Independently started and operated fan system, control method, control equipment and medium

Abstract

The embodiment of the invention relates to the field of fans, and discloses an independently started and operated fan system, a control method, control equipment and a medium. The system comprises a wind driven generator which is connected with the low-voltage side of a transformer through a power transmission line, and the power transmission line is provided with a converter; the energy storage device is connected to a first grid connection point on the power transmission line; the power supply switching device comprises an input end which is respectively connected with the energy storage device and a second grid-connected point on the power transmission line, and an output end which is respectively connected with the auxiliary power system and a pre-charging device of the converter; when the fan system is in an off-grid starting mode, the power supply switching device switches the input end to the energy storage device, the energy storage device supplies power to the auxiliary power system so as to control the wind driven generator to rotate, the energy storage device further charges the converter through the pre-charging device, and the converter excites the wind driven generator and constructs output voltage of the wind driven generator. Therefore, the off-grid independent starting of the fan can be realized under the condition that the power grid is completely de-energized.

Description

TECHNICAL FIELD

[0001] The embodiment of the application relates to the fan field, in particular to a fan system, a control method, a control device and a medium which are independently started and operated. BACKGROUND

[0002] With the continuous rise of the proportion of wind power in the global energy structure, the safe and stable operation of the wind farm is crucial to the reliability of the power grid.

[0003] However, the start of the wind turbine generator requires the auxiliary power system to rotate the fan under power supply conditions to establish voltage. After the power grid loses voltage, the fan auxiliary power system (including yaw, variable pitch, cooling, control cabinet, state monitoring system, etc.) is powered off, which makes it difficult for the fan to achieve independent start in off-grid mode under complete power loss of the power grid. SUMMARY

[0004] The purpose of the embodiment of the application is to provide a fan system, a control method, a control device and a medium which are independently started and operated, so that the fan can achieve independent start in off-grid mode under complete power loss of the power grid.

[0005] To solve the above technical problems, the embodiment of the application provides a fan system which is independently started and operated, comprising:

[0006] The wind turbine generator is connected to the low-voltage side of the transformer through the power transmission line, and the power transmission line is provided with a converter; the energy storage device is connected to the first grid connection point on the power transmission line; the first grid connection point is located between the low-voltage side of the transformer and the converter; the power supply switching device comprises an input end connected to the energy storage device and a second grid connection point on the power transmission line, and an output end connected to the auxiliary power system and the pre-charging device of the converter; the second grid connection point is located between the low-voltage side of the transformer and the converter; wherein, in the off-grid start mode, the power supply switching device switches the input end to the energy storage device, the energy storage device supplies power to the auxiliary power system to control the rotation of the wind turbine generator, and the energy storage device also charges the converter through the pre-charging device, the converter excites the wind turbine generator, and the output voltage of the wind turbine generator is constructed.

[0007] The embodiment of the application also provides a control method of an independently started and operated fan system, the fan system comprising a wind driven generator, an energy storage device and a power supply switching device, the wind driven generator being connected with a low voltage side of a transformer through a power transmission line, and a converter being arranged on the power transmission line; the energy storage device being connected with a first grid connection point on the power transmission line, and the first grid connection point being located between the low voltage side of the transformer and the converter; the power supply switching device comprising an input end connected with the energy storage device and a second grid connection point on the power transmission line respectively, and an output end connected with an auxiliary power system and a pre-charging device of the converter respectively; the second grid connection point being located between the low voltage side of the transformer and the converter; the control method comprising: after detecting that the power grid is off-grid, entering an off-grid starting mode, and controlling the power supply switching device to switch the input end to the energy storage device; the energy storage device supplying power to the auxiliary power system to control the wind driven generator to rotate, and the energy storage device also charging the converter through the pre-charging device, the converter exciting the wind driven generator to build an output voltage of the wind driven generator.

[0008] The embodiment of the application also provides a control device of a fan system, comprising: at least one processor; and a memory connected with the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the control method of the independently started and operated fan system as above.

[0009] The embodiment of the application also provides a computer readable storage medium storing a computer program, and the computer program is executed by a processor to implement the control method of the independently started and operated fan system as above.

[0010] In the embodiment of the application, in the case of power grid failure, the power supply switching device first switches the power supply source from the power grid side without power to the energy storage device. The energy storage device then outputs electric energy through two paths: one path supplies power to the auxiliary power system of the fan to ensure that the fan has basic operation and control capability and can rotate according to the wind condition; the other path charges the direct current bus of the converter through the pre-charging device to enable the converter to have working capability. Once the converter is powered and the fan starts to rotate, the converter can excite the wind driven generator to establish a stable output voltage on the generator side. Through this series of orderly scheduling of internal electric energy, the system successfully uses the energy storage device as an initial power source, starts the key components including the auxiliary power system and the converter, and finally realizes the voltage building of the wind driven generator itself, completes the independent starting process from complete shutdown to power generation capability, and breaks away from the dependence on the external power grid. BRIEF DESCRIPTION OF DRAWINGS

[0011] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0012] Figure 1 This is a structural diagram of a wind turbine system that can be independently started and operated according to an embodiment of the present invention;

[0013] Figure 2 This is a structural diagram of a wind turbine system that can be independently started and operated according to an embodiment of the present invention, including a full-power wind turbine generator;

