AC-DC coupling energy storage wind turbine generator and active support control method thereof
By constructing an AC/DC coupled energy storage system in wind turbine units and using the energy storage unit converter to adjust the control strategy, the problem that existing wind turbine units cannot actively respond to voltage and frequency changes has been solved. This has enabled coordinated control of active and reactive power, reduced retrofit costs, and improved flexibility.
Patent Information
- Application Number
- CN202511054547.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-11-14
AI Technical Summary
Existing doubly-fed or full-power conversion wind turbines lack the ability to actively respond to changes in system voltage and frequency, cannot achieve coordinated active and reactive power control, and have high retrofit costs.
An AC/DC coupled energy storage system is constructed in the wind turbine. By setting the energy storage unit converter between the turbine-side and grid-side converters, and combining DC/AC and DC/DC converters, the AC side signals are collected to adjust the control strategy, thereby achieving coordinated control of active and reactive power.
It enables wind turbines to actively respond to system voltage and frequency, reduces retrofit costs, and improves the flexibility of active support performance, making it suitable for doubly-fed and full-power conversion wind turbines.
Smart Images
Figure CN120955747A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of new energy technology, and in particular to a wind turbine generator with AC / DC coupled energy storage and its active support control method. Background Technology
[0002] New power systems primarily powered by renewable energy require renewable energy generators to possess proactive power system support capabilities, namely, the ability to actively respond to changes in system voltage and frequency. Due to the uncertainty of wind power and the control characteristics of wind power converters, existing doubly-fed or full-power converter wind turbines lack the responsiveness to system frequency and voltage similar to synchronous generators. Taking a full-power converter wind turbine as an example, because it needs to maintain the DC bus voltage, the grid-side converter has only one degree of control freedom, making it impossible to coordinate active and reactive power control functions. At the same time, the turbine-side converter is limited by the unit's speed range and input power, and cannot provide stable and continuous active power support. Summary of the Invention
[0003] This application aims to at least partially address one of the technical problems in the related art.
[0004] Therefore, the first objective of this application is to propose an active support control method for wind turbines with AC / DC coupled energy storage. This method does not change the existing grid-side and turbine-side converter control strategies of grid-connected turbines, reduces retrofit costs, and allows for flexible configuration of energy storage units based on the active support capability target of the entire turbine. It enables coordinated control of the active and reactive power of the entire turbine, has excellent active support performance and high flexibility, and is suitable for doubly-fed and full-power conversion wind turbines.
[0005] The second objective of this application is to propose a wind turbine generator with AC / DC coupled energy storage.
[0006] To achieve the above objectives, the first aspect of this application proposes an active support control method for wind turbine generators with AC / DC coupled energy storage, comprising:
[0007] An energy storage unit converter is constructed and installed between the wind turbine generator-side converter RSC and the grid-side converter GSC. The wind turbine is a doubly fed or full-power converter type wind turbine. The energy storage unit converter has a two-stage structure, including a DC / AC section PCS and a DC / DC section FSBB. The output port of FSBB is connected to the DC bus of the wind turbine, and the output port of PCS is connected to the AC bus of the wind turbine. The PCS and FSBB share a common DC input terminal connected to the battery pack.
[0008] The control strategy of the energy storage unit converter is set. By controlling the opening and closing status of the circuit breakers at each port of the energy storage converter and the switching of the control mode of the FSBB, the wind turbine can be assisted to achieve different control scenarios. The three-phase voltage and current signals of the AC side of the unit are collected, and the modulation signals generated by the calculation based on the collected data are sent to the FSBB and PCS sections respectively to achieve active support for the wind turbine.
[0009] To achieve the above objectives, a second aspect of the present invention provides a wind turbine with AC / DC coupled energy storage, which implements the above-mentioned active support control method for wind turbines with AC / DC coupled energy storage.
