Multi-harmonic absorption multiplexing and passive device limit use method of network-forming converter

Abstract

The invention discloses a multi-harmonic absorption multiplexing and passive device limit use method of a network-forming converter. Comprising the following steps: determining a corresponding objective function according to a pre-established passive device loss model under a multi-harmonic absorption multiplexing control architecture of the network-forming converter; the objective function at least comprises a passive device limit use objective function and a harmonic weight objective function; based on the active power and the reactive power obtained through real-time measurement, a preset multi-objective optimization algorithm is used for carrying out iterative solution on a passive device limit use objective function and a harmonic weight objective function, and a target harmonic absorption current instruction is obtained; and based on the target harmonic absorption current instruction, carrying out harmonic absorption multiplexing control on the network-forming converter. The time-varying characteristic of the active working condition of the grid-forming converter is fully utilized, and the extra capacity is reused to absorb power grid harmonics, so that the limit use of passive devices is realized, the utilization rate of the grid-forming converter is improved, the harmonic level of the power grid is reduced, and the electric energy quality of the power grid is improved.

Description

Technical Field

[0001] The present invention relates to the field of grid connection technology, and in particular to a method for maximizing the use of multi-harmonic absorption and multiplexing of a grid-connected converter and its passive components. Background Art

[0002] In the prior art, the active power output condition of the grid-connected converter itself varies with time, and in most operating times, it does not reach the rated value or the maximum value, resulting in a waste of converter capacity. Therefore, effectively reusing the extra capacity of this part of the converter for grid harmonic absorption has high research and practical value.

[0003] However, the remaining capacity of the converter is not a simple algebraic addition or subtraction of kW or kVA as currently understood by the industry. To understand how much capacity the harmonics of a grid-type converter consume, it is necessary to add up the losses of the passive components caused by multiple harmonics and fundamental power to evaluate whether the maximum allowable losses and heat generation have been reached. Under the mixture of multiple harmonic currents, the total loss of the passive components of the grid-type converter is not the sum of the losses calculated for each harmonic separately, and there is a complex coupling relationship between the loss models of each harmonic, which results in the passive components not being fully utilized. Therefore, how to effectively reuse the remaining capacity of the converter for harmonic absorption on a grid-type control architecture while achieving the maximum use of passive components is a problem that needs to be solved. Summary of the invention

[0004] The present invention provides a method for multiplexing multi-harmonic absorption of a meshed converter and limiting the use of its passive components, so as to solve the problem that the remaining capacity of the converter cannot be effectively multiplexed for harmonic absorption in a meshed control architecture and the passive components cannot be fully used.

[0005] According to one aspect of the present invention, a method for absorbing and multiplexing multiple harmonics of a grid-type converter and limiting the use of its passive components is provided, the method comprising:

[0006] According to the passive device loss model under the pre-established multi-harmonic absorption multiplexing control architecture of the grid-type converter, the corresponding objective function is determined; wherein the objective function at least includes: the passive device limit utilization objective function and the harmonic weight objective function; the multi-harmonic absorption multiplexing control architecture of the grid-type converter includes: the basic grid-type control architecture, the current harmonic component calculation module and the harmonic compensation calculation module;

[0007] Based on the real-time measured active power and reactive power, the preset multi-objective optimization algorithm is used to iteratively solve the passive device limit utilization objective function and the harmonic weight objective function to obtain the target harmonic absorption current instruction;

[0008] Harmonic absorption multiplexing control is performed on the grid-connected converter based on the target harmonic absorption current instruction.

[0009] According to another aspect of the present invention, a device for absorbing and multiplexing multiple harmonics of a grid-type converter and limiting the use of its passive components is provided, the device comprising:

[0010] The objective function determination module is used to determine the corresponding objective function according to the pre-established passive device loss model under the multi-harmonic absorption multiplexing control architecture of the grid-type converter; wherein the objective function at least includes: the passive device limit utilization objective function and the harmonic weight objective function; the multi-harmonic absorption multiplexing control architecture of the grid-type converter includes: the basic grid-type control architecture, the current harmonic component calculation module and the harmonic compensation calculation module;

[0011] The instruction solving module is used to iteratively solve the passive device limit utilization objective function and the harmonic weight objective function based on the real-time measured active power and reactive power using a preset multi-objective optimization algorithm to obtain the target harmonic absorption current instruction;

[0012] The harmonic absorption multiplexing control module is used to perform harmonic absorption multiplexing control on the grid-type converter based on the target harmonic absorption current instruction.

[0013] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0014] at least one processor; and

[0015] a memory communicatively connected to the at least one processor; wherein,

[0016] The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for multi-harmonic absorption and multiplexing of a grid-type converter and the limited use of its passive components as described in any embodiment of the present invention.

[0017] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the multi-harmonic absorption multiplexing of a grid-type converter and the method for limiting the use of its passive components as described in any embodiment of the present invention when executed.

[0018] The technical solution of the embodiment of the present invention determines the corresponding passive device maximum utilization objective function and harmonic weight objective function according to the passive device loss model under the pre-established multi-harmonic absorption multiplexing control architecture of the grid-type converter, and then uses the active power and reactive power obtained by real-time measurement under the current working conditions as the input of the preset multi-objective optimization algorithm, iteratively solves the passive device maximum utilization objective function and the harmonic weight objective function to obtain the optimal target harmonic absorption current instruction, and then performs harmonic absorption multiplexing control on the grid-type converter based on the target harmonic absorption current instruction, which solves the problem that the remaining capacity of the converter cannot be effectively reused for harmonic absorption in the grid-type control architecture and the passive devices cannot be fully utilized, and makes full use of the time-varying active working conditions of the grid-type converter, reuses its extra capacity to absorb grid harmonics, so as to achieve the maximum utilization of its passive devices, improves the utilization rate of the grid-type converter, and reduces the grid harmonic level, thereby improving the power quality of the grid.

