Voltage coordination control method and device for network construction type wind power plant

Abstract

The invention discloses a voltage coordination control method and device for a network construction type wind power plant, and the method comprises the steps: obtaining a corresponding fundamental wave positive sequence voltage based on the collected voltage of a grid-connected point of a wind turbine generator, and obtaining a corresponding reactive power reference value and an active power reference value based on the fundamental wave positive sequence voltage; obtaining an active power output value of the converter, and obtaining a corresponding phase angle based on the active power reference value and the active power output value; obtaining a corresponding virtual inductance value based on the fundamental wave positive sequence voltage, and obtaining a corresponding d-axis voltage modulation quantity and a q-axis voltage modulation quantity based on the virtual inductance value; and determining a three-phase voltage modulation quantity based on the d-axis voltage modulation quantity, the q-axis voltage modulation quantity and the phase angle, and controlling the output voltage of the converter based on the three-phase voltage modulation quantity. According to the invention, the uniformity of reactive power distribution among the units of the grid-forming wind power plant and the safe operation of the units can be ensured.

Description

Technical Field

[0001] The present application relates to the field of power grid control, and in particular to a voltage coordination control method and device for a grid-connected wind farm. Background Art

[0002] The inherent random volatility of wind power, the "grid decoupling" characteristics of the power electronic topology, and the variable nature over time scales have jointly led to the weakening of the anti-disturbance ability of the power system. When wind power is integrated into the regional power grid on a large scale, this weakening effect will affect the stability of the power grid operation. At the same time, since wind turbines lack a frequency modulation mechanism that responds to the frequency of the power system and fail to fully utilize their reactive voltage control capabilities, they not only limit the regulation and anti-disturbance capabilities of the power system after wind power access, but also affect the frequency stability and voltage stability of the power system.

[0003] In response to the above dilemma, scholars at home and abroad have proposed grid-connected wind turbine control schemes to solve the problem of stable operation of wind turbines in weak power grids. However, the grid-connected wind turbine control scheme is difficult to solve the problem of reactive power distribution between parallel converters caused by output impedance or line impedance mismatch, which in turn affects the safe operation of each unit.

[0004] Application Contents

[0005] The present application provides a voltage coordination control method and device for a grid-type wind farm, so as to ensure the uniformity of reactive power distribution between various units in the grid-type wind farm and ensure that each unit can operate safely.

[0006] In a first aspect, the present application provides a voltage coordination control method for a grid-connected wind farm, comprising:

[0007] Obtaining a corresponding fundamental positive-sequence voltage based on the collected wind turbine grid connection point voltage, and obtaining a corresponding reactive power reference value and an active power reference value based on the fundamental positive-sequence voltage;

[0008] Acquire an active power output value of the converter, and obtain a corresponding phase angle based on the active power reference value and the active power output value;

[0009] Obtaining a corresponding virtual inductance value based on the fundamental positive-sequence voltage, and obtaining a corresponding d-axis voltage modulation amount and a q-axis voltage modulation amount based on the virtual inductance value;

[0010] Based on the d-axis voltage modulation amount, the q-axis voltage modulation amount and the phase angle, a three-phase voltage modulation amount is determined, and based on the three-phase voltage modulation amount, the output voltage of the converter is controlled.

[0011] The embodiment of the present application calculates the corresponding reactive power reference value and active power reference value through the fundamental positive sequence voltage, which facilitates the subsequent distribution of reactive power between the units of the grid-type wind farm based on the reactive power reference value and the reasonable setting of the reactive voltage droop coefficient of each wind turbine, thereby ensuring the uniformity of reactive power distribution between the units of the grid-type wind farm, and also helps to control the output voltage of the converter in the subsequent process; by introducing the product of the AC current and the virtual impedance into the external AC voltage control loop, and by calculating the phase angle, the d-axis voltage modulation amount and the q-axis voltage modulation amount, and by accurately converting the d-axis voltage modulation amount and the q-axis voltage modulation amount into the three-phase voltage modulation amount, and adjusting the output voltage of the converter, it can play a role in oscillation suppression, thereby ensuring that each unit can operate safely.

[0012] Furthermore, a corresponding reactive power reference value is obtained based on the fundamental positive sequence voltage, specifically:

[0013] Acquire the rated apparent power of the wind turbine generator set, and obtain the allowable apparent power of the wind turbine generator set based on the rated apparent power and the fundamental positive sequence voltage;

[0014] Based on the fundamental positive-sequence voltage and the allowable apparent power, a corresponding reactive power reference value is obtained.

[0015] In this way, the corresponding reactive power reference value is calculated by the fundamental positive sequence voltage, which facilitates the subsequent distribution of reactive power among the units in the grid-type wind farm based on the reactive power reference value and the reasonable setting of the reactive voltage droop coefficient of each wind turbine, thereby ensuring the uniformity of reactive power distribution among the units in the grid-type wind farm.