[0014] Figure 3 This is a structural diagram of a wind turbine system that can be independently started and operated according to an embodiment of the present invention, including a doubly fed wind turbine generator;

[0015] Figure 4 This is a structural diagram of a wind turbine system for low wind speed startup provided according to an embodiment of the present invention;

[0016] Figure 5 This is a structural diagram of a control device provided according to an embodiment of the present invention. Detailed Implementation

[0017] As a crucial component of renewable energy, wind power is playing an increasingly important role in the global energy mix. With the expansion of wind farm installed capacity and the continuous increase in single-unit capacity, wind turbines are playing an increasingly vital role in grid operation, and their safe and stable operation directly impacts grid reliability and power system security. During operation, wind turbines not only rely on the main power generation system to convert wind energy into electricity, but also require the coordinated operation of various auxiliary systems. For example, the yaw system adjusts the nacelle orientation to adapt to wind direction changes, the pitch system adjusts the blade angle to maintain stable power output, the cooling and lubrication system ensures the safe operation of electromechanical components, and the control cabinet and condition monitoring system provide logic control and condition monitoring. The normal power supply to these auxiliary systems is a prerequisite for wind turbine startup, grid connection, and stable operation.

[0018] However, wind turbine startup is not solely driven by wind power. It requires the auxiliary power system to provide power, gradually driving the turbine rotor to operate and establishing a controlled voltage via the converter's DC bus, subsequently building the generator voltage for operation. Under normal grid power conditions, this "grid-first" process can be completed smoothly. However, if the grid loses power, the auxiliary power system immediately shuts down, the DC bus cannot be pre-charged, and the turbine's control and drive systems cannot be energized. This makes it difficult for the wind turbine to start independently in the event of a complete grid outage, i.e., off-grid operation.

[0019] Therefore, in order to enable off-grid startup of wind turbines in the event of a complete power outage, embodiments of the present invention provide a wind turbine system, control method, control equipment, and medium for independent startup and operation.

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of the present invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0021] One embodiment of the present invention relates to a wind turbine system that can be started and operated independently, comprising: a wind turbine generator 104 connected to the low-voltage side of a transformer 101 via a power transmission line, wherein a converter 103 is provided on the power transmission line; an energy storage device 106 connected to a first grid connection point on the power transmission line; the first grid connection point is located between the low-voltage side of the transformer 101 and the converter 103; and a power supply switching device 107, including an input terminal connected to the energy storage device 106 and a second grid connection point on the power transmission line, and an input terminal connected to an auxiliary power system 109 and a transformer 103, respectively. The output terminal of the pre-charging device 108 of the converter 103 is connected; the second grid connection point is located between the low-voltage side of the transformer 101 and the converter 103; wherein, in the off-grid start-up mode of the wind turbine system, the power supply switching device 107 switches the input terminal to the energy storage device 106, the energy storage device 106 supplies power to the auxiliary power system 109 to control the rotation of the wind turbine generator 104, and the energy storage device 106 also charges the converter 103 through the pre-charging device 108, the converter 103 excites the wind turbine generator 104, and constructs the output voltage of the wind turbine generator 104. In this embodiment of the invention, in the event of a power grid failure, the power supply switching device 107 first switches the power source from the powerless grid side to the energy storage device 106. The energy storage device 106 then outputs electrical energy through two paths: one path supplies power to the auxiliary power system 109 of the wind turbine, ensuring that the wind turbine has basic operation and control capabilities and can rotate according to wind conditions; the other path charges the DC bus of the converter 103 through the pre-charging device 108, enabling it to operate. Once the converter 103 is energized and the wind turbine starts rotating, the converter 103 can excite the wind turbine generator 104, thereby establishing a stable output voltage on the generator side. Through this series of orderly scheduling of internal electrical energy, the system successfully utilizes the energy storage device 106 as the initial power source to start up key components, including the auxiliary power system and the converter 103, and ultimately achieves voltage construction of the wind turbine generator 104 itself, completing the independent startup process from complete shutdown to generating capacity, thus eliminating dependence on the external power grid.

[0022] The following describes in detail the implementation details of the wind turbine system for independent start-up and operation according to an embodiment of the present invention. The following content is only for the convenience of understanding the implementation details and is not necessary for implementing this solution.

[0023] like Figure 1 As shown, the wind turbine system includes a wind turbine generator 104, an energy storage device 106, a power supply switching device 107, a converter 103, an auxiliary power system 109, a pre-charging device 108, a third switch 105, and a second switch 102, forming a complete system capable of self-starting and continuous operation independently of the power grid.

[0024] The wind turbine 104 is connected to the low-voltage side of the transformer 101 via a power transmission line, on which a converter 103 is installed. Specifically, the wind turbine 104 is electrically connected to the low-voltage side of the transformer 101 via the converter 103, and the power transmission carrier is the power transmission line. Under normal operating conditions, the wind turbine 104 can exchange power with the power grid through the transformer 101. However, when the power grid is de-energized, the wind turbine itself cannot rely on the preceding voltage provided by the power grid to drive the auxiliary system and the DC bus of the converter 103. Therefore, it needs to rely on the energy storage device 106 to achieve independent startup.

