Converter control method and control device for voltage source wind turbine generator

Abstract

The present disclosure provides a converter control method and control device for a voltage source wind turbine generator. The converter control method comprises: determining a reactive current given value and an active current given value of a generator-side converter; determining a direct-current voltage damping output value on the basis of the active current given value; determining a modulation voltage reference value of the generator-side converter on the basis of the reactive current given value, the active current given value, and an input current of the generator-side converter; and controlling operation of the generator-side converter on the basis of the modulation voltage reference value of the generator-side converter.

Description

Converter control method and control device for voltage source type wind turbine generator set Technical Field

[0001] The present disclosure relates to the field of wind power generation, and more particularly to a converter control method and a control device for a voltage source type wind turbine generator set. Background Art

[0002] Wind turbines are devices that convert wind energy into electrical energy. In voltage-source wind turbines, the generator-side converter converts the AC power output of the wind turbine into DC power, controlling the DC bus voltage. The grid-side converter uses virtual synchronous generation control technology to convert DC power into AC power. However, existing technologies typically employ independent control of the generator-side and grid-side converters, failing to consider the differences in control performance between the generator-side and grid-side converters during operation.

[0003] Summary of the Invention

[0004] The purpose of the embodiments of the present disclosure is to provide a converter control method and control device for a voltage source wind turbine generator set, which can avoid low-frequency oscillation of the converter DC bus voltage, effectively improve the stability of converter control, and reduce the usage rate of the converter braking resistor.

[0005] In a general aspect, a converter control method for a voltage source type wind turbine generator set is provided, the control method comprising: determining a reactive current set value and an active current set value of the machine-side converter based on a weak magnetic voltage set value, an input voltage of the machine-side converter, and a measured value of the converter's DC bus voltage and a set DC bus voltage; determining a DC voltage damping output value based on the active current set value, wherein the DC voltage damping output value is used to determine an active power reference value of the grid-side converter of the wind turbine generator set; determining a modulation voltage reference value of the machine-side converter based on the reactive current set value, the active current set value, and the input current of the machine-side converter; and controlling the operation of the machine-side converter according to the modulation voltage reference value of the machine-side converter.

[0006] In another general aspect, a converter control device for a voltage source wind turbine generator set is provided, the control device comprising: a current set value determination unit, configured to determine a reactive current set value and an active current set value of the machine-side converter based on a weak magnetic voltage set value, an input voltage of the machine-side converter, and a measured value of the DC bus voltage of the converter and a DC bus voltage set value; a damping determination unit, configured to determine a DC voltage damping output value based on the active current set value, wherein the DC voltage damping output value is used to determine an active power reference value of the grid-side converter of the wind turbine generator set; a first voltage reference value determination unit, configured to determine a modulation voltage reference value of the machine-side converter based on the reactive current set value, the active current set value and the input current of the machine-side converter; and a first control unit, configured to control the operation of the machine-side converter according to the modulation voltage reference value of the machine-side converter.

[0007] In another general aspect, a computing device is provided, comprising: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, the converter control method of the voltage source wind turbine generator set as described above is implemented.

[0008] In another general aspect, a voltage source type wind turbine generator set is provided, wherein the voltage source type wind turbine generator set includes the converter control device as described above or the computing device as described above.

[0009] According to the converter control method and control device of the voltage source wind turbine generator set in the embodiment of the present disclosure, damping control is achieved by calculating the damping output value in the machine-side control strategy of the converter controller and applying the damping output value in the grid-side control strategy, thereby improving the control stability of the voltage source wind turbine generator set during high-power operation, avoiding the problem of low-frequency oscillation divergence of the converter DC bus voltage and generator torque, effectively reducing the risk of frequent starting of the converter braking resistor and converter fault shutdown, and reducing the power generation loss caused by faults of the wind turbine generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects and features of the present disclosure will become more apparent from the following description in conjunction with the accompanying drawings.

[0011] FIG1 is a schematic block diagram illustrating a converter control strategy for a wind turbine generator system.

[0012] 2A is a flowchart illustrating a converter control method for a voltage source wind turbine generator set according to an embodiment of the present disclosure, and FIG. 2B is a schematic block diagram illustrating a converter control method for a voltage source wind turbine generator set according to an embodiment of the present disclosure.

[0013] 3A is a flowchart illustrating a converter control method for a voltage source wind turbine generator set according to another embodiment of the present disclosure. FIG. 3B is a schematic block diagram illustrating a converter control method for a voltage source wind turbine generator set according to another embodiment of the present disclosure.

