Converter control method and control device of voltage source type wind generating set

Abstract

The invention provides a converter control method and device of a voltage source type wind generating set. The converter control method comprises the following steps: determining a reactive current given value and an active current given value of a machine side converter based on a weak magnetic voltage given value, an input voltage of the machine side converter of the wind generating set, and a direct current bus voltage measurement value and a direct current bus voltage given value of the converter; a DC voltage damping output value is determined based on the active current given value, and the DC voltage damping output value is used for determining an active power reference value of a grid-side converter of the wind generating 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; and controlling the operation of the machine-side converter according to the modulation voltage reference value of the machine-side converter.

Description

Technical Field

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

[0002] A wind turbine is a device that converts wind energy into electrical energy. In a voltage source wind turbine, the machine-side converter converts the AC power output by the wind turbine into DC power to control the DC bus voltage, while the grid-side converter uses virtual synchronous power generation control technology to convert DC power into AC power. However, in the prior art, the machine-side converter and the grid-side converter are usually controlled independently, without considering the difference in control performance between the machine-side converter and the grid-side converter when the converter is running. Summary of the invention

[0003] 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.

[0004] In a general aspect, a converter control method for a voltage source wind 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 a DC bus voltage of the converter 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 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.

[0005] Optionally, the converter control method also includes: determining the active power reference value based on the torque given value and the DC voltage damping output value; determining the amplitude of the virtual internal potential based on the reactive / 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 the 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; and controlling the operation of the grid-side converter according to the modulation voltage reference value of the grid-side converter.

[0006] Optionally, the converter control method also includes: determining the rotor position angle based on the input voltage and input current of the machine-side converter; wherein, the step of controlling the operation of the machine-side converter based on the modulation voltage reference value of the machine-side converter includes: controlling the operation of the machine-side converter based on the modulation voltage reference value of the machine-side converter and the rotor position angle.

[0007] Optionally, the step of determining the reactive current set value and the active current set value of the machine-side converter includes: determining the reactive current set value based on the difference between the weak magnetic voltage set value and the effective value of the input voltage of the machine-side converter; and determining the active current set value based on the difference between the DC bus voltage measurement value and the DC bus voltage set value.

[0008] Optionally, the step of determining the DC voltage damping output value includes: determining the DC voltage damping output value as the product of the active current given value and a preset proportional coefficient.

[0009] Optionally, the step of determining the modulation voltage reference value of the machine-side converter includes: transforming the input current of the machine-side converter into a d-axis component and a q-axis component in a dq coordinate system through coordinate transformation; and determining the modulation voltage reference value by performing current outer loop control on the reactive current set value, the active current set value, and the d-axis component and the q-axis component.

[0010] Optionally, the step of determining the active power reference value includes: determining a first active power reference value component based on a preset coefficient, the angular velocity and magnetic flux of the 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 set value, and the angular velocity; and determining the active power reference value based on the first active power reference value component and the second active power reference value component.

[0011] In another general aspect, a converter control device for a voltage source type wind 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 a 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 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.

[0012] Optionally, the converter control device also includes: a power reference value determination unit, configured to determine the active power reference value based on the torque given value and the DC voltage damping output value; a virtual internal potential determination unit, configured to determine the amplitude of the virtual internal potential based on the reactive / 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 determination unit, configured to determine the 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; a second control unit, configured to control the operation of the grid-side converter according to the modulation voltage reference value of the grid-side converter.

[0013] Optionally, the converter control device also includes: a rotor position angle determination unit, configured to determine the rotor position angle according to the input voltage and input current of the machine-side converter; wherein the first control unit is configured to control the operation of the machine-side converter according to the modulation voltage reference value of the machine-side converter and the rotor position angle.

[0014] Optionally, the current set value determination unit is configured to: determine the reactive current set value based on the difference between the weak magnetic voltage set value and the effective value of the input voltage of the machine-side converter; determine the active current set value based on the difference between the DC bus voltage measurement value and the DC bus voltage set value.

[0015] Optionally, the damping determination unit is configured to: determine the product of the active current set value and a preset proportional coefficient as the DC voltage damping output value.

[0016] In another general aspect, a computing device is provided, the computing device comprising: a processor; a memory storing a computer program, and 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.

