Standby primary frequency modulation control system for rotation inertia of direct-driven fan
By introducing back-to-back dual PWM converters and phase-locked loops into direct-drive wind turbines, combined with spinning reserve capacity and curtailment frequency regulation, the problem of inertial response that direct-drive wind turbine generators cannot provide was solved, achieving rapid response and stability to grid frequency and improving system frequency stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-13
- Publication Date
- 2026-03-13
AI Technical Summary
Direct-drive wind turbine generators, being decoupled from the grid, cannot naturally provide inertial response and primary frequency regulation support, resulting in decreased system frequency stability. Furthermore, the output power of wind turbine generators is often at its peak, making it impossible to regulate power output through active power reserves and effectively cope with frequency disturbances.
A back-to-back dual PWM converter is connected to the permanent magnet wind turbine generator set. By rotating reserve capacity and curtailment frequency regulation, a fast response to the grid frequency is achieved. Power regulation is performed using the generator-side converter and the grid-side converter. The active power adjustment and rotating reserve capacity are calculated. A phase-locked loop is added to detect the grid frequency and phase, so as to realize the primary frequency regulation control of the rotating inertia reserve of the direct-drive wind turbine.
Without adding energy storage equipment, the wind turbine's ability to support the frequency stability of the power system is improved, enabling it to respond quickly to frequency changes, maintain system frequency stability, and enhance the system's anti-interference capability.
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Figure CN121663542A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of anomaly analysis technology, and in particular to a primary frequency regulation control system for the rotational inertia backup of a direct-drive fan. Background Technology
[0002] Direct-drive wind power generation, as the most important renewable energy source, often experiences frequency fluctuations due to mismatches with electricity loads. The conventional approach is to smooth out these fluctuations through energy storage, but this overlooks the inherent spinning reserve capacity and frequency regulation capabilities of wind turbines themselves. According to the International Energy Agency (IEA), global wind power capacity has exceeded 900 GW and is expected to continue its rapid growth in the coming years. If wind turbines lack primary frequency regulation capabilities, a significant amount of energy storage and frequency regulation equipment will be needed. In some regions with high wind power penetration, such as parts of Denmark and Germany, wind power output fluctuations have posed a real threat to the frequency stability of local power systems, with frequency deviations exceeding permissible limits, affecting the safe and reliable operation of the power system. There is an urgent need for a method that, without adding energy storage, can rapidly respond to frequency changes and participate in primary frequency regulation to maintain system frequency stability through the inertia of synchronous generators and the redundancy capacity of converters. Because wind turbine generators (i.e., permanent magnet wind turbine generators) are connected to the power grid through power electronic converters, their operation differs from that of traditional synchronous generators. During normal operation, the inertia between the wind turbine generator and the power grid is decoupled, preventing it from naturally providing inertial response and primary frequency regulation support to the system like a synchronous generator. Therefore, researching technologies for wind turbine generators to participate in primary frequency regulation and improving their ability to support power system frequency stability has become an important issue in the current power sector.
[0003] GB / T 40595-2021 stipulates that the primary frequency regulation dead zone of a wind farm should be greater than ±0.067Hz, and the over-frequency dead zone and under-frequency dead zone should be independently set, with a recommended value of ±0.1Hz. The lag time of active power in the primary frequency regulation of a wind farm should be less than 2s, and the adjustment time should be less than 15s. When the active power output of the wind turbine exceeds 20% of the rated power, continuous and smooth adjustment of active power should be achieved. When the system frequency decreases, the upper limit of the active power change should preferably be 6% to 10% of the rated power; when the system frequency increases, the upper limit of the active power change should preferably be 10% to 20% of the rated power. With the large-scale grid connection of wind power, the two major tasks that urgently need to be addressed regarding power system frequency stability are:
[0004] 1. Wind turbines are connected to the grid through a large number of power electronic devices, which leads to the decoupling of motor speed and frequency, reduces the system's equivalent inertia, and greatly reduces the system's inertia response capability. This weakens the system's anti-interference capability when facing frequency disturbances.