[0010] The AC / DC coupled energy storage wind turbine and its active support control method in this application embodiment acquires and calculates AC side signals, reuses the existing converter of the wind turbine, and combines a bidirectional DC / DC converter control strategy to enable the wind turbine to have the expected active support capability. This application does not change the existing grid-side and turbine-side converter control strategies of grid-connected turbines, reducing retrofit costs. At the same time, it flexibly configures energy storage units according to the active support capability target of the whole machine, and can realize the coordinated control of active and reactive power of the whole machine. It has excellent active support performance and high flexibility, and is suitable for doubly-fed and full-power converter wind turbines.
[0011] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description
[0012] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:
[0013] Figure 1 This is a flowchart illustrating an active support control method for AC / DC coupled energy storage wind turbine provided in Embodiment 1 of this application.
[0014] Figure 2 This is a schematic diagram illustrating the application of a doubly-fed wind turbine in an embodiment of this application.
[0015] Figure 3 This is a schematic diagram illustrating the application of a full-power conversion type wind turbine in an embodiment of this application. Detailed Implementation
[0016] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0017] The following description, with reference to the accompanying drawings, describes an AC / DC coupled energy storage wind turbine generator and its active support control method according to embodiments of this application.
[0018] Figure 1 This is a flowchart illustrating an active support control method for AC / DC coupled energy storage wind turbine provided in Embodiment 1 of this application.
[0019] like Figure 1 As shown, the active support control method for AC / DC coupled energy storage wind turbine units includes the following steps:
[0020] Step 101: Construct an energy storage unit converter, which is set between the wind turbine generator-side converter RSC and the grid-side converter GSC. The wind turbine is a doubly fed or full-power converter type wind turbine. The energy storage unit converter has a two-stage structure, including a DC / AC section PCS and a DC / DC section FSBB. The output port of FSBB is connected to the DC bus of the wind turbine, and the output port of PCS is connected to the AC bus of the wind turbine. The PCS and FSBB share a common DC input terminal connected to the battery pack.
[0021] Specifically, Figure 2 This is a schematic diagram illustrating the application of the doubly-fed wind turbine in this embodiment. Figure 3 This is a schematic diagram of a full-power conversion wind turbine application, such as... Figure 2 , Figure 3 As shown, the energy storage unit converter has a two-stage structure, including a DC / AC section (using a three-phase full-bridge two-level or three-level structure, abbreviated as PCS) and a DC / DC section (using a four-switch buck-boost topology, abbreviated as FSBB). The output port of the FSBB section is connected to the DC bus of the doubly-fed or full-power converter wind turbine, and the output port of the PCS is connected to the AC bus of the doubly-fed or full-power converter wind turbine. The PCS section and the FSBB share a common DC input terminal for connection to the battery pack.
[0022] Step 102: Set the control strategy for the energy storage unit converter. By controlling the opening and closing status of the circuit breakers at each port of the energy storage converter and the switching of the FSBB control mode, assist the wind turbine in achieving different control scenarios. Collect the three-phase voltage and current signals on the AC side of the unit, and send the modulated signals generated based on the collected data to the FSBB and PCS sections respectively to achieve active support for the wind turbine.
[0023] Specifically, the three-phase voltage and current signals on the AC side of the generator unit are collected, and after calculation, the modulated signals are sent to the FSBB and PCS sections respectively to actively support the target requirements. The control strategy includes unit main control, reactive power coordination control, PCS active / reactive power control, and FSBB DC voltage / current control.
[0024] Specifically, based on the opening and closing status of the short circuits at each AC / DC port of the energy storage converter (O for off, I for closed), this embodiment is applicable to assisting wind turbines in realizing multiple functional scenarios. The FSBB part switches between DC voltage or current control modes according to the control scenario, as shown in Table 1.
[0025] Table 1 Control Function Scenarios
[0026]
[0027] Specifically, in scenario 6, the unit's main control strategy is: based on the terminal voltage and current, the real-time output power P of the computer group is calculated. t The system frequency f is calculated based on the three-phase voltage signal. t Transient voltage amplitude U t To ensure the accuracy of state estimation, the three-phase voltage acquisition frequency is no less than 3.2kHz. Furthermore, the computer group sets real-time active and reactive power adjustment targets. The real-time active power adjustment target is calculated based on frequency deviation and frequency change rate:
[0028]
[0029] Where: XP aim0 : Adjustment of target active power output of wind turbine generators, MW, P t0 Calculate the frequency f t Beyond the set dead time, the active power output at the machine terminal, MW, Xf: system frequency deviation, Xf <f t ,f n f n System rated frequency, 50Hz, P n : The sum of the rated power of the wind turbine and the rated power of the PCS (Power Storage System), in MW; δ%: Setting the primary frequency regulation droop rate, in T. J : Set the inertia time constant, in seconds. System frequency change rate.
