Method and system for calculating output and input power of permanent magnet wind generator after demagnetization

Abstract

This invention relates to a method for calculating the input and output power of a permanent magnet wind turbine after demagnetization, and pertains to the field of permanent magnet wind turbine control technology. The method includes: obtaining the first and second average electromagnetic torques of the permanent magnet wind turbine under rated current, both before and after short-circuit demagnetization, and calculating torque loss; dividing the wind speed range of the generator's operation after short-circuit demagnetization into a first wind speed range and a second wind speed range based on the torque loss; calculating the input and output power of the generator in the first and second wind speed ranges based on the torque loss; concatenating the obtained input and output power to obtain the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization; and controlling the permanent magnet wind turbine based on the input and output power curves. This invention solves the problem of maximizing the output power of a permanent magnet wind turbine while ensuring reliability, thereby ensuring maximum power generation.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet wind turbine control technology, and in particular to a method and system for calculating the output and input power of a permanent magnet wind turbine after demagnetization. Background Technology

[0002] Wind energy is a typical clean energy source. my country has abundant wind power resources, and developing wind power generation is not only an essential path to achieving carbon peaking and carbon neutrality, but also a core strategy for building a clean, low-carbon, safe, and efficient energy system. Permanent magnet wind turbines (hereinafter referred to as "generators") have become the preferred solution for wind turbine units due to their high torque density and efficiency. However, the application of permanent magnet materials also brings the risk of irreversible demagnetization (hereinafter referred to as "demagnetization"). After short-circuit demagnetization, the generator can usually continue to operate, but the output power is reduced. Since the amplitude of the back electromotive force fundamental wave decreases after short-circuit demagnetization, the stator current amplitude can be compensated to maximize the output power. This study investigates an iterative calculation method for the generator stator current and rotor-side losses under constant input power. Furthermore, stator current compensation is limited by factors such as winding insulation and grid voltage, especially under full load and near-full load conditions.

[0003] Therefore, it is necessary to solve the problem of maximizing the output power of permanent magnet wind turbines while ensuring reliability, and at the same time, it is also necessary to solve the problem of accurate and rapid calculation of the input and output power of the generator after short-circuit demagnetization. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem that the existing technology cannot effectively solve the problem of maximizing the output power of permanent magnet wind turbine generators while ensuring reliability, and at the same time, it cannot effectively solve the problem of accurate and rapid calculation of the input and output power of the generator after short-circuit demagnetization.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for calculating the output and input power of a permanent magnet wind turbine after demagnetization, comprising:

[0006] Step S1: Obtain the first average electromagnetic torque of the undemagnetized permanent magnet wind turbine under rated current, and obtain the second average electromagnetic torque of the permanent magnet wind turbine under rated current after short-circuit demagnetization. Calculate the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque.

[0007] Step S2: Based on the torque loss, the wind speed range of the generator operation after short-circuit demagnetization is divided into a first wind speed range and a second wind speed range.

[0008] Step S3: Calculate the generator output power in the first wind speed range after short-circuit demagnetization based on the torque loss, while keeping the input power unchanged; calculate the generator input power and output power in the second wind speed range after short-circuit demagnetization based on the torque loss.

[0009] Step S4: Combine the input power of the generator after short-circuit demagnetization in the first and second wind speed ranges, and combine the output power of the generator after short-circuit demagnetization in the first and second wind speed ranges to obtain the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0010] Step S5: Control the permanent magnet wind turbine generator based on the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0011] In one embodiment of the present invention, step S1 calculates the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque, expressed as follows:

[0012] ;

[0013] in, For torque loss, The first average electromagnetic torque, This is the second average electromagnetic torque.

[0014] In one embodiment of the present invention, the method for dividing the wind speed range of the generator operation after short-circuit demagnetization into a first wind speed range and a second wind speed range based on the torque loss in step S2 includes:

[0015] Based on the aforementioned torque loss, the wind speed range during generator operation after short-circuit demagnetization is divided into a first wind speed range. Second wind speed range ,in, To cut into wind speed, Critical wind speed and , For torque loss, This is the rated output power of the generator before demagnetization. To cut off the wind speed.