[0005] 2. To improve wind energy utilization and economic efficiency, current wind turbines generally employ maximum power point tracking (MPPT), ensuring that the generating equipment always operates at its maximum output power. This results in the generating equipment's output power consistently being at its "peak." However, for the entire wind power system, this reduces or even eliminates the active power reserve. When faced with frequency disturbances, it becomes impossible to adjust power output through active power reserve, and consequently, it becomes impossible to regulate the frequency by adjusting the output. Summary of the Invention
[0006] The purpose of this invention is to provide a primary frequency regulation control system for the rotational inertia backup of a direct-drive fan, so as to solve one or more of the problems mentioned in the background art.
[0007] To achieve the above objectives, the present invention provides the following technical solution:
[0008] A direct-drive wind turbine rotating inertia reserve primary frequency regulation control system includes a back-to-back dual PWM converter connected to the permanent magnet wind turbine generator and the power grid. The system addresses frequency drops at the grid connection point by increasing the rotating reserve capacity and addresses frequency rises at the grid connection point by regulating the frequency of wind curtailment. This matches randomly changing wind power to the constantly fluctuating power grid, achieving demand-side response.
[0009] In some embodiments, the permanent magnet wind turbine generator set includes a wind turbine drive mechanism and a permanent magnet synchronous generator.
[0010] In some embodiments, an encoder is installed on the fan rotor shaft in the fan drive mechanism. The encoder is used to detect the position and wind speed of the fan rotor so as to enable power regulation of the machine-side converter in the back-to-back dual PWM converter.
[0011] In some embodiments, the back-to-back dual PWM converter includes a machine-side converter and a grid-side converter, wherein
[0012] The generator-side converter regulates power by rotating reserve capacity and wind curtailment frequency regulation, and determines the power generation by wind speed and grid frequency information, and controls the electromagnetic torque.
[0013] The grid-side converter operates by stabilizing the DC bus voltage, converting the frequency fluctuations on the AC side into the voltage fluctuations on the DC side, which serves as a channel for power transfer.
[0014] In some implementations, the generator-side converter regulates frequency by controlling active power. Specifically, when the grid frequency is greater than the rated frequency, the permanent magnet wind turbine generator reduces active power by curtailing wind power; when the grid frequency is less than the rated frequency, the spinning reserve capacity increases active power.
[0015] In some implementations...
[0016] The formula for calculating the active power of the primary frequency control system for the standby moment of inertia of a direct-drive fan is as follows:
[0017]
[0018] The formula for calculating the adjustment of active power is:
[0019] ΔP=-Δf·K d ,
[0020] The formula for calculating spinning reserve capacity is as follows:
[0021]
[0022] In the above formula The active power of the primary frequency control system is used to reserve the rotational inertia of the direct-drive wind turbine. ΔP is the adjustment amount of the active power. reserve For spinning reserve capacity, P ref K represents the active power in maximum power point tracking mode. d ω is the virtual droop coefficient, J is the rotational inertia of the direct-drive fan, and ω is the angular velocity.
[0023] In some implementations, the control parameters of both the machine-side converter and the grid-side converter are calibrated by amplitude normalization. The control parameters of the machine-side converter include machine-side current and machine-side power, while the control parameters of the grid-side converter include grid-side voltage and current. This configuration simplifies the execution process of the primary frequency regulation control system for the direct-drive wind turbine's rotational inertia backup.
[0024] In some implementations, the primary frequency control system for the rotational inertia backup of the direct-drive wind turbine also includes a phase-locked loop (PLL), which detects the grid frequency and phase and adjusts the power of the machine-side converter in the back-to-back dual PWM converter through shared control signals. Attached Figure Description
[0025] Figure 1 This is a topology diagram of a primary frequency regulation control system for backup rotational inertia of a direct-drive fan provided in some embodiments of the present invention;
[0026] Figure 2 For some embodiments of the present invention, the parameters of the primary frequency regulation of the backup primary frequency regulation control system for the rotational inertia of the direct-drive fan are provided.
[0027] Figure 3 The diagram illustrates the standby primary frequency regulation response of the rotating inertia of a direct-drive wind turbine when the grid frequency fluctuates between 49.8 Hz and 50.2 Hz, according to some embodiments of the present invention. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0029] Figure 1 This invention illustrates a direct-drive wind turbine rotating inertia reserve primary frequency regulation control system, comprising a back-to-back dual PWM converter connected to a permanent magnet wind turbine generator set and the power grid. The system addresses grid connection point frequency drops by increasing the rotating reserve capacity (a portion of the existing permanent magnet wind turbine generator set's reserve capacity locked by software during normal operation, which is rapidly released when the grid frequency drops momentarily). The direct-drive wind turbine rotating inertia reserve primary frequency regulation control system increases the grid connection point frequency through wind curtailment frequency regulation (wind curtailment frequency regulation aims to stabilize the grid frequency; when the grid frequency rises, the permanent magnet wind turbine generator set must operate below the maximum power point tracking curve).
