Method and device for controlling grid-connected power of wind turbine generator set

Abstract

The present disclosure relates to a method and device for controlling the off-grid power of a wind turbine. The off-grid power control method for a wind turbine includes: in response to the converter on the side of the converter being in operation, based on the rotor speed of the wind turbine, controlling the converter on the side of the converter to keep running or stop running; in the case of controlling the converter on the side of the converter to stop running, in response to the rotor speed of the wind turbine being less than a first threshold, controlling the converter excitation module to stop running. By adopting the present disclosure, it is possible to optimize the off-grid power of a wind turbine, reduce the excitation energy loss of the unit itself, effectively reduce the power generation loss of the unit, achieve the purpose of improving quality and efficiency, and enhance the economic benefits of the wind farm.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wind power generation, and more specifically, to a method and device for controlling the amount of electricity supplied to the grid by a wind power generator set. Background Art

[0002] For existing electrically excited wind turbines, in standby mode, the problem of self-consumption of electricity by electrically excited units is not fully considered and there is continuous generator excitation, which leads to an increase in the self-consumption of electricity by wind turbines. Usually, in standby conditions, the wind wheel stops rotating, the converter side stops working, and the grid side delays for three hours to disconnect the circuit breaker. During this period, the excitation module continues to work until the circuit breaker disconnects three hours later. At this time, the excitation command master control cancels it through the corresponding flag bit, and the communication protocol has determined that the excitation command has a corresponding flag bit. This control method will cause the unit to have a higher excitation capacity consumption, which is mainly manifested in the high grid power loss of the wind turbine, and the problem of self-consumption is more prominent, affecting the power revenue of the wind farm. Summary of the invention

[0003] In order to solve the above problems, the present disclosure proposes a method and device for controlling the off-grid power of a wind turbine generator set, a computing system and a computer-readable storage medium. The method and device for controlling the off-grid power of a wind turbine generator set can reduce the excitation energy loss of the set, thereby reducing the off-grid power of the set and improving the efficiency of the set.

[0004] According to one aspect of the present disclosure, a method for controlling off-grid power of a wind turbine generator set is provided, the method comprising: in response to a converter on the machine side of the converter being in operation, controlling the converter on the machine side of the converter to keep running or stop running based on the rotor speed of the wind turbine generator set; in the case of controlling the converter on the machine side of the converter to stop running, in response to the rotor speed of the wind turbine generator set being less than a first threshold, controlling the converter excitation module to stop running.

[0005] Optionally, based on the rotor speed of the wind turbine generator set, the step of controlling the converter on the machine side of the converter to keep running or stop running includes: in response to the rotor speed of the wind turbine generator set being greater than or equal to a second threshold, controlling the converter on the machine side of the converter to keep running, wherein the second threshold is greater than the first threshold; in response to the rotor speed of the wind turbine generator set being less than the second threshold, controlling the converter on the machine side of the converter to stop running.

[0006] Optionally, the off-grid power control method further includes: while controlling the converter excitation module to stop running, in response to the wind turbine generator set being in a fault triggering state, controlling the converter grid-side converter to stop running and controlling the converter grid-side circuit breaker to open.

[0007] Optionally, the off-grid power control method further includes: after controlling the grid-side converter of the converter to stop running and controlling the grid-side circuit breaker of the converter to open, controlling the wind turbine generator set to enter a fault state and stop running.

[0008] Optionally, the off-grid power control method also includes: in response to the wind turbine generator set not being in a fault trigger state, determining whether the duration of the wind turbine generator set's rotor speed being less than a first threshold is greater than or equal to a first time threshold; in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being greater than or equal to the first time threshold, controlling the inverter grid-side converter to stop running, controlling the inverter grid-side circuit breaker to open, and discharging the inverter DC bus; in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being less than the first time threshold, controlling the inverter grid-side converter, the inverter grid-side circuit breaker and the inverter DC bus to maintain the current state.

[0009] Optionally, the off-grid power control method also includes: in response to the duration of the grid-side circuit breaker of the converter being in the open state being greater than or equal to a second time threshold, controlling the water cooling system circulation pump of the wind turbine generator set to stop working, and controlling the wind turbine generator set to enter a shutdown state.

