Doubly-fed wind turbine control method, system and storage medium

Abstract

The present invention belongs to the field of new energy power generation equipment, and in particular relates to a control method, system and storage medium for a doubly-fed wind turbine generator set, which obtains a real-time angular frequency deviation signal of a power grid. When the system frequency deviation is greater than a specified value, the bandwidth of a phase-locked loop is adjusted; and a final rotor d-axis current reference instruction is calculated; a reactive power reference instruction is calculated based on the q-axis current reference instruction, a reactive control link is introduced, and the rotor q-axis current reference instruction is calculated by a reactive controller; based on the new current reference signal, the doubly-fed wind turbine generator set generates a new control signal by an upper-level control loop, so that the doubly-fed wind turbine generator outputs corresponding active power and reactive power, thereby achieving rapid and active support for the power grid frequency; compared with the frequency control method implemented in the existing phase-locked loop, the method has the advantages of not requiring the introduction of a differential operator, fast frequency response, simple control structure, and no need to adjust the phase-locked loop bandwidth to a lower value, while maintaining the accuracy of the phase-locked loop phase angle tracking.

Description

Technical Field

[0001] The present invention belongs to the field of new energy power generation equipment, and in particular relates to a control method, system and storage medium for a doubly-fed wind turbine generator set. Background Art

[0002] my country is gradually transitioning from a traditional power system dominated by thermal power to a new power system dominated by renewable energy. However, with the continued increase in renewable energy penetration, the stability of my country's power system has significantly decreased, the active support capabilities of power generation equipment have been significantly weakened, and system voltage and frequency issues have become prominent. To address the increasingly deteriorating system dynamics, the grid guidelines have set clear requirements for renewable energy power generation equipment in terms of active grid support. Specifically, renewable energy power generation equipment must be able to provide voltage and frequency support capabilities similar to those of synchronous generators during grid disturbances.

[0003] Inertia control, as the initial stage of frequency control, determines the maximum frequency rate of change and maximum frequency deviation of the system in the initial phase. Existing inertia control strategies for doubly-fed wind turbines primarily add frequency rate-related variables to the active power reference command. However, this approach often requires the introduction of frequency derivatives, which can easily introduce high-frequency noise and affect system stability. Furthermore, this approach generally results in a slow inertia response. Phase-locked loops (PLLs) are generally faster than active power control loops. Therefore, theoretically, using PLLs to implement inertia control offers a faster response speed. Some researchers have achieved virtual inertia control for doubly-fed wind turbines by reducing the PLL bandwidth. However, this approach typically requires adjusting the PLL bandwidth to below 1 Hz, resulting in a relatively slow response speed and a small increase in active power during the inertia response period. Research has attempted to achieve inertia response by introducing frequency derivative-related or step terms into the PLL output phase angle. However, this control approach, due to the introduction of an additional control loop, also presents stability issues.

[0004] How to achieve the inertia response of the doubly fed wind turbine generator system, take into account the rapidity of the inertia response, avoid the stability problems caused by the differential operator, and minimize the modification of the existing control loop has become a key technical problem that needs to be solved urgently. Summary of the Invention

[0005] The present invention provides a control method, system and storage medium for a doubly-fed wind turbine generator set, which mainly solve the problems of slow power response speed and poor stability in the current grid frequency active support control process.

[0006] To achieve the above object, the present invention provides a fast frequency response control method for a doubly-fed wind turbine generator system, comprising the following steps:

[0007] The real-time angular frequency deviation signal of the power grid is obtained through the phase-locked loop. When the frequency deviation is detected to be greater than the specified value, the bandwidth of the phase-locked loop is adjusted;

[0008] The active power control loop is removed, and the rotor D-axis current reference command is calculated based on the active power reference command given by the power tracking curve. At the same time, a frequency deviation droop additional current reference command is introduced into the rotor D-axis current reference command to obtain the final rotor D-axis current reference command.

[0009] The reactive power reference command is calculated based on the q-axis current reference command, a reactive power control link is introduced, and the rotor q-axis current reference command is calculated through the reactive controller;

[0010] Based on the new current reference signal, the upper control loop of the doubly-fed wind turbine generates a new control signal, so that the doubly-fed wind turbine outputs corresponding active power and reactive power, achieving rapid and active support for the grid frequency.

[0011] Furthermore, when it is detected that the frequency deviation is greater than 0.2 Hz, the bandwidth of the phase-locked loop is adjusted to 1 Hz to 3 Hz.

[0012] Furthermore, the real-time angular frequency deviation signal of the power grid is oh err， The calculation expressions include:

[0013] ;

[0014] Where: oh is the real-time angular frequency of the system; oh 0 is the rated angular frequency of the system;

[0015] System angular frequency deviation signal oh err and frequency deviation signal f err The relationships between them include:

[0016] ;

[0017] The bandwidth of the phase-locked loop is adjusted by adjusting the parameters of the phase-locked loop PI controller. The specific calculation expressions include:

[0018] Phase-locked loop ratio parameters k ppll The expression is:

[0019] ;

[0020] Phase-locked loop integral parameters k ipll The expression is:

[0021] ;

[0022] Where: oh -3dB is the angular frequency corresponding to the phase-locked loop bandwidth; g pll is the phase-locked loop damping ratio.

