Doubly-fed wind turbine generator fast inertia response control method, generator control method and storage medium thereof

Abstract

The invention discloses a quick inertia response control method for a doubly-fed wind turbine generator, a generator control method and a storage medium thereof. The quick inertia response control method comprises the following steps: acquiring a power grid q-axis voltage signal under a two-phase rotating coordinate system in real time through a phase-locked loop; a power grid q-axis voltage signal is processed through a specific compensation link to obtain a phase-locked loop output phase compensation angle signal, the amplitude of the phase-locked loop output phase compensation angle signal is limited, the amplitude-limited compensation angle signal is subtracted from a phase angle signal output by an original phase-locked loop, and a new phase-locked angle signal is obtained; and on the basis of the phase-locked angle signal, an upper-layer control loop of the doubly-fed wind turbine generator generates a new voltage and current control signal, so that the rapid inertia response of the doubly-fed wind turbine generator to the power grid frequency is realized. According to the method provided by the invention, a common differential operator in an inertia control process is avoided, so that the stability of the system is improved, and meanwhile, the rapidity of inertia response is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the field of active frequency support of new energy power generation equipment, and more specifically, relates to a fast inertia response control method for a doubly-fed wind turbine set, a set control method and a storage medium thereof. Background Art

[0002] The large-scale access to new energy sources has led to significant changes in the basic form of the power system. The power system is gradually changing from a traditional power system dominated by thermal power to a new power system dominated by new energy sources. The new system form has given rise to new stability issues. Basic power quality indicators represented by frequency and voltage have fluctuated more violently than in the past. To this end, the grid guidelines have put forward new grid connection requirements for the access of new energy equipment. Taking frequency indicators as an example, the existing grid guidelines clearly point out that new energy power generation equipment needs to have active frequency support capabilities, and specifically put forward more detailed indicator requirements for inertia response and primary frequency regulation.

[0003] The improvement methods of the inertia control of existing wind turbines in the mechanical control loop mainly include modifying the power tracking curve and the pitch angle control link. In the converter control link, it can be mainly divided into adding an additional control loop on the basis of vector control or using virtual synchronous control to achieve active support for the grid frequency. The additional loop of vector control is mainly achieved by introducing a control quantity related to the frequency change rate in the power outer loop. The above methods all realize the active support of the grid frequency during system frequency disturbances. However, due to the fact that the control dynamics of the implementation loop are relatively slow, the inertia response is also relatively slow, and most of them need to introduce differential operators to characterize the system frequency change rate, which will greatly reduce the stability of the control system.

[0004] In recent years, some scholars have proposed implementing inertia control in a phase-locked loop and put forward a series of related control methods. Compared with the existing typical virtual inertia method, it has improved the rapidity of inertia response to a certain extent. However, there is still much room for optimization and improvement in the response speed of inertia control in the phase-locked loop.

[0005] To this end, the patent of this invention attempts to avoid the use of differential operators in inertia control and thus improve the stability of the control system on the one hand, and on the other hand is committed to improving the rapidity of implementing inertia control in the phase-locked loop. By improving stability and rapidity, fast and excellent inertia control of the doubly-fed wind turbine set during system frequency disturbances can be achieved. Summary of the invention

[0006] The present invention provides a fast inertia response control method for a double-fed wind turbine set to a grid frequency, which is used to solve the problems of slow response speed of the existing inertia control method and reduced stability due to introduction of a differential operator.

[0007] The technical solution of the present invention to solve the above technical problem is as follows: A method for controlling the fast inertia response of a doubly-fed wind turbine to the grid frequency, comprising:

[0008] Step S110: Obtain the grid q-axis voltage signal V in the two-phase rotating coordinate system in real time through a phase-locked loop sq , the grid q-axis voltage signal V sq After the compensation link, the phase compensation angle signal θ is obtained qs And limit the amplitude to obtain the compensation angle signal θ after limiting q ;

[0009] Step S120: The limited compensation angle signal θ q The phase angle output signal θ of the original phase-locked loop ori The new phase-locked angle output phase signal θ is obtained by subtracting pll ;

[0010] Step S130: Based on the new phase-locking angle signal θ pll , the upper control loop of the doubly-fed wind turbine generates a new control signal, which in turn enables the doubly-fed wind turbine to have a fast inertia response capability.

[0011] Based on the above technical solution, the present invention can also be improved as follows.