[0010] According to another aspect of the present disclosure, there is provided a grid-connected power control device for a wind turbine generator set, the grid-connected power control device comprising: a converter-side converter control unit, configured to control the converter-side converter to keep running or stop running based on the rotor speed of the wind turbine generator set in response to the converter-side converter being in running state; and a converter excitation module control unit, configured to control the converter excitation module to stop running in response to the rotor speed of the wind turbine generator set being less than a first threshold value while controlling the converter-side converter to stop running.

[0011] Optionally, the converter side converter control unit is further configured to: in response to the rotor speed of the wind turbine generator set being greater than or equal to a second threshold, control the converter side converter to keep running, wherein the second threshold is greater than the first threshold; in response to the rotor speed of the wind turbine generator set being less than the second threshold, control the converter side converter to stop running.

[0012] Optionally, the off-grid power control device also includes a grid-side control unit, which is configured to: while controlling the converter excitation module to stop running, in response to the wind turbine generator set being in a fault triggering state, control the converter grid-side converter to stop running and control the converter grid-side circuit breaker to open.

[0013] Optionally, the off-grid power control device also includes a unit control unit, which is configured to: control the wind turbine generator set to enter a fault state and stop running after the grid-side control unit controls the grid-side converter of the converter to stop running and controls the grid-side circuit breaker of the converter to open.

[0014] Optionally, the off-grid power control device also includes a grid-side control unit, which is configured to: in response to the wind turbine generator set not being in a fault triggering state, determine whether the duration of the wind turbine generator set's rotor speed being less than a first threshold is greater than or equal to a first time threshold; in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being greater than or equal to the first time threshold, control the inverter grid-side converter to stop running, control the inverter grid-side circuit breaker to open, and discharge the inverter DC bus; in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being less than the first time threshold, control the inverter grid-side converter, the inverter grid-side circuit breaker and the inverter DC bus to maintain the current state.

[0015] Optionally, the off-grid power control device also includes a unit control unit, which is configured to: in response to the duration of the grid-side circuit breaker of the converter being in an open state being greater than or equal to a second time threshold, control the water cooling system circulation pump of the wind turbine to stop working, and control the wind turbine to enter a shutdown state.

[0016] According to another aspect of the present disclosure, there is provided a computing system comprising at least one computing device and at least one storage device storing instructions, wherein the instructions, when executed by the at least one computing device, prompt the at least one computing device to execute the method for controlling the off-grid power of a wind turbine generator set as described above.

[0017] According to another aspect of the present disclosure, a computer-readable storage medium storing instructions is provided, wherein when the instructions are executed by at least one computing device, the at least one computing device is prompted to execute the above-mentioned method for controlling the off-grid power of a wind turbine generator set.

[0018] By adopting the present disclosure, it is possible to optimize the off-grid power generation of wind turbines, reduce the excitation energy loss of the units themselves, effectively reduce the power generation loss of the units, achieve the purpose of improving quality and efficiency, and enhance the economic benefits of wind farms. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or other objects and advantages of the present disclosure will become more apparent through the following description of embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 is a graph showing a given field current and power loss at different speeds;

[0021] Figure 2 is a flow chart showing a method for controlling the amount of electricity to be supplied to the grid of a wind turbine generator set according to an exemplary embodiment of the present disclosure;

[0022] Figure 3 is a flow chart showing a method for controlling off-grid power of a wind turbine generator set under a fault triggering condition according to an example of the present disclosure;

[0023] Figure 4 is a flow chart showing a method for controlling the off-grid power of a wind turbine generator set in a standby state according to an example of the present disclosure;

[0024] Figure 5 is a block diagram showing a grid-connected power control device for a wind turbine generator set according to an exemplary embodiment of the present disclosure;

[0025] Figure 6 is a block diagram illustrating a computing system including at least one computing device and at least one storage device storing instructions according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] Below, in conjunction with the accompanying drawings, a description of a specific embodiment is provided to help the reader obtain a comprehensive understanding of the method, device and / or system described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the method, device and / or system described herein will be clear. For example, the order of operations described herein is only an example and is not limited to those orders set forth herein, but can be changed as will be clear after understanding the disclosure of the present application, except for operations that must occur in a specific order. In addition, for greater clarity and simplicity, the description of features known in the art may be omitted.

[0027] Usually, the self-consumption of electric excitation units is not considered when the wind turbine generator set is in standby mode. For example, when the unit is in standby mode, the excitation command will continue to be given until the main circuit breaker is disconnected three hours later and the excitation command is cancelled; before the excitation command is cancelled, the excitation module (the device that provides stator power to the generator or synchronous motor stator) will continue to work, and the generator excitation winding will also continue to work, resulting in excitation capacity loss when the unit is in standby mode, which will increase the self-consumption of the unit, thereby affecting the electricity revenue of the wind farm.

