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 transformer at least comprises a high-voltage side, a first low-voltage side and a second low-voltage side, and the high-voltage side is connected to a power grid; the wind driven generator is connected with the first low-voltage side through a power transmission line, and a converter is arranged on the power transmission line; the power distribution system is connected with the second low-voltage side through a first switch and is connected with a pre-charging device of the wind driven generator; the energy storage device is connected to a first grid connection point between the power distribution system and the first switch; when the fan system is in an off-grid starting mode, the first switch is switched from a closed state to an open state, 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 pre-charges the converter through the pre-charging device, the converter excites the wind driven generator, and the output voltage of the wind driven generator is constructed. 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 embodiments of the present invention relate to the field of wind turbines, and particularly to wind turbine systems, control methods, control equipment and media that can be started and operated independently. Background Technology

[0002] As wind power continues to account for an increasing proportion of the global energy mix, the safe and stable operation of wind farms is crucial to the reliability of the power grid.

[0003] However, starting a wind turbine requires the auxiliary power system to rotate the turbine while the power supply is on before voltage can be established. When the grid loses power, the wind turbine's auxiliary power system (including yaw, pitch, cooling, control cabinet, and status monitoring system) also loses power, making it difficult for the wind turbine to start independently off-grid in the event of a complete grid power outage. Summary of the Invention

[0004] The purpose of this invention is to provide a wind turbine system, control method, control equipment, and medium that can start and operate independently, enabling the wind turbine to start independently off-grid in the event of a complete power outage.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide an independently startable and operable wind turbine system, comprising: a transformer, including at least a high-voltage side, a first low-voltage side, and a second low-voltage side, wherein the high-voltage side is connected to the power grid; a wind turbine generator, connected to the first low-voltage side via a power transmission line, wherein a converter is provided on the power transmission line; a power distribution system, connected to the second low-voltage side via a first switch and connected to a pre-charging device of the wind turbine generator; and an energy storage device, connected to a first grid connection point between the power distribution system and the first switch; wherein, in off-grid start-up mode, the first switch switches from a closed state to an open state, the energy storage device supplies power to the auxiliary power system to control the rotation of the wind turbine generator, the energy storage device also pre-charges the converter via the pre-charging device, and the converter excites the wind turbine generator to construct the output voltage of the wind turbine generator.

[0006] Embodiments of the present invention also provide a control method for an independently start-up and operation wind turbine system. The wind turbine system includes a transformer, a wind turbine generator, a power distribution system, and an energy storage device. The transformer includes at least a high-voltage side, a first low-voltage side, and a second low-voltage side. The high-voltage side is connected to the power grid. The wind turbine generator is connected to the first low-voltage side via a power transmission line, and a converter is provided on the power transmission line. The power distribution system is connected to the second low-voltage side via a first switch and is also connected to a pre-charging device of the wind turbine generator. The energy storage device is connected to a first grid connection point between the power distribution system and the first switch. The control method includes: upon detecting grid disconnection, entering an off-grid start-up mode; the energy storage device supplies power to the auxiliary power system to control the rotation of the wind turbine generator; the energy storage device also charges the converter via the pre-charging device; the converter excites the wind turbine generator to construct the output voltage of the wind turbine generator.

[0007] Embodiments of the present invention also provide a control device for a wind turbine system, comprising: 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 the control method for independently starting and operating the wind turbine system as described above.

[0008] Embodiments of the present invention also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the control method for an independently started and operated wind turbine system as described above.

[0009] In this embodiment of the invention, a transformer is used to electrically isolate and separate the high-voltage grid side, the first low-voltage side connected to the wind turbine generator, and the second low-voltage side connected to the wind turbine power distribution system, enhancing the safety of the wind turbine system during off-grid startup. In the event of a grid power failure, the first switch opens, decoupling the power distribution system from the de-energized second low-voltage side of the transformer. At this time, the energy storage device acts as an independent starting power source, outputting electrical energy simultaneously through two paths: the first path directly supplies power to the power distribution system to drive auxiliary electrical systems such as yaw and pitch, enabling the wind turbine generator to have basic operational capabilities such as responding to wind speed and starting rotation; the second path charges the converter on the wind turbine side power transmission line through a pre-charging device on the power distribution system. Once the converter is energized and the wind turbine begins to rotate, the converter can excite the wind turbine generator, thereby successfully establishing a stable output voltage on the generator side. Through this series of orderly scheduling of internal electrical energy, the system successfully used the energy storage device as the initial power source to start up key components including auxiliary power and converters, and finally realized the voltage construction of the wind turbine itself, completing the independent startup process from complete shutdown to power generation capability, and getting rid of dependence on the external power grid. Attached Figure Description

[0010] 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.

