Control method and device of converter, converter, electronic equipment and storage medium

Abstract

The application discloses a control method and device of a converter, the converter, electronic equipment and storage medium, and belongs to the technical field of power system control. The method comprises the following steps: in the case that it is determined that a power grid fails, impedance identification results of the power grid are acquired; based on the impedance identification results, a target reactive current reference value is determined; and based on the target reactive current reference value, the output current of the converter is controlled. The method can provide reactive current support meeting the fault ride-through requirement during the power grid failure by introducing the impedance identification results of the power grid into the current loop of the converter, control the output current of the converter, effectively suppress the oscillation phenomenon of the grid-connected point current and voltage, be suitable for weak power grid working conditions, and reduce the fault ride-through risk under the weak power grid.

Description

Technical Field

[0001] This application belongs to the field of power system control technology, and in particular relates to a control method, device, converter, electronic equipment and storage medium for a converter. Background Technology

[0002] New energy power generation devices (such as wind power and photovoltaic power) transmit electrical energy to the power grid through grid-connected converters. According to the fault ride-through requirements, the grid-connected converter needs to maintain connection with the grid during grid voltage faults and simultaneously output reactive current to the grid to support the grid voltage.

[0003] In weak grid scenarios, the reactive current injected by the grid-connected converter significantly affects the grid voltage amplitude. For example, when a shallow voltage dip occurs in the grid, the reactive current output by the converter quickly raises the grid connection voltage. Since the reactive current output by the converter is usually determined based on the real-time monitored grid connection voltage, it stops outputting supporting reactive current when the grid connection voltage recovers. If the actual grid fault is not eliminated, the grid connection voltage will drop again, and the converter will output reactive current to support the grid. Under this condition, the repeated output and removal of reactive current by the converter will cause continuous oscillations in the grid current and voltage. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a control method, device, converter, electronic equipment, and storage medium for a converter, which can provide reactive current support that meets the fault ride-through requirements during grid faults, while effectively suppressing the oscillation of current and voltage at the grid connection point.

[0005] In a first aspect, this application provides a control method for a converter, wherein the converter is connected to the power grid at a grid connection point, the method comprising:

[0006] If a fault is determined to have occurred in the power grid, the impedance identification result of the power grid is obtained;

[0007] Based on the impedance identification results, the target reactive current reference value is determined;

[0008] The output current of the converter is controlled based on the target reactive current reference value.

[0009] According to the converter control method of this application, by obtaining the impedance identification result of the power grid when a fault occurs, and determining the target reactive current reference value of the converter based on the impedance identification result, the impedance identification result of the power grid is introduced into the current loop of the converter to control the output current of the converter. This can provide reactive current support that meets the fault ride-through requirements during power grid faults, while effectively suppressing the oscillation phenomenon of current and voltage at the grid connection point. It can adapt to weak power grid conditions and reduce the fault ride-through risk under weak power grid conditions.

[0010] According to one embodiment of this application, determining the target reactive current reference value based on the impedance identification result includes:

[0011] Based on the impedance identification results, the proportional gain and damping gain are determined;

[0012] Based on the impedance identification results, the proportional gain, and the damping gain, the target reactive current reference value is determined.

[0013] According to one embodiment of this application, determining the target reactive current reference value based on the impedance identification result, the proportional gain, and the damping gain includes:

[0014] Obtain the direct-axis voltage component, direct-axis voltage reference value, and direct-axis voltage change rate of the grid connection point;

[0015] The target reactive current reference value is determined based on the direct-axis voltage component, the direct-axis voltage reference value, the direct-axis voltage change rate, the impedance identification result, the proportional gain, and the damping gain.

[0016] According to one embodiment of this application, the formula is applied.

[0017]

[0018] Determine the target reactive current reference value;

[0019] in, The target reactive current reference value is... The direct-axis voltage component, This is the direct-axis voltage reference value. The direct-axis voltage change rate, The impedance identification result is as follows. The proportional gain, Let be the damping gain.