[0016] Furthermore, the calculation formula for obtaining the corresponding reactive power reference value based on the fundamental positive sequence voltage and the allowable apparent power is specifically:

[0017]

[0018] In the formula, Q * is the reactive power reference value, K is the reactive power adjustment coefficient, V FM is the fundamental positive sequence voltage, V N is the voltage rating of the wind turbine grid connection point, S new It is the allowable apparent power of wind turbines in the power grid.

[0019] Further, the corresponding phase angle is obtained based on the active power reference value and the active power output value, specifically:

[0020] Obtaining a first output value based on the active power reference value and the active power output value;

[0021] Performing inertia simulation on the first output value to obtain an angular frequency adjustment amount;

[0022] Based on the acquired rated angular frequency of the wind turbine generator set and the angular frequency adjustment amount, the actual angular frequency of the wind turbine generator set is obtained, and based on the actual angular frequency, the corresponding phase angle is obtained.

[0023] In this way, by calculating the phase angle, it is convenient to subsequently convert the d-axis voltage modulation amount and the q-axis voltage modulation amount into a three-phase voltage modulation amount.

[0024] Furthermore, the calculation formula for obtaining the corresponding virtual inductance value based on the fundamental positive sequence voltage is specifically:

[0025]

[0026] Where, L v is the virtual inductance value, V FM is the fundamental positive sequence voltage, E is the internal potential voltage vector, ω is the actual angular frequency, I max is the AC current limit value of the wind turbine converter, L r is the actual inductance of the output filter, K is the reactive power adjustment coefficient, V FM is the fundamental positive sequence voltage, V N is the voltage rating of the wind turbine grid connection point, I N is the rated output current of the wind turbine.

[0027] Furthermore, before obtaining the corresponding q-axis voltage modulation amount and d-axis voltage modulation amount based on the virtual inductance, the method further includes:

[0028] Obtaining a reactive power output value of the converter, and obtaining a corresponding voltage regulation amount based on the reactive power reference value, the reactive power output value and a preset droop coefficient, wherein the droop coefficient is determined according to the impedance of each unit in the wind farm to the grid connection point;

[0029] The voltage amplitude of the converter grid-connected point is obtained, and based on the voltage adjustment amount and the voltage amplitude, a corresponding control voltage reference value is obtained.

[0030] In this way, the control voltage reference value can be accurately calculated based on the reactive power reference value, which is convenient for the subsequent distribution of reactive power among the units in the grid-type wind farm based on the reactive power reference value and the reasonable setting of the reactive voltage droop coefficient of each wind turbine, thereby ensuring the uniformity of reactive power distribution among the units in the grid-type wind farm, and also helps in the subsequent calculation of the d-axis voltage modulation amount, thereby facilitating the conversion into a three-phase voltage modulation amount.

[0031] Furthermore, the corresponding d-axis voltage modulation amount is obtained based on the virtual inductance, specifically:

[0032] Obtaining a corresponding output current q-axis component and an output current d-axis component based on the collected wind turbine grid-connected point current, and obtaining a corresponding d-axis voltage reference value based on the output current q-axis component, the virtual inductance value and the control voltage reference value;

[0033] Acquire a d-axis voltage component of a converter grid-connected point, and obtain a corresponding d-axis current inner loop reference value based on the d-axis voltage reference value and the d-axis voltage component;

[0034] Based on the d-axis current inner loop reference value and the output current d-axis component, obtaining a corresponding d-axis control voltage;

[0035] Based on the d-axis voltage component, the d-axis control voltage and the q-axis cross-coupling amount, the corresponding d-axis voltage modulation amount is obtained.

[0036] In this way, by calculating the d-axis voltage modulation amount, it is helpful to subsequently accurately convert the d-axis voltage modulation amount and the q-axis voltage modulation amount into a three-phase voltage modulation amount.

[0037] Furthermore, the corresponding q-axis voltage modulation amount obtained based on the virtual inductance is specifically:

[0038] Obtaining a corresponding output current q-axis component and an output current d-axis component based on the collected wind turbine grid-connected point current, and obtaining a corresponding q-axis voltage reference value based on the output current d-axis component and the virtual inductance value;

[0039] Acquire a q-axis voltage component of a converter grid-connected point, and obtain a corresponding q-axis current inner loop reference value based on the q-axis voltage reference value and the q-axis voltage component;

[0040] Based on the q-axis current inner loop reference value and the output current q-axis component, obtaining a corresponding q-axis control voltage;

[0041] Based on the q-axis voltage component, the q-axis control voltage and the d-axis cross-coupling amount, the corresponding q-axis voltage modulation amount is obtained.

