Wind driven generator shaft voltage analysis method based on broadband equivalent circuit and related device

Abstract

The invention discloses a wind driven generator shaft voltage analysis method based on a broadband equivalent circuit and a related device. The method comprises the following steps: measuring common-mode / differential-mode impedance of a converter port, a cable port and a motor port; obtaining stray capacitance among the stator winding, the stator core, the rotor and the rotating shaft; according to the common-mode / differential-mode impedance of the converter port, the cable port and the motor port and the parasitic capacitance among the stator winding, the stator core, the rotor and the rotating shaft, constructing a converter-cable-motor-containing shaft voltage broadband prediction model; and predicting the broadband distribution characteristics of the shaft voltage of the wind driven generator according to the shaft voltage broadband prediction model. The method and the related device can meet the requirement of accurate prediction of the shaft voltage of the wind driven generator.

Description

Technical Field

[0001] This invention belongs to the technical field of electromagnetic compatibility, motor insulation design and fault diagnosis of wind power generation equipment, and relates to a method and related device for analyzing the shaft voltage of a wind turbine generator based on a broadband equivalent circuit. Background Technology

[0002] During long-term operation, wind turbines commonly face electro-corrosion damage to their main shaft systems. Due to the combined effects of the generator stator windings, high-frequency PWM converters, and structural parasitic parameters, shaft voltage and shaft current are generated between the inner and outer rings of the bearing, leading to pitting, micro-welding, and insulation degradation in the bearing raceways, which seriously affects the reliability and lifespan of the wind turbine.

[0003] The shaft voltage of wind turbine generators exhibits a significant broadband characteristic, primarily determined by the following factors: The PWM switching frequency of the converter is increased to a higher frequency.

[0004] Wind turbine converters typically use PWM switching frequencies of 1 to 20 kHz and contain a large number of high-frequency harmonic components, resulting in shaft voltage distributions spanning from several kHz to hundreds of kHz.

[0005] The parasitic parameters of the motor change significantly with frequency.

[0006] The stator winding impedance, parasitic capacitance to ground, and rotor shaft capacitance to the casing all change significantly with frequency, resulting in large errors in the power frequency model.

[0007] The frequency correlation between common-mode and differential-mode coupling paths is high.

[0008] The common-mode impedance and differential-mode impedance vary greatly across different frequency bands, therefore the calculation of shaft voltage must take into account frequency-related electrical parameters.

[0009] Wideband coupling leads to complex common-mode current paths.

[0010] Within a wide frequency band, converters, cables, motors, and bearings form multiple oscillation paths at different frequency bands, resulting in complex spectral characteristics of shaft voltage.

[0011] Therefore, traditional power frequency equivalent circuits cannot meet the requirements for accurate prediction of wind turbine shaft voltage. It is urgent to construct a wideband equivalent circuit model for the system to achieve accurate quantitative evaluation of the electromagnetic coupling of the converter-cable-motor-bearing system. Summary of the Invention

[0012] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and related apparatus for analyzing the shaft voltage of a wind turbine based on a wideband equivalent circuit. This method and apparatus can meet the requirements for accurate prediction of the shaft voltage of a wind turbine.

[0013] To achieve the above objectives, this invention discloses a method for analyzing the shaft voltage of a wind turbine generator based on a broadband equivalent circuit, comprising: Measure the common-mode / differential-mode impedance of the converter port, cable port, and motor port; Obtain the parasitic capacitance between the stator windings, stator core, rotor, and shaft; Based on the common-mode / differential-mode impedances of the converter port, cable port, and motor port, and the parasitic capacitances between the stator windings, stator core, rotor, and shaft, a broadband prediction model for shaft voltage involving the converter-cable-motor is constructed. The broadband distribution characteristics of wind turbine shaft voltage are predicted based on the aforementioned shaft voltage broadband prediction model.

[0014] Furthermore, a combination of measurement and simulation was used to obtain the parasitic capacitance parameters between the motor stator windings, stator core, and rotor.

[0015] Furthermore, based on the common-mode impedance Z at the motor port... CM Calculate the wideband common-mode impedance of the motor port by measuring the wiring method and its equivalent circuit.

[0016] Furthermore, based on the differential mode impedance of the motor port... Z DM Calculate the differential-mode impedance of the motor port by measuring the wiring and its equivalent circuit.

[0017] Furthermore, the broadband impedance of the single-phase winding is calculated based on the single-phase winding impedance model of the motor.

[0018] Furthermore, the broadband impedance of the three-phase windings is calculated based on the equivalent model of the three-phase windings of the motor.

[0019] This invention discloses a wind turbine shaft voltage analysis system based on a wideband equivalent circuit, comprising: The measurement module is used to measure the common-mode / differential-mode impedance of converter ports, cable ports, and motor ports; The acquisition module is used to acquire the parasitic capacitance between the stator winding, stator core, rotor, and shaft. The module is used to construct a broadband prediction model of shaft voltages involving the converter, cable, and motor based on the common-mode / differential-mode impedances of the converter port, cable port, and motor port, as well as the parasitic capacitances between the stator windings, stator core, rotor, and shaft. The prediction module is used to predict the broadband distribution characteristics of the wind turbine shaft voltage based on the shaft voltage broadband prediction model.

