Standby power supply system of wind generating set and wind generating set

Abstract

The invention discloses a standby power supply system of a wind generating set and the wind generating set, and relates to the field of wind power generation. When the power grid stops supplying power to the wind generating set, the energy storage equipment is started and switched to a discharge mode to supply power to self-powered equipment of the wind generating set; the main control system sends a black-start instruction to the converter and controls the energy storage equipment to supply power to the converter, and the converter responds to the black-start instruction and controls output of a generator of the wind generating set; when the output meets the preset grid connection condition, disconnecting the power supply connection between the energy storage equipment and the wind generating set, and enabling the wind generating set to enter a self-generating and self-using state; and controlling the energy storage equipment to be connected with the wind generating set, switching the energy storage equipment to a charging mode, and charging the energy storage equipment by using electric power generated by the wind generating set. The power generated by the wind turbine generator is used for storing energy for next black start, the problem of insufficient power of a standby power supply is avoided, recycling of energy storage equipment is achieved, and energy consumption is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of wind power generation, and in particular to a backup power supply system for a wind turbine generator set and a wind turbine generator set. Background Art

[0002] Wind turbines, systems that convert wind kinetic energy into electrical energy, have been widely used for their clean and renewable advantages. Due to the characteristics of wind turbines, wind farms are often built in remote areas. However, wind turbines rely on the power grid for operation. Therefore, if the power grid collapses due to natural damage, equipment aging, or other factors, the wind turbine will not be able to restart in time. In severe cases, the wind turbine will shut down completely. Prolonged downtime can cause mechanical damage, control system failures, and safety risks. Therefore, wind turbines are often equipped with backup power supplies to support black starts and quickly restore power to the unit.

[0003] At present, the backup power supply of wind turbines usually adopts diesel generators, and black start is achieved through diesel generators. However, fuel generators need fuel as an energy source. When the fuel is consumed, the unit will completely lose the backup power supply. Therefore, the current wind turbines have the problem of high backup power supply energy consumption and insufficient power of the backup power supply, which leads to black start interruption. Summary of the Invention

[0004] In view of the above problems, the present application provides a backup power supply system for a wind turbine generator set and a wind turbine generator set, so as to achieve the purpose of reducing the energy consumption of the backup power supply while ensuring sufficient power of the backup power supply. The specific solution is as follows:

[0005] A first aspect of the present application provides a backup power supply system for a wind turbine generator set, which is applied to the wind turbine generator set. The backup power supply system for the wind turbine generator set includes: an energy storage device, the energy storage device being connected to a self-powered device of the wind turbine generator set, the energy storage device being configured with a discharge mode and a charge mode, and the energy storage capacity of the energy storage device enabling the wind turbine generator set to achieve at least one black start;

[0006] When the power grid stops supplying power to the wind turbine generator set, the main control system of the wind turbine generator set controls the energy storage device to start and switch to the discharge mode to supply power to the self-use electrical equipment of the wind turbine generator set;

[0007] The main control system in the self-powered device sends a black start instruction to the converter of the wind turbine generator set and controls the path between the energy storage device and the converter. The energy storage device supplies power to the converter. The converter responds to the black start instruction, controls the output of the wind turbine generator set, and detects whether the output of the wind turbine generator set meets the preset grid connection conditions.

[0008] When the main control system receives information from the converter that the output of the wind turbine generator set meets the preset grid-connected conditions, the main control system controls the disconnection of the power supply connection between the energy storage device and the wind turbine generator set, controls the wind turbine generator set to enter a self-generated and self-used state, controls the passage between the energy storage device and the wind turbine generator set, and simultaneously switches the energy storage device to a charging mode, using the electricity generated by the wind turbine generator set to charge the energy storage device. The self-generated and self-used state is a state in which the wind turbine generator set operates normally and the electricity it generates drives the self-used electrical equipment to work.

[0009] In a possible implementation, the system further includes: an uninterruptible power supply connected to the gearbox lubrication pump of the wind turbine generator set, configured to supply power to the gearbox lubrication pump when power to the gearbox lubrication pump is disconnected.

[0010] In a possible implementation, the method further includes: a first circuit breaker;

[0011] Two ends of the first circuit breaker are connected to the output end of the energy storage device and the self-use electrical equipment respectively;

[0012] After the energy storage device is started and switched to the discharge mode, the first circuit breaker is closed to supply power to the self-powered device.

[0013] In a possible implementation, the device further includes: a self-use power transformer for converting the voltage of the energy storage device into a voltage level suitable for the wind turbine generator set, wherein the self-use power transformer includes: a tower base self-use power transformer deployed at the tower base of the wind turbine generator set, and a nacelle self-use power transformer deployed in the nacelle of the wind turbine generator set;

[0014] The low-voltage side of the tower base self-use transformer is connected to the energy storage device, and the high-voltage side of the tower base self-use transformer is connected to the high-voltage side of the cabin self-use transformer.

[0015] In a possible implementation, when the wind turbine generator set is a doubly-fed wind turbine generator set, the backup power supply system of the wind turbine generator set further includes: a series circuit consisting of a first soft-start resistor and a first soft-start contactor, and a second circuit breaker;

[0016] The two ends of the series circuit are respectively connected to the first end of the converter and the second circuit breaker, and the second end of the second circuit breaker is connected to the tower-based private power transformer of the private power equipment;

[0017] After the main control system sends the black start instruction to the converter, the main control system controls the second circuit breaker to close, and the converter controls the soft start contactor to close, so that the energy storage device is connected to the tower base self-use transformer through the converter to supply power to the converter.

[0018] In a possible implementation, the device further includes: a stator contactor and a third circuit breaker;

[0019] The first end of the stator contactor is connected to the stator of the doubly-fed wind turbine generator set, the second end of the stator contactor is connected to the first end of the third circuit breaker and the output end of the converter, and the second end of the third circuit breaker is connected to the first end of the second circuit breaker;

[0020] When the output of the wind turbine generator controlled by the converter satisfies a preset grid-connected condition, the converter controls the soft-start contactor and the second circuit breaker to be opened, thereby disconnecting the power supply connection between the energy storage device and the converter, and controls the stator contactor and the third circuit breaker to be closed, thereby starting modulation of the converter and causing the wind turbine generator set to enter a self-generated and self-used state;

[0021] The energy storage device is switched to a charging mode, and the second circuit breaker is controlled to be closed, so that the electricity generated by the wind turbine generator set is used to charge the energy storage device.