[0025] In an optional embodiment, the transformer has at least two windings, including a high-voltage side and a low-voltage side. The high-voltage side is used to connect to the power grid, and the low-voltage side is used to connect to the wind turbine generator 104. Furthermore, it should be noted that when the transformer has more than two windings, it may also include one or more additional windings (e.g., a second low-voltage side, a third low-voltage side, etc.) to construct a central hub integrating a multi-functional electrical interface. For example, this additional winding may be designed as, but is not limited to: a standardized energy access port for convenient integration of other distributed energy units, such as photovoltaic modules, to form a wind-solar hybrid power generation system, and to be stepped up and connected to the grid via a shared main transformer; and an isolated operation and maintenance service power supply, serving as an independent external power supply interface to provide stable power to on-site service equipment during operation and maintenance. Because this interface is physically isolated from other power circuits, its use will not affect the safe operation of the wind turbine main circuit and the core auxiliary power system.

[0026] Energy storage device 106 is connected to the first grid connection point on the power transmission line; the first grid connection point is located between the low-voltage side of transformer 101 and converter 103. Specifically, energy storage device 106 is designed to support not only off-grid start-up mode but also to switch to operating mode after the wind turbine starts. In off-grid start-up mode, the electrical energy output by energy storage device 106 is directly conducted to auxiliary power system 109 and pre-charging device 108 through power supply switching device 107. In this way, auxiliary power system 109 (including yaw, pitch, cooling, control cabinet, and status monitoring units) can quickly restore power supply in the event of a power failure, ensuring that the wind turbine has the most basic operating conditions. At the same time, pre-charging device 108 charges the DC bus of converter 103, thereby enabling converter 103 to excite wind turbine generator 104, laying the foundation for subsequent power generation by wind turbine generator 104. Furthermore, when the wind turbine completes off-grid startup and enters the operation phase, the energy storage device 106 can serve as a backup power source. It can be flexibly configured to charge or discharge state according to the power status generated by the wind turbine generator 104, thereby achieving dynamic energy balance and avoiding fluctuations in the auxiliary power system 109 caused by unstable wind turbine power supply.

[0027] It should be noted that the energy storage device 106 mentioned in this embodiment of the invention can be configured flexibly and in various ways. On the one hand, it can be a new energy storage device 106 specifically designed for off-grid start-up. In this case, the core parameters of the energy storage device 106, such as rated power, response speed, and minimum state of charge (SOC) maintenance threshold, will be optimized based on meeting the black start requirements of the auxiliary power system 109 starting load and the converter 103 pre-charging. Furthermore, this energy storage device 106 for off-grid start-up can be used in a wind-storage integrated unit. That is, while ensuring its black start capability at all times, its surplus capacity and power margin can be invested in conventional wind-storage integrated applications, such as smoothing power fluctuations or participating in grid ancillary services, thereby maximizing its asset value.

[0028] On the other hand, the structure of the wind-storage integrated unit can also be enhanced by adding a series of structures from the embodiments of the present invention. Specifically, in a wind-storage integrated unit primarily designed for grid-connected operation and providing grid-friendly services, the functionality can be expanded by adding the power supply switching device 107 of the present invention, a dedicated electrical isolation and connection circuit, and integrating a corresponding black-start control strategy into the wind turbine system. This allows the energy storage device 106 in the wind-storage integrated unit to be flexibly applied to off-grid start-up scenarios of wind turbine systems, achieving a single unit for multiple uses. Regardless of the configuration method, the core idea is to achieve functional reuse of the energy storage device, avoiding the investment in building an independent backup power system that is mostly idle for black-start purposes. This saves on wind turbine system development costs and solves the problem of off-grid start-up of wind turbines, achieving two goals at once.

[0029] Furthermore, this application utilizes the energy storage device 106 as the power supply for the auxiliary power system 109 and the pre-charging device 108, providing them with a controllable and stable boost power supply. This controllability is reflected in the fact that the power conversion system (PCS) of the energy storage device 106 can respond instantaneously to control commands, achieving precise adjustment of the amplitude, frequency, and phase of the output voltage, outputting high-quality electrical energy, and providing an ideal power environment for the pre-charging of the subsequent converter 103 and the stable operation of the auxiliary power system 109. In contrast, existing black-start methods typically rely on a second generator to supply power and boost the voltage of the auxiliary power system 109 and the pre-charging device 108. However, due to insufficient generator output stability, complex control logic is required during power supply and voltage boosting to ensure the controllability and stability of the converter 103 and the wind turbine side.

[0030] The power supply switching device 107 includes an input terminal connected to the energy storage device 106 and a second grid connection point on the power transmission line, and an output terminal connected to the auxiliary power system 109 and the pre-charging device 108 of the converter 103, respectively. The second grid connection point is located between the low-voltage side of the transformer 101 and the converter 103. Specifically, the power supply switching device 107 can quickly switch the power supply path when a change in power state is detected, thereby quickly completing the switch from grid power supply to energy storage power supply and avoiding interruption of the auxiliary power system 109. In addition, by utilizing the dual power supply capability of the power supply switching device 107, in the operating mode, a more stable power source can be selected to supply power to the auxiliary power system 109 according to the status of the power transmission line and the energy storage side, which can provide continuous and stable power to the auxiliary power system, thereby effectively avoiding the risk of wind turbine oscillation caused by power fluctuations and improving the reliability of the system.

[0031] In an optional embodiment, the power supply switching device 107 described above may be configured as an automatic transfer switch (ATS).

