Offshore wind farm operation and maintenance self-power supply system starting method based on network construction type wind turbine

Abstract

The application discloses a kind of based on network type fan's offshore wind farm operation and maintenance self-powered system starting method, for the problem of high cost of existing diesel generator or energy storage system as wind farm off-grid operation during operation and maintenance system main power supply, the application proposes a kind of based on network type fan's offshore wind farm operation and maintenance self-powered system starting method, through the coordinated control of network type wind turbine and small capacity energy storage equipment, the smooth start of off-grid operation wind farm operation and maintenance system is realized, and after starting, wind turbine can be used as operation and maintenance system main power supply.Compared with existing scheme, the application can significantly reduce engineering construction cost, effectively solve the power supply problem of operation and maintenance system generated by the asynchronous construction of offshore wind farm and onshore access system line, has significant economic benefits and good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of new energy power generation technology, specifically relating to a startup method for an offshore wind farm operation and maintenance self-power supply system based on grid-type wind turbines. Background Technology

[0002] While offshore wind power is developing rapidly, some problems in the construction of wind farms have gradually emerged, one of the most significant being the asynchronous construction of wind farms and onshore grid connection lines. The completion time of offshore wind farms is often influenced by new energy power generation policies, while the construction of onshore AC power grids is mainly led by the local power grid company. This can easily lead to situations where the wind farm and its transmission cables are completed before the supporting grid connection lines are even finished. In such cases, the offshore wind farm will be unable to connect to the grid for a period of time. During this period, to ensure the environmental conditions for the wind turbine equipment, it is necessary to maintain the continuous and reliable operation of the offshore wind farm's operation and maintenance system. Therefore, the power supply for the operation and maintenance system during the off-grid operation of offshore wind farms becomes a pressing issue that needs to be addressed.

[0003] Existing solutions consider using diesel generators or energy storage devices to provide power for the self-powered operation and maintenance system of offshore wind farms during off-grid operation. However, as the scale of offshore wind farms continues to increase, the total power demand of the self-powered operation and maintenance system of offshore wind farms is also increasing, and it needs to operate continuously for a long period of time. Using diesel generators or energy storage devices as the main power source is not only uneconomical, but also faces unacceptable constraints such as insufficient land for construction.

[0004] With the continuous development of wind power technology, the flexibility of wind power control systems has significantly improved. During off-grid operation of offshore wind farms, a more economical and feasible solution is to adopt a grid-type control strategy, using wind turbine generators as the primary power source for the self-powered operation and maintenance system, while simultaneously employing small-capacity energy storage devices as the starting power source for the wind turbine generators. The biggest challenge in this system is achieving smooth startup under off-grid conditions through the coordinated control of energy storage devices with the turbine-side converters and grid-side converters. Therefore, there is an urgent need to propose a startup method for the self-powered operation and maintenance system of offshore wind farms based on grid-type wind turbines. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of high costs associated with existing systems that use diesel generators or energy storage systems as the main power source for the operation and maintenance system of offshore wind farms during off-grid operation. This invention provides a method for starting up a self-powered operation and maintenance system for offshore wind farms based on grid-connected wind turbines. This method only requires the installation of a small-capacity energy storage device on a single wind turbine, which enables the smooth start-up of offshore wind farms under off-grid conditions. After startup, the wind turbine can be used as the main power source for the operation and maintenance system, which can significantly reduce engineering construction costs.

[0006] To achieve the above-mentioned objectives, this method adopts the following technical solution:

[0007] A method for starting up an offshore wind farm operation and maintenance self-powered system based on grid-connected wind turbines, characterized in that the offshore wind farm operation and maintenance self-powered system based on grid-connected wind turbines includes: an energy storage battery, a bidirectional DC / DC converter, a wind turbine generator, a wind turbine generator-side converter, a wind turbine DC bus, a wind turbine grid-side converter, a wind turbine step-up transformer, a wind turbine circuit breaker, an offshore AC bus, an offshore substation, a wind farm transmission cable, and an onshore control center circuit breaker; the wind turbine generator is connected to the wind turbine generator-side converter, the DC bus, and... The grid-side converter connects to the offshore AC grid, and then the voltage is stepped up to the offshore AC bus level through the wind turbine step-up transformer. After passing through the wind turbine circuit breaker, it is connected to the offshore AC bus. Multiple offshore wind turbines converge on the offshore AC bus and are stepped up to the onshore AC bus level through the offshore substation. Then, they are connected to the onshore AC grid through the offshore wind power transmission cable and the onshore control center circuit breaker. During the off-grid operation of the wind farm, the onshore control center circuit breaker is in the open state, and the offshore wind farm is not connected to the onshore AC grid.

