Control method and control device for a wind turbine generator system
By performing DC bus voltage deviation calculation and virtual impedance control in the wind turbine generator set, the grid stability and power coupling problems at the wind turbine generator set grid connection point are solved, and the stability and dynamic performance of the system are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING GOLDWIND SCI & CREATION WINDPOWER EQUIP CO LTD
- Filing Date
- 2021-08-20
- Publication Date
- 2026-07-24
Smart Images
Figure CN115912452B_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of wind power generation, and more specifically, to a control method and control device for a wind turbine generator set. Background Technology
[0002] Wind power technology is developing rapidly, and its penetration rate in power grid applications is gradually increasing. Controlling wind turbine generators requires considering various factors, including grid stability and the coupling of active and reactive power. Effective control of the grid connection point of wind turbine generators remains a significant challenge. Summary of the Invention
[0003] The purpose of this disclosure is to provide a control method and control device for wind turbine generator sets, which can improve the stability of the power grid and the coupling of active and reactive power by controlling the injection voltage at the grid connection point of the wind turbine generator set.
[0004] According to embodiments of this disclosure, a control method for a wind turbine generator set is provided. The control method includes: obtaining an active power deviation by performing proportional-integral-differential calculations on the deviation between the measured DC bus voltage value and the reference DC bus voltage value of the wind turbine generator set; determining a virtual angular frequency deviation based on the active power deviation; determining a virtual internal potential phase based on the virtual angular frequency deviation; obtaining d-axis virtual impedance output and q-axis virtual impedance output by inputting the grid-connected current in the dq coordinate system to a virtual impedance module; determining the d-axis component and q-axis component of the modulation voltage based on the virtual angular frequency deviation, the reactive power setpoint of the wind turbine generator set, the measured reactive power value, the rated voltage amplitude of the grid, and the d-axis and q-axis virtual impedance outputs; and controlling the injection voltage at the grid connection point of the wind turbine generator set according to the virtual internal potential phase and the d-axis and q-axis components of the modulation voltage.
[0005] According to another embodiment of this disclosure, a control device for a wind turbine generator set is provided. The control device includes: an active power deviation acquisition unit configured to acquire active power deviation by performing proportional-integral-differential calculations on the deviation between the measured DC bus voltage value and the reference DC bus voltage value of the wind turbine generator set; a virtual angular frequency deviation determination unit configured to determine a virtual angular frequency deviation based on the active power deviation; a virtual internal potential phase determination unit configured to determine a virtual internal potential phase based on the virtual angular frequency deviation; a virtual impedance processing unit configured to obtain d-axis virtual impedance output and q-axis virtual impedance output by inputting the grid-connected current in the dq coordinate system to a virtual impedance module; a modulation voltage acquisition unit configured to determine the d-axis component and q-axis component of the modulation voltage based on the virtual angular frequency deviation, the reactive power setpoint of the wind turbine generator set, the reactive power measurement value, the rated voltage amplitude of the grid, and the d-axis virtual impedance output and q-axis virtual impedance output; and a voltage control unit configured to control the injection voltage at the grid connection point of the wind turbine generator set according to the virtual internal potential phase and the d-axis and q-axis components of the modulation voltage.
[0006] According to embodiments of the present disclosure, a computer-readable storage medium storing a computer program is provided, which, when executed by a processor, implements the control method for a wind turbine generator as described above.
[0007] According to an embodiment of this disclosure, a computing device is provided, the computing device comprising: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, the control method for a wind turbine generator set as described above is implemented.
[0008] By employing the control method and control device, computer-readable storage medium, and computing device for wind turbine generator sets according to embodiments of this disclosure, one of the following technical effects can be achieved: Taking into account various factors such as grid stability and the coupling of active and reactive power, the injection voltage at the grid connection point of the wind turbine generator set is controlled during the dynamic change of the DC bus voltage, thereby improving grid stability and the coupling of active and reactive power. For example, the injection voltage at the grid connection point of the voltage source type wind turbine generator set can be stably and effectively controlled, appropriately increasing the damping of the entire system while appropriately reducing the coupling degree of active and reactive power. By performing proportional-integral-differential calculations on the deviation between the measured DC bus voltage value and the reference DC bus voltage value of the wind turbine generator set, the frequency adaptability, parameter robustness, and deviation suppression speed of the wind turbine generator set are improved. By introducing a simulated power system PSS stabilizer in the reactive voltage droop control, the power system stability of the wind turbine generator set is improved. Attached Figure Description
[0009] The above and other objects and features of this disclosure will become clearer from the following description taken in conjunction with the accompanying drawings.
[0010] Figure 1 This is a flowchart of a control method for a wind turbine generator set according to an embodiment of the present disclosure.
[0011] Figure 2 This is a schematic block diagram of a control method for a wind turbine generator set according to an embodiment of the present disclosure.
[0012] Figure 3 This is a schematic diagram of the structure of a simulated power system PSS stabilizer according to an embodiment of the present disclosure.
[0013] Figure 4 It is an equivalent topology diagram according to an embodiment of the present disclosure, which represents an equivalent topology diagram in a stationary abc coordinate system.
