Wind power generation system and method based on doubly-fed motor intelligent switching

Abstract

The invention provides a wind power generation system and method based on doubly-fed motor intelligent switching, and belongs to the technical field of wind power generation. The system comprises a doubly-fed asynchronous generator, a full-power frequency converter, an intelligent mode control module, a reconfigurable main circuit and a data acquisition module, a stator winding of the doubly-fed asynchronous generator is connected with a power grid through the reconfigurable main circuit, and a rotor winding is connected with a rotor side frequency converter. The full-power frequency converter is connected with a rotor-side frequency converter of the doubly-fed asynchronous generator in parallel, and the intelligent mode control module is configured to judge whether mode conversion needs to be carried out on the doubly-fed asynchronous generator or not according to the wind speed information collected by the data collection module and a preset mode conversion model, and control the intelligent mode control module when mode conversion needs to be carried out. And generating a switching instruction for controlling mode switching. By monitoring the wind speed information and according to the mode conversion model, the operation mode of the doubly-fed asynchronous generator can be intelligently switched, so that the power generation efficiency of the power generation system in a low wind speed section is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and particularly to a wind power generation system and method based on intelligent switching of a doubly-fed motor. Background Art

[0002] In the context of the continuous growth of the global demand for clean energy, wind power generation, as a sustainable and pollution-free way of obtaining energy, has been widely applied and developed. In traditional wind power generation systems, doubly-fed generators have become relatively common power generation equipment due to their relatively high power generation efficiency and good speed regulation performance under certain operating conditions.

[0003] However, a series of problems have emerged in the actual operation of traditional doubly-fed generators. The working characteristics of their stator windings and rotor windings have obvious limitations when facing complex and variable wind speed environments. For example, in low wind speed regions, the doubly-fed induction generator only relies on the stator winding to output electrical energy, resulting in low power generation efficiency and difficulty in fully utilizing wind energy resources. At the same time, there is a lack of an effective power buffering mechanism in traditional systems, and large power fluctuations are likely to occur during the moment of operation mode switching, causing impacts on equipment and shortening the service life of the equipment. Summary of the Invention

[0004] The present invention provides a wind power generation system and method based on intelligent switching of a doubly-fed motor to solve the problems of low power generation efficiency and poor stability existing in the prior art.

[0005] To achieve the above object, an embodiment of the present invention provides a wind power generation system based on intelligent switching of a doubly-fed motor. The wind power generation system includes a doubly-fed induction generator, a full-power frequency converter, an intelligent mode control module, a reconfigurable main circuit, and a data acquisition module. Among them, the stator winding of the doubly-fed induction generator is connected to the power grid through the reconfigurable main circuit, the rotor winding is connected to the rotor-side frequency converter, the full-power frequency converter is connected in parallel with the rotor-side frequency converter of the doubly-fed induction generator, and the intelligent mode control module is configured to determine whether it is necessary to perform a mode conversion on the doubly-fed induction generator according to the wind speed information collected by the data acquisition module and a preset mode conversion model, and generate a switching instruction for controlling the mode switching when a mode conversion is required.

[0006] Optionally, the reconfigurable main circuit is used to switch the grid connection mode of the stator winding. The reconfigurable main circuit includes a stator grid-connected contactor, a stator short-circuit contactor, and an IGBT switch matrix. Among them, the stator grid-connected contactor and the stator short-circuit contactor are isolated through a hardware interlock circuit.

[0007] Optionally, the wind power generation system further includes: a power buffer device connected to the DC bus of the full-power frequency converter for absorbing transient power fluctuations during mode switching.

[0008] Optionally, the mode conversion model is constructed based on the LSTM algorithm and is built-in with a Q-learning switching decision maker. The mode conversion model is used to predict the future wind speed through the LSTM algorithm, and the Q-learning switching decision maker generates a switching decision algorithm according to the predicted wind speed and the long-term revenue learning results of the doubly-fed induction generator in different operating modes.

[0009] Optionally, the intelligent mode control module includes: a multi-core DSP processor for executing the switching decision algorithm to generate the switching instruction; a phase-locked loop unit connected to the output end of the doubly-fed induction generator for real-time tracking of the phase information output by the doubly-fed induction generator to achieve pre-synchronization control.