[0023] Furthermore, the calculation expression of the final rotor d-axis current reference instruction includes:

[0024] ;

[0025] Where: L s is the stator inductance, L m is the magnetizing inductance, V s is the stator voltage, D P is the grid frequency deviation damping coefficient, P ref is the active power reference instruction, f err It is the system frequency deviation detected by the phase-locked loop.

[0026] Furthermore, the calculation expression between the reactive power reference instruction and the rotor q-axis current reference instruction includes:

[0027] ;

[0028] Where: Q ref is the reactive power reference instruction, I rqref For the rotor q Axis current reference command; L s is the stator inductance, L m is the magnetizing inductance, V s is the stator voltage; oh 0 is the rated angular frequency of the system.

[0029] The present invention further provides a control system for a phase-locked loop electronic power device, using the above-mentioned fast frequency response control method for a doubly-fed wind turbine generator system, comprising:

[0030] Sampling and processing unit: used to collect stator and rotor voltage and current signals, motor rotor angle signals and rotor angular velocity signals;

[0031] Phase-locked loop: calculates the system phase reference signal based on the stator voltage measurement;

[0032] Coordinate transformation unit: used to convert the three-phase voltage and current AC signals in the three-phase stationary coordinate system into two-phase voltage and current DC signals in the two-phase rotating coordinate system;

[0033] Output power control loop: The d-axis and q-axis current reference commands for the input rotor current control loop are calculated through closed-loop regulation using active power reference command, reactive power reference command, and feedback measurement.

[0034] Rotor current control loop: The modulated voltage signal is calculated by closed-loop regulation through rotor current command and rotor measurement;

[0035] Space vector modulator: used to generate PWM control signals for controlling the rotor-side converter switches through space vector modulation;

[0036] Rotor-side converter: The switching signal input terminal is connected to the output terminal of the space vector modulator.

[0037] Furthermore, the sampling processing unit includes:

[0038] Sampling unit: used to collect the stator voltage signal of the doubly fed motor V sabc , rotor current signal I rabc；

[0039] Encoder unit: used to obtain the rotor angle of the doubly fed motor i r and rotor angular velocity oh r ;

[0040] The phase-locked loop comprises:

[0041] Park coordinate transformation unit: used to transform the stator voltage signal in the three-phase stationary coordinate system V sabc Transformed into the stator d-axis voltage in the two-phase rotating coordinate system V sd , q-axis voltage V sq ;

[0042] Controller unit: used to calculate the system angular frequency deviation signal according to the q-axis voltage;

[0043] Adder unit: used to superimpose the system rated angular frequency signal to obtain the system real-time angular frequency signal;

[0044] Integrator unit: used to obtain the phase angle of the grid-connected point voltage by integrating the system's real-time angular frequency signal i pll ;

[0045] The coordinate transformation unit includes:

[0046] Park coordinate transformation unit: used to transform the stator voltage signal in the three-phase stationary coordinate system V sabc and rotor current signal I rabc Transformed into the stator d-axis voltage in the two-phase rotating coordinate system V sd , q-axis voltage V sq , rotor d-axis current I rd , q-axis current I rq ;

[0047] The output power control loop includes:

[0048] Subtractor unit: used to obtain the error signal by subtracting the reference signal from the feedback signal;

[0049] Controller unit: The active power controller is used to perform closed-loop processing on the active power to obtain the rotor d-axis current reference signal, and the reactive power controller is used to perform closed-loop processing on the reactive power to obtain the rotor q-axis current reference signal;

[0050] Output limiter unit: used to ensure that the output current reference instruction does not exceed the current limit that the equipment can withstand;

[0051] The rotor current control loop comprises:

[0052] Feedforward unit: through the rotor d-axis current I rd , q-axis current I rq To calculate the feedforward compensation signal V rdc 、 V rqc ;

[0053] Controller unit: According to the rotor d-axis current instruction I rdref , q-axis current command I rqref and the actual rotor d-axis current I rd , q-axis current I rq , calculate the d-axis error signal I errd , q-axis error signal I errq The controller unit includes a first controller and a second controller, wherein the first controller is used to convert the d-axis error signal I errdPerform closed-loop regulation to obtain the converter d-axis voltage modulation signal V rd The second controller is used to convert the q-axis error signal I errq Perform closed-loop regulation to obtain the converter q-axis voltage modulation signal V rq ;

[0054] The space vector modulator is used to modulate the signal V rd 、 V rq Perform SVPWM modulation to obtain the PWM control signal of the rotor side converter switch tube V rabc This signal is used to control the on and off of the switch tube in the rotor-side converter, thereby regulating the output voltage signal of the rotor-side converter.