[0016] In one embodiment of the present invention, in the first wind speed range To maximize the generator's output power, the input power corresponding to each wind speed is... The current remains consistent with that before short-circuit demagnetization, and the generator stator current is fully compensated. The full compensation means that the current amplitude of the stator current is compensated without restriction until the electromagnetic power after compensation plus the various losses of the generator equals the input power.

[0017] In the second wind speed range To ensure that the generator winding temperature does not exceed the insulation limit, limited compensation is applied to the generator stator current. This limited compensation involves compensating for the stator current amplitude, and the compensated stator current does not exceed the rated current before short-circuit demagnetization. At the same time, the generator input power is adjusted to ensure power flow balance.

[0018] In one embodiment of the present invention, step S3, which calculates the generator output power in the first wind speed range after short-circuit demagnetization based on the torque loss, includes:

[0019] First wind speed range Set the generator input current amplitude to The current phase angle is The electromagnetic power of the generator under this current was calculated based on the finite element model of the generator. Rotor-side losses ,in, For torque loss, For wind speed v i The corresponding current amplitude at that time It is an inverse cosine function. For grid connection voltage, For wind speed v i The corresponding back electromotive force, Phase resistance;

[0020] like If the preset conditions are met, the stator-side losses are calculated based on the generator finite element model. The final generator output power is ;

[0021] like If the preset conditions are not met, the generator input current amplitude will be changed to... The current phase angle is ,until If the preset conditions are met, the stator-side losses are calculated based on the generator finite element model. The final generator output power is ,in, For wind speed v i The corresponding input power at that time, In the j-th iteration, when the wind speed is v i The corresponding electromagnetic power at that time In the j-th iteration, when the wind speed is v i The corresponding rotor-side loss, And it is an integer.

[0022] In one embodiment of the present invention, the Meeting the preset conditions is represented as: .

[0023] In one embodiment of the present invention, step S3, which calculates the input power and output power of the generator in the second wind speed range after short-circuit demagnetization based on the torque loss, includes:

[0024] Second wind speed range Based on the finite element model of the generator after short-circuit demagnetization, the amplitude of the generator input current is set to be... The current phase angle is adjusted to The electromagnetic power of the generator under this current was calculated based on the finite element model of the generator. Stator-side losses The final generator output power is ,in, For torque loss, It is an inverse cosine function. For grid connection voltage, For wind speed v i The corresponding back electromotive force, For phase resistance, Rated current;

[0025] Simultaneously, the rotor-side loss of the generator is calculated based on the finite element model of the generator. Adjust the generator input power to ,in, For wind speed v i The corresponding input power at that time.

[0026] To solve the above-mentioned technical problems, the present invention provides a system for calculating the output and input power of a permanent magnet wind turbine after demagnetization, comprising:

[0027] Acquisition module: used to acquire the first average electromagnetic torque of the undemagnetized permanent magnet wind turbine under rated current, and to acquire the second average electromagnetic torque of the permanent magnet wind turbine under rated current after short-circuit demagnetization, and to calculate the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque.

[0028] Division module: used to divide the wind speed range of the generator operation after short-circuit demagnetization into a first wind speed range and a second wind speed range based on the torque loss;

[0029] Calculation module: used to calculate the generator's output power in the first wind speed range after short-circuit demagnetization based on the torque loss, while keeping the input power unchanged; and to calculate the generator's input power and output power in the second wind speed range after short-circuit demagnetization based on the torque loss.

[0030] The splicing module is used to splice the input power of the generator in the first and second wind speed ranges after short-circuit demagnetization, and to splice the output power of the generator in the first and second wind speed ranges after short-circuit demagnetization, so as to obtain the input and output power curves of the generator in the full wind speed range after short-circuit demagnetization.

[0031] Control module: Used to control the permanent magnet wind turbine generator based on the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0032] To solve the above-mentioned technical problems, the present invention provides an electronic 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 above-described method for calculating the output and input power of a permanent magnet wind turbine after demagnetization.

[0033] To solve the above-mentioned technical problems, the present invention provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements the steps of the above-described method for calculating the output and input power of a permanent magnet wind turbine after demagnetization.

[0034] Compared with the prior art, the above-described technical solution of the present invention has the following advantages:

[0035] The method for calculating the output and input power of a permanent magnet wind turbine after demagnetization, as described in this invention, can solve the problem of maximizing the output power of a permanent magnet wind turbine while ensuring reliability, thereby ensuring maximum power generation. It can also solve the problem of accurate and rapid calculation of the input and output power of the generator after short-circuit demagnetization.

