A method and device for generating control signal of voltage source type AC / DC converter

Abstract

The present application discloses a method and device for generating a control signal of a voltage source AC / DC converter, the method comprising: generating two modulation voltage amplitudes according to a DC voltage parameter value and a grid-connected reactive power parameter value, the two modulation voltage amplitudes being input signals of the first position and the second position of a first gate switch respectively; controlling the first gate switch to output a gated modulation voltage amplitude through a first mode control signal; obtaining the input signals of the first position and the second position of the second gate switch according to a preset gain ratio, an integrator and a phase-locked loop, and controlling the second gate switch to output a gated phase through a second mode control signal; generating a pulse control signal of a target voltage source AC / DC converter according to the gated modulation voltage amplitude and the gated phase, for switching different preset grid control modes. The present application can solve the technical problem that the existing control technology cannot simultaneously meet the stability requirements under weak grid conditions and strong grid conditions.

Description

Technical Field

[0001] The present application relates to the technical field of power distribution network control, and in particular to a method and device for generating a control signal of a voltage source AC / DC converter. Background Art

[0002] The high penetration of distributed renewable energy has brought great challenges to the operation and dispatch of traditional AC distribution networks. The uncertainty of distributed energy and loads in power generation and demand makes the distribution network prone to voltage over-limit, feeder power imbalance and other problems, reducing the safety and reliability of the distribution network. In order to overcome the above-mentioned shortcomings, the distribution network is often regulated by traditional regulation methods, such as on-load voltage regulation, capacitor bank switching, distributed energy scheduling planning and reconstruction. However, the regulation speed and accuracy of these regulation methods are limited. For this reason, flexible interconnected distribution networks have received widespread attention. Flexible interconnected distribution networks use intelligent soft switches to replace traditional interconnection switches to achieve flexible interconnection of multiple adjacent distribution networks. The ability of intelligent soft switches to continuously adjust power flow can effectively solve problems such as power flow transmission, load balancing and voltage management between feeders.

[0003] See also Figure 3 , wind power, photovoltaic and other new energy sources are mostly connected to the power grid through voltage source DC / AC converters. Voltage source DC / AC converters usually use a vector control method with a phase-locked loop to observe the grid voltage phase, showing the external characteristics of a current source. Vector-controlled converters have good stability under strong grid conditions, but the stability margin gradually decreases under weak grid conditions, which can easily cause problems such as low-frequency oscillation, subsynchronous oscillation, harmonic oscillation, and endanger the safe and stable operation of the grid. Network-based control can make the converter show the external characteristics of a voltage source, and has the function of actively supporting the grid. It has strong stability under weak grid conditions, but the stability margin decreases under strong grids. Therefore, it is necessary to develop a mode switching control system that enables the converter to have strong stability under both strong and weak grids. Summary of the invention

[0004] The present application provides a method and device for generating a control signal for a voltage source AC / DC converter, which is used to solve the technical problem that the existing control technology cannot simultaneously meet the stability requirements under weak grid conditions and strong grid conditions.

[0005] In view of this, the first aspect of the present application provides a method for generating a control signal of a voltage source AC / DC converter, comprising:

[0006] Generate a first modulation voltage amplitude and a second modulation voltage amplitude respectively according to a DC voltage parameter value and a grid-connected reactive power parameter value;

[0007] Using the first modulation voltage amplitude as an input signal of a first position of a first gate switch, and using the second modulation voltage amplitude as an input signal of a second position of the first gate switch;

[0008] Controlling the control flag of the first gating switch through a first mode control signal, and outputting a gating modulation voltage amplitude;

[0009] After acquiring the input signal of the first position and the input signal of the second position of the second gating switch according to the preset gain ratio, the integrator and the phase-locked loop, the control flag of the second gating switch is controlled by the second mode control signal, and the gating phase is output;

[0010] A pulse control signal of a target voltage source AC / DC converter is generated according to the gated modulation voltage amplitude and the gated phase, and is used for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid following control mode and a grid forming control mode.