[0012] Preferably, the compensation step in step S110 is specifically as follows:

[0013] Based on the grid q-axis voltage signal V in the two-phase rotating coordinate system sq , the phase compensation angle signal θ is obtained through the relationship between active power, phase-locked loop, primary frequency change rate and secondary frequency change rate qs ;

[0014] Based on the phase compensation angle signal θ qs , the compensation angle signal is limited to obtain the compensation angle signal θ after limiting q , used to make a difference with the original phase angle output signal of the phase-locked loop.

[0015] Based on the above technical solution: the phase-locked loop output phase angle is related to the grid angular frequency change rate, and the phase-locked loop output phase angle is quickly increased or decreased, so that the doubly-fed wind turbine can provide a fast inertia response.

[0016] Preferably, the compensation angle signal in the phase-locked loop is:

[0017]

[0018] Where: k ipll K is the integral parameter of the phase-locked loop PI controller, F is the frequency second differential coefficient, J Fis the first differential coefficient of frequency, ζ is the damping ratio of the second-order filter, ω c is the oscillation frequency of the second-order filter, V sq is the q-axis voltage signal of the power grid in the two-phase rotating coordinate system.

[0019] Based on the above technical solution: the compensation link of this method calculates the compensation angle signal θ qs A second-order filtering link is introduced to more quickly filter out the high-order harmonics in the grid angular frequency, thereby eliminating the high-frequency noise entering the phase-locked loop and ensuring the stability of the system.

[0020] Preferably, the compensation angle signal θ qs After limiting, we get θ q , and the limited compensation angle signal θ q The original phase signal θ output by the phase-locked loop ori Subtract and get a new phase-locked loop signal θ pll .

[0021] Based on the above technical solution: set a limit value to limit the output result within a reasonable range to prevent the output result from exceeding the control capability of the doubly-fed wind turbine generator set.

[0022] The present invention also provides a control method for a doubly-fed wind turbine generator system, comprising:

[0023] The q-axis voltage signal V of the power grid in the two-phase rotating coordinate system is obtained in real time through the phase-locked loop sq , which is obtained by the output of the abc to dq transformation link of the double-fed wind turbine phase-locked loop;

[0024] The new phase-locked loop signal θ is obtained by using the fast inertia response control method of the double-fed wind turbine to the grid frequency. pll ;

[0025] Based on the new phase-locked loop signal θ pll , vector control is adopted to control the double-fed wind turbine to output active power to the grid and realize rapid inertia response to the grid frequency.

[0026] The present invention also provides a storage medium, in which instructions are stored. When a computer reads the instructions, the computer executes any one of the above-mentioned methods for controlling the fast inertia response of a doubly-fed wind turbine set to the grid frequency and / or any one of the above-mentioned methods for controlling the grid frequency of a doubly-fed wind turbine set.

[0027] The beneficial effects of the present invention are:

[0028] The present invention improves the phase-locked loop of a doubly-fed wind turbine generator set, introduces a grid q-axis voltage signal into an output phase angle signal of the phase-locked loop through a compensation link, and enables the doubly-fed wind turbine generator set to have a fast inertia response capability.

[0029] The control system for the grid frequency of the doubly-fed wind turbine of the present invention adopts the improved phase-locked loop as described above. After the grid q-axis voltage signal is obtained through the phase-locked loop, the output signal of the compensation link and the limiting link is subtracted from the phase angle signal of the original phase-locked loop to obtain a coordinate transformation angle signal that takes into account the grid frequency disturbance and is used in the vector control of the equipment power transmission. This method of bottom-level control, on the one hand, enables the power generation equipment to actively support the grid frequency, and on the other hand, can achieve stable and reliable power generation tasks. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flowchart of a method for controlling the fast inertia response of a doubly-fed wind turbine generator set to a grid frequency provided by an embodiment of the present invention;

[0031] Figure 2 A main circuit topology structure of a doubly-fed wind turbine generator system provided in an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of an improved doubly-fed wind turbine phase-locked loop provided in an embodiment of the present invention;

[0033] Figure 4 for Figure 3 The corresponding upper control diagram of the doubly-fed wind turbine generator set;

[0034] Figure 5 The phase compensation method provided in the embodiment of the present invention is an experimental effect diagram of the wind turbine active power and system frequency corresponding to the system frequency deviation through the first-order inertia and differential link;

[0035] Figure 6 The phase compensation method provided in the embodiment of the present invention is an experimental effect diagram of the system frequency change rate corresponding to the system frequency deviation passing through the first-order inertia and differential link;

[0036] Figure 7 This is the wind turbine active power and system frequency diagram corresponding to the method proposed in the present invention;

[0037] Figure 8 This is a diagram of the system frequency change rate corresponding to the method proposed in the patent of this invention.