[0030] The real-time reactive power regulation target is calculated based on the transient voltage amplitude:
[0031]
[0032] In the formula, Q aim0 Target reactive power output of wind turbine generators, MVar, Q t0 Calculate the active power output, MVar, and U at the generator terminal when the transient voltage amplitude exceeds the set dead zone. t Transient voltage amplitude at the generator terminal, per unit value, U n Terminal voltage rated amplitude, per unit value, U max Maximum permissible amplitude of transient voltage at the machine terminal, per unit value, U minMinimum allowable amplitude of transient voltage at the machine terminal, per unit value, Q. GSC Reactive power limits of wind turbine generator-side converters, MVar, Q PCS Reactive power limit of the PCS section of the energy storage converter, MVar.
[0033] The reactive power coordination control strategy is as follows: The reactive power regulation target is allocated to the generator-side converter (GSC) and the energy storage converter (PCS) portion. The allocation algorithm is as follows:
[0034]
[0035] In the formula, Q GSC_ref The reference power for reactive power modulation of the grid-side converter of the wind turbine is MVar, Q. PCS_ref MVar is the reference power for reactive power modulation in the PCS section of the energy storage converter.
[0036] The active power coordination control strategy is as follows: Active power regulation targets are allocated to the PCS and FSBB sections of the energy storage converter. Taking discharge as an example, the allocation algorithm is as follows:
[0037]
[0038] In the formula: P FSBB_ref Reference power modulated by the FSBB section of the energy storage converter, in MW and U. dc DC bus voltage of wind turbine, U dc_max Maximum allowable DC bus voltage of wind turbine generator set, kV, U dc_min Minimum allowable DC bus voltage of wind turbine generator set, kV, U b Battery pack voltage, kV, I b_max : Maximum allowable discharge current of the battery pack, kV.
[0039]
[0040] In the formula, P PCS_ref The reference power for active power modulation in the PCS section of the energy storage converter, in MW, I in The input port current of the energy storage converter FSBB is kA.
[0041] To achieve the above embodiments, the present invention also proposes an AC / DC coupled energy storage wind turbine, which implements the above-mentioned active support control method for AC / DC coupled energy storage wind turbine.
[0042] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0044] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.
[0045] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.
[0046] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.
[0047] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.
[0048] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.
[0049] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.
Claims
1. A method for active support control of wind turbine generators with AC / DC coupled energy storage, characterized in that, include: An energy storage unit converter is constructed, which is located between the wind turbine generator-side converter RSC and the grid-side converter GSC. The wind turbine is a doubly fed or full-power converter type wind turbine. The energy storage unit converter has a two-stage structure, including a DC / AC section PCS and a DC / DC section FSBB. The output port of FSBB is connected to the DC bus of the wind turbine, and the output port of PCS is connected to the AC bus of the wind turbine. The PCS and FSBB share a common DC input terminal connected to the battery pack. The control strategy of the energy storage unit converter is set. By controlling the opening and closing status of the circuit breakers at each port of the energy storage unit converter and the switching of the control mode of the FSBB, the wind turbine can be assisted to achieve different control scenarios. The three-phase voltage and current signals of the AC side of the unit are collected, and the modulation signals generated by the calculation based on the collected data are sent to the FSBB and PCS sections respectively to achieve active support for the wind turbine.
2. The method as described in claim 1, characterized in that, The control scenarios include: transient voltage support and rapid frequency response when not coordinated with the unit, transient voltage support, fault ride-through, rapid frequency response, fault ride-through and unit self-start, transient voltage support and rapid frequency response.
3. The method as described in claim 2, characterized in that, The FSBB output port is port S1, the PCS part shares a DC input port with the FSBB, port S2, the PCS part output port is port D1, and the FSBB control mode is DC voltage or current control mode.