[0022] In a possible implementation, when the wind turbine generator set is a semi-vertical wind turbine generator set, the backup power supply system of the wind turbine generator set further includes: a second soft-start resistor, a fourth circuit breaker, and a grid-side circuit breaker;

[0023] The first end of the second soft-start resistor is connected to the converter, the second end of the second soft-start resistor is connected to the first end of the fourth circuit breaker, the second end of the fourth circuit breaker is connected to the tower base self-use transformer, and the first end of the grid-side circuit breaker is connected to the grid-side converter of the converter;

[0024] After the main control system sends the black start instruction to the converter, the main control system controls the fourth circuit breaker to close, so that the energy storage device is connected to the tower base self-use transformer through the converter to supply power to the converter. The converter establishes a DC bus voltage and closes the grid-side circuit breaker.

[0025] In a possible implementation, the device further includes: a machine-side circuit breaker and a fifth circuit breaker;

[0026] The first end of the generator-side circuit breaker is connected to the generator of the wind turbine generator set, and the second end of the generator-side circuit breaker is connected to the generator-side converter of the converter; the first end of the fifth circuit breaker is connected to the second end of the grid-side circuit breaker, and the second end of the fifth circuit breaker is connected to the second end of the fourth circuit breaker, and the fifth circuit breaker is connected in parallel with the fourth circuit breaker;

[0027] When the converter controls the output of the wind turbine generator to meet a preset grid-connected condition, the main control system controls the fourth circuit breaker to open, so as to disconnect the power supply connection between the energy storage device and the converter, and the generator-side converter controls the generator-side circuit breaker to close, so that the converter performs modulation, and the wind turbine generator set enters a self-generated and self-used state;

[0028] The energy storage device is switched to a charging mode, and the fifth circuit breaker is controlled to be closed, so that the electricity generated by the wind turbine generator set is used to charge the energy storage device.

[0029] In a possible implementation, the energy storage device uses a path to supply power to the converter, the converter controls the output of the wind turbine generator, and detects whether the output of the wind turbine generator meets a preset grid connection condition, including:

[0030] After the converter receives power from the energy storage device, the converter establishes a DC bus voltage.

[0031] The energy storage device provides power to the pitch control system of the wind turbine generator set;

[0032] The main control system controls the pitch system to open the pitches, so that the generator speed of the wind turbine generator set increases;

[0033] The main control system detects whether the generator speed reaches a preset grid-connected speed.

[0034] In a possible implementation, the method further includes:

[0035] When the main control system detects that the generator speed reaches the preset grid-connected speed, the converter excitation constructs the motor output of the wind turbine generator, and the motor output includes at least: voltage amplitude, frequency and phase;

[0036] The converter detects whether the motor output meets a preset grid-connected output condition.

[0037] A second aspect of the present application provides a wind turbine generator set, comprising the backup power supply system of the wind turbine generator set described in the first aspect or any implementation of the first aspect.

[0038] By means of the above technical solution, the present application uses an energy storage device as a backup power source for a wind turbine generator set. When the power grid does not supply power to the wind turbine generator set, the main control system controls the energy storage device to start and switch to a discharge mode to supply power to the self-use power equipment of the wind turbine generator set. Then, through the path between the energy storage device and the converter, power is supplied to the core power generation equipment of the wind turbine generator set, so that the wind turbine generator set starts to operate normally under the control of the converter and generates power. Since the energy storage capacity of the energy storage device can enable the wind turbine generator set to achieve at least one black start, it can ensure that the output of the wind turbine generator reaches the preset grid connection condition. After the output of the self-use power equipment reaches the preset grid connection condition, it proves that the power generation output of the wind turbine generator set can achieve self-generation and self-use, completing the black start of the wind turbine generator, and then disconnecting the power supply connection between the energy storage device and the wind turbine generator set, and disconnecting the power supply of the energy storage device. At the same time, after the energy storage device is switched to a charging mode, the connection between the energy storage device and the wind turbine generator set is reconnected, and the power generated by the wind turbine generator set can use this path to charge the energy storage device.

[0039] The energy storage device of the present application switches modes and controls the path connection with the converter before switching between different modes. This allows the power generated by the wind turbine to be used to store energy for the next black start after completing one black start, avoiding the problem of insufficient backup power causing black start interruption, realizing the recycling of the energy storage device and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The above and other features, advantages, and aspects of the various embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and that the originals and elements are not necessarily drawn to scale.

[0041] Figure 1 An optional system architecture diagram of a backup power supply system for a wind turbine generator set provided in an embodiment of the present application;

[0042] Figure 2 A schematic diagram of an optional process for implementing a black start of a wind turbine generator system provided in an embodiment of the present application;

[0043] Figure 3 An optional system architecture diagram of a backup power supply system for a semi-direct-drive wind turbine generator set provided in an embodiment of the present application;

[0044] Figure 4 An optional system architecture diagram of a backup power supply system for a doubly-fed wind turbine generator set provided in an embodiment of the present application. DETAILED DESCRIPTION

[0045] The following describes the embodiments of the present application in conjunction with the accompanying drawings. The terms used in the implementation methods of the present application are only used to explain the specific embodiments of the present application and are not intended to limit the present application.

[0046] The embodiments of the present application are described below in conjunction with the accompanying drawings. Those skilled in the art will appreciate that, with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0047] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, and this is merely a way of distinguishing the objects of the same attributes when describing them in the embodiments of the present application. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, so that the process, method, system, product or equipment comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0048] This application can be applied to the fields of wind turbines, backup power supplies, and black starts. A black start of a wind turbine refers to the ability to start and operate a wind turbine through its own control without relying on the assistance of other network devices after the system loses power due to a fault. The following uses the backup power supply of a wind turbine as an example to introduce multiple application scenarios implemented in the product.