[0038] Among them: 1. Sampling processing unit; 2. Improved phase-locked loop; 3. Coordinate transformation unit; 4. Active and reactive power control loop; 5. Rotor current control loop; 6. Space vector modulator; 7. Rotor side converter in the main circuit of the doubly-fed wind turbine. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] Embodiment 1

[0041] A fast inertia response control method for a doubly-fed wind turbine generator system to grid frequency, such as Figure 1 As shown, including:

[0042] Step 110: Obtain the grid q-axis voltage signal V in the two-phase rotating coordinate system in real time through a phase-locked loop sq , the grid q-axis voltage signal V sq After the compensation link, the phase compensation angle signal θ is obtained qs And limit the amplitude to obtain the compensation angle signal θ after limiting q ;

[0043] Step 120: The limited compensation angle signal θ q The phase angle output signal θ of the original phase-locked loop ori The new phase-locked angle output phase signal θ is obtained by subtracting pll ;

[0044] Step 130: Based on the new phase-locked angle signal θ pll , the upper control loop of the doubly-fed wind turbine generates a new control signal, which in turn enables the doubly-fed wind turbine to have a fast inertia response capability.

[0045] When it is detected that the q-axis voltage signal of the power grid in the two-phase rotating coordinate system is not zero, the compensation link outputs a compensation angle signal, limits the compensation angle signal and introduces the limited signal into the output phase angle signal of the original phase-locked loop, thereby enabling the doubly-fed wind turbine to provide a fast inertia response during power grid frequency disturbances and reduce the degree to which the system frequency deviates from the rated value.

[0046] Specifically, it includes: firstly, obtaining the grid q-axis voltage signal in the two-phase rotating coordinate system in real time through the phase-locked loop; secondly, obtaining the compensation angle signal through the compensation link of the grid q-axis voltage signal; and finally outputting it to the limiting link to ensure that the output is within the controllable range of the system. The output is the compensation angle signal θ described in step 120. q The compensation angle signal after limiting is θ q Add to the original phase-locked loop output phase angle signal to get the new phase-locked angle signal θ pll, the upper control of the system generates a new control signal based on the signal. Therefore, the method of the present invention can achieve the control target of fast inertia response of the doubly-fed wind turbine during frequency disturbance. It is simple and feasible, and can effectively achieve fast inertia response when frequency disturbance occurs. It can not only effectively slow down the change of system frequency without investing in any hardware device, but also continuously provide dynamic active power support.

[0047] The method for determining whether the q-axis voltage signal of the power grid in the two-phase rotating coordinate system is non-zero is specifically as follows:

[0048] like Figure 2 As shown in the figure, the main circuit topology of the doubly-fed wind turbine generator set is: Figure 2 In the figure, DFIG represents a doubly-fed wind turbine generator set, S1, S2, and S3 are the inverter drive signals of the rotor-side converter; RSC represents the rotor-side converter; U dc Indicates the DC bus voltage; I sabc Indicates the three-phase current output on the stator side, ω r represents the rotor angular velocity, θ r Rotor rotation angle. Figure 3 The improved phase-locked loop 2 of the present method shown in the figure has the following working process: collecting the stator port voltage signal V of the double-fed wind turbine connected to the power grid sabc ; Through coordinate transformation, the port voltage signal V in the three-phase stationary coordinate system is converted sabc Transformed into the port voltage V in the two-phase stationary coordinate system αβ ; Through coordinate transformation, the port voltage signal V in the two-phase stationary coordinate system is converted αβ Transformed into the port voltage V in the two-phase rotating coordinate system sd and V sq , where the coordinate transformation angle signal θ pll Provided by the phase-locked loop output phase signal; the q-axis voltage signal V sq Input the PI controller to obtain the angular frequency deviation signal ω between the system real-time angular frequency ω and the rated angular frequency ω0 err When the voltage signal of the grid q axis in the two-phase rotating coordinate system is not 0, the compensation link takes effect and the output compensation angle θ qs , the compensation angle is limited to obtain the true compensation angle signal θ added to the original phase-locked loop output phase angle q ; Angular frequency deviation signal ω err The real-time angular frequency signal ω is added to the rated angular frequency signal ω0; the real-time angular frequency signal ω is passed through the integration link to obtain the output phase signal θ of the original phase-locked loop ori , minus the compensation angle signal θ q Get the system phase angle signal reference θ pll .

