Reactive current command generation method and related device, reactive current control method

Abstract

This application pertains to a power grid control method. Addressing the technical problem that current methods for generating negative-sequence reactive current commands directly affect the magnitude and phase of the reactive current output by the energy storage converter during asymmetrical low-voltage ride-through, this application provides a reactive current command generation method and related devices, as well as a reactive current control method. First, the grid voltage angular frequency is obtained. Then, the three-phase grid voltage is transformed using coordinates to obtain the positive-sequence active component, positive-sequence reactive component, negative-sequence active component, and negative-sequence reactive component. Next, the corresponding DC components are obtained. Through accurate calculation, the corresponding positive-sequence reactive current axis component command values, negative-sequence reactive current axis component command values, and negative-sequence reactive current axis component command values ​​are obtained. The method of this application has a simple calculation process, low computational load, and is easy to implement and promote. Furthermore, it requires minimal digital storage resources and can fully meet the reactive current output requirements.

Description

Technical Field

[0001] The present application relates to a power grid control method, and specifically to a reactive current instruction generation method and related devices, and a reactive current control method. Background Art

[0002] For energy storage converters, during the asymmetric low voltage ride-through process, it is necessary to output positive sequence reactive current to support positive sequence voltage recovery and absorb negative sequence reactive current from the grid to suppress the increase of negative sequence voltage. Among them, the positive sequence reactive current command can be phase-locked by the grid voltage, and then Positive sequence coordinate transformation, The axis represents the active component, The axis represents the reactive component. The drop depth of the shaft positive sequence voltage can be obtained according to the national standard requirements. Axis positive sequence reactive current command. However, for negative sequence reactive current command, the existing technology usually uses Negative sequence transformation, we get The drop depth of the shaft negative sequence voltage produces However, for this method of generating negative-sequence reactive current instructions, the angle obtained by the currently commonly used grid phase locking is the positive-sequence grid voltage angle. In the process of asymmetric low voltage ride-through, only under the special condition that the negative-sequence grid voltage starting angle is consistent with the positive-sequence grid voltage starting angle, can the method of generating negative-sequence reactive current instructions generate The axis negative sequence reactive current command is accurate. If it is inconsistent, the generated The axis negative-sequence reactive current command will have a large deviation, thereby affecting the negative-sequence reactive power output by the energy storage inverter.

[0003] The starting angle of the negative sequence grid voltage generated during the actual asymmetric low voltage ride-through process is not fixed and is related to the moment of the asymmetric low voltage ride-through. The axis negative-sequence reactive current command has shortcomings, which will directly affect the magnitude and phase of the reactive current output by the energy storage converter during the asymmetric low voltage ride-through process. Summary of the invention

[0004] This application is generated for the current The method of axis negative sequence reactive current instruction will directly affect the technical problem of the size and phase of the reactive current output by the energy storage converter during the asymmetric low voltage ride-through process. A reactive current instruction generation method and related devices, and a reactive current control method are provided.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, the present application proposes a method for generating a reactive current instruction, comprising:

[0007] Obtain grid voltage angular frequency;

[0008] Combined with the grid voltage angular frequency, the three-phase grid voltage is positive sequenced Coordinate transformation is used to obtain positive sequence active component and positive sequence reactive component; and the three-phase grid voltage is negative sequenced by combining the grid voltage angular frequency. Coordinate transformation to obtain negative sequence active component and negative sequence reactive component;

[0009] The DC components of the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component are obtained respectively;

[0010] According to the DC component of the positive sequence active component, the positive sequence reactive current required to be generated during asymmetric low voltage ride through is calculated Axis component command value; Calculate the negative sequence reactive current required to be generated during asymmetric low voltage ride-through based on the DC component of the negative sequence active component and the negative sequence reactive component axis component command value and negative-sequence reactive current d-axis component command value.

[0011] Further, the obtaining of grid voltage angular frequency includes:

[0012] Positive sequence of three-phase grid voltage Coordinate transformation to obtain the positive sequence reactive component;

[0013] The second-order band-stop filter with twice the grid frequency is used to filter out the twice-frequency AC component in the positive-sequence reactive component, and obtain the DC component of the positive-sequence reactive component;

[0014] Enter the difference between the DC component of the positive sequence reactive component and the DC component setpoint of the positive sequence reactive component into Regulator, get angular velocity deviation ;

[0015] Deflect the angular velocity Rated angular velocity of the energy storage converter Subtract and get the actual angular velocity ;

[0016] The actual angular velocity Perform integration processing to obtain the grid voltage angular frequency .