[0017] Optionally, the computing device is a converter controller of a voltage source wind turbine generator set.

[0018] In another general aspect, a voltage source type wind turbine generator set is provided, characterized in that the voltage source type wind turbine generator set comprises the converter control device as described above or the computing device as described above.

[0019] According to the converter control method and control device of the voltage source wind generator set of 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 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 of the wind generator set due to faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 is a schematic block diagram showing a converter control strategy for a wind turbine generator system.

[0022] Figure 2A is a flow chart showing a converter control method of a voltage source wind turbine generator set according to an embodiment of the present disclosure, Figure 2B Detailed description is a schematic block diagram showing a converter control method of a voltage source wind turbine generator system according to an embodiment of the present disclosure.

[0023] Figure 3A is a flow chart showing a converter control method of a voltage source wind turbine generator set according to another embodiment of the present disclosure, Figure 3B is a schematic block diagram showing a converter control method of a voltage source wind turbine generator set according to another embodiment of the present disclosure.

[0024] Figure 4 Detailed description is a block diagram showing a converter control device of a voltage source type wind turbine generator system according to an embodiment of the present disclosure.

[0025] Figure 5 is a block diagram illustrating a computing device according to an embodiment of the present disclosure.

[0026] Figure 6 The graph 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.

[0027] Figure 7 is a graph showing a DC bus voltage and a generator torque value when a voltage source wind turbine generator set according to an embodiment of the present disclosure operates at high power. DETAILED DESCRIPTION

[0028] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be clear. For example, the order of operations described herein is only 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 simplicity, the description of features known in the art may be omitted.

[0029] The features described herein can be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided to illustrate only some of the many possible ways to implement the methods, devices, and / or systems described herein, which will be clear after understanding the disclosure of the present application.

[0030] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more.

[0031] 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 only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, first component, first region, first layer, or first portion referred to in the examples may also be referred to as the second member, second component, second region, second layer, or second portion.

[0032] In the specification, when an element (such as a layer, a region or a substrate) is described as being “on”, “connected to” or “coupled to” another element, the element may be directly “on”, “connected to” or “coupled to” another 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.

[0033] The terms used herein are only used to describe various examples and are not intended to limit the disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "comprise", "include" and "have" indicate the presence of the described features, quantities, operations, components, elements and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements and / or combinations thereof.

[0034] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by a person of ordinary skill in the art to which the present disclosure belongs after understanding the present disclosure. Unless explicitly defined as such herein, terms (such as those defined in a general dictionary) 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.

[0035] Furthermore, in the description of examples, when it is considered that a detailed description of a well-known related structure or function would cause vague interpretation of the present disclosure, such a detailed description will be omitted.

[0036] The converter of a wind turbine generator set includes a machine-side converter and a grid-side converter. When the converter is running 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 usually tens of hertz, so as to ensure that the voltage can be quickly and dynamically adjusted when the wind turbine generator set transmits power to the grid. On the other hand, the grid-side converter adopts virtual synchronous power generation control technology, and the internal potential (i.e., virtual internal potential) generated by this virtual synchronous power generation control technology has slow dynamic characteristics, and the control bandwidth required is usually less than 5 hertz. In this way, the inconsistency of the control bandwidth on the machine-grid side leads to a large machine-grid side power difference in the DC capacitor, which in turn leads to continuous low-frequency oscillation of the DC bus voltage and generator torque of the converter. The low-frequency oscillation of the generator torque will have a bad effect on the wind turbine drive chain system, and the low-frequency oscillation of the DC bus voltage will cause the frequent startup of the converter brake resistor until the converter detects a fault and trips. Therefore, when the converter is running at high power, the wind turbine will not be able to operate normally in a steady state, which seriously reduces the service life of the converter brake resistor and also increases the loss of wind turbine power generation.