[0020] According to one embodiment of this application, obtaining the impedance identification result of the power grid includes:

[0021] Obtain the direct-axis voltage component, direct-axis voltage reference value, and reactive current increment at the grid connection point;

[0022] The impedance identification result is obtained based on the direct-axis voltage component, the direct-axis voltage reference value, and the reactive current increment.

[0023] According to one embodiment of this application, the impedance identification result is obtained by processing a first-order low-pass filter.

[0024] According to one embodiment of this application, controlling the output current of the converter based on the target reactive current reference value includes:

[0025] Based on the target reactive current reference value, determine the target active current reference value;

[0026] The output current of the converter is controlled based on the target reactive current reference value and the target active current reference value.

[0027] According to one embodiment of this application, controlling the output current of the converter based on the target reactive current reference value and the target active current reference value includes:

[0028] A first voltage command is generated based on the current feedback value of the converter, the target reactive current reference value, and the target active current reference value;

[0029] Based on the first voltage command, coordinate transformation and pulse width modulation are performed to generate a first drive signal. The first drive signal is used to drive the power module of the converter to operate, so as to adjust the output current of the converter.

[0030] Secondly, this application provides a control device for a converter, wherein the converter is connected to the power grid at a grid connection point, and the control device includes:

[0031] The first processing module is used to obtain the impedance identification result of the power grid when it is determined that a fault has occurred in the power grid.

[0032] The second processing module is used to determine the target reactive current reference value based on the impedance identification result.

[0033] The third processing module is used to control the output current of the converter based on the target reactive current reference value.

[0034] Thirdly, this application provides a converter, comprising:

[0035] The control device for the converter as described in the second aspect above.

[0036] Fourthly, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the converter control method described in the first aspect above.

[0037] Fifthly, this application provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the converter control method as described in the first aspect above.

[0038] In a sixth aspect, this application provides a computer program product, including a computer program that, when executed by a processor, implements the converter control method as described in the first aspect above.

[0039] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0040] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0041] Figure 1 This is one of the flowcharts illustrating the control method for a converter provided in this application embodiment;

[0042] Figure 2 This is a second schematic flowchart of the converter control method provided in the embodiments of this application;

[0043] Figure 3 This is one of the simulation diagrams of the reactive current of the converter provided in the embodiments of this application;

[0044] Figure 4 This is the second simulation diagram of the reactive current of the converter provided in the embodiments of this application;

[0045] Figure 5 This is a schematic diagram of the control device for the converter provided in the embodiments of this application;

[0046] Figure 6 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0048] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0049] The control method, control device, converter, electronic device, and readable storage medium of the converter provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0050] The converter control method provided in this application embodiment can be executed by a converter or a functional module or functional entity in the converter that can implement the converter control method.

[0051] In this embodiment of the application, the converter is connected to the grid at the grid connection point. The converter can output reactive current to the grid to provide support when a grid fault occurs, and has fault ride-through capability.

[0052] It should be noted that the converter control method of this application embodiment can be applied to weak grid scenarios, and the short-circuit ratio (SCR) of the grid connected to the converter can be less than or equal to 3.

[0053] In this embodiment of the application, a power metering device can be set up at the grid connection point to sample the voltage, current and other data of the grid connection point in real time, so as to obtain the electrical parameter set of the grid connection point.

[0054] It should be noted that the electrical parameter set of the grid connection point includes one or more electrical parameters that characterize the electrical state of the grid connection point. These parameters may include real-time sampled data of the grid connection point (such as voltage, current, etc.) or electrical quantities (such as power, etc.) calculated based on the real-time sampled data.

[0055] In practice, for a three-phase power grid, by sampling three-phase voltage and current data in real time, parameters such as direct-axis (d-axis) voltage component, quadrature-axis (q-axis) voltage component, direct-axis current component, and quadrature-axis current component can be calculated and decoupled. The electrical parameter set can include parameters such as three-phase voltage, current, direct-axis voltage component, quadrature-axis voltage component, direct-axis current component, and quadrature-axis current component.