[0010] Optionally, the wind power generation system further includes: a power buffer unit connected to the DC bus of the full-power frequency converter for absorbing transient power fluctuations during mode switching. The power buffer unit is a supercapacitor array, and its capacitance C satisfies the following formula:

[0011] where represents the rated power of the wind turbine generator set, represents the time required for buffering during the mode switching process, represents the highest operating voltage of the supercapacitor array, represents the lowest operating voltage of the supercapacitor array, represents the discharge efficiency of the supercapacitor array.

[0012] On the other hand, a wind power generation method is provided, which is applied to the above wind power generation system, and includes: obtaining wind speed information; judging whether it is necessary to perform mode conversion on the doubly-fed induction generator according to the obtained wind speed information; when mode conversion is required, generating and executing a mode switching instruction, and switching the operating mode of the doubly-fed induction generator according to the generated switching instruction.

[0013] Optionally, determining whether to perform mode conversion on the doubly-fed induction generator according to the acquired wind speed information includes: predicting the wind speed within a preset future time period according to the acquired wind speed information; outputting Q values in different modes according to the predicted wind speed; when the predicted wind speed is lower than a preset threshold and the Q value in the full-power mode is greater than the Q value in the doubly-fed mode, the doubly-fed induction generator needs to be switched to the full-power mode, and a corresponding switching decision algorithm is generated; when the predicted wind speed is higher than the preset threshold, or the Q value in the full-power mode is less than the Q value in the doubly-fed mode, the doubly-fed induction generator needs to be switched to the doubly-fed mode, and a corresponding switching decision algorithm is generated.

[0014] Optionally, when mode conversion is required, generating and executing a mode switching instruction, and switching the operating mode of the doubly-fed induction generator according to the generated switching instruction includes: when mode conversion is required, generating a switching instruction according to the generated switching decision algorithm; switching the operating mode of the doubly-fed induction generator according to the generated switching instruction.

[0015] Optionally, switching the operating mode of the doubly-fed induction generator according to the generated switching instruction includes: adjusting the output phase of the doubly-fed induction generator through a phase-locked loop unit to make it consistent with the grid limit; controlling the reconfigurable main circuit according to the switching instruction, switching the states of the stator grid-connected contactor and the stator short-circuit contactor, and controlling the start and stop of the full-power frequency converter, and adjusting the power output of the rotor-side frequency converter within a preset time to switch the operating mode of the doubly-fed induction generator.

[0016] A wind power generation system and method based on intelligent switching of a doubly-fed motor provided by the present invention make precise decisions based on real-time wind speed through an intelligent mode control module. When the wind speed is in the normal range, the system operates in the doubly-fed mode and generates electricity using the high-efficiency characteristics of the doubly-fed induction generator under this working condition; when the wind speed is lower than a specific threshold, it automatically switches to the full-power mode. The full-power frequency converter can stably process the generated power within a wider wind speed range, effectively avoiding the situation where the output power of the generator drops significantly due to too low wind speed, significantly improving the power generation efficiency during low-wind-speed periods, and making the entire power generation process more efficient and stable. By intelligently switching between the doubly-fed mode and the full-power mode, the respective advantages of the doubly-fed induction generator and the full-power frequency converter are fully utilized. Under suitable wind speed and grid conditions, the work tasks of the equipment are reasonably allocated, avoiding overuse or idleness of the equipment, realizing the optimal allocation of internal resources of the power generation system, and further improving the operating efficiency and economy of the entire system. Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In the drawings: Figure 1 is a flowchart of the wind power generation system provided by an embodiment of the present invention; Figure 2 is a circuit topology diagram of a doubly-fed unit provided by an embodiment of the present invention; Figure 3 is a schematic diagram showing the relationship between the output voltage capacity of the frequency converter and the rotational speed provided by an embodiment of the present invention; Figure 4 is the relationship between the wind capture efficiency of the wind turbine and the tip speed ratio provided by an embodiment of the present invention; Figure 5 is an electrical topology diagram of a full-power frequency converter provided by an embodiment of the present invention; Figure 6 is a schematic diagram showing the energy flow of two operating modes of full-power and doubly-fed provided by an embodiment of the present invention; Figure 7 is a flowchart of the wind power generation method provided by an embodiment of the present invention; Figure 8 is a test evaluation form of the wind power generation system provided by an embodiment of the present invention. Detailed Embodiments

[0018] The following will detail the specific embodiments of the embodiments of the present invention in conjunction with the drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0019] It should be noted that the acquisition, transmission, storage, use, processing, etc. of data in the technical solution of this application all comply with the relevant regulations of national laws and regulations. In the embodiments of this application, certain industry-existing solutions such as software, components, models, etc. may be mentioned. They should be regarded as exemplary, and their purpose is only to illustrate the feasibility in the implementation of the technical solution of this application, but it does not mean that the applicant has already or necessarily used this solution.