[0014] FIG4 is a block diagram illustrating a converter control device of a voltage source wind turbine generator system according to an embodiment of the present disclosure.

[0015] FIG5 is a block diagram illustrating a computing device according to an embodiment of the present disclosure.

[0016] FIG6 is a graph showing the DC bus voltage and generator torque value of a conventional voltage source wind turbine generator set without damping control when operating at high power.

[0017] FIG7 is a graph showing a DC bus voltage and a generator torque value of a voltage source wind turbine generator set according to an embodiment of the present disclosure when operating at high power. DETAILED DESCRIPTION

[0018] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices and / or systems described herein. However, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be clear after understanding the disclosure of the present application. For example, the order of operations described herein is merely an example and is not limited to those orders set forth herein, but can be changed as will be clear after understanding the disclosure of the present application, except for operations that must occur in a specific order. In addition, for greater clarity and conciseness, descriptions of features known in the art may be omitted.

[0019] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided to illustrate only some of the many possible ways to implement the methods, devices, and / or systems described herein, which will become clear after understanding the disclosure of this application.

[0020] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more.

[0021] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions should not be limited by these terms. Instead, these terms are used solely to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, what is referred to as a first member, first component, first region, first layer, or first portion in the examples described herein may also be referred to as a second member, second component, second region, second layer, or second portion without departing from the teachings of the examples.

[0022] In the specification, when an element (such as a layer, region, or substrate) is described as being “on,” “connected to,” or “coupled to” another element, the element may be directly “on,” “connected to,” or “coupled to” the other element, or one or more other elements may be present therebetween. Conversely, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, there may be no other elements present therebetween.

[0023] The terms used herein are intended only to describe various examples and are not intended to limit the disclosure. Unless the context clearly indicates otherwise, the singular is intended to include the plural. The terms "comprise," "include," and "have" indicate the presence of the recited 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.

[0024] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure pertains after understanding the present disclosure. Unless expressly defined otherwise herein, terms (such as those defined in general dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and should not be interpreted in an idealized or overly formal manner.

[0025] Furthermore, in describing the examples, when it is deemed that a detailed description of well-known related structures or functions would cause ambiguous interpretation of the present disclosure, such detailed description will be omitted.

[0026] The converter of a wind turbine generator set includes a machine-side converter and a grid-side converter. When the converter is operating at high power, the machine-side converter and the grid-side converter need to achieve DC bus voltage stability while performing power control. Therefore, in a grid-type unit (i.e., a voltage source wind turbine generator set), the control bandwidth required for the DC bus voltage control of the machine-side converter is typically tens of hertz to ensure that the voltage can be quickly and dynamically adjusted when the wind turbine transmits power to the grid. On the other hand, the grid-side converter uses virtual synchronous power generation control technology. The internal potential generated by this virtual synchronous power generation control technology (i.e., virtual internal potential) has slow dynamic characteristics, and the control bandwidth required is typically less than 5 hertz. As a result, the inconsistency of the machine-grid side control bandwidth leads to a large machine-grid side power difference in the DC capacitor, which in turn causes the DC bus voltage of the converter and the generator torque to experience continuous low-frequency oscillations. Low-frequency oscillations in the generator torque can adversely affect the wind turbine's drivetrain system, while low-frequency oscillations in the DC bus voltage can cause the converter's braking resistor to frequently activate, until the converter detects a fault and trips. Consequently, when the converter is operating at high power, the wind turbine will not be able to operate normally in a steady state, severely reducing the service life of the converter's braking resistor and increasing power loss.

[0027] On the other hand, when a wind turbine operates at high power, large wind speed fluctuations will cause large fluctuations in generator-side power. In this case, the generator-side converter must rapidly adjust the DC bus voltage to achieve rapid generator-side power control. Furthermore, the grid-side converter uses a virtual synchronous generator (VSG) control scheme with slow dynamic characteristics. The operating bandwidth of the reactive / voltage link and the synchronization link is small, making the response speed of grid-side power control slower than that of the generator-side power control. This deteriorates the electro-mechanical coupling of the wind turbine during high-power operation, and the converter's DC capacitors are prone to power imbalance, causing low-frequency oscillations in the generator torque and DC bus voltage. Excessive DC bus voltage oscillations can trigger the converter's braking resistors, while strong generator torque oscillations can reduce the stability of the wind turbine's drive train. Consequently, the wind turbine will shut down due to safety protection triggered by the low-frequency oscillation.

