Load reduction control method, device, system and equipment of wind generating set and medium

Abstract

The invention discloses a load reduction control method, device, system and equipment for a wind generating set and a medium, and relates to the technical field of wind power generation. According to the embodiment of the invention, whether the connection between the wind generating set and the power grid is disconnected is detected; and in response to disconnection between the wind generating set and the power grid, adjusting the control strategies of the converter and the brake module to enable the active power output by the wind generating set to be smaller than the capacity of the converter. In other words, under the condition that the unit is disconnected from the power grid, the active power of the unit is smaller than the capacity of the converter by adjusting the control strategy of the converter and the brake module, blades do not need to be reinforced, and cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of wind power generation, and in particular to a method, device, system, equipment and medium for load reduction control of a wind power generator set. Background Art

[0002] When a wind turbine is disconnected from the power grid, if the output power of the generator suddenly becomes 0, it will bring a very large load impact to the unit, which will cause the life of the blades to be reduced, the blades to be damaged, or even the tower of the unit to collapse.

[0003] For doubly-fed units, due to the particularity of their electrical topology, the method of strengthening blades is usually adopted to adapt to the load impact caused by open circuit of the power grid.

[0004] Strengthening the blades will increase the weight of the blades and increase the cost. At the same time, the increased weight of the blades will cause the mechanical fatigue check of the unit to fail, further increasing the weight of mechanical support components such as the tower and hub, causing the total cost of the unit to increase. Summary of the invention

[0005] The embodiments of the present application provide a method, device, system, equipment and medium for load reduction control of a wind turbine generator set, which can reduce the impact of sudden load changes on the wind turbine generator set without increasing costs when the wind turbine generator set is disconnected from the power grid.

[0006] In a first aspect, an embodiment of the present application provides a load reduction control method for a wind turbine generator set, characterized in that the wind turbine generator set includes a generator, a converter and a brake module, the stator of the generator and the power grid are respectively connected to the first terminal of the converter, the rotor of the generator is connected to the second terminal of the converter, and the brake module is connected to the DC side of the converter;

[0007] The method includes:

[0008] Detect whether the connection between the wind turbine and the power grid is disconnected;

[0009] In response to the wind turbine generator set being disconnected from the power grid, the control strategies of the converter and the brake module are adjusted so that the active power output by the wind turbine generator set is less than the capacity of the converter.

[0010] In a second aspect, an embodiment of the present application provides a load reduction control device for a wind turbine generator set, characterized in that the wind turbine generator set includes a generator, a converter and a brake module, the stator of the generator, the power grid and the first terminal of the converter are respectively connected, the rotor of the generator is connected to the second terminal of the converter, and the brake module is connected to the DC side of the converter;

[0011] The device includes:

[0012] A detection module, used to detect whether the connection between the wind turbine generator set and the power grid is disconnected;

[0013] The adjustment module is used for adjusting the control strategies of the converter and the brake module in response to the wind turbine generator set being disconnected from the power grid, so that the active power output by the wind turbine generator set is less than the capacity of the converter.

[0014] In a third aspect, an embodiment of the present application provides a load reduction control system for a wind turbine generator set, comprising the wind turbine generator set as described in the first aspect and the load reduction control device as described in the second aspect.

[0015] In a fourth aspect, an embodiment of the present application provides an electronic device, the electronic device comprising:

[0016] Controller;

[0017] a memory for storing computer program instructions;

[0018] When the computer program instructions are executed by the controller, the method according to the first aspect is implemented.

[0019] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium having computer program instructions stored thereon. When the computer program instructions are executed by a processor, the method described in the first aspect is implemented.

[0020] The wind turbine generator set of the embodiment of the present application includes a generator, a converter and a brake module, the stator of the generator, the power grid and the first terminal of the converter are respectively connected, the rotor of the generator is connected to the second terminal of the converter, and the brake module is connected to the DC side of the converter; by detecting whether the connection between the wind turbine generator set and the power grid is disconnected; in response to the disconnection of the wind turbine generator set from the power grid, the control strategy of the converter and the brake module is adjusted so that the active power output by the wind turbine generator set is less than the capacity of the converter. That is, in the embodiment of the present application, when the unit is disconnected from the power grid, by adjusting the control strategy of the converter and the brake module, the active power of the unit can be made less than the capacity of the converter. For example, the capacity of the converter is about 1 / 3 of the capacity of the whole machine, that is, when the unit is disconnected from the power grid, the active power output by the unit can be maintained at about 1 / 3 of the rated power in a short time, that is, the load of the unit can be slowly reduced, thereby reducing the impact of the sudden load change on the unit, without strengthening the blades, thereby reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

[0022] Figure 1 A schematic diagram of a scenario of a load reduction control method for a wind turbine generator set provided in an embodiment of the present application;

[0023] Figure 2 A flow chart of a load reduction control method for a wind turbine generator set provided in an embodiment of the present application;

[0024] Figure 3 A schematic diagram of energy transfer when a generator operates in a super-synchronous state provided in an embodiment of the present application;

[0025] Figure 4 A schematic diagram of energy transfer when a generator operates in a subsynchronous state provided in an embodiment of the present application;

[0026] Figure 5 A schematic diagram of energy transfer when a unit is normally connected to a power grid provided in an embodiment of the present application;

[0027] Figure 6 A schematic diagram of a load reduction control process of a wind turbine generator set provided in an embodiment of the present application;

[0028] Figure 7 A structural diagram of a load reduction control device for a wind turbine generator set provided in an embodiment of the present application;

[0029] Figure 8 A structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating examples of the present application. In the accompanying drawings and the following description, at least some of the known structures and technologies are not shown to avoid unnecessary ambiguity in the present application; and, for clarity, the size of some structures may be exaggerated. In addition, the features, structures or characteristics described below may be combined in one or more embodiments in any suitable manner.