[0030] The permanent magnet wind turbine generator set includes a wind turbine drive mechanism and a permanent magnet synchronous generator. An encoder can be added to the wind turbine rotor shaft in the wind turbine drive mechanism. The encoder can detect the position and wind speed of the wind turbine rotor so as to adjust the power of the generator-side converter in the back-to-back dual PWM converter.
[0031] The back-to-back dual PWM converter includes a machine-side converter and a grid-side converter.
[0032] The design of the back-to-back dual PWM converter decouples the generation frequency and the grid frequency, so that when the grid frequency fluctuates, the permanent magnet wind turbine generator and converter can respond to the change in power efficiency in a timely manner, supporting the stability of the grid connection point frequency.
[0033] Grid-side converters operate by stabilizing the DC bus voltage, converting AC-side frequency fluctuations into DC-side voltage fluctuations, thus playing a role in power transfer. Generator-side converters regulate power through rotating reserve capacity and wind curtailment frequency regulation, determining generation power based on wind speed and grid frequency information to control the electromagnetic torque of the permanent magnet wind turbine generator. This matches randomly changing wind power to the ever-fluctuating grid frequency, achieving demand-side response.
[0034] The generator-side converter regulates frequency by controlling active power. When the grid frequency is higher than the rated frequency, the active power is reduced by curtailing wind power from the permanent magnet wind turbine generators; when the grid frequency is lower than the rated frequency, the spinning reserve capacity increases active power, thus achieving frequency regulation. At that time, Δf > 0 (frequency increases). Power generation is reduced by curtailing wind power. At that time, Δf < 0 (frequency decreases). Permanent magnet wind turbine generators increase power output by rotating spare capacity.
[0035] The formula for calculating the active power of the above-mentioned direct-drive fan rotational inertia standby primary frequency control system is as follows:
[0036]
[0037] The formula for calculating the adjustment of active power is:
[0038] ΔP=-Δf·K d ,
[0039] The formula for calculating spinning reserve capacity is as follows:
[0040]
[0041] In the above formula The active power of the primary frequency control system is used to reserve the rotational inertia of the direct-drive wind turbine. ΔP is the adjustment amount of the active power. reserve For spinning reserve capacity, P ref K represents the active power in maximum power point tracking mode. d ω is the virtual droop coefficient, J is the rotational inertia of the direct-drive wind turbine, and ω is the angular velocity, reflecting the sensitivity of the frequency deviation at the grid connection point to the adjustment of the output power of the wind turbine drive mechanism.
[0042] In the primary frequency control system for the backup rotational inertia of the direct-drive wind turbine, a phase-locked loop (PLL) can be added. The PLL detects the grid frequency and phase, and adjusts the power of the machine-side converter in the back-to-back dual PWM converter through shared control signals.
[0043] The control parameters of both the machine-side and grid-side converters are calibrated by amplitude normalization. When the active power of the primary frequency control system for the direct-drive wind turbine's rotating inertia reserve is 1MW, the control parameters of the machine-side and grid-side converters can be determined as follows: Figure 2 As shown, the parameters are highly consistent.
[0044] When the grid frequency fluctuates between 49.8Hz and 50.2Hz, the aforementioned direct-drive wind turbine rotational inertia backup primary frequency control system is used to perform the primary frequency regulation response of the wind turbine, such as... Figure 3As shown, the frequency change is divided into four stages. Stage 1 is the steady-state state at 49.8 Hz, where the permanent magnet wind turbine generator is in spinning reserve capacity mode. Stage 2 is from 49.8 Hz to 50.2 Hz, where the permanent magnet wind turbine generator switches from spinning reserve capacity mode to wind curtailment frequency regulation mode. Stage 3 is the steady-state state at 50.2 Hz, where the permanent magnet wind turbine generator is in wind curtailment frequency regulation mode. Stage 4 is from 50.2 Hz to 49.8 Hz, where the permanent magnet wind turbine generator switches from wind curtailment frequency regulation mode to spinning reserve capacity mode. In stages 2 and 4 of the diagram, it can be seen that the voltage fluctuates slightly during the frequency change stages but quickly returns to normal. When the frequency changes, the permanent magnet wind turbine generator adjusts its active power... Responding to frequency regulation requirements directly causes a proportional change in current I. Theoretically, as the frequency increases, the current decreases, and vice versa. In stage 2, a noticeable decrease in current is observed, while in stage 4, the current increases. Theoretically, when the frequency increases, the permanent magnet wind turbine achieves frequency regulation through wind curtailment (reducing active power). When the frequency decreases, the permanent magnet wind turbine needs to increase active power output, requiring spinning reserve capacity. In stage 2, active power decreases, while in stage 4, active power increases.