[0056] like Figure 1As shown, the control method of the converter includes steps 110, 120 and 130.

[0057] Step 110: If a fault is determined in the power grid, determine the impedance identification result of the power grid.

[0058] Understandably, one can determine whether a fault has occurred in the power grid connected to the converter by collecting one or more electrical parameters from the electrical parameters of the grid connection point.

[0059] In actual implementation, a direct-axis voltage reference value can be preset. As the reference voltage for the power grid, the three-phase voltage is sampled in real time, and the current direct-axis voltage component is obtained through decoupling calculation. The direct-axis voltage component is compared with the direct-axis voltage reference value to detect whether there is an abnormal voltage drop in the power grid and to determine the fault status of the power grid.

[0060] For example, when the direct-axis voltage component Less than the direct axis voltage reference value When calculating the direct-axis voltage component and direct-axis voltage reference value The absolute value of the difference is used to determine if the voltage drop in the power grid is abnormal and a fault has occurred when the absolute value of the difference is less than the preset threshold for a duration exceeding the preset duration.

[0061] In this step, when a fault is detected in the power grid, an online identification algorithm can be used to estimate the impedance of the power grid in real time, and smoothing techniques such as filters can be combined to suppress noise interference and obtain reliable impedance identification results of the power grid.

[0062] In some embodiments, obtaining the impedance identification results of the power grid includes:

[0063] Obtain the direct-axis voltage component, direct-axis voltage reference value, and reactive current increment at the grid connection point;

[0064] The impedance identification results are obtained based on the direct-axis voltage component, the direct-axis voltage reference value, and the reactive current increment.

[0065] In this embodiment, the impedance identification result of the power grid can be determined based on the direct-axis voltage component, the direct-axis voltage reference value, and the reactive current increment in the electrical parameter set of the grid connection point.

[0066] It is understandable that the reactive current increment can be the change of the quadrature axis current component relative to its reference value or historical value. When a voltage fault occurs in the power grid, the converter will output reactive current to support the power grid, and the reactive current increment will not be 0. When no voltage fault occurs in the power grid, the reactive current increment will be 0.

[0067] In practice, the formula can be applied.

[0068]

[0069] Obtain the impedance of the power grid.

[0070] in, The impedance of the power grid, For the direct-axis voltage component, This is the direct-axis voltage reference value. This represents the increase in reactive current.

[0071] In some embodiments, the impedance identification results of the power grid can be obtained by processing a first-order low-pass filter.

[0072] In this embodiment, a first-order low-pass filter is used to smooth the grid impedance, which can effectively suppress the disturbance caused by the mutual coupling between the converter output current and the grid, and significantly improve the accuracy and reliability of the impedance identification results.

[0073] In practice, the impedance identification result obtained by processing with a first-order low-pass filter can be as follows:

[0074]

[0075] in, The impedance identification result is obtained by processing a first-order low-pass filter. The impedance of the power grid, This is the weighting factor for the filter, with a value ranging from 0 to 1. This indicates the sampling time sequence number corresponding to the converter sampling period. This is the increase in reactive current. , For the direct-axis voltage component, This is the reference value for the direct-axis voltage.

[0076] Step 120: Based on the impedance identification results, determine the target reactive current reference value.

[0077] Understandably, during a grid fault, the converter outputs reactive current to the grid to support the recovery of grid voltage. The reactive current reference value of the converter refers to the reference value of reactive current output set to meet the fault ride-through requirements.

[0078] In this embodiment, based on the impedance identification results and combined with one or more electrical parameters in the electrical parameter set, the target reactive current reference value of the converter is calculated, and the reactive current reference value of the converter is dynamically adjusted using the impedance identification results.

[0079] Step 130: Control the output current of the converter based on the target reactive current reference value.

[0080] In this step, the target reactive current reference value is added to the current loop control of the converter, and the output current of the converter is controlled in a closed loop based on the target reactive current reference value.