[0014] Figure 5 This is a block diagram of a control device for a wind turbine generator set according to an embodiment of the present disclosure.
[0015] Figure 6 This is a block diagram of a computing device according to embodiments of the present disclosure.
[0016] Throughout the accompanying drawings, it should be noted that the same reference numerals are used to denote the same or similar elements, features, and structures. Detailed Implementation
[0017] To facilitate understanding of the technical concept of this invention, the relevant terms, the relationship between system frequency and DC bus voltage, etc., are explained and described below.
[0018] The power angle refers to the difference between the output voltage phase angle of the wind turbine generator's converter and the grid voltage phase angle. If the converter's output voltage phase angle leads the grid voltage phase angle (power angle greater than 0), active power flows from the converter to the AC system. Conversely, if the converter's output voltage phase angle lags behind the grid voltage phase angle (power angle less than 0), active power flows from the AC system to the converter. Secondly, the power angle remains constant when the converter's output voltage frequency matches the system frequency. Finally, under steady-state conditions, if the converter's output voltage phase angle leads the grid voltage phase angle (power angle greater than 0), active power flows from the converter to the AC system.
[0019] Based on the above facts, the following pattern can be observed: as the system frequency increases, the power angle decreases, and the active power transmitted between the converter and the AC system decreases accordingly. Since the DC voltage deviation (feedback value minus setpoint value) is the feedback value minus the setpoint value, the converter actively increases the DC bus voltage to maintain a constant DC bus voltage. After the rotor motion equation is applied, its own output frequency increases. This frequency, after integration, further increases the phase angle of the converter's output voltage, ultimately increasing the power angle between the converter and the AC system. This restores the power angle to its original stable value, maintaining the active power transmitted between the converter and the AC system. Of course, the above process can also be understood intuitively from another perspective: in order to maintain synchronization with the grid voltage (i.e., consistent frequency), the converter needs to increase its own output angular frequency to keep the power angle constant. Since the angular frequency is obtained by passing the DC voltage deviation through a first-order low-pass filter, the phenomenon of DC bus voltage increase occurs. When the system frequency decreases, the power angle increases, and the active power transmitted between the converter and the AC system increases. In order to maintain synchronization with the AC system, the converter needs to reduce the output voltage frequency, so the DC bus voltage drops.
[0020] This disclosure proposes a control method and control device for wind turbine generator sets, which can dynamically control the injection voltage at the grid connection point of the wind turbine generator set based on the DC bus voltage in the control system of the wind turbine generator set. By controlling the injection voltage at the grid connection point of the wind turbine generator set, the stability of the power grid and the coupling of active power and reactive power can be improved.
[0021] The following description, in conjunction with the accompanying drawings, provides specific embodiments to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, upon understanding this disclosure, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent. For example, the order of operations described herein is merely illustrative and is not limited to those orders set forth herein, but may be altered as will become clear upon understanding this disclosure, except for operations that must occur in a specific order. Furthermore, for clarity and conciseness, descriptions of features known in the art may be omitted.
[0022] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein, which will become clear upon understanding the disclosure of this application.
[0023] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more.
[0024] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts should not be limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Thus, without departing from the teaching of the examples described herein, the first component, first assembly, first region, first layer, or first part referred to as the first component, first assembly, first region, first layer, or first part may also be referred to as the second component, second assembly, second region, second layer, or second part.
[0025] The terminology used herein is for the purpose of describing various examples only and is not intended to limit disclosure. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. The terms “comprising,” “including,” and “having” indicate the presence of the described features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.
[0026] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains upon understanding this disclosure. Unless expressly defined herein, terms (such as those defined in a general dictionary) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this disclosure, and shall not be interpreted in an idealized or overly formalistic manner.
[0027] Furthermore, in the description of the examples, detailed descriptions of well-known related structures or functions will be omitted when it is believed that such detailed descriptions would lead to a vague interpretation of this disclosure.
[0028] Figure 1 This is a flowchart of a control method for a wind turbine generator set according to an embodiment of the present disclosure. Figure 2 This is a schematic block diagram of a control method for a wind turbine generator set according to an embodiment of the present disclosure.
[0029] like Figure 1 As shown, in step S101, the active power deviation is obtained by performing proportional-integral-differential calculations on the deviation between the measured DC bus voltage of the wind turbine generator set and the reference DC bus voltage.
[0030] According to embodiments of this disclosure, the deviation between the measured DC bus voltage of the wind turbine generator set and the reference DC bus voltage can be the difference or squared difference between the measured DC bus voltage and the reference DC bus voltage, but this disclosure is not limited to this and can also be other forms of deviation.
[0031] exist Figure 2In the illustrated embodiment, the DC bus voltage measurement value u is used. dc DC bus voltage reference value u dref The squared difference (i.e., u) dc 2 -u dref 2 This will be used as an example for illustration, but this disclosure is not limited to this.
[0032] like Figure 2 As shown, the measured value of DC bus voltage u dc DC bus voltage reference value u dref The squared difference is used to perform proportional-integral-derivative (PID) calculations to obtain the active power deviation ΔP. ref .