[0055] The present invention also provides a control method for a doubly-fed wind turbine generator system, comprising the following steps:

[0056] Collect the real-time angular frequency deviation signal of the power grid. When the frequency deviation is detected to be greater than 0.2 Hz, the bandwidth of the phase-locked loop is immediately adjusted to 1 Hz to 3 Hz.

[0057] A new rotor d-axis current reference instruction and a rotor q-axis current reference instruction are obtained by using the above-mentioned fast frequency response control method of the doubly-fed wind turbine generator set;

[0058] Based on the new rotor d-axis current reference instruction and the rotor q-axis current reference instruction, vector control is adopted to control the doubly fed wind turbine to quickly output power to the grid, thereby achieving rapid and active support for the grid frequency.

[0059] The present invention also provides a storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned fast frequency response control of the doubly-fed wind turbine generator set or the control method of the doubly-fed wind turbine generator set.

[0060] The technical solution provided by the present invention has at least the following technical effects:

[0061] The invention discloses a fast frequency response control method for a doubly-fed wind turbine generator system, which obtains a new rotor d-axis current reference instruction, a rotor q-axis current reference instruction, and a reactive power reference signal. Q ref; Based on the new current reference command signal, the doubly fed wind turbine generator set generates a new control signal by the upper control loop, so that the doubly fed wind turbine generator set has corresponding active power and reactive power, thereby realizing active support for the grid frequency. Since the dynamic response of the active and reactive control loops coupling to the frequency support is more prominent during the frequency support period, the method of the present invention can achieve the control goal of rapid active support for the grid frequency, with fast response speed, simplicity and ease. Compared with the frequency control method implemented in the existing phase-locked loop, it has the advantages of no need to introduce a differential operator, fast frequency response, simple control structure, and no need to adjust the phase-locked loop bandwidth to a lower value, and maintains the accuracy of the phase-locked loop phase angle tracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0063] Figure 1 A flowchart of a fast frequency response control method for a doubly-fed wind turbine generator system provided in the first embodiment of the present invention;

[0064] Figure 2 The main circuit topology structure of the doubly-fed wind turbine provided in the first embodiment of the present invention;

[0065] Figure 3 A schematic diagram of a phase-locked loop structure and a schematic diagram of a fast frequency response control method modified in a phase-locked loop in the first embodiment of the present invention;

[0066] Figure 4 Schematic diagram of upper-layer control and active power and reactive power control of a doubly-fed wind turbine generator system in Embodiment 1 of the present invention;

[0067] Figure 5 This is a graph showing experimental results corresponding to steps 110 and 120 of the method of the first embodiment of the present invention after a sudden drop in grid frequency;

[0068] Among them, (a) is a graph showing the experimental results of the wind turbine output power change and the system frequency change rate when the method of the present invention is used without active power control; (b) is a graph showing the experimental results of the wind turbine output power change and the system frequency change rate when the method of the present invention is used with active power control;

[0069] Figure 6 This is a graph of experimental results corresponding to step 110 and step 130 of the method of the embodiment of the present invention after a sudden drop in grid frequency provided in the first embodiment of the present invention;

[0070] Among them, (a) is a graph showing the experimental results of the wind turbine output power change and the system frequency change rate when the method of the present invention adopts reactive power control; (b) is a graph showing the experimental results of the wind turbine output power change and the system frequency change rate when the method of the present invention adopts active power and reactive power control;

[0071] Figure 7 This is a graph showing the experimental results corresponding to all steps of the first embodiment of the present invention after a sudden drop in grid frequency;

[0072] Where (a) is the phase-locked loop bandwidth set to 1 Hz, the droop coefficient D p =0.01; (b) shows the experimental results of the phase-locked loop with a bandwidth of 1 Hz and a droop coefficient of D p =0.005 corresponding experimental results; (c) is the phase-locked loop bandwidth is set to 2 Hz, the droop coefficient D p =0.01 corresponding experimental results.

[0073] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0074] 1. Sampling and processing unit; 2. Phase-locked loop; 3. Coordinate transformation unit; 4. Output power control loop; 5. Rotor current control loop; 6. Space vector modulator; 7. Rotor-side converter. DETAILED DESCRIPTION

[0075] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0076] Example 1: This embodiment discloses a fast frequency response control method for a doubly-fed wind turbine generator system, such as Figure 1 As shown, the following steps are included:

[0077] Step 110: Acquire a real-time angular frequency deviation signal of the power grid through a phase-locked loop.