[0011] Preferably, the generating of the first modulation voltage amplitude and the second modulation voltage amplitude according to the DC voltage parameter value and the grid-connected reactive power parameter value respectively comprises:

[0012] A PI regulator is used to generate a d-axis component of a modulation voltage according to a DC voltage parameter value, wherein the DC voltage parameter value includes a voltage feedback value and a voltage reference value;

[0013] The PI regulator is used to generate a q-axis component of the modulation voltage according to a grid-connected reactive power parameter value, wherein the grid-connected reactive power parameter value includes a reactive feedback value and a reactive reference value;

[0014] Generate a modulation voltage amplitude according to the d-axis component and the q-axis component to obtain a first modulation voltage amplitude;

[0015] The PI regulator is used to generate a second modulation voltage amplitude according to the grid-connected reactive power parameter value and the initial voltage value.

[0016] Preferably, controlling the control flag of the first gating switch by the first mode control signal and outputting the gating modulation voltage amplitude includes:

[0017] Controlling the control flag of the first selection switch by a first mode control signal to obtain an output voltage amplitude;

[0018] The output voltage amplitude is limited by a preset change rate to obtain a gate modulation voltage amplitude.

[0019] Preferably, the step of controlling the control flag of the first selection switch by the first mode control signal to obtain the output voltage amplitude further includes:

[0020] A preset mode control module is used to obtain a first mode control signal according to the short-circuit ratio of the grid connection point.

[0021] Preferably, after obtaining the input signal of the first position and the input signal of the second position of the second gating switch according to the preset gain ratio, the integrator and the phase-locked loop, the control flag of the second gating switch is controlled by the second mode control signal, and the gating phase is output, including:

[0022] After processing the DC voltage parameter value with a preset gain ratio, performing signal processing through an integrator to obtain an output phase, and using the output phase as an input signal for the second position of the second selection switch;

[0023] A phase-locked loop is used to detect the grid-connected phase of the grid-connected point voltage, and the grid-connected phase is used as an input signal of the first position of the second selection switch;

[0024] The control flag of the second selection switch is controlled by the second mode control signal to output the selection phase.

[0025] Preferably, the pulse control signal of the target voltage source type AC / DC converter is generated according to the gated modulation voltage amplitude and the gated phase, and is used for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid-following control mode and a grid-forming control mode, including:

[0026] generating a sinusoidal modulation voltage signal according to the gated modulation voltage amplitude and the gated phase;

[0027] Performing pulse width modulation on the sinusoidal modulated voltage signal to generate a pulse control signal for a target voltage source type AC / DC converter;

[0028] Based on the pulse control signal, switching of different preset network type control modes is realized, and the preset network type control modes include a network following control mode and a network building control mode.

[0029] A second aspect of the present application provides a voltage source AC / DC converter control signal generating device, comprising:

[0030] An amplitude generating unit, used to generate a first modulation voltage amplitude and a second modulation voltage amplitude respectively according to a DC voltage parameter value and a grid-connected reactive power parameter value;

[0031] a signal definition unit, configured to use the first modulation voltage amplitude as an input signal of a first position of a first selection switch, and the second modulation voltage amplitude as an input signal of a second position of the first selection switch;

[0032] An output control unit, used to control the control flag of the first gating switch through a first mode control signal, and output a gating modulation voltage amplitude;

[0033] A phase generating unit, configured to control a control flag of the second gating switch through a second mode control signal after acquiring an input signal of a first position and an input signal of a second position of the second gating switch according to a preset gain ratio, an integrator and a phase-locked loop, and output a gating phase;

[0034] A signal generating unit is used to generate a pulse control signal of a target voltage source type AC / DC converter according to the gate modulation voltage amplitude and the gate phase, and is used for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid following control mode and a grid forming control mode.