[0036] The method of this invention is simple and reliable, and is suitable for large-scale promotion. Attached Figure Description

[0037] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0038] Figure 1 This is a flowchart of the method of the present invention;

[0039] Figure 2 This is a schematic diagram illustrating the relationship between electromagnetic power and critical wind speed in an embodiment of the present invention;

[0040] Figure 3This is a schematic diagram of the generator input and output power curves before and after short-circuit demagnetization in an embodiment of the present invention. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0042] Example 1

[0043] Reference Figure 1 As shown, this invention relates to a method for calculating the output and input power of a permanent magnet wind turbine after demagnetization, comprising:

[0044] Step S1: Obtain the first average electromagnetic torque of the undemagnetized permanent magnet wind turbine under rated current, and obtain the second average electromagnetic torque of the permanent magnet wind turbine under rated current after short-circuit demagnetization. Calculate the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque.

[0045] Step S2: Based on the torque loss, the wind speed range of the generator operation after short-circuit demagnetization is divided into a first wind speed range and a second wind speed range.

[0046] Step S3: Calculate the generator output power in the first wind speed range after short-circuit demagnetization based on the torque loss, while keeping the input power unchanged; calculate the generator input power and output power in the second wind speed range after short-circuit demagnetization based on the torque loss.

[0047] Step S4: Combine the input power of the generator after short-circuit demagnetization in the first and second wind speed ranges, and combine the output power of the generator after short-circuit demagnetization in the first and second wind speed ranges to obtain the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0048] Step S5: Control the permanent magnet wind turbine generator based on the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0049] In this embodiment, input power refers to the mechanical power transferred from the wind turbine to the generator rotor, electromagnetic power refers to the input power minus the generator rotor-side losses and fed into the stator, and output power is the electromagnetic power minus the generator stator-side losses.

[0050] The following is a detailed description of this embodiment:

[0051] Step S1: Calculate the average electromagnetic torque of the permanent magnet wind turbine under rated current. Simultaneously, the average electromagnetic torque of the permanent magnet wind turbine generator under rated current after short-circuit demagnetization is calculated. The torque loss caused by short-circuit demagnetization is calculated based on the first average electromagnetic torque and the second average electromagnetic torque. .

[0052] Step S2: Based on the torque loss, divide the wind speed range of the generator operation after short-circuit demagnetization into a first wind speed range. Second wind speed range ,in, To cut into wind speed, Critical wind speed and , For torque loss, This is the rated output power of the generator before demagnetization. To cut off the wind speed. In the first wind speed range. To maximize the generator's output power, the input power corresponding to each wind speed is... Maintaining consistency with the state before short-circuit demagnetization, the generator stator current is fully compensated. This full compensation means compensating for the stator current amplitude without restriction until the compensated electromagnetic power plus all generator losses equals the input power. Within the second wind speed range... To ensure that the generator winding temperature does not exceed the insulation limit, limited compensation is applied to the generator stator current. This limited compensation involves compensating for the stator current amplitude, and the compensated stator current does not exceed the rated current before short-circuit demagnetization. (If the current exceeds the rated current, the rated current shall be used), and at the same time, the generator input power shall be adjusted (in most cases, reduced) to ensure power flow balance.

[0053] Step S3, the method for calculating the generator output power in the first wind speed range after short-circuit demagnetization based on the torque loss includes: in the first wind speed range Set the generator input current amplitude to The current phase angle is The electromagnetic power of the generator under this current was calculated based on the finite element model of the generator. Rotor-side losses ,in, For torque loss, For wind speed v i The corresponding current amplitude at that time It is an inverse cosine function. For grid connection voltage, For wind speed v i The corresponding back electromotive force, This refers to the phase resistance. It should be noted that by inputting the corresponding current amplitude, current phase angle, and motor speed (mechanical angular velocity) into the generator finite element model (existing software), the rotor-side losses can be output from the generator finite element model. Meanwhile, the finite element model of the generator can calculate the electromagnetic torque, and then multiply the electromagnetic torque by the mechanical angular velocity to obtain the electromagnetic power. .