[0078] The method for judging the deviation of the grid frequency from the rated value is as follows: Figure 2 As shown in the figure, the main circuit topology of the doubly fed wind turbine is: Figure 2 In the equation, DFIG stands for doubly fed wind turbine. U rabc Inverter drive signal; RSC stands for rotor side converter; U dc Indicates the DC bus voltage;I sabc Indicates the three-phase current output on the stator side. oh r represents the rotor angular velocity, i r Indicates the rotor rotation angle. Figure 3 As shown in the figure, the phase-locked loop used in this paper works as follows: collecting the port voltage signal of the double-fed wind turbine connected to the grid V sabc ; The port voltage signal in the three-phase stationary coordinate system is transformed by coordinate transformation V sabc Transformed into the port voltage in the two-phase stationary coordinate system V αβ ; The port voltage signal in the two-phase stationary coordinate system is transformed by coordinate transformation V αβ Transformed into the port voltage in the two-phase rotating coordinate system V sd and V sq , where the coordinate transformation angle signal i pll Provided by the phase-locked loop output phase signal; q Shaft voltage signal V sq Input PI0 controller to get the real-time angular frequency of the system oh and rated angular frequency oh 0 angular frequency deviation signal oh err = oh - oh 0, system angular frequency deviation signal oh err and frequency deviation signal f err The relationship between them is: oh err =2π f err , frequency deviation signal f err = f - f 0, where: f is the system real-time frequency, f 0 is the rated frequency of the system, so the angular frequency deviation signal oh err Can be used to indirectly determine the degree to which the system frequency deviates from the rated value, angular frequency deviation signal oh err and rated angular frequency signal oh 0 is added to get the real-time angular frequency signal oh ; Real-time angular frequency signal ohThe phase angle signal reference of the entire system is obtained through the integration link i pll .

[0079] When the grid frequency deviation is detected to be greater than 0.2 Hz, the system switches to frequency support mode. By switching the PLL's PI controller from mode 0 to mode 1, the PLL bandwidth is adjusted to 1 Hz to 3 Hz. In this embodiment, the bandwidth is adjusted to about 2 Hz. This allows for flexible PLL bandwidth adjustment to quickly respond to frequency drops. The specific calculation expression is:

[0080] Phase-locked loop ratio parameters k ppll The expression is:

[0081] ;

[0082] Phase-locked loop integral parameters k ipll The expression is:

[0083] ;

[0084] in: oh -3dB is the angular frequency corresponding to the phase-locked loop bandwidth, g pll is the phase-locked loop damping ratio, usually 0.707.

[0085] Step 120: The active power control loop is removed, and the rotor D-axis current reference command is calculated based on the active power reference command given by the power tracking curve. Meanwhile, a frequency deviation droop additional current reference command is introduced into the rotor D-axis current reference command to obtain a final rotor D-axis current reference command.

[0086] Step 130: Calculate the reactive power reference command according to the q-axis current reference command, introduce a reactive power control link, and calculate the rotor q-axis current reference command through the reactive power controller;

[0087] like Figure 4 As shown, steps 120 and 130 are specifically as follows:

[0088] First, collect the voltage signal of the double-fed wind turbine port V sabc , rotor current signal I rabc And the rotor position angle signal i r :Use the above obtained i pll Perform coordinate transformation to convert the port voltage signal in the three-phase stationary coordinate system into V sabcTransform the voltage amplitude signal to the two-phase rotating coordinate system; use the phase information obtained above i pll And the rotor position angle signal i r Perform coordinate transformation to transform the rotor current signal in the three-phase stationary coordinate system I rabc Current signal transformed into two-phase rotating coordinate system I rd and I rq .

[0089] When the grid frequency is detected to be 0.2 Hz off the rated value, the active power and reactive power control loops are switched from mode 0 to mode 1, i.e., frequency support mode. At this time, the rotor current active reference value is no longer obtained by the active power closed-loop control, but is calculated by the active power reference command calculated according to the power tracking curve to calculate the rotor D-axis current reference command. I rd * Introducing frequency deviation droop additional current reference instruction I P , the specific expression is:

[0090] First, collect the voltage signal of the double-fed wind turbine port V sabc , rotor current signal I rabc And the rotor position angle signal i r :Use the above obtained i pll Perform coordinate transformation to convert the port voltage signal in the three-phase stationary coordinate system into V sabc Transform the voltage amplitude signal to the two-phase rotating coordinate system; use the phase information obtained above i pll And the rotor position angle signal i r Perform coordinate transformation to transform the rotor current signal in the three-phase stationary coordinate system I rabc Current signal transformed into two-phase rotating coordinate system I rd and I rq .

[0091] When the grid frequency is detected to be 0.2 Hz off the rated value, the active power and reactive power control loops are switched from mode 0 to mode 1, i.e., frequency support mode. At this time, the rotor current active reference value is no longer obtained by the active power closed-loop control, but is calculated by the active power reference command calculated according to the power tracking curve to calculate the rotor D-axis current reference command. I rd * Introducing frequency deviation droop additional current reference instruction I P , the specific expression is:

[0092] ;

[0093] Where: L s is the stator inductance, L m is the magnetizing inductance, V s is the stator voltage, D P is the grid angular frequency deviation damping coefficient, P ref is the active power reference instruction, f err It is the system frequency deviation detected by the phase-locked loop.

[0094] The deviation signal of the two I rdref = I rd * - I P Make the difference to get the rotor d Shaft current reference signal I rdref Secondly, through q The shaft current reference command calculates the reactive power reference command, introduces the reactive control link, and obtains the reactive power reference value. Q ref and Q e Make a difference and take the deviation signal of the two Q err = Q ref - Q e Input reactive power controller PI Q And limit the output result to get the rotor q Shaft current reference signal I rqref .