[0042] In this way, by calculating the q-axis voltage modulation amount, it is helpful to subsequently accurately convert the q-axis voltage modulation amount and the q-axis voltage modulation amount into a three-phase voltage modulation amount.

[0043] Furthermore, the three-phase voltage modulation amount is determined by DQ / ABC transformation, wherein the calculation formula of the DQ / ABC transformation is specifically:

[0044]

[0045] In the formula, is the three-phase voltage modulation, θ is the phase angle, M dg is the d-axis voltage modulation, M qg is the q-axis voltage modulation amount.

[0046] In a second aspect, the present application provides a voltage coordination control device for a grid-type wind farm, comprising: an acquisition module, a first calculation module, a second calculation module and a control module;

[0047] The acquisition module is used to obtain the corresponding fundamental positive sequence voltage based on the collected wind turbine grid connection point voltage, and obtain the corresponding reactive power reference value and active power reference value based on the fundamental positive sequence voltage;

[0048] The first calculation module is used to obtain the active power output value of the converter, and obtain the corresponding phase angle based on the active power reference value and the active power output value;

[0049] The second calculation module is used to obtain a corresponding virtual inductance value based on the fundamental positive sequence voltage, and obtain a corresponding d-axis voltage modulation amount and a q-axis voltage modulation amount based on the virtual inductance value;

[0050] The control module is used to determine the three-phase voltage modulation amount based on the d-axis voltage modulation amount, the q-axis voltage modulation amount and the phase angle, and control the output voltage of the converter based on the three-phase voltage modulation amount.

[0051] The embodiment of the present application calculates the corresponding reactive power reference value and active power reference value through the fundamental positive sequence voltage, which facilitates the subsequent distribution of reactive power between the units of the grid-type wind farm based on the reactive power reference value and the reasonable setting of the reactive voltage droop coefficient of each wind turbine, thereby ensuring the uniformity of reactive power distribution between the units of the grid-type wind farm, and also helps to control the output voltage of the converter in the subsequent process; by introducing the product of the AC current and the virtual impedance into the external AC voltage control loop, and by calculating the phase angle, the d-axis voltage modulation amount and the q-axis voltage modulation amount, and by accurately converting the d-axis voltage modulation amount and the q-axis voltage modulation amount into the three-phase voltage modulation amount, and adjusting the output voltage of the converter, it can play a role in oscillation suppression, thereby ensuring that each unit can operate safely. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the circuit relationship after the wind turbine generator set provided by the present application is connected to the grid;

[0053] Figure 2 It is a flow chart of an embodiment of a voltage coordination control method for a grid-type wind farm provided by the present application;

[0054] Figure 3It is a schematic diagram of the calculation of the control voltage reference value provided by the present application;

[0055] Figure 4 It is a schematic diagram of droop control of a wind turbine provided in this application;

[0056] Figure 5 It is a schematic diagram for calculating the d-axis voltage modulation amount and the q-axis voltage modulation amount provided by the present application;

[0057] Figure 6 It is a structural schematic diagram of an embodiment of a voltage coordination control device for a grid-type wind farm provided in the present application. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0059] It should be understood that the step numbers used in this article are only for the convenience of description and are not intended to limit the order in which the steps are executed.

[0060] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0061] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0062] The term "and / or" means and includes any and all possible combinations of one or more of the associated listed items.

[0063] The inherent random volatility of wind power, the decoupling characteristics of the power grid, and the variable nature over time scales have led to a weakening of the anti-interference ability of the power system. The integration of large-scale wind power into the regional power grid has affected the stability of the power grid. At the same time, wind turbines lack the ability to regulate frequency and reactive voltage control, which not only limits the regulation and anti-interference capabilities of the system, but also affects the frequency stability and voltage stability of the power system. At present, some scholars have proposed a grid-type wind turbine control scheme to solve the stability problem of wind turbines in weak power grids, but the grid-type wind turbine control scheme is difficult to solve the problem of reactive power distribution between parallel converters caused by output impedance or line impedance mismatch, which in turn affects the safe operation of each unit.

[0064] Based on this, the embodiment of the present application provides a voltage coordination control method and device for a grid-type wind farm, which can ensure the uniformity of reactive power distribution between the units in the grid-type wind farm and ensure that each unit can operate safely.

[0065] A voltage coordination control method and device for a grid-type wind farm provided in an embodiment of the present application are specifically described through the following embodiments. First, the voltage coordination control method for a grid-type wind farm in an embodiment of the present application is described.