[0028] Figure 1 is a graph showing a given field current and power loss at different speeds.

[0029] In the example, the excitation current is the current flowing through the rotor of the synchronous motor. The off-grid power is generally manifested as the self-consumption of the wind turbine, which can be understood as the power obtained from the power grid, that is, the power consumed. As mentioned above, the problem with existing units is that under standby or low wind conditions, the converter excitation module continues to work until 3 hours later when the grid side stops modulating operation and the grid side circuit breaker is disconnected, at which time the converter excitation module stops working. In the example, based on the power consumption data of the units of a wind farm under static standby conditions, Table 1 shown below is obtained.

[0030] Table 1 Power consumption of a wind farm unit under static standby conditions

[0031]

[0032] When the wind turbine is in standby condition, only the excitation module and the water cooling system remain in operation in the wind turbine. In the example, the power of the water cooling system circulating pump motor is 4KW, the DC voltage of the converter excitation module is 863V, and the excitation current is 15A, so the power is 863V15A=12.95KW. The sum of the power consumption of the above two items is 16.95KW. The calculated data is basically close to the power data consumed under static standby conditions of the unit. The loss difference of 1kW to 1.5kW is the sum of the power consumed by the unit's switching power supply, controller, driver, relay, etc.

[0033] Based on the observation of the wind farm for three consecutive months and the statistics of the number of converter circuit breakers disconnected, it can be seen that the gusts on site are obvious, and the units experience at least one small wind shutdown every day. Therefore, the annual off-grid power of a single unit can be calculated as: 12.95KW×3h×365=14108.25kWh. In the example, considering that there are a total of 149 units for on-site transformation, the annual off-grid power of 149 units can be calculated as: 14108.25kWh×149=2112857.25kWh. Calculated based on the rated power of a single unit of 2000kW, the annual off-grid power of 149 units can be equivalent to the available hours of a single unit, that is, 2112857.25kWh / 2000kW=1056.43h. It can be seen that the annual grid-connected electricity generated by the excitation of the excitation modules of the 149 units in standby condition is equivalent to the annual power generation of a 2MW unit.

[0034] For electrically excited synchronous generators for wind power, the output voltage at the generator port is usually unchanged. Through the V characteristic curve of the excitation current and the stator current, the stator current and output power of the generator at different speeds can be obtained based on the excitation current at different speeds. The excitation of a synchronous generator requires a certain amount of power. If the wind turbine rotor is at the grid-connected wind speed, then given the excitation standby, the power required for the excitation of the unit will be very large. In the example, the nameplate of the on-site electrically excited synchronous generator records the following information: the excitation rated voltage is 863V, the excitation rated current is 82A, and the excitation power is nearly 71kW. In order to reduce the excitation loss of the electrically excited synchronous generator under standby conditions, a method of gradually increasing the excitation current near the grid-connected speed can be determined. For example Figure 1 As shown, the excitation current 1 is the rated excitation current. The horizontal axis is the generator speed in rpm, the left vertical axis is the excitation current in A, or the vertical axis is the excitation power in kW. The right vertical axis is the proportion of reducing the excitation power. In the example, when the generator speed is 0 to 5rpm, the given excitation current is small (5A to 15A), which is to calculate the generator speed through the induced voltage of the generator stator winding. When the generator operating speed is close to the grid-connected speed of 7rpm, the unit excitation current is given 50A, and as the generator speed increases, the excitation current gradually increases to the rated excitation current of 82A. The excitation current setting method can significantly reduce the excitation power loss of the wind turbine under low-speed and low-wind conditions. For example, when the generator speed is 1rpm to 2rpm, the maximum power ratio that can be reduced is 94%.

[0035] According to the above analysis, the excitation loss of the wind turbine generator set in the standby state will lead to a high power generation loss. In view of the problem of high excitation loss of the wind turbine generator set, the present disclosure proposes a method and device for controlling the off-grid power of the wind turbine generator set.

[0036] Figure 2 Detailed description is a flow chart showing a method for controlling grid-connected power of a wind turbine generator set according to an exemplary embodiment of the present disclosure.