[0033] In the DC bus voltage control loop (also known as the self-synchronizing loop), the squared difference between the measured DC bus voltage value (also known as the DC bus voltage feedback value) and the reference DC bus voltage value is used as the input of the PID controller to perform PID calculations.
[0034] In the integration operation (K) i / s, where K i The integral gain (representing the integral gain) is used to integrate the deviation between the measured DC bus voltage and the reference DC bus voltage to address frequency adaptability issues. When the power grid deviates from its rated frequency (e.g., 50Hz), according to the relationship between system frequency and DC bus voltage described above, the actual DC bus voltage will deviate from the reference DC bus value. By integrating the deviation between the measured and reference DC bus voltage, a DC current can be introduced into the angular frequency deviation Δω to compensate for the error caused by the rated angular frequency ω0 of the power grid. It can be seen that the integral element plays a crucial role.
[0035] In the differential operation stage (sK) c , where K c The differential gain (represented by the differential calculation) is used to differentiate the deviation between the measured DC bus voltage and the reference DC bus voltage value to address the problem of poor parameter robustness. The energy stored in the DC bus capacitor (e.g., 0.5CU) 2Where C represents the DC bus capacitance and U represents the voltage across the DC bus capacitor, this reflects the cumulative effect of the active power deviation between the machine side and the grid side. If the energy stored in the DC bus capacitor is differentiated, the resulting differential value directly reflects the active power deviation between the machine side and the grid side. Analogous to a synchronous machine, if the machine-side active power is considered as mechanical power and the grid-side active power as electromagnetic power, then applying the active power deviation between the grid side and the machine side to the rotor with damping windings is equivalent to this active power deviation passing through a first-order low-pass filter 1 / (sK). J +K D ), where K J K represents the virtual inertia coefficient. D This represents the virtual damping coefficient. It can be seen that the differential element not only has a clear physical meaning, but its role is also very important.
[0036] In the proportional calculation stage (K) T , where K T The proportional gain is used to perform proportional calculations on the deviation between the measured DC bus voltage and the reference DC bus voltage in order to accelerate the response time of the dynamic process. In the initial stage of frequency change, it plays a role in quickly suppressing changes, making up for the slow response speed of the integral calculation stage, and also plays an auxiliary role in the differential calculation stage.
[0037] In step S102, the virtual angular frequency deviation is determined based on the active power deviation. For example, referring to... Figure 2 The active power deviation ΔP can be calculated. ref The input is fed into a first-order low-pass filter to obtain the output of the first-order low-pass filter, which is used as the virtual angular frequency deviation Δω. For example, but not limited to, it can be based on the function 1 / (sK) J +K D Construct a first-order low-pass filter to handle the active power deviation ΔP. ref This leads to the generation of a virtual angular frequency deviation Δω.
[0038] This disclosure is not limited to Figure 2 The illustrated embodiment. For example, the sum of the active power deviation and the active power on the machine side can be input to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation. Optionally, the difference between the active power deviation and the active power on the grid side can be input to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation. In this way, the overall control speed can be improved and the overall dynamic performance can be enhanced through feedforward control.
[0039] In step S103, the virtual internal potential phase is determined based on the virtual angular frequency deviation. For example, referring to... Figure 2The virtual angular frequency ω can be determined based on the virtual angular frequency deviation Δω and the rated angular frequency ω0 of the power grid; and the virtual internal potential phase θ can be determined based on the virtual angular frequency. Figure 2 In the illustrated embodiment, the virtual angular frequency deviation Δω and the rated angular frequency ω0 of the power grid are added to obtain the virtual angular frequency ω. Then, the virtual internal potential phase θ is obtained by integrating the virtual angular frequency ω.
[0040] In step S104, the grid-connected current in the dq coordinate system is input to the virtual impedance module to obtain the d-axis virtual impedance output and the q-axis virtual impedance output.
[0041] Reference Figure 2 In an exemplary embodiment of this disclosure, the virtual impedance can be expressed as R v +jX v , where R v and X v These represent virtual resistance and virtual reactance, respectively. The grid-connected current in the dq coordinate system is input to the virtual impedance module, which allows the grid-connected current i in the dq coordinate system to be controlled. gdq Multiplying the virtual impedance by the d-axis yields the d-axis and q-axis virtual impedance outputs. Applying virtual impedance can improve the damping of the entire control system and effectively reduce grid strength. Increasing the virtual impedance may increase the coupling between active and reactive power; that is, when active power changes, reactive power will also change, and vice versa. Therefore, the virtual impedance needs to be appropriately set and adjusted.
[0042] In step S105, based on the virtual angular frequency deviation, the reactive power setpoint of the wind turbine generator set, the reactive power measurement value, the rated voltage amplitude of the power grid, and the d-axis virtual impedance output and q-axis virtual impedance output, the d-axis component and q-axis component of the modulation voltage are determined.