[0081] In actual operation, the feedback value of the converter output current can be sampled in real time, the deviation between the feedback value and the reference value can be calculated, and the output current of the converter can be controlled according to the deviation, so that the output current of the converter can quickly and accurately follow the current reference value.

[0082] In related technologies, the output reactive current is usually determined based on the real-time monitoring of the grid connection point voltage. When the grid connection point voltage is detected to be restored, the supporting reactive current is no longer output. If the actual grid fault is not eliminated, the grid connection point voltage will drop again, and the reactive current will be output again to support the grid. Under this operating condition, the repeated output and removal of reactive current by the converter will cause continuous oscillation of the grid connection current and voltage.

[0083] In this embodiment, when a grid fault is detected, the impedance identification result of the grid is obtained, and the target reactive current reference value of the converter is determined based on the impedance identification result. Compared with the control strategies in related technologies that use fixed values ​​or rely solely on voltage feedforward, this embodiment introduces real-time impedance identification results into the current loop. This allows for real-time correction of the instantaneous gain and response speed of the current loop to voltage deviation, making the output change of the converter's reactive current smoother. This reduces the impact of the converter output on the grid voltage and cuts off the positive feedback path of "voltage-reactive current" in related technologies. During voltage disturbances, the reactive current compensated by the converter can quickly reach the fault ride-through index requirements, while effectively suppressing the oscillation phenomenon of current and voltage at the grid connection point. This approach can adapt to weak grid conditions and reduce the fault ride-through risk under weak grid conditions.

[0084] It should be noted that when a grid fault occurs, the impedance identification results of the grid are obtained, the target reactive current reference value of the converter is calculated, and the real-time impedance identification results are introduced into the current loop. When the grid is operating normally, the current loop of the converter can maintain the set control strategy without the need to introduce impedance identification results to adjust the current reference value, which can effectively reduce the control burden during normal system operation.

[0085] According to the converter control method provided in the embodiments of this application, by obtaining the impedance identification result of the power grid when a fault occurs, and determining the target reactive current reference value of the converter based on the impedance identification result, the impedance identification result of the power grid is introduced into the current loop of the converter to control the output current of the converter. This can provide reactive current support that meets the fault ride-through requirements during power grid faults, while effectively suppressing the oscillation phenomenon of current and voltage at the grid connection point. It can adapt to weak power grid conditions and reduce the fault ride-through risk under weak power grid conditions.

[0086] In some embodiments, determining the target reactive current reference value based on the impedance identification results may include:

[0087] Based on the impedance identification results, determine the proportional gain and damping gain;

[0088] Based on the impedance identification results, proportional gain, and damping gain, the target reactive current reference value is determined.

[0089] Understandably, by using the proportional gain (P coefficient) and damping gain (D coefficient) in synergy to achieve current loop control of the converter, the dynamic response and steady-state accuracy of the converter can be optimized while enhancing system stability. Under weak grid conditions, it can effectively suppress the oscillation of current and voltage at the grid connection point.

[0090] In this embodiment, by dynamically adjusting the proportional gain and damping gain based on the real-time grid impedance identified online (i.e., the impedance identification result), it is possible to adapt to weak grid conditions with different impedance characteristics, thereby improving the poor adaptability caused by fixed control parameters in related technologies.

[0091] In some embodiments, a target reactive current reference value is determined based on impedance identification results, proportional gain, and damping gain, including:

[0092] Obtain the direct-axis voltage component, direct-axis voltage reference value, and direct-axis voltage change rate at the grid connection point;

[0093] The target reactive current reference value is determined based on the direct-axis voltage component, the direct-axis voltage reference value, the direct-axis voltage change rate, the impedance identification results, the proportional gain, and the damping gain.

[0094] In this embodiment, the real-time sampled data at the grid connection point is calculated to obtain the direct-axis voltage component, the direct-axis voltage reference value, and the direct-axis voltage change rate. Combined with the impedance identification results, proportional gain, and damping gain, the target reactive current reference value of the converter is determined.

