executed immediately, but will first execute the following judgment and constraint process: 1) Determine the current controllable power range of the topology: The regulating unit quickly calculates the maximum and minimum power that the topology can theoretically emit under the current wind speed by using real-time wind speed data (such as data obtained through sensors or weather forecasts) and solving equations based on the steady-state adaptive operating point established in step S33.

[0083] Power lower limit: This lower limit is typically determined by the boundary of the blocking mode. If the power command is too low, the regulating unit will significantly increase the DC voltage to reduce the power. ,once Exceeding the total electromotive force of the in-flight crew at the current speed (i.e., satisfying) The topology will enter blocking mode, with power suddenly dropping to zero. The minimum power level to avoid entering this mode can be accurately calculated through topology steady-state characteristic adaptation.

[0084] Power limit: This limit is typically determined by the boundary of the current-limiting mode (i.e., the rated power of the GSC). The power command is determined by the physical limits of wind energy resources. If the power command exceeds the maximum power that current wind energy can provide, the command will also be impossible to execute.

[0085] 2) Implementing command constraints and saturation: The regulating unit will use the power reference value to be executed. Compare with the controllable power range calculated above.

[0086] if If the instruction is within this range, it is considered safe and feasible, and the adjustment unit will perform the power adaptation adjustment in step S2 normally.

[0087] if If the power exceeds this range (too high or too low), the regulating unit will saturate the command, meaning the actual power target will be limited to the boundaries of the topology's controllable range. For example, if If the value is higher than the upper limit, the actual execution value will be the upper limit power value.

[0088] 3) Generate adaptation adjustment action: After the above boundary constraints, the final safe power target is sent to the power adaptation outer loop in step S2 to generate the corresponding DC voltage reference value. .

[0089] In one possible embodiment, refer to Figure 5 This figure visually illustrates the power-voltage relationship derived through topological steady-state characteristic adaptation analysis. For any wind speed curve, its vertical axis range represents the topologically controllable power range at that wind speed. The core of step S4 is to ensure that all operations of the regulating unit are confined within the range defined by these curves.

[0090] This step transforms the topological steady-state adaptation relationship into a real-time boundary constraint basis, ensuring the physical feasibility of the adjustment commands and avoiding adjustment saturation, topological oscillation, or runaway caused by command overstepping, thereby greatly improving the operational robustness and stability of the lightweight topology of the entire high-altitude wind energy system.

[0091] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A method for topology construction and operation control of an aerial wind power generation system, characterized in that, include: A lightweight electrical topology is constructed on an aerial power generation platform, the topology comprising at least two independent wind turbine units, each wind turbine unit comprising a wind turbine, a generator and a passive diode rectifier unit; the DC output terminals of at least two of the wind turbine units are connected in series to form a medium-voltage DC output, wherein the aerial power generation platform does not contain any active power electronic converters or transformers; By adjusting the DC-side voltage of the grid-connected converter located on the ground, the DC current in the series topology is indirectly adjusted, and the output characteristics of each generator unit are synchronously adapted to avoid voltage imbalance or current overload in the topology. Based on the structural parameters of the series topology and the physical parameters of each generator unit, an algebraic relationship describing the topology's operating characteristics is established, and the adaptation relationship between generator speed, DC voltage and current and the topology structure is clarified under normal, blocking, and current-limiting modes. The topology steady-state characteristic adaptation results are embedded into the ground regulation logic to calculate the controllable power boundary of the topology online. Saturation processing is used to ensure that the power command is always within the safe domain, preventing the topology from going out of control or entering an unregulatory state.

2. The method according to claim 1, characterized in that, The generator is a permanent magnet synchronous generator.

3. The method according to claim 2, characterized in that, The regulation unit of the grid-connected converter located on the ground adopts a dual closed-loop structure, which includes a power adaptation outer loop for generating a DC voltage reference value, and a voltage / current regulation inner loop for accurately tracking the voltage reference value to adapt to the passive series characteristics of the topology.

4. The method according to claim 3, characterized in that, In topology steady-state characteristic adaptation, when the topology is in normal operating mode, the DC current... With all generator speeds The sum of ground DC voltage The topology adaptation relationship is as follows: In the formula, N is the total number of generator units. and For the physical parameters associated with the i-th generator, This refers to the resistance of a DC cable.

5. The method according to claim 4, characterized in that, The physical parameters and Determined by the following formula: In the formula, i represents the flux linkage of the i-th generator. Let be the number of pole pairs of the i-th generator. Let π be the stator winding inductance of the i-th generator, and π be the mathematical constant pi.

6. The method according to claim 5, characterized in that, When the topology is in normal operating mode, the electromagnetic torque of generator i Determined by the following formula: In the formula: In the formula, Let be the efficiency of the i-th generator-rectifier unit.

7. The method according to claim 6, characterized in that, When the topology is in normal operating mode, the corresponding ground receiving power of the topology It is determined by the following formula: In the formula, , , .

8. The method according to claim 7, characterized in that, When the topology is in normal operating mode, the steady-state adaptive operating point of the topology is determined by solving the following set of balance equations for mechanical torque and electromagnetic torque: In the formula, Let be the mechanical torque of the i-th generator, and be the wind speed. and its own rotation speed The function; Let be the electromagnetic torque of the i-th generator, and be the ground DC voltage. And a function of the speed of all generators.

9. The method according to claim 8, characterized in that, In the adaptation of topology steady-state characteristics, the operating mode of the topology is determined through the following logical relationships: When the topology satisfies the condition and ≤ When the topology is in normal operating mode, the topology output power is adjusted by the ground-connected grid converter. When the topology satisfies the condition When the topology is in blocking mode, the diode rectifier in the air section is reverse biased, the DC current is zero, and the topology cannot generate power. When the topology theoretically emits power under unrestricted conditions Meet the conditions > When the topology is determined to enter current-limiting mode, the output power of the ground-mounted grid-connected converter is limited to its rated maximum value. The topology loses its ability to regulate power.

10. The method of claim 9, characterized in that, Also includes: When the topology enters the blocking mode, the DC current of the topology... Electromagnetic torque of each generator and ground receiving power All are zero; When the topology enters the current-limiting mode, the ground received power Equal to its upper limit value DC voltage passively increased to Its value is determined by the following formula: In current limiting mode, DC current for electromagnetic torque By Replace with Perform calculations to adapt to the topology's operating state.

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