[0049] First, an optional application scenario of the present application is introduced. Wind farms deployed in typhoon or turbulent areas, due to their special geographical location, cannot be restored in time once the power grid is cut off. In addition, during the period when the power is not on and the power grid is cut off, the wind position of the wind turbine generator set (hereinafter referred to as the wind turbine generator set) has an important impact on the load size of the unit. Especially under the structural characteristics of high power and long blades of wind turbines, it is often necessary to control pitch and yaw. Long-term power outages will cause the blades to be unable to adjust their angles according to changes in wind speed. The unit will deviate from the optimal wind angle, which may cause uneven force on the unit structure and increase the risk of fatigue damage to components such as the tower and foundation.

[0050] Existing technology equips wind turbines with backup power sources, such as diesel generators, to ensure they can be black-started in the event of a main power outage. However, diesel generators, which rely on fuel as their energy source, are essential for black starting. Once the diesel generator runs out of fuel, the wind turbine loses its backup power source and can only operate for a limited period, resulting in a black-start interruption.

[0051] In order to solve the above problems, the embodiment of the present application provides a backup power supply system for a wind turbine generator set and a wind turbine generator set. The backup power supply system for a wind turbine generator set and a wind turbine generator set according to the embodiment of the present application are described in detail below with reference to the accompanying drawings.

[0052] Reference Figure 1 , Figure 1 An optional system architecture diagram of the backup power supply system of the wind turbine generator set provided in the embodiment of the present application is as follows: Figure 1 As shown, the system architecture includes: a wind turbine generator set, a power grid, and a backup power supply system for the wind turbine generator set, wherein the wind turbine generator set includes at least: self-powered equipment and a converter, and the self-powered equipment includes at least: blades, a generator, a pitch control system, a gearbox lubrication pump, and a main control system. An embodiment of the present application provides a backup power supply system for a wind turbine generator set, including: an energy storage device, the energy storage device is connected to the self-powered equipment of the wind turbine generator set, the energy storage device is configured with a discharge mode and a charge mode, and the energy storage capacity of the energy storage device enables the wind turbine generator set to achieve at least one black start.

[0053] The energy storage device refers to a device or system that can store energy in the form of electrical energy, thermal energy, mechanical energy, etc., and release it when needed. In the embodiment of the present application, the energy storage device can be a device with a voltage level of AC 400V and is used to store electrical energy. The stored electrical energy can support at least one black start of the wind turbine. In discharge mode, the energy storage device releases the stored electrical energy to support the wind turbine to achieve a black start. After the black start is completed, that is, the wind turbine achieves self-generation and self-use, the energy storage device switches to charging mode and uses the power generated by the wind turbine to charge, storing energy for the next black start.

[0054] Reference Figure 2 , an optional flow chart of realizing the black start of a wind turbine generator set provided in an embodiment of the present application, describes in detail the process of realizing the black start of a wind turbine generator set using the above structure.

[0055] Step S110: When the power grid stops supplying power to the wind turbine generator set, the main control system controls the energy storage device to start and switch to the discharge mode to supply power to the self-use electrical equipment of the wind turbine generator set.

[0056] There are two general scenarios where a wind turbine may be disconnected from power: when the wind turbine is initially established and has not yet established a power connection with the grid; and when the grid is in the process of supplying power to the wind turbine and power is interrupted due to a fault, weather, or other reasons. In both of these situations, upon detecting a power outage, the main control system sends a discharge mode power supply command to the backup power source, the energy storage device, causing it to start and switch to discharge mode, releasing energy to power the wind turbine's own electrical equipment. Furthermore, the control system monitors and controls the discharge and charging modes of the energy storage device, records and stores the energy storage device's status, and issues alarms when entering and exiting a black start.

[0057] Among them, the self-powered equipment of wind turbines refers to the equipment for the normal operation, monitoring, maintenance and safety of the units, such as pitch systems, communication equipment, sensors (wind speed / wind direction / temperature), etc. These devices are usually not directly involved in power generation, but are crucial to the operation, reliability and efficiency of wind turbines. They can subsequently support the main control system and converter to achieve black start of wind turbines.

[0058] In step S120, the main control system sends a black start instruction to the converter of the wind turbine generator set and controls the path between the energy storage device and the converter. The energy storage device supplies power to the converter. The converter responds to the black start instruction and controls the output of the wind turbine generator set.

[0059] The main control system sends a black start command to the converter. At the same time, the main control system controls the contactors, circuit breakers and other components between the energy storage device and the wind turbine generator set to realize the connection between the energy storage device and the wind turbine generator set. Using this connection, the energy storage device supplies power to the unit's own electrical equipment, such as the gear box lubrication pump, pitch control system, etc., so that the wind turbine generator set can gradually return to normal power generation state.

[0060] It is understood that when the wind turbine's power generation reaches a state of self-consumption, the energy generated by the self-use equipment is sufficient to support the unit's own operation, the black start is complete, and the energy storage device can stop supplying power to the converter. Therefore, after supplying power to the converter, the converter responds to the black start instruction, controls the output of the self-use equipment, and detects whether the output of the self-use equipment meets the preset grid connection conditions. The preset grid connection conditions are that the output of the self-use equipment reaches a state of self-consumption, such as when the wind turbine's generator speed reaches a preset speed.

[0061] Step S130 , detecting whether the output of the wind turbine generator meets the preset grid connection condition. If so, executing step S140 ; ​​if not, continuing the detection.

[0062] In step S140, the main control system controls the disconnection of the power supply connection between the energy storage device and the wind turbine generator set, and controls the wind turbine generator set to enter a self-generation and self-use state, in which the wind turbine generator set can maintain normal operation and the power it generates drives its own electrical equipment to work.

[0063] It is understandable that when the power generation state of the wind turbine can reach the point where it is sufficient for self-use to support the operation of the turbine itself, the black start is completed and the energy storage device can stop supplying power to the wind turbine.

[0064] Step S150 , switching the energy storage device to a charging mode, controlling the connection between the energy storage device and the wind turbine generator set, and using the electricity generated by the wind turbine generator set to charge the energy storage device.

[0065] The converter monitors the generator's output in real time. When the generator's output meets the preset grid-connection conditions, the converter feeds back information to the control system. Based on this feedback, the main control system disconnects the wind turbine from the energy storage device, allowing the wind turbine to operate in a self-built grid for self-generation and self-consumption. The self-generation and self-consumption state of a wind turbine can be understood as the operating state in which the wind turbine, disconnected from the external grid, independently supplies power to local loads through its own power generation equipment.