[0008] During the off-grid operation of the offshore wind farm based on grid-connected wind turbines, one wind turbine is selected as the self-use power source for wind farm operation and maintenance and connected to the grid for power generation. The converters of the remaining wind turbines are locked, and only the self-use power system for operation and maintenance is in operation. Only the wind turbine used as the self-use power source for wind farm operation and maintenance needs to be equipped with energy storage batteries and bidirectional DC / DC converters. The structure of the remaining wind turbines is the same as that of conventional wind turbine units.

[0009] The method for starting up the self-powered operation and maintenance system of offshore wind farms based on grid-connected wind turbines is characterized by the following:

[0010] The system startup process begins by starting the energy storage battery and the bidirectional DC / DC converter. The control strategy of the bidirectional DC / DC converter is used to adjust the DC bus voltage of the wind turbine to the rated value.

[0011] Start the grid-side converter of the wind turbine that serves as the self-use power source for the wind farm's operation and maintenance, close the wind turbine circuit breaker, and establish the offshore AC grid voltage through the grid-type virtual synchronous machine control strategy of the wind turbine grid-side converter;

[0012] After the offshore AC grid voltage is established, the energy storage battery supplies power to the wind turbine's self-use power system through a bidirectional DC / DC converter and a wind turbine grid-side converter.

[0013] Start the wind turbine-side converter and wind turbine generator, which serve as the self-use power source for the wind farm's operation and maintenance. By adjusting the active power reference value of the converter, gradually increase the output active power of the wind turbine to a first set value. The first set value is given based on the self-use power load of a single wind turbine.

[0014] The circuit breakers of other wind turbines in the wind farm are closed one by one to supply power to the self-power supply system of other wind turbines. The power reference value of the turbine-side converter, which serves as the self-power supply for the wind farm's operation and maintenance, is gradually increased. The output active power of the wind turbine is adjusted to the second set value, which is given according to the self-power load of all wind turbines in the wind farm.

[0015] Since the grid-side converter of the wind turbine adopts the grid-type virtual synchronous machine control strategy and the bidirectional DC / DC converter adopts the constant DC bus voltage control strategy, when the active power output of the wind turbine matches the self-powered load of the wind farm operation and maintenance, the power supply of the entire system will be provided entirely by the wind turbine unit, and the energy storage system will only serve as a regulating power source to smooth the fluctuation of wind power output and maintain the constant DC bus voltage of the wind turbine.

[0016] Once the system startup process is complete, the entire offshore wind farm's off-grid operation and maintenance self-powered system can operate stably for a long period.

[0017] Furthermore, the bidirectional DC / DC converter adopts a constant DC bus voltage control strategy, which is responsible for establishing the DC bus voltage of the wind turbine during system startup and maintaining the stability of the DC bus voltage of the wind turbine during operation. The constant DC bus voltage control strategy of the bidirectional DC / DC converter is mainly realized through the outer loop of DC bus voltage control and the inner loop of current control.

[0018] Furthermore, the wind turbine grid-side converter, which serves as the self-use power source for wind farm operation and maintenance, adopts a grid-type virtual synchronous machine control strategy. This strategy is responsible for establishing the offshore AC grid voltage during system startup and maintaining the stability of the AC grid during operation. The grid-type virtual synchronous machine control strategy is implemented through a voltage reference value calculation module, a voltage outer loop controller, and a current inner loop controller. The voltage reference value calculation module provides voltage and frequency support for the self-use power supply system by simulating the mechanical and excitation equations of a traditional synchronous generator.

[0019] In the voltage reference value calculation module, the reference phase θ is calculated according to the following method. g :

[0020] θ g (k+1)=∫ω g (k+1)dt

[0021]

[0022] Where, θ g (k+1) is the reference phase for the next sampling period, ω g (k+1) is the angular frequency of the next sampling period, ω g (k) is the angular frequency of this sampling period, ωn P is the rated angular frequency. gref P is the active power reference value. g (k) represents the active power in this sampling period, J represents the virtual rotor moment of inertia, and D... p This is the active damping coefficient.