[0011] 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;

[0012] 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;

[0013] 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;

[0014] 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;

[0015] Figure 5 This is a structural diagram of a control device provided according to an embodiment of the present invention. Detailed Implementation

[0016] 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.

[0017] 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. This then establishes the voltage at the generator end, enabling grid connection. 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.

[0018] 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.

[0019] 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.

[0020] One embodiment of the present invention relates to a wind turbine system that can be started and operated independently, including a transformer 101, which includes at least a high-voltage side 102, a first low-voltage side 103, and a second low-voltage side 104, with the high-voltage side 102 connected to the power grid; a wind turbine generator 107 connected to the first low-voltage side 103 via a power transmission line, with a converter 106 installed on the power transmission line; a power distribution system connected to the second low-voltage side 104 via a first switch 108, and connected to a pre-charging device 110 of the wind turbine generator 107; and an energy storage device 111 connected to a first grid connection point between the power distribution system and the first switch 108; wherein, in the off-grid start-up mode, the first switch 108 switches from a closed state to an open state, and the energy storage device 111 supplies power to the auxiliary power system 109 to control the rotation of the wind turbine generator 107. The energy storage device 111 also pre-charges the converter 106 via the pre-charging device 110, and the converter 106 excites the wind turbine generator 107 to construct the output voltage of the wind turbine generator 107. In this embodiment of the invention, a transformer 101 is used to electrically isolate and separate the high-voltage grid side, the first low-voltage side 103 connected to the wind turbine generator 107, and the second low-voltage side 104 connected to the wind turbine power distribution system, thereby enhancing the safety of the wind turbine system during off-grid startup. In the event of a grid power failure, the first switch 108 is opened, decoupling the power distribution system from the de-energized second low-voltage side 104 of the transformer. At this time, the energy storage device 111 acts as an independent starting power source, outputting electrical energy simultaneously through two paths: the first path is to directly supply power to the power distribution system to drive auxiliary electrical systems 109 such as yaw and pitch control, enabling the wind turbine generator 107 to have basic operational capabilities such as responding to wind speed and starting rotation; the second path is to charge the converter 106 on the wind turbine side power transmission line through the pre-charging device 110 on the power distribution system. Once the converter 106 is energized and the wind turbine starts to rotate, the converter 106 can excite the wind turbine generator 107, thereby successfully establishing a stable output voltage on the generator side. Through this series of orderly scheduling of internal electrical energy, the system successfully used the energy storage device 111 as the initial power source to start up key components including auxiliary power and converter 106, and finally realized the voltage construction of the wind turbine generator 107 itself, completing the independent start-up process from complete shutdown to power generation capability, and getting rid of dependence on the external power grid.

[0021] 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.

[0022] like Figure 1As shown, the wind turbine system includes a wind turbine generator 107, an energy storage device 111, a converter 106, an auxiliary power system 109, a pre-charging device 110, a transformer 101, a first switch 108, and a third switch 105, forming a complete system capable of self-starting and continuous operation independently of the power grid.

[0023] Transformer 101 includes at least a high-voltage side 102, a first low-voltage side 103, and a second low-voltage side 104, with the high-voltage side 102 connected to the power grid. Specifically, transformer 101 is a key component for enabling independent off-grid startup and stable grid-connected operation of wind turbines.