[0031] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the guyed tower and wind turbine generator set of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0032] As the power of wind turbines increases, the diameter of the impellers also increases. When the connection between the unit and the power grid is disconnected, if the output power of the unit suddenly drops (for example, suddenly drops to zero), it will bring a very large load impact to the unit, which will cause the life of the blades to be reduced, the blades to be damaged, and even the tower of the unit to collapse.

[0033] In order to reduce the impact of sudden load changes on the unit, some existing technologies mainly strengthen the blades to adapt to the load impact caused by the disconnection of the unit from the grid. Strengthening the blades will increase the weight of the blades and the cost. At the same time, the increase in blade weight will cause the unit to fail the mechanical fatigue check, and the weight of mechanical support components such as the tower and hub needs to be further increased, which will increase the total cost of the unit.

[0034] To this end, the embodiments of the present application provide a method, device and system for load reduction control of a wind turbine generator set, which can reduce the impact of sudden load changes on the wind turbine generator set without increasing costs when the wind turbine generator set is disconnected from the power grid.

[0035] The load reduction control method for a wind turbine generator set provided in the embodiment of the present application can be applied to Figure 1 The scenario shown may include a wind turbine generator set 10 and a power grid 11 . The wind turbine generator set 10 may include an impeller 100 , a gearbox 101 , a generator 102 , a converter 103 , and a brake module 104 . The generator 102 includes a stator 1021 and a rotor 1022 .

[0036] Among them, the impeller 100 is connected to the low-speed pole of the gearbox 101, the high-speed pole of the gearbox 101 is connected to the shaft of the generator 102, the stator 1021 is respectively connected to the power grid 11 and the first terminal C of the converter 103, the rotor 1022 is connected to the second terminal D of the converter 103, and the braking module 104 is connected to the DC side of the converter 103.

[0037] The impeller 100 is used to convert wind energy into mechanical energy and provide it to the gearbox 101; the gearbox 101 is used to convert low-speed mechanical energy into high-speed mechanical energy and provide it to the generator 102; the generator 102 is used to convert mechanical energy into electrical energy and feed it into the power grid 11; the brake module 104 is used to start working when the voltage of the DC bus of the converter 103 is too high, so as to reduce the voltage of the DC bus and maintain it at a stable value.

[0038] Exemplarily, the converter 103 may be a doubly-fed converter, that is, when the wind turbine generator set 10 is connected to the grid 11 , the active power output by the stator 1021 may be fed into the grid 11 , and the active power output by the rotor may also be fed into the grid 11 through the converter 103 .

[0039] The following is a detailed description of the load reduction control method, device, system, equipment and medium of the wind turbine generator set provided in the embodiments of the present application in combination with the above-mentioned scenarios and specific embodiments.

[0040] Figure 2 This is a flow chart of a load reduction control method for a wind turbine generator set provided in an embodiment of the present application. The structure of the wind turbine generator set can be seen in Figure 1 The load reduction control method can be applied to the controller of the converter.

[0041] like Figure 2 As shown, the load reduction control method of the wind turbine generator set may include the following steps:

[0042] S210 , detecting whether the connection between the wind turbine generator set 10 and the power grid 11 is disconnected.

[0043] S220 , in response to the wind turbine generator set 10 being disconnected from the power grid 11 , adjusting the control strategies of the converter 103 and the brake module 104 so that the active power output by the wind turbine generator set 10 is less than the capacity of the converter 103 .

[0044] In the above embodiment provided by the present application, when the wind turbine generator set 10 is disconnected from the power grid 11, by adjusting the control strategy of the converter 103 and the brake module 104, the active power output by the wind turbine generator set 10 can be made less than the capacity of the converter 103. Since the capacity of the converter 103 is about 1 / 3 of the capacity of the whole machine, that is, when the wind turbine generator set 10 is disconnected from the power grid 11, the active power output by the wind turbine generator set 10 can be maintained at about 1 / 3 of the rated power in a short time, so that the load of the set slowly decreases, thereby reducing the impact of the sudden load change on the set. By adopting this control strategy, there is no need to strengthen the blades, thereby greatly reducing the cost of the wind turbine generator set 10.

[0045] The above steps are described in detail below:

[0046] In S210, illustratively, whether the connection between the wind turbine generator set 10 and the grid 11 is disconnected can be determined by detecting whether the switch between the wind turbine generator set 10 and the grid 11 is disconnected. For example, if the switch between the wind turbine generator set 10 and the grid 11 is disconnected, it can be determined that the connection between the wind turbine generator set 10 and the grid 11 is disconnected. The switch between the wind turbine generator set 10 and the grid 11 can be a circuit breaker.

[0047] Exemplarily, when a fault occurs on the grid side, such as overload or short circuit, the whole machine controller can control the circuit breaker between the wind turbine generator set 10 and the grid 11 to open, so that the wind turbine generator set 10 is disconnected from the grid 11 to protect the wind turbine generator set 10.

[0048] Of course, other methods may also be used to detect whether the connection between the wind turbine generator set 10 and the power grid 11 is disconnected, which is not limited in the embodiment of the present application.

[0049] Exemplarily, when the connection between the wind turbine generator set 10 and the power grid 11 is disconnected, the wind turbine generator set 10 operates in an island formed by the stator 1021 , the converter 103 , the brake module 104 and the rotor 1022 of the generator.

[0050] In S220, when the wind turbine generator set 10 is disconnected from the power grid 11, in order to reduce the impact of sudden load changes on the wind turbine generator set 10, the control strategy of the converter 103 and the brake module 104 can be adjusted so that the electrical transmission chain of the wind turbine generator set 10 can still provide a certain power support in a short period of time when the wind turbine generator set 10 is disconnected from the power grid 11, avoiding its sudden drop (for example, sudden change to 0), thereby slowly reducing the load of the wind turbine generator set 10 and reducing the impact on the wind turbine generator set 10. Since the embodiment of the present application reduces the impact of sudden load changes on the wind turbine generator set 10 by adjusting the control strategy of the converter 103 and the brake module 104, there is no need to increase the weight of blades, towers, hubs and other components, so the cost can be reduced.