[0019] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 2 is a schematic diagram of a multi-harmonic absorption multiplexing control architecture of a grid-type converter provided according to Embodiment 1 of the present invention;

[0022] Figure 2 This is a flow chart of a method for absorbing and multiplexing multiple harmonics of a grid-type converter and limiting the use of its passive components according to the first embodiment of the present invention;

[0023] Figure 3 This is a flow chart of a method for multi-harmonic absorption and multiplexing of a grid-type converter and limited use of its passive components provided in accordance with the second embodiment of the present invention;

[0024] Figure 4 This is a flow chart of another method for multi-harmonic absorption and multiplexing of a grid-type converter and limited use of its passive components provided in accordance with the second embodiment of the present invention;

[0025] Figure 5 is a schematic diagram of a circuit model of a capacitor provided according to Embodiment 2 of the present invention;

[0026] Figure 6 is a schematic diagram of the relationship between capacitor equivalent series resistance and frequency according to the second embodiment of the present invention;

[0027] Figure 7 It is a structural schematic diagram of a multi-harmonic absorption multiplexing device of a grid-type converter and a passive device limited use device thereof provided according to the third embodiment of the present invention;

[0028] Figure 8 It is a structural schematic diagram of an electronic device for realizing the multi-harmonic absorption multiplexing of a grid-type converter and the method for limiting the use of its passive components according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] Embodiment 1

[0032] Figure 1 This is a schematic diagram of a multi-harmonic absorption multiplexing control architecture for a grid-type converter provided in the first embodiment of the present invention. Figure 1 As shown, the multi-harmonic absorption multiplexing control architecture of the grid-type converter of this embodiment includes the following two parts:

[0033] (1) Basic network control architecture:

[0034] Based on the basic grid-type control architecture, the voltage u of the filter capacitor connected to the grid can be sampled. c and grid-side current i 2, input to the instantaneous power calculation module to determine the instantaneous active power P output by the converter out and instantaneous reactive power Q out ; Then the instantaneous active power P out and instantaneous reactive power Q out And the given preset active power P set and preset reactive power Q set Input to the power loop, generate a reference voltage amplitude V by simulating the rotor motion and excitation characteristics of the synchronous generator ref and virtual angular frequency ω m , and then by the virtual angular frequency ω m The reference voltage phase θ is obtained by integration ref ; Then the reference voltage amplitude V ref and the reference voltage phase θ ref Input to the voltage command calculation module to obtain the reference voltage command u ref ; Set the reference voltage instruction u ref It is transmitted to the instruction side before the voltage and current dual closed-loop control module as the fundamental reference voltage to achieve basic networking control. Figure 1 In, G u is the transfer function of the voltage outer loop controller, G i is the transfer function of the current inner loop controller.

[0035] (2) Multi-harmonic absorption multiplexing control architecture:

[0036] By taking the sampled grid-side current i 2 The current harmonic component calculation module is sent to calculate the grid-side current harmonic component i gh , and then compare it with the input harmonic absorption current command i ref.h After the difference is made, the harmonic voltage command u is generated in a closed loop through the harmonic compensation calculation module. ref.h ; Then the harmonic voltage command u ref.h With the aforementioned reference voltage command u ref After superposition, voltage and current dual closed-loop control and pulse width modulation (PWM) are performed, the multi-harmonic absorption multiplexing control architecture of the grid-type converter is controlled to realize the multi-harmonic absorption multiplexing of the grid-type converter.

[0037] Based on the above-mentioned grid-type converter multi-harmonic absorption multiplexing control architecture, Figure 2A flowchart of a method for multiple harmonic absorption and multiplexing of a meshed converter and the maximum use of its passive components is provided for the first embodiment of the present invention. This embodiment is applicable to the situation where a meshed converter is used for harmonic absorption multiplexing to achieve the maximum use of its passive components. The method can be performed by a device for multiple harmonic absorption and multiplexing of a meshed converter and the maximum use of its passive components. The device for multiple harmonic absorption and multiplexing of a meshed converter and the maximum use of its passive components can be implemented in the form of hardware and / or software. The device for multiple harmonic absorption and multiplexing of a meshed converter and the maximum use of its passive components can be configured in an electronic device. Figure 2 As shown, the first embodiment provides a method for multiple harmonic absorption and multiplexing of a grid-type converter and limited use of its passive components, which specifically includes the following steps:

[0038] S110. Determine the corresponding objective function according to the pre-established passive device loss model under the multi-harmonic absorption multiplexing control architecture of the grid-type converter; wherein the objective function at least includes: a passive device maximum utilization objective function and a harmonic weight objective function; the multi-harmonic absorption multiplexing control architecture of the grid-type converter includes: a basic grid-type control architecture, a current harmonic component calculation module, and a harmonic compensation calculation module.

[0039] Among them, the passive device may at least include a DC side capacitor of a grid-type converter. The passive device loss model may be constructed based on the loss caused by the fundamental current and low-frequency harmonic current (i.e., harmonic absorption current instruction) on the AC side of the converter on the passive device, and the passive device loss model may at least include: a DC side capacitor loss model of the converter.

[0040] The objective function may refer to a dual optimization objective for characterizing that the loss of passive components of a grid-type converter reaches an upper limit and complies with the weight ratio distribution of each harmonic. The objective function may at least include: a passive component limit utilization objective function and a harmonic weight objective function. Among them, the passive component limit utilization objective function can be used to characterize the loss of passive components of a grid-type converter; the harmonic weight objective function can be used to characterize the weight ratio distribution of each harmonic.

[0041] In the embodiment of the present invention, based on Figure 1 The multi-harmonic absorption multiplexing control architecture of the grid-type converter and passive devices such as the DC side capacitors of the grid-type converter are constructed, and corresponding passive device loss models are established, such as the DC side capacitor loss model of the converter, etc. At the same time, an objective function is established with the passive device loss reaching an upper limit and meeting the weight ratio distribution of each harmonic as the optimization goal, wherein the objective function at least includes: a passive device limit utilization objective function and a harmonic weight objective function.