[0028] To this end, an embodiment of the present disclosure provides a converter control method and control device for a voltage source wind turbine generator set, which realizes damping control by calculating the damping output value in the machine-side control strategy of the converter controller and applying the damping output value in the grid-side control strategy, thereby improving the dynamic performance of the grid-side converter and the balance of the machine-grid side power, thereby avoiding low-frequency oscillation of the converter DC bus voltage, effectively improving the stability of the converter control, and reducing the utilization rate of the converter braking resistor.

[0029] FIG1 is a schematic block diagram illustrating a converter control strategy for a wind turbine generator system.

[0030] Referring to Figure 1 , the control system of a wind turbine generator set may include a main controller, a pitch controller, and a current conversion control system. The current conversion control system includes a machine-side converter controller and a grid-side converter controller. The machine-side converter controller and the grid-side converter controller may be integrated into a single controller or provided separately. Signals can be transmitted between the machine-side converter controller and the grid-side converter controller. During wind turbine control, the main controller can issue pitch angle commands to the pitch controller to adjust the mechanical torque of the rotor. Simultaneously, the main controller can issue control commands to the current conversion control system. The machine-side converter controller and the grid-side converter controller can control the operation of the machine-side converter and the grid-side converter, respectively, based on the control commands issued by the main controller. Furthermore, the machine-side converter controller can provide feedback to the main controller regarding the generator speed and electromagnetic torque of the wind turbine generator set. Based on the generator speed and electromagnetic torque, the main controller can issue torque / power reference commands to the grid-side converter controller. The grid-side converter controller can control the generator torque based on the torque and power reference commands and control the grid-connected power of the wind turbine generator set. Note that the converter of the wind turbine generator system shown in FIG1 is a three-level converter, but the present disclosure is not limited thereto.

[0031] Figure 2A is a flow chart showing a converter control method for a voltage source type wind turbine generator set according to an embodiment of the present disclosure, and Figure 2B is a schematic block diagram showing a converter control method for a voltage source type wind turbine generator set according to an embodiment of the present disclosure. Figure 3A is a flow chart showing a converter control method for a voltage source type wind turbine generator set according to another embodiment of the present disclosure, and Figure 3B is a schematic block diagram showing a converter control method for a voltage source type wind turbine generator set according to another embodiment of the present disclosure. The converter control method for a voltage source type wind turbine generator set according to an embodiment of the present disclosure is preferably executed by a converter controller of the wind turbine generator set (i.e., the converter control system shown in Figure 1, which includes a machine-side converter controller and a grid-side converter controller). However, the present disclosure is not limited thereto. The converter control method for a voltage source type wind turbine generator set may also be executed by a main controller or other dedicated controller of the wind turbine generator set.

[0032] 2A and 2B , the converter control method of a voltage source wind turbine generator system according to an embodiment of the present disclosure may include steps S201 to S204 .

[0033] In step S201, the given value U of the field weakening voltage can be used to gen_set , the input voltage of the wind turbine generator set's machine-side converter, and the converter's DC bus voltage measurement value U dc_measWith the DC bus voltage given value U dc_set , determine the reactive current given value I of the machine-side converter dref and active current given value I qref As mentioned above, the wind turbine generator set is a voltage source type wind turbine generator set.

[0034] Specifically, the field weakening voltage given value U gen_set The effective value of the input voltage of the generator-side converter U gen_meas The difference between them determines the reactive current given value I dref For example, U can be calculated gen_set with U gen_meas After the difference between the two is calculated, the reactive current set value I is obtained through the regulator (such as the weak magnetic link 211 shown in FIG2B ). dref Here, various existing regulators (such as but not limited to PI regulator) can be used to obtain the reactive current set value I dref , so its detailed description will be omitted. In addition, the weak magnetic voltage set value U can be predetermined in the design stage of the wind turbine generator set. gen_set , the present disclosure is for determining the given value of the weak magnetic voltage U gen_set There is no restriction on the method.

[0035] On the other hand, the DC bus voltage measurement value U dc_mes The difference between the DC bus voltage and the given value is U dc_set , determine the active current given value I qref For example, U can be calculated dc_meas with U dc_set After the difference between the two is calculated, the active current given value I is obtained through the regulator (such as the voltage link 212 shown in FIG2B ). dref As mentioned above, various existing regulators (such as but not limited to PI regulators) can be used to obtain the active current set value I qref , so its detailed description will be omitted.