[0017] Furthermore, the three-phase grid voltage is positively sequenced by combining the grid voltage angular frequency. Coordinate transformation is used to obtain the positive sequence active component and positive sequence reactive component, including:

[0018]

[0019] in, is the voltage of the three-phase grid Phase voltage, is the voltage of the three-phase grid Phase voltage, is the voltage of the three-phase grid Phase voltage, is the positive sequence active component, is the positive sequence reactive component;

[0020] The three-phase grid voltage is negatively sequenced by combining the grid voltage angular frequency. Coordinate transformation, the negative sequence active component and negative sequence reactive component are obtained, including:

[0021]

[0022] in, is the negative sequence active component, It is the negative sequence reactive component.

[0023] Further, the steps of respectively obtaining the DC components of the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component include:

[0024] The second-order band-stop filter with twice the grid frequency is used to filter out the twice-frequency AC components in the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component, respectively, and the DC components of the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component are obtained accordingly.

[0025] Furthermore, the positive sequence reactive current required to be generated during asymmetric low voltage ride through is calculated based on the DC component of the positive sequence active component. Axis component command values, including:

[0026]

[0027] in, The positive sequence active current required to be generated during asymmetric low voltage ride-through Axis component, is the dynamic positive sequence reactive current proportional coefficient of the energy storage converter, is the DC component of the positive sequence active component, is the rated voltage of the grid, is the grid rated current, is the amplitude of the positive sequence component.

[0028] Furthermore, the negative sequence reactive current required to be generated during asymmetric low voltage ride through is calculated based on the DC component of the negative sequence active component and the negative sequence reactive component. Axis component command value and negative sequence reactive current Axis component command values, including:

[0029]

[0030] in, Negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component, Negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component, is the dynamic negative sequence reactive current proportional coefficient of the energy storage converter, is the DC component of the negative sequence reactive component, is the DC component of the negative sequence active component.

[0031] In a second aspect, the present application proposes a reactive current control method, comprising:

[0032] The above reactive current command generation method is used to obtain the positive sequence reactive current Axis component command value, negative sequence reactive current Axis component command value and negative sequence reactive current Axis component command value;

[0033] According to the positive sequence reactive current Axis component command value, negative sequence reactive current Axis component command value and negative sequence reactive current The axis component command value controls the energy storage converter during the asymmetric low voltage ride-through process.

[0034] Furthermore, the controlling of the energy storage converter during the asymmetric low voltage ride-through process includes:

[0035] The positive sequence active current Axis set value Positive sequence active current Axis feedback value The difference is input to regulator, obtain the first output; and convert the positive sequence active current Axis feedback value Input to Axis and Shaft decoupler , and obtain the second output;

[0036] The positive sequence reactive current Axis component command value Positive sequence reactive current Axis feedback value The difference is input to regulator, and obtain the third output; and convert the positive sequence reactive current Axis feedback value Input to Axis and Shaft decoupler , and obtain the fourth output;

[0037] The negative sequence reactive current Axis component command value and negative sequence active current Axis feedback value The difference is input to regulator, and obtain the fifth output; and convert the negative sequence active current Axis feedback value Input to Axis and Shaft decoupler , and obtain the sixth output;

[0038] The negative sequence reactive current Axis component command value Negative sequence reactive current Axis feedback value The difference is input to regulator, and obtain the seventh output; and convert the negative sequence reactive current Axis feedback value Input to Axis and Shaft decoupler , and obtain the eighth output;

[0039] The first output and the positive sequence active component Sum and subtract from the fourth output to obtain the ninth output;

[0040] The second output, the third output and the positive sequence active component Sum and get the tenth output;

[0041] The fifth output, the eighth output and the negative sequence active component Sum and get the eleventh output;

[0042] The seventh output and negative sequence reactive component Sum and subtract from the sixth output to obtain the twelfth output;

[0043] Combined with the grid voltage angular frequency The negative value of Coordinate transformation, get the thirteenth output; and combined with the grid voltage angular frequency The negative value of Coordinate transformation to obtain the fourteenth output;

[0044] Add the thirteenth output and the fourteenth output to obtain the fifteenth output;

[0045] The fifteenth output is pulse-width modulated to obtain a control signal for controlling the energy storage converter.