[0042] S120. Based on the real-time measured active power and reactive power, a preset multi-objective optimization algorithm is used to iteratively solve the passive device limit utilization objective function and the harmonic weight objective function to obtain a target harmonic absorption current instruction.

[0043] Among them, the preset multi-objective optimization algorithm may refer to a pre-configured method for solving optimization problems of multiple objective functions. Exemplarily, the preset multi-objective optimization algorithm may include but is not limited to: particle swarm optimization algorithm, genetic algorithm, differential evolution algorithm and simulated annealing algorithm, etc.

[0044] The target harmonic absorption current instruction may refer to the optimal harmonic absorption current instruction (i.e. Figure 1 i ref.h ), that is, the target harmonic absorption current instruction at this time can meet the dual optimization goals of reaching the upper limit of the passive device loss of the grid-type converter (passive limit) and meeting the weight ratio distribution of each harmonic (multi-harmonic absorption). The harmonic absorption current instruction can include the following information: the amplitude of each harmonic absorption current and the phase of each harmonic absorption current.

[0045] In the embodiment of the present invention, the active power P output by the converter under the multi-harmonic absorption multiplexing control architecture of the grid-type converter can be collected by the grid data collection device. out and reactive power Q out , and then the active power P out and reactive power Q out As the input of the preset multi-objective optimization algorithm, the passive device limit use objective function and the harmonic weight objective function are iteratively solved to obtain the target harmonic absorption current instruction that can meet the dual optimization goals of the passive device loss of the grid-type converter reaching the upper limit (passive limit) and meeting the weight ratio distribution of each harmonic (multi-harmonic absorption). In a specific embodiment, taking the particle swarm optimization algorithm as an example, the passive device limit use objective function and the harmonic weight objective function can be used as the fitness function of the particle swarm optimization algorithm, and the harmonic absorption current instruction to be optimized is used as a particle in the particle swarm, and then the active power and reactive power obtained by real-time measurement and the optimization constraints corresponding to the particle swarm optimization algorithm are used to continuously iterate each particle in the particle swarm, and after the iteration termination condition is met, the final target harmonic absorption current instruction is determined according to the group extreme value (global optimal solution) corresponding to the current particle swarm.

[0046] S130. Perform harmonic absorption multiplexing control on the grid-connected converter based on the target harmonic absorption current instruction.

[0047] In the embodiment of the present invention, after determining the target harmonic absorption current instruction, it is possible to Figure 1The grid-type converter multi-harmonic absorption multiplexing control architecture shown in the figure determines the target harmonic absorption current instruction i ref.h The harmonic component i of the grid-side current gh After the difference is made, the harmonic voltage command u is generated in a closed loop through the harmonic compensation calculation module. ref.h ; Then use the harmonic voltage command u ref.h With reference voltage command u ref The voltage and current dual closed-loop control and PWM modulation are performed to control the grid-type converter to achieve multiple harmonic absorption reuse. Based on the target harmonic absorption current instruction, it can be reused to absorb multiple harmonics of the power grid under the condition of active and reactive power changes of the grid-type converter to achieve the maximum use of its passive components, thereby improving the utilization rate of the grid-type converter and helping to reduce the harmonic level of the power grid.

[0048] The technical solution of the embodiment of the present invention determines the corresponding passive device maximum utilization objective function and harmonic weight objective function according to the passive device loss model under the pre-established multi-harmonic absorption multiplexing control architecture of the grid-type converter, and then uses the active power and reactive power obtained by real-time measurement under the current working conditions as the input of the preset multi-objective optimization algorithm, iteratively solves the passive device maximum utilization objective function and the harmonic weight objective function to obtain the optimal target harmonic absorption current instruction, and then performs harmonic absorption multiplexing control on the grid-type converter based on the target harmonic absorption current instruction, which solves the problem that the remaining capacity of the converter cannot be effectively reused for harmonic absorption in the grid-type control architecture and the passive devices cannot be fully utilized, and makes full use of the time-varying active working conditions of the grid-type converter, reuses its extra capacity to absorb grid harmonics, so as to achieve the maximum utilization of its passive devices, improves the utilization rate of the grid-type converter, and reduces the grid harmonic level, thereby improving the power quality of the grid.

[0049] Embodiment 2

[0050] Figure 3 The flowchart of a method for multiple harmonic absorption and multiplexing of a grid-type converter and its passive device maximum use provided in the second embodiment of the present invention is further optimized and expanded based on the above implementation, and can be combined with various optional technical solutions in the above implementation. Figure 3 As shown, the second embodiment provides a method for multiple harmonic absorption and multiplexing of a grid-type converter and its passive device limiting use, which specifically includes the following steps:

[0051] S210, obtaining a pre-established passive device loss model under a multi-harmonic absorption multiplexing control architecture of a grid-connected converter, and obtaining a pre-configured harmonic weight objective function.

[0052] In the embodiment of the present invention, the data can be obtained from a data storage location such as a local or cloud server. Figure 1 A passive device loss model and a harmonic weight objective function are pre-constructed under the multi-harmonic absorption multiplexing control architecture of the grid-connected converter, wherein the passive devices include at least: a converter DC side capacitor.

[0053] Further, based on the above-mentioned embodiments of the invention, the passive component loss model can be expressed as:

[0054]

[0055] Where P cap is the passive device loss (model), i.e. the total loss of the DC side capacitor of the converter; I C,rms is the total effective value of the current flowing; R ESR is the capacitor equivalent series resistance; f 1 is the fundamental frequency; I C,rms_LOH is the total effective value of low-frequency harmonic current on the DC side of the converter; I C,rms_SHC is the total effective value of high-frequency harmonic current on the DC side of the converter; It indicates the loss caused by low-frequency harmonic components, that is, the loss caused on the capacitor by the effective value of the current on the DC side of the grid-type converter caused by the fundamental current on the AC side plus the low-frequency harmonic current (that is, the harmonic absorption current instruction used for multiple harmonic absorption multiplexing); It represents the loss caused by high-frequency harmonic components, that is, the loss caused by the effective value of the high-frequency switching harmonic current on the DC side of the grid-type converter shaped by the fundamental current on the AC side plus the low-frequency harmonic current (that is, the harmonic absorption current instruction used for multiple harmonic absorption multiplexing).

