Filter parameter determination method and apparatus, computer device

Abstract

The application relates to a filter parameter determination method and device and a computer device. The method comprises the following steps: acquiring a first parameter range of a first filter in a first power transmission line in which an alternator transmits power to an energy storage system, and acquiring a second parameter range of a second filter in a second power transmission line in which a direct-current generator transmits power to the energy storage system; determining a target parameter range shared by the first filter and the second filter according to the first parameter range and the second parameter range; acquiring a total ripple current effective value target function and a ripple current difference value target function, and determining a target parameter of the first filter and a target parameter of the second filter according to the target parameter range, the total ripple current effective value target function and the ripple current difference value target function. The power supply quality when the alternator and the direct-current generator cooperatively supply power to the energy storage system can be improved by using the method.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to a method and apparatus for determining filter parameters, and computer equipment. Background Technology

[0002] In new energy power supply systems, the synergistic application of AC generators and DC generators is becoming increasingly widespread. For example, AC generators include diesel generators, and DC generators can include photovoltaic generators. The electrical energy generated by both diesel generators and photovoltaic generators can be output to energy storage systems.

[0003] In related technologies, both the transmission lines for AC generators to transmit power to energy storage systems and the transmission lines for DC generators to transmit power to energy storage systems are equipped with power conversion devices and filters. The filters are used to filter out harmonics generated by the high-frequency switching of the power conversion devices. The filter parameters of the filters in the transmission lines for AC generators to transmit power to energy storage systems and the filters in the transmission lines for DC generators to transmit power to energy storage systems are designed independently.

[0004] However, the method of determining the filter parameters in the relevant technology has the problem that the sum of the ripple current output by the AC generator to the energy storage system and the ripple current output by the DC generator to the energy storage system is large, and the absolute value of the difference between the ripple current output by the AC generator to the energy storage system and the ripple current output by the DC generator to the energy storage system is large, which leads to the problem of poor power supply quality when the AC generator and the DC generator work together to supply power to the energy storage system. Summary of the Invention

[0005] Based on this, this application provides a method and apparatus for determining filter parameters, as well as a computer device, which can improve the power supply quality when an AC generator and a DC generator work together to supply power to an energy storage system.

[0006] Firstly, this application provides a method for determining filter parameters, the method comprising:

[0007] Obtain the first parameter range of the first filter in the first transmission line for transmitting power from an AC generator to an energy storage system, and obtain the second parameter range of the second filter in the second transmission line for transmitting power from a DC generator to an energy storage system;

[0008] Based on the first parameter range and the second parameter range, determine the target parameter range shared by the first filter and the second filter;

[0009] Obtain the objective function for the total effective value of ripple current and the objective function for the difference of ripple current. Based on the target parameter range, the objective function for the total effective value of ripple current, and the objective function for the difference of ripple current, determine the target parameters for the first filter and the target parameters for the second filter.

[0010] In some embodiments, obtaining the first parameter range of a first filter in a first transmission line that transmits power from an AC generator to an energy storage system includes:

[0011] Based on the output parameters of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line, the inductance value range of the inductor on the first power conversion device side of the first filter is determined.

[0012] Based on the output parameters of the alternator, determine the capacitance range of the capacitors in the first filter;

[0013] The inductance range of the inductor on the first power converter side in the first filter is determined based on the inductance range of the inductor on the first power converter side in the first filter, the capacitance range of the capacitor in the first filter, the main harmonic order of the first power converter, and the grid-connected current of the first power converter.

[0014] The range of inductance values ​​of the inductor on the first power conversion device side of the first filter, the range of capacitance values ​​of the capacitor in the first filter, and the range of inductance values ​​of the inductor on the alternator side of the first filter are determined as the first parameter range of the first filter.

[0015] In some embodiments, determining the inductance range of the inductor on the first power conversion device side of the first filter based on the output parameters of the alternator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line includes:

[0016] Determine the output current of the AC generator based on the effective voltage value and power in the output parameters of the AC generator;

[0017] Obtain the maximum per-unit value of the ripple current of the first power conversion device in the first transmission line;

[0018] Based on the maximum per-unit value of the ripple current of the first power conversion device in the first transmission line, the output current of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line, the inductance range of the inductor on the side of the first power conversion device in the first filter is determined.

[0019] In some embodiments, obtaining the second parameter range of the second filter in the second transmission line that transmits power from the DC generator to the energy storage system includes:

[0020] Based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, and the switching frequency of the second power conversion device in the first transmission line, determine the inductance range of the inductor on the second power conversion device side of the second filter.

[0021] The capacitance range of the capacitor in the second filter is determined based on the peak-to-peak value of the ripple current of the inductor on the side of the second power conversion device in the second filter, the switching frequency of the second power conversion device in the first transmission line, and the total ripple voltage.

[0022] The range of inductance values ​​of the inductor on the second power conversion device side of the second filter and the range of capacitance values ​​of the capacitor in the second filter are determined as the second parameter range of the second filter.

[0023] In some embodiments, obtaining the objective function for the total ripple current RMS value and the objective function for the ripple current difference includes:

[0024] Objective functions for obtaining the first effective value of the ripple current of the first power conversion device in the first transmission line and objective functions for obtaining the second effective value of the ripple current of the second power conversion device in the second transmission line;

[0025] The sum of the objective function for the first effective value of ripple current and the objective function for the second effective value of ripple current is determined as the objective function for the total effective value of ripple current.

[0026] The absolute value of the difference between the objective function for the first effective value of ripple current and the objective function for the second effective value of ripple current is determined as the objective function for the ripple current difference.

[0027] In some embodiments, obtaining the objective function for the effective value of the first ripple current of the first power conversion device in the first transmission line includes:

[0028] Based on the transformation parameters of the first power conversion device in the first transmission line, determine the per-unit value of the ripple current of the first power conversion device in the first transmission line;

[0029] The objective function for the first ripple current value of the first power conversion device in the first transmission line is determined based on the per-unit value of the ripple current of the first power conversion device in the first transmission line, the conversion parameters of the first power conversion device in the first transmission line, the bus voltage on the energy storage system side, and the inductance value of the inductor on the power conversion device side of the first filter.