[0024] In a specific example, transformer 101 includes at least three independent windings, clearly defining three functional domains physically and electrically: a high-voltage domain connecting to the external power grid, a first low-voltage domain for the power output of wind turbine generator 107, and a second low-voltage domain for supplying power to the auxiliary power system 109 inside the wind turbine. Compared to existing dual-winding transformers, transformer 101 in this embodiment provides a higher level of electrical isolation. When a short circuit or other fault occurs on either low-voltage side (e.g., auxiliary power system 109), the voltage and current surges to the other low-voltage side (generator main circuit) are greatly suppressed, thereby significantly improving the operational reliability and fault ride-through capability of the entire wind turbine system. Secondly, the voltage levels of the two low-voltage windings can be independently designed and optimized according to load characteristics. For example, the first low-voltage side 103 can be designed to match the output voltage of the wind turbine generator 107 (e.g., 1140V, 690V), while the second low-voltage side 104 can be designed to be adapted to the energy storage voltage level (e.g., 690V, 400V), providing isolation for the main circuit of the energy storage wind turbine generator 107, eliminating the need for an additional isolation transformer, simplifying the system structure, and reducing costs. More importantly, this structure lays the foundation for the off-grid start-up strategy of this invention. When the grid loses voltage, by disconnecting the first switch 108 between the second low-voltage side 104 and the distribution system, the "microgrid" composed of the energy storage device 111 and the auxiliary power system 109 can be completely decoupled from the transformer, avoiding the risk of backfeeding power to the de-energized grid side, and creating the necessary boundary conditions for the energy storage device 111 to independently and safely precharge the auxiliary power system 109 and the converter 106.

[0025] In an optional embodiment, the transformer 101 may have more than three windings. In addition to the one high-voltage side and two low-voltage sides, it may include one or more additional windings (e.g., a third low-voltage side, a fourth low-voltage side, etc.) to construct a central hub integrating a multi-functional electrical interface. For example, this additional winding may be designed, 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] The wind turbine 107 is connected to the first low-voltage side 103 via a power transmission line, on which a converter 106 is installed. Specifically, the wind turbine 107 is electrically connected to the first low-voltage side 103 of the three-double-winding transformer via the converter 106, and the power transmission carrier is the power transmission line. Under normal operating conditions, the wind turbine 107 can exchange power with the grid through the transformer 101. However, when the grid is in a power outage state, the wind turbine itself cannot rely on the preceding voltage provided by the grid to drive the auxiliary system and the DC bus of the converter 106. Therefore, it needs to rely on the energy storage device 111 to achieve independent startup.

[0027] The auxiliary power system 109 is connected to the second low-voltage side 104 via a first switch 108 and to the pre-charging device 110 of the wind turbine generator 107. Specifically, the auxiliary power system 109 includes a series of auxiliary devices necessary for the normal operation of the wind turbine generator 107, while the first switch 108 is the core component for safely switching the wind turbine between grid-connected operation mode and off-grid start-up mode. During grid-connected operation, the first switch 108 is closed, and the auxiliary power system 109 obtains stable power from the second low-voltage side 104 of the transformer 101 through this connection; this power ultimately comes from the power grid. When the grid loses voltage and off-grid start-up is required, the first switch 108 actively disconnects, electrically isolating the entire auxiliary power system 109 from the transformer side, preventing the energy from the energy storage device 111 from being fed back to the grid, and ensuring the independence and safety of the start-up process. Simultaneously, the distribution network where the auxiliary power system 109 is located also provides a power interface for the pre-charging device 110 of the converter 106 of the wind turbine generator 107. In off-grid start-up mode, the electrical energy provided by the energy storage device 111 supplies power to systems such as yaw and pitch, enabling them to operate, and also flows through this path to the pre-charging device 110. After receiving the electrical energy, the pre-charging device 110 performs controllable and gradual charging of the DC bus capacitor of the converter 106 to establish the operating voltage required for the subsequent excitation generator.

[0028] Energy storage device 111 is connected to the first grid connection point between the power distribution system and the first switch 108. Specifically, energy storage device 111 is designed to support not only off-grid start-up mode but also to switch to operating mode after the wind turbine starts up. In off-grid start-up mode, the first switch 108 is open, and the electrical energy output by energy storage device 111 is directly conducted to auxiliary power system 109 and pre-charging device 110 through power supply switching device. When the wind turbine completes off-grid start-up and enters the operating stage, the first switch 108 is closed, and energy storage device 111 can serve as a backup power source. It can be flexibly configured to charge or discharge state according to the power status generated by wind turbine generator 107, achieving dynamic energy balance and thus avoiding fluctuations in auxiliary power system 109 caused by unstable wind turbine power supply.