[0045] All of the above-mentioned undisclosed matters can be implemented using existing technologies, so they will not be elaborated here.
[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0047] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.
[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A primary frequency regulation control system for the backup rotational inertia of a direct-drive fan, characterized in that, The direct-drive wind turbine rotating inertia reserve primary frequency control system includes a back-to-back dual PWM converter connected to the permanent magnet wind turbine generator and the power grid. The direct-drive wind turbine rotating inertia reserve primary frequency control system addresses the frequency drop at the grid connection point by increasing the rotating reserve capacity, and addresses the frequency rise at the grid connection point by adjusting the curtailment frequency.
2. The primary frequency regulation control system for backup rotational inertia of a direct-drive fan according to claim 1, characterized in that, The permanent magnet wind turbine generator set includes a wind turbine converter and a permanent magnet synchronous generator.
3. The primary frequency regulation control system for backup rotational inertia of a direct-drive fan according to claim 2, characterized in that, An encoder is installed on the fan rotor shaft in the fan drive mechanism. The encoder is used to detect the position and wind speed of the fan rotor so as to adjust the power of the machine-side converter in the back-to-back dual PWM converter.
4. The primary frequency control system for the backup rotational inertia of a direct-drive fan according to any one of claims 1 to 3, characterized in that, The back-to-back dual PWM converter includes a machine-side converter and a grid-side converter, wherein... The generator-side converter regulates power by rotating reserve capacity and wind curtailment frequency regulation, and determines the power generation capacity by wind speed and grid frequency information, and controls the electromagnetic torque. The grid-side converter operates by stabilizing the DC bus voltage, converting the frequency fluctuations on the AC side into the voltage fluctuations on the DC side, which serves as a channel for power transfer.
5. The primary frequency regulation control system for backup rotational inertia of a direct-drive fan according to claim 4, characterized in that, The generator-side converter regulates frequency by controlling active power. The specific process is as follows: when the grid frequency is greater than the rated frequency, the permanent magnet wind turbine generator reduces active power by curtailing wind power; when the grid frequency is less than the rated frequency, the spinning reserve capacity releases active power.
6. The primary frequency regulation control system for backup rotational inertia of a direct-drive fan according to claim 5, characterized in that, The formula for calculating the active power of the primary frequency control system for the standby moment of inertia of a direct-drive fan is as follows: The formula for calculating the adjustment of active power is ΔP = -Δf·K d , The formula for calculating spinning reserve capacity is as follows: In the above formula The active power of the primary frequency control system is used to reserve the rotational inertia of the direct-drive wind turbine. ΔP is the adjustment amount of the active power. reserve For spinning reserve capacity, P ref K represents the active power in maximum power point tracking mode. d ω is the virtual droop coefficient, J is the rotational inertia of the direct-drive fan, and ω is the angular velocity.
7. The primary frequency regulation control system for backup rotational inertia of a direct-drive fan according to claim 4, characterized in that, The calibration of the control parameters of the machine-side converter and the grid-side converter is achieved by normalizing the amplitude. The control parameters of the machine-side converter include machine-side current and machine-side power, and the control parameters of the grid-side converter include grid-side voltage and current.
8. The primary frequency regulation control system for backup rotational inertia of a direct-drive fan according to claim 1, characterized in that, The primary frequency control system for the rotational inertia backup of the direct-drive wind turbine also includes a phase-locked loop (PLL). The PLL detects the grid frequency and phase, and adjusts the power of the machine-side converter in the back-to-back dual PWM converter by sharing control signals.