[0037] On the other hand, when the wind turbine is running at high power, when the wind speed fluctuates greatly, the power fluctuation on the machine side will be large. At this time, the machine-side converter needs to quickly adjust the DC bus voltage to achieve rapid power control on the machine side. On the other hand, the grid-side converter uses a virtual synchronous generator (VSG) control method with slow dynamic characteristics. The operating bandwidth of the reactive / voltage link and the synchronous link is small, and the response speed of the grid-side power control is slower than that of the machine-side power control; thus, the electrical-mechanical coupling of the wind turbine is deteriorated when the wind turbine is running at high power. At the same time, the DC capacitor of the converter is prone to unbalanced power, resulting in the divergence of the generator torque and the low-frequency oscillation of the DC bus voltage. When the DC bus voltage oscillates too severely, the converter braking resistor will be activated, and the strong oscillation of the generator torque will reduce the stability of the wind turbine transmission chain. Therefore, the wind turbine will shut down due to the safety protection triggered by the low-frequency oscillation state.

[0038] To this end, an embodiment of the present disclosure provides a converter control method and a 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, so as to improve 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.

[0039] Figure 1 is a schematic block diagram showing a converter control strategy for a wind turbine generator system.

[0040] Reference Figure 1 , the control system of the 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 one controller or may be separately provided. Signals can be transmitted between the machine-side converter controller and the grid-side converter controller. During the control process of the wind turbine generator set, the main controller may send a pitch angle instruction to the pitch controller to adjust the mechanical torque of the impeller. At the same time, the main controller may send control instructions to the current conversion control system, and the machine-side converter controller and the grid-side converter controller may respectively control the operation of the machine-side converter and the grid-side converter according to the control instructions sent by the main controller. Furthermore, the machine-side converter controller may feedback the generator speed and electromagnetic torque of the wind turbine generator set to the main controller, and the main controller may send a torque / power given instruction to the grid-side converter controller according to the generator speed and electromagnetic torque, and the grid-side converter controller may perform torque control on the generator according to the torque / power given instruction, and control the grid-connected power of the wind turbine generator set. Note that, Figure 1 The converter of the wind turbine generator set shown in FIG. 1 is a three-level converter, but the present disclosure is not limited thereto.

[0041] Figure 2A is a flow chart showing a converter control method of a voltage source wind turbine generator set according to an embodiment of the present disclosure, Figure 2B Detailed description is a schematic block diagram showing a converter control method of a voltage source wind turbine generator system according to an embodiment of the present disclosure. Figure 3A is a flow chart showing a converter control method of a voltage source wind turbine generator set according to another embodiment of the present disclosure, Figure 3B 1 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 implemented by a converter controller of the wind turbine generator set (i.e., Figure 1 The converter control system shown in FIG. 1 includes a machine-side converter controller and a grid-side converter controller). However, the present disclosure is not limited thereto. The converter control method of the voltage source wind turbine generator set may also be executed by a main controller or other dedicated controller of the wind turbine generator set.

[0042] Reference Figure 2A and Figure 2B According to an embodiment of the present disclosure, the converter control method of a voltage source wind turbine generator set may include steps S201 to S204.

[0043] In step S201, based on the field weakening voltage given 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 set 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.

[0044] Specifically, based on the field weakening voltage given value U gen_set The effective value of the input voltage of the machine-side converter is U gen_meas The difference between the two determines the reactive current given value I dref For example, U can be calculated gen_set with U gen_meas After the difference between Figure 2B The weak magnetic link 211 shown in FIG. 2 obtains the reactive current given value I dref Here, various existing regulators (such as but not limited to PI regulators) 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 useful for determining the given value U of the weak magnetic voltage gen_set There is no restriction on the method.

[0045] 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 Figure 2B The voltage link 212 shown in FIG. 1 obtains the active current given value I 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.

[0046] In step S202, 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.

[0047] Specifically, the active current 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 .like Figure 2B As shown in FIG. 2 , 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.

[0048] In step S203, based on 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.

[0049] 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 set to 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 (such as the current outer loop 214 shown in FIG. 2B ) 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.

[0050] In step S204, the modulation voltage reference value U d and U q , control the operation of the machine-side converter.

[0051] According to an embodiment of the present disclosure, in order to control the operation of the machine-side converter, the converter control method of the voltage source type wind turbine generator set according to the embodiment of the present disclosure may further include the following steps: determining the rotor position angle θ according to 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 a three-phase input voltage and a three-phase input current, and various methods in the prior art may be used to determine the rotor position angle θ according to the three-phase input voltage and the three-phase input current, so the detailed description thereof will be omitted. For example, Figure 2B As shown in , the rotor position angle θ can be calculated by the rotor position estimation link 215. On the other hand, there is no sequence between the step of determining the rotor position angle and the above steps S201, S202 and S203, and it only needs to be performed before step S204.