[0029] It should be noted that the energy storage device 111 mentioned in this embodiment of the invention can be configured in a variety of ways. On the one hand, it can be a new energy storage device 111 specifically designed for off-grid start-up. In this case, the core parameters of the energy storage device 111, 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 106 pre-charging. Furthermore, this energy storage device 111 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.

[0030] 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. That is, in a wind-storage integrated unit primarily designed for grid-connected operation and providing grid-friendly services, the functions can be expanded by using the three-winding system, dedicated electrical isolation and connection circuits, and integrating corresponding black-start control strategies into the wind turbine system. This allows the energy storage device 111 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.

[0031] Furthermore, this application utilizes the energy storage device 111 as the power supply for the auxiliary power system 109 and the pre-charging device 110, 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 111 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 106 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 110. 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 106 and the wind turbine side.

[0032] In this embodiment of the invention, the wind turbine system constructed by the above structure includes two modes: off-grid start-up mode and operating mode. In off-grid start-up mode, the first switch 108 switches from a closed state to an open state, and the energy storage device 111 supplies power to the auxiliary power system 109 to control the rotation of the wind turbine generator 107. The energy storage device 111 also precharges the converter 106 through the pre-charging device 110, and the converter 106 excites the wind turbine generator 107 to construct the output voltage of the wind turbine generator 107.

[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 106: first, energizing the auxiliary power system 109 to rotate the wind turbine; and second, pre-charging the converter 106 to enable its excitation capability. The converter 106 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 third switch 105, which is located between the first low-voltage side 103 and the converter 106; after the output voltage of the wind turbine generator 107 reaches the preset voltage threshold, the third switch 105 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 107 reaching a preset rated voltage, which is set with reference to the configuration of the wind turbine 107 itself. In some scenarios, the rated voltage setting needs to be considered in conjunction with the specific scenario. Only after the output voltage of the wind turbine 107 is boosted to the preset threshold under the control of the converter 106 can the wind turbine be connected to the grid.

[0036] In a specific example, the wind turbine system also has an operating mode. After the wind turbine system enters the operating mode, the first switch 108 is switched to the closed state, and the energy storage device 111 is configured to charge or discharge state according to the state of the second low-pressure side 104.

[0037] As those skilled in the art will understand, in the above embodiments, after the wind turbine system enters the operating mode, by closing the previously disconnected first switch 108, the power supply circuit consisting of the energy storage device 111 and the power distribution system is electrically re-established with the second low-voltage side 104 of the transformer 101. This closing action allows the energy storage device 111 to be flexibly configured to charge or discharge according to the real-time state of the second low-voltage side 104. When the transformer side is stable, the energy storage device 111 can absorb electrical energy for charging; and when there is demand on the transformer side, the energy storage device 111 can discharge into the circuit.

[0038] In an optional embodiment, two overcurrent protection devices are also connected to the transformer side. The first overcurrent protection device, located on the first low-voltage side 103, is used to prevent power anomalies on the wind turbine generator 107 side; the second overcurrent protection device, located on the second low-voltage side 104, is used to prevent power anomalies in the power distribution system. This dual and independent protection configuration fully utilizes the structural advantage of the transformer 101, which physically isolates the main power circuit and auxiliary power circuit, achieving precise and hierarchical protection for different electrical circuits, thereby significantly improving the overall safety and reliability of the system.

[0039] As those skilled in the art will recognize, this dual and independent protection configuration fully leverages the structural advantage of transformer 101, which physically isolates the main power circuit and auxiliary power circuit, achieving precise and hierarchical protection for different electrical circuits, thereby significantly improving the overall safety and reliability of the system. The first overcurrent protection device primarily monitors and protects the main power circuit from the wind turbine generator 107 to the transformer. Once a short circuit or severe overload is detected in the generator, converter 106, or power transmission cable, it will quickly activate, disconnecting the faulty circuit, thus protecting the transformer and the power grid from impact and confining the fault within the generator system. The second overcurrent protection device focuses on monitoring and protecting the power distribution network, including the auxiliary power system 109. When a load within the power distribution system (such as a cooling fan, hydraulic pump motor, etc.) fails, only the second overcurrent protection device will trip, thus isolating the fault point without affecting the main power output of the first low-voltage side 103.