[0095] Reactive power reference command and rotorq The calculation expressions between axis current reference instructions include:

[0096] ;

[0097] Where: Q ref is the reactive power reference instruction, I rqref For the rotor q Axis current reference command; L s is the stator inductance, L m is the magnetizing inductance, V s is the stator voltage, oh 0 is the system rated angular frequency.

[0098] Finally, the rotor current is obtained d、q After axis reference current instruction I rdref 、 I rqref Afterwards, according to the rotor d Shaft current command I rdref , rotor q Shaft current command I rqref Respectively and actual rotor d Shaft current I rd 、 q Shaft current I rq Compare to obtain d Axis error signal I errd 、 q Axis error signal I errq ,in, I errd = I rdref - I rd , I errq = I rqref - I rq ;right d Axis error signal I errd and q Axis error signal I errq PI controllers are used for closed-loop control to obtain the converter d Shaft voltage modulation signalV rd , converter q Shaft voltage modulation signal V rq ;Modulate the rotor signal V rd 、 V rq According to the phase information i pll and rotor position angle i r Perform inverse coordinate transformation to obtain the rotor modulation voltage in the two-phase stationary coordinate system V rα * 、 V rβ * ; Modulate the signal V rα * 、 V rβ * Input to the SVPWM module for processing to obtain the drive signal of the rotor side converter power tube V rabc .

[0099] Step 140: Based on the new current reference signal, the upper control loop of the doubly-fed wind turbine generates a new control signal, so that the doubly-fed wind turbine outputs corresponding active power and reactive power, thereby achieving rapid and active support for the grid frequency.

[0100] To better illustrate the effectiveness of the method of this embodiment, a simulation study is conducted using a wind farm consisting of 80 typical 1.5MW doubly-fed wind turbines as an example. Before the fault occurred, the system frequency was at the rated frequency, and the doubly-fed turbines were outputting a stable power of 0.7 pu. Six seconds later, the system experienced a sudden load increase. The experimental results of the output power and system frequency obtained using steps 110 and 120 of the control method proposed in this embodiment are shown in the figure below. Figure 5 As shown, Figure 5 (a) shows the change of the wind turbine output active power and system frequency change rate when the active power control and reactive power control are not used in this embodiment. Figure 5 (b) adopts the control scheme with active power control and no reactive power control. The active power increase of the wind turbine is significantly improved and the system frequency change rate is significantly reduced.

[0101] Figure 6 (a) shows the change of the wind turbine output active power and system frequency under the embodiment without active control and reactive control, compared with Figure 6(b) in the figure adopts the control scheme under active control and no reactive control, the active power increase of the wind turbine is significantly improved, and the system frequency change rate is significantly reduced.

[0102] Figure 7 In order to use the complete control scheme of this embodiment, the output active power of the wind turbine of the power grid and the system frequency change show an obvious primary frequency modulation response in addition to the inertial response.

[0103] Example 2: This example discloses a control system for a phase-locked loop power electronic device based on the method of Example 1, including: a sampling processing unit 1, a phase-locked loop 2, a coordinate transformation unit 3, an output power control loop 4, a rotor current control loop 5, a space vector modulator 6, and a rotor-side converter 7 in the main circuit of a doubly fed wind turbine generator set.

[0104] Among them, the input end of the sampling and processing unit 1 is connected to the stator and rotor sides of the doubly fed motor, and is used to collect the stator and rotor voltage and current signals, the motor rotor angle signal and the rotor angular velocity signal. The stator voltage measurement at its output end is connected to the input end of the phase-locked loop 2 and the coordinate transformation unit 3; the rotor current measurement at its output end is connected to the input end of the coordinate transformation unit 3.

[0105] The phase-locked loop 2 calculates the phase reference signal of the system according to the stator voltage measurement, and its output end is connected to the input end of the coordinate transformation unit 3 and the space vector modulator 6.

[0106] The coordinate transformation unit 3 converts the three-phase voltage and current AC signals in the three-phase stationary coordinate system into two-phase voltage and current DC signals in the two-phase rotating coordinate system. The power measurement at its output end is connected to the feedback end of the output power control loop 4, and the rotor current signal at its output end is connected to the feedback end of the rotor current control loop 5.

[0107] The output power control loop 4 performs closed-loop regulation by the reference command and feedback measurement to calculate the input rotor current control loop 5. d 、 q Axis current reference command.

[0108] The rotor current control loop 5 performs closed-loop regulation through the rotor current command and rotor measurement to calculate a modulation voltage signal, and its output end is connected to the modulation input end of the space vector modulator 6.

[0109] The space vector modulator 6 is used to generate a PWM control signal for controlling the switch tube of the rotor-side converter through space vector modulation, and its output end is connected to the switching signal input end of the rotor-side converter 7.