[0037] like Figure 2As shown, in step S201, in response to the converter side converter being in operation, based on the rotor speed of the wind turbine generator set, the converter side converter is controlled to keep running or stop running. In step S202, in the case of controlling the converter side converter to stop running, in response to the rotor speed of the wind turbine generator set being less than the first threshold, the converter excitation module is controlled to stop running. In the example, in response to the rotor speed of the wind turbine generator set being greater than or equal to the second threshold (for example, 6.0rpm), the converter side converter is controlled to keep running, wherein the second threshold is greater than the first threshold (for example, 2.5rpm); in response to the rotor speed of the wind turbine generator set being less than the second threshold, the converter side converter is controlled to stop running.

[0038] In the example, different control strategies may be adopted depending on whether the wind turbine generator set is in a fault trigger state or in a low wind standby state. For example, while controlling the converter excitation module to stop running, in response to the wind turbine generator set being in a fault trigger state, controlling the converter grid-side converter to stop running, and controlling the converter grid-side circuit breaker to open. Furthermore, after controlling the converter grid-side converter to stop running and controlling the converter grid-side circuit breaker to open, the wind turbine generator set is controlled to enter a fault state and stop running. For another example, in response to the wind turbine generator set not being in a fault triggering state, determine whether the duration of the wind turbine generator set's rotor speed being less than the first threshold is greater than or equal to the first time threshold (for example, 3 hours); in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being greater than or equal to the first time threshold, control the inverter grid-side converter to stop running, control the inverter grid-side circuit breaker to open, and discharge the inverter DC bus; in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being less than the first time threshold, control the inverter grid-side converter, the inverter grid-side circuit breaker, and the inverter DC bus to maintain the current state. And, in response to the duration of the inverter grid-side circuit breaker being in the open state being greater than or equal to the second time threshold (for example, 20 minutes), control the wind turbine generator set's water cooling system circulating pump to stop working, and control the wind turbine generator set to enter a shutdown state. Regarding the different control strategies adopted when the wind turbine generator set is in a fault triggering state or a low wind standby state, please refer to the following for details. Figure 3 and Figure 4 By adopting the off-grid power control method of a wind turbine generator set according to an exemplary embodiment of the present disclosure, it is possible to optimize the off-grid power of the wind turbine generator set and reduce the excitation energy loss of the set itself.

[0039] Figure 3 The flowchart shows a method for controlling the off-grid power of a wind turbine generator set under a fault triggering condition according to an example of the present disclosure.

[0040] like Figure 3As shown, in step S301, during the operation of the unit, the main control system determines in real time whether the unit has a fault (i.e., whether the fault trigger condition is met). If it is determined in step S301 that the unit has a fault (i.e., the fault trigger condition is met), the variable pitch system performs emergency retraction in step S302, and the converter torque follows the main control instruction in step S303 to reduce the load.

[0041] Subsequently, in step S304, the main control system determines the rotation speed of the wind rotor to determine whether the rotation speed of the wind rotor is lower than a predetermined rotation speed threshold (for example, 6 rpm). If it is determined in step S304 that the rotation speed of the wind rotor is lower than the predetermined rotation speed threshold, the converter on the converter side stops modulating operation in step S305, and the load switch on the converter side is opened in step S306. If it is determined in step S304 that the rotation speed of the wind rotor is greater than or equal to a given rotation speed threshold, the converter on the converter side is controlled to keep running. That is, in response to the rotation speed of the wind rotor of the wind turbine generator set being greater than or equal to a predetermined rotation speed threshold (for example, 6.0 rpm), the converter on the converter side is controlled to keep running; in response to the rotation speed of the wind rotor of the wind turbine generator set being less than the rotation speed threshold, the converter on the converter side is controlled to stop running.

[0042] Next, in step S307, the main control system determines the rotation speed of the wind rotor to determine whether the rotation speed of the wind rotor is lower than another predetermined rotation speed threshold (for example, 2.5rpm) that is lower than the predetermined rotation speed threshold. If it is determined in step S307 that the rotation speed of the wind rotor is lower than another predetermined rotation speed threshold (for example, 2.5rpm), the converter excitation module is controlled to stop working in step S308, and the generator rotor excitation current is controlled to stop. If it is determined in step S307 that the rotation speed of the wind rotor is greater than or equal to another predetermined rotation speed threshold (for example, 2.5rpm), the converter excitation module is controlled to keep working. When the converter excitation module is controlled to stop working in step S308, the converter grid-side converter is controlled to stop modulation operation in step S309, the converter circuit breaker is controlled to perform a tripping action in step S310, and the unit is controlled to enter a fault state in step S311, and the unit stops running.