[0023] In the voltage reference value calculation module, the d-axis voltage reference value u is calculated according to the following method. gdref :

[0024]

[0025] Among them, u gdref (k+1) is the d-axis voltage reference value for the next sampling period, |U g (k)| represents the voltage amplitude during this sampling period, U ref Q is the reference value for voltage amplitude. gref Q is the reactive power reference value. g (k) represents the reactive power in this sampling period, K is the virtual excitation coefficient, and D q This is the reactive damping coefficient.

[0026] Furthermore, the wind turbine-side converter, which serves as the self-consumption power supply for wind farm operation and maintenance, adopts a constant active and reactive power control strategy. Its active power command is given as a first set value and a second set value at different stages of the system startup process. The first set value is given based on the self-consumption power load of a single wind turbine, and the second set value is given based on the sum of the self-consumption power load of all wind turbines. It is responsible for providing active power supply for wind turbine operation and maintenance during off-grid operation. The control strategy of the wind turbine-side converter is implemented through a power outer loop controller and a current inner loop controller.

[0027] The beneficial effects of this invention are:

[0028] By adopting the technical solution of this invention, only a small-capacity energy storage device needs to be installed on a single wind turbine to enable the smooth startup of the wind farm operation and maintenance system under off-grid operation conditions. After startup, the wind turbine can be used as the main power source for the operation and maintenance system, which can significantly reduce engineering construction costs. It can effectively solve the startup problem of off-grid wind farm operation and maintenance system caused by the asynchronous construction of offshore wind farms and onshore grid connection lines, and has significant economic benefits and good application prospects. Attached Figure Description

[0029] Figure 1 This is a flowchart of the self-powered system startup method for offshore wind farm operation and maintenance based on grid-type wind turbines according to the present invention.

[0030] Figure 2This is a typical topology diagram of the self-powered operation and maintenance system for offshore wind farms based on grid-type wind turbines, according to the present invention. The components are: 1-energy storage battery, 2-bidirectional DC / DC converter, 3-wind turbine generator, 4-wind turbine-side converter, 5-wind turbine DC bus, 6-wind turbine grid-side converter, 7-wind turbine operation and maintenance self-consumption load, 8-wind turbine step-up transformer, 9-wind turbine circuit breaker, 10-offshore AC bus, 11-offshore substation, 12-wind farm transmission cable, and 13-onshore control center circuit breaker.

[0031] Figure 3 This is a schematic diagram of a specific example system for the wind turbine grid-side converter control method of the present invention. The modules are: 14-voltage reference value calculation module, 15-Park conversion module, 16-voltage outer loop controller, 17-current inner loop controller, 18-Park inverse conversion module, and 19-modulation module.

[0032] Figure 4 This is a schematic diagram of a specific example system for the wind turbine-side converter control method of the present invention. In the diagram, 20 is the rotor position observer, 21 is the Park converter module, 22 is the power outer loop controller, 23 is the current inner loop controller, 24 is the Park inverse converter module, and 25 is the modulation module. Detailed Implementation

[0033] To describe the present invention in more detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] In this embodiment of the invention, the self-powered operation and maintenance system for offshore wind farms based on grid-type wind turbines is as follows: Figure 2 As shown, it includes an energy storage battery 1, a bidirectional DC / DC converter 2, a wind turbine generator 3, a wind turbine generator-side converter 4, a wind turbine DC bus 5, a wind turbine grid-side converter 6, a wind turbine step-up transformer 8, a wind turbine circuit breaker 9, an offshore AC bus 10, an offshore substation 11, a wind farm transmission submarine cable 12, and an onshore control center circuit breaker 13.

[0035] In this embodiment of the invention, the energy storage battery 1 is connected to the wind turbine DC bus 5, which serves as the self-use power supply for wind farm operation and maintenance, through a bidirectional DC / DC converter 2; the self-use power load 7 for wind turbine operation and maintenance is connected to the outlet of the wind turbine grid-side converter 6 for power extraction.