[0049] In addition, if Figure 4As shown, step 130 may specifically be:

[0050] First, collect the stator port voltage signal V of the doubly fed wind turbine sabc , stator current signal I sabc , rotor current signal I rabc And the rotor position angle signal θ r :Use the above obtained θ pll The coordinate transformation is performed to convert the port voltage signal V in the three-phase stationary coordinate system sabc Transform the port voltage signal V to the two-phase rotating coordinate system sd and V sq ; Stator current signal I in three-phase stationary coordinate system sabc Transform the current signal I to the two-phase rotating coordinate system sd and I sq ; Using the phase information θ obtained above pll And the rotor position angle signal θ r Perform coordinate transformation to transform the rotor current signal I in the three-phase stationary coordinate system rabc The current signal I transformed into the two-phase rotating coordinate system rd and I rq .

[0051] Secondly, the stator voltage signal V of the doubly-fed wind turbine generator set is obtained in the two-phase rotating coordinate system. sd and V sq , stator current signal I sd and I sq , the real-time active power P can be calculated e and Q e , the active power reference command P ref and real-time active power P e Subtract the two, input the deviation into the active power PI controller and limit the output result to obtain the rotor d-axis current reference signal I rdref ; The reactive power reference signal Q ref and real-time reactive power Q e Subtract the two, input the deviation signal into the reactive power PI controller and limit the output result to obtain the rotor q-axis current reference signal I rqref .

[0052] Finally, after obtaining the rotor current d and q axis reference current instructions, I rdref ,I rqref After that, according to the rotor d-axis current command I rdref , rotor q-axis current command I rqref and the actual rotor d-axis current I rd , q-axis current I rq Perform subtraction operation to obtain the d-axis error signal Irderr , q-axis error signal I rqerr ,in, The error signal I of the d-axis rderr and the q-axis error signal I rqerr Perform closed-loop processing respectively to obtain the converter d-axis voltage demand signal V rd , converter q-axis voltage demand signal V rq ; According to the rotor d-axis current I rd and q-axis current I rq Generate d-axis feedforward signal V rdc , q-axis feedforward signal V rqc ;in, Feedforward signal V rdc 、V rqc By decoupling the feedforward term -ω2σL r I rq ω2σL r I rd and the induced electromotive force feedforward term E rd 、E rq It consists of two parts, ω2 is the slip angle, σ is the leakage inductance coefficient, L r is the rotor self-inductance, E rd is the d-axis component of the induced electromotive force on the rotor side, E rq is the q-axis component of the induced electromotive force on the rotor side; according to the feedforward signal V rdc 、V rqc and the converter d-axis voltage demand signal V rd , converter q-axis voltage demand signal V rq , get the modulated signal V rdref 、V rqref ;in, The rotor modulation signal V rdref 、V rqref According to the phase information θ pll and the rotor position angle θ r Perform inverse coordinate transformation to obtain the rotor modulation voltage in the two-phase stationary coordinate system; perform SVPWM modulation on the modulation signal in the two-phase stationary coordinate system to obtain the PWM control signals S1, S2, and S3 of the rotor-side converter switch tube.

[0053] It should be noted that the method of this embodiment takes a doubly-fed wind turbine as an example. The method of this embodiment can be used as a control system for a phase-locked loop new energy power generation equipment that performs phase angle compensation based on the q-axis voltage of the power grid in a two-phase rotating coordinate system, and includes: a sampling and processing unit 1, an improved phase-locked loop 2, a coordinate transformation unit 3, an active and reactive 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 the doubly-fed wind turbine. 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 stator and rotor voltage and current signals, motor rotor angle signals, and rotor angular velocity signals. The stator voltage measurement quantity at its output end is connected to the input end of the improved phase-locked loop 2 and the input end of the coordinate transformation unit 3; the stator current and rotor current measurement quantities at its output end are connected to the input end of the coordinate transformation unit 3; the rotor angle measurement quantity at its output end is connected to the input end of the coordinate transformation unit 3 and the space vector modulator 6; the improved 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 coordinate transformation unit 3. The input end of the conversion unit 3 and the input end of the space vector modulator 6; the active and reactive control loop 4 performs closed-loop adjustment through the reference instruction and the feedback measurement to calculate the d and q axis current reference instructions input to the rotor current control loop 5; the rotor current control loop 5 performs closed-loop adjustment through the rotor current instruction and the rotor measurement to calculate the modulation voltage signal, and its output end is connected to the modulation input end of the space vector modulator 6; 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 switch signal input end of the rotor-side converter 7.