[0043] By adopting Figure 3 The off-grid power control method shown can stop the converter excitation module from working in a timely manner, thereby reducing the self-excitation energy loss of the unit when it is in a fault triggering condition.

[0044] Figure 4 The flowchart shows a method for controlling the off-grid power of a wind turbine generator set in a standby state according to an example of the present disclosure.

[0045] like Figure 4As shown, after the unit is powered on, the control system starts self-checking in step S401, establishes communication with the pitch system and the converter system, and in step S402, the pitch system retracts the blades to a first predetermined angle (for example, 87.5°). In step S403, the main control system determines whether the unit has a fault. If it is determined in step S403 that the unit has a fault, the unit is controlled to enter a fault state. If it is determined in step S403 that each system of the unit is operating normally, the unit is controlled to enter a standby state in step S404, and the pitch system is controlled to open the blades to a second predetermined angle (for example, 70°) smaller than the first predetermined angle in step S405. When the unit is in the standby state, in step S406, it is determined whether the rotor speed is greater than a predetermined speed (for example, 0.5rpm). If it is determined in step S406 that the rotor speed is greater than a predetermined speed (for example, 0.5rpm), the pitch system is controlled to open the blades to a third predetermined angle (for example, 0°) smaller than the second predetermined angle in step S407, and the converter bus is controlled to pre-charge in step S408. If it is determined in step S406 that the rotor speed is less than or equal to the predetermined speed (for example, 0.5 rpm), the variable pitch system is controlled to open the pitch to a second predetermined angle (for example, 70°) that is smaller than the first predetermined angle. Next, in step S409, it is determined whether the rotor speed is greater than the predetermined speed (for example, 3.5 rpm). If it is determined in step S409 that the rotor speed is greater than the predetermined speed (for example, 3.5 rpm), in step S410, the grid-side circuit breaker of the converter is controlled to close, in step S411, the circulating pump of the water cooling system is controlled to start, in step S412, the grid-side converter of the converter is controlled to modulate and operate, and in step S413, the converter excitation module is controlled to start and the generator rotor excitation current is controlled to be given. Then, in step S414, it is determined whether the rotor speed is greater than the predetermined speed (for example, 7.2 rpm). If it is determined in step S414 that the wind rotor speed is greater than the predetermined speed (for example, 7.2 rpm), then in step S415, the load switch on the inverter side is controlled to close, and in step S416, the converter on the inverter side is controlled to enter the modulation operation state, and in step S417, maximum power point tracking (MPPT) is performed according to the wind power curve, and in step S418, the pitch system is controlled to adjust the pitch according to the blade position and pitch speed issued by the main control instruction, and in step S419, the converter system is controlled to follow the main control instruction to give a torque, and in step S420, the unit is controlled to enter the grid-connected power generation state.

[0046] Subsequently, in step S421, it is determined whether the rotor speed is lower than a predetermined speed threshold (e.g., 6.0 rpm). If it is determined in step S421 that the rotor speed is lower than the predetermined speed threshold (e.g., 6.0 rpm), then in step S422, the converter on the converter side is controlled to stop modulating operation, otherwise, the converter on the converter side is controlled to maintain modulating operation. That is, in response to the rotor speed of the wind turbine generator set being greater than or equal to the predetermined speed threshold (e.g., 6.0 rpm), the converter on the converter side is controlled to maintain operation; in response to the rotor speed of the wind turbine generator set being less than the speed threshold, the converter on the converter side is controlled to stop operation. Then, in step S423, it is determined whether the rotor speed is lower than another predetermined speed threshold (e.g., 2.5 rpm) that is lower than the predetermined speed threshold. If it is determined in step S423 that the rotor speed is lower than another predetermined speed threshold (e.g., 2.5 rpm), then in step S424, the converter excitation module is controlled to stop working and the generator rotor excitation current is controlled to stop, and in step S425, the converter side load switch is controlled to open. Furthermore, in step S426, it is determined whether the duration of the wind rotor speed being lower than another predetermined speed threshold (for example, 2.5 rpm) reaches a predetermined time threshold (for example, 3 hours). If it is determined in step S426 that the duration of the wind rotor speed being lower than another predetermined speed threshold (for example, 2.5 rpm) reaches a predetermined time threshold (for example, 3 hours), then in step S427, the grid-side converter of the converter is controlled to stop modulation operation, in step S428, the grid-side circuit breaker of the converter is controlled to open, and in step S429, the DC bus of the converter is controlled to discharge. Thereafter, in step S430, it is determined whether the opening time of the converter circuit breaker has reached another predetermined time threshold (for example, 20 minutes). If it is determined in S430 that the opening time of the converter circuit breaker has reached another predetermined time threshold (for example, 20 minutes), then in step S431, the circulating pump of the water cooling system is controlled to stop working, and the unit is controlled to enter a shutdown state.