[0040] 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 "grid-connected operation" mode. When the external power grid returns to normal, the wind turbine system transmits the electrical energy converted from wind power to the grid, while the energy storage device 111 can charge, discharge, or provide grid auxiliary services according to grid instructions or preset strategies. The second is "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. In this case, the wind turbine generator 107 is responsible for generating electricity, while the energy storage device 111 is responsible for maintaining the voltage and frequency stability of the entire off-grid system, smoothing wind power fluctuations, and ensuring reliable power supply to the electrical loads. Electrical loads can be energy-consuming loads specifically designed to consume excess electrical energy (such as resistor arrays), or they can be local critical loads with practical functions (such as factories, data centers, or seawater 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.

[0041] In a specific example, if the grid is off-grid and the wind turbine 107 generates surplus power, the energy storage device 111 is configured to a charging state. Specifically, after the wind turbine 107 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 107 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 111 as a dynamic power balancing unit: when surplus power is detected, the energy storage device 111 is configured to a charging state to absorb the surplus power generated by the off-grid operation of the wind turbine 107. Thus, using only the energy storage device 111 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.

[0042] Furthermore, in this embodiment of the invention, the wind turbine 107 mentioned above is not limited to a single model, but includes, but is not limited to, a full-power wind turbine 112 and a doubly-fed wind turbine 114. 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 112 and the doubly-fed wind turbine 114 respectively.

[0043] It should be noted that, in this embodiment of the invention, the distinction between the full-power wind turbine 112 and the doubly-fed wind turbine 114 lies only in the connection method between the generator's power output path and the converter 106. More specifically, the full-power wind turbine 112 refers to a generator (whether synchronous or asynchronous) whose entire output power must be processed and converted by the converter 106 before being connected to the grid; while the doubly-fed wind turbine 114 refers to a generator whose stator side 113 power is directly connected to the grid, with only a portion of the rotor side 115 power being exchanged and controlled by the converter 106. This difference in topology only affects the specific excitation and voltage build-up strategy of the converter 106 during off-grid startup, but the startup framework using the energy storage device 111 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 112 or doubly-fed wind turbine 114 can be classified as the full-power wind turbine 112 or doubly-fed wind turbine 114 involved in the embodiments of the present invention. For example, the full-power wind turbine 112 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 114 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.

[0044] In one alternative embodiment, such as Figure 2 As shown, the wind turbine 107 is specifically a full-power wind turbine 112, and the stator side 113 of the full-power wind turbine 112 is connected to the first low-voltage side 103 through the converter 106.

[0045] In the structure of the full-power wind turbine generator 112, its off-grid start-up principle is described as follows: When the third switch 105 is disconnected, the energy storage device 111 supplies power to the auxiliary power system 109, 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. Then, the energy storage device 111 establishes voltage on the DC bus of the converter 106 through the pre-charging device 110. The converter 106 then provides excitation current to the stator side 113. Once the voltage on the stator side 113 reaches the preset voltage threshold, the pre-charging device 110 is disconnected, and the third switch 105 is closed, allowing the stator side 113 of the wind turbine generator to supply power to the grid normally.

[0046] The operating principle is as follows: The grid-side converter 106 converts the DC bus power into AC power through modulation and sends it to the first low-voltage side 103 of the transformer 101, thereby maintaining voltage matching and power balance with the auxiliary power system 109. During this process, the energy storage device 111 can flexibly adjust to charging or discharging mode according to the load and voltage status of the second low-voltage side 104. 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.

[0047] In another alternative embodiment, such as Figure 3 As shown, the wind turbine 107 is specifically a doubly fed wind turbine 114. The rotor side 115 of the doubly fed wind turbine 114 is connected to the first low-voltage side 103 of the transformer 101 through the converter 106, and the stator side 113 of the doubly fed wind turbine 114 is connected to the low-voltage side of the double-winding transformer.

[0048] In the structure of the doubly-fed wind turbine generator 114, its off-grid start-up principle is described as follows: After disconnecting the third switch 105, the energy storage device 111 first supplies power to the auxiliary power system 109, 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 111 establishes voltage on the DC bus of the converter 106 through the pre-charging device 110. The converter 106 then provides excitation current to the stator and rotor sides 115, thereby driving the stator side 113 to boost voltage. After the voltage on the stator side 113 reaches the preset voltage threshold, the pre-charging device 110 is disconnected, and the third switch 105 is closed, enabling the rotor side 115 of the wind turbine generator to supply power to the grid normally.