[0054] In the embodiment of the present invention, the sampling processing unit 1 includes: a sampling unit for collecting the stator AC voltage signal V of the double-fed motor sabc , stator current signal I sabc 、Rotor AC signal I radc ; Encoder unit, used to obtain the rotor angle θ of the doubly fed motor r .

[0055] The improved phase-locked loop 2 includes: a Park coordinate transformation unit, which is used to transform the stator voltage signal V sabc Transformed into the stator d-axis voltage V in the two-phase rotating coordinate system sd , q-axis voltage V sq ; A controller unit, used to calculate the system angular frequency deviation signal according to the q-axis voltage; a compensation unit, used to generate a phase angle compensation signal according to the q-axis grid voltage; an adder unit, used to superimpose the system rated angular frequency signal to obtain the system real-time angular frequency signal; an integrator unit, used to obtain the phase angle of the grid connection point voltage by integrating the system real-time angular frequency signal; a subtractor unit, used to subtract the compensation angle from the phase angle output by the original phase-locked loop to obtain the final phase-locked angle.

[0056] The coordinate transformation unit 3 includes: a Park coordinate transformation unit, which is used to transform the stator voltage signal V sabc , stator current signal I sabc and rotor AC signal I radc Transformed into the stator dq voltage signal V in the two-phase rotating coordinate system sd and V sq , stator dq current signal I sd and I sq , rotor dq current signal I rd and I rq .

[0057] The active and reactive control loop 4 includes: a subtractor unit, which is used to make a difference between the reference signal and the feedback signal to obtain an error signal; a controller unit, in which the active controller is used to perform closed-loop processing on the active power to obtain a rotor d-axis voltage reference signal, and the reactive controller is used to perform closed-loop processing on the reactive power to obtain a rotor q-axis voltage reference signal; and an output limiting unit, which is used to ensure that the output current reference instruction does not exceed the current limit that the equipment can withstand.

[0058] The rotor current control loop 5 includes: a feedforward unit, through which the rotor d-axis current I rd , q-axis current I rq To calculate the feedforward compensation signal V rdc 、V rqc ; The 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 rderr , q-axis error I rqerr , wherein the first controller is used to convert the d-axis error signal I rderr Perform closed-loop regulation to obtain the converter d-axis voltage demand signal V rd The second controller is used to convert the q-axis error signal I rqerr Perform closed-loop regulation to obtain the converter q-axis voltage demand signal V rq ; a modulation signal generating unit, wherein the first adder is used to d-axis error signal I rdref and d-axis feedforward compensation signal V rdc Add to obtain the d-axis modulation signal V rdref The second adder is used to convert the q-axis error signal I rqerr and q-axis feedforward compensation signal V rqc Add to obtain the q-axis modulation signal V rqref .

[0059] The space vector modulator 6 is used to modulate the signal V rdref 、V rqref SVPWM modulation is performed to obtain PWM control signals S1, S2, and S3 of the rotor-side converter switch tube. The PWM control signals S1, S2, and S3 are 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.

[0060] This embodiment improves the phase-locked loop of the doubly-fed wind turbine generator set and introduces the q-axis voltage signal of the power grid, so that the doubly-fed wind turbine generator set can provide a fast inertia response. Specifically, it includes: firstly, the q-axis voltage signal of the power grid in the two-phase rotating coordinate system is obtained in real time through the phase-locked loop; secondly, the q-axis voltage signal of the power grid is passed through the compensation link to obtain the compensation angle signal; finally, the output is output to the limiting link to ensure that the output is within the controllable range of the system. The output is the compensation angle signal θ described in step 120. q The compensation angle signal after limiting is θ q Add to the original phase-locked loop output phase angle signal to get the new phase-locked angle signal θ pll , the upper control of the system generates a new control signal based on the signal. Therefore, the method of the present invention can achieve the control goal of fast inertia response of the doubly-fed wind turbine during frequency disturbance, avoids the use of differential operators that characterize the frequency change rate, is simple and feasible, and can effectively achieve fast inertia response when frequency disturbance occurs. It can not only effectively slow down the change of system frequency without investing in any hardware devices, but also continuously provide dynamic active power support.