[0036] The wind turbine is connected to the offshore AC grid via the turbine-side converter 4, DC bus 5, and grid-side converter 6. The voltage is then stepped up to the offshore AC bus level by the turbine step-up transformer 8, and connected to the offshore AC bus 10 via the turbine circuit breaker 9. Multiple offshore wind turbines converge on the offshore AC bus and are stepped up to the onshore AC bus level by the offshore substation 11. The offshore wind power transmission cable 12 and the onshore control center circuit breaker 13 connect the offshore wind farm to the onshore AC grid. During the off-grid operation of the wind farm, the onshore control center circuit breaker 13 is in the open state, and the offshore wind farm is not connected to the onshore AC grid.

[0037] In this embodiment of the invention, the specific process of starting up the self-powered system for operation and maintenance of an offshore wind farm based on a grid-type wind turbine is as follows: Figure 1 As shown.

[0038] The first step is to start the energy storage battery 1 and the bidirectional DC / DC converter 2, and adjust the DC bus voltage of the wind turbine to the rated value through the control strategy of the bidirectional DC / DC converter. Among them, the bidirectional DC / DC converter 2 adopts a constant DC bus voltage control strategy, and the DC bus voltage reference value is set to the rated value of the DC side bus voltage of the energy storage grid-connected inverter.

[0039] The second step is to start the grid-side converter 6 of the wind turbines, which serves as the self-consumption power source for the wind farm's operation and maintenance, and close the wind turbine circuit breaker 9. Through the grid-type virtual synchronous machine control strategy of the wind turbine grid-side converter 6, the offshore AC grid voltage is established. In this embodiment of the invention, the grid-type virtual synchronous machine control strategy adopted by the wind turbine grid-side converter 6 has the following control system... Figure 3 As shown, it includes: voltage reference value calculation module 14, Park transformation module 15, voltage outer loop controller 16, current inner loop controller 17, Park inverse transformation module 18, and modulation module 19;

[0040] In the voltage reference value calculation module 14, the reference phase θ is calculated according to the following method. g :

[0041] θ g (k+1)=∫ω g (k+1)dt

[0042]

[0043] Where, θ g (k+1) is the reference phase for the next sampling period, ω g (k+1) is the angular frequency of the next sampling period, ω g (k) is the angular frequency of this sampling period, ω n P is the rated angular frequency. gref P is the active power reference value. g(k) represents the active power in this sampling period, J represents the virtual rotor moment of inertia, and D... p This is the active damping coefficient.

[0044] The d-axis voltage reference value u is calculated using the following method. gdref :

[0045]

[0046] Among them, u gdref (k+1) is the d-axis voltage reference value for the next sampling period, |U g (k)| represents the voltage amplitude during this sampling period, U ref Q is the reference value for voltage amplitude. gref Q is the reactive power reference value. g (k) represents the reactive power in this sampling period, K is the virtual excitation coefficient, and D q This is the reactive damping coefficient.

[0047] The voltage outer loop controller 16 is implemented as follows:

[0048]

[0049]

[0050] Wherein: F PI1 (s) is the transfer function of the PI controller, k p1 k is the proportionality coefficient. i1 Let i be the integral coefficient. gdref i gqref Corresponding to the current vector I gdqref d-axis, q-axis components, u gdref ,u gqref Corresponding to the voltage vector reference value U gdqref d-axis, q-axis components, u gd ,u gq Corresponding to the voltage vector reference value U gdq The d-axis and q-axis components.

[0051] The implementation method of the current inner loop controller 17 is as follows:

[0052]

[0053]

[0054] Wherein: F PI2 (s) is the transfer function of the PI controller, k p2 k is the proportionality coefficient. i2 U is the integral coefficient. vdref ,u vqref Corresponding to voltage vector Uvdqref d-axis, q-axis components, u gd ,u gq Corresponding to voltage vector U gdq d-axis and q-axis components, i gd i gq Corresponding to the current vector I gdq d-axis and q-axis components, ω g L is the angular frequency of the grid voltage. g This is a filter inductor.

[0055] The third step is to use the energy storage battery 1 to supply power to the wind turbine's self-use load 7 through the bidirectional DC / DC converter 2 and the wind turbine grid-side converter 6 after the offshore AC grid voltage is established.