[0051] Exemplarily, the converter 103 of the embodiment of the present application can be a doubly-fed converter, and the content of the doubly-fed converter can refer to the above embodiment. In the wind turbine generator set 10, the capacity of the doubly-fed converter is about 1 / 3 of the capacity of the whole machine. The embodiment of the present application makes the active power output by the wind turbine generator set 10 less than the capacity of the converter, that is, when the wind turbine generator set 10 is disconnected from the power grid 11, the active power output by the wind turbine generator set 10 can be maintained at about 1 / 3 of the rated power in a short time, avoiding its sudden drop, thereby reducing the impact on the wind turbine generator set 10.

[0052] The embodiment of the present application does not limit the specific content of the control strategy of the converter 103 and the brake module 104. Any control strategy that can make the active power output by the wind turbine generator set 10 less than the capacity of the converter 103 can be applied to the embodiment of the present application.

[0053] For example, when the wind turbine generator set 10 is disconnected from the power grid 11 , the active power output by the wind turbine generator set 10 can be made smaller than the capacity of the converter 103 by controlling the working modes of the converter 103 and the braking module 104 .

[0054] For example, the braking module 104 may be controlled to work, and the active power fed into the DC bus by the converter 103 may be controlled to be a preset value, so that the active power output by the wind turbine generator set 10 is smaller than the capacity of the converter 103 .

[0055] like Figure 3 As shown, the converter 103 includes a grid-side module 1031 and a machine-side module 1032. The first end A of the grid-side module 1031 is connected to the power grid 11 and the stator 1021 respectively, the second end DC+ and DC- of the grid-side module 1031 are connected to the first end DC+ and DC- of the machine-side module 1032 through a DC bus, and the second end B of the machine-side module 1032 is connected to the rotor 1022.

[0056] Exemplarily, the grid-side module 1031 and the generator-side module 1032 may be composed of insulated-gate bipolar transistors (IGBT). The brake module 104 is connected between DC+ and DC-.

[0057] For example, Figure 3 As shown, a capacitor C1 is also provided between DC+ and DC-, with pin 1 of capacitor C1 connected to DC+ and pin 2 of capacitor C1 connected to DC-. Capacitor C1 is a DC support capacitor, and its main function is to smooth and filter the rectified voltage.

[0058] Exemplarily, the above S220 may include the following steps:

[0059] In response to the generator 102 operating in the super synchronous state, the grid-side module 1031 is controlled to operate in the non-controlled rectification mode;

[0060] The control machine side module 1032 provides the first reactive power for the rotor 1022 so that the parameters of the voltage output by the stator 1021 match the parameters of the converter 103;

[0061] The control unit side module 1032 feeds a first active power into the DC bus, so that the active power output by the wind turbine generator set 10 is smaller than the capacity of the converter 103;

[0062] Control the braking module 104 to work so that the voltage of the DC bus is less than a preset threshold;

[0063] The preset threshold is determined based on the capacity of the converter 103 .

[0064] The generator 102 operates in a super-synchronous state, that is, the rotation speed of the rotor 1022 is greater than the synchronous speed of the generator 102. When the wind turbine generator set 10 is disconnected from the power grid 11, the generator 102 usually operates in a super-synchronous state. At this time, in order to achieve the above-mentioned control objectives, it is necessary to adjust the control strategies of the grid-side module 1031, the machine-side module 1032 and the braking module 104.

[0065] Exemplarily, when the generator 102 operates in a super-synchronous state, the grid-side module 1031 is controlled to operate in a non-controlled rectification mode, that is, a mode in which the output current and voltage cannot be adjusted and controlled.

[0066] For example, if the grid-side module 1031 previously operates in a controllable rectification mode or other modes different from the uncontrolled rectification mode, it is necessary to control the grid-side module 1031 to switch from the controllable rectification mode or other modes different from the uncontrolled rectification mode to the uncontrolled rectification mode.

[0067] Exemplarily, if the grid-side module 1031 previously operates in the uncontrolled rectification mode, it is necessary to keep the operating mode of the grid-side module 1031 unchanged, that is, continue to control the grid-side module 1031 to operate in the uncontrolled rectification mode.

[0068] When the grid-side module 1031 operates in the uncontrolled rectification mode, since the connection between the wind turbine generator set 10 and the grid 11 is disconnected, there is no need to control the grid-side module 1031 to phase-lock the grid 11, and there is no need to control the grid-side module 1031 to control the voltage of the DC bus.

[0069] For example, if before this, the grid-side module 1031 phase-locks the grid 11 and controls the voltage of the DC bus to maintain at a preset threshold, then it is necessary to cancel the operation of the grid-side module 1031 phase-locking the grid 11 and the operation of controlling the DC bus voltage.

[0070] The first reactive power is the reactive power provided by the machine-side module 1032 to the rotor 1022. The magnitude of the first reactive power can be controlled by the controller of the converter 103. By controlling the reactive power provided by the machine-side module 1032 to the rotor 1022, the frequency and amplitude of the voltage output by the stator 1021 can be controlled to match the parameters of the converter 103, thereby ensuring the normal operation of the converter 103.

[0071] The first active power is the active power fed into the DC bus by the machine-side module 1032, that is, the active power fed into the machine-side module 1032 by the rotor 1022. Since the slip between the rotor 1022 and the stator 1021 is constant, the output power of the stator 1021 is indirectly controlled by controlling the active power fed into the DC bus by the machine-side module 1032, so that the sum of the active powers output by the stator 1021 and the rotor 1022, that is, the active power output by the wind turbine generator set 10 can be less than the capacity of the converter 103, thereby reducing the impact of sudden load changes on the set.