[0020] In the context of the global active promotion of the clean energy transformation, wind power generation, as a sustainable and pollution-free way of obtaining energy, occupies an increasingly important position in the energy structure. In recent years, the installed capacity of wind power generation has continued to grow rapidly, making significant contributions to alleviating the energy crisis and reducing carbon emissions. Traditional wind power generation systems mostly adopt a single operating mode. For example, the widely used doubly-fed induction generator system. However, when the wind speed is lower than a specific threshold, due to the limited regulation ability of the rotor-side converter, the output power of the generator drops significantly, and the power generation efficiency decreases sharply. Therefore, it is urgent to develop a wind power generation technology that can flexibly adapt to different wind speeds and grid conditions and effectively reduce costs.

[0021] To address this problem, the present invention provides a wind power generation system and method based on intelligent switching of doubly-fed motors. This system can flexibly switch the operating mode of the doubly-fed motor according to the wind speed, enabling it to maintain high-efficiency power generation at different wind speeds and improving the power generation efficiency; in the face of grid anomalies, it can quickly switch the mode of the doubly-fed motor to enhance grid adaptability; the phase-locked loop unit ensures that the generator output is synchronized with the grid phase, reducing power fluctuations and equipment losses; the power buffer device absorbs the transient power fluctuations during mode switching to protect the safety of the equipment. The present invention provides a comprehensive, safe, and efficient solution for optimizing wind power generation technology, comprehensively enhancing the performance and economy of the wind power generation system.

[0022] The following will Figures 1 - 8 describe the present invention in detail.

[0023] As Figure 1 shown, an embodiment of the present invention provides a wind power generation system based on intelligent switching of doubly-fed motors. The wind power generation system includes a doubly-fed induction generator, a full-power converter, an intelligent mode control module, a reconfigurable main circuit, and a data acquisition module. Among them, the stator winding of the doubly-fed induction generator is connected to the grid through the reconfigurable main circuit, the rotor winding is connected to the rotor-side converter, the full-power converter is connected in parallel with the rotor-side converter of the doubly-fed induction generator, and the intelligent mode control module is configured to judge whether it is necessary to perform mode conversion on the doubly-fed induction generator according to the wind speed information collected by the data acquisition module and the preset mode conversion model, and generate a switching instruction for controlling mode switching when mode conversion is required.

[0024] As Figure 2 shown, in the currently common intelligent doubly-fed units, when the fan is connected to the grid and operates, most of the power directly feeds from the generator stator through the stator contactor to the grid, and a small part of the power feeds from the generator rotor through the doubly-fed converter to the grid. Under this topological structure, the loss of the fan in the converter part is relatively low.

[0025] As Figure 3As shown in the figure, during the operation of a traditional doubly-fed wind turbine, when the rotational speed of the wind turbine deviates from the synchronous speed, the output voltage of the rotor of the frequency converter will increase. Due to the limited output voltage capacity of the frequency converter, the doubly-fed wind turbine has certain requirements for the operating speed range.

[0026] In addition, at a specific pitch angle, when the tip speed ratio reaches a certain value, the wind capture efficiency of the wind turbine is optimal. Specifically, as shown in Figure 4 the figure. The tip speed ratio is the ratio of the linear speed of the tip of the wind turbine blade to the wind speed. In the low wind speed section, the wind turbine has better capture efficiency when the rotational speed is low. However, due to the operating speed requirements of the doubly-fed unit, the tip speed ratio deviates from the optimal part of the efficiency, resulting in a low energy conversion rate.