[0032] In this embodiment of the invention, the wind turbine system constructed with the above structure includes two modes: off-grid start-up mode and operating mode. In off-grid start-up mode, the power supply switching device 107 switches the input to the energy storage device 106. The energy storage device 106 supplies power to the auxiliary power system 109 to control the rotation of the wind turbine generator 104. The energy storage device 106 also charges the converter 103 through the pre-charging device 108. The converter 103 excites the wind turbine generator 104, constructing the output voltage of the wind turbine generator 104.

[0033] Therefore, this mode achieves two objectives by using an energy storage system to pre-energize the auxiliary power system 109 and pre-charge the DC bus of the converter 103: first, energizing the auxiliary power system 109 to rotate the wind turbine; and second, pre-charging the converter 103 to enable its excitation capability. The converter 103 then excites the wind turbine, gradually increasing and stabilizing the converted electrical energy into an output voltage. Only after both objectives are achieved can the wind turbine achieve off-grid startup and meet the requirement of transmitting power to the grid.

[0034] In a specific example, the wind turbine system also includes a second switch 102, which is set on the power transmission line and located between the low-voltage side of the transformer 101 and the converter 103; after the output voltage of the wind turbine generator 104 reaches the preset voltage threshold, the second switch 102 switches from the open state to the closed state, and the wind turbine system switches from the off-grid start-up mode to the running mode.

[0035] It should be noted that the aforementioned preset voltage threshold refers to the output voltage of the wind turbine 104 reaching a preset rated voltage, which is set with reference to the configuration of the wind turbine 104 itself. In some scenarios, the rated voltage setting also needs to be considered in conjunction with the specific scenario. Only after the output voltage of the wind turbine 104 is boosted to the preset threshold under the control of the converter 103 can the wind turbine be connected to the grid.

[0036] In a specific example, the wind turbine system also has an operating mode, and the wind turbine system further includes a third switch 105. The energy storage device 106 is connected to the first grid connection point through the third switch 105. After the wind turbine system enters the operating mode, the third switch 105 switches to the closed state, and the energy storage device 106 is configured to charge or discharge according to the state of the first grid connection point. In the operating mode, the third switch 105 is closed to keep the energy storage connected to the power transmission line, and the energy storage is configured to charge / discharge according to the state of the power transmission line.

[0037] As those skilled in the art will understand, in the above embodiments, in the operating mode, the energy storage transforms from a power source during off-grid startup to an energy storage device within the integrated wind and energy storage unit during operation, serving as a peak-shaving and valley-filling device, and is configured for charging and discharging according to different situations. For example, during off-grid operation when the grid is de-energized and there are no electrical loads in the power structure, all the power output from the wind turbine 104 flows to the energy storage device 106, at which point the energy storage is configured in charging mode. However, when the grid is energized, or when there are electrical loads in the power structure, the power output from the wind turbine 104 flows to the grid or the load. In this case, the energy storage compensates for insufficient or fluctuating power and absorbs excess power, thereby achieving a stable power output.

[0038] In a specific example, if the grid is off-grid and the wind turbine 104 generates surplus power, the energy storage device 106 is configured to a charging state. Specifically, after the wind turbine 104 successfully starts and enters off-grid operation, a new problem arises: how to handle the imbalance between the generated power and the minimal auxiliary power load. Under certain wind conditions, the instantaneous generated power of the wind turbine 104 may significantly exceed the requirements of its auxiliary power load. If there are no other local loads at this time, this excess power, i.e., surplus power, cannot be absorbed locally, leading to system instability and shutdown. To address this, the present invention further configures the energy storage device 106 as a dynamic power balancing unit: when surplus power is detected, the energy storage device 106 is configured to a charging state to absorb the surplus power generated by the off-grid operation of the wind turbine 104. Thus, with only the energy storage structure of this embodiment, off-grid startup can be achieved, and after startup, long-term off-grid operation can be maintained, realizing the multi-functional purpose of energy storage.

[0039] Furthermore, it should be noted that the startup mode of the wind turbine system described in this application is limited to off-grid startup, while the operating mode can include grid-connected operation and off-grid operation. Electrical loads can be added in both operating states. Once off-grid startup is complete, the wind turbine system can switch to one of the following two operating modes based on the status of the external power grid and actual needs: The first is the "grid-connected operation" mode. When the external power grid returns to normal, the wind turbine system transmits the electrical energy converted from wind energy to the grid, while the energy storage device 106 can charge, discharge, or provide grid auxiliary services according to grid instructions or preset strategies. The second is the "off-grid operation" mode. This is a continuous power supply state independent of the external power grid. After completing off-grid startup, if the external power grid continues to fail or according to preset application scenarios (such as supplying power to independent loads or important facilities in remote areas), the wind turbine system can operate as an independent microgrid power source without connecting to the main grid. At this point, the wind turbine 104 generates electricity, while the energy storage device 106 maintains the voltage and frequency stability of the entire off-grid system, smooths wind power fluctuations, and ensures reliable power supply to the electrical loads. The electrical loads can be energy-consuming loads specifically designed to dissipate excess power (such as resistor arrays), or local critical loads with practical functions (such as factories, data centers, or desalination equipment). This off-grid operation capability greatly expands the application scenarios of wind power generation, transforming it from a simple grid-connected power source into a distributed energy station with independent power supply capabilities.