[0072] The output power of the stator 1021 can be fed into the DC bus through the grid-side module 1031 .

[0073] By controlling the brake module 104 to work, the brake module 104 can consume the active power fed into the DC bus by the grid-side module 1031 and the active power fed into the DC bus by the generator-side module 1032, thereby maintaining the voltage of the DC bus at a preset value.

[0074] For example, in an embodiment of the present application, by controlling the braking module 104, the voltage of the DC bus can be made less than a preset threshold, wherein the preset threshold can be determined based on the capacity of the converter 103, thereby ensuring the normal operation of the converter 103.

[0075] When the connection between the wind turbine generator set 10 and the power grid 11 is disconnected and the generator 102 operates in a super-synchronous state, the energy transfer path can be seen as follows: Figure 3 That is, the impeller 100 captures wind energy and converts it into mechanical energy, which is then transmitted to the generator 102 through the gear box 101. The generator 102 converts it into electrical energy. On the one hand, it is fed into the grid-side module 1031 through the stator 1021, and then fed into the DC bus by the grid-side module 1031; on the other hand, it is fed into the machine-side module 1032 through the rotor 1022, and then fed into the DC bus by the machine-side module 1032; when the brake module 104 is working, it consumes the active power on the DC bus to make the voltage of the DC bus less than the preset threshold.

[0076] The dotted arrow indicates that the machine-side module 1032 provides the first reactive power for the rotor 1022 .

[0077] In the embodiment of the present application, when the connection between the wind turbine generator set 10 and the power grid 11 is disconnected and the generator 102 is operating in a super-synchronous state, by controlling the operation of the braking module 104, and at the same time controlling the operating mode of the grid-side module 1031, and the active power fed into the DC bus by the machine-side module 1032, the active power output by the wind turbine generator set 10 can be made less than the capacity of the converter 103, and the voltage of the DC bus can be made less than a preset threshold value, which not only ensures the normal operation of the converter 103, but also reduces the impact of sudden load changes on the wind turbine generator set 10, without increasing the weight of components such as blades and towers, thereby reducing costs.

[0078] The converter still Figure 3 Taking the structure shown in the figure as an example, illustratively, the above S220 may include the following steps:

[0079] In response to the generator 102 operating in a subsynchronous state, the grid-side module 1031 is controlled to operate in a non-controlled rectification mode;

[0080] The control machine side module 1032 provides the second reactive power for the rotor 1022 so that the parameters of the voltage output by the stator 1021 match the parameters of the converter 103;

[0081] The grid-side module 1031 is controlled to provide the second active power to the rotor 1022 through the machine-side module 1032, so that the active power output by the wind turbine generator set 10 is less than the capacity of the converter 103;

[0082] Control the braking module 104 to work so that the voltage of the DC bus is less than a preset threshold;

[0083] The preset threshold is determined based on the capacity of the converter 103 .

[0084] The generator 102 works in a subsynchronous state, that is, the rotation speed of the rotor 1022 is less than the synchronous rotation speed of the generator 102. When the wind turbine generator set 10 is disconnected from the power grid 11 and the generator 102 works in a subsynchronous state, in order to achieve the above control objectives, the control strategies of the grid-side module 1031, the machine-side module 1032 and the brake module 104 need to be adjusted.

[0085] Exemplarily, when the generator 102 operates in a subsynchronous state, the grid-side module 1031 is controlled to provide the rotor 1022 with a second active power through the machine-side module 1032 , so that the active power output by the wind turbine generator set 10 is less than the capacity of the converter 103 .

[0086] At this time, part of the active power fed into the grid-side module 1031 by the stator 1021 is fed into the DC bus, and part is provided to the rotor 1022 through the machine-side module 1032 .

[0087] The control strategy of the brake module 104 and other control strategies of the grid-side module 1031 and the generator-side module 1032 are the same as the control strategy of the generator 102 operating in the super-synchronous state.

[0088] For example, when the generator 102 operates in a subsynchronous state, the grid-side module 1031 is controlled to operate in a non-controllable rectification mode, and the machine-side module 1032 is controlled to provide a second reactive power to the rotor 1022 so that the parameters of the voltage output by the stator 1021 match the parameters of the converter 103, and the braking module 104 is controlled to operate so that the voltage of the DC bus is less than a preset threshold.

[0089] In some embodiments, the generator 102 may also first operate in a super-synchronous state. As the speed of the generator 102 decreases, the generator 102 operates in a sub-synchronous state. At this time, the grid-side module 1031 can continue to be controlled to operate in a non-controllable rectification mode, and the braking module 104 can continue to be controlled to operate. At the same time, the machine-side module 1032 is controlled to provide a second reactive power for the rotor 1022, and the grid-side module 1031 is controlled to provide a second active power for the rotor 1022 through the machine-side module 1032, so that the active power output by the wind turbine generator set 10 is less than the capacity of the converter 103, and the voltage of the DC bus is less than a preset threshold.

[0090] When the connection between the wind turbine generator set 10 and the power grid 11 is disconnected and the generator 102 operates in a subsynchronous state, the energy transfer path can be seen in Figure 4 , that is, the impeller 100 captures wind energy and converts it into mechanical energy, which is then transmitted to the generator 102 through the gearbox 101, and the generator 102 converts it into electrical energy. The active power output by the stator 1021 is fed into the DC bus, a part of which is consumed by the brake module 104, and the other part is provided to the rotor 1022 of the generator 102 through the machine side module 1032. Among them, the active power consumed by the brake module 104 is equal to the active power fed into the DC bus by the stator 1021 minus the active power fed to the rotor 1022 by the DC bus.