[0030] Based on the objective function of the first ripple current value of the first power conversion device in the first transmission line, the objective function of the effective value of the first ripple current of the first power conversion device in the first transmission line is determined.

[0031] In some embodiments, obtaining the objective function for the effective value of the second ripple current of the second power conversion device in the second transmission line includes:

[0032] The objective function for the second ripple current value of the second power conversion device in the second transmission line is determined based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, the switching frequency of the first power conversion device in the first transmission line, and the inductance value of the inductor on the second power conversion device side in the second filter.

[0033] Based on the objective function of the second ripple current value of the second power conversion device in the second transmission line, determine the objective function of the effective value of the second ripple current of the second power conversion device in the second transmission line.

[0034] In some embodiments, the target parameters of the first filter and the target parameters of the second filter are determined based on the target parameter range, the target function of the total ripple current RMS value, and the target function of the ripple current difference, including:

[0035] Based on the target parameter range, determine the initial parameters of the first filter and the initial parameters of the second filter;

[0036] Based on the objective function of the total ripple current RMS value and the objective function of the ripple current difference, the initial parameters of the first filter and the initial parameters of the second filter are iteratively updated until the iteration condition is met or the number of iterations is equal to the preset number of iterations, so as to obtain the target parameters of the first filter and the target parameters of the second filter.

[0037] Secondly, this application provides a filter parameter determination apparatus, the apparatus comprising:

[0038] The acquisition module is used to acquire the first parameter range of the first filter in the first transmission line for transmitting power from the AC generator to the energy storage system, and to acquire the second parameter range of the second filter in the second transmission line for transmitting power from the DC generator to the energy storage system.

[0039] The parameter range determination module is used to determine the target parameter range shared by the first filter and the second filter based on the first parameter range and the second parameter range.

[0040] The target parameter determination module is used to obtain the target function of the total ripple current RMS value and the target function of the ripple current difference, and to determine the target parameters of the first filter and the target parameters of the second filter based on the target parameter range, the target function of the total ripple current RMS value and the target function of the ripple current difference.

[0041] Thirdly, this application provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods in the first aspect.

[0042] In the technical solution provided in this application embodiment, a target parameter range shared by the first filter and the second filter is determined based on the first parameter range and the second parameter range. This ensures that the parameters of both the first filter and the second filter are selected within the target parameter range, guaranteeing performance matching between the first filter and the second filter during collaborative operation. This enhances the consistency of filtering effects and helps reduce the absolute value of the difference between the ripple current output by the AC generator to the energy storage system and the ripple current output by the DC generator to the energy storage system. Furthermore, it reduces the selection complexity of the first filter and the second filter. Moreover, based on the target parameter range, the objective function of the total ripple current effective value, and the ripple current... The difference objective function determines the target parameters of the first filter and the second filter, ensuring that the determined target parameters of the first filter and the second filter not only meet the target parameter range, but also minimize the total ripple current effective value objective function and the ripple current difference objective function. This not only reduces the sum of the ripple current output from the AC generator to the energy storage system and the ripple current output from the DC generator to the energy storage system, but also reduces the absolute value of the difference between the ripple current output from the AC generator to the energy storage system and the ripple current output from the DC generator to the energy storage system, thereby improving the power supply quality when the AC generator and DC generator work together to supply power to the energy storage system. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 A schematic diagram of the power supply system provided for some embodiments;

[0045] Figure 2 A flowchart illustrating a method for determining filter parameters provided in some embodiments;

[0046] Figure 3 A flowchart illustrating a method for determining the range of first parameters of a first filter according to some embodiments;

[0047] Figure 4 A flowchart illustrating a method for determining the range of second parameters of a second filter as provided in some embodiments;

[0048] Figure 5 A schematic diagram illustrating how the target parameter range shared by the first and second filters is determined for some embodiments;

[0049] Figure 6 A flowchart illustrating a method for determining the objective function of the first ripple current effective value provided in some embodiments;

[0050] Figure 7 A flowchart illustrating a method for determining the objective function of the second ripple current effective value provided in some embodiments;

[0051] Figure 8 A flowchart illustrating a method for determining the target parameters of a first filter and a second filter, provided for some embodiments;

[0052] Figure 9 A flowchart illustrating a method for determining filter parameters provided in other embodiments;

[0053] Figure 10 A schematic diagram of the structure of a filter parameter determination device provided in some embodiments;

[0054] Figure 11 A schematic diagram of the structure of a computer device provided for some embodiments. Detailed Implementation

[0055] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0057] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, "multiple groups" means two or more, and "each" means each of the multiple, unless otherwise explicitly defined.

[0058] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0059] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0060] Unless otherwise specified, the order of execution steps in the embodiments of this application is not limited. It should also be noted that any step in the embodiments of this application can be executed independently, that is, the execution of any step in the above embodiments can be performed without depending on the execution of other steps.

[0061] Figure 1 A schematic diagram of the power supply system provided for some embodiments, such as Figure 1 As shown, the power supply system includes an AC generator, a DC generator, a first filter and a first power conversion device in the first transmission line from the AC generator to the energy storage system, and a second filter and a second power conversion device in the second transmission line from the DC generator to the energy storage system.

[0062] The methods in any embodiment of this application can be applied to a computer device or a processor in a computer device. Exemplarily, a computer device may include one or more of the following: a server, a mobile phone, a tablet computer, a computer with transceiver capabilities, a handheld computer, a desktop computer, a personal digital assistant, a portable media player, a smart speaker, a navigation device, a smartwatch, smart glasses, a smart necklace, and other wearable devices, a pedometer, a digital TV, a virtual reality (VR) device, an augmented reality (AR) device, a device in industrial control, a device in self-driving, a device in remote medical surgery, a device in a smart grid, a device in transportation safety, a device in a smart city, a device in a smart home, a vehicle, an in-vehicle device, an in-vehicle module, etc.