[0049] In some embodiments, in the above-described doubly-fed wind turbine 114 structure, due to the presence of both stator and rotor power generation sources, at the same low wind speed, the full-power wind turbine 112 may start normally, while the doubly-fed wind turbine 114 may fail to start due to wind speeds below the starting speed. To address the difficulty of starting the doubly-fed wind turbine 114 at low wind speeds, such as... Figure 4 As shown, a second switch 117 and a short-circuit switch 116 are also designed on the wind turbine system.

[0050] Specifically, the second switch 117 is connected between the first low-voltage side 103 and the stator side 113 of the doubly-fed wind turbine 114; the short-circuit switch 116 is connected between the second switch 117 and the stator side 113 of the doubly-fed wind turbine 114; in off-grid start-up mode, when the wind speed is higher than the first wind speed threshold, the second switch 117 is closed and the short-circuit switch 116 is open; when the wind speed is higher than the second wind speed threshold but lower than the first wind speed threshold, the second switch 117 is open and the short-circuit switch 116 is closed; wherein, the first wind speed threshold is higher than the second wind speed threshold.

[0051] In the above embodiment regarding low wind speed start-up, a second switch 117 and a short-circuit switch 116 are added to the stator side 113 of the doubly-fed induction generator (DFIG). Using this method, the stator side 113 of the DFIG is short-circuited under low wind speed conditions, so that the energy output of the DFIG is only sent from the rotor side 115 through the converter 106, thereby starting the DFIG in full-power turbine start-up mode. This reduces system losses of the DFIG generator at low wind speeds and improves the power generation efficiency of the DFIG generator at low wind speeds by controlling the generator's power and speed through a simulated full-power converter, ultimately achieving off-grid start-up of the DFIG at low wind speeds.

[0052] 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.

[0053] 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 111, power supply switching device, converter 106, 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.

[0054] In this embodiment of the invention, a transformer 101 is used to electrically isolate and separate the high-voltage grid side, the first low-voltage side 103 connected to the wind turbine generator, and the second low-voltage side 104 connected to the wind turbine power distribution system, thereby enhancing the safety of the wind turbine system during off-grid startup. In the event of a grid power failure, the first switch 108 is opened, decoupling the power distribution system from the de-energized second low-voltage side 104 of the transformer. At this time, the energy storage device 111 acts as an independent starting power source, outputting electrical energy simultaneously through two paths: the first path is to directly supply power to the power distribution system to drive auxiliary electrical systems 109 such as yaw and pitch control, enabling the wind turbine generator to have basic operational capabilities such as responding to wind speed and starting rotation; the second path is to charge the converter 106 on the wind turbine side power transmission line through the pre-charging device 110 on the power distribution system. Once the converter 106 is energized and the wind turbine starts to rotate, the converter 106 can excite the wind turbine generator, thereby successfully establishing a stable output voltage on the generator side. Through this series of orderly scheduling of internal electrical energy, the system successfully used the energy storage device 111 as the initial power source to start up key components including auxiliary power and converter 106, and finally realized the voltage construction of the wind turbine itself, completing the independent start-up process from complete shutdown to power generation capability, and getting rid of dependence on the external power grid.

[0055] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] In this embodiment of the invention, the wind turbine system involved in the above control method includes a transformer 101, a wind turbine generator 107, a power distribution system, and an energy storage device 111. The transformer 101 includes at least a high-voltage side 102, a first low-voltage side 103, and a second low-voltage side 104. The high-voltage side 102 is connected to the power grid. The wind turbine generator 107 is connected to the first low-voltage side 103 via a power transmission line, and a converter 106 is provided on the power transmission line. The power distribution system is connected to the second low-voltage side 104 via a first switch 108. The pre-charging device 110 is connected to the wind turbine generator 107; the energy storage device 111 is connected to the first grid connection point between the power distribution system and the first switch 108; the control method includes: after detecting that the grid is off-grid, entering the off-grid start mode, the energy storage device 111 supplies power to the auxiliary power system 109 to control the rotation of the wind turbine generator 107, the energy storage device 111 also charges the converter 106 through the pre-charging device 110, the converter 106 excites the wind turbine generator 107, and constructs the output voltage of the wind turbine generator 107.