[0020] Furthermore, a combination of measurement and simulation was used to obtain the parasitic capacitance parameters between the motor stator windings, stator core, and rotor.

[0021] This invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the wind turbine shaft voltage analysis method based on a broadband equivalent circuit.

[0022] This invention discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the wind turbine shaft voltage analysis method based on a broadband equivalent circuit.

[0023] The present invention has the following beneficial effects: The wind turbine shaft voltage analysis method and related device based on broadband equivalent circuit described in this invention, in specific operation, constructs a broadband shaft voltage prediction model from hundreds of Hz to hundreds of kHz based on the common-mode / differential-mode impedance of the converter port, cable port, and motor port, and the parasitic capacitance between the stator winding, stator core, rotor, and shaft. The model includes the converter-cable-motor system. Based on the broadband shaft voltage prediction model, the broadband distribution characteristics of the wind turbine shaft voltage are predicted, thus meeting the requirement for accurate prediction of wind turbine shaft voltage. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a topology diagram of a dual-phase three-phase wind turbine system; Figure 2a This is a schematic diagram of the broadband impedance model of a single-phase winding of a motor. Figure 2b This is a schematic diagram of the equivalent model of a three-phase winding; Figure 3a Common-mode impedance of the motor port Z CM Schematic diagram of measurement wiring method Figure 3b Common-mode impedance of the motor port Z CM Equivalent circuit diagram for measuring wiring methods; Figure 4a Differential mode impedance at the motor port Z DM A schematic diagram of the measurement wiring method; Figure 4b Differential mode impedance at the motor port ZDM Equivalent circuit diagram for measuring wiring methods; Figure 5 A schematic diagram of the wiring method for measuring the parasitic capacitance parameter of the converter port to ground (taking phase A as an example); Figure 6 for M A schematic diagram of the basic unit of a multi-conductor transmission line model for cables; Figure 7 for M A schematic diagram of the equivalent node admittance function model for a wire-cable cable; Figure 8 for M Wire and cable 2 M ×2 M A flowchart of the method for extracting elements of the port admittance matrix. Detailed Implementation

[0026] 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, not all, of the embodiments of the present invention. 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.

[0027] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0028] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0029] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0030] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0031] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0034] Example 1 refer to Figure 1 The wind turbine shaft voltage analysis method based on broadband equivalent circuit described in this invention includes the following steps: 1) Establish the wideband equivalent circuit for the inverter port; First, a wideband model of the converter output is performed, including: measuring the parasitic capacitance parameters to ground at each port of the converter; establishing a wideband model of the converter containing the parasitic capacitance parameters; and analyzing the high-frequency components of PWM in conjunction with the IGBT switching process.

[0035] The frequency response of the converter port is determined by measuring the relevant impedance using a wideband scan.

[0036] 2) Establish the wideband equivalent circuit for the motor; according to Figure 3a , Figure 3b , Figure 4a and Figure 4b The measurement method described above yields wideband common-mode impedance and differential-mode impedance data for the motor port. Figure 2a and Figure 2b From the measurement Z CM and Z DM Derive the broadband impedance of single-phase and three-phase windings.

[0037] Considering skin effect and proximity effect M The basic unit of the multi-conductor transmission line model of cable is as follows Figure 6 As shown.

[0038] According to basic circuit theory Figure 6 As shown (2 M+ 1) A port multi-conductor transmission line system can be represented as a system containing m = (2 M +1) × 2 M / 2 = M (2 M The equivalent network y(+1) admittance elements s ), s For Laplace variables, a detailed explanation of this equivalence relationship is as follows: Figure 7 As shown.

[0039] Figure 8 Cable 2 was shown M ×2 M Port admittance matrix Y( s Extraction method for each element: When the port i From AC voltage source U i During excitation, all other ports are connected to the reference port.

[0040] Subsequently, the current flowing into all ports was measured. I j (s) ( j = 1,…, i ,…, 2 M ), to obtain the first i The elements of the row Y i,j ( s ).

[0041] (1) NAFs network y( s The circuit elements of Y and the matrix Y s The relationships between the elements are as follows: (2) The broadband equivalent circuits of converter port impedance, cable impedance, and motor winding impedance are derived using vector matching method and circuit synthesis theory.

[0042] By combining measurement and simulation, the parasitic capacitance parameters between the motor stator winding, stator core, and rotor are obtained, and a shaft voltage analysis model is established.

[0043] Based on the broadband model of converter, motor and bearing, a broadband prediction model of shaft voltage including converter-cable-motor is constructed.

[0044] This invention has the following characteristics: This invention enables integrated broadband modeling of the converter-cable-motor-bearing system; The present invention has a wide frequency range, which can cover the high-frequency components of actual wind turbine PWM; The present invention has high prediction accuracy and can be used for bearing electro-corrosion risk assessment; This invention is applicable to filter design, insulation design, and optimization of shaft voltage suppression schemes.