[0066] The voltage coordination control method of the grid-type wind farm provided in the embodiment of the present application relates to the field of power system communication. The voltage coordination control method of the grid-type wind farm provided in the embodiment of the present application can be applied to the terminal, can also be applied to the server side, and can also be software running in the terminal or the server side. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, etc.; the server side can be configured as an independent physical server, or it can be configured as a server cluster or a distributed system composed of multiple physical servers, and can also be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application that implements a component selection recommendation method, etc., but is not limited to the above forms.

[0067] The present application can also be used in numerous general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, etc. The present application can be described in the general context of computer executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0068] Before introducing the voltage coordination control method scheme of the grid-type wind farm, this application provides Figure 1 To roughly describe the circuit relationship after the wind turbine is connected to the grid to facilitate the understanding of the subsequent technical solutions, it can be understood that the wind farm unit is composed of multiple wind turbines, each unit includes key components such as wind turbines and generators; then the power generated by the wind farm unit needs to be converted into a form suitable for grid access through a converter; after the converter converts the power into a form suitable for grid access, the wind farm unit can be connected to the grid through the interface point where the wind farm unit is connected to the grid, that is, the grid connection point; because the power generated by the wind farm unit is at a low voltage level, it also needs to be boosted to a suitable voltage level through a step-up transformer before it can be connected to the grid. It should be noted that the actual circuit for the wind farm unit to be connected to the grid may be more complicated, and will include more electrical equipment, protection devices and wiring.

[0069] Embodiment 1

[0070] Please refer to Figure 2 , Figure 2 It is a flow chart of an embodiment of a voltage coordination control method for a grid-type wind farm provided by the present application, including steps S101 to S104;

[0071] Step S101, obtaining a corresponding fundamental positive-sequence voltage based on the collected wind turbine grid connection point voltage, and obtaining a corresponding reactive power reference value and an active power reference value based on the fundamental positive-sequence voltage;

[0072] It is understandable that the grid connection point voltage can be collected from the grid connection point of the wind turbine generator set by a voltage measuring device, wherein the grid connection point voltage is usually a three-phase AC voltage, which includes a fundamental component, a harmonic component, and a possible negative sequence component. After the grid connection point voltage of the wind turbine generator set is collected, it is necessary to extract the fundamental component in the three-phase AC voltage to facilitate the subsequent calculation of the fundamental positive sequence voltage. Specifically, first, the grid connection point voltage can be filtered by, but not limited to, an analog filter or a digital filter to remove high-order harmonics and other unnecessary frequency components; secondly, since the grid connection point voltage may contain positive and negative sequence components, it can be separated by, but not limited to, a symmetrical component method or a method based on synchronous coordinate transformation to obtain a positive sequence component; finally, it can be further extracted by, but not limited to, a low-pass filter or a band-pass filter. After the positive-sequence fundamental component in the grid connection point voltage is extracted, the effective value (RMS value) of the positive-sequence fundamental component can be calculated to obtain the fundamental positive sequence voltage V FM It should be noted that the fundamental component of the grid-connected point voltage is extracted and the fundamental positive sequence voltage V is calculated. FM All of these can be achieved through existing technologies, which are not the focus of this application and will not be elaborated here.

[0073] When the fundamental positive sequence voltage V corresponding to the grid connection point voltage is obtained FM After that, it is necessary to calculate the corresponding reactive power reference value and active power reference value based on the drop depth of the fundamental positive sequence voltage. The process of calculating the reactive power reference value is as follows: Get the rated apparent power S of the wind turbine n , and based on the rated apparent power S n With the fundamental positive sequence voltage V FM , and obtain the allowable apparent power S of the wind turbine new , the calculation formula is S new =V FM S n , where S n is the rated apparent power, V FM is the fundamental positive sequence voltage; based on the fundamental positive sequence voltage V FM and the permissible apparent power S new , get the corresponding reactive power reference value Q * , the calculation formula is:

[0074]

[0075] In the formula, Q * is the reactive power reference value, K is the reactive power adjustment coefficient, V FM is the fundamental positive sequence voltage, V N is the voltage rating of the wind turbine grid connection point, S newIt is the allowable apparent power of wind turbines in the power grid.

[0076] In this way, the corresponding reactive power reference value is calculated by the fundamental positive sequence voltage, which facilitates the subsequent distribution of reactive power among the units in the grid-type wind farm based on the reactive power reference value and the reasonable setting of the reactive voltage droop coefficient of each wind turbine, thereby ensuring the uniformity of reactive power distribution among the units in the grid-type wind farm.

[0077] Among them, the reactive power reference value P is calculated * The process is as follows: Based on the above-obtained allowable apparent power S new With the reactive power reference value Q * , the active power reference value P can be calculated * , the calculation formula is: In the formula, S new is the allowable apparent power, Q * is the reactive power reference value.