[0061] It should be added that the compensation link of the phase-locked loop is specifically:

[0062] Based on the grid q-axis voltage signal V in the two-phase rotating coordinate system sq , the q-axis voltage signal passes through the compensation link to obtain the phase compensation angle signal θ qs ;

[0063] The compensation angle signal θ qs Limiting, get the compensation angle signal θ after limiting q , making the output phase angle of the phase-locked loop related to the grid angular frequency deviation.

[0064] It should be added that the specific form of the compensation link is:

[0065]

[0066] Where: k ipll K is the integral parameter of the phase-locked loop PI controller, F is the frequency second differential coefficient, J F is the first differential coefficient of frequency, ζ is the damping ratio of the second-order filter, ωc is the oscillation frequency of the second-order filter, V sq is the q-axis voltage signal of the power grid in the two-phase rotating coordinate system.

[0067] It should be added that the compensation link calculates the compensation angle signal θ qs A second-order filter is introduced to filter out the high-order harmonics in the grid angular frequency, so as to eliminate the high-frequency noise entering the phase-locked loop and ensure the stability of the system.

[0068] It should be added that the output limit is determined according to actual controllable needs.

[0069] Set the limit value to limit the output result within a reasonable range to prevent the output result from exceeding the control capability of the doubly-fed wind turbine generator set.

[0070] The output compensation angle signal of the grid q-axis voltage signal is introduced into the output phase angle signal of the phase-locked loop through the compensation link. Compared with other frequency support methods, it has a simple structure and strong portability, avoids the use of differential operators that deteriorate system stability, and significantly improves the rapidity of inertia response under the basic requirements of inertia response.

[0071] For example, when the grid q-axis voltage signal is not 0, the grid q-axis voltage signal V sq After the compensation link, the compensation angle signal θ is obtained qsi , the compensation link is: Where: k ipll K is the integral parameter of the phase-locked loop PI controller, F is the frequency second differential coefficient, J F is the first differential coefficient of frequency, ζ is the damping ratio of the second-order filter, ω c is the oscillation frequency of the second-order filter, V sq is the q-axis voltage signal of the power grid in the two-phase rotating coordinate system. qs Limiting, get the compensation angle signal θ after limiting q ; The compensation angle signal after limiting θ q The original phase-locked loop output phase angle signal θ ori Subtract and get the new phase information θ pll , and reclose the system loop.

[0072] In order to better illustrate the effect of the method of this embodiment, an experimental study is conducted by taking a wind farm composed of 100 1.5MW typical double-fed wind turbines as an example. Before the fault occurs, the system frequency is the rated frequency, and the double-fed wind turbines output a stable power of 0.7pu. At 6s, the system suddenly increases the load. The output active power of the double-fed wind turbines, the system frequency, and the system frequency change rate obtained by using other inertia control methods and the inertia control method proposed in this embodiment are as follows: Figure 5 As shown, Figure 6 The middle one is the experimental result diagram corresponding to the inertia control method that uses the system angular frequency deviation to obtain the phase compensation angle through the first-order inertia and differential link to feed forward to the phase angle of the phase-locked loop; Figure 7 and 8 The figure is the experimental result corresponding to the inertia control method proposed in this embodiment. Comparing the two figures, it can be seen that the maximum active power increase of both during the frequency disturbance is 0.08pu, but the time to reach the peak active power by the inertia control method proposed in this embodiment is increased by 1s, which means that the rapidity of the inertia response is significantly improved. At the same time, the system frequency change rate corresponding to the inertia control method proposed in this embodiment is reduced to a certain extent in the initial stage.

[0073] Embodiment 2

[0074] A method for controlling a power grid frequency by a double-fed wind turbine generator set, comprising:

[0075] The q-axis voltage signal V of the power grid in the two-phase rotating coordinate system is obtained in real time through the phase-locked loop sq , which is obtained by the Park transformation link output of the double-fed wind turbine phase-locked loop;

[0076] A new phase-locked loop signal θ is obtained by using a fast inertia response control method of a doubly-fed wind turbine generator set to the grid frequency as in the above embodiment 1. pll ;

[0077] Based on the new phase-locked loop signal θ pll , vector control is adopted to control the double-fed wind turbine to output active power to the grid and realize rapid inertia response to the grid frequency.