[0043] According to an exemplary embodiment of this disclosure, firstly, a first disturbance of the AC bus voltage can be determined based on the virtual angular frequency deviation, and a second disturbance of the AC bus voltage can be determined by multiplying the deviation between the reactive power setpoint and the reactive power measurement value by a reactive power droop coefficient. Then, based on the first disturbance of the AC bus voltage, the second disturbance of the AC bus voltage, the rated voltage amplitude of the grid, and the d-axis virtual impedance output, the d-axis component of the grid-connected reference voltage in the dq coordinate system can be determined, and the q-axis component of the grid-connected reference voltage in the dq coordinate system can be determined based on the q-axis virtual impedance output. Finally, based on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system, the d-axis and q-axis components of the modulation voltage can be determined.
[0044] Reference Figure 2The first disturbance of the AC bus voltage can be determined by performing at least one of the following processes on the virtual angular frequency deviation: reset processing, amplification processing, and phase compensation processing. Specifically, the control loop of the simulated power system PSS stabilizer can be introduced to determine the first disturbance of the AC bus voltage, thereby solving the low-frequency oscillation problem.
[0045] Specifically, a PSS stabilizer used in a power system generally consists of an amplification stage, a reset stage, a phase compensation (correction) stage, and a limiting stage. Its output is superimposed on the voltage reference value as an excitation signal, such as... Figure 3 As shown. Figure 3 This is a schematic diagram of the structure of a simulated power system PSS stabilizer according to an embodiment of the present disclosure.
[0046] Reference Figure 3 K represents the amplification stage of the PSS stabilizer. This indicates the reset circuit of the PSS stabilizer. This represents the phase compensation stage of the PSS stabilizer, while max-min represents the limiting stage. The parameters in each stage can be set differently according to the actual situation.
[0047] According to embodiments of this disclosure, the reset circuit makes the PSS stabilizer output zero when t→∞ (s→0), thus filtering out the DC component in Δω. Simultaneously, during the transition process, the reset circuit allows the dynamic signal to pass smoothly, ensuring the PSS stabilizer only functions during dynamic processes. The phase compensation circuit can consist of 1 to 3 lead compensation circuits, with each lead circuit capable of correcting up to 30° to 40°. Therefore, the lead circuit can compensate for (cancele) phase lag. The amplification factor K of the amplification circuit ensures sufficient voltage amplitude. Therefore, by introducing a PSS stabilizer into the reactive voltage droop control loop 2, the system stability can be improved.
[0048] Return to reference Figure 1 ,exist Figure 1 In this context, the PSS stabilizer may include a high-pass filter. Phase compensator The amplifier K is used, where the high-pass filter serves as the reset stage of the PSS stabilizer, filtering out the DC component in Δω. The phase compensator serves as the lead compensation stage of the PSS stabilizer, improving the phase margin at oscillation risk points. The amplifier serves as the proportional stage of the PSS stabilizer, enhancing the positive damping effect.
[0049] Although Figure 1 and Figure 3 The PSS stabilizer shown includes a reset stage, a phase compensation stage, and an amplification stage; however, the PSS stabilizer of this disclosure may include at least one of the reset stage, phase compensation stage, and amplification stage.
[0050] The first disturbance to the AC bus voltage can be determined by performing at least one of the following processes: reset processing, amplification processing, and phase compensation processing on the virtual angular frequency deviation. For example, referring to... Figure 1 The first disturbance ΔU1 is obtained by performing reset, amplification, and phase compensation processing on the virtual angular frequency deviation Δω. Here, when calculating the first disturbance ΔU1, the following methods can be used: Figure 2 The virtual angular frequency deviation is processed in the order shown, including amplification, reset, and phase compensation, or another order, to obtain the first disturbance ΔU1.
[0051] In addition, refer to Figure 2 The deviation between the reactive power setpoint Q0 and the reactive power measured value Q can be multiplied by the reactive power droop coefficient K. Q The second disturbance ΔU2 of the AC bus voltage is obtained. Then, the rated voltage amplitude U0 of the grid, the first disturbance ΔU1 of the AC bus voltage, and the second disturbance ΔU1 of the AC bus voltage are added together, and then the d-axis virtual impedance output is subtracted to obtain the d-axis component U of the grid-connected reference voltage in the dq coordinate system. dv * The q-axis voltage setting value U at the grid connection point can be set. q * Subtracting the q-axis virtual impedance from the output yields the q-axis component U of the grid-connected reference voltage in the dq coordinate system. qv * In embodiments of this disclosure, the grid connection point q-axis voltage setpoint U can be... q * Set to 0 to make the dq coordinate system oriented based on grid voltage.
[0052] According to exemplary embodiments of this disclosure, the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system can be controlled only by the outer voltage loop, or by both the outer voltage loop and the inner current loop, to obtain the d-axis and q-axis components of the modulated voltage.