[0091] The dashed arrow indicates the second reactive power provided by the machine-side module 1032 to the rotor 1022 .

[0092] In the embodiment of the present application, when the connection between the wind turbine generator set 10 and the power grid 11 is disconnected and the generator 102 is operating in a subsynchronous state, by controlling the operation of the braking module 104, and at the same time controlling the operating mode of the grid-side module 1031, and the active power fed into the rotor 1022, the active power output by the wind turbine generator set 10 can be made less than the capacity of the converter 103, and the voltage of the DC bus can be made less than a preset threshold value, which not only ensures the normal operation of the converter 103, but also reduces the impact of sudden load changes on the wind turbine generator set 10, without increasing the weight of components such as blades and towers, thereby reducing costs.

[0093] In some embodiments, the braking module 104 includes a switch unit K1 and an energy discharge unit R1, and the switch unit K1 and the energy discharge unit R1 are connected in series and then in parallel with the DC bus. Figure 3 As shown, one end of the switch unit K1 is connected to one end of the resistor R1, the other end of the switch unit K1 is connected to DC+, and the other end of the resistor R1 is connected to DC-.

[0094] Exemplarily, the energy dissipation unit R1 may be a resistor, that is, the active power on the DC bus is consumed by the resistor R1 so that the voltage of the DC bus is less than a preset threshold.

[0095] Exemplarily, when the generator 102 operates in a super-synchronous state, the above-mentioned “controlling the braking module to operate so that the voltage of the DC bus is less than a preset threshold” may include the following steps:

[0096] The switch unit K1 is controlled to be turned on to discharge the active power fed into the DC bus by the grid-side module 1031 and the machine-side module 1032 through the energy discharge unit R1, so that the voltage of the DC bus is less than a preset threshold.

[0097] For example, when the switch unit K1 is closed, the brake module 104 starts to discharge energy, and when the switch unit K1 is opened, the brake module 104 does not start to discharge energy. By controlling the closing and opening of the switch unit K1, the voltage of the DC bus can be maintained at a stable value.

[0098] For example, Figure 3 As shown, when the generator 102 operates in the super synchronous state, the resistor R1 consumes the active power fed into the DC bus by the grid-side module 1031 and the active power fed into the DC bus by the generator-side module 1032 .

[0099] For example, Figure 4 As shown, when the generator 102 operates in a subsynchronous state, the resistor R1 consumes the active power fed into the DC bus by the grid-side module 1031 .

[0100] The embodiment of the present application connects the braking module 104 in parallel between the grid-side module 1031 and the machine-side module 1032, and reasonably controls the on and off of the switch unit K1, so that the voltage of the DC bus can be further maintained at a stable value when the active power output by the wind turbine generator set 10 is less than the capacity of the converter 103, thereby ensuring the stability of the island system.

[0101] Still Figure 3 Taking the structure of the converter shown in FIG. 1 as an example, in some embodiments, the load reduction control method of the wind turbine generator set may further include the following steps:

[0102] In response to the wind turbine generator set 10 being connected to the grid 11, the grid-side module 1031 is controlled to operate in the inverter mode, and the grid-side module 1031 is controlled to phase-lock the grid, so that the voltage of the DC bus controlled by the grid-side module 1031 is maintained at a preset threshold value;

[0103] The third active power output by the stator 1021 is controlled to be fed into the power grid 11 , and the fourth active power output by the rotor 1022 is controlled to be fed into the power grid 11 through the converter 103 .

[0104] Exemplarily, when the wind turbine generator set 10 is not disconnected from the power grid 11, that is, the wind turbine generator set 10 operates normally at rated power, the control strategy of each module is as follows:

[0105] The grid-side module 1031 is controlled to work in the inverter mode, and the grid-side module 1031 is controlled to phase-lock the grid 11 , so that the voltage of the DC bus controlled by the grid-side module 1031 is maintained at a preset threshold.

[0106] The control machine side module 1032 works in the rectification mode to convert the AC power output by the rotor 1022 into DC power and send it to the grid side module 1031, so that the grid side module 1031 is inverted into AC power and fed into the grid 11; at the same time, the control machine side module 1032 provides reactive power for the rotor 1022. At this time, the brake module 104 does not work, that is, the switch unit K1 is disconnected.

[0107] When the wind turbine generator set 10 is not disconnected from the power grid 11, the generator 102 operates in a super-synchronous state. The energy transfer path can be seen in Figure 5 , that is, the impeller 100 captures wind energy and converts it into mechanical energy, which is then transmitted to the generator 102 through the gearbox 101, and the generator 102 converts it into electrical energy. The active power output by the stator 1021 is fed into the power grid 11, and the active power output by the rotor 1022 is fed into the power grid 11 through the machine-side module 1032 and the grid-side module 1031. At the same time, the machine-side module 1032 is also responsible for providing reactive power, i.e., excitation reactive power, to the rotor 1022. The dotted arrow indicates that the machine-side module 1032 provides reactive power to the rotor 1022.

[0108] In the embodiment of the present application, when the wind turbine generator set 10 is not disconnected from the power grid 11, the wind turbine generator set 10 can operate normally at rated power by controlling the working modes of the grid-side module 1031 and the machine-side module 1032 and controlling the braking module 104 to not work.

[0109] In some embodiments, the load reduction control method of the wind turbine generator set may further include the following steps:

[0110] In response to the rotation speed of the generator 102 reaching the grid-off rotation speed, the converter 103 is controlled to stop modulation.

[0111] For example, as the blades are retracted, the ability of the blades to absorb wind energy decreases, and the speed of the generator 102 decreases accordingly. When the speed of the generator 102 is reduced to the off-grid speed, the wind turbine 10 has achieved a process of slow load reduction. At this time, the converter 103 can be controlled to stop modulation, that is, the grid-side module 1031, the machine-side module 1032 and the brake module 104 are all controlled to stop working, thereby shutting down the wind turbine 10.