[0066] Among them, disconnecting the power supply connection between the wind turbine and the energy storage device can be understood as disconnecting the power supply connection between the energy storage device and the self-use power equipment and the converter. On this basis, the energy storage device is switched to charging mode and no longer supplies power to the self-use power equipment of the wind turbine. The power generated by the wind turbine is used to charge the energy storage device, and energy is stored for the next black start of the wind turbine, thereby realizing the recycling of the backup power supply. Compared with the existing technology of using batteries and diesel engines as backup power sources, on the one hand, the wind turbine always has a backup power supply sufficient to achieve black start, and supplies power in time at the moment of power outage, avoiding the problem of long-term power outage of the unit due to insufficient battery power or diesel engine fuel, and reducing the impact of power outages on wind turbine equipment. On the other hand, the backup power supply can use the wind turbine to generate electricity and charge energy, so that the energy storage device can be recycled, reducing energy consumption while saving the workload of staff adding fuel.

[0067] In summary, the present application uses an energy storage device as a backup power source for a wind turbine generator set. When the power grid does not supply power to the wind turbine generator set, the main control system controls the energy storage device to start and switch to a discharge mode to supply power to the wind turbine generator set's own electrical equipment. Afterwards, the power supply to the wind turbine generator set's own electrical equipment is realized through the path between the energy storage device and the wind turbine generator set, so that the wind turbine generator set starts to operate normally under the control of the main control system and the converter to generate electricity. Since the energy storage capacity of the energy storage device can enable the wind turbine generator set to achieve at least one black start, it can ensure that the output of the wind turbine generator reaches the preset grid-connected condition. After the output of the generator reaches the preset grid-connected condition, it proves that the power generation output of the wind turbine generator set can achieve self-generation and self-use, completing the black start of the wind turbine generator, and then disconnecting the power supply connection between the energy storage device and the wind turbine generator set, disconnecting the power supply of the energy storage device. At the same time, after the energy storage device is switched to a charging mode, the connection between the energy storage device and the wind turbine generator set is reconnected, and the power generated by the wind turbine generator set can use this path to charge the energy storage device.

[0068] The energy storage device of the present application switches modes and controls the path connection with the converter before switching between different modes. This allows the power generated by the wind turbine to be used to store energy for the next black start after completing one black start, avoiding the problem of insufficient backup power causing black start interruption, realizing the recycling of the energy storage device and reducing energy consumption.

[0069] Next, other possible implementations of the backup power supply system for the wind turbine generator set provided by the present application will be described in detail through the following embodiments.

[0070] In a possible implementation, the backup power supply system of the wind turbine generator set further includes: an uninterruptible power supply connected to the gearbox lubrication pump of the wind turbine generator set, configured to supply power to the gearbox lubrication pump when power to the gearbox lubrication pump is disconnected.

[0071] Understandably, during a wind turbine black start, the backup power supply must be disconnected before switching to wind turbine power. During this switchover, various components within the turbine are de-energized, including the gearbox lubrication pump. The high-speed gears, bearings, and other moving parts within the wind turbine's gearbox generate significant friction and heat during operation. The gearbox lubrication pump is responsible for pumping lubricating oil from the oil tank and delivering it through oil pipes at a specific pressure and flow rate to the key areas within the gearbox that require lubrication. This provides forced lubrication, ensuring that even at high speeds, heavy loads, or in specific operating conditions, lubricating oil is accurately, stably, and continuously delivered to the friction surfaces, forming an effective lubricating film to prevent dry friction and excessive wear. However, during the switching interval, the gearbox lubrication pump briefly loses power, which can impact the entire lifecycle of the gearbox bearings, especially the sliding bearing gearbox.

[0072] Therefore, in the embodiment of the present application, the backup power supply system of the wind turbine generator set is equipped with an uninterruptible power supply for the gear box lubrication pump. Figure 1 The first end of the uninterruptible power supply (UPS) is connected to the gearbox lubrication pump, and the second end is connected to the grid and the backup power source (energy storage device). When the grid or backup power source is providing power, the UPS bypasses the system and directly supplies power to the gearbox lubrication pump. The UPS can be continuously charged using the grid or backup power source to maintain a full charge, ensuring that the gear lubrication pump can be immediately powered in the event of a grid or backup power outage. Optionally, a 400V UPS suitable for the nacelle voltage level can be used to power the gearbox lubrication pump when the power connection between the energy storage device and the wind turbine is disconnected, and when the wind turbine is operating in a self-generated and self-sustaining state.

[0073] Optionally, the UPS can power the unit's gearbox lubrication pump throughout its lifecycle. For example, it provides power between the time the unit is disconnected from power or the grid loses power and the time the energy storage device starts up. If a power outage is detected, the pump is immediately reenergized to ensure adequate lubrication of the gearbox bearings and reduce wear. Furthermore, to minimize UPS capacity requirements, the gearbox lubrication pump operates at a low speed during a black start, extending the UPS's service life.

[0074] In one possible implementation, when the wind turbine generator set is a doubly-fed wind turbine generator set, the backup power supply system of the wind turbine generator set also includes: a first circuit breaker; the two ends of the first circuit breaker are respectively connected to the output end of the energy storage device and the self-power device; after the energy storage device is started and switched to the discharge mode, the first circuit breaker is closed to supply power to the self-power device.

[0075] As can be understood, a first circuit breaker is provided at the output end of the energy storage device to control the connection and disconnection between the backup power supply and the wind turbine, thereby meeting the wind turbine's demand for backup power and its charging needs in different situations. For example, when the wind turbine is generating electricity to charge the backup power supply, the first circuit breaker can be controlled to open for a short period of time after the backup power supply is fully charged. In the event of a power outage in the wind turbine, the first circuit breaker is controlled to close, connecting the energy storage device to the wind turbine's own power equipment, allowing the energy storage device to supply power to the wind turbine.