[0035] Preferably, the amplitude generating unit is specifically used for:

[0036] A PI regulator is used to generate a d-axis component of a modulation voltage according to a DC voltage parameter value, wherein the DC voltage parameter value includes a voltage feedback value and a voltage reference value;

[0037] The PI regulator is used to generate a q-axis component of the modulation voltage according to a grid-connected reactive power parameter value, wherein the grid-connected reactive power parameter value includes a reactive feedback value and a reactive reference value;

[0038] Generate a modulation voltage amplitude according to the d-axis component and the q-axis component to obtain a first modulation voltage amplitude;

[0039] The PI regulator is used to generate a second modulation voltage amplitude according to the grid-connected reactive power parameter value and the initial voltage value.

[0040] Preferably, the phase generating unit is specifically used for:

[0041] After processing the DC voltage parameter value with a preset gain ratio, performing signal processing through an integrator to obtain an output phase, and using the output phase as an input signal for the second position of the second selection switch;

[0042] A phase-locked loop is used to detect the grid-connected phase of the grid-connected point voltage, and the grid-connected phase is used as an input signal of the first position of the second selection switch;

[0043] The control flag of the second selection switch is controlled by the second mode control signal to output the selection phase.

[0044] Preferably, the signal generating unit is specifically used for:

[0045] generating a sinusoidal modulation voltage signal according to the gated modulation voltage amplitude and the gated phase;

[0046] Performing pulse width modulation on the sinusoidal modulated voltage signal to generate a pulse control signal for a target voltage source type AC / DC converter;

[0047] Based on the pulse control signal, switching of different preset network type control modes is realized, and the preset network type control modes include a network following control mode and a network building control mode.

[0048] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0049] In the present application, a method for generating a control signal of a voltage source type AC / DC converter is provided, comprising: generating a first modulation voltage amplitude and a second modulation voltage amplitude respectively according to a DC voltage parameter value and a grid-connected reactive power parameter value; using the first modulation voltage amplitude as an input signal of a first position of a first selection switch, and using the second modulation voltage amplitude as an input signal of a second position of the first selection switch; controlling a control flag of the first selection switch by a first mode control signal, and outputting a selection modulation voltage amplitude; after obtaining an input signal of the first position and an input signal of the second position of the second selection switch according to a preset gain ratio, an integrator and a phase-locked loop, controlling the control flag of the second selection switch by a second mode control signal, and outputting a selection phase; generating a pulse control signal of a target voltage source type AC / DC converter according to the selection modulation voltage amplitude and the selection phase, for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid following control mode and a grid forming control mode.

[0050] The voltage source type AC-DC converter control signal generation method provided by the present application realizes the connection between the new energy and the power grid through two gating switches; and based on the DC voltage, the grid-connected reactive power parameter and the signal processor, the signals of the two gating switches are modulated in a targeted manner to generate an adjustable input signal and an output signal, the output signal is the gating modulation voltage amplitude and the gating phase, and the pulse control signal generated based on the output signal can realize the switching of different preset network control modes, that is, the network construction control mode is selected under the condition of weak power grid, and the grid following control mode is selected under the condition of strong power grid, so as to ensure that the target power source type DC converter always maintains strong stability. Therefore, the present application can solve the technical problem that the existing control technology cannot simultaneously meet the stability requirements under the condition of weak power grid and the condition of strong power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic flow chart of a method for generating a control signal for a voltage source AC / DC converter provided in an embodiment of the present application;

[0052] Figure 2 A schematic diagram of the structure of a voltage source type AC / DC converter control signal generating device provided in an embodiment of the present application;

[0053] Figure 3A schematic diagram of the structure of a flexible interconnected distribution network with new energy access provided as the background technology of this application;

[0054] Figure 4 A schematic diagram of the switching control principle of a three-phase voltage source AC / DC converter provided in an embodiment of the present application;

[0055] Figure 5 This is a simulation waveform diagram of the three-phase voltage source AC / DC converter switching from a grid-following control mode to a grid-building control mode provided in the application example of this application. DETAILED DESCRIPTION

[0056] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0057] For easier understanding, see Figure 1 , the present application provides an embodiment of a method for generating a control signal of a voltage source AC / DC converter, comprising:

[0058] Step 101: Generate a first modulation voltage amplitude and a second modulation voltage amplitude according to a DC voltage parameter value and a grid-connected reactive power parameter value.