[0110] In the embodiment of the present invention, the sampling processing unit 1 includes: a sampling unit for collecting the stator voltage signal of the doubly fed motor Vsabc , rotor current signal I rabc ; Encoder unit, used to obtain the rotor angle of the doubly fed motor i r and rotor angular velocity oh r .

[0111] Phase-locked loop 2 includes: Park coordinate transformation unit, which is used to transform the stator voltage signal in the three-phase stationary coordinate system V sabc Transformed into the stator in a two-phase rotating coordinate system d Shaft voltage V sd 、 q Shaft voltage V sq ; Controller unit for q The shaft voltage is used to calculate the system angular frequency deviation signal; the adder unit is used to superimpose the system rated angular frequency signal to obtain the system real-time angular frequency signal; the integrator unit is used to obtain the phase angle of the grid connection point voltage by integrating the system real-time angular frequency signal i pll .

[0112] The coordinate transformation unit 3 includes: a Park coordinate transformation unit for transforming the stator voltage signal in the three-phase stationary coordinate system into V sabc and rotor current signal I rabc Transformed into the stator in a two-phase rotating coordinate system d Shaft voltage V sd 、 q Shaft voltage V sq , rotor d Shaft current I rd 、 q Shaft current I rq .

[0113] The power control loop 4 includes: a subtractor unit for performing a difference between a reference signal and a feedback signal to obtain an error signal; a controller unit, an active power controller for performing a closed-loop processing on the active power to obtain the rotor d The shaft and current reference signals and the reactive power controller are used to perform closed-loop processing on the reactive power to obtain the rotor q Axis current reference signal; output limiter unit, used to ensure that the output current reference instruction does not exceed the current limit that the equipment can withstand.

[0114] The rotor current control loop 5 includes: a feedforward unit, through the rotor dShaft current I rd 、 q Shaft current I rq To calculate the feedforward compensation signal V rdc 、 V rqc ; Controller unit, according to the rotor d Shaft current command I rdref 、 q Shaft current command I rqref and the actual rotor d Shaft current I rd 、 q Shaft current I rq , calculated d Axis error signal I errd 、 q Axis error I errq , wherein the first controller is used to d Axis error signal I errd Perform closed-loop regulation to obtain a converter d Shaft voltage modulation signal V rd The second controller is used to q Axis error signal I errq Perform closed-loop regulation to obtain a converter q Shaft voltage modulation signal V rq .

[0115] The space vector modulator 6 is used to modulate the signal V rd 、 V rq Perform SVPWM modulation to obtain the PWM control signal of the rotor side converter switch tube V rabc This signal is used to control the on and off of the switch tube in the rotor-side converter, thereby regulating the output voltage signal of the rotor-side converter.

[0116] This embodiment improves the power control loop of the doubly fed wind turbine generator system. The grid angular frequency deviation signal is obtained in real time through the phase-locked loop. When the frequency deviation is detected to be greater than 0.2 Hz, the bandwidth of the phase-locked loop is immediately adjusted to about 2 Hz. The active power control loop is cut off and the rotor is calculated according to the active power reference instruction. d The shaft current reference value, at the same time in the rotor dThe frequency deviation is introduced into the shaft current to reduce the additional current reference instruction and obtain the final rotor d Shaft current reference command; according to the rotor q The shaft current reference command calculates the reactive power reference command, and at the same time introduces the reactive power control link to calculate the rotor through the reactive power controller. q Shaft current reference instruction; the upper-level control of the doubly fed wind turbine generator set obtains a new control signal based on the new current reference signal, so that the doubly fed wind turbine generator set can actively provide fast frequency support.

[0117] Specifically, it includes: firstly obtaining the grid angular frequency deviation signal through the phase-locked loop; secondly switching the power control and calculating the rotor active power reference instruction given by the power tracking curve; d Axis current reference instruction, while introducing the frequency deviation droop additional current reference instruction in the rotor d-axis current reference instruction, the output is the rotor d Axis current reference command I rdref .according to q The shaft current reference command calculates the reactive power reference command and introduces the reactive power control link. The output is the rotor reference command described in step 130. q Axis current reference command I rqref .

[0118] The upper-level control of the doubly-fed wind turbine generator system generates a new control signal by performing coordinate transformation based on the new current reference signal, so that the doubly-fed wind turbine generator system generates active power that meets the needs of the power grid. Therefore, the method of the present invention can achieve the control goal of rapid and active support for the power grid frequency, has a fast response speed, is simple and easy to implement, and can effectively provide rapid and active frequency support when frequency disturbances occur. It can not only quickly slow down the change of system frequency without investing in any hardware devices, but also maintain the accuracy of the phase-locked loop phase. It should be noted that the frequency response of conventional wind turbines requires the PLL bandwidth to be reduced to 1 Hz or even lower, while the present invention only needs to reduce the PLL bandwidth to about 2 Hz.