[0040] In a specific example, in operating mode, the power supply switching device 107 determines the source of its input terminal based on the status of the power transmission line and the energy storage device 106.

[0041] Those skilled in the art will recognize that, in the above embodiments, by considering the state of the power transmission line and the energy storage device 106, a more stable power source can be selected to supply power to the auxiliary power system 109 in the operating mode, thereby providing continuous and stable power to the auxiliary power system, effectively avoiding the risk of wind turbine oscillation caused by power fluctuations, and improving the reliability of the system.

[0042] Optionally, in the above embodiments, to ensure the stability of the power supplied to the auxiliary power system 109 before and after switching, the power parameters output by the energy storage device 106 can be synchronized to the power parameters of the power transmission line before the switching operation at the input of the power supply switching device 107 is performed, thereby reducing device stress and improving system stability and safety. For example, in operating mode, the energy storage device 106 also absorbs power from the power transmission line. When the energy storage device 106 is about to be fully charged, the wind turbine system will prioritize using the energy storage device 106 to supply power to the auxiliary power system 109 so that the energy storage device 106 can continuously absorb energy. When the energy storage is simultaneously supplying power to both the power transmission line and the auxiliary power system 109 and is in a power-feeding state, the wind turbine system will prioritize using the power transmission line as the power supply for the auxiliary power system 109 to provide a long-term stable power supply. Furthermore, when either the energy storage or the power transmission line becomes unstable, the wind turbine system will select the relatively stable one as the power supply for the auxiliary power system 109 to ensure the normal operation of the wind turbine.

[0043] Furthermore, in this embodiment of the invention, the wind turbine 104 mentioned above is not limited to a single model, but includes, but is not limited to, a full-power wind turbine 110 and a doubly-fed wind turbine 112. Since the two differ significantly in topology, power output path, and control logic, they need to be adapted and optimized separately based on their own characteristics under the same off-grid start-up and operation objectives. The following describes embodiments of the full-power wind turbine 110 and the doubly-fed wind turbine 112 respectively.

[0044] It should be noted that, in this embodiment of the invention, the full-power wind turbine 110 and the doubly-fed wind turbine 112 are distinguished only by the connection method between the generator's power output path and the converter 103. More specifically, the full-power wind turbine 110 means that all the output power of its generator (whether synchronous or asynchronous) needs to be processed and converted by the converter 103 before being connected to the grid side; while the doubly-fed wind turbine 112 means that most of the power of its stator side 111 is directly connected to the grid side, and only a portion of the power of its rotor side 113 is exchanged and controlled through the converter 103. This difference in topology only affects the specific excitation and voltage build-up strategy of the converter 103 during off-grid startup, but the startup framework using the energy storage device 106 as an independent power source proposed in this invention is effectively applicable to both of these mainstream topologies. Therefore, any existing wind turbine with the same structure as the aforementioned full-power wind turbine 110 or doubly-fed wind turbine 112 can be classified as the full-power wind turbine 110 or doubly-fed wind turbine 112 involved in the embodiments of the present invention. For example, the full-power wind turbine 110 in the embodiments of the present invention can be a squirrel-cage induction generator, a permanent magnet synchronous generator, an electrically excited synchronous generator, etc., while the doubly-fed wind turbine 112 can be a wound-rotor induction generator, etc. Therefore, the scope of protection of the present invention is not limited to a specific motor model, but covers all wind turbine generator sets that conform to the above-described topological characteristics.

[0045] In one alternative embodiment, such as Figure 2 As shown, the wind turbine 107 is specifically a full-power wind turbine 110, and the stator side 111 of the full-power wind turbine 110 is connected to the low-voltage side of the transformer 101 through the converter 103.

[0046] In the full-power wind turbine generator 110 structure, its off-grid start-up principle is described as follows: After disconnecting the second switch 102, the energy storage device 106 first switches to the auxiliary power system 109 via the ATS, restoring the operation of subsystems such as yaw, pitch, cooling, lubrication, and monitoring, providing the necessary electrical and environmental conditions for turbine startup. Subsequently, when the wind speed exceeds the cut-in threshold, the wind turbine begins to drive the generator. Then, the energy storage device 106 establishes voltage on the DC bus of the converter 103 through the pre-charging device 108. The converter 103 then provides excitation current to the stator side 111. After the voltage on the stator side 111 reaches the preset voltage threshold, the pre-charging device 108 is disconnected, and the second switch 102 is closed, enabling the stator side 111 of the wind turbine generator to supply power to the grid normally.

[0047] The operating principle is as follows: The grid-side converter 103 converts the DC bus power into AC power through modulation and sends it to the low-voltage side of the transformer 101, thereby maintaining voltage matching and power balance with the auxiliary power system 109. During this process, the energy storage device 106 can flexibly adjust to charging or discharging mode according to the load and voltage status on the low-voltage side. For example, when the wind turbine output power is insufficient, the energy storage quickly releases energy to compensate; while when the wind turbine output power is excessive, the energy storage switches to an energy absorption state, thereby playing a role in peak shaving and valley filling and stabilizing the system.

[0048] In another alternative embodiment, such as Figure 3 As shown, the wind turbine 107 is specifically a doubly fed wind turbine 112. The rotor side 113 of the doubly fed wind turbine 112 is connected to the low-voltage side of the transformer through the converter 103, and the stator side 111 of the doubly fed wind turbine 112 is connected to the low-voltage side of the transformer 101.