[0059] Furthermore, step 101 includes:

[0060] A PI regulator is used to generate a d-axis component of a modulation voltage according to a DC voltage parameter value, wherein the DC voltage parameter value includes a voltage feedback value and a voltage reference value;

[0061] A PI regulator is used to generate a q-axis component of a modulation voltage according to a grid-connected reactive power parameter value, wherein the grid-connected reactive power parameter value includes a reactive feedback value and a reactive reference value;

[0062] Generate a modulation voltage amplitude according to the d-axis component and the q-axis component to obtain a first modulation voltage amplitude;

[0063] A PI regulator is used to generate a second modulation voltage amplitude according to a grid-connected reactive power parameter value and an initial voltage value.

[0064] Please note that Figure 4In this embodiment, the converter connected to the interconnected distribution network is a three-phase voltage source AC / DC converter, that is, a DC / AC converter; the AC side of the converter is connected to the flexible interconnected distribution network, and the DC side of the converter is connected in parallel with a capacitor, and the other side of the capacitor is a front-stage converter, which converts the energy of wind power, photovoltaic or energy storage and inputs it into the capacitor.

[0065] See also Figure 4 The pulse signal generation scheme provided in this embodiment is the working mechanism of the three-phase voltage source type AC-DC converter. As can be seen from the figure, the input to the PI regulator is the calculation result of the DC voltage parameter value and the calculation result of the grid-connected reactive power parameter value; specifically, the DC voltage feedback value u dc With voltage reference value u dcref The difference is input into the PI regulator for data analysis, and the reference value i of the d-axis component of the grid-connected current is output. gdref , the reference value i gdref The feedback value i of the d-axis component of the grid-connected current gd After the difference is made, it can be modulated again through a PI regulator to obtain the d-axis component of the modulated voltage, recorded as u td The reactive power feedback value Q in the grid-connected reactive power parameter value g and reactive power reference value Q gref The same is done for the analysis of the input PI regulator after the difference, and the reference value i of the q-axis component of the output grid-connected current is gqref , the reference value i gqref The feedback value i of the grid-connected current q axis gq After the difference is made, it is modulated again through a PI regulator to obtain the q-axis component of the modulated voltage, which is recorded as u tq Next, according to the d-axis component u td and the q-axis component u tq The modulation voltage amplitude can be generated to obtain the first modulation voltage amplitude U t1 .

[0066] Using the same signal modulation method, the second modulation voltage amplitude can be generated by the PI regulator according to the grid-connected reactive power parameter value and the voltage initial value. Specifically, the reactive feedback value Q in the grid-connected reactive power parameter value g and reactive power reference value Q gref The same analysis is performed after the difference is input to the PI regulator. The PI regulator can superimpose the initial value U of the voltage amplitude when outputting the result. t0 , that is, the initial voltage value U t0 , get the modulation voltage amplitude U t2 , that is, the second modulation voltage amplitude U t2 .

[0067] It should be noted that the feedback value i of the d-axis component of the grid-connected current gdand the grid-connected current q-axis feedback value i gq All are three-phase grid-connected power grids abc It is obtained through the rotation coordinate transformation processing; the phase adopted by the rotation coordinate transformation needs to be set according to the actual situation, and the specific details are not limited here.

[0068] Step 102: Use the first modulation voltage amplitude as an input signal of a first position of a first selection switch, and use the second modulation voltage amplitude as an input signal of a second position of the first selection switch.

[0069] according to Figure 4 It can be understood that the first modulation voltage amplitude U t1 That is, the input of the first position 1 of the first selection switch S1. The second modulation voltage amplitude U t2 That is, it is the input of the second position 2 of the first selection switch S1.

[0070] Step 103: Control the control flag of the first selection switch through the first mode control signal, and output the selection modulation voltage amplitude.

[0071] Furthermore, step 103 includes:

[0072] Controlling the control flag of the first selection switch by the first mode control signal to obtain an output voltage amplitude;

[0073] The output voltage amplitude is limited by a preset change rate to obtain a gate modulation voltage amplitude.