[0078] By adopting the improved phase-locked loop as described above, the q-axis voltage signal of the power grid in the two-phase rotating coordinate system is obtained, and the compensation angle signal obtained through the compensation link and the limiting link is subtracted from the original phase angle signal of the phase-locked loop to obtain a coordinate transformation angle signal that takes into account the power grid frequency disturbance and is used in the vector control of the equipment power transmission. This method of bottom-level control, on the one hand, enables the power generation equipment to actively support the power grid frequency, and on the other hand, can achieve stable and reliable power generation tasks. It can be applied to wind turbines, photovoltaic systems and other similar various new energy power generation equipment and is simple and feasible.

[0079] The relevant technical solution is the same as that in Embodiment 1 and will not be described in detail here.

[0080] Embodiment 3

[0081] A storage medium having instructions stored therein, wherein when a computer reads the instructions, the computer is caused to execute any one of the methods for controlling the fast inertia response of a doubly-fed wind turbine set to a grid frequency as described in the first embodiment and / or a control system for the grid frequency of a doubly-fed wind turbine set as described in the second embodiment.

[0082] The relevant technical solutions are the same as those in Embodiment 1 and Embodiment 2 and will not be described in detail here.

[0083] It will be easily understood by those skilled in the art that 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 in the protection scope of the present invention.

Claims

1. A fast inertia response control method for a doubly-fed wind turbine generator set to a grid frequency, characterized in that: include: Step S110: Obtain the grid q-axis voltage signal V in the two-phase rotating coordinate system in real time through a phase-locked loop sq , the grid q-axis voltage signal V sq After the compensation link, the phase compensation angle signal θ is obtained qs And limit the amplitude to obtain the compensation angle signal θ after limiting q ; Step S120: The limited compensation angle signal θ q The phase angle output signal θ of the original phase-locked loop ori The new phase-locked angle output phase signal θ is obtained by subtracting pll ; Step S130: Based on the new phase-locking angle signal θ pll , the upper control loop of the doubly-fed wind turbine generates a new control signal, which in turn enables the doubly-fed wind turbine to have a fast inertia response capability.

2. A method for controlling the fast inertia response of a doubly-fed wind turbine to a grid frequency according to claim 1, characterized in that: The compensation process in step S110 is specifically as follows: Based on the grid q-axis voltage signal V in the two-phase rotating coordinate system sq , the phase compensation angle signal θ is obtained through the relationship between active power, phase-locked loop, primary frequency change rate and secondary frequency change rate qs ; Based on the phase compensation angle signal θ qs , the compensation angle signal is limited to obtain the compensation angle signal θ after limiting q , used to make a difference with the original phase angle output signal of the phase-locked loop.

3. A method for controlling the fast inertia response of a doubly-fed wind turbine to a grid frequency according to claim 1 or 2, characterized in that: The compensation angle signal in the phase-locked loop is: Where: k ipll K is the integral parameter of the phase-locked loop PI controller, F is the frequency second differential coefficient, J F is the first differential coefficient of frequency, ζ is the damping ratio of the second-order filter, ω c is the oscillation frequency of the second-order filter, V sq is the q-axis voltage signal of the power grid in the two-phase rotating coordinate system.

4. The method for controlling the fast inertia response of a doubly-fed wind turbine generator set to a grid frequency according to claim 1, characterized in that: The compensation angle signal θ qs After limiting, we get θ q , and the limited compensation angle signal θ q The original phase signal θ output by the phase-locked loop ori Subtract and get a new phase-locked loop signal θ pll .

5. A doubly-fed wind turbine control method, characterized in that: include: The q-axis voltage signal V of the power grid in the two-phase rotating coordinate system is obtained in real time through the phase-locked loop sq , which is obtained by the Park transformation link output of the double-fed wind turbine phase-locked loop; A new phase-locked loop signal θ is obtained by using a fast inertia response control method for a double-fed wind turbine generator set to a grid frequency according to any one of claims 1 to 4. pll ; Based on the new phase-locked loop signal θ pll , vector control is adopted to control the double-fed wind turbine to output active power to the grid and realize rapid inertia response to the grid frequency.

6. A storage medium, characterized in that: The storage medium stores instructions, and when the computer reads the instructions, the computer executes the method for fast inertia response control of a doubly-fed wind turbine set to grid frequency as described in any one of claims 1 to 4 and / or the method for controlling a doubly-fed wind turbine set as described in claim 5.

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