[0063] Figure 2 A flowchart illustrating a method for determining filter parameters provided in some embodiments, such as... Figure 2 As shown, the method includes the following steps:

[0064] S201. Obtain the first parameter range of the first filter in the first transmission line for transmitting power from the AC generator to the energy storage system, and obtain the second parameter range of the second filter in the second transmission line for transmitting power from the DC generator to the energy storage system.

[0065] For example, the AC generator in the embodiments of this application may include a diesel generator. In other embodiments, the AC generator may include a hydroelectric generator or a wind turbine generator, etc. For example, the DC generator in the embodiments of this application may include a photovoltaic generator. In other embodiments, the DC generator may include a fuel cell, etc.

[0066] An energy storage system may include multiple batteries, which may be connected in series, in parallel, or in a hybrid series-parallel configuration. The batteries are used to store electrical energy output from AC and DC generators.

[0067] A filter may include capacitors and inductors. For example, a filter may include an inductor on the power conversion device side, an inductor on the generator side, and a capacitor connected between the two inductors. The first terminal of the capacitor is connected between the two inductors, and the second terminal of the capacitor may be grounded.

[0068] In some embodiments, the first parameter range and the second parameter range may be preset ranges. In other embodiments, the first parameter range may be determined based on at least one of the parameters of the AC generator, the conversion parameters of the first power conversion device in the first transmission line, and the bus voltage on the energy storage system side, and the second parameter range may be determined based on at least one of the parameters of the DC generator, the conversion parameters of the second power conversion device in the second transmission line, and the bus voltage on the energy storage system side.

[0069] S202. Determine the target parameter range shared by the first filter and the second filter based on the first parameter range and the second parameter range.

[0070] In some embodiments, the intersection of the first parameter range and the second parameter range can be determined as the target parameter range. In other embodiments, a target boundary value can be determined based on the boundary values ​​of the first parameter range and the second parameter range; and a target parameter range can be determined based on the target boundary value. For example, the average of the boundary values ​​of the first parameter range and the second parameter range can be determined as the target boundary value.

[0071] S203. Obtain the objective function of the total ripple current RMS value and the objective function of the ripple current difference, and determine the objective parameters of the first filter and the objective parameters of the second filter based on the objective parameter range, the objective function of the total ripple current RMS value and the objective function of the ripple current difference.

[0072] In some embodiments, a genetic algorithm or a particle swarm optimization algorithm can be used to determine the target parameters of the first filter and the target parameters of the second filter based on the target parameter range, the target function of the total ripple current effective value, and the target function of the ripple current difference.

[0073] In the technical solution provided in this application embodiment, a target parameter range shared by the first filter and the second filter is determined based on the first parameter range and the second parameter range. This ensures that the parameters of both the first filter and the second filter are selected within the target parameter range, guaranteeing performance matching between the first filter and the second filter during collaborative operation. This enhances the consistency of filtering effects and helps reduce the absolute value of the difference between the ripple current output by the AC generator to the energy storage system and the ripple current output by the DC generator to the energy storage system. Furthermore, it reduces the selection complexity of the first filter and the second filter. Moreover, based on the target parameter range, the objective function of the total ripple current effective value, and the ripple current... The difference objective function determines the target parameters of the first filter and the second filter, ensuring that the determined target parameters of the first filter and the second filter not only meet the target parameter range, but also minimize the total ripple current effective value objective function and the ripple current difference objective function. This not only reduces the sum of the ripple current output from the AC generator to the energy storage system and the ripple current output from the DC generator to the energy storage system, but also reduces the absolute value of the difference between the ripple current output from the AC generator to the energy storage system and the ripple current output from the DC generator to the energy storage system, thereby improving the power supply quality when the AC generator and DC generator work together to supply power to the energy storage system.

[0074] Figure 3 A flowchart illustrating a method for determining the first parameter range of a first filter according to some embodiments, the method comprising:

[0075] S301. Based on the output parameters of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line, determine the inductance range of the inductor on the first power conversion device side of the first filter.

[0076] For example, the output parameters of an alternator may include the alternator's output power, the effective value of the alternator's output voltage, and the alternator's output current. For example, the alternator's output current can be determined based on the alternator's output power and the effective value of the alternator's output voltage. For instance, the alternator's output line voltage can be determined based on the alternator's output voltage; and the alternator's output current can be determined based on the alternator's output line voltage and output power.

[0077] For example, the conversion parameters of the first power conversion device may include the modulation ratio, the ripple coefficient, the switching frequency, and the switching period. In some embodiments, the ripple coefficient may be an intrinsic design parameter of the power conversion device.

[0078] In some embodiments, determining the inductance range of the inductor on the first power conversion device side of the first filter based on the output parameters of the alternator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line includes: determining the output current of the alternator based on the effective voltage value and output power in the output parameters of the alternator; obtaining the maximum value of the per-unit ripple current of the first power conversion device in the first transmission line; and determining the inductance range of the inductor on the first power conversion device side of the first filter based on the maximum value of the per-unit ripple current of the first power conversion device in the first transmission line, the output current of the alternator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line.

[0079] In some embodiments, the inductor on the first power conversion device side of the first filter The maximum value can be determined according to the following formula: ;in, For V L1_f The ratio of the effective value of the capacitor voltage to the effective value of the capacitor voltage, V L1_f Inductor Fundamental voltage drop at both ends; This represents the effective value of the voltage in the output parameters of an AC generator; Indicates the fundamental frequency of the AC generator output; This indicates the output current of the alternator.

[0080] For example, the output power of the AC generator is 30kW, and the effective value of the output voltage of the AC generator is V. g_rms The value is 230Vrms, therefore the output current of the AC generator is 43.5Arms, and the fundamental frequency is 50Hz. v_L1 If the value is 5%, then the inductor on the first power conversion device side of the first filter... The maximum value is .