[0053] For example, refer to Figure 2 The d-axis component U of the grid-connected reference voltage in the dq coordinate system can be expressed. dv * and q-axis component U qv * The input is sent to the voltage outer loop control module 201. Simultaneously, the grid-connected voltage u in the dq coordinate system can also be... dq and the grid-connected current i in the dq coordinate system gdq The input is sent to the voltage outer loop control module 201. The voltage outer loop control module 201 can control the d-axis component U of the grid-connected reference voltage in the dq coordinate system. dv * and q-axis component U qv* Perform voltage outer loop control to obtain the d-axis filter inductor current reference value i. d * and q-axis filter inductor current reference value i q * The reference value i of the d-axis filter inductor current can be used. d * and q-axis filter inductor current reference value i q * The input is sent to the current inner loop control module 202. Simultaneously, the grid-connected voltage u in the dq coordinate system can also be... dq and the filter inductor current i in the dq coordinate system dq The input is sent to the current inner loop control module 202. The current inner loop control module 202 can control the d-axis filter inductor current reference value i. d * and q-axis filter inductor current reference value i q * Perform inner-loop current control to obtain the d-axis component u of the modulation voltage. md and q-axis component u mq .
[0054] In embodiments of this disclosure, a current limiting module can be added between the voltage outer loop control module 201 and the current inner loop control module 202 to limit the current output by the voltage outer loop control module 201.
[0055] In addition, through the Figure 2 With appropriate modifications, the voltage outer loop control module 201 shown can perform voltage outer loop control only on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system without performing current inner loop control, so as to obtain the d-axis and q-axis components of the modulated voltage.
[0056] Referring back to 1, in step S106, the injection voltage at the grid connection point of the wind turbine generator is controlled according to the virtual internal potential phase and the d-axis and q-axis components of the modulation voltage.
[0057] According to embodiments of this disclosure, the d-axis and q-axis components of the modulated voltage can be converted into a three-phase voltage in the abc coordinate system based on the virtual internal potential phase in the dq coordinate system. For example, referring to... Figure 2 The d-axis component u of the modulated voltage can be converted using the dq / abc conversion module 203 based on the virtual internal potential phase θ in the dq coordinate system. md and q-axis component u mqThe voltage is converted to a three-phase voltage in the abc coordinate system and then input to the SVPWM (Space Vector Pulse Width Modulation) module 204 for space vector pulse width modulation. The three-phase voltage after space vector pulse width modulation can be input to the converter 205, which is then used to control the injection voltage at the grid connection point of the wind turbine generator.
[0058] As described above, based on variables such as DC bus voltage and grid-connected current in the dq coordinate system, a PID controller and a virtual impedance module can be used to obtain the modulation voltage and virtual internal potential phase in the dq coordinate system, which can then be used to control the injection voltage at the grid connection point of the wind turbine generator set. Through the control method for the wind turbine generator set according to the embodiments of this disclosure, stable and effective control of the injection voltage at the grid connection point of the voltage source type wind turbine generator set can be achieved, appropriately increasing the damping of the entire system while appropriately reducing the coupling degree between active and reactive power. Furthermore, by using a PID controller to adjust the DC bus voltage deviation, the problems of poor frequency adaptability and parameter robustness of the wind turbine generator set can be solved, and by introducing a PSS stabilizer, the system stability of the wind turbine generator set can be improved.
[0059] In the embodiments of this disclosure, the wind turbine generator set may be a voltage source type wind turbine generator set, but this disclosure is not limited thereto.
[0060] exist Figure 2 In the control system shown, a virtual impedance module is added to the input of the voltage outer loop control. After voltage outer loop and current inner loop control, the converter achieves the following control effect in steady state: the dq-axis component of the grid-connected voltage is equal to the dq voltage reference value of the control system. Due to the mathematical mapping relationship between the stationary abc coordinate system and the rotating dq coordinate system, the virtual impedance added to the dq-axis voltage reference value of the control system is equivalent to having a virtual impedance connected in series at the converter grid-connected point, such as... Figure 4 As shown.
[0061] Figure 4 It is an equivalent topology diagram according to an embodiment of the present disclosure, which represents an equivalent topology diagram in a stationary abc coordinate system.
[0062] Reference Figure 4 u dc (t) represents the DC bus voltage that varies with time t, i a i b and i c Indicates the current filtering inductance L f The three-phase current.
[0063] Before adding the virtual impedance, the filter capacitor C is controlled. f The three-phase voltage u au b and u c After implementing the aforementioned strategy, a virtual impedance (R0) is introduced into the main circuit. v +jL v Meanwhile, the voltage control point is no longer the filter capacitor voltage, but the three-phase voltage (u') at the grid connection point. a ,u' b ,u' c ), which can also be represented as E∠δ. As can be seen from the figure, (u' a ,u' b ,u' c ) and system power u s A negative virtual impedance (-R) is added between them. v -jL v The negative virtual resistance -R v and virtual sensory resistance-L v It can offset the resistance R of the transmission line. ∑ and resistance L ∑ This further decouples active power from reactive power.
[0064] However, if the negative virtual resistance -R v and virtual sensory resistance-L v An improperly chosen value can cause negative damping in the entire system, leading to a risk of oscillation. Therefore, to improve system damping, a positive virtual resistance +R needs to be introduced. v and virtual sensory resistance +L v Without increasing the coupling between active and reactive power, the positive damping of the system can be appropriately increased. This is to ensure that the system's positive damping is within the range of E∠δ and the system power supply u. s Introduce a positive virtual resistance +R between them v and virtual sensory resistance +L v , (u' a ,u' b ,u' c The signs of the virtual resistance and virtual reactance on the left and right sides can be reversed, thus introducing a negative virtual impedance (-R) into the main circuit. v -jL v ).