[0047] In the example, when the unit switches from the power generation state to the low wind standby state, the wind wheel stops rotating, the inverter machine side stops working, and the grid side delays disconnecting the circuit breaker for three hours. During this period, the inverter excitation module stops exciting the generator rotor excitation winding, and the main control program performs corresponding logical judgment to cancel the inverter excitation command flag. The inverter receives the flag through CAN communication with the main control, and executes the main control command to stop the generator excitation winding excitation current and excitation voltage setting. By adopting Figure 4 The off-grid power control method shown can stop the converter excitation module from working in a timely manner, thereby reducing the self-excitation energy loss of the unit when it is in a low-wind standby condition.

[0048] Figure 5 is a block diagram showing a grid-connected power control device for a wind turbine generator set according to an exemplary embodiment of the present disclosure.

[0049] like Figure 5 As shown, according to an exemplary embodiment of the present disclosure, a grid-connected power control device 500 of a wind turbine generator set includes: a converter side converter control unit 501, configured to control the converter side converter to keep running or stop running based on the rotor speed of the wind turbine generator set in response to the converter side converter being in running state; a converter excitation module control unit 502, configured to control the converter excitation module to stop running in response to the rotor speed of the wind turbine generator set being less than a first threshold value while controlling the converter side converter to stop running.

[0050] In the example, the converter machine-side converter control unit 501 is further configured to: in response to the rotor speed of the wind turbine being greater than or equal to a second threshold, control the converter machine-side converter to keep running, wherein the second threshold is greater than the first threshold; in response to the rotor speed of the wind turbine being less than the second threshold, control the converter machine-side converter to stop running.

[0051] In the example, the off-grid power control device 500 may also include a grid-side control unit, which is configured to: while controlling the converter excitation module to stop running, in response to the wind turbine generator set being in a fault triggering state, control the converter grid-side converter to stop running and control the converter grid-side circuit breaker to open.

[0052] In the example, the off-grid power control device 500 may also include a unit control unit, which is configured to: control the wind turbine generator set to enter a fault state and stop running after the grid-side control unit controls the grid-side converter of the converter to stop running and controls the grid-side circuit breaker of the converter to open.

[0053] In the example, the off-grid power control device 500 may also include a grid-side control unit, which is configured to: in response to the wind turbine generator set not being in a fault trigger state, determine whether the duration of the wind turbine generator set's rotor speed being less than a first threshold is greater than or equal to a first time threshold; in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being greater than or equal to the first time threshold, control the inverter grid-side converter to stop running, control the inverter grid-side circuit breaker to open, and discharge the inverter DC bus; in response to the duration of the wind turbine generator set's rotor speed being less than the first threshold being less than the first time threshold, control the inverter grid-side converter, the inverter grid-side circuit breaker and the inverter DC bus to maintain the current state.

[0054] In the example, the off-grid power control device 500 may also include a unit control unit, which is configured to: in response to the duration of the grid-side circuit breaker of the converter being in an open state being greater than or equal to a second time threshold, control the water cooling system circulation pump of the wind turbine to stop working, and control the wind turbine to enter a shutdown state.

[0055] Combination of the above Figures 1 to 4 The specific operations shown are respectively Figure 5 The corresponding units in the off-grid power control device 500 of the wind turbine generator set are executed, and the specific operation details will not be repeated here. By adopting the off-grid power control device of the wind turbine generator set according to the exemplary embodiment of the present disclosure, it is possible to optimize the off-grid power of the wind turbine generator set and reduce the excitation energy loss of the unit itself.

[0056] Figure 6 is a block diagram illustrating a computing system including at least one computing device and at least one storage device storing instructions according to an exemplary embodiment of the present disclosure.