[0027] As shown in Figure 5 the figure, the rotor end of the full-power unit is connected to the power grid through a full-power frequency converter. In this mode, all power is fed to the power grid after being rectified and inverted by the frequency converter. The advantage of this mode is that it has relatively low requirements for the operating speed of the generator and also has relatively low requirements for the cut-in wind speed. However, the disadvantage is that there will be a certain power loss after the power passes through the frequency converter. When the wind speed is high, there will be obvious losses compared with the doubly-fed unit.

[0028] A wind power generation system based on intelligent switching of a doubly-fed motor provided by an embodiment of the present invention can collect wind speed information through a data acquisition module and transmit the collected wind speed information to an intelligent mode control module. A preset mode conversion model in the intelligent mode control module will judge whether it is necessary to perform mode conversion on the doubly-fed asynchronous generator according to the collected wind speed information. When mode conversion is required, the intelligent mode control module will control the operating states of the reconfigurable main circuit and the full-power frequency converter, thereby realizing the switching of the power generation mode of the doubly-fed asynchronous generator, realizing the switching of the operating mode of the wind turbine according to the wind speed, increasing the capture efficiency of the wind power system in a wider wind speed range, and thus improving the power generation efficiency. And under appropriate wind speed and grid conditions, the equipment work tasks are reasonably allocated, avoiding overuse or idleness of the equipment, realizing the optimal allocation of internal resources of the power generation system, and further improving the operating efficiency and economy of the entire system.

[0029] Preferably, the reconfigurable main circuit is used to switch the grid connection mode of the stator winding. The reconfigurable main circuit includes a stator grid-connected contactor, a stator short-circuit contactor, and an IGBT switch matrix. Among them, the stator grid-connected contactor and the stator short-circuit contactor are isolated through a hardware interlock circuit.

[0030] In a preferred embodiment of the present invention, the core function of the reconfigurable main circuit is to switch the grid connection mode of the stator winding to adapt to the operating requirements of the doubly-fed induction generator in different modes. The stator grid-connected contactor is responsible for connecting the stator winding to the grid in the doubly-fed mode to achieve normal power generation and grid connection; while the stator short-circuit contactor shorts the stator winding when switching to the full-power mode to cooperate with the full-power frequency converter. In addition, the stator grid-connected contactor and the stator short-circuit contactor are isolated by a hardware interlock circuit, which eliminates the possibility of both of them conducting simultaneously at the hardware level. If both of them conduct simultaneously, serious faults such as short circuits will occur, damaging the equipment and even endangering the safety of the entire power generation system. Through the hardware interlock circuit, the accuracy and stability of the circuit connection state are ensured during the mode switching process, guaranteeing the reliable operation of the system.

[0031] Preferably, the wind power generation system further includes a power buffer device connected to the DC bus of the full-power frequency converter for absorbing the transient power fluctuations during mode switching.

[0032] In a preferred embodiment of the present invention, the power buffer device can ensure the stability of the DC bus voltage of the full-power frequency converter. When the doubly-fed induction generator switches modes, transient power fluctuations will occur. For example, when switching from the doubly-fed mode to the full-power mode instantaneously, the power transmission path and the operating state of the equipment change, resulting in rapid changes in power. If not handled, these fluctuations will damage the full-power frequency converter and the entire power generation system, affecting power generation stability and equipment life. The power buffer device is connected to the DC bus of the full-power frequency converter and can absorb these transient power fluctuations in a timely manner, ensuring the stability of the DC bus voltage of the full-power frequency converter, thereby guaranteeing the normal operation of the full-power frequency converter and enabling the entire wind power generation system to smoothly transition during the mode switching process, improving the reliability and stability of the system.

[0033] Preferably, the mode conversion model is constructed based on the LSTM algorithm and is built-in with a Q-learning switching decision maker. The mode conversion model is used to predict the future wind speed through the LSTM algorithm, and the Q-learning switching decision maker generates a switching decision algorithm according to the predicted wind speed and the long-term revenue learning results of the doubly-fed induction generator in different operating modes.

[0034] In a preferred embodiment of the present invention, the long short-term memory network (LSTM) is a special type of recurrent neural network that can effectively process time series data and capture long-term dependencies in the data. In a wind power generation system, historical wind speed data exhibits obvious time series characteristics. A pattern conversion model constructed based on the LSTM algorithm can learn from this historical data to predict the wind speed change trend over a period of time in the future. At the same time, the Q-learning switching decision maker will continuously update the Q values corresponding to different states / actions according to the wind speed predicted by the LSTM algorithm, in combination with the long-term reward learning results of the doubly-fed induction generator in different operating modes. When a mode switch is required, the Q-learning switching decision maker will select the action with the maximum Q value to generate an optimal switching decision algorithm.