[0095] It is understandable that the rate of change of direct-axis voltage reflects the speed and direction of change of the direct-axis voltage component over time.

[0096] In practice, the direct-axis voltage change rate can be calculated by combining the sampled voltage difference with low-pass filtering.

[0097] For example, applying formulas

[0098]

[0099] Determine the rate of change of the direct-axis voltage.

[0100] in, The direct-axis voltage change rate, For the direct-axis voltage component, This is the sampling time sequence number corresponding to the converter's sampling period. For the Karpulas operator, The sampling time interval of the converter. The filtering time constant is the voltage derivative.

[0101] In some embodiments, the formula is applied.

[0102]

[0103] Determine the target reactive current reference value.

[0104] in, The target reactive current reference value, For the direct-axis voltage component, This is the direct-axis voltage reference value. The direct-axis voltage change rate, For impedance identification results, For proportional gain, This represents the damping gain.

[0105] In this embodiment, the proportional gain It can be compared with the impedance identification results The reciprocal of the product is in a preset multiple relationship (such as 0.6-0.8).

[0106] For example, ,or, ,or, .

[0107] In this embodiment, the formula can be applied.

[0108]

[0109] Determine the damping gain .

[0110] in, The system's undamped natural frequency, For the damping ratio, a value of 0.707 can be used. The equivalent damping coefficient of the system is... The angular frequency of the power grid. For the control delay duration of the converter, The filtering time constant is the voltage derivative. The impedance identification results are shown.

[0111] It should be noted that the undamped natural frequency of the system refers to the angular frequency of the system containing the converter when it oscillates freely under ideal conditions without damping. The equivalent damping coefficient of the system is a dimensionless ratio used to quantify the strength of the actual damping effect of the system.

[0112] In practice, the formula can be applied.

[0113]

[0114] Determine the undamped natural frequency of the system .

[0115] in, The angular frequency of the power grid. For the control delay duration of the converter, The filtering time constant is the voltage derivative. The impedance identification results are shown.

[0116] In some embodiments, controlling the output current of the converter based on a target reactive current reference value includes:

[0117] Determine the target active current reference value based on the target reactive current reference value;

[0118] The output current of the converter is controlled based on the target reactive current reference value and the target active current reference value.

[0119] Understandably, the converter's current loop is used to achieve closed-loop control of the direct-axis current (corresponding to active current) and quadrature-axis current (corresponding to reactive current), obtain target reactive current reference values ​​and target active current reference values, coordinate the control of the converter's output active and reactive currents, maintain the stability of the converter's operation, and effectively reduce oscillation phenomena.

[0120] It should be noted that when a grid fault occurs, priority should be given to ensuring that the output reactive current meets the fault ride-through requirements to support the grid. The active current output capability of the converter is constrained by the reactive current. The target active current reference value of the converter can be calculated based on the target reactive current reference value.

[0121] In actual implementation, the formula is applied.

[0122]

[0123] Determine the target active current reference value.

[0124] in, To take the smaller function, The target active current reference value, The target reactive current reference value, For apparent current limits, The reactive current allowable value gain coefficient, This is the preset active current command value. and It can be adjusted according to user needs.

[0125] In some embodiments, controlling the output current of the converter based on a target reactive current reference value and a target active current reference value includes:

[0126] The first voltage command is generated based on the current feedback value of the converter, the target reactive current reference value, and the target active current reference value.

[0127] Based on the first voltage command, coordinate transformation and pulse width modulation are performed to generate a first drive signal. The first drive signal is used to drive the power module of the converter to adjust the output current of the converter.

[0128] In this embodiment, the current feedback value of the converter can be sampled in real time, the deviation between the current reference value (including the target reactive current reference value and the target active current reference value) and the current feedback value can be calculated, a first voltage command can be generated based on the deviation, and the first voltage command can be subjected to coordinate transformation and pulse width modulation to generate a first drive signal.

[0129] In actual implementation, the first drive signal can be a pulse width modulation (PWM) signal. The first drive signal can drive the power module of the converter to operate and execute the corresponding current output control, so that the output current of the converter can quickly and accurately follow the current reference value.