[0112] In the embodiment of the present application, when the wind turbine 10 is disconnected from the power grid 11, the load of the wind turbine 10 can be slowly reduced by adjusting the control strategy of the converter 103 and the brake module 104 until the rotation speed of the generator 102 reaches the off-grid rotation speed, and the wind turbine 10 stops working, thereby reducing the impact of sudden load changes on the wind turbine 10, eliminating the need to increase the weight of components such as blades and towers, and reducing costs.

[0113] Below through Figure 6 The entire control process of the wind turbine generator set 10 and the power grid 11 from connection to disconnection is described as follows:

[0114] S610: The wind turbine generator set 10 operates normally at rated power.

[0115] S620, control the grid-side module 1031 to work in the inverter mode; control the grid-side module 1031 to phase-lock the grid 11, so that the voltage of the DC bus controlled by the grid-side module 1031 is maintained at a preset threshold; control the grid-side module 1031 to feed the active power input by the machine-side module 1032 into the grid 11; control the machine-side module 1032 to provide excitation reactive power for the rotor 1022; control the brake module 104 not to work.

[0116] S630, detecting whether the connection between the wind turbine generator set 10 and the power grid 11 is disconnected, if disconnected, executing S640, if not disconnected, returning to execute S620.

[0117] S640, when the generator 102 operates in the super-synchronous state, the grid-side module 1031 is controlled to operate in the non-controllable rectification mode; the machine-side module 1032 is continued to be controlled to provide excitation reactive power for the rotor 1022; at the same time, the active power fed into the DC bus by the machine-side module 1032 is controlled so that the active power output by the wind turbine generator set 10 is less than the capacity of the converter 103; the switch unit K1 of the brake module 104 is controlled to be closed so as to consume the active power on the DC bus through the resistor R1 so that the voltage of the DC bus is less than the preset threshold.

[0118] S650, when the generator 102 operates in a subsynchronous state, the grid-side module 1031 is controlled to provide active power to the rotor 1022 through the machine-side module 1032, and other control strategies of the grid-side module 1031 and the machine-side module 1032 in the island system and the control strategy of the brake module 104 remain unchanged.

[0119] S660: When the rotation speed of the generator 102 reaches the off-grid rotation speed, the grid-side module 1031, the generator-side module 1032 and the brake module 104 are all controlled to stop working, and the wind turbine generator set 10 is shut down.

[0120] This embodiment of the present application utilizes the characteristic that the capacity of the doubly-fed converter is approximately 1 / 3 of the capacity of the entire machine. When the wind turbine 10 is disconnected from the power grid 11, by adjusting the control strategies of the grid-side module 1031, the machine-side module 1032 and the brake module 104, the electrical transmission chain of the wind turbine 10 can still provide a certain amount of power support for a short period of time when the wind turbine 10 is disconnected from the power grid 11, thereby slowly decreasing the load of the wind turbine 10 and reducing the impact of sudden load changes on the wind turbine 10. The entire process does not require increasing the weight of components such as blades and towers, thereby reducing costs.

[0121] Based on the same inventive concept, the present application also provides a load reduction control device for a wind turbine generator set. Figure 7 The load reduction control device for a wind turbine generator set provided in an embodiment of the present application is described in detail.

[0122] Figure 7 A structural diagram of a load reduction control device for a wind turbine generator set provided in an embodiment of the present application, such as Figure 7 As shown, the load reduction control device of the wind turbine generator set may include:

[0123] A detection module 710 is used to detect whether the connection between the wind turbine generator set and the power grid is disconnected;

[0124] The adjustment module 720 is used to adjust the control strategy of the converter and the brake module in response to the wind turbine generator set being disconnected from the power grid, so that the active power output by the wind turbine generator set is less than the capacity of the converter.

[0125] The wind turbine generator set of the embodiment of the present application includes a generator, a converter and a brake module, the stator of the generator and the grid are respectively connected to the first terminal of the converter, the rotor of the generator is connected to the second terminal of the converter, and the brake module is connected to the DC side of the converter; by detecting whether the connection between the wind turbine generator set and the grid is disconnected; in response to the disconnection of the wind turbine generator set from the grid, the control strategy of the converter and the brake module is adjusted so that the active power output by the wind turbine generator set is less than the capacity of the converter. That is, in the embodiment of the present application, when the unit is disconnected from the grid, by adjusting the control strategy of the converter and the brake module, the active power of the unit can be made less than the capacity of the converter, because the capacity of the converter is about 1 / 3 of the capacity of the whole machine, that is, when the unit is disconnected from the grid, the active power output by the unit can be maintained at about 1 / 3 of the rated power in a short time, so that the load of the unit slowly decreases, thereby reducing the impact of the sudden change of load on the unit. By adopting this control strategy, there is no need to strengthen the blades, thereby greatly reducing the cost of the wind turbine generator set 10.

[0126] In some embodiments, the converter includes a grid-side module and a machine-side module, a first end of the grid-side module is connected to the grid and the stator respectively, a second end of the grid-side module is connected to the first end of the machine-side module through a DC bus, and a second end of the machine-side module is connected to the rotor;

[0127] The adjustment module 720 is specifically used for:

[0128] In response to the generator operating in a super synchronous state, controlling the grid-side module to operate in a non-controlled rectification mode;

[0129] The control machine side module provides a first reactive power for the rotor so that the parameters of the voltage output by the stator match the parameters of the converter;

[0130] Controlling the first active power fed into the DC bus by the machine-side module so that the active power output by the wind turbine generator set is less than the capacity of the converter;

[0131] Control the brake module to work so that the voltage of the DC bus is less than a preset threshold;

[0132] The preset threshold is determined based on the capacity of the converter.