[0035] Preferably, the intelligent mode control module includes: a multi-core DSP processor for executing the switching decision algorithm and generating a switching instruction; a phase-locked loop unit connected to the output terminal of the doubly-fed induction generator for continuously tracking the phase information of the output of the doubly-fed induction generator to achieve pre-synchronization control.

[0036] In a preferred embodiment of the present invention, the multi-core DSP processor will calculate and analyze the switching decision algorithm to generate corresponding switching instructions. The phase-locked loop unit continuously monitors the phase of the generator output voltage and compares it with the phase of the power grid. When a deviation is found, it will generate a corresponding control signal to adjust the operating state of the generator, so that the phase of the generator output gradually approaches the power grid phase to achieve pre-synchronization control.

[0037] Illustrated by an example, for example, when the switching decision algorithm determines that a switch from the doubly-fed mode to the full-power mode is required, the multi-core DSP processor will generate a series of precise control instructions for controlling operations such as the action of the contactor in the reconfigurable main circuit, the startup of the full-power frequency converter, and the power adjustment of the rotor-side frequency converter, to ensure the smooth progress of the mode switching process.

[0038] Illustrated by an example, for example, when switching from the doubly-fed mode to the full-power mode, the phase-locked loop unit can synchronize the output of the doubly-fed induction generator with the power grid phase in advance to ensure that the generator can smoothly integrate electrical energy into the power grid after switching, reducing power fluctuations and interference to the power grid during the switching process.

[0039] Preferably, the wind power generation system further includes: a power buffer unit connected to the DC bus of the full-power frequency converter for absorbing transient power fluctuations during mode switching. The power buffer unit is a supercapacitor array, and its capacitance C satisfies the following formula: (1) Wherein, represents the rated power of the wind turbine generator set, It is expressed as the time to be buffered during the mode switching process. It is expressed as the maximum operating voltage of the supercapacitor array. It is expressed as the minimum operating voltage of the supercapacitor array. It is expressed as the discharge efficiency of the supercapacitor array.

[0040] During mode switching, since the doubly-fed induction generator changes from one operating mode to another, the power transmission and distribution of the entire system will change significantly, resulting in transient power fluctuations. If these fluctuations are not handled, they may damage equipment such as the full-power frequency converter, affecting the normal operation and stability of the system. The supercapacitor array is connected to the DC bus of the full-power frequency converter and can quickly absorb and release electrical energy. When there is a sudden increase in power during mode switching, the supercapacitor can quickly store the excess electrical energy to prevent the DC bus voltage from being too high; when the power suddenly decreases, the supercapacitor can release the stored electrical energy in time to maintain the stability of the DC bus voltage. And through Equation (1), the capacity of the supercapacitor array can be reasonably determined according to the specific parameters of the wind power generation system (rated power, switching time, etc.) to ensure that it can effectively absorb the transient power fluctuations during mode switching and guarantee the stable operation of the full-power frequency converter and the entire wind power generation system.

[0041] To sum up, the full-power - doubly-fed intelligent switching technology, through local hardware transformation and control algorithm optimization, enables the generator to change from the doubly-fed mode to the full-power mode under low wind speed conditions. In this mode, the open-circuit voltage of the rotor is proportional to the speed, thus breaking through the lower limit of the operating speed of the traditional doubly-fed wind turbine and achieving the best energy capture efficiency of the wind turbine throughout the wind speed range. In addition, in the full-power mode, the generator is not directly connected to the power grid, and the electrical drive chain power generation efficiency can be greatly improved through the optimized motor excitation control method. Therefore, different drive chain topology forms are adopted under low wind speed conditions and high wind speed conditions, combined with an intelligent mode conversion model, and according to the wind condition characteristics, the mode is calculated and switched in real time to achieve the optimal capture of wind energy.

[0042] As Figure 6 shown, as Figure 6 shows the energy flow of the doubly-fed induction generator in two operating modes. At low wind speeds and in the low-power section, all energy is transmitted to the power grid through the frequency converter, and the frequency converter operates as a full-power frequency converter. At high wind speeds and in the high-power section, the frequency converter still operates as a partial-capacity frequency converter.