[0119] Active current damping link, specifically:

[0120] The real-time angular frequency deviation signal of the power grid is obtained based on the phase-locked loop. The angular frequency deviation signal is controlled by the power grid frequency deviation damping to obtain the damping signal. I P ;

[0121] Preferably, the rotor current reference signal during the frequency disturbance is the accumulation of the droop term and the original rotor current term, and the specific expression is: ;

[0122] in: Ls is the stator inductance, L m is the magnetizing inductance, V s is the stator voltage, D P is the grid frequency deviation damping coefficient, P ref is the active power reference instruction, f err It is the system frequency deviation detected by the phase-locked loop.

[0123] Compared with other frequency support methods, the frequency response speed is significantly improved, the structure is simple, and the portability is strong, which greatly enhances the active frequency support capability of new energy power generation equipment and maintains the accuracy of the steady-state tracking of the original phase-locked loop.

[0124] Embodiment 3: This embodiment discloses a control method for a doubly-fed wind turbine generator system, including:

[0125] Collect the real-time angular frequency deviation signal of the power grid. When the frequency deviation is detected to be greater than 0.2 Hz, immediately adjust the bandwidth of the phase-locked loop to 1 Hz to 3 Hz. In this embodiment, the bandwidth of the phase-locked loop is adjusted to about 2 Hz.

[0126] A new rotor d-axis current reference instruction and a rotor q-axis current reference instruction are obtained by using a fast frequency response control method for a doubly-fed wind turbine generator system as described in Example 1; the relevant technical solutions are the same as those in Example 1 and will not be described in detail here.

[0127] Based on the new rotor d-axis current reference instruction and the rotor q-axis current reference instruction, vector control is adopted to control the doubly fed wind turbine to quickly output power to the grid, thereby achieving rapid and active support for the grid frequency.

[0128] Adopting the grid frequency support control strategy as described above, adjusting the phase-locked loop bandwidth, calculating the rotor d-axis current reference instruction according to the active power reference instruction given by the power tracking curve, introducing the frequency deviation droop additional current reference instruction into the rotor d-axis current reference instruction, and introducing the reactive power control link, calculating the rotor q-axis current reference instruction through the reactive power controller, and obtaining a new active current reference signal I rdref and I rqref , and is used in the vector control of equipment power transmission. This bottom-level control method, on the one hand, enables the power generation equipment to actively and quickly support the grid frequency and maintain the accuracy of the phase-locked loop phase lock. On the other hand, it can achieve stable and reliable power generation tasks. It can be applied to direct-drive wind turbines, photovoltaic systems and other similar new energy power generation equipment and is simple and feasible.

[0129] Embodiment 4: This embodiment discloses a storage medium having instructions stored therein. When a computer reads the instructions, the computer executes the wind turbine fast frequency response control method described in Embodiment 1 or the control method for a doubly-fed wind turbine described in Embodiment 3.

[0130] The relevant technical solutions are the same as those in Example 1 and Example 3 and will not be described in detail here.

[0131] The above are only preferred embodiments of the present invention and are 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 in the scope of protection of the present invention.

Claims

1. A fast frequency response control method for a doubly-fed wind turbine generator system, characterized in that: The steps include: The real-time angular frequency deviation signal of the power grid is obtained through the phase-locked loop. When the frequency deviation is detected to be greater than the specified value, the bandwidth of the phase-locked loop is adjusted; The active power control loop is removed, and the rotor D-axis current reference command is calculated based on the active power reference command given by the power tracking curve. At the same time, a frequency deviation droop additional current reference command is introduced into the rotor D-axis current reference command to obtain the final rotor D-axis current reference command. The reactive power reference command is calculated based on the q-axis current reference command, a reactive power control link is introduced, and the rotor q-axis current reference command is calculated through the reactive power controller; Based on the new current reference signal, the upper control loop generates a new control signal for the doubly-fed wind turbine, which enables the doubly-fed wind turbine to output corresponding active power and reactive power, thus achieving rapid and active support for the grid frequency. The calculation expression for the final rotor D-axis current reference instruction includes: ； Where: L s is the stator inductance, L m is the magnetizing inductance, V s is the stator voltage, D P is the grid frequency deviation damping coefficient, P ref is the active power reference instruction, f err It is the system frequency deviation detected by the phase-locked loop.

2. The fast frequency response control method of a doubly-fed wind turbine generator system according to claim 1, characterized in that: When the frequency deviation is detected to be greater than 0.2 Hz, the bandwidth of the phase-locked loop is adjusted to 1 Hz to 3 Hz.

3. The fast frequency response control method of a doubly-fed wind turbine generator system according to claim 1, characterized in that: The real-time angular frequency deviation signal of the power grid is: ω err , whose calculation expressions include: ； Where: ω is the real-time angular frequency of the system; ω 0 is the rated angular frequency of the system; System angular frequency deviation signal ω err and frequency deviation signal f err The expressions between include: ； The bandwidth of the phase-locked loop is adjusted by adjusting the parameters of the phase-locked loop PI controller. The specific calculation expressions include: Phase-locked loop ratio parameters k ppll The expression is: ； Phase-locked loop integral parameters k ipll The expression is: ； Where: ω -3dB is the angular frequency corresponding to the phase-locked loop bandwidth; ζ pll is the phase-locked loop damping ratio.