[0056] Furthermore, the effective value of the total current on the DC side of the converter is C,rms It can be expressed as:

[0057]

[0058] In the formula, is the modulation ratio of the fundamental component in the AC side voltage; k and n are the positive sequence harmonic order and negative sequence harmonic order respectively; is the positive sequence component of the amplitude of the kth harmonic of the AC side harmonic current; is the negative sequence component of the amplitude of the nth harmonic of the AC side harmonic current; is the positive sequence phase angle component of the kth harmonic of the AC side harmonic current; It is the negative sequence phase angle component of the nth harmonic of the AC side harmonic current.

[0059] Furthermore, the total effective value of the low-frequency harmonic current on the DC side of the converter I C,rms_LOH It can be expressed as:

[0060]

[0061] Furthermore, the total effective value of the high-frequency harmonic current on the DC side of the converter is C,rms_SHC It can be expressed as:

[0062]

[0063] Further, based on the above-mentioned embodiments of the invention, the harmonic weight objective function can be expressed as:

[0064]

[0065] Where Q represents the harmonic weight objective function; k represents the harmonic order; h k Indicates the kth harmonic importance weight coefficient; I k Indicates the kth harmonic absorption current amplitude.

[0066] Furthermore, the kth harmonic importance weight coefficient h k It can be expressed as:

[0067]

[0068] In the formula, α j is the sensitivity factor of the jth harmonic.

[0069] S220 : Determine a corresponding passive component limit usage objective function based on a difference between the passive component loss model and a pre-configured passive component limit loss value.

[0070] In the embodiment of the present invention, the corresponding passive component limit usage objective function may be determined based on the passive component loss model obtained above and the preset passive component limit loss value.

[0071] Further, based on the above-mentioned embodiments of the invention, the passive component limit usage objective function can be expressed as follows:

[0072] minδ=|P cap -P capN |;

[0073] Where δ represents the objective function of limiting the use of passive components; P cap Represents passive device loss; P capN Indicates the limit loss value of passive components.

[0074] S230, obtaining the active power and reactive power measured in real time under the multi-harmonic absorption multiplexing control architecture of the grid-type converter, and calling the preset fundamental current calculation formula according to the active power and reactive power to determine the corresponding fundamental current real-time value.

[0075] In the embodiment of the present invention, the active power P of the current working condition under the multi-harmonic absorption multiplexing control architecture of the grid-type converter can be collected by the grid data collection device. out and reactive power Q out , and then determine the active power P by calling the following preset fundamental current calculation formula out and reactive power Q out The corresponding fundamental current real-time value I:

[0076]

[0077] Where U is the three-phase line voltage.

[0078] S240, obtaining optimization constraints and iteration termination conditions corresponding to the particle swarm optimization algorithm.

[0079] The optimization constraint condition may refer to a condition for limiting the solution space corresponding to the objective function (i.e., the harmonic absorption current instruction). The optimization constraint condition in this embodiment may be: the passive device loss value cannot exceed its rated loss, i.e., the passive device loss P cap Cannot exceed the corresponding passive device limit loss value P capN .

[0080] The iteration termination condition may refer to the execution termination condition of the preset particle swarm optimization algorithm, and the iteration termination condition may include: the number of iterations reaches the preset maximum number of iterations, the fitness value deviation between two iterative calculations reaches the preset stop tolerance (that is, the difference between the fitness value of the optimal solution after the previous iteration and the fitness value of the optimal solution after this iteration is less than the preset value), etc.

[0081] In an embodiment of the present invention, the optimization constraint conditions and iteration termination conditions corresponding to the particle swarm optimization algorithm to be called subsequently may be obtained from a data storage location such as a local or cloud server.

[0082] Furthermore, the optimization constraint can be expressed as: stP cap <P capN .

[0083] S250: taking the harmonic absorption current instruction to be solved as a particle in the particle swarm, and initializing the position and speed corresponding to each particle based on the optimization constraint condition.

[0084] In an embodiment of the present invention, a pre-configured particle swarm optimization algorithm can be called, and the harmonic absorption current instruction is used as a particle in the particle swarm, and an initialization operation is performed based on the optimization constraint condition, that is, the initialization setting: population size (number of particles), particle dimension (space dimension of particle search, that is, the dimension of the parameter to be optimized), the position of each particle (a solution to the optimization problem to be solved, that is, a certain harmonic absorption current instruction), speed and individual extreme value (individual optimal solution), preset maximum number of iterations, group extreme value (global optimal solution). Among them, the i-th particle in the particle swarm can be expressed as follows:

[0085]

[0086] In the formula, I i is the i-th harmonic absorption current amplitude; is the i-th harmonic absorption current phase.

[0087] S260, based on the passive device limit utilization objective function, the harmonic weight objective function and the fundamental current real-time value, determine the adaptation value corresponding to each particle.

[0088] In an embodiment of the present invention, the passive device maximum utilization objective function and the harmonic weight objective function can be used as the fitness function of the preset particle swarm optimization algorithm, and then the real-time value of the fundamental current and the amplitude and phase of each harmonic absorption current corresponding to each particle under the current iteration number are substituted into the above fitness function to obtain the fitness value corresponding to each particle in this iteration.

[0089] S270, using the fitness value to update the individual extreme value of the corresponding particle and the group extreme value of the particle group.