[0043] As Figure 7As shown in the figure, the embodiment of the present invention further provides a wind power generation method, which is applied to the above wind power generation system. The wind power generation method includes: obtaining wind speed information; judging whether it is necessary to perform mode conversion on the doubly-fed induction generator according to the obtained wind speed information; when mode conversion is required, generating and executing a mode switching instruction, and switching the operating mode of the doubly-fed induction generator according to the generated switching instruction.

[0044] The wind power generation method provided by the present invention can judge whether the doubly-fed induction generator needs to perform mode conversion according to the wind speed information, and quickly switch the operating mode of the doubly-fed induction generator when mode conversion is required.

[0045] In step 102, judging whether it is necessary to perform mode conversion on the doubly-fed induction generator according to the obtained wind speed information includes: predicting the wind speed in a preset future time period according to the obtained wind speed information; outputting Q values in different modes according to the predicted wind speed; when the predicted wind speed is lower than the preset threshold and the Q value in the full power mode is greater than the Q value in the doubly-fed mode, it is necessary to switch the doubly-fed induction generator to the full power mode and generate a corresponding switching decision algorithm; when the predicted wind speed is higher than the preset threshold or the Q value in the full power mode is less than the Q value in the doubly-fed mode, it is necessary to switch the doubly-fed induction generator to the doubly-fed mode and generate a corresponding switching decision algorithm.

[0046] In step 103, when mode conversion is required, generating and executing a mode switching instruction, and switching the operating mode of the doubly-fed induction generator according to the generated switching instruction includes: when mode conversion is required, generating a switching instruction according to the generated switching decision algorithm; switching the operating mode of the doubly-fed induction generator according to the generated switching instruction.

[0047] In the wind power generation method provided by the embodiments of the present invention, when determining whether mode conversion is required, the wind power generation system will use the mode conversion model constructed based on the LSTM algorithm to predict the wind speed within a preset future period according to the acquired real-time wind speed information. Subsequently, according to the predicted wind speed, the Q-learning switching decision maker built into the mode conversion model outputs the Q values corresponding to the doubly-fed mode and the full-power mode under this wind speed condition. The Q value represents the predicted value of the long-term cumulative reward that can be obtained by selecting the doubly-fed mode or the full-power mode at the predicted wind speed. When the predicted wind speed is lower than the preset threshold and the Q value of the full-power mode is greater than the Q value of the doubly-fed mode, it indicates that switching to the full-power mode can obtain better long-term benefits in this low-wind-speed situation. Therefore, the system determines that the doubly-fed asynchronous generator needs to be switched to the full-power mode and generates the corresponding switching decision algorithm. Conversely, when the predicted wind speed is higher than the preset threshold, or the Q value of the full-power mode is less than the Q value of the doubly-fed mode, the doubly-fed mode is more advantageous, and the system decides to switch the generator back to the doubly-fed mode and generates the corresponding switching decision algorithm. When the doubly-fed asynchronous generator needs to perform mode conversion, the multi-core DSP processor further generates specific mode switching instructions according to the generated switching decision algorithm. These instructions precisely specify the actions and operation sequences of each device (such as the reconfigurable main circuit, full-power frequency converter, rotor-side frequency converter, etc.). By controlling these devices, the operation mode of the doubly-fed asynchronous generator is switched.

[0048] Taking an example, for instance, the preset threshold is 6 m / s, the current wind speed is 4 m / s, the Q value of the full-power mode is 80, and the Q value of the doubly-fed mode is 40. Then, at this time, the current wind speed is less than the preset threshold, and the Q value of the full-power mode is greater than the Q value of the doubly-fed mode. It is determined that the doubly-fed asynchronous generator at this time needs to be converted to the full-power mode.

[0049] Preferably, according to the generated switching instructions, switching the operation mode of the doubly-fed asynchronous generator includes: adjusting the output phase of the doubly-fed asynchronous generator through the phase-locked loop unit to make it consistent with the grid limit; controlling the reconfigurable main circuit according to the switching instructions, switching the states of the stator grid-connected contactor and the stator short-circuit contactor, and controlling the start and stop of the full-power frequency converter, and adjusting the power output of the rotor-side frequency converter within a preset time to switch the operation mode of the doubly-fed asynchronous generator.