[0133] In some embodiments, the converter includes a grid-side module and a machine-side module, a first end of the grid-side module is connected to the grid and the stator respectively, a second end of the grid-side module is connected to the first end of the machine-side module through a DC bus, and a second end of the machine-side module is connected to the rotor;

[0134] The adjustment module 720 is specifically used for:

[0135] In response to the generator operating in a subsynchronous state, controlling the grid-side module to operate in a non-controlled rectification mode;

[0136] The control machine side module provides a second reactive power for the rotor so that the parameters of the voltage output by the stator match the parameters of the converter;

[0137] The grid-side module is controlled to provide a second active power to the rotor through the machine-side module, so that the active power output by the wind turbine generator set is less than the capacity of the converter;

[0138] Control the brake module to work so that the voltage of the DC bus is less than a preset threshold;

[0139] The preset threshold is determined based on the capacity of the converter.

[0140] In some embodiments, the braking module includes a switch unit and an energy discharge unit, and the switch unit and the energy discharge unit are connected in series and then in parallel with the DC bus;

[0141] The adjustment module 720 is specifically used for:

[0142] The switch unit is controlled to be turned on to discharge the active power fed into the DC bus by the grid-side module and the machine-side module through the energy discharge unit, so that the voltage of the DC bus is less than a preset threshold.

[0143] In some embodiments, the converter includes a grid-side module and a machine-side module, a first end of the grid-side module is connected to the grid and the stator respectively, a second end of the grid-side module is connected to the first end of the machine-side module through a DC bus, and a second end of the machine-side module is connected to the rotor;

[0144] The adjustment module 720 is further used to control the grid-side module to operate in the inverter mode, and control the grid-side module to phase-lock the grid, so that the voltage of the DC bus controlled by the grid-side module is maintained at a preset threshold;

[0145] The third active power output by the stator is controlled to be fed into the power grid, and the fourth active power output by the rotor is controlled to be fed into the power grid through the converter.

[0146] In some embodiments, the adjustment module 720 is further configured to control the converter to stop modulation in response to the rotation speed of the generator reaching the off-grid rotation speed.

[0147] The load reduction control device for a wind turbine generator set provided in the embodiment of the present application can achieve Figure 3 and Figure 6 To avoid repetition, the various processes in the embodiment of the load reduction control method for a wind turbine generator set are not described again.

[0148] Based on the same inventive concept, an embodiment of the present application also provides a load reduction control system for a wind turbine generator set, including the wind turbine generator set and the load reduction control device of the wind turbine generator set in the above embodiment. The specific details can be found in the above embodiment. For the sake of concise description, they will not be repeated here.

[0149] Based on the same inventive concept, the embodiment of the present application also provides an electronic device, which may be, for example, a tablet computer, a notebook computer, a handheld computer, etc. Figure 8 The electronic device provided in the embodiments of the present application is described in detail.

[0150] like Figure 8 As shown, the electronic device may include a controller 801 and a memory 802 for storing computer program instructions.

[0151] The controller 801 may include a central processing unit (CPU) or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0152] The memory 802 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 802 may include a hard disk drive (HDD), a floppy disk drive, a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive or a combination of two or more of these. In one example, the memory 802 may include a removable or non-removable (or fixed) medium, or the memory 802 is a non-volatile solid-state memory. In one example, the memory 802 may be a read-only memory (ROM). In one example, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically rewritable ROM (EAROM) or a flash memory or a combination of two or more of these.

[0153] The controller 801 reads and executes the computer program instructions stored in the memory 802 to implement Figure 3 and Figure 6 The method in the embodiment shown in the figure is achieved Figure 3 and Figure 6 The corresponding technical effects achieved by executing the method in the illustrated embodiment are not described in detail here for the sake of brevity.

[0154] In one example, the electronic device may further include a communication interface 803 and a bus 804. Figure 8 As shown, the controller 801, the memory 802, and the communication interface 803 are connected via a bus 804 and communicate with each other.

[0155] The communication interface 803 is mainly used to implement communication between various modules, devices and / or equipment in the embodiments of the present application.

[0156] Bus 804 includes hardware, software or both, and each component of electronic device is coupled to each other.For example, but not limitation, bus 804 may include accelerated graphics port (Accelerated Graphics Port, AGP) or other graphics bus, enhanced industry standard architecture (Extended Industry Standard Architecture, EISA) bus, front side bus (Front Side Bus, FSB), hypertransmission (Hyper Transport, HT) interconnection, industry standard architecture (IndustryStandard Architecture, ISA) bus, infinite bandwidth interconnection, low pin count (LPC) bus, memory bus, micro channel architecture (MCA) bus, peripheral component interconnection (PCI) bus, PCI-Express (PCI-X) bus, serial advanced technology attachment (SATA) bus, video electronics standard association local (VLB) bus or other suitable bus or two or more of these combinations. In appropriate cases, bus 804 may include one or more buses. Although the present application embodiment describes and shows a specific bus, the application considers any suitable bus or interconnection.

[0157] The electronic device can execute the load reduction control method of the wind turbine generator set in the embodiment of the present application after detecting whether the connection between the wind turbine generator set and the power grid is disconnected, thereby realizing the combination Figure 3 and Figure 6 The load reduction control method of the wind turbine generator set described Figure 7 A load reduction control device for a wind turbine generator set is described.

[0158] In addition, in combination with the load reduction control method for a wind turbine generator set in the above embodiment, the embodiment of the present application can provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by a processor, any of the load reduction control methods for a wind turbine generator set in the above embodiment is implemented.

[0159] It should be clear that the present application is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present application is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present application.

[0160] The functional blocks shown in the above block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), appropriate firmware, plug-in, function card, etc. When implemented in software, the elements of the present application are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or communication link by a data signal carried in a carrier. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (Radio Frequency, RF) links, etc. The code segment can be downloaded via a computer network such as the Internet, an intranet, etc.