[0065] As mentioned above, the stability of the control system can be improved by introducing a positive virtual impedance into the main circuit. Furthermore, when the stability of the control system is sufficient but the transmission line impedance is too high, a negative virtual impedance can be introduced into the main circuit. In this way, the dynamic performance of the system can be improved by introducing virtual impedance.
[0066] Figure 5This is a block diagram of a control device for a wind turbine generator set according to an embodiment of the present disclosure. The control device 500 for the wind turbine generator set according to an embodiment of the present disclosure can be located in the central controller of a wind farm, in the main control unit of the wind turbine generator set, or in any other computing device communicating with the wind turbine generator set. In embodiments of the present disclosure, the wind turbine generator set can be a voltage source type wind turbine generator set.
[0067] The control device 500 may include an active power deviation acquisition unit 501, a virtual angular frequency deviation determination unit 502, a virtual internal potential phase determination unit 503, a virtual impedance processing unit 504, a modulation voltage acquisition unit 505, and a voltage control unit 506.
[0068] The active power deviation acquisition unit 501 is configured to acquire the active power deviation by performing proportional-integral-differential calculations on the deviation between the measured DC bus voltage of the wind turbine generator set and the reference DC bus voltage. Here, the deviation between the measured DC bus voltage and the reference DC bus voltage can be the difference between the measured DC bus voltage and the reference DC bus voltage, or the difference of the squares of the two values.
[0069] The virtual angular frequency deviation determination unit 502 is configured to determine the virtual angular frequency deviation based on the active power deviation. According to embodiments of this disclosure, the virtual angular frequency deviation determination unit 502 can directly input the active power deviation to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation. Alternatively, the virtual angular frequency deviation determination unit 502 can input the sum of the active power deviation and the active power on the machine side to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation; or it can input the difference between the active power deviation and the active power on the grid side to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation.
[0070] The virtual internal potential phase determination unit 503 is configured to determine the virtual internal potential phase based on the virtual angular frequency deviation. According to embodiments of this disclosure, the virtual internal potential phase determination unit 503 can determine the virtual angular frequency based on the virtual angular frequency deviation and the rated angular frequency of the power grid, and determine the virtual internal potential phase based on the virtual angular frequency.
[0071] The virtual impedance processing unit 504 is configured to obtain d-axis virtual impedance output and q-axis virtual impedance output by inputting the grid-connected current in the dq coordinate system to the virtual impedance module.
[0072] The modulation voltage acquisition unit 505 is configured to determine the d-axis and q-axis components of the modulation voltage based on the virtual angular frequency deviation, the reactive power setpoint of the wind turbine generator, the reactive power measurement value, the rated voltage amplitude of the power grid, and the d-axis virtual impedance output and q-axis virtual impedance output. According to embodiments of this disclosure, the modulation voltage acquisition unit 505 can first determine a first disturbance of the AC bus voltage based on the virtual angular frequency deviation, and then determine a second disturbance of the AC bus voltage by multiplying the deviation between the reactive power setpoint and the reactive power measurement value by a reactive power droop coefficient. Subsequently, the modulation voltage acquisition unit 505 can determine the d-axis component of the grid-connected reference voltage in the dq coordinate system based on the first disturbance of the AC bus voltage, the second disturbance of the AC bus voltage, the rated voltage amplitude of the power grid, and the d-axis virtual impedance output, and determine the q-axis component of the grid-connected reference voltage in the dq coordinate system based on the q-axis virtual impedance output. Finally, the modulation voltage acquisition unit 505 can determine the d-axis and q-axis components of the modulation voltage based on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system.
[0073] Here, the modulation voltage acquisition unit 505 can perform voltage outer loop control on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system to obtain the d-axis and q-axis components of the modulation voltage; the modulation voltage acquisition unit 505 can perform voltage outer loop control on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system to obtain the d-axis and q-axis components of the modulation voltage; or, the modulation voltage acquisition unit 505 can determine the first disturbance amount of the AC bus voltage by performing at least one of the following: reset processing, amplification processing, and phase compensation processing on the virtual angular frequency deviation.
[0074] The voltage control unit 506 is configured to control the injection voltage at the grid connection point of the wind turbine generator based on the phase of the virtual internal potential and the d-axis and q-axis components of the modulated voltage.
[0075] For reference Figures 1 to 4 The operation of each unit in the control device 5 is explained based on the control method of the wind turbine generator set disclosed herein, and will not be elaborated further here for the sake of brevity.