[0090] The individual extreme value may refer to the individual optimal solution corresponding to the particle in this iteration, and the group extreme value may refer to the global optimal solution corresponding to the particle group.

[0091] In the embodiment of the present invention, S270 may specifically include:

[0092] If the fitness value of a particle is greater than the fitness value corresponding to the individual extreme value of the particle, the individual extreme value of the particle is updated using the position of the particle in this iteration;

[0093] If the fitness value of a particle is less than the fitness value corresponding to the individual extreme value of the particle, the individual extreme value of the particle is kept unchanged in this iteration;

[0094] If the fitness value of a particle is greater than the fitness value corresponding to the group extreme value of the particle swarm, the group extreme value of the particle swarm is updated using the position of the particle in this iteration;

[0095] If the fitness value of a particle is less than the fitness value corresponding to the group extreme value of the particle swarm, the group extreme value of the particle swarm is kept unchanged in this iteration.

[0096] It should be understood that the position and velocity of the particles in the preset particle swarm optimization algorithm (multi-objective particle swarm optimization algorithm) of this embodiment are still updated according to the method of the single-objective particle swarm optimization algorithm. The difference from the single-objective particle swarm optimization algorithm is that the final result of the single-objective particle swarm optimization algorithm is only one solution, while the final result of the multi-objective particle swarm optimization algorithm is a Pareto optimal solution set composed of a series of Pareto optimal solutions.

[0097] In the preset particle swarm optimization algorithm of this embodiment, the update strategy of the individual extreme value (individual optimal solution) is: when the new solution generated by the particle is dominated by the old solution, the individual extreme value remains unchanged; when the new solution dominates the old solution, the new solution is used as the individual extreme value; and when the new solution and the old solution are not dominant to each other, a solution is randomly selected as the individual extreme value.

[0098] The update strategy of the group extremum (global optimal solution) is: after each iteration, as the particle position is updated, the calculated Pareto optimal solution set will also be updated, and a particle is randomly selected from the updated Pareto solution as the group extremum for the next iteration.

[0099] S280, using the individual extreme value and the group extreme value to update the speed and position of each particle, and update the number of iterations.

[0100] In the embodiment of the present invention, the pre-configured particle speed and position update formula may be called to update the speed and position of each particle, and update the number of iterations.

[0101] Furthermore, the particle velocity and position update formula can be expressed as follows:

[0102]

[0103] In the formula, v ij (t) is the j-th velocity component of the ith particle in the t-th iteration; x ij (t) is the j-th position component of the ith particle in the t-th iteration; ω inertia is the inertia coefficient, which is used to control the influence of the particle's previous velocity on the current velocity, which will affect the particle's global and local search capabilities; c 1 is the individual learning coefficient; c 2 is the global learning coefficient; r 1 and r 2 are two independent random numbers in the interval [0,1]; p ij (t) is the individual extreme value of the ith particle; p gj(t) is the group extreme value of the particle group.

[0104] S290. If the updated number of iterations meets the iteration termination condition, the Pareto optimal solution set corresponding to the current number of iterations is output, and the target harmonic absorption current instruction is determined in the Pareto optimal solution set according to the preset weight coefficients corresponding to the passive device limit utilization objective function and the harmonic weight objective function.

[0105] In an embodiment of the present invention, during the iteration process of the particle swarm optimization algorithm, it can be detected whether the current number of iterations meets the iteration termination condition. If the condition is met, the Pareto optimal solution set corresponding to the current number of iterations is directly output, and based on the preset weight coefficients corresponding to the passive device limit utilization objective function and the harmonic weight objective function, the best global optimal solution is selected from the above Pareto optimal solution set, that is, the final target harmonic absorption current instruction.

[0106] Further, in S290, according to the preset weight coefficients corresponding to the passive component limit utilization objective function and the harmonic weight objective function, a target harmonic absorption current instruction is determined in the Pareto optimal solution set, which specifically includes the following steps:

[0107] A. Determine the first fitness value of the passive device limit utilization objective function corresponding to each Pareto optimal solution in the Pareto optimal solution set, and the second fitness value of the harmonic weight objective function corresponding to each Pareto optimal solution in the Pareto optimal solution set;

[0108] B. For each Pareto optimal solution, determine the first product between the first fitness value and the corresponding first preset weight coefficient, and the second product between the second fitness value and the corresponding second preset weight coefficient, and use the sum of the first product and the second product as the objective function weight value;

[0109] C. Traverse the objective function weight values ​​corresponding to each Pareto optimal solution, and take the corresponding Pareto optimal solution with the largest objective function weight value as the target harmonic absorption current instruction.

[0110] S2100. If the updated number of iterations does not satisfy the iteration termination condition, return to the step of determining the fitness value corresponding to each particle based on the passive device limit utilization objective function, the harmonic weight objective function and the fundamental current real-time value.

[0111] In the embodiment of the present invention, if it is detected that the current iteration situation does not meet the iteration termination condition and does not reach the maximum number of iterations, the process returns to execute the step in S260 to execute the next round of iteration process of the optimization algorithm.

[0112] S2110. Perform harmonic absorption multiplexing control on the grid-connected converter based on the target harmonic absorption current instruction.

[0113] Figure 4 This is a flow chart of another method for absorbing and multiplexing multiple harmonics of a grid-type converter and limiting the use of its passive components provided in the second embodiment of the present invention. Figure 4 As shown, the method mainly includes the following steps:

[0114] 1. Establish a multi-harmonic absorption multiplexing control architecture for grid-type converters;

[0115] 2. Establish a passive device loss model under the condition that the grid-type converter output contains multiple harmonic combinations, where the real-time value of the fundamental current and the absorption current of each harmonic are inputs, and the passive device loss power value is output;

[0116] 3. The real-time value of the fundamental current is calculated based on the active power and reactive power obtained by real-time measurement, and then input into the particle swarm computing module to iteratively solve the harmonic absorption current instruction;

[0117] 4. Each iteration of the particle swarm computing module calculates the loss of the passive components of the grid-type converter through the passive component loss model based on the multiple harmonic current combination input of the current iteration;

[0118] 5. Obtain a combination of multiple harmonic current absorption command values ​​(i.e., target harmonic absorption current command) that reaches the upper limit of the passive device loss of the grid-forming converter and meets the dual optimization goals of the weight ratio distribution of each harmonic through particle swarm iterative calculation;

[0119] 6. Perform harmonic absorption multiplexing control on the converter based on the determined target harmonic absorption current command.