[0046] In a third aspect, the present application provides an electronic device, comprising:

[0047] Memory for storing computer programs;

[0048] A processor is used to implement the steps of the above-mentioned reactive current instruction generation method when executing the computer program.

[0049] In a fourth aspect, the present application proposes a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned reactive current instruction generation method are implemented.

[0050] Compared with the prior art, this application has the following beneficial effects:

[0051] The present application proposes a method for generating reactive current instructions. First, the grid voltage angular frequency is obtained, and the coordinate transformation of the three-phase grid voltage is performed to obtain the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component, and the negative-sequence reactive component. Then, the corresponding DC components are obtained respectively, and the corresponding positive-sequence reactive current is obtained by accurate calculation. Axis component command value, negative sequence reactive current Axis component command value and negative sequence reactive current Axis component command value. The method of the present application has a simple calculation process, a small amount of calculation, and is easy to implement and promote. It also occupies small digital storage resources and has a low implementation cost. In addition, the method of the present application can accurately calculate the positive sequence reactive current command and the negative sequence reactive current command in various low voltage crossing conditions, and can fully meet the reactive current output requirements.

[0052] The present application also proposes a reactive current control method, an electronic device and a computer storage medium, which have all the advantages of the reactive current instruction generation method mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0054] Figure 1This is a schematic diagram of a first flow chart of a reactive current command generation method of the present application;

[0055] Figure 2 A second flow chart of the reactive current command generation method of the present application;

[0056] Figure 3 A schematic diagram of the principle of obtaining the grid voltage angular frequency in an embodiment of the present application;

[0057] Figure 4 A schematic diagram of the principle of obtaining a DC component in an embodiment of the present application;

[0058] Figure 5 A schematic diagram of a principle for controlling an energy storage converter in an embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, 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 part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0060] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0061] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0062] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invented product is usually placed when used. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0063] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0064] In the description of the embodiments of the present application, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0065] Energy storage converter is a kind of power electronic device, which is mainly used to connect energy storage device and power grid or load to realize bidirectional conversion and control of electric energy. Energy storage converter receives DC power from energy storage system or power grid, converts DC power into high-frequency AC power through internal DC / AC bidirectional converter, and adjusts the on and off time of internal switch tube according to the instruction of control unit, controls the output AC voltage, frequency and power and other parameters, and supplies the converted high-frequency AC power to AC load, or supplies other equipment after voltage conversion through transformer and other equipment.

[0066] Low voltage ride-through means that when the grid voltage drops, power generation grid-connected equipment such as photovoltaic inverters, wind power converters, and energy storage converters can maintain grid-connected operation and have a certain dynamic reactive power to support grid voltage recovery. During asymmetric low voltage ride-through, the grid voltage not only decreases in amplitude, but also may become asymmetric in three-phase voltage. At this time, the energy storage converter needs to adopt a specific control strategy to deal with it. When the grid voltage drops asymmetrically, the energy storage converter needs to detect and decompose the positive sequence component in the voltage. In response to the drop in positive sequence voltage, the energy storage converter will output an appropriate amount of positive sequence reactive current to provide the magnetic field energy required by the grid and help the positive sequence voltage to recover. The output of positive sequence reactive current can be determined according to the drop depth of the grid voltage and the capacity of the energy storage converter. In an asymmetric fault, a negative-sequence voltage component will be generated in the power grid, which may cause the imbalance of the power grid voltage to increase. In order to suppress the increase of negative-sequence voltage, the energy storage converter needs to absorb an appropriate amount of negative-sequence reactive current from the power grid. Absorbing negative-sequence reactive current helps to reduce the negative-sequence component in the power grid, thereby reducing voltage imbalance and stabilizing the power grid voltage.

[0067] Among them, when the negative-sequence reactive current command is generated, the grid phase-locked loop is usually used to obtain the angle of the positive-sequence grid voltage, and the negative-sequence reactive current command is generated based on this. However, the effectiveness of this method is highly dependent on whether the starting angle of the negative-sequence grid voltage is consistent with the starting angle of the positive-sequence grid voltage. In practical applications, since the starting angle of the negative-sequence voltage is not fixed and is related to the specific moment of LVRT (Low Voltage Ride Through). Therefore, this method often cannot guarantee the accuracy of the negative-sequence reactive current command.

[0068] Based on the above situation, the present application proposes a reactive current instruction generation method and related devices, and a reactive current control method. The present application is described in detail below in conjunction with embodiments and drawings.