[0036] In step S202, the active current given value I qref Determine the DC voltage damping output value D out According to an embodiment of the present disclosure, the DC voltage damping output value D out Used to determine the active power reference value P of the grid-side converter of the wind turbine generator set ref .

[0037] Specifically, the active current can be given a value I qref The product of the DC voltage damping output value D is determined by multiplying the DC voltage damping output value D by the preset proportional coefficient K. out , that is, D out =K*I qrefAs shown in FIG2B , the DC voltage damping output value D can be calculated by the damping generation link 213 out Here, the preset proportional coefficient K may be greater than -1 and less than 1, and the preset proportional coefficient K is not 0. The preset proportional coefficient may be preset by those skilled in the art according to actual needs, and the preset proportional coefficient K may be the same or different for different wind turbines.

[0038] In step S203, the reactive current given value I dref , Active current given value I qref and the input current of the machine-side converter to determine the modulation voltage reference value of the machine-side converter.

[0039] Specifically, the input current of the machine-side converter (for example, the three-phase input current i abc ) is transformed into the d-axis component I in the dq coordinate system (i.e., the two-phase rotating coordinate system) d and the q-axis component I q Then, the reactive current can be given by dref , Active current given value I qref and the d-axis component I d and the q-axis component I q Perform current outer loop control (such as the current outer loop 214 shown in FIG2B ) to determine the modulation voltage reference value, that is, the modulation voltage reference value U in the dq coordinate system. d and U q Here, the current outer loop control is a common control method in the converter control strategy of the voltage source type wind turbine generator set, so its detailed description will be omitted.

[0040] In step S204, the modulation voltage reference value U d and U q , which controls the operation of the machine-side converter.

[0041] According to an embodiment of the present disclosure, in order to control the operation of the machine-side converter, the converter control method for a voltage source wind turbine generator system according to an embodiment of the present disclosure may further include the following steps: determining a rotor position angle θ based on the input voltage and input current of the machine-side converter. Here, the input voltage and input current of the machine-side converter may be three-phase input voltage and three-phase input current, and various methods in the prior art may be used to determine the rotor position angle θ based on the three-phase input voltage and three-phase input current. Therefore, a detailed description thereof will be omitted. For example, as shown in FIG2B , the rotor position angle θ may be calculated by a rotor position estimation step 215 . Furthermore, the step of determining the rotor position angle does not have a sequential order with steps S201, S202, and S203 described above; it only needs to be performed before step S204.

[0042] Alternatively, in step S204, the modulation voltage reference value U of the generator-side converter may be used. d and U q And the rotor position angle θ, control the operation of the generator-side converter. For example, the modulation voltage reference value U in the dq coordinate system can be converted by coordinate transformation based on the rotor position angle θ. d and U q It is converted into a three-phase voltage in the abc coordinate system or a two-phase voltage in the αβ coordinate system, and then input into the modulation unit 216 (for example, but not limited to a space vector pulse width modulation unit) as shown in FIG2B for modulation, and the modulated three-phase voltage / two-phase voltage can be input into the machine-side converter to control the operation of the machine-side converter, thereby realizing the control of the DC bus voltage.

[0043] The converter control method of the voltage source wind turbine generator set shown in FIG. 2A may be executed in a machine-side converter controller as a machine-side converter control strategy, but the present disclosure is not limited thereto.

[0044] 3A and 3B , the converter control method of the voltage source wind turbine generator system according to the embodiment of the present disclosure may further include steps S301 to S304 .

[0045] In step S301, the torque given value T ref And the DC voltage damping output value D out , determine the active power reference value P ref .

[0046] Specifically, the wind turbine generator can be calculated based on the preset coefficient, the angular velocity ω and the flux linkage of the wind turbine generator. And the DC voltage damping output value D out , determine the first active power reference value component P1. For example, P1 = 1.5D outOn the other hand, it can be based on the preset coefficient, the number of generator pole pairs p, the torque given value T ref , and angular velocity ω, determine the second active power reference value component P2. For example, Here, the preset coefficient is shown as 1.5, but the present disclosure is not limited thereto. Thereafter, the active power reference value P may be determined based on the first active power reference value component P1 and the second active power reference value component P2. ref For example, P ref =P1+P2.