[0120] It should be noted that, in the embodiment of the present invention, under the condition of a larger grid harmonic current distribution, the use of the dynamic surplus capacity of the grid-forming converter to multiplex and absorb grid harmonics is set based on the condition of making up for it as much as possible.

[0121] The technical solution of the embodiment of the present invention determines the corresponding passive device maximum utilization objective function and harmonic weight objective function according to the passive device loss model constructed under the multi-harmonic absorption multiplexing control architecture of the grid-type converter, and then uses the fundamental current real-time value determined under the current working condition and the harmonic absorption current instruction to be solved (each harmonic absorption current) as the input of the particle swarm optimization algorithm. After continuous iterative solution, the optimal target harmonic absorption current instruction is obtained, and then the grid-type converter is subjected to harmonic absorption multiplexing control based on the target harmonic absorption current instruction, which solves the problem that the remaining capacity of the converter cannot be effectively reused for harmonic absorption in the grid-type control architecture, and the passive devices cannot be fully utilized. The time-varying nature of the active working condition of the grid-type converter is fully utilized, and its extra capacity is reused to absorb grid harmonics to achieve the maximum utilization of its passive devices, thereby improving the utilization rate of the grid-type converter and reducing the grid harmonic level, thereby improving the power quality of the grid.

[0122] In order to enable those skilled in the art to better understand the embodiments of the present invention, a specific derivation process of the passive component loss model is given below.

[0123] The passive components of the grid-type converter are mainly DC side capacitors, and the losses of the capacitors during operation mainly include dielectric loss and metal loss. Among them, dielectric loss includes polarization loss and conduction loss caused by dielectric leakage current; metal loss includes loss caused by heating of metal plates and wires and contact resistance between metal plates and wires. The circuit model of the actual capacitor is as follows: Figure 5 As shown, it consists of an equivalent series resistor (ESR), a capacitor (C) and an equivalent series inductor (ESL).

[0124] Therefore, the loss of the capacitor can be expressed as:

[0125] Depend on Figure 6 From the diagram of the relationship between capacitor equivalent series resistance and frequency, it can be seen that when the capacitor ESR is below 1kHz, its resistance decreases with the increase of frequency, and the change range is large; when the frequency is above 1kHz, its resistance remains basically unchanged with the increase of frequency. Therefore, the power loss of the capacitor can be expressed as:

[0126]

[0127] Among them, the first part on the right side of the above formula is the loss caused by the low-frequency harmonic component, and the second part is the loss caused by the high-frequency harmonic component. Among them, the harmonic loss caused by the low-frequency harmonic current on the DC side can be calculated separately using each low-frequency harmonic current of the DC port; the loss caused by the high-frequency harmonic current can be calculated by the total effective value of the high-frequency harmonic current on the DC side.

[0128] According to the basic topological circuit of the grid-type converter, the current expression of the AC side of the grid-type converter can be determined as:

[0129]

[0130] In the formula, ω 1 is the fundamental angular frequency. The first part on the right side of the above equation represents the harmonic current on the AC side, and the second part i sw It means that a series of high-frequency harmonic currents are generated at the AC port by the PWM modulation process. Among them, the high-frequency component of the AC side current can be ignored. By decomposing the positive and negative sequence of the AC side harmonic current, the current expression can be obtained as follows:

[0131]

[0132] In the formula, the superscripts “+” and “-” represent the positive and negative sequence components of the current respectively; k and n are the harmonic orders.

[0133] In any switching cycle, the low-frequency harmonic current i C_LOH The unified mathematical model is:

[0134]

[0135] The analytical expression of low-frequency harmonic current under the mixed output of low-order harmonic current and converter fundamental current is obtained as follows:

[0136]

[0137] The total effective value of the low-frequency harmonic current on the DC side of the grid-type converter is calculated as follows:

[0138]

[0139] The effective value of the total current on the DC side of the grid-connected converter can be expressed as:

[0140]

[0141] Among them, u max 、u med and u min They are respectively expressed as follows:

[0142]

[0143]

[0144] By integrating and simplifying the effective value of the total current on the DC side of the grid-connected converter, it can be obtained that the effective value of the total current on the DC side is divided into five parts:

[0145]

[0146] in,

[0147]

[0148]

[0149] After simplification, the effective value of the total current on the DC side can be expressed as:

[0150]

[0151] By removing the contribution of the effective value of the low-frequency harmonic current from the effective value of the total current on the DC side of the grid-connected converter in the above formula, the effective value of the high-frequency harmonic current on the DC side can be deduced as follows:

[0152]

[0153] In summary, after simplification, the loss of the capacitor is:

[0154]

[0155] Embodiment 3

[0156] Figure 7 This is a schematic diagram of the structure of a multi-harmonic absorption multiplexing device for a grid-type converter and a passive device limiting use device provided in the third embodiment of the present invention. Figure 7 As shown, the device comprises:

[0157] The objective function determination module 31 is used to determine the corresponding objective function according to the pre-established passive device loss model under the multi-harmonic absorption multiplexing control architecture of the grid-type converter; wherein the objective function at least includes: a passive device limit utilization objective function and a harmonic weight objective function; the multi-harmonic absorption multiplexing control architecture of the grid-type converter includes: a basic grid-type control architecture, a current harmonic component calculation module and a harmonic compensation calculation module;

[0158] The instruction solving module 32 is used to iteratively solve the passive device limit utilization objective function and the harmonic weight objective function based on the real-time measured active power and reactive power using a preset multi-objective optimization algorithm to obtain a target harmonic absorption current instruction;

[0159] The harmonic absorption multiplexing control module 33 is used to perform harmonic absorption multiplexing control on the grid-connected converter based on the target harmonic absorption current instruction.