[0081] In some embodiments, in the first transmission line that transmits power from the AC generator to the energy storage system, the current flowing through the inductor L1 on the power conversion device side is the current flowing through the switching transistor. Excessive ripple current in L1 can lead to increased current stress on the switching transistor, as well as increased inductor losses and switching transistor losses; therefore, it needs to be limited.

[0082] For example, the ripple factor is defined as λ. c_L1 : ;in, This indicates the maximum value of the ripple current. This represents the output current of the alternator. In some embodiments, =0.5.

[0083] Perimeter value of ripple It can be determined using the following formula: ;in, This refers to the ripple current, which is the magnitude of the current fluctuation in a power conversion device during one switching cycle. Indicates the modulation ratio of the power conversion device. This indicates the bus voltage on the energy storage system side. Indicates the switching cycle of the power conversion device. This represents the inductance value of the inductor on the first power conversion device side of the first filter.

[0084] Inductor on the first power conversion device side of the first filter The minimum value is determined in the following way: .in, This indicates the maximum value of the per-unit ripple.

[0085] For example, for sinusoidal pulse width modulation (SPWM) modulation, f in the above equation i(max) It can be represented as:

[0086] ;

[0087] in, Indicates the power conversion device at the switching frequency The maximum value of the first per-unit ripple value. Indicates the power conversion device at the switching frequency The maximum value of the second per-unit ripple value below, Indicates the power conversion device at the switching frequency The maximum value of the third per-unit ripple value below, Indicates the power conversion device at the switching frequency The maximum value of the fourth per-unit ripple value. This represents the modulation ratio of the power conversion device, i.e., the one described above. .

[0088] For example, the output power of the AC generator is 30kW, and the effective value of the output voltage of the AC generator is V. g_rms The voltage is 230Vrms, the DC bus voltage is 750V, the modulation ratio is 0.867, the current I1 is 43.5Arms, the switching frequency is 15kHz, and f i(max) When the ripple factor is 0.2, the minimum value of L1 can be obtained as 0.35. .

[0089] S302. Determine the capacitance range of the capacitors in the first filter based on the output parameters of the AC generator.

[0090] In some embodiments, the output parameters of the alternator may include the output power and the effective value of the output voltage. For example, S302 may include: determining the capacitance range of the capacitor in the first filter based on the output power and the effective value of the output voltage of the alternator. For example, S302 may include: determining the capacitance range of the capacitor in the first filter based on the output power of the alternator, the effective value of the output voltage of the alternator, the fundamental frequency, and the ratio of the reactive power introduced by capacitor C to the rated active power output by the power conversion device.

[0091] The following explains how to determine the capacitance range of capacitor C (also called the filter capacitor) in the first filter: When determining the capacitance range of capacitor C in the first filter, the reactive power introduced by capacitor C needs to be considered. The larger the capacitance of the filter capacitor, the greater the reactive power introduced, and the greater the current flowing through inductor L1 and the switching transistor. The ratio of the reactive power introduced by capacitor C to the rated active power output of the power conversion device is λ. C , λ C The value of is generally 5%, and the capacitance value of capacitor C in the first filter can be within the range of 5%. ;in, This represents the fundamental frequency. For example, the output power of the alternator is 30kW, and the effective value of the output voltage V of the alternator is... g_rms Given a voltage of 230Vrms and a fundamental frequency of 50Hz, substituting these values ​​into the above formula yields the maximum value of the filter capacitor. .

[0092] S303. Determine the inductance range of the AC generator side in the first filter based on the inductance range of the inductor on the first power conversion device side in the first filter, the capacitance range of the capacitor in the first filter, the main harmonic order of the first power conversion device, and the grid-connected current of the first power conversion device.

[0093] The following explains how the inductance range of the alternator-side inductor L2 in the first filter is determined: the transfer function of the inductor current of L2 and the output voltage of the bridge arm. The expression is: ; This is the resonant angular frequency of the LCL filter (i.e., the first filter). . This represents the inductance value of the inductor on the first power conversion device side of the first filter; This represents the capacitance value of the capacitor in the first filter; This represents the inductance value of the alternator-side inductor in the first filter; This represents a complex frequency variable.

[0094] After selecting the inductor L1 and filter capacitor C on the power conversion device side, the inductor L2 is designed according to the harmonic limits in the grid connection standard. Once the system parameters are determined, the phase voltage spectrum of the power conversion device is obtained, from which the main harmonic orders and amplitudes are determined, and thus the following can be obtained: ;

[0095] According to the standard, the grid-connected current is... The harmonic amplitude at (the frequency of the h-th harmonic) accounts for a certain percentage of the rated grid-connected current. proportion to obtain inductance The value is (for harmonic orders greater than 33, (Should be less than 0.3%) .

[0096] For example, the output power of the AC generator is 30kW, and the effective value of the output voltage of the AC generator is V. g_rms The current is 230Vrms, the DC bus voltage is 750V, and the current is... The switching frequency is 15kHz and the value of L1 and C is 300uH and 25uF respectively. λ h If we take 0.15%, then .

[0097] Once the parameter values ​​of L1, L2, and C are determined, these values ​​can be verified. Resonant frequency. The scope of . is controlled within: ; This represents the switching frequency. Assuming the values ​​of L1, C, and L2 are 300uH, 25uF, and 100uH respectively, the resonant frequency is: The switching frequency is 15kHz, which meets the requirements.

[0098] For example, the inductance value of L1 and the capacitance value of C can be the maximum value of the inductance value of L1 and the maximum value of the capacitance value of C.

[0099] S304. The inductance range of the inductor on the first power conversion device side of the first filter, the capacitance range of the capacitor in the first filter, and the inductance range of the inductor on the alternator side of the first filter are determined as the first parameter range of the first filter.

[0100] In this embodiment of the application, the first parameter range of the first filter may include the inductance value range of the inductor on the first power conversion device side of the first filter, the capacitance value range of the capacitor in the first filter, and the inductance value range of the inductor on the alternator side of the first filter.