[0076] According to embodiments of this disclosure, a computer-readable storage medium storing instructions may also be provided, wherein when the instructions are executed by at least one processor, they cause at least one processor to perform a control method for a wind turbine generator according to this disclosure. Examples of computer-readable storage media herein include: read-only memory (ROM), random access programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, non-volatile memory, CD-ROM, CD-R, CD+R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, Blu-ray or optical disc storage, hard disk drive (HDD), solid-state drive (SSD), card storage (such as multimedia cards, secure digital (SD) cards, or ultra-fast digital (XD) cards), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, and any other device configured to store a computer program and any associated data, data files, and data structures in a non-transitory manner and to provide the computer program and any associated data, data files, and data structures to a processor or computer so that the processor or computer can execute the computer program. The computer program in the aforementioned computer-readable storage medium can run in an environment deployed in computer devices such as clients, hosts, agent devices, servers, etc. Furthermore, in one example, the computer program and any associated data, data files, and data structures are distributed across a networked computer system, such that the computer program and any associated data, data files, and data structures are stored, accessed, and executed in a distributed manner through one or more processors or computers.
[0077] Figure 6 This is a block diagram of a computing device according to embodiments of the present disclosure.
[0078] Reference Figure 6 The computing device 600 according to an embodiment of the present disclosure may include a memory 601 and a processor 602. A computer program is stored in the memory 601. When the computer program is executed by the processor 602, it implements the control method of the wind turbine generator set according to an embodiment of the present disclosure.
[0079] In embodiments of this disclosure, when the computer program is executed by processor 602, reference can be implemented. Figures 1 to 4The described operation of the wind turbine generator control method is as follows: Active power deviation is obtained by performing proportional-integral-differential (PID) calculations on the deviation between the measured DC bus voltage and the reference DC bus voltage of the wind turbine generator; based on the active power deviation, the virtual angular frequency deviation is determined; based on the virtual angular frequency deviation, the virtual internal potential phase is determined; by inputting the grid-connected current in the dq coordinate system to the virtual impedance module, d-axis virtual impedance output and q-axis virtual impedance output are obtained; based on the virtual angular frequency deviation, the reactive power setpoint of the wind turbine generator, the measured reactive power, the rated voltage amplitude of the grid, and the d-axis and q-axis virtual impedance outputs, the d-axis and q-axis components of the modulation voltage are determined; according to the virtual internal potential phase and the d-axis and q-axis components of the modulation voltage, the injection voltage at the grid connection point of the wind turbine generator is controlled.
[0080] Figure 6 The computing device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments disclosed herein.
[0081] The above has been referred to Figures 1 to 6 A control method, control device, computer-readable storage medium, and computing device for a wind turbine generator set according to embodiments of the present disclosure are described. However, it should be understood that: Figure 5 The control device and its individual units shown can be configured to perform specific functions as software, hardware, firmware, or any combination thereof. Figure 6 The computing device shown is not limited to the components shown above, but some components may be added or removed as needed, and the above components may also be combined.
[0082] By employing the control method and control device for wind turbine generator sets according to embodiments of this disclosure, at least one of the following technical effects can be achieved: Taking into account various factors such as grid stability and the coupling of active and reactive power, the injection voltage at the grid connection point of the wind turbine generator set is controlled during the dynamic change of the DC bus voltage, thereby improving grid stability and the coupling of active and reactive power. For example, the injection voltage at the grid connection point of the voltage source type wind turbine generator set can be stably and effectively controlled, appropriately increasing the damping of the entire system while appropriately reducing the coupling degree of active and reactive power. By performing proportional-integral-differential calculations on the deviation between the measured DC bus voltage value and the reference DC bus voltage value of the wind turbine generator set, the frequency adaptability, parameter robustness, and deviation suppression speed of the wind turbine generator set are improved. By introducing a simulated power system PSS stabilizer in the reactive voltage droop control, the power system stability of the wind turbine generator set is improved.
[0083] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.
[0084] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.
Claims
1. A control method for a wind turbine generator set, characterized in that, The control method includes: The active power deviation is obtained by performing proportional-integral-differential calculations on the deviation between the measured DC bus voltage of the wind turbine generator set and the reference DC bus voltage. The virtual angular frequency deviation is determined based on the active power deviation. The virtual internal potential phase is determined based on the virtual angular frequency deviation; By inputting the grid-connected current in the dq coordinate system to the virtual impedance module, the d-axis virtual impedance output and the q-axis virtual impedance output are obtained; Based on the virtual angular frequency deviation, the reactive power setpoint of the wind turbine generator set, the reactive power measurement value, the rated voltage amplitude of the power grid, and the d-axis virtual impedance output and q-axis virtual impedance output, the d-axis component and q-axis component of the modulation voltage are determined. The injection voltage at the grid connection point of the wind turbine generator is controlled based on the phase of the virtual internal potential and the d-axis and q-axis components of the modulation voltage.
2. The control method according to claim 1, characterized in that, The step of determining the d-axis and q-axis components of the modulation voltage includes: The first disturbance of AC bus voltage is determined based on virtual angular frequency deviation; The second disturbance of AC bus voltage is determined by multiplying the deviation between the reactive power setpoint and the reactive power measurement value by the reactive power droop coefficient. Based on the first disturbance of AC bus voltage, the second disturbance of AC bus voltage, the rated voltage amplitude of the grid, and the d-axis virtual impedance output, the d-axis component of the grid-connected reference voltage in the dq coordinate system is determined. Based on the q-axis virtual impedance output, determine the q-axis component of the grid-connected reference voltage in the dq coordinate system; Based on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system, determine the d-axis and q-axis components of the modulation voltage.