[0078] It should be noted that the rated voltage and rated current of the wind turbine can be obtained through the existing technology, and then the rated apparent power S of the wind turbine can be obtained through the rated voltage and rated current. new .

[0079] Step S102: acquiring an active power output value of the converter, and obtaining a corresponding phase angle based on the active power reference value and the active power output value;

[0080] It can be understood that when the active power reference value P is obtained * After that, the corresponding phase angle θ can be determined. Specifically, first, the actual active power output value P of the converter can be obtained by direct measurement or parameter calculation, but is not limited to; second, the active power reference value P * Subtract the active power output value P to obtain a first output value; again, perform an inertia simulation link on the first output value to obtain an angular frequency adjustment value Δω, wherein the expression of the inertia simulation link is: 1 / (Js+D), wherein J is the inertia time constant, D is the damping coefficient, and s is a complex frequency variable; finally, based on the obtained rated angular frequency ω0 of the wind turbine set and the angular frequency adjustment value Δω, the actual angular frequency ω of the wind turbine set is obtained, and the actual angular frequency ω is passed through an integration link to obtain a corresponding phase angle θ, wherein the expression of the integration link is: 1 / s, wherein s is a complex frequency variable.

[0081] It should be noted that both the inertial simulation link and the integration link can be implemented through existing technologies and are not the focus of this application, so they will not be expanded here.

[0082] In this way, by calculating the phase angle, it is convenient to subsequently convert the d-axis voltage modulation amount and the q-axis voltage modulation amount into a three-phase voltage modulation amount.

[0083] Step S103, obtaining a corresponding virtual inductance value based on the fundamental positive-sequence voltage, and obtaining a corresponding d-axis voltage modulation amount and a q-axis voltage modulation amount based on the virtual inductance value;

[0084] It can be understood that after the actual angular frequency ω is determined, the actual inductance value L of the output filter can be obtained based on the prior art. r , the internal potential voltage vector E and other values ​​are calculated to obtain the corresponding virtual inductance value L v , wherein the output filter is provided at the output port of the wind turbine converter, wherein the virtual inductance value L v The specific calculation formula is:

[0085]

[0086] Where, L v is the virtual inductance value, V FM is the fundamental positive sequence voltage, E is the internal potential voltage vector, ω is the actual angular frequency, I max is the AC current limit value of the wind turbine converter, L r is the actual inductance of the output filter, K is the reactive power adjustment coefficient, V N is the voltage rating of the wind turbine grid connection point, I N is the rated output current of the wind turbine.

[0087] Since the d-axis voltage modulation amount M is calculated in the subsequent dg The control voltage reference value V of the inverter grid connection point is required in the process * Therefore, it is necessary to calculate the control voltage reference value V of the inverter grid connection point first. * , where the control voltage reference value V * The calculation process is as follows: First, the reactive power output value Q of the converter can be obtained by direct measurement or parameter calculation method, but is not limited to, and the reactive power reference value Q is converted to * The reactive power output value Q is multiplied by a preset droop coefficient kqi to obtain a corresponding voltage regulation amount ΔV, wherein the droop coefficient kqi is determined according to the impedance of each unit in the wind farm to the grid connection point, wherein the droop coefficient kqi needs to satisfy: In the formula, K q1 ,K q2 ,...K qn are the droop coefficients of units 1, 2, ....n, respectively, X L1 ,X L2 ...X Lnare the impedances of each unit in the wind farm to the grid connection point respectively; finally, the voltage amplitude V of the converter grid connection point is obtained, and based on the sum of the voltage adjustment amount ΔV and the voltage amplitude V, the corresponding control voltage reference value V is obtained. * Among them, the schematic diagram of the control voltage reference value calculation is as follows Figure 3 shown.

[0088] It should be noted that when the droop coefficient is set to When the voltage between the converters of each wind turbine is equal, the voltage distribution can be guaranteed to be uniform. Figure 4 The wind turbine droop control schematic diagram is used as an example to explain the reactive power distribution principle and the idea of ​​determining the droop coefficient. Figure 4 As shown in (a), it is assumed that there are two parallel grid-connected converters GFM1 and GFM2. Figure 4 The QV droop control shown in (b) can obtain the expression of the output voltage V of the two converters: Where V M1 and V M2 are the output voltages of GFM1 and GFM2 respectively, k1 and k2 represent the droop coefficients, Figure 4 (a) It can be seen that V and V PCC The relationship is: Since X>>R, ignoring the line resistance R, we have: When the droop factor is set to: When V M1 =V M2 , then the voltage drops of the two units are equal, and the terminal voltages are equal, thus ensuring uniform voltage distribution.