[0101] In the technical solution provided by the embodiments of this application, the comprehensiveness of the determined first parameter range of the first filter is improved by determining the inductance value range of the inductor on the first power conversion device side of the first filter, the capacitance value range of the capacitor in the first filter, and the inductance value range of the inductor on the alternator side of the first filter.

[0102] Figure 4 A flowchart illustrating a method for determining the range of second parameters of a second filter according to some embodiments, the method comprising:

[0103] S401. Based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, and the switching frequency of the second power conversion device in the first transmission line, determine the inductance range of the inductor on the second power conversion device side of the second filter.

[0104] For example, the ripple factor is defined as λ. c_L1 : or ;in, It is the peak-to-peak value of the ripple current of inductor L1; This represents the output current of the AC generator. 0.5 is the peak-to-peak conversion factor.

[0105] Peak-to-peak value of ripple current in inductor L1 It can be calculated in the following ways: ;in, Where is the switching frequency of the power conversion device, and D is the duty cycle of the photovoltaic generator when generating electricity, which is equal to the ratio of the output voltage of the DC generator to the DC bus voltage; This represents the inductance value of the inductor on the second power conversion device side of the second filter.

[0106] For example, ripple current The effective value can be expressed as: .

[0107] Thus, the range of inductance values ​​for the inductor on the second power conversion device side of the second filter can be: the minimum inductance value for the inductor on the second power conversion device side of the second filter. Value; among which, This is the DC bus voltage. This indicates the maximum output current of the photovoltaic generator.

[0108] The average current I of the capacitor with the largest capacitance value in the second filter of the photovoltaic power generation system. 1_max Given a current of 50A, a ripple factor of 0.4, and a switching frequency of 20kHz, the minimum inductance value of the inductor on the second power conversion device side of the second filter is determined. For example, if the switching frequency is changed to 10kHz, the minimum value of L1 can be obtained as 438uH.

[0109] S402. Determine the capacitance range of the capacitor in the second filter based on the peak-to-peak value of the ripple current of the inductor on the side of the second power conversion device in the second filter, the switching frequency of the second power conversion device in the first transmission line, and the total ripple voltage.

[0110] For example, total ripple voltage It can be determined in the following ways: ;in, This represents the ripple voltage caused by the inductor ripple current charging and discharging the capacitor; It is the peak-to-peak value of the ripple current of the inductor on the second power conversion device side; The switching frequency of the second power conversion device. This is the capacitance value of the capacitor in the second filter.

[0111] Thus, the minimum capacitance value of the capacitor in the second filter can be expressed as: . The value is typically set to 1%.

[0112] For example, with I1_max = 50A, a ripple factor of 0.4, a peak-to-peak ripple current of 10A, a switching frequency of 20kHz, an output voltage of 300V, and a voltage ripple of 1%, the minimum capacitance value of the capacitor in the second filter is... .

[0113] S403. The range of inductance values ​​of the inductor on the second power conversion device side of the second filter and the range of capacitance values ​​of the capacitor in the second filter are determined as the second parameter range of the second filter.

[0114] In this embodiment of the application, the second parameter range of the second filter may include the inductance value range of the inductor on the second power conversion device side of the second filter and the capacitance value range of the capacitor in the second filter.

[0115] In the technical solution provided in this application embodiment, by determining the absolute value of the difference between the first ripple current effective value objective function and the second ripple current effective value objective function as the ripple current difference objective function, it is not necessary to determine the inductance value range of the DC generator side inductor in the second filter, thereby improving the efficiency of determining the second parameter range of the second filter.

[0116] Figure 5 A schematic diagram illustrating the method for determining the target parameter range shared by the first and second filters in some embodiments, such as... Figure 5As shown, based on the operating conditions of the AC-DC converter (including the operating conditions of the circuit between the AC generator and the DC bus), the inductance value range (L1 inductance range, including L) of the inductor on the first power conversion device side of the first filter is determined. 1_ACmax L 1_ACmin The capacitance range of the capacitors in the first filter (C capacitance range, including C) ACmax ) and the inductance range of the alternator-side inductor in the first filter (L2 inductance range, including L 2_ACmin Once these three ranges are determined, they can be verified.

[0117] Based on the operating conditions of the DC-DC converter (the operating conditions of the circuit between the DC generator and the DC bus), determine the inductance range of the inductor on the second power conversion device side of the second filter (L1 inductance range, including L...). 1_DCmin The capacitance range of the capacitors in the second filter (C capacitance range, including C) DCmin Once these two ranges are determined, they can be verified.

[0118] If the above range verification is successful, the target parameter range shared by the first filter and the second filter is determined to include (max{L 1_Acmin ,L 1_DCmin},L 1_ACmax ), (C DCmin, C ACmax ), (L 2_ACmin ,∞).

[0119] Figure 6 A flowchart illustrating a method for determining the objective function of the first ripple current RMS value provided in some embodiments, the method comprising:

[0120] S601. Determine the per-unit value of the ripple current of the first power conversion device in the first transmission line based on the conversion parameters of the first power conversion device in the first transmission line.

[0121] S602. Determine the objective function of the first ripple current value of the first power conversion device in the first transmission line based on the per-unit value of the ripple current of the first power conversion device in the first transmission line, the conversion parameters of the first power conversion device in the first transmission line, the bus voltage on the energy storage system side, and the inductance value of the inductor on the power conversion device side of the first filter.

[0122] S603. Determine the objective function of the effective value of the first ripple current of the first power conversion device in the first transmission line based on the objective function of the first ripple current value of the first power conversion device in the first transmission line.

[0123] For example, ripple current It can be determined in the following ways: ;in, This represents the per-unit value of the ripple current of the first power conversion device.

[0124] It can be determined in the following ways:

[0125] When the modulation ratio m < 2 / 3 The possible values ​​are as follows:

[0126] ;

[0127] When the modulation ratio m ≥ 2 / 3 The possible values ​​are as follows:

[0128] ;

[0129] in, .