[0074] Furthermore, step 103, before that, also includes:

[0075] A preset mode control module is used to obtain a first mode control signal according to the short-circuit ratio of the grid connection point.

[0076] It should be noted that the first mode control signal F1 is information generated according to the preset mode control module, and can enter the control flag of the first gate switch S1 to adjust the output result of the first gate switch S1. The short circuit ratio of the grid connection point is recorded as SCR, which can directly affect the value of the first mode control signal F1; when the short circuit ratio SCR is greater than or equal to the short circuit ratio threshold, the output F1 takes a value of 1, otherwise the output F1 takes a value of 0.

[0077] It is understandable that the short circuit ratio threshold can be set according to actual conditions and is not limited here. The short circuit ratio threshold example given in this embodiment is 2.8. The specific calculation example process is: inject 100Hz and amplitude U in series at the grid connection point h The harmonic voltage of the power grid is measured to be I h , then the short-circuit ratio SCR of the grid-connected point can be expressed as:

[0078]

[0079] Among them, U is the amplitude of the grid-connected point voltage, and S is the actual value of the grid-connected capacitance of the converter.

[0080] It can be understood that the control flag of the gating switch can determine whether the gating switch outputs the input information of the first position 1 or the input information of the second position 2. The control model of the converter can be adjusted according to different output signals to achieve selection of different modes. In this embodiment, when the control flag input of the first gating switch S1 is 1, its output is the input value of the first position 1; when the control flag input of the first gating switch S1 is 0, its output is the input value of the second position 2.

[0081] The preset change rate of this embodiment is expressed by the change rate limiting module. The specific value can be set according to the actual situation and is not limited here. The example given in this embodiment is that the output change rate is less than or equal to 50V / s. The signal is processed by the first selection switch and the output voltage amplitude can be obtained after being limited by the control flag bit. After the amplitude limiting process, the modulation voltage amplitude U t .

[0082] Step 104: after acquiring the input signal of the first position and the input signal of the second position of the second selection switch according to the preset gain ratio, the integrator and the phase-locked loop, the control flag of the second selection switch is controlled by the second mode control signal, and the selection phase is output.

[0083] Furthermore, step 104 includes:

[0084] After processing the DC voltage parameter value with a preset gain ratio, the signal is processed by an integrator to obtain an output phase, and the output phase is used as an input signal for the second position of the second selection switch;

[0085] A phase-locked loop is used to detect the grid-connected phase of the grid-connected point voltage, and the grid-connected phase is used as an input signal for the first position of the second selection switch;

[0086] The control flag of the second selection switch is controlled by the second mode control signal to output the selection phase.

[0087] Please note that Figure 4 , DC voltage parameter values ​​include voltage feedback value u dc With voltage reference value u dcref , before gain processing, calculate the ratio of the DC voltage feedback value to the voltage reference value, and use the preset gain ratio ω Bg The ratio is processed by proportional gain, and the output value after gain processing is input into the integrator to obtain the output phase θ dc , the phase θdc That is, the input signal of the second position 2 of the second selection switch S2. The preset gain ratio value of this embodiment is 100π, and this value can also be set according to actual conditions, and the specific value is not limited. The phase of the grid-connected point voltage is detected by a phase-locked loop, that is, the grid-connected phase θ can be directly obtained. PLL Grid-connected phase θ PLL As the input signal of the first position 1 of the second enable switch S2.

[0088] The control flag of the second selection switch S2 is also determined by the mode control signal. The second mode control signal is the same as the first mode control signal, both are from the mode control module, and both are determined by the short-circuit ratio of the grid connection point. The specific process is not repeated. The second mode control signal acts on the second selection switch S2 to determine the output value and obtain the output selection phase θ. In addition, when the second selection switch S2 is switched from the first position 1 to the second position 2, the initial phase of the integrator is θ P 0 LL .

[0089] It can be understood that when the control flag input of the second selection switch S2 is 1, its output is the input value of the first position 1; when the control flag input of the second selection switch S2 is 0, its output is the input value of the second position 2.