[0056] The fourth step involves starting the wind turbine-side converter 4 and wind turbine generator 3, which serve as the wind farm's self-consumption power source. By adjusting the active power reference value of the converter 4, the output active power of the wind turbine is gradually increased to a first set value, which is determined based on the self-consumption power load of a single wind turbine. The converter 4 employs a constant active and reactive power control strategy, and its control system is as follows: Figure 4 As shown, it includes: rotor position observer 20, Park transformation module 21, power outer loop controller 22, current inner loop controller 23, Park inverse transformation module 24, and modulation module 25.

[0057] The power outer loop controller 22 is implemented as follows:

[0058]

[0059]

[0060] Wherein: F PI1 (s) is the transfer function of the PI controller, k p1 k is the proportionality coefficient. i1 Let i be the integral coefficient. sdref i sqref Corresponding to the current vector I sdqref d-axis and q-axis components, P sref P is the active power reference value. s For active power, Q sref Q is the reactive power reference value. s This refers to reactive power.

[0061] The implementation method of the current inner loop controller 23 is as follows:

[0062]

[0063]

[0064] Wherein: F PI4 (s) is the transfer function of the PI controller, k p4 k is the proportionality coefficient. i4 U is the integral coefficient. sdref ,u sqref Corresponding to voltage vector U sdqref d-axis and q-axis components, i sd i sq Corresponding to the current vector I sdq d-axis and q-axis components, ω r L is the rotor angular frequency. s Ψ represents the stator inductance of the wind turbine, and Ψ represents the rotor permanent magnet flux linkage.

[0065] The fifth step involves closing the circuit breakers of the other wind turbines in the wind farm one by one to supply power to the self-powered operation and maintenance system of the other wind turbines. The power reference value of the turbine-side converter, which serves as the self-powered operation and maintenance power supply for the wind farm, is gradually increased, and the output active power of the wind turbines is adjusted to the second set value. The second set value is given based on the self-powered operation and maintenance power load of all wind turbines in the wind farm.

[0066] Because the grid-side converter of the wind turbine adopts a grid-type virtual synchronous machine control strategy, and the bidirectional DC / DC converter adopts a constant DC bus voltage control strategy, when the active power output of the wind turbine matches the self-powered load of the wind farm operation and maintenance, the power supply of the entire system will be entirely provided by the wind turbine. The energy storage system only serves as a regulating power source to smooth out wind power output fluctuations and maintain a constant DC bus voltage of the wind turbine. After the system startup process is completed, the self-powered system for off-grid operation and maintenance of the entire offshore wind farm can operate stably for a long period of time.

[0067] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to the above embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. A method for starting up an offshore wind farm's self-powered operation and maintenance system based on grid-connected wind turbines, characterized in that... The offshore wind farm operation and maintenance self-power supply system based on grid-connected wind turbines includes: energy storage batteries, bidirectional DC / DC converters, wind turbines, turbine-side converters, turbine DC buses, turbine grid-side converters, turbine step-up transformers, turbine circuit breakers, offshore AC buses, offshore substations, wind farm transmission cables, and onshore control center circuit breakers. The wind turbines are connected to the offshore AC grid via turbine-side converters, DC buses, and grid-side converters. The voltage is then stepped up to the offshore AC bus level by the turbine step-up transformers and connected to the offshore AC bus via the turbine circuit breakers. Multiple offshore wind turbines converge on the offshore AC bus and are then stepped up to the onshore AC bus level by the offshore substations. Finally, they are connected to the onshore AC grid via offshore transmission cables and onshore control center circuit breakers. During off-grid operation, the onshore control center circuit breakers are in the open state, and the offshore wind farm is not connected to the onshore AC grid. During the off-grid operation of the offshore wind farm based on grid-connected wind turbines, one wind turbine is selected as the self-use power source for wind farm operation and maintenance and connected to the grid for power generation. The converters of the remaining wind turbines are locked, and only the self-use power system for operation and maintenance is in operation. Only the wind turbines used as the self-use power source for wind farm operation and maintenance need to be equipped with energy storage batteries and bidirectional DC / DC converters. The method for starting up the self-powered operation and maintenance system of offshore wind farms based on grid-connected wind turbines is characterized by the following: The system startup process begins by starting the energy storage battery and the bidirectional DC / DC converter. The control strategy of the bidirectional DC / DC converter is used to adjust the DC bus voltage of the wind turbine to the rated value. Start the grid-side converter of the wind turbine that serves as the self-use power source for the wind farm's operation and maintenance, close the wind turbine circuit breaker, and establish the offshore AC grid voltage through the grid-type virtual synchronous machine control strategy of the wind turbine grid-side converter; After the offshore AC grid voltage is established, the energy storage battery supplies power to the wind turbine's self-use power system through a bidirectional DC / DC converter and a wind turbine grid-side converter. Start the wind turbine-side converter and wind turbine generator, which serve as the self-use power source for the wind farm's operation and maintenance. By adjusting the active power reference value of the converter, gradually increase the output active power of the wind turbine to a first set value. The first set value is given based on the self-use power load of a single wind turbine. The circuit breakers of other wind turbines in the wind farm are closed one by one to supply power to the self-powered operation and maintenance system of other wind turbines. The power reference value of the wind turbine converter on the turbine side as the power source is gradually increased, and the output active power of the wind turbine is adjusted to the second set value. The second set value is given according to the self-powered operation and maintenance load power of all wind turbines in the wind farm. When the active power output of the wind turbine matches the self-powered load of the wind farm operation and maintenance, the power supply of the entire system will be entirely provided by the wind turbine, and the energy storage system will only serve as a regulating power source to smooth out fluctuations in wind power output and maintain a constant DC bus voltage of the wind turbine.