[0130] in, .

[0131] The RMS value of the ripple during the switching cycle (i.e., the objective function of the RMS value of the first ripple current of the first power conversion device) can be expressed as: .

[0132] The technical solution provided in this application embodiment can improve the reliability of the objective function of the determined first ripple current effective value of the first power conversion device.

[0133] Figure 7 A flowchart illustrating a method for determining the objective function of the second ripple current RMS value provided in some embodiments, the method comprising:

[0134] S701. Based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, the switching frequency of the first power conversion device in the first transmission line, and the inductance value of the inductor on the second power conversion device side in the second filter, determine the objective function of the second ripple current value of the second power conversion device in the second transmission line.

[0135] S702. Determine the objective function of the effective value of the second ripple current of the second power conversion device in the second transmission line based on the objective function of the second ripple current value of the second power conversion device in the second transmission line.

[0136] In this embodiment of the application, since the DC-DC ripple remains unchanged, the effective value of the ripple during the switching cycle (i.e., the objective function of the effective value of the second ripple current) can be expressed as: .in, .

[0137] The technical solution provided in this application embodiment can improve the reliability of the objective function of the determined effective value of the second ripple current of the second power conversion device.

[0138] Figure 8 A flowchart illustrating the method for determining the target parameters of the first filter and the target parameters of the second filter, provided in some embodiments, is shown below. Figure 8 As shown, the method includes:

[0139] S801. Determine the initial parameters of the first filter and the second filter according to the target parameter range.

[0140] In some embodiments, the initial parameters of the first filter and the initial parameters of the second filter can be randomly selected from the target parameter range.

[0141] S802. Based on the objective function of the total ripple current effective value and the objective function of the ripple current difference, the initial parameters of the first filter and the initial parameters of the second filter are iteratively updated until the iteration condition is met or the number of iterations is equal to the preset number of iterations, so as to obtain the target parameters of the first filter and the target parameters of the second filter.

[0142] Objective function of total ripple current RMS value It can be determined in the following ways .in, , These are the objective functions for the first ripple current RMS value and the second ripple current RMS value, respectively.

[0143] Ripple current difference objective function It can be determined in the following ways .

[0144] In the technical solution provided in this application embodiment, the initial parameters of the first filter and the initial parameters of the second filter are iteratively updated according to the objective function of the total ripple current effective value and the objective function of the ripple current difference until the iteration condition is met or the number of iterations is equal to the preset number of iterations, so as to obtain the target parameters of the first filter and the target parameters of the second filter, thereby improving the reliability of the determined target parameters of the first filter and the target parameters of the second filter.

[0145] Figure 9 A flowchart illustrating the method for determining filter parameters provided in other embodiments, such as... Figure 9 As shown, the method includes the following steps:

[0146] S901, Obtain the target parameter range shared by the first filter and the second filter.

[0147] S902. Determine the initial parameters of the first filter and the second filter according to the target parameter range.

[0148] S903. Determine the objective function for the effective value of the total ripple current and the objective function for the difference in ripple current.

[0149] S904, Objective function for minimizing the RMS value of total ripple current and objective function for minimizing the difference in ripple current.

[0150] S905, Determine the particle update rate of the filter parameters.

[0151] For example, the particle update rate of the filter parameters can be determined based on the objective function of the total ripple current RMS value and the objective function of the ripple current difference. For instance, when the rate of change of the objective functions of the total ripple current RMS value and the objective function of the ripple current difference is low, the particle update rate of the filter parameters is reduced; when the rate of change of the objective functions of the total ripple current RMS value and the objective function of the ripple current difference is high, the particle update rate of the filter parameters is increased.

[0152] S906, Update the filter parameters.

[0153] S907. Under the condition that the iteration conditions are met and the parameter selection range of the filter is satisfied, the target parameters of the first filter and the target parameters of the second filter are obtained.

[0154] Based on the same inventive concept, this application also provides a filter parameter determination apparatus for implementing the filter parameter determination method described above. The solution provided by this apparatus is similar to the implementation described in the above method; therefore, the specific limitations in one or more filter parameter determination apparatus embodiments provided below can be found in the limitations of the filter parameter determination method described above, and will not be repeated here.

[0155] In one exemplary embodiment, Figure 10 A schematic diagram of the structure of a filter parameter determination device provided in some embodiments, such as... Figure 10 As shown, the filter parameter determination device 1000 includes:

[0156] The acquisition module 1001 is used to acquire the first parameter range of the first filter in the first transmission line for transmitting power from the AC generator to the energy storage system, and to acquire the second parameter range of the second filter in the second transmission line for transmitting power from the DC generator to the energy storage system.

[0157] The parameter range determination module 1002 is used to determine the target parameter range shared by the first filter and the second filter based on the first parameter range and the second parameter range.

[0158] The target parameter determination module 1003 is used to obtain the target function of the total ripple current effective value and the target function of the ripple current difference, and to determine the target parameters of the first filter and the target parameters of the second filter based on the target parameter range, the target function of the total ripple current effective value and the target function of the ripple current difference.

[0159] In some embodiments, the acquisition module 1001 includes a first inductance value range determination unit, a first capacitance value range determination unit, a second inductance value range determination unit, and a first parameter range determination unit;

[0160] The first inductance value range determination unit is used to determine the inductance value range of the inductor on the first power conversion device side in the first filter based on the output parameters of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line.

[0161] The first capacitance value range unit is used to determine the capacitance value range of the capacitor in the first filter based on the output parameters of the alternator.

[0162] The second inductance value range determination unit is used to determine the inductance value range of the AC generator side in the first filter based on the inductance value range of the inductor on the first power conversion device side in the first filter, the capacitance value range of the capacitor in the first filter, the main harmonic order of the first power conversion device, and the grid-connected current of the first power conversion device.