[0076] Reference Figure 3, an optional system architecture diagram of a backup power supply system for a semi-direct-drive wind turbine generator set provided in an embodiment of the present application, wherein the two ends of a first circuit breaker Q5 are respectively connected to a backup power supply (energy storage device) and a self-powered device of the semi-direct-drive wind turbine generator set. When the semi-direct-drive wind turbine generator set suddenly loses power, the backup power supply starts to switch to a discharge mode, and then controls the first circuit breaker Q5 to close, so that the backup power supply is connected to the self-powered device and power is supplied to the self-powered device.

[0077] Reference Figure 4 , an optional system architecture diagram of a backup power supply system for a doubly-fed wind turbine generator set provided in an embodiment of the present application, wherein the two ends of a first circuit breaker Q3 are connected to a backup power supply (energy storage device) and a self-powered device of the doubly-fed wind turbine generator set, respectively. When the doubly-fed wind turbine generator set suddenly loses power, the backup power supply starts to switch to a discharge mode, and then controls the first circuit breaker Q3 to close, connecting the backup power supply to the self-powered device and supplying power to the self-powered device.

[0078] It is understandable that Figure 3 、 Figure 4 In the backup power supply system of the semi-direct-drive wind turbine generator set and the backup power supply system of the doubly-fed wind turbine generator set shown, when the wind turbine generator set is not powered on or the grid is powered off, the contactors, circuit breakers, etc. in the system are in the disconnected state. The above-mentioned closing and disconnecting control operations are all achieved on this basis.

[0079] In one possible implementation, the backup power supply system of the wind turbine generator set further includes: a self-use power transformer for converting the voltage of the energy storage device into a voltage level suitable for the wind turbine generator set, the self-use power transformer including: a tower-based self-use power transformer deployed at the tower base of the wind turbine generator set, and a cabin self-use power transformer deployed in the cabin of the wind turbine generator set; the low-voltage side of the tower-based self-use power transformer is connected to the energy storage device, and the high-voltage side of the tower-based self-use power transformer is connected to the high-voltage side of the cabin self-use power transformer.

[0080] It is understandable that the main circuit system of modern large-scale wind turbines, and the common operating voltage on the wind turbine grid side, is 1140VAC (50Hz / 60Hz). However, the backup power supply used in this application is a 400V-level energy storage device. If the 400V low-voltage backup power supply is connected to a device requiring a higher voltage, the wind turbine will not be able to start or operate, and a black start will not be completed.

[0081] Therefore, in the embodiments of the present application, a self-use transformer is used in the backup power system to convert the low-level voltage of the energy storage device into a voltage suitable for the wind turbine equipment, thereby achieving a black start. Optionally, the self-use transformers of the present application are arranged in a distributed manner, with the self-use transformers placed at the tower base and the nacelle, converting the supply voltage of the energy storage device into a voltage suitable for the tower base distribution equipment and a voltage suitable for the nacelle distribution equipment, respectively.

[0082] Reference Figure 3 and Figure 4 After the first circuit breaker of the 400VC backup power supply (energy storage device) closes, power is supplied to the tower base's power transformer (1140V / 400V), which in turn supplies power to the nacelle's power transformer (1140V / 400V). This energizes all of the wind turbine's power equipment (such as the pitch control system, gearbox lubrication pump, and main control system shown in the figure). The main control system comprehensively monitors the wind turbine's overall status. The nacelle's power transformer uses an 1140V primary voltage, which offers greater cost advantages compared to a 400V primary voltage, reducing investment and being closer to the load center, resulting in less voltage drop.

[0083] In one possible implementation, when the wind turbine generator set is a doubly-fed wind turbine generator set, the backup power supply system of the wind turbine generator set also includes: a series circuit consisting of a first soft-start resistor and a first soft-start contactor, and a second circuit breaker; the two ends of the series circuit are respectively connected to the first end of the converter and the second circuit breaker, and the second end of the second circuit breaker is connected to the tower-based self-use transformer of the self-use electrical equipment; after the main control system sends a black start instruction to the converter, the main control system controls the second circuit breaker to close, and the converter controls the soft-start contactor to close, so that the energy storage device is connected to the tower-based self-use transformer through the converter to supply power to the converter.

[0084] Reference Figure 4 The first soft-start resistor and the first soft-start contactor KM2 are connected in series. One end of the series circuit is connected to the converter, and one end is connected to the first end of the second circuit breaker Q2. The second end of the second circuit breaker Q2 is connected to the tower-based self-service transformer. It will be appreciated that the tower-based self-service transformer is used to convert the voltage provided by the energy storage device into a voltage suitable for the converter. Therefore, if the backup power supply can directly provide a voltage suitable for the converter, the second end of the second circuit breaker Q2 can be directly connected to the backup power supply.

[0085] After the energy storage device supplies power to the self-powered equipment and the main control system, it activates the control and monitoring system for black start. Furthermore, the main control system sends a black start instruction to the converter and controls the first soft-start contactor KM2 and the second circuit breaker Q2 in the series circuit to close, thus realizing the power supply path between the energy storage device and the converter. The energy storage device supplies power to the converter, and after the converter is energized, the DC bus voltage is established.

[0086] The DC bus voltage is the voltage of the DC link inside the converter. The converter converts the AC input voltage provided by the backup power supply into DC voltage through a rectifier circuit, smoothes the fluctuations through capacitor filtering, and stores energy on the DC bus to maintain voltage stability, serving as an "energy pool" for subsequent inversion or energy conversion.

[0087] In the above process, the DC bus of the converter is usually connected to a large-capacity capacitor. At the moment the energy storage device is connected, the capacitor is equivalent to a short circuit, resulting in a very large instantaneous charging current. The soft-start resistor is connected in series with the input end of the converter. Through resistor voltage division and current limiting, the extremely large instantaneous current is limited to a safe range, reducing the impact of the extremely large instantaneous current on the entire backup power supply system and improving the safety and reliability of the backup power supply system.