[0130] The following is a specific example.

[0131] like Figure 2 As shown, for a three-phase (ABC) power grid, the sampling and calculation unit can sample the three-phase voltage in real time. u a , u b , u c and three-phase current i a , i b , i c The decoupled direct-axis and quadrature-axis voltages and currents are calculated, and the real-time direct-axis voltage component is output. Direct-axis voltage reference value Identified grid impedance Direct-axis current component i d quadrature axis current component i q Parameters such as these.

[0132] In this embodiment, the grid impedance can be smoothly identified using a first-order low-pass filter. The impedance identification results were obtained. .

[0133] The current command generation unit is used based on the impedance identification results. Set reference values ​​for the direct-axis and quadrature-axis currents, including the target active current reference value. and target reactive current reference value .

[0134] The current loop control unit is used to achieve closed-loop tracking control of the direct-axis and quadrature-axis currents, based on the reference value obtained by the current command generation unit. , The feedback value obtained by the sampling calculation unit is () i d , i q The deviation generates the corresponding first voltage command () v d , v q ).

[0135] The first voltage command is then input to the coordinate transformation and PWM waveform generation unit. After coordinate transformation and pulse width modulation processing, the first drive signal S for driving the power module is finally generated. a S b S c It executes current output control for the corresponding phase, enabling the converter's output current to quickly and accurately follow the current reference value.

[0136] In this embodiment, the current command generation unit is activated only when there is a grid fault, and the reactive current reference value is adjusted based on the impedance identification result of the grid.

[0137] With the grid SCR set to 1.5, a voltage dip fault was simulated in the grid under the same experimental conditions. The control strategies that rely on voltage feedforward in related technologies and the control strategy that adjusts the reactive current reference value based on impedance identification results in the embodiments of this application were compared.

[0138] like Figure 3 As shown, the control strategy that relies solely on voltage feedforward will cause continuous oscillation of reactive current, which has not stabilized from 4.2 seconds to 5.5 seconds.

[0139] like Figure 4 As shown, the control strategy of adjusting the reactive current reference value using impedance identification results can quickly stabilize the reactive current during voltage disturbances, with an oscillation duration of approximately 0.1 seconds.

[0140] It should be noted that, Figure 3 and Figure 4 The blue line represents the converter reactive current setpoint (the corresponding reactive current reference value when the control strategy adjusts the reactive current reference value using impedance identification results). The red line represents the real-time reactive current feedback value of the converter. .

[0141] In this embodiment, real-time impedance identification results are introduced into the current loop, cutting off the positive feedback path of "voltage-reactive current" in related technologies. During voltage disturbances, the reactive current compensated by the converter can quickly reach the fault ride-through index requirements, while effectively suppressing the oscillation phenomenon of current and voltage at the grid connection point. It can adapt to weak grid conditions with different impedance characteristics and reduce the fault ride-through risk under weak grid conditions.

[0142] The converter control method provided in this application can be executed by a converter control device. This application uses the example of a converter control device executing the converter control method to illustrate the converter control device provided in this application.

[0143] This application also provides a control device for a converter, wherein the converter is connected to the power grid at the grid connection point.

[0144] like Figure 5 As shown, the control device for the converter includes:

[0145] The first processing module 510 is used to obtain the impedance identification result of the power grid when it is determined that a fault has occurred in the power grid.

[0146] The second processing module 520 is used to determine the target reactive current reference value based on the impedance identification results.

[0147] The third processing module 530 is used to control the output current of the converter based on the target reactive current reference value.

[0148] According to the converter control device provided in the embodiments of this application, by obtaining the impedance identification result of the power grid when a fault occurs, and determining the target reactive current reference value of the converter based on the impedance identification result, the impedance identification result of the power grid is introduced into the current loop of the converter to control the output current of the converter. During the power grid fault, reactive current support that meets the fault ride-through requirements can be provided, while effectively suppressing the oscillation phenomenon of current and voltage at the grid connection point. It can be adapted to weak power grid conditions and reduce the fault ride-through risk under weak power grid conditions.