[0054] like If the preset conditions are met, the current amplitude at this time (i.e., when the generator finite element model is used) is calculated. Stator side loss The final generator output power is ;

[0055] like If the preset conditions are not met, the generator input current amplitude will be changed to... (Equivalent to complete compensation), current phase angle is ,until If the preset conditions are met, the stator-side losses are calculated based on the generator finite element model. The final generator output power is ,in, For wind speed v i The corresponding input power at that time, In the j-th iteration, when the wind speed is v i The corresponding electromagnetic power at that time In the j-th iteration, when the wind speed is v i The corresponding rotor-side loss, And these values ​​are integers. It should be noted that inputting the corresponding current amplitude, current phase angle, and motor speed (mechanical angular velocity) into the generator finite element model will yield the stator-side losses. .

[0056] In this embodiment, The preset conditions to be met are: .

[0057] First wind speed range Since the generator input power remains unchanged before and after short-circuit demagnetization, there is no need to calculate the generator input power.

[0058] Step S3, the method for calculating the input and output power of the generator in the second wind speed range after short-circuit demagnetization based on torque loss includes:

[0059] Second wind speed range Based on the finite element model of the generator after short-circuit demagnetization, the amplitude of the generator input current is set to be... The current phase angle is adjusted to The electromagnetic power of the generator under this current was calculated based on the finite element model of the generator. Stator-side losses The final generator output power is ,in, For torque loss, It is an inverse cosine function. For grid connection voltage, For wind speed v i The corresponding back electromotive force, For phase resistance, The rated current is used; simultaneously, the rotor-side losses of the generator are calculated based on the generator finite element model. Adjust the generator input power to ,in, For wind speed v i The corresponding input power at that time.

[0060] Step S4: Combine the input power of the generator after short-circuit demagnetization in the first and second wind speed ranges, and combine the output power of the generator after short-circuit demagnetization in the first and second wind speed ranges to obtain the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0061] The following is a detailed explanation of this embodiment through a specific case:

[0062] S1: Suppose that the rated current of a permanent magnet wind turbine generator before short-circuit demagnetization is 9966A and the average electromagnetic torque is 11844Nm. After short-circuit demagnetization, the average electromagnetic torque is 10659Nm when the current is 9966A, and the torque loss is about 10%.

[0063] S2: Figure 2 The dotted line in the diagram represents the electromagnetic power curve of the generator before short-circuit demagnetization. The solid line represents the power value represented by 90% of the rated electromagnetic power. The intersection of the two lines is the critical wind speed, which is 13.7 m / s. Therefore, the first wind speed range is [3 m / s, 13.7 m / s). Within this range, to maximize output power, the input power corresponding to each wind speed remains consistent with that before short-circuit demagnetization, while the stator current is fully compensated. The second wind speed range is [13.7 m / s, 20 m / s]. To ensure that the generator winding temperature does not exceed the insulation limit, the current is partially compensated, not exceeding the rated current of 9966 A before short-circuit demagnetization, while the generator output power is correspondingly reduced to ensure power flow balance.

[0064] S3: Calculate the output power after short-circuit demagnetization in the first wind speed range [3m / s, 13.7m / s), taking the case of 9m / s as an example. At a wind speed of 9m / s, the input power before short-circuit demagnetization is 3923kW, the electromagnetic power is 3874kW, the current amplitude is 3274A, and the phase angle is -181.8°. Based on the finite element model of the generator after short-circuit demagnetization, setting the current amplitude to 3637kA and the current phase angle to -181.1°, the calculated electromagnetic power of the generator under this current is 3875kW, and the rotor-side loss is 25kW, totaling 3900kW, which is 99.42% of the input power, not meeting the condition. Further changing the input current amplitude to 3658A and the phase angle to 181.3°, the electromagnetic power is now 3877kW, and the rotor-side loss is 28kW, totaling 3905kW, which is 99.54% of the input power, meeting the condition. The stator-side loss is calculated to be 68kW, and the output power is 3809kW. Using the same method, the output power for other wind speeds within the first wind speed range can be calculated, and the output power curve can be obtained, as shown below. Figure 3 As shown.