[0057] like Figure 6 As shown, the computing system 600 provided according to an exemplary embodiment of the present invention includes a computing device 601 and a storage device 602, in which computer executable instructions are stored. When the computer executable instructions are executed by the computing device 601, the grid-connected power control method of the wind turbine generator set described in any of the aforementioned embodiments is executed.

[0058] The computing device 601 is deployed in a server or client, and can also be deployed on a node device in a distributed network environment. In addition, the computing device 601 can be a PC computer, a tablet device, a personal digital assistant, a smart phone, a web application or other device capable of executing the above-mentioned instruction set. Here, the computing device is not necessarily a single computing device, but can also be any device or circuit that can execute the above-mentioned instructions (or instruction sets) individually or jointly. The computing device can also be part of an integrated control system or a system manager, or can be configured as a portable electronic device that is interconnected with an interface locally or remotely (for example, via wireless transmission). In the computing device, the processor includes a central processing unit (CPU), a graphics processing unit (GPU), a programmable logic device, a dedicated processor system, a microcontroller or a microprocessor. As an example and not a limitation, the processor also includes an analog processor, a digital processor, a microprocessor, a multi-core processor, a processor array, a network processor, etc.

[0059] According to another aspect of the present disclosure, a computer-readable storage medium storing instructions is provided, and when the instructions are executed by at least one computing device, the at least one computing device is prompted to execute the off-grid power control method of a wind turbine generator set described in any of the aforementioned embodiments. Computer-readable storage media include magnetic media such as floppy disks and tapes, optical media (including compact disk (CD) ROM and DVD ROM), magneto-optical media such as floppy disks, hardware devices such as ROM, RAM, and flash memory designed to store and execute program commands. The instructions may include language codes executable by a computer using an interpreter and machine language codes generated by a compiler.

[0060] By adopting the off-grid power control method and device of the wind turbine generator set according to the exemplary embodiment of the present disclosure, the off-grid power loss of the unit can be effectively reduced. Through the evaluation of the project example, it is verified that the off-grid power loss of the unit is reduced to achieve the expected effect. In the example, the off-grid power optimization is achieved by upgrading the converter program and the main control program. According to the data cutoff time, 16 days is used as a comparison period, and the off-grid power data is summarized as shown in Table 2 below. According to the actual situation of the wind farm, the unit goes through the process from power generation to shutdown at least once a day. For the unit in the low wind shutdown state, the grid side circuit breaker is disconnected after the grid side runs for 3 hours. During this period, the excitation module has been working and continuously consumes excitation power. As a comparison, the excitation power consumption data is reversely derived from the comparison data to analyze the effectiveness of the off-grid power optimization strategy. In the actual unit layout, the machine position is different, and it is difficult to achieve consistency in the wind speed, working conditions, heat dissipation conditions, etc. of the units on different lines. The main comparison is made before and after the upgrade of the single line program. The data of cycle 3 of line A2 is the data after the program upgrade (ie, the offline power data of line A2 is 17850).

[0061] Table 2 Evaluation table of off-grid power optimization effect

[0062]

[0063] Based on the actual data on site, it can be confirmed that after the control program is upgraded, the off-grid power optimization strategy has a more obvious effect in the comparison period. Compared with the off-grid power before the upgrade, both the period comparison and the line average value comparison have been significantly reduced. The actual data calculated by the actual data on site are consistent with the theoretical analysis, and the excitation voltage obtained in reverse is basically consistent with the theoretical value, which proves the effectiveness of the off-grid power optimization strategy.

[0064] By adopting the present disclosure, it is possible to optimize the off-grid power generation of wind turbines, reduce the excitation energy loss of the units themselves, effectively reduce the power generation loss of the units, achieve the purpose of improving quality and efficiency, and enhance the economic benefits of wind farms.

[0065] The processes, methods or algorithms disclosed herein may be transmitted to or implemented by a processing device, a controller or a computer, which may include any existing programmable electronic control unit or a dedicated electronic control unit. Similarly, the processes, methods or algorithms may be stored in a variety of forms as data and instructions that can be executed by a controller or a computer, including but not limited to information being permanently stored on a non-writable storage medium (such as a ROM device) and information being variably stored on a writable storage medium (such as a floppy disk, a tape, a CD, a RAM device, and other magnetic and optical media). The processes, methods or algorithms may also be implemented in a software executable object. Optionally, the processes, methods or algorithms may be implemented in whole or in part using suitable hardware components (such as an ASIC, an FPGA, a state machine, a controller or other hardware components or devices) or a combination of hardware components, software components and firmware components.