4. The fast frequency response control method of a doubly-fed wind turbine generator system according to claim 1, characterized in that: The reactive power reference command and the rotor q The calculation expressions between axis current reference instructions include: ； Where: Q ref is the reactive power reference instruction, I rqref For the rotor q Axis current reference command; L s is the stator inductance, L m is the magnetizing inductance, V s is the stator voltage, ω 0 is the rated angular frequency of the system.

5. A control system for a phase-locked loop electronic power device, characterized in that: Using the fast frequency response control method for a doubly-fed wind turbine generator system according to any one of claims 1 to 4, the control system includes: Sampling and processing unit (1): used to collect stator and rotor voltage and current signals, motor rotor angle signals and rotor angular velocity signals; Phase-locked loop (2): calculates the phase reference signal of the system according to the stator voltage; Coordinate transformation unit (3): used to transform the three-phase voltage and current AC signals in the three-phase stationary coordinate system into two-phase voltage and current DC signals in the two-phase rotating coordinate system; Output power control loop (4): The rotor d and q axis current reference commands for the input rotor current control loop are calculated by closed-loop regulation using active power reference command, reactive power reference command and feedback measurement; Rotor current control loop (5): The modulated voltage signal is calculated by closed-loop regulation through the rotor current reference command and rotor measurement; Space vector modulator (6): used to generate a PWM control signal for controlling the rotor-side converter switch tube through space vector modulation; Rotor-side converter (7): The switch signal input terminal is connected to the output terminal of the space vector modulator.

6. The control system of the phase-locked loop electronic power device according to claim 5, characterized in that: The sampling processing unit (1) comprises: Sampling unit: used to collect the stator voltage signal of the doubly fed motor V sabc , rotor current signal I rabc； Encoder unit: used to obtain the rotor angle of the doubly fed motor θ r and rotor angular velocity ω r ; The phase-locked loop (2) comprises: Park coordinate transformation unit: used to transform the stator voltage signal in the three-phase stationary coordinate system V sabc Transformed into the stator d-axis voltage in the two-phase rotating coordinate system V sd , q-axis voltage V sq ; Controller unit: used to calculate the system angular frequency deviation signal according to the q-axis voltage; Adder unit: used to superimpose the system rated angular frequency signal and the system angular frequency deviation signal to obtain the system real-time angular frequency signal; Integrator unit: used to obtain the phase angle of the grid connection point voltage by integrating the system's real-time angular frequency signal θ pll ; The coordinate transformation unit (3) comprises: Park coordinate transformation unit: used to transform the stator voltage signal in the three-phase stationary coordinate system V sabc and rotor current signal I rabc Transformed into the stator d-axis voltage in the two-phase rotating coordinate system V sd , q-axis voltage V sq , rotor d-axis current I rd , q-axis current I rq ; The output power control loop (4) comprises: Subtractor unit: used to obtain the error signal by subtracting the reference signal from the feedback signal; Controller unit: The active power controller is used to perform closed-loop processing on the active power to obtain the rotor d-axis current reference instruction, and the reactive power controller is used to perform closed-loop processing on the reactive power to obtain the rotor q-axis current reference instruction; Output limiter unit: used to ensure that the output current reference instruction does not exceed the current limit that the equipment can withstand; The rotor current control loop (5) comprises: Controller unit: According to the rotor d-axis current reference instruction I rdref ,q-axis current reference command I rqref and the actual rotor d-axis current I rd , q-axis current I rq , calculate the d-axis error signal I errd , q-axis error signal I errq The controller unit includes a first controller and a second controller, wherein the first controller is used to convert the d-axis error signal I errd Perform closed-loop regulation to obtain the converter d-axis voltage modulation signal V rd The second controller is used to convert the q-axis error signal I errq Perform closed-loop regulation to obtain the converter q-axis voltage modulation signal V rq ; The space vector modulator (6) is used to modulate the signal V rd 、 V rq Perform SVPWM modulation to obtain the PWM control signal of the rotor side converter (7) switch tube V rabc This signal is used to control the on and off of the switch tube in the rotor-side converter (7), thereby regulating the output voltage signal of the rotor-side converter (7).

7. A control method for a doubly-fed wind turbine generator system, characterized in that: The steps include: Collect the real-time angular frequency deviation signal of the power grid. When the frequency deviation is detected to be greater than 0.2 Hz, the bandwidth of the phase-locked loop is immediately adjusted to 1 Hz to 3 Hz. A new rotor d-axis current reference instruction and a rotor q-axis current reference instruction are obtained by adopting the fast frequency response control method of the doubly-fed wind turbine generator set according to any one of claims 1 to 4; Based on the new rotor d-axis current reference instruction and the rotor q-axis current reference instruction, vector control is adopted to control the doubly fed wind turbine to quickly output power to the grid, thereby achieving rapid and active support for the grid frequency.

8. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 4 or claim 7 is implemented.

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