[0065] S4: Calculate the output power after short-circuit demagnetization in the second wind speed range [13.7 m / s, 20 m / s], taking the case of a wind speed of 13.9 m / s as an example. At a wind speed of 13.9 m / s, the input power before short-circuit demagnetization is 11030 kW, the electromagnetic power is 11000 kW, the current amplitude is 9804 A, and the phase angle is -196.4°. Based on the finite element model of the generator after short-circuit demagnetization, the input current amplitude is adjusted to 9966 A, and the current phase angle is adjusted to -196.5°. The calculated electromagnetic power of the generator under this current is 10112 kW, the stator-side loss is 388 kW, and the output power is 9724 kW. Simultaneously, the generator rotor-side loss of 30 kW is calculated, and the input power is adjusted to 10142 kW. Following the same method, the output power and input power corresponding to other wind speeds in the second wind speed range can be calculated, and further, the output power curve and input power curve can be obtained, such as... Figure 3 As shown.

[0066] S5: By merging the input and output curves obtained from S3 and S4, the input and output power curves for the entire wind speed range can be obtained, such as... Figure 3 As shown.

[0067] S6: Control of the permanent magnet wind turbine is achieved based on the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0068] Example 2

[0069] This embodiment provides a system for calculating the output and input power of a permanent magnet wind turbine after demagnetization, including:

[0070] Acquisition module: used to acquire the first average electromagnetic torque of the undemagnetized permanent magnet wind turbine under rated current, and to acquire the second average electromagnetic torque of the permanent magnet wind turbine under rated current after short-circuit demagnetization, and to calculate the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque.

[0071] Division module: used to divide the wind speed range of the generator operation after short-circuit demagnetization into a first wind speed range and a second wind speed range based on the torque loss;

[0072] Calculation module: used to calculate the generator's output power in the first wind speed range after short-circuit demagnetization based on the torque loss, while keeping the input power unchanged; and to calculate the generator's input power and output power in the second wind speed range after short-circuit demagnetization based on the torque loss.

[0073] The splicing module is used to splice the input power of the generator in the first and second wind speed ranges after short-circuit demagnetization, and to splice the output power of the generator in the first and second wind speed ranges after short-circuit demagnetization, so as to obtain the input and output power curves of the generator in the full wind speed range after short-circuit demagnetization.

[0074] Control module: Used to control the permanent magnet wind turbine generator based on the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

[0075] Example 3

[0076] This embodiment provides an electronic 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 method for calculating the output and input power of a permanent magnet wind turbine after demagnetization as described in Embodiment 1.

[0077] Example 4

[0078] This embodiment provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it implements the steps of the method for calculating the output and input power of a permanent magnet wind turbine after demagnetization as described in Embodiment 1.

[0079] 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 implemented 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. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for calculating output and input power of a permanent magnet wind power generator after demagnetization, characterized in that, include: Step S1: Obtain the first average electromagnetic torque of the undemagnetized permanent magnet wind turbine under rated current, and obtain the second average electromagnetic torque of the permanent magnet wind turbine under rated current after short-circuit demagnetization. Calculate the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque. Step S2: Based on the torque loss, the wind speed range of the generator operation after short-circuit demagnetization is divided into a first wind speed range and a second wind speed range. Step S3: Calculate the generator output power in the first wind speed range after short-circuit demagnetization based on the torque loss, while keeping the input power unchanged; calculate the generator input power and output power in the second wind speed range after short-circuit demagnetization based on the torque loss. The method for calculating the generator output power in the first wind speed range after short-circuit demagnetization based on the torque loss in step S3 includes: First wind speed range Set the generator input current amplitude to The current phase angle is The electromagnetic power of the generator under this current was calculated based on the finite element model of the generator. Rotor-side losses ,in, For torque loss, For wind speed v i The corresponding current amplitude at that time It is an inverse cosine function. For grid connection voltage, For wind speed v i The corresponding back electromotive force, Phase resistance; like If the preset conditions are met, the stator-side losses are calculated based on the generator finite element model. The final generator output power is ; like If the preset conditions are not met, the generator input current amplitude will be changed to... The current phase angle is ,until If the preset conditions are met, the stator-side losses are calculated based on the generator finite element model. The final generator output power is ,in, For wind speed v i The corresponding input power at that time, In the j-th iteration, when the wind speed is v i The corresponding electromagnetic power at that time In the j-th iteration, when the wind speed is v i The corresponding rotor-side loss, And it is an integer; Step S4: Combine the input power of the generator after short-circuit demagnetization in the first and second wind speed ranges, and combine the output power of the generator after short-circuit demagnetization in the first and second wind speed ranges to obtain the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization. Step S5: Control the permanent magnet wind turbine generator based on the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

2. The method for calculating the output and input power of a permanent magnet wind turbine after demagnetization according to claim 1, characterized in that: Step S1 calculates the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque, expressed as follows: ； in, For torque loss, The first average electromagnetic torque, This is the second average electromagnetic torque.