[0066] Although the present disclosure includes specific examples, it will be apparent to those of ordinary skill in the art that various changes in form and detail may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein will be considered to be descriptive only and not for limiting purposes. The description of the features or aspects in each example will be considered to be applicable to similar features or aspects in other examples. Suitable results may be obtained if the described techniques are performed in a different order, and / or if the components in the described systems, architectures, devices, or circuits are combined in different ways and / or replaced or supplemented with other components or their equivalents in the described systems, architectures, devices, or circuits. Therefore, the scope of the present disclosure is not limited by specific embodiments, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents will be interpreted as included in the present disclosure.

Claims

1. A method for controlling the amount of electricity that is disconnected from the grid by a wind turbine generator set, characterized in that: The off-grid power control method comprises: In response to the converter on the machine side of the converter being in an operating state, based on the rotor speed of the wind turbine generator set, controlling the converter on the machine side of the converter to keep operating or stop operating; In the case where the machine-side converter of the converter is controlled to stop operating, in response to a rotor speed of the wind turbine generator set being less than a first threshold, the excitation module of the converter is controlled to stop operating.

2. The method for controlling the off-grid electricity quantity of a wind turbine generator set according to claim 1, characterized in that: Based on the rotor speed of the wind turbine generator set, the steps of controlling the converter side of the converter to keep running or stop running include: In response to a rotor speed of the wind turbine generator set being greater than or equal to a second threshold, controlling the converter side converter of the converter to keep running, wherein the second threshold is greater than the first threshold; In response to the rotor speed of the wind turbine generator set being less than a second threshold, the machine-side converter of the converter is controlled to stop operating.

3. The method for controlling the off-grid electricity quantity of a wind turbine generator set according to claim 1, characterized in that: The off-grid power control method further includes: While controlling the converter excitation module to stop running, in response to the wind turbine generator set being in a fault triggering state, the converter grid-side converter of the converter is controlled to stop running, and the converter grid-side circuit breaker is controlled to open.

4. The method for controlling the off-grid electricity quantity of a wind turbine generator set according to claim 3, characterized in that: The off-grid power control method further includes: After the grid-side converter of the converter is controlled to stop running and the grid-side circuit breaker of the converter is controlled to open, the wind turbine generator set is controlled to enter a fault state and stop running.

5. The method for controlling the off-grid electricity quantity of a wind turbine generator set according to claim 1, characterized in that: The off-grid power control method further includes: In response to the wind turbine generator set not being in a fault triggering state, determining whether a duration during which a rotor speed of the wind turbine generator set is less than a first threshold is greater than or equal to a first time threshold; In response to the duration that the rotor speed of the wind turbine generator set is less than the first threshold being greater than or equal to the first time threshold, controlling the grid-side converter of the converter to stop running, controlling the grid-side circuit breaker of the converter to open, and discharging the DC bus of the converter; In response to the duration that the rotor speed of the wind turbine generator set is less than the first threshold being less than the first time threshold, the grid-side converter of the converter, the grid-side circuit breaker of the converter and the DC bus of the converter are controlled to maintain the current state.

6. The method for controlling the off-grid electricity quantity of a wind turbine generator set according to claim 5, characterized in that: The off-grid power control method further includes: In response to the duration that the grid-side circuit breaker of the converter is in the open state being greater than or equal to the second time threshold, a circulating pump of a water cooling system of the wind turbine generator set is controlled to stop working, and the wind turbine generator set is controlled to enter a shutdown state.

7. A wind turbine off-grid power control device, characterized in that: The off-grid power control device comprises: A converter control unit on the machine side of the converter is configured to control the converter on the machine side of the converter to keep running or stop running based on the rotor speed of the wind turbine generator set in response to the converter on the machine side of the converter being in a running state; The converter excitation module control unit is configured to control the converter excitation module to stop operating in response to a wind turbine rotor speed being less than a first threshold value while controlling the converter machine-side converter to stop operating.

8. A computing system comprising at least one computing device and at least one storage device storing instructions, characterized in that: When the instruction is executed by the at least one computing device, it prompts the at least one computing device to execute the off-grid power control method for a wind turbine generator set according to any one of claims 1-6.

9. A computer-readable storage medium storing instructions, characterized in that: When the instruction is executed by at least one computing device, the at least one computing device is prompted to execute the off-grid power control method for a wind turbine generator set according to any one of claims 1-6.

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