[0088] In one possible implementation, when the wind turbine generator set is a doubly-fed wind turbine generator set, the backup power supply system of the wind turbine generator set also includes: a stator contactor and a third circuit breaker; the first end of the stator contactor is connected to the stator of the doubly-fed wind turbine generator set, the second end of the stator contactor is connected to the first end of the third circuit breaker and the output end of the converter, and the second end of the third circuit breaker is connected to the first end of the second circuit breaker; when the converter controls the output of the wind turbine generator to meet the preset grid-connected conditions, the converter controls the soft-start contactor and the second circuit breaker to be disconnected to disconnect the power supply connection between the energy storage device and the converter, and controls the stator contactor and the third circuit breaker to be closed, starts the modulation of the converter, and puts the wind turbine generator set into a self-built grid state; switches the energy storage device to a charging mode, controls the second circuit breaker to be closed, and allows the power generated by the wind turbine generator set to charge the energy storage device.

[0089] Reference Figure 4 The stator contactor KM1 and the third circuit breaker Q1 are connected in series with the generator. The first end of the stator contactor KM1 is connected to the output of the doubly-fed wind turbine's converter, and the second end of the third circuit breaker Q1 is connected to the second circuit breaker Q2. This connection allows the power generated by the generator of the doubly-fed wind turbine to be supplied to the converter through the connection between the grid-side converter and the generator, maintaining converter control of the wind turbine's output. Self-use equipment can receive power from the generator of the doubly-fed wind turbine via the circuits KM1, Q1, and Q2.

[0090] However, if the energy storage device is in discharge mode and the generator can also power the entire wind turbine, if KM1, Q1, and Q2 are closed simultaneously, the turbine generator power supply and the backup power supply will be connected in parallel, causing the turbine to malfunction. Therefore, in this embodiment of the application, the second circuit breaker Q2 is interlocked with the stator contactor KM1 and the third circuit breaker Q1. That is, when the backup power supply is in discharge mode, Q2 and Q1 are prohibited from being closed simultaneously; when the backup power supply is in charging mode, Q2, KM1, and Q1 can be closed simultaneously.

[0091] Based on this, a black start is jointly implemented by the main control system and the converter. In a doubly-fed wind turbine, after the wind turbine receives power from the energy storage device and the converter, the main control system controls the variable pitch system to open the blades, increasing the generator speed of the wind turbine. The converter detects the generator speed and feeds it back to the main control system, allowing it to determine whether it has reached the preset grid-connected speed. When it detects that the generator speed has reached the preset grid-connected speed, the converter excites the wind turbine motor to generate the motor output, which includes at least the amplitude, frequency, and phase of the stator voltage. The converter then detects whether the motor output meets the preset grid-connected output conditions.

[0092] After the main control system sends a black start command to the converter, it sends a pitch-open command to the pitch control system. The pitch control system responds to the pitch-open command to rotate the blades of the doubly-fed wind turbine. Consequently, the generator speed increases until it reaches the preset grid-connected speed. Grid-connected means directly connected to the public grid, and the preset grid-connected speed here refers to the generator speed at which the wind turbine generates electricity.

[0093] When the output of the DFIG reaches the preset grid-connection conditions, indicating that the DFIG is generating sufficient electricity for self-use, the converter can be disconnected from the backup power source by disconnecting KM2 and Q2. Furthermore, the converter controls the closing of stator contactor KM1 and third circuit breaker Q1. Simultaneous closing of second circuit breaker Q2 and first circuit breaker Q3 is prohibited, so second circuit breaker Q2 remains open. The grid-side converter then begins modulation. Energy from the generator's stator continues to excite the generator through the converter, maintaining stable stator voltage amplitude, frequency, and phase. The DFIG enters grid-building mode.

[0094] During this process, the converter and main control system monitor the status of all components throughout the system. When the output of all components of the doubly-fed wind turbine meets the preset grid-connection conditions, the black start is complete and the entire system enters the self-built grid state. For example, if the wind turbine's motor output reaches a preset threshold and remains stable, it can be determined that the doubly-fed wind turbine's output meets the preset grid-connection conditions. Motor output includes at least the amplitude, frequency, and phase of the stator voltage.

[0095] Furthermore, the power supply for the DFIG wind turbine's self-use equipment needs to be switched from the backup power source to the generator, necessitating the reclosing of the second circuit breaker, Q2. First, the backup power source, or energy storage device, is switched to charging mode. In this state, KM1, Q1, and Q2 can be closed simultaneously, preventing the dual power sources from being connected in parallel. Consequently, the DFIG wind turbine enters a self-use mode. Furthermore, since the backup power source can also receive power from the DFIG wind turbine via the same path as KM1, Q1, and Q2, charging of the energy storage device is achieved.

[0096] In another possible implementation, when the wind turbine generator set is a semi-DC wind turbine generator set, the backup power supply system of the wind turbine generator set also includes: a second soft-start resistor, a fourth circuit breaker and a grid-side circuit breaker; the first end of the second soft-start resistor is connected to the converter, the second end of the second soft-start resistor is connected to the first end of the fourth circuit breaker, the second end of the fourth circuit breaker is connected to the tower base self-use transformer, and the first end of the grid-side circuit breaker is connected to the grid-side converter of the converter; after the main control system sends a black start instruction to the converter, the main control system controls the fourth circuit breaker to close, so that the energy storage device is connected to the tower base self-use transformer through the converter, and supplies power to the converter, the converter establishes a DC bus voltage, and closes the grid-side circuit breaker.

[0097] Reference Figure 3 A second soft-start resistor and a fourth circuit breaker Q3 are set on the power supply path between the backup power supply and the converter. The main control system sends a black start command to the converter and controls the closing of the fourth circuit breaker Q3 to realize the power supply path between the backup power supply and the converter. The backup power supply uses this path to supply power to the converter, and the converter establishes the DC bus voltage. After the soft start is completed, the grid-side circuit breaker Q2 of the converter is closed, and the impact on the backup power supply system is reduced by the soft-start resistor.

[0098] Based on this, the black start is jointly implemented by the main control system and the converter. In the semi-direct-drive wind turbine set, after the converter receives power from the energy storage device, the converter establishes the DC bus voltage, and the main control system controls the variable pitch system to open the pitch, so that the generator speed of the semi-direct-drive wind turbine set increases; and the converter detects whether the generator speed reaches the preset grid-connected speed.

[0099] After the main control system sends a black start command to the converter, it sends a pitch-open command to the pitch control system. The pitch control system responds to the pitch-open command to rotate the blades of the semi-direct-drive wind turbine. Consequently, the generator speed increases until it reaches the preset grid-connected speed. Grid-connected means directly connected to the public grid, and the preset grid-connected speed here refers to the speed at which the wind turbine generator reaches its target when generating electricity.