[0163] The first parameter range determination unit is used to determine the inductance value range of the inductor on the first power conversion device side of the first filter, the capacitance value range of the capacitor in the first filter, and the inductance value range of the inductor on the alternator side of the first filter as the first parameter range of the first filter.

[0164] In some embodiments, the first inductance value range determining unit is further configured to: determine the output current of the AC generator based on the effective voltage value and power in the output parameters of the AC generator; obtain the maximum value of the per-unit ripple current of the first power conversion device in the first transmission line; and determine the inductance value range of the inductor on the first power conversion device side of the first filter based on the maximum value of the per-unit ripple current of the first power conversion device in the first transmission line, the output current of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line.

[0165] In some embodiments, the acquisition module 1001 includes: a third inductance value range determination unit, a second capacitance value range determination unit, and a second parameter range determination unit;

[0166] The third inductance value range determination unit is used to determine the inductance value range of the inductor on the second power conversion device side of the second filter based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, and the switching frequency of the second power conversion device in the first transmission line.

[0167] The second capacitor value range determination unit is used to determine the capacitance value range of the capacitor in the second filter based on the peak-to-peak value of the ripple current of the inductor on the side of the second power conversion device in the second filter, the switching frequency of the second power conversion device in the first transmission line, and the total ripple voltage.

[0168] The second parameter range determination unit is used to determine the inductance value range of the inductor on the second power conversion device side of the second filter and the capacitance value range of the capacitor in the second filter as the second parameter range of the second filter.

[0169] In some embodiments, the parameter range determination module 1002 includes a ripple current RMS value objective function acquisition unit, a total ripple current RMS value objective function determination unit, and a ripple current difference objective function determination unit.

[0170] The ripple current effective value objective function acquisition unit is used to acquire the first ripple current effective value objective function of the first power conversion device in the first transmission line, and to acquire the second ripple current effective value objective function of the second power conversion device in the second transmission line.

[0171] The objective function for the total ripple current effective value is used to determine the total ripple current effective value objective function by summing the first ripple current effective value objective function and the second ripple current effective value objective function.

[0172] The ripple current difference objective function is used to determine the absolute value of the difference between the first ripple current effective value objective function and the second ripple current effective value objective function.

[0173] In some embodiments, the ripple current RMS objective function acquisition unit is further configured to: determine the per-unit value of the ripple current of the first power conversion device in the first transmission line based on the conversion parameters of the first power conversion device in the first transmission line; determine the first ripple current objective function of the first power conversion device in the first transmission line based on the per-unit value of the ripple current of the first power conversion device in the first transmission line, the conversion parameters of the first power conversion device in the first transmission line, the bus voltage on the energy storage system side, and the inductance value of the inductor on the power conversion device side of the first filter; and determine the first ripple current RMS objective function of the first power conversion device in the first transmission line based on the first ripple current objective function of the first power conversion device in the first transmission line.

[0174] In some embodiments, the ripple current RMS value objective function acquisition unit is further configured to determine the second ripple current value objective function of the second power conversion device in the second transmission line based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, the switching frequency of the first power conversion device in the first transmission line, and the inductance value of the inductor on the second power conversion device side in the second filter; and to determine the second ripple current RMS value objective function of the second power conversion device in the second transmission line based on the second ripple current value objective function of the second power conversion device in the second transmission line.

[0175] In some embodiments, the target parameter determination module 1003 includes an initial parameter determination unit and a target parameter determination unit; the initial parameter determination unit is used to determine the initial parameters of the first filter and the initial parameters of the second filter according to the target parameter range; the target parameter determination unit is used to iteratively update the initial parameters of the first filter and the initial parameters of the second filter according to the target function of the total ripple current effective value and the target function of the ripple current difference, until the iteration condition is met or the number of iterations is equal to the preset number of iterations, so as to obtain the target parameters of the first filter and the target parameters of the second filter.

[0176] The descriptions of the above device embodiments are similar to those of the above method embodiments, and have similar beneficial effects. For technical details not disclosed in the device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0177] Each module in the aforementioned filter parameter determination device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0178] In one exemplary embodiment, Figure 11This is a schematic diagram of the structure of a computer device provided in some embodiments. The computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The input / output interface of the computer device is used for exchanging information between the processor and external devices. The communication interface of the computer device is used for wired or wireless communication with external terminals. Wireless communication can be implemented through Wireless Fidelity (WIFI), mobile cellular networks, Near Field Communication (NFC), or other technologies. When the computer program is executed by the processor, it implements a method for determining filter parameters. The display unit of the computer device is used to form a visually visible image and can be a display screen, a projection device, or a virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0179] Those skilled in the art will understand that Figure 11 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0180] For example, a computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement the steps of the method of any of the above embodiments.

[0181] In one embodiment, a computer-readable storage medium is provided, wherein a computer program, when executed by a processor, implements the steps of the method provided in any of the above embodiments.

[0182] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method provided in any of the above embodiments.

[0183] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the methods described above.

[0184] The processor, functional modules, or functional units in any embodiment of this application may include an integration of one or more of the following: a general-purpose processor, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a central processing unit (CPU), a graphics processing unit (GPU), an embedded neural network processing unit (NPU), a controller, a microcontroller, a microprocessor, a programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, a quantum computing-based data processing logic unit, an artificial intelligence (AI) processor, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0185] The memory or computer-readable storage medium in any embodiment of this application may include at least one of non-volatile memory and volatile memory. Non-volatile memory includes integration of one or more of the following: Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Ferromagnetic Random Access Memory (FRAM), Flash Memory, Magnetic Surface Memory, Optical Disc, Compact Disc Read-Only Memory (CD-ROM), Magnetic Tape, Floppy Disk, Flash Memory, Optical Memory, High-Density Embedded Non-Volatile Memory, Resistive Random Access Memory (ReRAM), Magnetoresistive Random Access Memory (MRAM), Ferroelectric Random Access Memory (FRAM), Phase Change Memory (PCM), Graphene Memory, Volatile Memory, etc. Volatile memory includes one or more of the following: Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0186] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0187] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining filter parameters, characterized in that, The methods include: Obtain the first parameter range of the first filter in the first transmission line from the AC generator to the energy storage system, and obtain the second parameter range of the second filter in the second transmission line from the DC generator to the energy storage system; Based on the first parameter range and the second parameter range, determine the target parameter range shared by the first filter and the second filter; Obtain the objective function for the total ripple current RMS value and the objective function for the ripple current difference, and determine the objective parameters of the first filter and the objective parameters of the second filter based on the objective parameter range, the objective function for the total ripple current RMS value, and the objective function for the ripple current difference.