[0045] Example 2 The wind turbine shaft voltage analysis system based on a wideband equivalent circuit described in this invention includes: The measurement module is used to measure the common-mode / differential-mode impedance of converter ports, cable ports, and motor ports; The acquisition module is used to acquire the parasitic capacitance between the stator winding, stator core, rotor, and shaft. The module is used to construct a broadband prediction model of shaft voltages involving the converter-cable-motor based on the common-mode / differential-mode impedances of the converter port, cable port, and motor port, as well as the parasitic capacitances between the stator windings, stator core, rotor, and shaft. The prediction module is used to predict the broadband distribution characteristics of the wind turbine shaft voltage based on the shaft voltage broadband prediction model.

[0046] In this embodiment, a combination of measurement and simulation is used to obtain the parasitic capacitance parameters between the motor stator winding, stator core, and rotor.

[0047] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0048] Example 3 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the wind turbine shaft voltage analysis method based on a broadband equivalent circuit. For example, the steps include: measuring the common-mode / differential-mode impedance of the converter port, cable port, and motor port; obtaining the parasitic capacitance between the stator winding, stator core, rotor, and shaft; constructing a broadband shaft voltage prediction model including the converter-cable-motor based on the common-mode / differential-mode impedance of the converter port, cable port, and motor port and the parasitic capacitance between the stator winding, stator core, rotor, and shaft; and predicting the broadband distribution characteristics of the wind turbine shaft voltage based on the broadband shaft voltage prediction model. The memory may include main memory, such as high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which can be an industry standard architecture bus, a peripheral component interconnection standard bus, an extended industry standard architecture bus, etc., and the bus can be divided into address bus, data bus, control bus, etc. The memory is used to store programs; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0049] Example 4 A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the wind turbine shaft voltage analysis method based on a broadband equivalent circuit. For example, the steps include: measuring the common-mode / differential-mode impedance of the converter port, cable port, and motor port; obtaining the parasitic capacitance between the stator winding, stator core, rotor, and shaft; constructing a broadband shaft voltage prediction model including the converter-cable-motor based on the common-mode / differential-mode impedance of the converter port, cable port, and motor port and the parasitic capacitance between the stator winding, stator core, rotor, and shaft; and predicting the broadband distribution characteristics of the wind turbine shaft voltage based on the broadband shaft voltage prediction model. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0050] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0051] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0052] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0053] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0054] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0055] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0056] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for analyzing the shaft voltage of a wind turbine generator based on a broadband equivalent circuit, characterized in that, include: Measure the common-mode / differential-mode impedance of the converter port, cable port, and motor port; Obtain the parasitic capacitance between the stator windings, stator core, rotor, and shaft; Based on the common-mode / differential-mode impedances of the converter port, cable port, and motor port, and the parasitic capacitances between the stator windings, stator core, rotor, and shaft, a broadband prediction model for shaft voltage involving the converter-cable-motor is constructed. The broadband distribution characteristics of wind turbine shaft voltage are predicted based on the aforementioned shaft voltage broadband prediction model.

2. The wind turbine shaft voltage analysis method based on broadband equivalent circuit according to claim 1, characterized in that, The parasitic capacitance parameters between the motor stator winding, stator core, and rotor are obtained by combining measurement and simulation.

3. The wind turbine shaft voltage analysis method based on broadband equivalent circuit according to claim 1, characterized in that, Based on the common-mode impedance Z of the motor port CM Calculate the wideband common-mode impedance of the motor port by measuring the wiring method and its equivalent circuit.

4. The wind turbine shaft voltage analysis method based on broadband equivalent circuit according to claim 1, characterized in that, Based on the differential mode impedance of the motor port Z DM Calculate the differential-mode impedance of the motor port by measuring the wiring and its equivalent circuit.

5. The wind turbine shaft voltage analysis method based on broadband equivalent circuit according to claim 1, characterized in that, The broadband impedance of a single-phase winding is calculated based on the single-phase winding impedance model of the motor.

6. The wind turbine shaft voltage analysis method based on broadband equivalent circuit according to claim 1, characterized in that, The broadband impedance of the three-phase windings is calculated based on the equivalent model of the three-phase windings of the motor.

7. A wind turbine shaft voltage analysis system based on a broadband equivalent circuit, characterized in that, include: The measurement module is used to measure the common-mode / differential-mode impedance of converter ports, cable ports, and motor ports; The acquisition module is used to acquire the parasitic capacitance between the stator winding, stator core, rotor, and shaft. The module is used to construct a broadband prediction model of shaft voltages involving the converter, cable, and motor, based on the common-mode / differential-mode impedances of the converter port, cable port, and motor port, as well as the parasitic capacitances between the stator windings, stator core, rotor, and shaft. The prediction module is used to predict the broadband distribution characteristics of the wind turbine shaft voltage based on the shaft voltage broadband prediction model.

8. The wind turbine shaft voltage analysis system based on a wideband equivalent circuit according to claim 7, characterized in that, The parasitic capacitance parameters between the motor stator winding, stator core, and rotor are obtained by combining measurement and simulation.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the wind turbine shaft voltage analysis method based on a broadband equivalent circuit as described in any one of claims 1-6.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the wind turbine shaft voltage analysis method based on a broadband equivalent circuit as described in any one of claims 1-6.

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