[0049] In the structure of the doubly-fed induction generator (DFIG) wind turbine 112, its off-grid start-up principle is described as follows: After disconnecting the second switch 102, the energy storage device 106 first switches to the auxiliary power system 109 via the ATS, enabling the yaw, pitch, cooling, lubrication, and monitoring subsystems to resume operation, providing the necessary electrical and environmental conditions for turbine startup. Subsequently, when the wind speed exceeds the cut-in threshold, the wind turbine begins to drive the generator to rotate. Then, the energy storage device 106 establishes voltage on the DC bus of the converter 103 through the pre-charging device 108. The converter 103 then provides excitation current to the stator and rotor sides 113, thereby driving the stator side 111 to boost voltage. After the voltage on the stator side 111 reaches the preset voltage threshold, the pre-charging device 108 is disconnected, and the second switch 102 is closed, enabling the rotor side 113 of the wind turbine to supply power to the grid normally.

[0050] In some embodiments, in the above-described doubly-fed wind turbine 112 structure, due to the presence of both stator and rotor power generation sources, at the same low wind speed, the full-power wind turbine 110 may start normally, while the doubly-fed wind turbine 112 may fail to start due to wind speeds below the starting speed. To address the difficulty of starting the doubly-fed wind turbine 112 at low wind speeds, such as... Figure 4 As shown, a first switch 114 and a short-circuit switch 115 are also designed on the wind turbine system.

[0051] Specifically, the first switch 114 is installed on the power transmission line and located between the low-voltage side and the stator side 111 of the doubly-fed wind turbine 112; the short-circuit switch 115 is connected between the first switch 114 and the stator side 111 of the doubly-fed wind turbine 112; in the off-grid start-up mode, when the wind speed is higher than the first wind speed threshold, the first switch 114 is closed and the short-circuit switch 115 is open; when the wind speed is higher than the second wind speed threshold but lower than the first wind speed threshold, the first switch 114 is open and the short-circuit switch 115 is closed; wherein, the first wind speed threshold is higher than the second wind speed threshold.

[0052] In the above embodiment regarding low wind speed startup, a first switch 114 and a short-circuit switch 115 are added to the stator side 111 of the doubly-fed induction generator (DFIG). Using this method, the stator side 111 of the DFIG is short-circuited under low wind speed conditions, causing the energy output of the DFIG to be sent only from the rotor side 113 through the converter 103, thereby starting the DFIG in full-power turbine startup mode. This reduces system losses of the DFIG generator at low wind speeds and allows for control of the generator's power and speed via a simulated full-power converter, improving the generator's efficiency at low wind speeds and ultimately achieving off-grid startup of the DFIG at low wind speeds.

[0053] It should be noted that in the above embodiments, the wind turbine has requirements for the start-up wind speed. For example, under normal off-grid start-up conditions, the start-up wind speed of the doubly-fed induction generator (DFIG) is the first wind speed. Therefore, through the structural design for low-wind-speed start-up described above, the required start-up wind speed can be reduced to a second wind speed, which is lower than the first wind speed. Thus, the wind turbine can be started up under low-wind-speed conditions even when off-grid.

[0054] In an optional embodiment, the wind turbine system further includes a controller, or a host computer or other terminal device, which is the core for implementing the off-grid independent start-up and operation logic in this embodiment of the invention. The controller can be a centralized programmable logic controller (PLC), an industrial PC (IPC), or a distributed control system (DCS) consisting of a site-level host computer and local controllers for each component (such as a battery management system (BMS), converter controller, etc.). The controller or terminal device is connected to each component in the wind turbine system, enabling bidirectional data interaction with the wind turbine generator 107, energy storage device 106, power switching device 107, converter 103, and various key switches and sensors. As a central control core, this device monitors the status of each component in real time and, after judgment, issues corresponding control commands to each component. Throughout the entire operating mode, the controller continuously optimizes the charging and discharging strategy of the energy storage and the power supply source for auxiliary power to ensure system stability.

[0055] In this embodiment of the invention, in the event of a power grid failure, the power supply switching device 107 first switches the power source from the powerless grid side to the energy storage device 106. The energy storage device 106 then outputs electrical energy through two paths: one path supplies power to the auxiliary power system 109 of the wind turbine, ensuring that the wind turbine has basic operation and control capabilities and can rotate according to wind conditions; the other path charges the DC bus of the converter 103 through the pre-charging device 108, enabling it to operate. Once the converter 103 is energized and the wind turbine starts rotating, the converter 103 can excite the wind turbine generator, thereby establishing a stable output voltage on the generator side. Through this series of orderly scheduling of internal electrical energy, the system successfully utilizes the energy storage device 106 as the initial power source to start key components, including the auxiliary power system and the converter 103, and ultimately achieves voltage construction of the wind turbine generator itself, completing the independent startup process from complete shutdown to generating capacity, thus eliminating dependence on the external power grid.

[0056] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0057] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0058] Furthermore, the examples mentioned in the above embodiments can be freely combined, and any combination can be understood as an embodiment. The terms "embodiment" or "example" appearing in various locations in the specification do not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand that the embodiments described herein can be combined with other embodiments.