[0090] Step 105, generating a pulse control signal of the target voltage source AC / DC converter according to the gated modulation voltage amplitude and the gated phase, for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid following control mode and a grid forming control mode.

[0091] Further, step 105 includes:

[0092] generating a sinusoidal modulation voltage signal according to a gated modulation voltage amplitude and a gated phase;

[0093] Performing pulse width modulation on the sinusoidal modulated voltage signal to generate a pulse control signal for a target voltage source type AC / DC converter;

[0094] The switching of different preset network type control modes is realized based on the pulse control signal. The preset network type control modes include a network following control mode and a network building control mode.

[0095] It should be noted that according to Figure 4 It can be seen that according to the gate modulation voltage amplitude U t and the gate phase θ can generate a sinusoidal modulated voltage signal u tabc ; Use pulse width modulation module to modulate the sinusoidal voltage signal u tabc By performing pulse width modulation, the pulse control signal S gabcThe pulse control signal acts on the grid-side converter of the target voltage source AC / DC converter to realize the switching between different grid-following control modes and grid-forming control modes to adapt to the system operation under strong grid conditions and weak grid conditions.

[0096] See also Figure 5 In order to verify the effectiveness of the method provided in this embodiment, this application provides a specific simulation application example. Figure 5 The following is a simulation waveform diagram of the converter switching from the grid-following mode to the grid-building mode. At the initial moment, the converter works in the grid-following control mode, the phase-locked loop control bandwidth is 5Hz, the short-circuit ratio of the grid-connected point is 2.5, and the converter can operate stably; at 9 seconds, the phase-locked loop control bandwidth is 20Hz, and the DC voltage, output current, and output active power of the converter oscillate and diverge, and the converter operation is unstable. At 9.6 seconds, the converter switches from the grid-following mode to the grid-building mode, and the DC voltage, output current, and output active power of the converter gradually return to normal, and the converter operates stably.

[0097] According to the simulation waveform Figure 5 It can be seen that the converter control signal generation method for a flexible interconnected distribution network provided in the present application enables the converter with DC voltage as the control target to automatically switch between the grid-forming control mode and the grid-following control mode according to the grid strength, that is, switching to the grid-following control mode under strong grid conditions and switching to the grid-forming control mode under weak grid conditions, which makes up for the defect that the existing mode switching control system is only for converters with active power as the control target, thereby ensuring that the converter with DC voltage as the control target has strong stability under both strong and weak grids.

[0098] The voltage source type AC-DC converter control signal generation method provided in the embodiment of the present application realizes the connection between the new energy and the power grid through two gating switches; and the signals of the two gating switches are modulated in a targeted manner based on the DC voltage, the grid-connected reactive power parameter and the signal processor, respectively, to generate an adjustable input signal and an output signal, the output signal is the gating modulation voltage amplitude and the gating phase, and the pulse control signal generated based on the output signal can realize the switching of different preset network control modes, that is, the network construction control mode is selected under the condition of weak power grid, and the grid following control mode is selected under the condition of strong power grid, so as to ensure that the target power source type DC converter always maintains a strong stability. Therefore, the embodiment of the present application can solve the technical problem that the existing control technology cannot simultaneously meet the stability requirements under the condition of weak power grid and the condition of strong power grid.

[0099] For easier understanding, see Figure 2 The present application provides an embodiment of a voltage source type AC / DC converter control signal generating device, comprising:

[0100] An amplitude generating unit 201 is used to generate a first modulation voltage amplitude and a second modulation voltage amplitude according to a DC voltage parameter value and a grid-connected reactive power parameter value;

[0101] A signal definition unit 202, configured to use the first modulation voltage amplitude as an input signal for a first position of a first selection switch, and the second modulation voltage amplitude as an input signal for a second position of the first selection switch;

[0102] An output control unit 203, used to control the control flag of the first gating switch through the first mode control signal, and output the gating modulation voltage amplitude;

[0103] The phase generating unit 204 is used to control the control flag of the second gating switch through the second mode control signal after acquiring the input signal of the first position and the input signal of the second position of the second gating switch according to the preset gain ratio, the integrator and the phase-locked loop, and output the gating phase;

[0104] The signal generating unit 205 is used to generate a pulse control signal of the target voltage source AC / DC converter according to the gated modulation voltage amplitude and the gated phase, and is used for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid following control mode and a grid forming control mode.