3. The control method according to claim 2, characterized in that, The step of determining the d-axis and q-axis components of the modulation voltage based on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system includes: The d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system are controlled by either the outer voltage loop or by a combination of outer voltage loop control and inner current loop control to obtain the d-axis and q-axis components of the modulated voltage.
4. The control method according to claim 2, characterized in that, The step of determining the first disturbance of the AC bus voltage based on the virtual angular frequency deviation includes: The first disturbance of the AC bus voltage is determined by performing at least one of the following processes on the virtual angular frequency deviation: reset processing, amplification processing, and phase compensation processing.
5. The control method according to claim 1, characterized in that, The step of determining the virtual angular frequency deviation based on the active power deviation includes: The active power deviation is directly input to a first-order low-pass filter to obtain the output of the first-order low-pass filter, which is used as the virtual angular frequency deviation; or The sum of the active power deviation and the active power on the machine side is input to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation; or The difference between the active power deviation and the grid-side active power is input to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation.
6. The control method according to claim 1, characterized in that, The step of determining the virtual internal potential phase based on the virtual angular frequency deviation includes: The virtual angular frequency is determined based on the virtual angular frequency deviation and the rated angular frequency of the power grid; The phase of the virtual internal potential is determined based on the virtual angular frequency.
7. The control method according to claim 1, characterized in that, The wind turbine generator set is a voltage source type wind turbine generator set.
8. A control device for a wind turbine generator set, characterized in that, The control device includes: The active power deviation acquisition unit is configured to acquire the active power deviation by performing proportional-integral-differential calculations on the deviation between the measured value of the DC bus voltage of the wind turbine generator set and the reference value of the DC bus voltage. The virtual angular frequency deviation determination unit is configured to determine the virtual angular frequency deviation based on the active power deviation; The virtual internal potential phase determination unit is configured to determine the virtual internal potential phase based on the virtual angular frequency deviation; The virtual impedance processing unit is configured to obtain d-axis virtual impedance output and q-axis virtual impedance output by inputting the grid-connected current in the dq coordinate system to the virtual impedance module. The modulation voltage acquisition unit is configured to determine the d-axis and q-axis components of the modulation voltage based on the virtual angular frequency deviation, the reactive power setpoint of the wind turbine generator set, the reactive power measurement value, the rated voltage amplitude of the power grid, and the d-axis virtual impedance output and q-axis virtual impedance output. The voltage control unit is configured to control the injection voltage at the grid connection point of the wind turbine generator based on the phase of the virtual internal potential and the d-axis and q-axis components of the modulated voltage.
9. The control device according to claim 8, characterized in that, The modulation voltage acquisition unit is configured to: The first disturbance of AC bus voltage is determined based on virtual angular frequency deviation; The second disturbance of AC bus voltage is determined by multiplying the deviation between the reactive power setpoint and the reactive power measurement value by the reactive power droop coefficient. Based on the first disturbance of AC bus voltage, the second disturbance of AC bus voltage, the rated voltage amplitude of the grid, and the d-axis virtual impedance output, the d-axis component of the grid-connected reference voltage in the dq coordinate system is determined. Based on the q-axis virtual impedance output, determine the q-axis component of the grid-connected reference voltage in the dq coordinate system; Based on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system, determine the d-axis and q-axis components of the modulation voltage.
10. The control device according to claim 9, characterized in that, The modulation voltage acquisition unit is further configured to: The outer voltage loop control is performed on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system to obtain the d-axis and q-axis components of the modulated voltage; or the outer voltage loop control and inner current loop control are performed on the d-axis and q-axis components of the grid-connected reference voltage in the dq coordinate system to obtain the d-axis and q-axis components of the modulated voltage. The first disturbance of the AC bus voltage is determined by performing at least one of the following processes on the virtual angular frequency deviation: reset processing, amplification processing, and phase compensation processing.
11. The control device according to claim 8, characterized in that, The virtual angular frequency deviation determination unit is configured as follows: The active power deviation is directly input to a first-order low-pass filter to obtain the output of the first-order low-pass filter as a virtual angular frequency deviation. or The sum of the active power deviation and the active power on the machine side is input to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation. or The difference between the active power deviation and the grid-side active power is input to a first-order low-pass filter to obtain the output of the first-order low-pass filter as the virtual angular frequency deviation.
12. The control device according to claim 8, characterized in that, The virtual internal potential phase determination unit is configured as follows: The virtual angular frequency is determined based on the virtual angular frequency deviation and the rated angular frequency of the power grid; The phase of the virtual internal potential is determined based on the virtual angular frequency.
13. The control device according to claim 8, characterized in that, The wind turbine generator set is a voltage source type wind turbine generator set.
14. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the control method for the wind turbine generator set as described in any one of claims 1 to 7.
15. A computing device, characterized in that, The computing device includes: processor; A memory that stores a computer program, which, when executed by a processor, implements the control method for a wind turbine generator as described in any one of claims 1 to 7.