[0059] Another embodiment of the present invention relates to a control method for an independently start-up and operation wind turbine system, which can be applied in the controller of the wind turbine system or in terminal equipment such as a host computer.

[0060] In this embodiment of the invention, the wind turbine system involved in the above control method includes a wind turbine generator 104, an energy storage device 106, and a power supply switching device 107. The wind turbine generator 104 is connected to the low-voltage side of a transformer 101 via a power transmission line, and a converter 103 is provided on the power transmission line. The energy storage device 106 is connected to a first grid connection point on the power transmission line, and the first grid connection point is located between the low-voltage side of the transformer 101 and the converter 103. The power supply switching device 107 includes an input terminal connected to the energy storage device 106 and a second grid connection point on the power transmission line, respectively, and an input terminal connected to the auxiliary power system. 109. The output terminal of the pre-charging device 108 of the converter 103 is connected; the second grid connection point is located between the low-voltage side of the transformer 101 and the converter 103; the control method includes: after detecting grid disconnection, entering the off-grid start-up mode, controlling the power supply switching device 107 to switch the input terminal to the energy storage device 106; the energy storage device 106 supplies power to the auxiliary power system 109 to control the rotation of the wind turbine generator 104, and the energy storage device 106 also charges the converter 103 through the pre-charging device 108, the converter 103 excites the wind turbine generator 104, and constructs the output voltage of the wind turbine generator 104.

[0061] In some embodiments, the wind turbine 104 is a doubly-fed wind turbine 112, and the wind turbine system further includes a first switch 114, which is disposed on the power transmission line and located between the low-voltage side and the stator side 111 of the doubly-fed wind turbine 112; a short-circuit switch 115 is connected between the first switch 114 and the stator side 111 of the doubly-fed wind turbine 112; the control method further includes: in off-grid start-up mode, detecting the wind speed at the wind turbine; when the detected wind speed is higher than a first wind speed threshold, controlling the first switch 114 to be closed and controlling the short-circuit switch 115 to be open; when the detected wind speed is higher than a second wind speed threshold but lower than the first wind speed threshold, controlling the first switch 114 to be open and controlling the short-circuit switch 115 to be closed; wherein, the first wind speed threshold is higher than the second wind speed threshold.

[0062] In some embodiments, the wind turbine system further includes a converter 103 switch, which is disposed on the power transmission line and located between the low-voltage side of the transformer 101 and the converter 103; the control method further includes: after detecting that the output voltage of the wind turbine generator 104 has reached a preset voltage threshold, controlling the second switch 102 to switch from an open state to a closed state, and controlling the wind turbine system to enter the operating mode.

[0063] In some embodiments, the wind turbine system includes a third switch 105, and the energy storage device 106 is connected to a first grid connection point through the third switch 105; the control method further includes: after the wind turbine system enters the operating mode, controlling the third switch 105 to close; controlling the energy storage device 106 to be configured to a charging or discharging state according to the state of the first grid connection point; wherein, if the grid is disconnected and the wind turbine generator 104 generates surplus power, the energy storage device 106 is configured to a charging state.

[0064] In some embodiments, the control method further includes: in the operation mode, the power supply switching device 107 determines the source of the input terminal of the power supply switching device 107 based on the state of the power transmission line and the energy storage device 106.

[0065] In some embodiments, the wind turbine 104 is a full-power wind turbine 110, and the stator side 111 of the full-power wind turbine 110 is connected to the low-voltage side of the transformer 101 through the converter 103.

[0066] It is not difficult to see that this embodiment is a method embodiment corresponding to the above-described device embodiment, and this embodiment can be implemented in conjunction with the above-described device embodiment. The relevant technical details mentioned in the above-described method embodiments are still valid in this embodiment, and will not be repeated here to reduce repetition. Correspondingly, the relevant technical details mentioned in this embodiment can also be applied to the above-described method embodiments.

[0067] The steps described above are for clarity only. In practice, they can be combined into one step or some steps can be broken down into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent. Adding insignificant modifications or introducing insignificant designs to the algorithm or process, but without changing the core design of the algorithm and process, are also within the scope of protection of this patent.

[0068] Another embodiment of the present invention relates to a control device, such as Figure 5 As shown, it includes at least one processor 202; and a memory 201 communicatively connected to at least one processor 202; wherein the memory 201 stores instructions executable by at least one processor 202, the instructions being executed by at least one processor 202 to enable at least one processor 202 to perform the control method for independently starting and operating the wind turbine system as described above.

[0069] The memory 201 and processor 202 are connected via a bus, which can include any number of interconnecting buses and bridges. The bus connects various circuits of one or more processors 202 and memory 201 together. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further herein. A bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by processor 202 is transmitted over a wireless medium via an antenna, which further receives data and transmits it to processor 202.

[0070] Processor 202 is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory 201 can be used to store data used by processor 202 during operation.

[0071] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the method embodiments described above.