[0060] In some embodiments, the wind turbine 107 is a doubly-fed wind turbine 114, and the wind turbine system further includes a second switch 117 connected between the first low-voltage side 103 and the stator side 113 of the doubly-fed wind turbine 114; a short-circuit switch 116 connected between the second switch 117 and the stator side 113 of the doubly-fed wind turbine 114; 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 second switch 117 to be closed and controlling the short-circuit switch 116 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 second switch 117 to be open and controlling the short-circuit switch 116 to be closed; wherein, the first wind speed threshold is higher than the second wind speed threshold.

[0061] In some embodiments, the wind turbine system further includes a converter 106 switch, and a third switch 105 is disposed between the first low-voltage side 103 and the converter 106; the control method further includes: after detecting that the output voltage of the wind turbine generator 107 has reached a preset voltage threshold, controlling the third switch 105 to switch from an open state to a closed state, and controlling the wind turbine system to enter the operating mode.

[0062] In some embodiments, the control method further includes: after the wind turbine system enters the operating mode, controlling the first switch 108 to close; controlling the energy storage device 111 to be configured to charge or discharge state according to the state of the two low-voltage sides; wherein, if the grid is disconnected and the wind turbine generator 107 generates surplus power, the energy storage device 106 is configured to charge state.

[0063] In some embodiments, the wind turbine 107 is a full-power wind turbine 112, and the stator side 113 of the full-power wind turbine 112 is connected to the first low-voltage side 103 of the transformer 101 through the converter 106.

[0064] In some embodiments, the wind turbine system further includes a first overcurrent protection device located on the first low-voltage side 103 to prevent power abnormalities on the wind turbine generator side; and a second overcurrent protection device located on the second low-voltage side 104 to prevent power abnormalities in the power distribution system.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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: A transformer includes at least a high-voltage side, a first low-voltage side, and a second low-voltage side, wherein the high-voltage side is connected to a power grid. A wind turbine is connected to the first low-voltage side via a power transmission line, and a converter is provided on the power transmission line; The power distribution system is connected to the second low-voltage side via a first switch and to the pre-charging device of the wind turbine. An energy storage device is connected to the first grid connection point between the power distribution system and the first switch; In the off-grid start-up mode, the first switch switches from closed to open, the energy storage device supplies power to the auxiliary power system to control the rotation of the wind turbine, the energy storage device also precharges the converter through the pre-charging device, and the converter excites the wind turbine to build 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 second switch is connected between the first low-pressure side and the stator side of the doubly-fed wind turbine. The short-circuit switch is connected between the second 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 second 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 second 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 third switch is located between the first low-voltage side and the converter; After the output voltage of the wind turbine generator reaches a preset voltage threshold, the third 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 1, characterized in that, After the wind turbine system enters the operating mode, the first 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 dual-winding transformer side. 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 1, characterized in that, include: The first overcurrent protection device is located on the first low-voltage side and is used to prevent power abnormalities on the wind turbine side. The second overcurrent protection device is located on the second low-voltage side and is used to prevent power abnormalities in the power distribution system.

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 first low-voltage side 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 transformer, a wind turbine generator, a power distribution system, and an energy storage device. The transformer includes at least a high-voltage side, a first low-voltage side, and a second low-voltage side. The high-voltage side is connected to the power grid. The wind turbine generator is connected to the first low-voltage side via a power transmission line, and a converter is provided on the power transmission line. The power distribution system is connected to the second low-voltage side via a first switch and is also connected to the pre-charging device of the wind turbine generator. The energy storage device is connected to the first grid connection point between the power distribution system and the first switch; The control method includes: After detecting grid disconnection, the system enters off-grid start-up mode. 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 build 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 further includes a second switch connected between the first low-voltage side and the stator side of the doubly-fed wind turbine; a short-circuit switch connected in parallel between the second 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 second 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 second 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 further includes a third switch, which is disposed between the first low-pressure side 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 third 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 control method further includes: After the fan system enters the operating mode, it controls the first switch to close. The energy storage device is configured to charge or discharge state according to the state of the two low-voltage sides. 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. 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 10.

12. 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 10.

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