[0149] In some embodiments, the second processing module 520 is configured to determine a target reactive current reference value based on the impedance identification result, including:

[0150] Based on the impedance identification results, determine the proportional gain and damping gain;

[0151] Based on the impedance identification results, proportional gain, and damping gain, the target reactive current reference value is determined.

[0152] In some embodiments, the second processing module 520 is configured to determine a target reactive current reference value based on impedance identification results, proportional gain, and damping gain, including:

[0153] Obtain the direct-axis voltage component, direct-axis voltage reference value, and direct-axis voltage change rate at the grid connection point;

[0154] The target reactive current reference value is determined based on the direct-axis voltage component, the direct-axis voltage reference value, the direct-axis voltage change rate, the impedance identification results, the proportional gain, and the damping gain.

[0155] In some embodiments, the second processing module 520 is used to apply the formula.

[0156]

[0157] Determine the target reactive current reference value;

[0158] in, The target reactive current reference value, For the direct-axis voltage component, This is the direct-axis voltage reference value. The direct-axis voltage change rate, For impedance identification results, For proportional gain, This represents the damping gain.

[0159] In some embodiments, the first processing module 510 is configured to obtain the impedance identification result of the power grid, including:

[0160] Obtain the direct-axis voltage component, direct-axis voltage reference value, and reactive current increment at the grid connection point;

[0161] The impedance identification results are obtained based on the direct-axis voltage component, the direct-axis voltage reference value, and the reactive current increment.

[0162] In some embodiments, the impedance identification result is obtained by processing a first-order low-pass filter.

[0163] In some embodiments, the third processing module 530 is configured to control the output current of the converter based on a target reactive current reference value, including:

[0164] Determine the target active current reference value based on the target reactive current reference value;

[0165] The output current of the converter is controlled based on the target reactive current reference value and the target active current reference value.

[0166] In some embodiments, the third processing module 530 is configured to control the output current of the converter based on a target reactive current reference value and a target active current reference value, including:

[0167] The first voltage command is generated based on the current feedback value of the converter, the target reactive current reference value, and the target active current reference value.

[0168] Based on the first voltage command, coordinate transformation and pulse width modulation are performed to generate a first drive signal. The first drive signal is used to drive the power module of the converter to adjust the output current of the converter.

[0169] The control device for the converter in the embodiments of this application can be an electronic device or a component in an electronic device, such as an integrated circuit or a chip.

[0170] The converter control device provided in this application embodiment can realize the various processes implemented in the above-described converter control method embodiment. To avoid repetition, it will not be described again here.

[0171] This application embodiment also provides a converter, which includes the control device for the converter as described above.

[0172] According to the converter provided in the embodiments of this application, by obtaining the impedance identification result of the power grid when a fault occurs, and determining the target reactive current reference value of the converter based on the impedance identification result, the impedance identification result of the power grid is introduced into the current loop of the converter to control the output current of the converter. During the power grid fault, reactive current support that meets the fault ride-through requirements can be provided, while effectively suppressing the oscillation phenomenon of current and voltage at the grid connection point. It can be adapted to weak power grid conditions and reduce the fault ride-through risk under weak power grid conditions.

[0173] In some embodiments, such as Figure 6 As shown, this application embodiment also provides an electronic device 600, including a processor 601, a memory 602, and a computer program stored in the memory 602 and executable on the processor 601. When the program is executed by the processor 601, it implements the various processes of the above-described converter control method embodiment and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0174] It should be noted that the electronic devices in the embodiments of this application include the mobile electronic devices and non-mobile electronic devices described above.

[0175] This application also provides a non-transitory computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the various processes of the above-described converter control method embodiments and achieves the same technical effect. To avoid repetition, it will not be described again here.

[0176] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0177] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described converter control method.