[0069] like Figure 1 As shown, it is a first flow chart of a method for generating a negative sequence reactive current command of the present application, which may include:

[0070] S101, obtaining grid voltage angular frequency.

[0071] It should be noted that in a three-phase power grid, the waveform of the phase voltage is usually a sine wave, and there is a certain phase difference between the three phases, usually 120 degrees. In a three-phase power grid, the angular frequency is usually a constant value, which represents the number of radians that the voltage waveform changes per second. The angular frequency is very important for the stable operation of the power grid and the normal operation of power equipment. The angular frequency can be calculated by measuring the voltage waveform of any phase and determining the period. In practical applications, software phase locking can be used to track the phase and frequency of the voltage for accurate measurement and control. Software phase locking can be used to accurately track and measure the phase and frequency of the three-phase power grid voltage. By selecting appropriate measurement methods and algorithms, high-precision angular frequency measurement can be achieved, providing important data support for the monitoring and control of the power grid.

[0072] S102, combining the grid voltage angular frequency, performs positive sequence on the three-phase grid voltage Coordinate transformation is used to obtain positive sequence active component and positive sequence reactive component; and the three-phase grid voltage is negative sequenced by combining the grid voltage angular frequency. Coordinate transformation is performed to obtain the negative-sequence active component and negative-sequence reactive component.

[0073] It should be noted that the positive sequence Coordinate transformation is to transform the positive sequence component in the three-phase stationary coordinate system into the two-phase rotating coordinate system, and consider the zero sequence component and the negative sequence component. Coordinate transformation is to convert the negative sequence component in the three-phase stationary coordinate system to the two-phase rotating coordinate system, and consider the zero sequence component. This transformation helps to simplify the design of control strategies and analyze asymmetric faults in power systems. In practical applications, the transformation from the three-phase stationary coordinate system to the two-phase rotating coordinate system can be achieved through a transformation matrix.

[0074] S103, respectively obtaining the DC components of the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component, and the negative-sequence reactive component.

[0075] In practical applications, in order to obtain the DC component, the converted positive-sequence active component, positive-sequence reactive component, negative-sequence active component and negative-sequence reactive component are subjected to band-stop filtering to remove the double frequency AC component and retain only the DC component.

[0076] S104, based on the DC component of the positive-sequence active component, calculate the positive-sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component command value; Calculate the negative sequence reactive current required to be generated during asymmetric low voltage ride-through based on the DC component of the negative sequence active component and the negative sequence reactive component Axis component command value and negative sequence reactive current Axis component command value.

[0077] like Figure 2 As shown, it is a second flow chart of a method for generating a negative sequence reactive current command of the present application, which may include:

[0078] S201, perform software phase locking on the three-phase grid voltage to obtain the grid voltage angular frequency ;

[0079] like Figure 3 As shown, it is a schematic diagram of the principle of obtaining the grid voltage angular frequency. Figure 3 middle, , and Respectively Phase voltage, Phase voltage and Phase voltage, through Coordinate transformation, get the positive sequence active component and positive sequence reactive component , and then pass through a band-stop filter with a center frequency twice the grid frequency to obtain the DC component of the positive sequence reactive component , the DC component of the positive sequence reactive component The difference between the DC component set value of the positive sequence reactive component is input to Regulator, get angular velocity deviation , and then make the angular velocity deflection Rated angular velocity of the energy storage converter Subtract and get the actual angular velocity , for the actual angular velocity Perform integration processing to obtain the grid voltage angular frequency .

[0080] S202, positive sequence of three-phase grid voltage Coordinate transformation, get the positive sequence active component and positive sequence reactive component ; and negative sequence the three-phase grid voltage Coordinate transformation, get the negative sequence active component and negative sequence reactive components .

[0081] When the three-phase grid voltage drops asymmetrically, the three-phase grid voltage is composed of positive sequence component, negative sequence component and zero sequence component. Among them, the positive sequence component is the component with the same phase sequence as the power supply, also known as the sequential component; the negative sequence component is the component opposite to the power supply phase sequence, also known as the reverse sequence component, which will appear in the case of asymmetrical faults or asymmetrical loads; the zero sequence component is a set of components with equal effective values ​​of three vectors and a phase difference of 360° between each other. The positive sequence component, negative sequence component and zero sequence component respectively represent the symmetrical component in the power system, the reverse sequence component generated by asymmetrical faults or loads, and the same direction component generated by ground faults or unbalanced loads.