[0089] In this way, the control voltage reference value can be accurately calculated based on the reactive power reference value, which is convenient for the subsequent distribution of reactive power among the units in the grid-type wind farm based on the reactive power reference value and the reasonable setting of the reactive voltage droop coefficient of each wind turbine, thereby ensuring the uniformity of reactive power distribution among the units in the grid-type wind farm, and also helps in the subsequent calculation of the d-axis voltage modulation amount, thereby facilitating the conversion into a three-phase voltage modulation amount.

[0090] It can be understood that based on the virtual inductance value L v Get the corresponding d-axis voltage modulation M dg The process is as follows: First, the corresponding output current q-axis component I is obtained based on the collected wind turbine grid-connected point current gqpu and the output current d-axis component I gdpu , and based on the output current q-axis component I gqpu , the virtual inductance value L v and the control voltage reference value V *, get the corresponding d-axis voltage reference value Wherein, the virtual inductance value L v The q-axis component of the output current I gqpu Multiply to get the virtual impedance voltage drop V ZVD , after which the virtual impedance voltage drop V ZVD With the control voltage reference value V * Add to get the d-axis voltage reference value Secondly, obtain the d-axis voltage component V at the grid-connected point of the converter gdpu , and based on the d-axis voltage reference value and the d-axis voltage component V gdpu That is, the d-axis voltage reference value The d-axis voltage component V at the point where the converter is connected to the grid gdpu The corresponding d-axis current inner loop reference value is obtained by the PI controller. Again, based on the d-axis current inner loop reference value and the output current d-axis component I gdpu That is, the d-axis current inner loop reference value The d-axis component of the output current I gdpu The corresponding d-axis control voltage V is obtained by the PI controller. d Finally, based on the d-axis voltage component V gdpu , the d-axis control voltage V d The d-axis voltage modulation M is obtained by cross-coupling with the q-axis. dg , where the output current q-axis component I gqpu With the preset amount L eqpu It can be understood that based on the virtual inductance value L v Get the corresponding q-axis voltage modulation M qg Specifically, first, based on the collected wind turbine grid-connected point current, the corresponding output current q-axis component I is obtained. gqpu and the output current d-axis component I gdpu , and based on the output current d-axis component I gdpu and the virtual inductance value L v , get the corresponding q-axis voltage reference value Wherein, the virtual inductance value L v The d-axis component of the output current I gdpu Multiply to get the virtual impedance voltage drop V ZVD , after 0 with the virtual impedance drop V ZVD Subtract and get the q-axis voltage reference value Secondly, obtain the q-axis voltage component V at the grid-connected point of the converter gqpu, and based on the q-axis voltage reference value and the q-axis voltage component V gqpu That is, the q-axis voltage reference value With the q-axis voltage component V gqpu The corresponding q-axis current inner loop reference value is obtained by the PI controller. Again, based on the q-axis current inner loop reference value and the output current q-axis component I gqpu That is, the q-axis current inner loop reference value The q-axis component of the output current I gqpu The corresponding q-axis control voltage V is obtained by the PI controller. q Finally, based on the q-axis voltage component V gqpu , the q-axis control voltage V q The q-axis voltage modulation M is obtained by cross-coupling the d-axis voltage qg , where the output current d-axis component I gdpu With the preset amount L eqpu The d-axis cross coupling is obtained by multiplying them. The calculation diagram of the d-axis voltage modulation and the q-axis voltage modulation is shown in the figure. Figure 5 shown.

[0091] In this way, by calculating the d-axis voltage modulation amount and the q-axis voltage modulation amount, it is helpful to subsequently accurately convert the d-axis voltage modulation amount and the q-axis voltage modulation amount into a three-phase voltage modulation amount.

[0092] Step S104: determine the three-phase voltage modulation amount based on the d-axis voltage modulation amount, the q-axis voltage modulation amount and the phase angle, and control the output voltage of the converter based on the three-phase voltage modulation amount.

[0093] It can be understood that when the d-axis voltage modulation M is obtained dg and q-axis voltage modulation M qg After that, it is necessary to transform it to obtain the three-phase voltage modulation amount, wherein the three-phase voltage modulation amount can be determined by, but not limited to, DQ / ABC transformation, wherein the calculation formula of the DQ / ABC transformation is specifically:

[0094]

[0095] In the formula, is the three-phase voltage modulation, θ is the phase angle, M dg is the d-axis voltage modulation, M qg is the q-axis voltage modulation amount.

[0096] It can be understood that after the three-phase voltage modulation amount is determined, a pulse generator is required to generate a converter trigger pulse, and by controlling the opening and closing of the converter switch tube, the converter three-phase output voltage target value is controlled, thereby achieving control of the converter output voltage.