[0178] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0179] This application embodiment also provides a chip, which includes a processor and a communication interface. The communication interface is coupled to the processor. The processor is used to run programs or instructions to implement the various processes of the above-described converter control method embodiments and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0180] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0181] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0182] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0183] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0184] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0185] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A control method for a converter, characterized in that, The converter is connected to the grid at a grid connection point, and the method includes: If a fault is determined to have occurred in the power grid, the impedance identification result of the power grid is obtained; Based on the impedance identification results, the target reactive current reference value is determined; Based on the target reactive current reference value, control the output current of the converter; The determination of the target reactive current reference value based on the impedance identification result includes: Based on the impedance identification results, the proportional gain and damping gain are determined; Based on the impedance identification results, the proportional gain, and the damping gain, the target reactive current reference value is determined. The determination of the target reactive current reference value based on the impedance identification result, the proportional gain, and the damping gain includes: Obtain the direct-axis voltage component, direct-axis voltage reference value, and direct-axis voltage change rate of the grid connection point; The target reactive current reference value is determined based on the direct-axis voltage component, the direct-axis voltage reference value, the direct-axis voltage change rate, the impedance identification result, the proportional gain, and the damping gain. Application formula Determine the target reactive current reference value; in, The target reactive current reference value is... The direct-axis voltage component, This is the direct-axis voltage reference value. The direct-axis voltage change rate, The impedance identification result is as follows. The proportional gain, Let be the damping gain.

2. The control method for the converter according to claim 1, characterized in that, The process of obtaining the impedance identification results of the power grid includes: Obtain the direct-axis voltage component, direct-axis voltage reference value, and reactive current increment at the grid connection point; The impedance identification result is obtained based on the direct-axis voltage component, the direct-axis voltage reference value, and the reactive current increment.

3. The control method for the converter according to claim 2, characterized in that, The impedance identification result is obtained by processing a first-order low-pass filter.

4. The control method for the converter according to any one of claims 1-3, characterized in that, The step of controlling the output current of the converter based on the target reactive current reference value includes: Based on the target reactive current reference value, determine the target active current reference value; The output current of the converter is controlled based on the target reactive current reference value and the target active current reference value.

5. The control method for the converter according to claim 4, characterized in that, The step of controlling the output current of the converter based on the target reactive current reference value and the target active current reference value includes: A first voltage command is generated based on the current feedback value of the converter, the target reactive current reference value, and the target active current reference value; Based on the first voltage command, coordinate transformation and pulse width modulation are performed to generate a first drive signal. The first drive signal is used to drive the power module of the converter to operate, so as to adjust the output current of the converter.

6. A control device for a converter, characterized in that, The converter is connected to the grid at the grid connection point, and the control device includes: The first processing module is used to obtain the impedance identification result of the power grid when it is determined that a fault has occurred in the power grid. The second processing module is used to determine the target reactive current reference value based on the impedance identification result. The third processing module is used to control the output current of the converter based on the target reactive current reference value. The second processing module is used to determine a target reactive current reference value based on the impedance identification result, including: Based on the impedance identification results, the proportional gain and damping gain are determined; Based on the impedance identification results, the proportional gain, and the damping gain, the target reactive current reference value is determined. The second processing module is used to determine the target reactive current reference value based on the impedance identification result, the proportional gain, and the damping gain, including: Obtain the direct-axis voltage component, direct-axis voltage reference value, and direct-axis voltage change rate of the grid connection point; The target reactive current reference value is determined based on the direct-axis voltage component, the direct-axis voltage reference value, the direct-axis voltage change rate, the impedance identification result, the proportional gain, and the damping gain. The second processing module is used to apply the formula. Determine the target reactive current reference value; in, The target reactive current reference value is... The direct-axis voltage component, This is the direct-axis voltage reference value. The direct-axis voltage change rate, The impedance identification result is as follows. The proportional gain, Let be the damping gain.

7. A converter, characterized in that, include: The control device for the converter as described in claim 6.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the control method of the converter as described in any one of claims 1-5.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the control method for the converter as described in any one of claims 1-5.

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