[0105] Further, the amplitude generating unit 201 is specifically used for:

[0106] A PI regulator is used to generate a d-axis component of a modulation voltage according to a DC voltage parameter value, wherein the DC voltage parameter value includes a voltage feedback value and a voltage reference value;

[0107] A PI regulator is used to generate a q-axis component of a modulation voltage according to a grid-connected reactive power parameter value, wherein the grid-connected reactive power parameter value includes a reactive feedback value and a reactive reference value;

[0108] Generate a modulation voltage amplitude according to the d-axis component and the q-axis component to obtain a first modulation voltage amplitude;

[0109] A PI regulator is used to generate a second modulation voltage amplitude according to a grid-connected reactive power parameter value and an initial voltage value.

[0110] Further, the phase generating unit 204 is specifically configured to:

[0111] After processing the DC voltage parameter value with a preset gain ratio, the signal is processed by an integrator to obtain an output phase, and the output phase is used as an input signal for the second position of the second selection switch;

[0112] A phase-locked loop is used to detect the grid-connected phase of the grid-connected point voltage, and the grid-connected phase is used as an input signal for the first position of the second selection switch;

[0113] The control flag of the second selection switch is controlled by the second mode control signal to output the selection phase.

[0114] Further, the signal generating unit 205 is specifically configured to:

[0115] generating a sinusoidal modulation voltage signal according to a gated modulation voltage amplitude and a gated phase;

[0116] Performing pulse width modulation on the sinusoidal modulated voltage signal to generate a pulse control signal for a target voltage source type AC / DC converter;

[0117] The switching of different preset network type control modes is realized based on the pulse control signal. The preset network type control modes include a network following control mode and a network building control mode.

[0118] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0119] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0120] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0121] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for executing all or part of the steps of the method described in each embodiment of the present application through a computer device (which can be a personal computer, a server, or a network device, etc.). The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[0122] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for generating a control signal of a voltage source AC / DC converter, characterized in that: include: The first modulation voltage amplitude and the second modulation voltage amplitude are generated respectively according to the DC voltage parameter value and the grid-connected reactive power parameter value. The specific generation process is as follows: A PI regulator is used to generate a d-axis component of a modulation voltage according to a DC voltage parameter value, wherein the DC voltage parameter value includes a voltage feedback value and a voltage reference value; The PI regulator is used to generate a q-axis component of the modulation voltage according to a grid-connected reactive power parameter value, wherein the grid-connected reactive power parameter value includes a reactive feedback value and a reactive reference value; Generate a modulation voltage amplitude according to the d-axis component and the q-axis component to obtain a first modulation voltage amplitude; Using the PI regulator to generate a second modulation voltage amplitude according to the grid-connected reactive power parameter value and the voltage initial value; Using the first modulation voltage amplitude as an input signal of a first position of a first gate switch, and using the second modulation voltage amplitude as an input signal of a second position of the first gate switch; Controlling the control flag of the first gating switch through a first mode control signal, and outputting a gating modulation voltage amplitude; After obtaining the input signal of the first position and the input signal of the second position of the second selection switch according to the preset gain ratio, the integrator and the phase-locked loop, the control flag of the second selection switch is controlled by the second mode control signal, and the selection phase is output. The specific process is: After processing the DC voltage parameter value with a preset gain ratio, performing signal processing through an integrator to obtain an output phase, and using the output phase as an input signal for the second position of the second selection switch; A phase-locked loop is used to detect the grid-connected phase of the grid-connected point voltage, and the grid-connected phase is used as an input signal of the first position of the second selection switch; Control the control flag of the second gating switch by a second mode control signal to output a gating phase; A pulse control signal of a target voltage source AC / DC converter is generated according to the gated modulation voltage amplitude and the gated phase, and is used for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid following control mode and a grid forming control mode.