[0047] In step S302, the magnitude E of the virtual internal potential may be determined based on the reactive power / voltage command value, and the magnitude E of the virtual internal potential may be determined based on the active power reference value P ref and the active power measurement value P of the grid-side converter meas , determine the phase theta of the virtual internal potential. As shown in FIG3B , the amplitude E of the virtual internal potential can be determined by the reactive power / voltage link 311 based on the reactive power / voltage command value. For example, the reactive power / voltage link 311 can perform PI adjustment on the difference between the reactive power / voltage command value received from the main controller and the voltage feedback value of the grid-side converter to obtain the amplitude E of the virtual internal potential. Here, various methods in the prior art can be used to determine the amplitude of the virtual internal potential based on the reactive power / voltage command value, so their detailed description will be omitted. On the other hand, as shown in FIG3B , based on the active power reference value P ref and the active power measurement value P of the grid-side converter meas , the phase theta of the virtual internal potential is determined by the synchronization link 312. For example, the synchronization link 312 can be based on the active power deviation (ie, the active power reference value P ref and the active power measurement value P of the grid-side converter meas The virtual angular frequency deviation is determined based on the virtual angular frequency deviation and the rated angular frequency of the power grid, and the virtual angular frequency is determined based on the virtual angular frequency. Finally, the phase of the virtual internal potential is determined based on the virtual angular frequency. Here, various methods in the prior art can be used to determine the phase of the virtual internal potential based on the active power reference value P ref and the active power measurement value P of the grid-side converter meas The phase of the virtual internal potential is determined, so a detailed description thereof will be omitted.

[0048] In step S303, the modulation voltage reference value U of the grid-side converter can be determined according to the amplitude E and phase theta of the virtual internal potential and the predetermined virtual impedance. α_ref and U β_ref As shown in FIG3B , the modulation voltage reference value U in the two-phase stationary coordinate system (ie, αβ coordinate system) can be generated through the virtual impedance link 313 according to the amplitude E and phase theta of the virtual internal potential. α_ref and U β_refThe virtual impedance control technology is a common control method in voltage source wind turbine generators, so its detailed description is omitted here.

[0049] In step S304, the modulation voltage reference value U α_ref and U β_ref , to control the operation of the grid-side converter. For example, the modulation voltage reference value U α_ref and U β_ref The input is to the modulation unit 314 (such as but not limited to the space vector pulse width modulation unit) as shown in Figure 3B for modulation, and the modulated three-phase voltage / two-phase voltage can be input to the grid-side converter to control the operation of the grid-side converter and achieve voltage grid connection.

[0050] The converter control method of the voltage source wind turbine generator set shown in FIG3A may be executed in a grid-side converter controller as a grid-side converter control strategy, but the present disclosure is not limited thereto.

[0051] According to the converter control method of the voltage source wind turbine generator set as described above, when the wind turbine generator set is operating at high power, due to the addition of damping control, the converter DC bus voltage and generator torque can be kept stable, thereby reducing the trend of low-frequency oscillation divergence, reducing the risk of frequent starting of the converter braking resistor and shutdown caused by converter failure, and ensuring the stability of the wind turbine generator set during high-power operation.

[0052] Figure 4 is a block diagram illustrating a converter control device for a voltage source wind turbine generator system according to an embodiment of the present disclosure. Converter control device 400, as shown in Figure 4 , may be a converter control system (i.e., a generator-side converter controller and a grid-side converter controller) for a wind turbine generator system. However, the present disclosure is not limited thereto. Converter control device 400 may also be a main controller or other dedicated controller for a wind turbine generator system.

[0053] 4 , the converter control device 400 may include a current set value determination unit 401, a damping determination unit 402, a first voltage reference value determination unit 403, and a first control unit 404. Optionally, the converter control device 400 may further include a power reference value determination unit 405, a virtual internal potential determination unit 406, a second voltage reference value determination unit 407, and a second control unit 408.

[0054] The current setting value determination unit 401 can be based on the weak magnetic voltage setting value U gen_set , the input voltage of the wind turbine generator set's machine-side converter, and the converter's DC bus voltage measurement value U dc_meas With the DC bus voltage given value U dc_set , determine the reactive current given value I of the machine-side converter drefand active current given value I qref Specifically, the current given value determination unit 401 can be based on the weak magnetic voltage given value U gen_set The effective value of the input voltage of the generator-side converter U gen_meas The difference between them determines the reactive current given value I dref , and can be based on the DC bus voltage measurement value U dc_mes The difference between the DC bus voltage and the given value is U dc_set , determine the active current given value I qref .

[0055] The damping determination unit 402 may be based on the active current given value I qref Determine the DC voltage damping output value D out According to an embodiment of the present disclosure, the DC voltage damping output value D out Used to determine the active power reference value P of the grid-side converter of the wind turbine generator set ref Specifically, the damping determination unit 402 may set the active current to a given value I qref The product of the DC voltage damping output value D is determined by multiplying the DC voltage damping output value D by the preset proportional coefficient K. out , that is, D out =K*I qref Here, the preset proportional coefficient K may be greater than -1 and less than 1, and the preset proportional coefficient K is not zero.