[0161] It should also be noted that the exemplary embodiments mentioned in this application describe some methods or systems based on a series of steps or devices. However, this application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be performed simultaneously.

[0162] The above reference is according to the method of the present application embodiment, the flow chart of the device (system) and the computer program product and / or the block diagram of the present application embodiment. It should be understood that each square box in the flow chart and / or the block diagram and the combination of each square box in the flow chart and / or the block diagram can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine so that these instructions executed by the processor of the computer or other programmable data processing device enable the realization of the function / action specified in one or more square boxes of the flow chart and / or the block diagram. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field programmable logic circuit. It can also be understood that each square box in the block diagram and / or the flow chart and the combination of the square boxes in the block diagram and / or the flow chart can also be realized by the dedicated hardware that performs the specified function or action, or can be realized by the combination of dedicated hardware and computer instructions.

[0163] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A load reduction control method for a wind turbine generator set, characterized in that: The wind turbine generator set comprises a generator, a converter and a brake module, wherein the stator and the grid of the generator are respectively connected to the first terminal of the converter, the rotor of the generator is connected to the second terminal of the converter, and the brake module is connected to the DC side of the converter; The method comprises: Detecting whether the connection between the wind turbine generator set and the power grid is disconnected; In response to the wind turbine generator set being disconnected from the power grid, the control strategies of the converter and the brake module are adjusted so that the active power output by the wind turbine generator set is less than the capacity of the converter.

2. The method according to claim 1, characterized in that: The converter comprises a grid-side module and a machine-side module, wherein a first end of the grid-side module is connected to the grid and the stator respectively, a second end of the grid-side module is connected to the first end of the machine-side module via a DC bus, and a second end of the machine-side module is connected to the rotor; The step of adjusting the control strategy of the converter and the brake module so that the active power output by the wind turbine generator set is less than the capacity of the converter includes: In response to the generator operating in a super-synchronous state, controlling the grid-side module to operate in a non-controllable rectification mode; Controlling the machine-side module to provide a first reactive power for the rotor so that parameters of the voltage output by the stator match parameters of the converter; Controlling the first active power fed into the DC bus by the machine-side module so that the active power output by the wind turbine generator set is less than the capacity of the converter; Controlling the braking module to work so that the voltage of the DC bus is less than a preset threshold; The preset threshold is determined based on the capacity of the converter.

3. The method according to claim 1 or 2, characterized in that: The converter comprises a grid-side module and a machine-side module, wherein a first end of the grid-side module is connected to the grid and the stator respectively, a second end of the grid-side module is connected to the first end of the machine-side module via a DC bus, and a second end of the machine-side module is connected to the rotor; The step of adjusting the control strategy of the converter and the brake module so that the active power output by the wind turbine generator set is less than the capacity of the converter includes: In response to the generator operating in a subsynchronous state, controlling the grid-side module to operate in a non-controllable rectification mode; Controlling the machine-side module to provide a second reactive power for the rotor so that the parameters of the voltage output by the stator match the parameters of the converter; Controlling the grid-side module to provide a second active power to the rotor through the machine-side module, so that the active power output by the wind turbine generator set is less than the capacity of the converter; Controlling the braking module to work so that the voltage of the DC bus is less than a preset threshold; The preset threshold is determined based on the capacity of the converter.

4. The method according to claim 2, characterized in that The braking module comprises a switch unit and an energy discharge unit, wherein the switch unit and the energy discharge unit are connected in series and then connected in parallel with the DC bus; The step of controlling the braking module to operate so that the voltage of the DC bus is less than a preset threshold value includes: The switch unit is controlled to be turned on, so as to discharge the active power fed into the DC bus by the grid-side module and the machine-side module through the energy discharge unit, so that the voltage of the DC bus is less than a preset threshold.

5. The method according to claim 1, characterized in that: The converter comprises a grid-side module and a machine-side module, wherein a first end of the grid-side module is connected to the grid and the stator respectively, a second end of the grid-side module is connected to the first end of the machine-side module via a DC bus, and a second end of the machine-side module is connected to the rotor; The method further comprises: In response to the wind turbine generator set being connected to the power grid, controlling the grid-side module to operate in an inverter mode, and controlling the grid-side module to phase-lock the power grid, so that the grid-side module controls the voltage of the DC bus to be maintained at a preset threshold; The third active power output by the stator is controlled to be fed into a power grid, and the fourth active power output by the rotor is controlled to be fed into a power grid through the converter.

6. The method according to claim 3, characterized in that The method further comprises: In response to the rotation speed of the generator reaching a grid-off rotation speed, the converter is controlled to stop modulation.

7. A load reduction control device for a wind turbine generator set, characterized in that: The wind turbine generator set comprises a generator, a converter and a brake module, wherein the stator and the grid of the generator are respectively connected to the first terminal of the converter, the rotor of the generator is connected to the second terminal of the converter, and the brake module is connected to the DC side of the converter; The device comprises: A detection module, used to detect whether the connection between the wind turbine generator set and the power grid is disconnected; The adjustment module is used for adjusting the control strategies of the converter and the braking module in response to the wind turbine generator set being disconnected from the power grid, so that the active power output by the wind turbine generator set is less than the capacity of the converter.

8. A load reduction control system for a wind turbine generator set, characterized in that: It comprises a wind turbine generator set as claimed in any one of claims 1 to 6 and a load reduction control device for a wind turbine generator set as claimed in claim 7.

9. An electronic device, characterized in that: The electronic device comprises: Controller; a memory for storing computer program instructions; When the computer program instructions are executed by the controller, the method according to any one of claims 1 to 6 is implemented.

10. A computer-readable storage medium having computer program instructions stored thereon, characterized in that: When the computer program instructions are executed by a processor, the method according to any one of claims 1 to 6 is implemented.

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