3. The method for calculating the output and input power of a permanent magnet wind turbine after demagnetization according to claim 1, characterized in that: The method for dividing the wind speed range of the generator operation after short-circuit demagnetization into a first wind speed range and a second wind speed range based on the torque loss in step S2 includes: Based on the aforementioned torque loss, the wind speed range during generator operation after short-circuit demagnetization is divided into a first wind speed range. Second wind speed range ,in, To cut into wind speed, Critical wind speed and , For torque loss, This is the rated output power of the generator before demagnetization. To cut off the wind speed.

4. The method for calculating the output and input power of a permanent magnet wind turbine after demagnetization according to claim 3, characterized in that: In the first wind speed range To maximize the generator's output power, the input power corresponding to each wind speed is... The current remains consistent with that before short-circuit demagnetization, and the generator stator current is fully compensated. The full compensation means that the current amplitude of the stator current is compensated without restriction until the electromagnetic power after compensation plus the various losses of the generator equals the input power. In the second wind speed range To ensure that the generator winding temperature does not exceed the insulation limit, limited compensation is applied to the generator stator current. This limited compensation involves compensating for the stator current amplitude, and the compensated stator current does not exceed the rated current before short-circuit demagnetization. At the same time, the generator input power is adjusted to ensure power flow balance.

5. The method for calculating the output and input power of a permanent magnet wind turbine after demagnetization according to claim 1, characterized in that: The Meeting the preset conditions is represented as: .

6. The method for calculating the output and input power of a permanent magnet wind turbine after demagnetization according to claim 1, characterized in that: The method for calculating the input and output power of the generator in the second wind speed range after short-circuit demagnetization based on the torque loss in step S3 includes: Second wind speed range Based on the finite element model of the generator after short-circuit demagnetization, the amplitude of the generator input current is set to be... The current phase angle is adjusted to The electromagnetic power of the generator under this current was calculated based on the finite element model of the generator. Stator-side losses The final generator output power is ,in, For torque loss, It is an inverse cosine function. For grid connection voltage, For wind speed v i The corresponding back electromotive force, For phase resistance, Rated current; Simultaneously, the rotor-side loss of the generator is calculated based on the finite element model of the generator. Adjust the generator input power to ,in, For wind speed v i The corresponding input power at that time.

7. A system for calculating the output and input power of a permanent magnet wind turbine after demagnetization, used to implement the method for calculating the output and input power of a permanent magnet wind turbine after demagnetization as described in any one of claims 1 to 6, characterized in that, include: Acquisition module: used to acquire the first average electromagnetic torque of the undemagnetized permanent magnet wind turbine under rated current, and to acquire the second average electromagnetic torque of the permanent magnet wind turbine under rated current after short-circuit demagnetization, and to calculate the torque loss caused by short-circuit demagnetization based on the first average electromagnetic torque and the second average electromagnetic torque. Division module: used to divide the wind speed range of the generator operation after short-circuit demagnetization into a first wind speed range and a second wind speed range based on the torque loss; Calculation module: used to calculate the generator's output power in the first wind speed range after short-circuit demagnetization based on the torque loss, while keeping the input power unchanged; and to calculate the generator's input power and output power in the second wind speed range after short-circuit demagnetization based on the torque loss. The splicing module is used to splice the input power of the generator in the first and second wind speed ranges after short-circuit demagnetization, and to splice the output power of the generator in the first and second wind speed ranges after short-circuit demagnetization, so as to obtain the input and output power curves of the generator in the full wind speed range after short-circuit demagnetization. Control module: Used to control the permanent magnet wind turbine generator based on the input and output power curves of the generator across the entire wind speed range after short-circuit demagnetization.

8. An electronic 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 method for calculating the output and input power of a permanent magnet wind turbine after demagnetization as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the method for calculating the output and input power of a permanent magnet wind turbine after demagnetization as described in any one of claims 1 to 6.

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