[0072] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0073] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A wind turbine system that can be started and operated independently, characterized in that, include: The wind turbine is connected to the low-voltage side of the transformer via a power transmission line, and the power transmission line is equipped with a converter. An energy storage device is connected to the first grid connection point on the power transmission line; The first grid connection point is located between the low-voltage side of the transformer and the converter; The power supply switching device includes an input terminal connected to the energy storage device and a second grid connection point on the power transmission line, respectively, and an output terminal connected to the auxiliary power system and the pre-charging device of the converter, respectively; the second grid connection point is located between the low-voltage side of the transformer and the converter; In the off-grid start-up mode, the power supply switching device switches the input terminal to the energy storage device. The energy storage device supplies power to the auxiliary power system to control the rotation of the wind turbine. The energy storage device also charges the converter through the pre-charging device. The converter excites the wind turbine to construct the output voltage of the wind turbine.

2. The independently start-up and operation fan system according to claim 1, characterized in that, The wind turbine is a doubly-fed wind turbine; the wind turbine system also includes: The first switch is installed on the power transmission line and located between the low-voltage side and the stator side of the doubly-fed wind turbine. A short-circuit switch is connected between the first switch and the stator side of the doubly-fed wind turbine. In the off-grid start-up mode, when the wind speed is higher than the first wind speed threshold, the first switch is closed and the short-circuit switch is open; when the wind speed is higher than the second wind speed threshold but lower than the first wind speed threshold, the first switch is open and the short-circuit switch is closed. The first wind speed threshold is higher than the second wind speed threshold.

3. The independently start-up and operation fan system according to claim 1, characterized in that, include: The second switch is installed on the power transmission line and located between the low-voltage side of the transformer and the converter; After the output voltage of the wind turbine generator reaches a preset voltage threshold, the second switch switches from the open state to the closed state, and the wind turbine system switches from the off-grid start-up mode to the operating mode.

4. The independently start-up and operation fan system according to claim 3, characterized in that, include: The third switch connects the energy storage device to the first grid connection point. After the wind turbine system enters the operating mode, the third switch is switched to the closed state, and the energy storage device is configured to charge or discharge state according to the state of the first grid connection point. If the power grid is disconnected and the wind turbine generates surplus power, the energy storage device is configured to be in a charging state.

5. The independently start-up and operation fan system according to claim 4, characterized in that, In the operating mode, the power supply switching device determines the source of its input terminal based on the status of the power transmission line and the energy storage device.

6. The independently start-up and operation fan system according to claim 1, characterized in that, The wind turbine is a full-power wind turbine, and the stator side of the full-power wind turbine is connected to the low-voltage side of the transformer through the converter.

7. A control method for an independently start-up and operation fan system, characterized in that, The wind turbine system includes a wind turbine generator, an energy storage device, and a power supply switching device. The wind turbine generator is connected to the low-voltage side of a transformer via a power transmission line, and a converter is installed on the power transmission line. The energy storage device is connected to a first grid connection point on the power transmission line, which is located between the low-voltage side of the transformer and the converter. The power supply switching device includes an input terminal connected to the energy storage device and a second grid connection point on the power transmission line, and an output terminal connected to an auxiliary power system and a pre-charging device for the converter. The second grid connection point is located between the low-voltage side of the transformer and the converter; the control method includes: After detecting that the power grid is disconnected, the off-grid start-up mode is entered, and the power supply switching device is controlled to switch the input terminal to the energy storage device. The energy storage device supplies power to the auxiliary power system to control the rotation of the wind turbine. The energy storage device also charges the converter through the pre-charging device. The converter excites the wind turbine to generate the output voltage of the wind turbine.

8. The control method for an independently started and operated wind turbine system according to claim 7, characterized in that, The wind turbine is a doubly fed wind turbine, and the wind turbine system also includes a first switch, which is set on the power transmission line and located between the low-voltage side and the stator side of the doubly fed wind turbine. A short-circuit switch is connected between the first switch and the stator side of the doubly-fed wind turbine; the control method further includes: In the off-grid start-up mode, the wind speed at the wind turbine generator is detected; When the wind speed is detected to be higher than the first wind speed threshold, the first switch is controlled to be closed and the short-circuit switch is controlled to be open. When the wind speed is detected to be higher than the second wind speed threshold but lower than the first wind speed threshold, the first switch is controlled to be open and the short-circuit switch is controlled to be closed. The first wind speed threshold is higher than the second wind speed threshold.

9. The control method for an independently started and operated wind turbine system according to claim 7, characterized in that, The wind turbine system also includes a second switch, which is installed on the power transmission line and located between the low-voltage side of the transformer and the converter; the control method further includes: After detecting that the output voltage of the wind turbine has reached a preset voltage threshold, the second switch is controlled to switch from the open state to the closed state, thereby controlling the wind turbine system to enter the operating mode.

10. The control method for an independently started and operated wind turbine system according to claim 9, characterized in that, The wind turbine system includes a third switch, and the energy storage device is connected to the first grid connection point through the third switch; the control method further includes: After the fan system enters the operating mode, it controls the third switch to close. The energy storage device is configured to charge or discharge state according to the status of the first grid connection point. If the power grid is disconnected and the wind turbine generates surplus power, the energy storage device is configured to be in a charging state.

11. The control method for an independently started and operated wind turbine system according to claim 10, characterized in that, The control method further includes: In the operating mode, the source of the input terminal of the power supply switching device is selectively switched based on the status of the power transmission line and the energy storage device.

12. A control device for a fan system, characterized in that, include: At least one processor; And a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform a control method for independently starting and operating a wind turbine system as described in any one of claims 7 to 11.

13. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the control method for the independently started and operated wind turbine system as described in any one of claims 7 to 11.

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