4. The method as described in claim 3, characterized in that, The control strategies for transient voltage support and rapid frequency response when not coordinated with the unit are as follows: S1 port off, S2 port closed, D1 port closed, FSBB not enabled; the control strategy for transient voltage support is as follows: S1 port closed, S2 port off, D1 port closed, FSBB control mode switched to DC voltage control mode; the control strategy for fault ride-through is as follows: S1 port closed, S2 port closed, D1 port off, FSBB control mode switched to DC voltage control mode; the control strategy for rapid frequency response is as follows: S1 port closed, S2 port closed, D1 port off, FSBB control mode switched to DC voltage control mode; the control strategy for fault ride-through and unit self-start is as follows: S1 port closed, S2 port closed, D1 port closed, FSBB control mode switched to DC voltage control mode; the control strategies for transient voltage support and rapid frequency response are as follows: S1 port closed, S2 port closed, D1 port closed, FSBB control mode switched to DC voltage control mode.
5. The method as described in claim 4, characterized in that, The control strategy also includes: In scenarios involving transient voltage support and rapid frequency response, the system frequency and transient voltage amplitude are calculated based on the real-time output power of the computer group using the collected terminal voltage and current data, and the three-phase voltage signals. The active power adjustment target of the computer group is adjusted in real time according to the frequency deviation and frequency change rate, and the reactive power adjustment target of the computer group is adjusted in real time according to the pause voltage amplitude. The active real-time adjustment target is assigned to the PCS section and the FSBB section; The reactive power real-time adjustment target is assigned to the machine-side converter GSC and PCS sections.
6. The method as described in claim 5, characterized in that, The real-time target for active power regulation is: Among them, XP aim0 Xf represents the adjustment of the target active power output of the wind turbine, and f represents the system frequency deviation. n T is the system's rated frequency. J The set inertia time constant, P is the rate of change of the system frequency. n It is the sum of the rated power of the wind turbine and the rated power of the PCS part of the energy storage unit, and δ% is the set primary frequency regulation droop rate.
7. The method as described in claim 5, characterized in that, The target for real-time reactive power adjustment is: Among them, Q aim0 The target reactive power output of the wind turbine is Q. t0 To pause the active power output of the generator terminal when the voltage amplitude exceeds the set dead time, U t U is the amplitude of the transient voltage at the machine terminal. n U is the rated amplitude of the terminal voltage. max U is the maximum permissible amplitude of the transient voltage at the machine terminal. min Q is the minimum allowable amplitude of the transient voltage at the machine terminal. GSC Q is the reactive power limit of the wind turbine generator-side converter. PCS This refers to the reactive power limit of the PCS section of the energy storage converter.
8. The method as described in claim 5, characterized in that, When allocating the active power regulation target to the PCS and FSBB sections of the energy storage converter, the allocation method is as follows under the discharge scenario: Among them, P FSBB_ref P is the reference power for partial modulation of the FSBB. PCS_ref U is the reference power for active power modulation in the PCS section. dc_min U dc_max U represents the minimum and maximum allowable values of the DC bus voltage for wind turbine generators. b I is the battery pack voltage. b_max I is the maximum allowable discharge current of the battery pack. in For the FSBB input port current of the energy storage converter, XP aim0 This refers to the adjustment amount of the target active power output of the wind turbine.
9. The method as described in claim 5, characterized in that, When allocating reactive power regulation targets to the generator-side converter (GSC) and the energy storage converter (PCS), the allocation method is as follows: Among them, Q GSC_ref Q is the reference power for reactive power modulation of the grid-side converter of the wind turbine. PCs_ref Q is the reference power for reactive power modulation in the PCS section of the energy storage converter. GSC Q is the GSC reactive power limit for the wind turbine generator-side converter. PCS For the reactive power limit of the PCS section, Q aim0 The reactive power output is for the target wind turbine unit.
10. A wind turbine generator with AC / DC coupling energy storage, characterized in that, The wind turbine implements the active support control method for AC / DC coupled energy storage wind turbine as described in claim 1.