2. The method for generating a control signal for a voltage source AC / DC converter according to claim 1, wherein: The control flag of the first gating switch is controlled by the first mode control signal, and the gating modulation voltage amplitude is outputted, including: Controlling the control flag of the first selection switch by a first mode control signal to obtain an output voltage amplitude; The output voltage amplitude is limited by a preset change rate to obtain a gate modulation voltage amplitude.

3. The method for generating a control signal for a voltage source AC / DC converter according to claim 2, wherein: The control flag of the first gate switch is controlled by the first mode control signal to obtain the output voltage amplitude, and the method further includes: A preset mode control module is used to obtain a first mode control signal according to the short-circuit ratio of the grid connection point.

4. The method for generating a control signal for a voltage source AC / DC converter according to claim 1, wherein: The pulse control signal of the target voltage source type AC / DC converter is generated according to the gated modulation voltage amplitude and the gated phase, and is used for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid-following control mode and a grid-forming control mode, including: generating a sinusoidal modulation voltage signal according to the gated modulation voltage amplitude and the gated phase; Performing pulse width modulation on the sinusoidal modulated voltage signal to generate a pulse control signal for a target voltage source type AC / DC converter; Based on the pulse control signal, switching of different preset network type control modes is realized, and the preset network type control modes include a network following control mode and a network building control mode.

5. A voltage source type AC / DC converter control signal generating device, characterized in that: include: An amplitude generating unit is used to generate a first modulation voltage amplitude and a second modulation voltage amplitude according to a DC voltage parameter value and a grid-connected reactive power parameter value, respectively. The amplitude generating unit is specifically used to: A PI regulator is used to generate a d-axis component of a modulation voltage according to a DC voltage parameter value, wherein the DC voltage parameter value includes a voltage feedback value and a voltage reference value; The PI regulator is used to generate a q-axis component of the modulation voltage according to a grid-connected reactive power parameter value, wherein the grid-connected reactive power parameter value includes a reactive feedback value and a reactive reference value; Generate a modulation voltage amplitude according to the d-axis component and the q-axis component to obtain a first modulation voltage amplitude; Using the PI regulator to generate a second modulation voltage amplitude according to the grid-connected reactive power parameter value and the voltage initial value; a signal definition unit, configured to use the first modulation voltage amplitude as an input signal of a first position of a first selection switch, and the second modulation voltage amplitude as an input signal of a second position of the first selection switch; An output control unit, used to control the control flag of the first gating switch through a first mode control signal, and output a gating modulation voltage amplitude; A phase generating unit is used to obtain the input signal of the first position and the input signal of the second position of the second gating switch according to the preset gain ratio, the integrator and the phase-locked loop, control the control flag of the second gating switch through the second mode control signal, and output the gating phase, wherein the phase generating unit is specifically used to: After processing the DC voltage parameter value with a preset gain ratio, performing signal processing through an integrator to obtain an output phase, and using the output phase as an input signal for the second position of the second selection switch; A phase-locked loop is used to detect the grid-connected phase of the grid-connected point voltage, and the grid-connected phase is used as an input signal of the first position of the second selection switch; Control the control flag of the second gating switch by a second mode control signal to output a gating phase; A signal generating unit is used to generate a pulse control signal of a target voltage source type AC / DC converter according to the gate modulation voltage amplitude and the gate phase, and is used for switching between different preset grid type control modes, wherein the preset grid type control modes include a grid following control mode and a grid forming control mode.

6. The voltage source type AC / DC converter control signal generating device according to claim 5, characterized in that: The signal generating unit is specifically used for: generating a sinusoidal modulation voltage signal according to the gated modulation voltage amplitude and the gated phase; Performing pulse width modulation on the sinusoidal modulated voltage signal to generate a pulse control signal for a target voltage source type AC / DC converter; Based on the pulse control signal, switching of different preset network type control modes is realized, and the preset network type control modes include a network following control mode and a network building control mode.

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