[0160] The technical solution of the embodiment of the present invention determines the corresponding passive device maximum utilization objective function and harmonic weight objective function according to the passive device loss model under the pre-established multi-harmonic absorption multiplexing control architecture of the grid-type converter, and then uses the active power and reactive power obtained by real-time measurement under the current working conditions as the input of the preset multi-objective optimization algorithm, iteratively solves the passive device maximum utilization objective function and the harmonic weight objective function to obtain the optimal target harmonic absorption current instruction, and then performs harmonic absorption multiplexing control on the grid-type converter based on the target harmonic absorption current instruction, which solves the problem that the remaining capacity of the converter cannot be effectively reused for harmonic absorption in the grid-type control architecture and the passive devices cannot be fully utilized, and makes full use of the time-varying active working conditions of the grid-type converter, reuses its extra capacity to absorb grid harmonics, so as to achieve the maximum utilization of its passive devices, improves the utilization rate of the grid-type converter, and reduces the grid harmonic level, thereby improving the power quality of the grid.

[0161] Further, based on the above-mentioned embodiment of the invention, the objective function determination module 31 includes:

[0162] A passive device loss model and harmonic weight objective function acquisition unit is used to acquire a passive device loss model under a pre-established multi-harmonic absorption multiplexing control architecture of a grid-type converter, and to acquire a pre-configured harmonic weight objective function;

[0163] The passive component limit usage objective function determination unit is used to determine the corresponding passive component limit usage objective function based on the difference between the passive component loss model and the pre-configured passive component limit loss value.

[0164] The preset multi-objective optimization algorithm at least includes: a particle swarm optimization algorithm; accordingly, the instruction solving module 32 includes:

[0165] A fundamental current real-time value determination unit is used to obtain the real-time measured active power and reactive power under the multi-harmonic absorption multiplexing control architecture of the grid-type converter, and determine the corresponding fundamental current real-time value by calling a preset fundamental current calculation formula according to the active power and reactive power;

[0166] A condition acquisition unit, used to obtain the optimization constraint conditions and iteration termination conditions corresponding to the particle swarm optimization algorithm;

[0167] An initialization unit, used to use the harmonic absorption current instruction to be solved as a particle in the particle swarm, and initialize the position and speed corresponding to each particle based on the optimization constraint condition;

[0168] A fitness value determination unit, used to determine the fitness value corresponding to each particle based on the passive device limit utilization objective function, the harmonic weight objective function and the fundamental current real-time value;

[0169] An extreme value updating unit, used for updating the individual extreme value of the corresponding particle and the group extreme value of the particle group by using the fitness value;

[0170] An updating unit, used to update the speed and position of each particle using individual extreme values ​​and group extreme values, and to update the number of iterations;

[0171] A first processing unit is configured to output a Pareto optimal solution set corresponding to the current number of iterations if the updated number of iterations satisfies the iteration termination condition, and determine a target harmonic absorption current instruction in the Pareto optimal solution set according to preset weight coefficients corresponding to the passive device limit utilization objective function and the harmonic weight objective function;

[0172] The second processing unit is used to return to the step of determining the fitness value corresponding to each particle based on the passive device limit utilization objective function, the harmonic weight objective function and the fundamental current real-time value if the updated number of iterations does not meet the iteration termination condition.

[0173] Further, based on the above-mentioned embodiments of the invention, according to the preset weight coefficients corresponding to the passive component limit utilization objective function and the harmonic weight objective function, the target harmonic absorption current instruction is determined in the Pareto optimal solution set, including:

[0174] Determine a first fitness value of a passive device limit utilization objective function corresponding to each Pareto optimal solution in the Pareto optimal solution set, and a second fitness value of a harmonic weight objective function corresponding to each Pareto optimal solution in the Pareto optimal solution set;

[0175] For each Pareto optimal solution, determine a first product between the first fitness value and the corresponding first preset weight coefficient, and a second product between the second fitness value and the corresponding second preset weight coefficient, and use the sum of the first product and the second product as the objective function weight value;

[0176] The objective function weight values ​​corresponding to each Pareto optimal solution are traversed, and the corresponding Pareto optimal solution with the largest objective function weight value is taken as the target harmonic absorption current instruction.

[0177] Further, based on the above-mentioned embodiments of the invention, the passive device limit usage objective function is expressed as:

[0178] minδ=|P cap -P capN |;

[0179] Where δ represents the objective function of limiting the use of passive components; P cap Represents passive device loss; P capN Indicates the limit loss value of passive components;

[0180] The harmonic weight objective function is expressed as:

[0181]

[0182] Where Q represents the harmonic weight objective function; k represents the harmonic order; h k Indicates the kth harmonic importance weight coefficient; I k Indicates the kth harmonic absorption current amplitude.

[0183] Further, based on the above-mentioned embodiments of the invention, the passive components at least include: a DC side capacitor of the converter.

[0184] Further, based on the above-mentioned embodiments of the invention, the passive device loss model is expressed as:

[0185]

[0186] Among them, P cap is the total loss of the DC side capacitor of the converter; I C,rms is the total effective value of the current flowing; R ESR is the capacitor equivalent series resistance; f 1 is the fundamental frequency; is the loss caused by low-frequency harmonic components; I C,rms_LOH is the total effective value of low-frequency harmonic current on the DC side of the converter;

[0187] is the loss caused by high-frequency harmonic components; I C,rms_SHC is the total effective value of high-frequency harmonic current on the DC side of the converter.