[0100] In one possible implementation, when the wind turbine generator set is a semi-direct wind turbine generator set, the backup power supply system of the wind turbine generator set further includes: a machine-side circuit breaker and a fifth circuit breaker; the first end of the machine-side circuit breaker is connected to the generator of the wind turbine generator set, and the second end of the machine-side circuit breaker is connected to the machine-side converter of the converter; the first end of the fifth circuit breaker is connected to the second end of the grid-side circuit breaker, the second end of the fifth circuit breaker is connected to the second end of the fourth circuit breaker, and the fifth circuit breaker is connected in parallel with the fourth circuit breaker; when the converter controls the output of the wind turbine generator to meet the preset grid-connected conditions, the main control system controls the fourth circuit breaker to disconnect to disconnect the power supply connection between the energy storage device and the converter, the machine-side converter controls the machine-side circuit breaker to close, so that the converter is modulated, and the wind turbine generator set enters a self-generated and self-used state; the energy storage device is switched to a charging mode, and the fifth circuit breaker is controlled to close so that the power generated by the wind turbine generator set is used to charge the energy storage device.

[0101] Reference Figure 3 The two ends of the generator-side circuit breaker Q1 are connected to the generator and the generator-side converter of the semi-direct-drive wind turbine generator set, respectively. When the main control system detects that the generator speed has reached the preset grid-connected speed, the main control system controls the opening of the fourth circuit breaker Q3, and the converter controls the closing of the generator-side circuit breaker Q1. Simultaneously, the main control system sends a power generation command to the converter, switching the converter's power supply from the backup power source to the generator of the semi-direct-drive wind turbine set, and the semi-direct-drive wind turbine set enters the self-generation and self-consumption mode. During this process, the main control system and the converter jointly monitor the overall status of the semi-direct-drive wind turbine set. When the overall status reaches the self-use grid state, the semi-direct-drive wind turbine set has achieved self-generation and self-consumption capabilities. At this point, the fifth circuit breaker Q4 can be closed, and the semi-direct-drive wind turbine set generates electricity to power its own electrical equipment.

[0102] However, if the energy storage device is in discharge mode and the generator can also power the entire wind turbine, if the fifth circuit breaker Q4 and the first circuit breaker Q5 are closed simultaneously, the turbine generator power supply and the backup power supply will be connected in parallel, causing the turbine to malfunction. Therefore, in the embodiment of the present application, the fifth circuit breaker Q4 and the first circuit breaker Q5 are designed with software and hardware interlocks. When the backup power supply is in discharge mode, the fifth circuit breaker Q4 and the first circuit breaker Q5 are prohibited from being closed simultaneously; when the backup power supply is in charging mode, the fifth circuit breaker Q4 and the first circuit breaker Q5 can be closed simultaneously.

[0103] Therefore, before closing the fifth circuit breaker Q4, the energy storage device is first switched to charging mode. Then, the fifth circuit breaker Q4 is closed, allowing the semi-direct-drive wind turbine to generate electricity and power the self-use equipment. Simultaneously, the energy storage device can also be charged. In another possible implementation, before closing the fifth circuit breaker Q4, the first circuit breaker Q5 is opened to stop the energy storage device from supplying power. Then, the fifth circuit breaker Q4 is closed, allowing the semi-direct-drive wind turbine to generate electricity and power the self-use equipment. If the energy storage device needs to be charged, the energy storage device is switched to charging mode and the first circuit breaker Q5 is closed to enable charging.

[0104] In summary, the embodiment of the present application designs a backup power supply system for a wind turbine, in which an energy storage device is used as a backup power supply for the wind turbine, and the main control system starts the backup power supply to supply power to the unit's self-use electrical equipment and converter, and controls the wind turbine's variable pitch system, generator, etc. to meet the grid connection conditions. After the grid connection conditions are met, the control system cuts off the energy storage device and switches to the wind turbine to supply power to the self-use electrical equipment, and the wind turbine enters a state of complete self-generation and self-use. On this basis, the energy storage device is switched to charging mode and connected to the wind turbine again, and the wind turbine charges the energy storage device to store energy for the next black start, ensuring that there is enough power to achieve a black start. Therefore, the wind turbine can continue to operate throughout its entire life cycle before power is supplied and during power outages, ensuring that the unit can change pitch and yaw in an emergency, and ensuring the safety of the unit.

[0105] This backup power system is suitable for semi-direct-drive and doubly-fed wind turbines. It supports black starts, enabling the turbine to operate independently and charge the backup power supply, ensuring uninterrupted operation before power is restored and during grid outages. Optionally, after achieving self-consumption, the system can also provide power to other nearby wind turbines via collector lines, acting as a backup power source for other outages and ensuring safe operation of the entire wind farm.

[0106] In addition, this application also designs an uninterruptible power supply UPS for the gearbox lubrication pump, a key component. During the power switching gap when the wind turbine grid suddenly loses power and the unit is black-started, the gearbox lubrication pump is powered so that the gearbox bearings can be fully lubricated, thereby improving the life and reliability of the gearbox.

Claims

1. A backup power supply system for a wind turbine generator set, characterized in that: Applied to a wind turbine generator set, the backup power supply system of the wind turbine generator set includes: an energy storage device, the energy storage device is connected to the self-powered equipment of the wind turbine generator set, the energy storage device is configured with a discharge mode and a charge mode, and the energy storage capacity of the energy storage device enables the wind turbine generator set to achieve at least one black start; When the power grid stops supplying power to the wind turbine generator set, the main control system of the wind turbine generator set controls the energy storage device to start and switch to the discharge mode to supply power to the self-use electrical equipment of the wind turbine generator set; The main control system in the self-powered device sends a black start instruction to the converter of the wind turbine generator set and controls the path between the energy storage device and the converter. The energy storage device supplies power to the converter. The converter responds to the black start instruction, controls the output of the wind turbine generator set, and detects whether the output of the wind turbine generator set meets the preset grid connection conditions. When the main control system receives information from the converter that the output of the wind turbine generator set meets the preset grid-connected conditions, the main control system controls the disconnection of the power supply connection between the energy storage device and the wind turbine generator set, controls the wind turbine generator set to enter a self-generated and self-used state, controls the passage between the energy storage device and the wind turbine generator set, and simultaneously switches the energy storage device to a charging mode, using the electricity generated by the wind turbine generator set to charge the energy storage device. The self-generated and self-used state is a state in which the wind turbine generator set operates normally and the electricity it generates drives the self-used electrical equipment to work.