[0056] The first voltage reference value determination unit 403 may be based on the reactive current given value I dref , Active current given value I qref Specifically, the first voltage reference value determination unit 403 can convert the input current of the machine-side converter (for example, the three-phase input current i abc ) is transformed into the d-axis component I in the dq coordinate system (i.e., the two-phase rotating coordinate system) d and the q-axis component I q , and can be obtained by setting the reactive current value I dref , Active current given value I qref and the d-axis component I d and the q-axis component I q Perform current outer loop control to determine the modulation voltage reference value, that is, the modulation voltage reference value U in the dq coordinate system d and U q .

[0057] The first control unit 404 can be configured to generate a voltage reference value U of the generator-side converter according to the modulation voltage reference value U d and U q, controlling the operation of the generator-side converter. Optionally, in order to control the operation of the generator-side converter, the first control unit 404 may further include a rotor position angle determination unit (not shown). The rotor position angle determination unit determines the rotor position angle θ based on the input voltage and input current of the generator-side converter. In this way, the first control unit 404 may determine the rotor position angle θ based on the modulation voltage reference value U of the generator-side converter. d and U q And the rotor position angle θ, control the operation of the generator-side converter. For example, the first control unit 404 can transform the modulation voltage reference value U in the dq coordinate system based on the rotor position angle θ through coordinate transformation. d and U q It is converted into a three-phase voltage in the abc coordinate system or a two-phase voltage in the αβ coordinate system, and then input into a modulation unit (such as but not limited to a space vector pulse width modulation unit) for modulation, and the modulated three-phase voltage / two-phase voltage can be input into the machine-side converter to control the operation of the machine-side converter, thereby realizing the control of the DC bus voltage.

[0058] The power reference value determination unit 405 may be based on the torque given value T ref And the DC voltage damping output value D out , determine the active power reference value P ref .

[0059] Specifically, the power reference value determination unit 405 may be based on a preset coefficient, the angular velocity ω of the generator of the wind turbine generator set, and the flux linkage. And the DC voltage damping output value D out , determine the first active power reference value component P1, and can be based on the preset coefficient, the number of generator pole pairs p, the torque given value T ref , and angular velocity ω, determine the second active power reference value component P2. Then, the power reference value determination unit 405 may determine the active power reference value P based on the first active power reference value component P1 and the second active power reference value component P2. ref .

[0060] The virtual internal potential determination unit 406 may determine the magnitude E of the virtual internal potential based on the reactive power / voltage command value and the active power reference value P. ref and the active power measurement value P of the grid-side converter meas , determine the phase theta of the virtual internal potential.

[0061] The second voltage reference value determination unit 407 can determine the modulation voltage reference value U of the grid-side converter according to the amplitude E and phase theta of the virtual internal potential and the predetermined virtual impedance. α_ref and U β_ref .

[0062] The second control unit 408 can be configured to generate a modulation voltage reference value U of the grid-side converter according to the modulation voltage reference value U α_ref and U β_ref , control the operation of the grid-side converter. For example, the second control unit 408 can modulate the voltage reference value U α_ref and U β_ref The input is to a modulation unit (such as but not limited to a space vector pulse width modulation unit) for modulation, and the modulated three-phase voltage / two-phase voltage can be input to the grid-side converter to control the operation of the grid-side converter and achieve voltage grid connection.

[0063] FIG5 is a block diagram illustrating a computing device according to an embodiment of the present disclosure. The computing device 500 may be implemented as a converter controller (i.e., a machine-side converter controller and a grid-side converter controller) of a voltage source wind turbine generator set. However, the present disclosure is not limited thereto. The computing device 500 may also be implemented as a main controller or other controller of a voltage source wind turbine generator set, or implemented in a main controller, converter controller, or other controller of a voltage source wind turbine generator set.

[0064] 5 , a computing device 500 according to an embodiment of the present disclosure may include a processor 510 and a memory 520. The processor 510 may include (but is not limited to) a central processing unit (CPU), a digital signal processor (DSP), a microcomputer, a field programmable gate array (FPGA), a system on a chip (SoC), a microprocessor, an application-specific integrated circuit (ASIC), etc. The memory 520 stores computer programs to be executed by the processor 510. The memory 520 includes a high-speed random access memory and / or a non-volatile computer-readable storage medium. When the processor 510 executes the computer program stored in the memory 520, the converter control method for a voltage source wind turbine generator set as described above may be implemented.