[0097] It should be noted that the DQ / ABC transformation is a coordinate transformation method, which is mainly used to convert the AC quantity in the three-phase stationary coordinate system (ABC coordinate system) into the DC quantity in the two-phase rotating coordinate system (dq coordinate system) (DQ transformation), or to convert the DC quantity in the two-phase rotating coordinate system (dq coordinate system) back to the AC quantity in the three-phase stationary coordinate system (ABC coordinate system) (ABC transformation).

[0098] The embodiment of the present application calculates the corresponding reactive power reference value and active power reference value through the fundamental positive sequence voltage, which facilitates the subsequent distribution of reactive power between the units of the grid-type wind farm based on the reactive power reference value and the reasonable setting of the reactive voltage droop coefficient of each wind turbine, thereby ensuring the uniformity of reactive power distribution between the units of the grid-type wind farm, and also helps to control the output voltage of the converter in the subsequent process; by introducing the product of the AC current and the virtual impedance into the external AC voltage control loop, and by calculating the phase angle, the d-axis voltage modulation amount and the q-axis voltage modulation amount, and by accurately converting the d-axis voltage modulation amount and the q-axis voltage modulation amount into the three-phase voltage modulation amount, and adjusting the output voltage of the converter, it can play a role in oscillation suppression, thereby ensuring that each unit can operate safely.

[0099] Embodiment 2

[0100] Please refer to Figure 6 , Figure 6 It is a structural schematic diagram of an embodiment of a voltage coordination control device for a grid-type wind farm provided by the present application; it includes: an acquisition module 100, a first calculation module 200, a second calculation module 300 and a control module 400;

[0101] The acquisition module 100 is used to obtain the corresponding fundamental positive sequence voltage based on the collected wind turbine grid connection point voltage, and obtain the corresponding reactive power reference value and active power reference value based on the fundamental positive sequence voltage;

[0102] The first calculation module 200 is used to obtain the active power output value of the converter, and obtain the corresponding phase angle based on the active power reference value and the active power output value;

[0103] The second calculation module 300 is used to obtain a corresponding virtual inductance value based on the fundamental positive sequence voltage, and obtain a corresponding d-axis voltage modulation amount and a q-axis voltage modulation amount based on the virtual inductance value;

[0104] The control module 400 is used to determine the three-phase voltage modulation amount based on the d-axis voltage modulation amount, the q-axis voltage modulation amount and the phase angle, and control the output voltage of the converter based on the three-phase voltage modulation amount.

[0105] Since the information interaction, execution process, etc. between the modules in the voltage coordination control device of the above-mentioned grid-type wind farm are based on the same concept as the embodiment of the voltage coordination control method of the grid-type wind farm in the first aspect of the present invention, the technical effects achieved are basically the same. For specific contents, please refer to the description in the first embodiment of the method of the present invention, and will not be repeated here.

[0106] The device embodiments described above are merely illustrative, wherein the modules described as separate components may or may not be physically separated, i.e., may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the method of this embodiment.

[0107] The present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the voltage coordination control method for a grid-type wind farm as described in the first embodiment above is implemented.

[0108] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-monitorable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0109] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application.

[0110] It is particularly pointed out that for those skilled in the art, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application should be included in the protection scope of this application.

Claims

1. A voltage coordination control method for a grid-type wind farm, characterized in that: include: Obtaining a corresponding fundamental positive-sequence voltage based on the collected wind turbine grid connection point voltage, and obtaining a corresponding reactive power reference value and an active power reference value based on the fundamental positive-sequence voltage; Acquire an active power output value of the converter, and obtain a corresponding phase angle based on the active power reference value and the active power output value; Obtaining a corresponding virtual inductance value based on the fundamental positive-sequence voltage, and obtaining a corresponding d-axis voltage modulation amount and a q-axis voltage modulation amount based on the virtual inductance value; Based on the d-axis voltage modulation amount, the q-axis voltage modulation amount and the phase angle, a three-phase voltage modulation amount is determined, and based on the three-phase voltage modulation amount, the output voltage of the converter is controlled.

2. The voltage coordination control method of a grid-type wind farm according to claim 1, characterized in that: The corresponding reactive power reference value is obtained based on the fundamental positive sequence voltage, specifically: Acquire the rated apparent power of the wind turbine generator set, and obtain the allowable apparent power of the wind turbine generator set based on the rated apparent power and the fundamental positive sequence voltage; Based on the fundamental positive-sequence voltage and the allowable apparent power, a corresponding reactive power reference value is obtained.

3. The voltage coordination control method of a grid-type wind farm according to claim 2, characterized in that: The calculation formula for obtaining the corresponding reactive power reference value based on the fundamental positive sequence voltage and the allowable apparent power is specifically: In the formula, Q * is the reactive power reference value, K is the reactive power adjustment coefficient, V FM is the fundamental positive sequence voltage, V N is the voltage rating of the wind turbine grid connection point, S new It is the allowable apparent power of wind turbines in the power grid.