[0082] When the three-phase grid voltage drops asymmetrically, the instantaneous value of the three-phase grid voltage can be expressed by formula (1):

[0083] (1)

[0084] in, is the amplitude of the positive sequence component, is the amplitude of the negative sequence component, is the amplitude of the zero-sequence component, for Phase voltage, for Phase voltage, for Phase voltage, is the grid voltage angular velocity, For time, is the phase of the negative sequence component of the grid voltage compared to the positive sequence component, is the phase of the zero sequence component compared to the positive sequence component.

[0085] Positive sequence of three-phase grid voltage Coordinate transformation, get the positive sequence active component (correspond axis) and positive sequence reactive components (correspond axis). Among them, the positive sequence active component Contains DC component and AC component Similarly, the positive sequence reactive component Also includes DC component and AC component The specific expression is shown in formula (2):

[0086] (2)

[0087] in, It is the phase of the negative sequence component of the grid voltage compared to the positive sequence component.

[0088] And negative sequence the three-phase grid voltage Coordinate transformation, get the negative sequence active component (correspond axis) and negative sequence reactive components (correspond axis), where Contains DC component and AC component , Also includes DC component and AC component , the specific expression is shown in formula (3):

[0089] (3)

[0090] S203, the positive sequence active component obtained in step S202 , positive sequence reactive component , negative sequence active component and negative sequence reactive components , through a second-order band-stop filter whose center frequency is twice the grid frequency, the double frequency AC component is filtered out to obtain the corresponding DC component , DC component , DC component and DC component .

[0091] like Figure 4 As shown in the figure, it is a schematic diagram of the principle of obtaining the DC component. According to the above formulas (2) and (3), the DC component can be , DC component , DC component and DC component Use formula (4) to express:

[0092] (4)

[0093] S204, calculate the positive sequence reactive current required for asymmetric low voltage ride through Axis component command value, negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component command value and negative sequence reactive current Axis component command value.

[0094] Assume that the rated voltage of the grid is , the rated current of the grid is , positive sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component command value for:

[0095] (5)

[0096] in, It is the dynamic positive sequence reactive current proportional coefficient of the energy storage converter.

[0097] For positive sequence reactive current Axis component command value conduct After coordinate transformation, we can get

[0098] The positive sequence reactive current command in the coordinate system is shown in formula (6):

[0099] (6)

[0100] in, is the positive sequence reactive current command Phase instruction, is the positive sequence reactive current command Phase instruction, is the positive sequence reactive current command Phase instruction.

[0101] By comparing the phase of the positive sequence grid voltage, we can intuitively see that the calculated Positive sequence reactive current command in the coordinate system , , , ahead of the positive sequence grid voltage phase , which is a pure capacitive reactive current instruction. By controlling the output current of the energy storage converter to follow the positive-sequence reactive current instruction, the purpose of supporting the positive-sequence voltage recovery can be achieved.

[0102] The negative sequence active current generated during asymmetric low voltage ride-through and the DC component of the negative sequence active component and the DC component of the negative sequence reactive component All are related:

[0103] (7)

[0104] in, Negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component, Negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component, It is the dynamic positive sequence reactive current proportional coefficient of the energy storage converter.

[0105] Compared with the positive sequence reactive current command, the negative sequence reactive current command is significantly different. The negative sequence reactive current required to be generated during asymmetric low voltage ride through Axis Component and the negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis Component conduct After transformation, we get The negative sequence reactive current command in the coordinate system is shown in formula (8):

[0106] (8)

[0107] in, The negative sequence reactive current command Phase instruction, The negative sequence reactive current command Phase instruction, The negative sequence reactive current command Phase instruction.

[0108] By comparing the phase of the negative sequence grid voltage, it can be seen intuitively that the calculated The negative sequence reactive current command in the coordinate system lags behind the negative sequence grid voltage phase , which is a purely inductive reactive current instruction. By controlling the output current of the energy storage converter to follow the negative-sequence reactive current instruction, the purpose of suppressing the increase of negative-sequence voltage can be achieved.

[0109] Based on the above reactive current command generation method, the present application also proposes a reactive current control method, which may include:

[0110] (1) Using the above reactive current command generation method, the positive sequence reactive current is obtained Axis component command value, negative sequence reactive current Axis component command value and negative sequence reactive current Axis component command value.