[0052] Optionally, in step S204, the modulation voltage reference value U d and U q And the rotor position angle θ, control the operation of the machine-side converter. For example, the modulation voltage reference value U in the dq coordinate system can be transformed based on the rotor position angle θ through coordinate transformation. d and U q Convert to three-phase voltage in abc coordinate system or two-phase voltage in αβ coordinate system, and then input to Figure 2B The modulation unit 216 shown in the figure (for example, but not limited to a space vector pulse width modulation unit) is used 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.

[0053] like Figure 2A The converter control method of the voltage source wind turbine generator set shown may be executed in a machine-side converter controller as a machine-side converter control strategy, but the present disclosure is not limited thereto.

[0054] Reference Figure 3A and Figure 3B According to the embodiment of the present disclosure, the converter control method of the voltage source wind turbine generator set may further include steps S301 to S304.

[0055] In step S301, 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 .

[0056] Specifically, the wind turbine generator system can be based on the preset coefficient, the angular velocity ω of the generator and the flux linkage. And the DC voltage damping output value D out, determine the first active power reference value component P1. For example, P1 = 1.5D out On 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.

[0057] 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 measured active power value P of the grid-side converter meas , determine the phase theta of the virtual internal potential. Figure 3B As shown in , the amplitude E of the virtual internal potential can be determined by the reactive / voltage link 311 based on the reactive / voltage command value. For example, the reactive / voltage link 311 can perform PI adjustment on the difference between the reactive / 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 / voltage command value, so the detailed description thereof will be omitted. On the other hand, as Figure 3B As shown in ref and the measured active power 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 may be based on the active power deviation (ie, the active power reference value P ref and the measured active power value P of the grid-side converter meas The virtual angular frequency deviation is determined by calculating the difference between the virtual angular frequency deviation and the rated angular frequency of the power grid, and then 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 measured active power value P of the grid-side converter meas The phase of the virtual internal potential is determined, so its detailed description will be omitted.

[0058] 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 .like Figure 3BAs shown in FIG, according to the amplitude E and phase theta of the virtual internal potential, the modulation voltage reference value U in the two-phase stationary coordinate system (ie, the αβ coordinate system) can be generated through the virtual impedance link 313. α_ref and U β_ref The virtual impedance control technology is a common control method in voltage source wind turbine generator sets, so its detailed description is omitted here.

[0059] 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 Input to Figure 3B The modulation unit 314 (such as but not limited to the space vector pulse width modulation unit) shown in the figure is modulated, and the modulated three-phase voltage / two-phase voltage can be input into the grid-side converter to control the operation of the grid-side converter and realize voltage grid connection.

[0060] like Figure 3A The converter control method of the voltage source wind turbine generator set shown may be executed in a grid-side converter controller as a grid-side converter control strategy, but the present disclosure is not limited thereto.

[0061] According to the converter control method of the voltage source wind turbine generator set as described above, when the wind turbine generator set is running 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 due to converter failure, and ensuring the stability of the wind turbine generator set when running at high power.

[0062] Figure 4 1 is a block diagram showing a converter control device of a voltage source type wind turbine generator set according to an embodiment of the present disclosure. Figure 4 The converter control device 400 shown in the figure may be a converter control system of a wind turbine generator set (ie, a machine-side converter controller and a grid-side converter controller). However, the present disclosure is not limited thereto. The converter control device 400 may also be a main controller or other dedicated controller of a wind turbine generator set.

[0063] Reference Figure 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 also 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.

[0064] The current given value determination unit 401 can be based on the weak magnetic voltage given 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 set value I of the machine-side converter dref and active current given value I qref Specifically, the current given value determination unit 401 may be based on the weak magnetic voltage given value U gen_set The effective value of the input voltage of the machine-side converter is U gen_meas The difference between the reactive current and the reactive current is determined by 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 .

[0065] 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 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.

[0066] 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 qPerform 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 .