2. The backup power supply system of a wind turbine generator set according to claim 1, characterized in that: Also includes: An uninterruptible power supply connected to the gearbox lubrication pump of the wind turbine generator set is used to supply power to the gearbox lubrication pump when the power supply to the gearbox lubrication pump is disconnected.

3. The backup power supply system of a wind turbine generator set according to claim 1, characterized in that: Also includes: First circuit breaker; Two ends of the first circuit breaker are connected to the output end of the energy storage device and the self-use electrical equipment respectively; After the energy storage device is started and switched to the discharge mode, the first circuit breaker is closed to supply power to the self-powered device.

4. The backup power supply system for a wind turbine generator set according to claim 3, characterized in that: Also includes: A self-use power transformer for converting the voltage of the energy storage device into a voltage level suitable for the wind turbine generator set, wherein the self-use power transformer comprises: a tower base self-use power transformer deployed at the tower base of the wind turbine generator set, and a nacelle self-use power transformer deployed at the nacelle of the wind turbine generator set; The low-voltage side of the tower base self-use transformer is connected to the energy storage device, and the high-voltage side of the tower base self-use transformer is connected to the high-voltage side of the cabin self-use transformer.

5. The backup power supply system for a wind turbine generator set according to any one of claims 1 to 4, characterized in that: In the case where the wind turbine generator set is a doubly-fed wind turbine generator set, the backup power supply system of the wind turbine generator set further comprises: a series circuit consisting of a first soft-start resistor and a first soft-start contactor, and a second circuit breaker; The two ends of the series circuit are respectively connected to the first end of the converter and the second circuit breaker, and the second end of the second circuit breaker is connected to the tower-based private power transformer of the private power equipment; After the main control system sends the black start instruction to the converter, the main control system controls the second circuit breaker to close, and the converter controls the soft start contactor to close, so that the energy storage device is connected to the tower base self-use transformer through the converter to supply power to the converter.

6. The backup power supply system for a wind turbine generator set according to claim 5, characterized in that: Also includes: stator contactor and third circuit breaker; The first end of the stator contactor is connected to the stator of the doubly-fed wind turbine generator set, the second end of the stator contactor is connected to the first end of the third circuit breaker and the output end of the converter, and the second end of the third circuit breaker is connected to the first end of the second circuit breaker; When the output of the wind turbine generator controlled by the converter satisfies a preset grid-connected condition, the converter controls the soft-start contactor and the second circuit breaker to be opened, thereby disconnecting the power supply connection between the energy storage device and the converter, and controls the stator contactor and the third circuit breaker to be closed, thereby starting modulation of the converter and causing the wind turbine generator set to enter a self-generated and self-used state; The energy storage device is switched to a charging mode, and the second circuit breaker is controlled to be closed, so that the electricity generated by the wind turbine generator set is used to charge the energy storage device.

7. The backup power supply system for a wind turbine generator set according to any one of claims 1 to 4, characterized in that: In the case where the wind turbine generator set is a semi-direct wind turbine generator set, the backup power supply system of the wind turbine generator set further comprises: a second soft-start resistor, a fourth circuit breaker and a grid-side circuit breaker; The first end of the second soft-start resistor is connected to the converter, the second end of the second soft-start resistor is connected to the first end of the fourth circuit breaker, the second end of the fourth circuit breaker is connected to the tower base self-use transformer, and the first end of the grid-side circuit breaker is connected to the grid-side converter of the converter; After the main control system sends the black start instruction to the converter, the main control system controls the fourth circuit breaker to close, so that the energy storage device is connected to the tower base self-use transformer through the converter to supply power to the converter. The converter establishes a DC bus voltage and closes the grid-side circuit breaker.

8. The backup power supply system for a wind turbine generator set according to claim 7, characterized in that: Also includes: Generator-side circuit breaker and fifth circuit breaker; The first end of the generator-side circuit breaker is connected to the generator of the wind turbine generator set, and the second end of the generator-side circuit breaker is connected to the generator-side converter of the converter; the first end of the fifth circuit breaker is connected to the second end of the grid-side circuit breaker, and the second end of the fifth circuit breaker is connected to the second end of the fourth circuit breaker, and the fifth circuit breaker is connected in parallel with the fourth circuit breaker; When the converter controls the output of the wind turbine generator to meet a preset grid-connected condition, the main control system controls the fourth circuit breaker to open, so as to disconnect the power supply connection between the energy storage device and the converter, and the generator-side converter controls the generator-side circuit breaker to close, so that the converter performs modulation, and the wind turbine generator set enters a self-generated and self-used state; The energy storage device is switched to a charging mode, and the fifth circuit breaker is controlled to be closed, so that the electricity generated by the wind turbine generator set is used to charge the energy storage device.

9. The backup power supply system for a wind turbine generator set according to claim 1, characterized in that: The energy storage device supplies power to the converter via a path, and the converter controls the output of the wind turbine generator and detects whether the output of the wind turbine generator meets a preset grid connection condition, including: After the converter receives power from the energy storage device, the converter establishes a DC bus voltage. The energy storage device provides power to the pitch control system of the wind turbine generator set; The main control system controls the pitch system to open the pitches, so that the generator speed of the wind turbine generator set increases; The main control system detects whether the generator speed reaches a preset grid-connected speed.

10. The backup power supply system for a wind turbine generator set according to claim 9, characterized in that: Also includes: When the main control system detects that the generator speed reaches the preset grid-connected speed, the converter excitation constructs the motor output of the wind turbine generator, and the motor output includes at least: voltage amplitude, frequency and phase; The converter detects whether the motor output meets a preset grid-connected output condition.

11. A wind turbine generator set, characterized in that: A backup power supply system comprising a wind turbine generator set as claimed in any one of claims 1 to 9.

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