[0065] Optionally, the computing device 500 may communicate with various components in the voltage source wind turbine generator set in a wired / wireless manner, and may also communicate with the voltage source wind turbine generator set and / or devices outside the wind farm in a wired / wireless manner.

[0066] According to an embodiment of the present disclosure, a voltage source type wind turbine generator set is provided, wherein the voltage source type wind turbine generator set includes the converter control device or the computing device as described above.

[0067] The converter control method of the voltage source wind turbine generator set according to the embodiment of the present disclosure can be written as a computer program and stored on a computer-readable storage medium. When the computer program is executed by a processor, the converter control method of the voltage source wind turbine generator set as described above can be implemented. Examples of computer-readable storage media 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 disk storage, hard disk drive (HDD), solid state drive (SSD), card storage (such as, multimedia card, secure digital (SD) card or ultra fast digital (XD) card), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid state disk and any other device, any other device is configured to store the computer program and any associated data, data files and data structures in a non-transitory manner and 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. In one example, the computer program and any associated data, data files and data structures are distributed on a networked computer system so that the computer program and any associated data, data files and data structures are stored, accessed and executed in a distributed manner by one or more processors or computers.

[0068] FIG6 is a graph showing the DC bus voltage and generator torque value of a conventional voltage source wind turbine generator set without damping control when operating at high power.

[0069] Referring to Figure 6, when an existing undamped voltage source wind turbine generator set operates at high power, the DC bus voltage gradually exhibits low-frequency oscillation divergence (as shown by curve 601), with the maximum DC bus voltage increasing from 2025V in normal operation to 2140V. Simultaneously, the generator torque value continues to exhibit low-frequency oscillations when it reaches 42,500 N·m (as shown by curve 602). This indicates that existing undamped voltage source wind turbine generator sets cannot meet the requirements for normal steady-state operation at high power. The continued oscillation divergence of the DC bus voltage will lead to DC bus voltage overvoltage, and further increases in the generator torque oscillation amplitude will seriously deteriorate the wind turbine generator set's operating performance and the stability of the converter control.

[0070] FIG7 is a graph showing a DC bus voltage and a generator torque value of a voltage source wind turbine generator set according to an embodiment of the present disclosure when operating at high power.

[0071] Referring to Figure 7 , when a voltage-source wind turbine operates at high power, the DC bus voltage remains stable at approximately 2030V (as shown by curve 701) due to damping control, eliminating the tendency for low-frequency oscillations to diverge. This significantly reduces the risk of frequent activation of the converter's braking resistor and converter shutdowns due to faults. Furthermore, the generator torque remains stable at 45,000 N·m (as shown by curve 702), ensuring the stability of the wind turbine during high-power operation.

[0072] According to the converter control method and control device of the voltage source wind turbine generator set in the embodiment of the present disclosure, damping control is achieved by calculating the damping output value in the machine-side control strategy of the converter controller and applying the damping output value in the grid-side control strategy, thereby improving the control stability of the voltage source wind turbine generator set during high-power operation, avoiding the problem of low-frequency oscillation divergence of the converter DC bus voltage and generator torque, effectively reducing the risk of frequent starting of the converter braking resistor and converter fault shutdown, and reducing the power generation loss caused by faults of the wind turbine generator set.

[0073] While some embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for controlling a converter of a voltage source wind turbine generator set, the method comprising: Determine a reactive current given value and an active current given value of the machine-side converter based on a weak magnetic voltage given value, an input voltage of the machine-side converter, and a DC bus voltage measurement value and a DC bus voltage given value of the converter; Determining a DC voltage damping output value based on the active current given value, wherein the DC voltage damping output value is used to determine an active power reference value of a grid-side converter of the wind turbine generator set; Determining a modulation voltage reference value of the machine-side converter based on the reactive current given value, the active current given value and the input current of the machine-side converter; The operation of the generator-side converter is controlled according to the modulation voltage reference value of the generator-side converter.

2. The converter control method according to claim 1, wherein: The converter control method further comprises: Determining the active power reference value based on the torque given value and the DC voltage damping output value; Determining the magnitude of the virtual internal potential based on the reactive power / voltage command value, and determining the phase of the virtual internal potential based on the active power reference value and the active power measurement value of the grid-side converter; Determining a modulation voltage reference value of the grid-side converter according to the amplitude and phase of the virtual internal potential and a predetermined virtual impedance; The operation of the grid-side converter is controlled according to the modulation voltage reference value of the grid-side converter.