2. The method according to claim 1, characterized in that, The process of obtaining the first parameter range of the first filter in the first transmission line that transmits power from the AC generator to the energy storage system includes: Based on the output parameters of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line, the inductance value range of the inductor on the first power conversion device side of the first filter is determined. Based on the output parameters of the alternator, determine the capacitance range of the capacitor in the first filter; The inductance range of the inductor on the first power conversion device side of the first filter is determined based on the inductance range of the inductor on the first power conversion device side, the capacitance range of the capacitor in the first filter, the main harmonic order of the first power conversion device, and the grid-connected current of the first power conversion device. The range of inductance values ​​of the inductor on the first power conversion device side of the first filter, the range of capacitance values ​​of the capacitor in the first filter, and the range of inductance values ​​of the inductor on the alternator side of the first filter are determined as the first parameter range of the first filter.

3. The method according to claim 2, characterized in that, The step of determining the inductance range of the inductor on the first power conversion device side of the first filter based on the output parameters of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line includes: The output current of the AC generator is determined based on the effective voltage value and power in the output parameters of the AC generator; Obtain the maximum per-unit value of the ripple current of the first power conversion device in the first transmission line; Based on the maximum per-unit value of the ripple current of the first power conversion device in the first transmission line, the output current of the AC generator, the bus voltage on the energy storage system side, and the conversion parameters of the first power conversion device in the first transmission line, the inductance range of the inductor on the first power conversion device side of the first filter is determined.

4. The method according to any one of claims 1 to 3, characterized in that, The process of obtaining the second parameter range of the second filter in the second transmission line that transmits power from the DC generator to the energy storage system includes: Based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, and the switching frequency of the second power conversion device in the first transmission line, the inductance value range of the inductor on the second power conversion device side of the second filter is determined. The capacitance range of the capacitor in the second filter is determined based on the peak-to-peak value of the ripple current of the inductor on the side of the second power conversion device in the second filter, the switching frequency of the second power conversion device in the first transmission line, and the total ripple voltage. The range of inductance values ​​of the inductor on the second power conversion device side of the second filter and the range of capacitance values ​​of the capacitor in the second filter are determined as the second parameter range of the second filter.

5. The method according to any one of claims 1 to 3, characterized in that, The objective functions for obtaining the effective value of the total ripple current and the objective function for the ripple current difference include: Objective function to obtain the first ripple current effective value of the first power conversion device in the first transmission line, and objective function to obtain the second ripple current effective value of the second power conversion device in the second transmission line; The sum of the objective function for the first effective value of ripple current and the objective function for the second effective value of ripple current is determined as the objective function for the total effective value of ripple current. The absolute value of the difference between the objective function for the first effective value of ripple current and the objective function for the second effective value of ripple current is determined as the objective function for the ripple current difference.

6. The method according to claim 5, characterized in that, The objective function for obtaining the effective value of the first ripple current of the first power conversion device in the first transmission line includes: Based on the transformation parameters of the first power conversion device in the first transmission line, determine the per-unit value of the ripple current of the first power conversion device in the first transmission line; The objective function for the first ripple current value of the first power conversion device in the first transmission line is determined based on the per-unit value of the ripple current of the first power conversion device in the first transmission line, the conversion parameters of the first power conversion device in the first transmission line, the bus voltage on the energy storage system side, and the inductance value of the inductor on the power conversion device side of the first filter. Based on the objective function of the first ripple current value of the first power conversion device in the first transmission line, the objective function of the first ripple current effective value of the first power conversion device in the first transmission line is determined.

7. The method according to claim 5, characterized in that, The objective function for obtaining the effective value of the second ripple current of the second power conversion device in the second transmission line includes: The objective function for the second ripple current value of the second power conversion device in the second transmission line is determined based on the bus voltage on the energy storage system side, the output parameters on the DC generator side, the switching frequency of the first power conversion device in the first transmission line, and the inductance value of the inductor on the second power conversion device side in the second filter. Based on the objective function of the second ripple current value of the second power conversion device in the second transmission line, determine the objective function of the effective value of the second ripple current of the second power conversion device in the second transmission line.

8. The method according to any one of claims 1 to 3, characterized in that, The step of determining the target parameters of the first filter and the target parameters of the second filter based on the target parameter range, the target function of the total ripple current RMS value, and the target function of the ripple current difference includes: Based on the target parameter range, determine the initial parameters of the first filter and the initial parameters of the second filter; Based on the objective function of the total ripple current effective value and the objective function of the ripple current difference, the initial parameters of the first filter and the initial parameters of the second filter are iteratively updated until the iteration condition is met or the number of iterations is equal to the preset number of iterations, so as to obtain the target parameters of the first filter and the target parameters of the second filter.

9. A device for determining filter parameters, characterized in that, The device includes: The acquisition module is used to acquire the first parameter range of the first filter in the first transmission line from the AC generator to the energy storage system, and to acquire the second parameter range of the second filter in the second transmission line from the DC generator to the energy storage system. The parameter range determination module is used to determine the target parameter range shared by the first filter and the second filter based on the first parameter range and the second parameter range; The target parameter determination module is used to obtain the target function of the total ripple current RMS value and the target function of the ripple current difference, and to determine the target parameters of the first filter and the target parameters of the second filter based on the target parameter range, the target function of the total ripple current RMS value and the target function of the ripple current difference.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 8.

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