[0050] For example, when a doubly-fed induction generator needs to switch from the doubly-fed mode to the full-power mode, first, the phase-locked loop unit continuously fine-tunes the operating parameters of the generator to precisely match the output phase with the grid phase. Subsequently, according to the switching instruction, the reconfigurable main circuit disconnects the stator grid-connected contactor, cuts off the conventional connection between the stator winding and the grid, and closes the stator short-circuit contactor to short-circuit the stator winding, preparing the circuit for operation in the full-power mode. Finally, the full-power frequency converter is also started under the control of the switching instruction, gradually taking over all the power processing tasks of the power generation system. The mode switching is completed.

[0051] In a preferred embodiment of the present invention, during the entire mode switching process, each link closely cooperates. Through precise instruction control and equipment coordination, a smooth and efficient switching of the operating mode of the doubly-fed induction generator is achieved, ensuring that the wind power generation system can operate stably and reliably under different working conditions, and improving the power generation efficiency and system adaptability.

[0052] As Figure 8 shown, for the wind power generation system and method provided by the present invention, the average power generation performance under the effective data of all the units in the test stage is improved by 0.94%, meeting the expectations of the preliminary feasibility study. Through the transformation of the full-power - doubly-fed intelligent switching technology, the system efficiency of the generator set in the low-power section is significantly improved. The output power of the unit increases in the full wind speed section, and the cut-in wind speed decreases, expanding the wind speed range of the unit operation and increasing the power generation of the unit. The full-power - doubly-fed intelligent switching transformation technology of the fan can also be applied to the transformation of the existing wind farms, with obvious effects of improving quality and increasing efficiency, and having broad application and transformation prospects.

[0053] In summary, for a wind power generation system and method based on intelligent switching of a doubly-fed motor provided by the present invention, through the intelligent mode control module, according to the wind speed, the operating mode of the doubly-fed induction generator is precisely switched, significantly improving the power generation efficiency and ensuring power generation stability under low wind speeds and abnormal grid conditions; by using the coordinated operation of the reconfigurable main circuit, phase-locked loop unit, power buffer device, etc., the grid adaptability is enhanced, the equipment loss and maintenance cost are reduced, and at the same time, the resource allocation is optimized, reducing the high-cost usage period of the full-power frequency converter, comprehensively improving the system reliability and economy.

[0054] It should be understood that in various embodiments of the present invention, the magnitude of the sequence numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0055] In addition, the terms "system" and "network" in this document are often used interchangeably herein. The term "and / or" in this document is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally represents an "or" relationship between the associated objects before and after.

[0056] It should be understood that in the embodiments of the present invention, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0057] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this document can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0058] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0059] In several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling or direct coupling or communication connection to each other can be an indirect coupling or communication connection through some interfaces, devices, or units, and can also be in an electrical, mechanical, or other form of connection.

[0060] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiments of the present invention.

[0061] In addition, in each embodiment of the present invention, each functional unit may be integrated into a processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of a software functional unit.

[0062] From the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware, or by firmware, or by a combination thereof. When implemented in software, the above functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. The computer-readable medium includes computer storage media and communication media, where the communication media includes any medium that facilitates the transfer of a computer program from one place to another. The storage media can be any available medium that can be accessed by a computer. By way of example but not limitation: the computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer. In addition, any connection may suitably be a computer-readable medium. For example, if the software is transmitted using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technologies such as infrared, radio and microwave from a website, server or other remote source, then the coaxial cable, fiber optic cable, twisted pair, DSL or wireless technologies such as infrared, wireless and microwave are included in the definition of the medium. As used in the present invention, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, where disk generally magnetically replicates data, while disc optically replicates data with a laser. The above combinations should also be included within the scope of protection of the computer-readable medium.

[0063] In summary, the above are only the preferred embodiments of the technical solution of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A wind power generation system based on intelligent switching of a doubly-fed generator, characterized in that: The wind power generation system includes a double-fed asynchronous generator, a full-power inverter, an intelligent mode control module, a reconfigurable main circuit and a data acquisition module. The stator winding of the doubly-fed asynchronous generator is connected to the power grid through the reconfigurable main circuit, the rotor winding is connected to the rotor-side frequency converter, and the full-power frequency converter is connected in parallel with the rotor-side frequency converter of the doubly-fed asynchronous generator. The intelligent mode control module is configured to determine whether it is necessary to perform mode conversion on the double-fed asynchronous generator based on the wind speed information collected by the data acquisition module and a preset mode conversion model, and to generate a switching instruction for controlling mode switching when mode conversion is required.