[0111] (2) According to the positive sequence reactive current Axis component command value, negative sequence reactive current Axis component command value and negative sequence reactive current The axis component command value controls the energy storage converter during the asymmetric low voltage ride-through process.

[0112] like Figure 5 As shown, it is a schematic diagram of a principle for controlling an energy storage converter, which may include:

[0113] (1) The positive sequence active current Axis set value Positive sequence active current Axis feedback value The difference is input to regulator, obtain the first output; and convert the positive sequence active current Axis feedback value Input to Axis and Shaft decoupler , and obtain the second output;

[0114] (2) The positive sequence reactive current Axis component command value Positive sequence reactive current Axis feedback value The difference is input to regulator, and obtain the third output; and convert the positive sequence reactive current Axis feedback value Input to Axis and Shaft decoupler , and obtain the fourth output;

[0115] (3) Negative sequence reactive current Axis component command value and negative sequence active current Axis feedback value The difference is input to regulator, and obtain the fifth output; and convert the negative sequence active current Axis feedback value Input to Axis and Shaft decoupler , and obtain the sixth output;

[0116] (4) Negative sequence reactive current Axis component command value Negative sequence reactive current Axis feedback value The difference is input to regulator, and obtain the seventh output; and convert the negative sequence reactive current Axis feedback value Input to Axis and Shaft decoupler , and obtain the eighth output;

[0117] (5) The first output and positive sequence active component Sum and subtract from the fourth output to obtain the ninth output;

[0118] (6) The second output, the third output and the positive sequence active component Sum and get the tenth output;

[0119] (7) The fifth output, the eighth output and the negative sequence active component Sum and get the eleventh output;

[0120] (8) The seventh output and negative sequence reactive component Sum and subtract from the sixth output to obtain the twelfth output;

[0121] (9) Combined with the grid voltage angular frequency The negative value of Coordinate transformation, get the thirteenth output; and combined with the grid voltage angular frequency The negative value of Coordinate transformation to obtain the fourteenth output;

[0122] (10) Add the thirteenth output and the fourteenth output to obtain the fifteenth output;

[0123] (11) Pulse width modulation is performed on the fifteenth output to obtain a control signal for controlling the energy storage converter.

[0124] During the low voltage ride-through process of the energy storage converter, the above method is used to finally drive the output of the energy storage converter to follow the positive sequence reactive current and negative sequence reactive current of the corresponding instructions.

[0125] An electronic device provided in an embodiment of the present application includes a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps of the reactive current instruction generation method described in any of the above embodiments are implemented.

[0126] Another electronic device provided in the embodiment of the present application may also include: an input port connected to the processor, used to transmit multimodal data collected by an external acquisition device to the processor; and a display unit connected to the processor, used to display the processing results of the processor to the outside world; a communication module connected to the processor, used to realize the communication between the electronic device and the outside world. The display unit can be a display panel, a laser scanning display, etc.; the communication mode adopted by the communication module includes but is not limited to mobile high-definition link technology (HML), universal serial bus (USB), high-definition multimedia interface (HDMI), wireless connection (including wireless fidelity technology (WiFi), Bluetooth communication technology, low-power Bluetooth communication technology, and communication technology based on IEEE802.11s).

[0127] An embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the steps of the reactive current instruction generating method described in any of the above embodiments are implemented.

[0128] The computer-readable storage medium involved in the present application includes random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the technical field.

[0129] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for generating a reactive current instruction, characterized in that: include: Obtain grid voltage angular frequency; Combined with the grid voltage angular frequency, the three-phase grid voltage is positive sequenced Coordinate transformation to obtain positive sequence active component and positive sequence reactive component; Combined with the grid voltage angular frequency, the three-phase grid voltage is negative sequenced Coordinate transformation to obtain negative sequence active component and negative sequence reactive component; The DC components of the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component are obtained respectively; According to the DC component of the positive sequence active component, the positive sequence reactive current required to be generated during asymmetric low voltage ride through is calculated Axis component command value: in, The positive sequence active current required to be generated during asymmetric low voltage ride-through Axis component, is the dynamic positive sequence reactive current proportional coefficient of the energy storage converter, is the DC component of the positive sequence active component, is the rated voltage of the grid, is the grid rated current, is the amplitude of the positive sequence component; According to the DC components of the negative-sequence active component and the negative-sequence reactive component, the negative-sequence reactive current required for asymmetric low voltage ride-through is calculated. Axis component command value and negative sequence reactive current d-axis component command value: in, Negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component, Negative sequence reactive current required to be generated during asymmetric low voltage ride-through Axis component, is the dynamic negative sequence reactive current proportional coefficient of the energy storage converter, is the DC component of the negative sequence reactive component, is the DC component of the negative sequence active component.