[0067] The first control unit 404 may 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 machine-side converter. Optionally, in order to control the operation of the machine-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 according to the input voltage and input current of the machine-side converter. In this way, the first control unit 404 may determine the rotor position angle θ according to the modulation voltage reference value U of the machine-side converter. d and U q and the rotor position angle θ to control the operation of the generator-side converter. For example, the first control unit 404 may transform the modulation voltage reference value U in the dq coordinate system based on the rotor position angle θ by 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.

[0068] 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 .

[0069] Specifically, the power reference value determination unit 405 may be based on a preset coefficient, an angular velocity ω of the generator of the wind turbine generator set, and a 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 the 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 .

[0070] 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 based on the active power reference value P ref and the measured active power value P of the grid-side converter meas , determine the phase theta of the virtual internal potential.

[0071] The second voltage reference value determination unit 407 may 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 .

[0072] 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 voltage is input 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 a grid-side converter to control the operation of the grid-side converter and achieve voltage grid connection.

[0073] Figure 5 5 is a block diagram showing 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.

[0074] Reference Figure 5 According to an embodiment of the present disclosure, the computing device 500 may include a processor 510 and a memory 520. The processor 510 may include (but 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 a computer program 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 of the voltage source wind turbine generator set as described above can be implemented.

[0075] Optionally, the computing device 500 may communicate with various components in the voltage source wind turbine generator set in a wired / wireless communication manner, and may also communicate with the voltage source wind turbine generator set and / or devices outside the wind farm in a wired / wireless communication manner.

[0076] According to an embodiment of the present disclosure, a voltage source type wind turbine generator set may be provided. The voltage source type wind turbine generator set includes the converter control device as described above or the calculation device as described above.

[0077] 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 extreme 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 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.

[0078] Figure 6 The graph 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.

[0079] Reference Figure 6When the existing voltage source wind turbine generator set without damping control is running at high power, the DC bus voltage gradually shows low-frequency oscillation divergence (as shown by curve 601), and the maximum value of the DC bus voltage increases from 2025V in normal operation to 2140V. At the same time, the generator torque value continues to have low-frequency oscillation when it reaches 42500N·m (as shown by curve 602). It can be seen that the existing voltage source wind turbine generator set without damping control cannot meet the requirements of normal steady-state operation under high power. The continuous oscillation divergence of the DC bus voltage will cause the DC bus voltage to be overvoltage, and the further increase of the generator torque oscillation amplitude will seriously deteriorate the operating performance of the wind turbine generator set and the stability of the converter control.

[0080] Figure 7 is a graph showing a DC bus voltage and a generator torque value when a voltage source wind turbine generator set according to an embodiment of the present disclosure operates at high power.

[0081] Reference Figure 7 When the voltage source wind turbine generator set is running at high power, due to the application of damping control, the DC bus voltage can be stabilized at around 2030V (as shown in curve 701), without the trend of low-frequency oscillation divergence, which greatly reduces the risk of frequent startup of the converter braking resistor and converter failure shutdown. At the same time, the generator torque can run stably at 45000N·m (as shown in curve 702), thus ensuring the stability of the wind turbine generator set under high power operation.

[0082] According to the converter control method and control device of the voltage source wind generator set of 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 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 of the wind generator set due to faults.

[0083] Although some embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that modifications may be made to the embodiments without departing from the principles and spirit of the present 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, characterized in that: The converter control method comprises: 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, characterized in that: 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, characterized in that: 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, characterized in that: 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 weak magnetic 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, characterized in that: 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, characterized in that: 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, characterized in that: 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, characterized in that: The converter control device comprises: 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 operation of the generator-side converter according to a modulation voltage reference value of the generator-side converter.

9. The converter control device according to claim 8, characterized in that: 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, characterized in that: 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, characterized in that: The current setpoint determination unit is configured as follows: Determining the reactive current given value based on the difference between the weak magnetic 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, characterized in that: 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, characterized in that: The computing device comprises: processor; A memory storing a computer program, which, when executed by a processor, implements the converter control method of a voltage source wind turbine generator set according to any one of claims 1 to 7.

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 wind turbine generator set, characterized in that: The voltage source wind turbine generator set comprises the converter control device according to any one of claims 8 to 12, or the calculation device according to claim 13 or 14.

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