2. The start-up method for the self-powered operation and maintenance system of an offshore wind farm based on a grid-type wind turbine as described in claim 1, characterized in that: The bidirectional DC / DC converter adopts a constant DC bus voltage control strategy, which is responsible for establishing the DC bus voltage of the wind turbine during system startup and maintaining the stability of the DC bus voltage of the wind turbine during operation. The constant DC bus voltage control strategy of the bidirectional DC / DC converter is mainly realized through the outer loop of DC bus voltage control and the inner loop of current control.

3. The start-up method for the self-powered operation and maintenance system of an offshore wind farm based on a grid-type wind turbine as described in claim 1, characterized in that: The wind turbine grid-side converter, which serves as the self-use power source for wind farm operation and maintenance, adopts a grid-type virtual synchronous machine control strategy. It is responsible for establishing the offshore AC grid voltage during system startup and maintaining the stability of the AC grid during operation. The grid-type virtual synchronous machine control strategy is implemented through a voltage reference value calculation module, a voltage outer loop controller, and a current inner loop controller. Among them, the voltage reference value calculation module provides voltage and frequency support for the self-use power supply system by simulating the mechanical equations and excitation equations of a traditional synchronous generator. In the voltage reference value calculation module, the reference phase θ is calculated according to the following method. g : Where, θ g (k+1) is the reference phase for the next sampling period, ω g (k+1) is the angular frequency of the next sampling period, ω g (k) is the angular frequency of this sampling period, ω n P is the rated angular frequency. gref P is the active power reference value. g (k) represents the active power in this sampling period, J represents the virtual rotor moment of inertia, and D... p This is the active damping coefficient; In the voltage reference value calculation module, the d-axis voltage reference value u is calculated according to the following method. gdref : Among them, u gdref (k+1) is the d-axis voltage reference value for the next sampling period, |U g (k)| represents the voltage amplitude during this sampling period, U ref Q is the reference value for voltage amplitude. gref Q is the reactive power reference value. g (k) represents the reactive power in this sampling period, K is the virtual excitation coefficient, and D q This is the reactive damping coefficient.

4. The start-up method for the self-powered operation and maintenance system of an offshore wind farm based on a grid-type wind turbine as described in claim 1, characterized in that: The wind turbine-side converter, which serves as the self-consumption power supply for wind farm operation and maintenance, adopts a constant active and reactive power control strategy. Its active power command is given as a first set value and a second set value at different stages of the system startup process. The first set value is given based on the self-consumption power load of a single wind turbine, and the second set value is given based on the sum of the self-consumption power load of all wind turbines. It is responsible for providing active power supply for wind turbine operation and maintenance during off-grid operation. The control strategy of the wind turbine-side converter is implemented through a power outer loop controller and a current inner loop controller.

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