2. The method for generating reactive current command according to claim 1, characterized in that: The obtaining of grid voltage angular frequency comprises: Positive sequence of three-phase grid voltage Coordinate transformation to obtain the positive sequence reactive component; The second-order band-stop filter with twice the grid frequency is used to filter out the twice-frequency AC component in the positive-sequence reactive component, and obtain the DC component of the positive-sequence reactive component; Enter the difference between the DC component of the positive sequence reactive component and the DC component setpoint of the positive sequence reactive component into Regulator, get angular velocity deviation ; Deflect the angular velocity Rated angular velocity of the energy storage converter Subtract and get the actual angular velocity ; The actual angular velocity Perform integration processing to obtain the grid voltage angular frequency .

3. The method for generating reactive current command according to claim 2, characterized in that: The three-phase grid voltage is positively sequenced by combining the grid voltage angular frequency. Coordinate transformation is used to obtain the positive sequence active component and positive sequence reactive component, including: in, is the voltage of the three-phase grid Phase voltage, is the voltage of the three-phase grid Phase voltage, is the voltage of the three-phase grid Phase voltage, is the positive sequence active component, is the positive sequence reactive component; The three-phase grid voltage is negatively sequenced by combining the grid voltage angular frequency. Coordinate transformation, the negative sequence active component and negative sequence reactive component are obtained, including: in, is the negative sequence active component, It is the negative sequence reactive component.

4. The method for generating reactive current command according to claim 3, characterized in that: The method of respectively obtaining the DC components of the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component comprises: The second-order band-stop filter with twice the grid frequency is used to filter out the twice-frequency AC components in the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component, respectively, and the DC components of the positive-sequence active component, the positive-sequence reactive component, the negative-sequence active component and the negative-sequence reactive component are obtained accordingly.

5. A reactive current control method, characterized in that: include: The reactive current command generation method according to any one of claims 1 to 4 is used to obtain the positive sequence reactive current Axis component command value, negative sequence reactive current Axis component command value and negative sequence reactive current Axis component command value; According to the positive sequence reactive current Axis component command value, negative sequence reactive current Axis component command value and negative sequence reactive current The axis component command value controls the energy storage converter during the asymmetric low voltage ride-through process.

6. A reactive current control method according to claim 5, characterized in that: The controlling of the energy storage converter during the asymmetric low voltage ride-through process includes: The positive sequence active current Axis set value Positive sequence active current Axis feedback value The difference is input into regulator, obtain the first output; and convert the positive sequence active current Axis feedback value Input to Axis and Shaft decoupler , and obtain the second output; The positive sequence reactive current Axis component command value Positive sequence reactive current Axis feedback value The difference is input into regulator, and obtain the third output; and convert the positive sequence reactive current Axis feedback value Input to Axis and Shaft decoupler , and obtain the fourth output; The negative sequence reactive current Axis component command value and negative sequence active current Axis feedback value The difference is input into regulator, and obtain the fifth output; and convert the negative sequence active current Axis feedback value Input to Axis and Shaft decoupler , and obtain the sixth output; The negative sequence reactive current Axis component command value Negative sequence reactive current Axis feedback value The difference is input into regulator, and obtain the seventh output; and convert the negative sequence reactive current Axis feedback value Input to Axis and Shaft decoupler , and obtain the eighth output; The first output and the positive sequence active component Sum and subtract from the fourth output to obtain the ninth output; The second output, the third output and the positive sequence active component Sum and get the tenth output; The fifth output, the eighth output and the negative sequence active component Sum and get the eleventh output; The seventh output and negative sequence reactive component Sum and subtract from the sixth output to obtain the twelfth output; Combined with the grid voltage angular frequency The negative value of Coordinate transformation, get the thirteenth output; and combined with the grid voltage angular frequency The negative value of Coordinate transformation to obtain the fourteenth output; Add the thirteenth output and the fourteenth output to obtain the fifteenth output; The fifteenth output is pulse-width modulated to obtain a control signal for controlling the energy storage converter.

7. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of the reactive current instruction generating method as claimed in any one of claims 1 to 4 when executing the computer program.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the reactive current instruction generation method according to any one of claims 1 to 4 are implemented.

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