2. The wind power generation system according to claim 1, characterized in that: The reconfigurable main circuit is used to switch the grid connection mode of the stator winding, and the reconfigurable main circuit includes a stator grid-connected contactor, a stator short-circuit contactor and an IGBT switch matrix. Wherein, the stator grid-connected contactor and the stator short-circuit contactor are isolated through a hardware interlocking circuit.

3. The wind power generation system according to claim 1, characterized in that: The wind power generation system further comprises: a power buffer device connected to the DC bus of the full-power inverter and used for absorbing transient power fluctuations during mode switching.

4. The wind power generation system according to claim 1, characterized in that: The mode transition model is constructed based on the LSTM algorithm and has a built-in Q-learning switching decision maker. The mode transition model is used to predict the future wind speed through the LSTM algorithm. The Q-learning switching decision maker generates a switching decision algorithm according to the predicted wind speed and the long-term benefit learning results of the double-fed asynchronous generator under different operating modes.

5. The wind power generation system according to claim 4, characterized in that: The intelligent mode control module comprises: A multi-core DSP processor, used for executing the switching decision algorithm and generating the switching instruction; A phase-locked loop unit is connected to the output end of the double-fed asynchronous generator and is used to track the phase information output by the double-fed asynchronous generator in real time to achieve pre-synchronization control.

6. The wind power generation system according to claim 1, characterized in that: The wind power generation system further comprises: The power buffer unit is connected to the DC bus of the full-power inverter and is used to absorb transient power fluctuations during mode switching. The power buffer unit is a supercapacitor array, and its capacity C satisfies the following formula: in, Expressed as the rated power of the wind turbine, Indicates the buffer time required during mode switching. It is represented as the maximum operating voltage of the supercapacitor array, It is represented as the minimum operating voltage of the supercapacitor array, It is represented as the discharge efficiency of the supercapacitor array.

7. A wind power generation method, characterized in that: A wind power generation system according to any one of claims 1 to 6, comprising: Get wind speed information; According to the acquired wind speed information, it is determined whether the double-fed asynchronous generator needs to be converted into a mode; When mode conversion is required, a mode switching instruction is generated and executed, and the operation mode of the double-fed asynchronous generator is switched according to the generated switching instruction.

8. The wind power generation method according to claim 7, characterized in that: The step of judging whether it is necessary to perform mode conversion on the double-fed asynchronous generator according to the acquired wind speed information includes: Based on the acquired wind speed information, the wind speed within a preset period in the future is predicted; Outputting Q values ​​in different modes according to the predicted wind speed; When the predicted wind speed is lower than the preset threshold and the Q value of the full power mode is greater than the Q value of the double-fed mode, it is necessary to switch the double-fed asynchronous generator to the full power mode and generate a corresponding switching decision algorithm; When the predicted wind speed is higher than a preset threshold, or the Q value of the full power mode is less than the Q value of the double-fed mode, the double-fed asynchronous generator needs to be switched to the double-fed mode, and a corresponding switching decision algorithm is generated.

9. The wind power generation method according to claim 8, characterized in that: When mode conversion is required, generating and executing a mode switching instruction, and switching the operation mode of the double-fed asynchronous generator according to the generated switching instruction includes: When mode switching is required, a switching instruction is generated according to the generated switching decision algorithm; According to the generated switching instruction, the operation mode of the double-fed asynchronous generator is switched.

10. The wind power generation method according to claim 9, characterized in that: The switching of the operation mode of the double-fed asynchronous generator according to the generated switching instruction comprises: By means of a phase-locked loop unit, the output phase of the double-fed asynchronous generator is adjusted to be consistent with the power grid limit; According to the switching instruction, the reconfigurable main circuit is controlled to switch the states of the stator grid-connected contactor and the stator short-circuit contactor, and Control the start and stop of the full-power inverter, and adjust the power output of the rotor-side inverter within a preset time to switch the operating mode of the double-fed asynchronous generator.

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