3. The converter control method according to claim 1, wherein: The converter control method further comprises: Determining a rotor position angle according to an input voltage and an input current of the machine-side converter; Among them, the step of controlling the operation of the machine-side converter according to the modulation voltage reference value of the machine-side converter includes: controlling the operation of the machine-side converter according to the modulation voltage reference value of the machine-side converter and the rotor position angle.

4. The converter control method according to claim 1, wherein: The steps of determining the reactive current set value and the active current set value of the machine-side converter include: Determining the reactive current given value based on the difference between the magnetic weakening voltage given value and the effective value of the input voltage of the machine-side converter; The active current given value is determined based on a difference between the DC bus voltage measurement value and the DC bus voltage given value.

5. The converter control method according to claim 1, wherein: The step of determining the DC voltage damping output value includes: determining the product of the active current given value and a preset proportional coefficient as the DC voltage damping output value.

6. The converter control method according to claim 1, wherein: The step of determining the modulation voltage reference value of the generator-side converter comprises: The input current of the machine-side converter is transformed into a d-axis component and a q-axis component in a dq coordinate system by coordinate transformation; The modulation voltage reference value is determined by performing current outer loop control on the reactive current set value, the active current set value, the d-axis component, and the q-axis component.

7. The converter control method according to claim 2, wherein: The step of determining the active power reference value comprises: Determining a first active power reference value component based on a preset coefficient, an angular velocity and a flux linkage of a generator of the wind turbine generator set, and the DC voltage damping output value; Determining a second active power reference value component based on the preset coefficient, the number of generator pole pairs, the torque given value, and the angular velocity; The active power reference value is determined based on the first active power reference value component and the second active power reference value component.

8. A converter control device for a voltage source wind turbine generator set, the converter control device comprising: A current set value determination unit is configured to determine a reactive current set value and an active current set value of the machine-side converter based on a weak magnetic voltage set value, an input voltage of the machine-side converter, and a DC bus voltage measurement value and a DC bus voltage set value of the converter; A damping determination unit is configured to: determine a DC voltage damping output value based on the active current given value, wherein the DC voltage damping output value is used to determine an active power reference value of a grid-side converter of the wind turbine generator set; A first voltage reference value determining unit is configured to: determine a modulation voltage reference value of the machine-side converter based on the reactive current given value, the active current given value and the input current of the machine-side converter; The first control unit is configured to: control the Control the operation of the machine-side converter.

9. The converter control device according to claim 8, wherein: The converter control device further comprises: A power reference value determination unit is configured to: determine the active power reference value based on a torque given value and the DC voltage damping output value; a virtual internal potential determination unit configured to: determine the magnitude of the virtual internal potential based on the reactive power / voltage command value, and determine the phase of the virtual internal potential based on the active power reference value and the active power measurement value of the grid-side converter; a second voltage reference value determining unit, configured to: determine a modulation voltage reference value of the grid-side converter according to the amplitude and phase of the virtual internal potential and a predetermined virtual impedance; The second control unit is configured to control the operation of the grid-side converter according to the modulation voltage reference value of the grid-side converter.

10. The converter control device according to claim 8, wherein: The converter control device further comprises: A rotor position angle determination unit is configured to: determine a rotor position angle according to an input voltage and an input current of the generator-side converter; The first control unit is configured to control the operation of the generator-side converter according to a modulation voltage reference value of the generator-side converter and the rotor position angle.

11. The converter control device according to claim 8, wherein: The current setpoint determination unit is configured as follows: Determining the reactive current given value based on the difference between the magnetic weakening voltage given value and the effective value of the input voltage of the machine-side converter; The active current given value is determined based on a difference between the DC bus voltage measurement value and the DC bus voltage given value.

12. The converter control device according to claim 8, wherein: The damping determination unit is configured to determine the product of the active current given value and a preset proportional coefficient as the DC voltage damping output value.

13. A computing device, the computing device comprising: processor; A memory storing a computer program, when the computer program is executed by a processor, implements the converter control method of a voltage source type wind turbine generator set according to any one of claims 1 to 7 Law.

14. The computing device of claim 13, wherein: The computing device is a converter controller of a voltage source wind turbine generator set.

15. A voltage source type wind turbine generator set, comprising the converter control device according to any one of claims 8 to 12, or the calculation device according to claim 13 or 14.

Images