4. The voltage coordination control method of a grid-type wind farm according to claim 1, characterized in that: The step of obtaining a corresponding phase angle based on the active power reference value and the active power output value is specifically as follows: Obtaining a first output value based on the active power reference value and the active power output value; Performing inertia simulation on the first output value to obtain an angular frequency adjustment amount; Based on the acquired rated angular frequency of the wind turbine generator set and the angular frequency adjustment amount, the actual angular frequency of the wind turbine generator set is obtained, and based on the actual angular frequency, the corresponding phase angle is obtained.

5. The voltage coordination control method of a grid-type wind farm according to claim 4, characterized in that: The calculation formula for obtaining the corresponding virtual inductance value based on the fundamental positive sequence voltage is specifically: Where, L v is the virtual inductance value, V FM is the fundamental positive sequence voltage, E is the internal potential voltage vector, ω is the actual angular frequency, I max is the AC current limit value of the wind turbine converter, L r is the actual inductance of the output filter, K is the reactive power adjustment coefficient, V N is the voltage rating of the wind turbine grid connection point, I N is the rated output current of the wind turbine.

6. The voltage coordination control method of a grid-type wind farm according to claim 1, characterized in that: Before obtaining the corresponding q-axis voltage modulation amount and d-axis voltage modulation amount based on the virtual inductance, the method further includes: Obtaining a reactive power output value of the converter, and obtaining a corresponding voltage regulation amount based on the reactive power reference value, the reactive power output value and a preset droop coefficient, wherein the droop coefficient is determined according to the impedance of each unit in the wind farm to the grid connection point; The voltage amplitude of the converter grid-connected point is obtained, and based on the voltage adjustment amount and the voltage amplitude, a corresponding control voltage reference value is obtained.

7. The voltage coordination control method of a grid-type wind farm according to claim 6, characterized in that: The corresponding d-axis voltage modulation amount obtained based on the virtual inductance is specifically: Obtaining a corresponding output current q-axis component and an output current d-axis component based on the collected wind turbine grid-connected point current, and obtaining a corresponding d-axis voltage reference value based on the output current q-axis component, the virtual inductance value and the control voltage reference value; Acquire a d-axis voltage component of a converter grid-connected point, and obtain a corresponding d-axis current inner loop reference value based on the d-axis voltage reference value and the d-axis voltage component; Based on the d-axis current inner loop reference value and the output current d-axis component, obtaining a corresponding d-axis control voltage; Based on the d-axis voltage component, the d-axis control voltage and the q-axis cross-coupling amount, the corresponding d-axis voltage modulation amount is obtained.

8. The voltage coordination control method of a grid-type wind farm according to claim 1, characterized in that: The corresponding q-axis voltage modulation amount obtained based on the virtual inductance is specifically: Obtaining a corresponding output current q-axis component and an output current d-axis component based on the collected wind turbine grid-connected point current, and obtaining a corresponding q-axis voltage reference value based on the output current d-axis component and the virtual inductance value; Acquire a q-axis voltage component of a converter grid-connected point, and obtain a corresponding q-axis current inner loop reference value based on the q-axis voltage reference value and the q-axis voltage component; Based on the q-axis current inner loop reference value and the output current q-axis component, obtaining a corresponding q-axis control voltage; Based on the q-axis voltage component, the q-axis control voltage and the d-axis cross-coupling amount, the corresponding q-axis voltage modulation amount is obtained.

9. The voltage coordination control method of a grid-type wind farm according to claim 1, characterized in that: The three-phase voltage modulation amount is determined by DQ / ABC transformation, wherein the calculation formula of the DQ / ABC transformation is specifically: In the formula, is the three-phase voltage modulation, θ is the phase angle, M dg is the d-axis voltage modulation, M qg is the q-axis voltage modulation amount.

10. A voltage coordination control device for a grid-type wind farm, characterized in that: include: An acquisition module, a first calculation module, a second calculation module and a control module; The acquisition module is used to obtain the corresponding fundamental positive sequence voltage based on the collected wind turbine grid connection point voltage, and obtain the corresponding reactive power reference value and active power reference value based on the fundamental positive sequence voltage; The first calculation module is used to obtain the active power output value of the converter, and obtain the corresponding phase angle based on the active power reference value and the active power output value; The second calculation module is used to obtain a corresponding virtual inductance value based on the fundamental positive sequence voltage, and obtain a corresponding d-axis voltage modulation amount and a q-axis voltage modulation amount based on the virtual inductance value; The control module is used to determine the three-phase voltage modulation amount based on the d-axis voltage modulation amount, the q-axis voltage modulation amount and the phase angle, and control the output voltage of the converter based on the three-phase voltage modulation amount.

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