[0188] The multi-harmonic absorption multiplexing and passive device limited use device of the meshed converter provided in the embodiment of the present invention can execute the multi-harmonic absorption multiplexing and passive device limited use method of the meshed converter provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0189] Embodiment 4

[0190] Figure 8A schematic diagram of the structure of an electronic device 40 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0191] like Figure 8 As shown, the electronic device 40 includes at least one processor 41, and a memory connected to the at least one processor 41, such as a read-only memory (ROM) 42, a random access memory (RAM) 43, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 41 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 42 or the computer program loaded from the storage unit 48 to the random access memory (RAM) 43. In the RAM 43, various programs and data required for the operation of the electronic device 40 can also be stored. The processor 41, the ROM 42, and the RAM 43 are connected to each other through a bus 44. An input / output (I / O) interface 45 is also connected to the bus 44.

[0192] A number of components in the electronic device 40 are connected to the I / O interface 45, including: an input unit 46, such as a keyboard, a mouse, etc.; an output unit 47, such as various types of displays, speakers, etc.; a storage unit 58, such as a disk, an optical disk, etc.; and a communication unit 49, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 49 allows the electronic device 40 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0193] The processor 41 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 41 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The processor 41 executes the various methods and processes described above, such as the multi-harmonic absorption multiplexing of the grid-type converter and the method for limiting the use of its passive components.

[0194] In some embodiments, the multi-harmonic absorption multiplexing of the grid-type converter and the method for limiting the use of its passive components can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 48. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 40 via the ROM 42 and / or the communication unit 49. When the computer program is loaded into the RAM 43 and executed by the processor 41, one or more steps of the multi-harmonic absorption multiplexing of the grid-type converter and the method for limiting the use of its passive components described above can be executed. Alternatively, in other embodiments, the processor 41 can be configured to execute the multi-harmonic absorption multiplexing of the grid-type converter and the method for limiting the use of its passive components by any other appropriate means (for example, by means of firmware).

[0195] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0196] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0197] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0198] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0199] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0200] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0201] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0202] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for absorbing and multiplexing multiple harmonics in a grid-type converter and limiting the use of its passive components, characterized in that: The method comprises: According to the passive device loss model under the pre-established multi-harmonic absorption multiplexing control architecture of the grid-type converter, the corresponding objective function is determined; wherein the objective function at least includes: the passive device limit utilization objective function and the harmonic weight objective function; the multi-harmonic absorption multiplexing control architecture of the grid-type converter includes: a basic grid-type control architecture, a current harmonic component calculation module and a harmonic compensation calculation module; Based on the real-time measured active power and reactive power, a preset multi-objective optimization algorithm is used to iteratively solve the passive device limit utilization objective function and the harmonic weight objective function to obtain a target harmonic absorption current instruction; Harmonic absorption multiplexing control is performed on the grid-connected converter based on the target harmonic absorption current instruction.

2. The method according to claim 1, characterized in that The method of determining the corresponding objective function according to the pre-established passive device loss model under the multi-harmonic absorption multiplexing control architecture of the grid-type converter includes: Obtaining the passive device loss model under the pre-established multi-harmonic absorption multiplexing control architecture of the grid-type converter, and obtaining the pre-configured harmonic weight objective function; Based on the difference between the passive component loss model and the pre-configured passive component limit loss value, the corresponding passive component limit usage objective function is determined.

3. The method according to claim 1, characterized in that The preset multi-objective optimization algorithm at least includes: a particle swarm optimization algorithm; The active power and reactive power obtained by real-time measurement are iteratively solved by using a preset multi-objective optimization algorithm to the passive device limit utilization objective function and the harmonic weight objective function to obtain a target harmonic absorption current instruction, including: The active power and the reactive power measured in real time under the multi-harmonic absorption multiplexing control architecture of the grid-type converter are obtained, and a preset fundamental current calculation formula is called according to the active power and the reactive power to determine the corresponding fundamental current real-time value; Obtaining optimization constraints and iteration termination conditions corresponding to the particle swarm optimization algorithm; The harmonic absorption current instruction to be solved is used as a particle in a particle swarm, and the position and speed corresponding to each particle are initialized based on the optimization constraint condition; Determine the adaptation value corresponding to each of the particles based on the passive device limit utilization objective function, the harmonic weight objective function and the fundamental current real-time value; Using the fitness value to update the individual extreme value of the corresponding particle and the group extreme value of the particle group; Using the individual extreme value and the group extreme value, the speed and position of each particle are updated, and the number of iterations is updated; If the updated number of iterations satisfies the iteration termination condition, the Pareto optimal solution set corresponding to the current number of iterations is output, and the target harmonic absorption current instruction is determined in the Pareto optimal solution set according to the preset weight coefficients corresponding to the passive device limit utilization objective function and the harmonic weight objective function; If the updated number of iterations does not satisfy the iteration termination condition, the step of returning to the step of determining the fitness value corresponding to each particle based on the passive component limit utilization objective function, the harmonic weight objective function and the fundamental current real-time value is executed.

4. The method according to claim 3, characterized in that Determining the target harmonic absorption current instruction in the Pareto optimal solution set according to the preset weight coefficient corresponding to the passive component limit utilization objective function and the harmonic weight objective function includes: Determine a first fitness value of the passive component limit utilization objective function corresponding to each Pareto optimal solution in the Pareto optimal solution set, and a second fitness value corresponding to the harmonic weight objective function; For each of the Pareto optimal solutions, respectively determine a first product between the first fitness value and a corresponding first preset weight coefficient, and a second product between the second fitness value and a corresponding second preset weight coefficient, and use the sum of the first product and the second product as the objective function weight value; The objective function weight values ​​corresponding to each of the Pareto optimal solutions are traversed, and the corresponding Pareto optimal solution with the largest objective function weight value is taken as the target harmonic absorption current instruction.

5. The method according to claim 1, characterized in that The passive device limit usage objective function is expressed as: minδ=|P cap -P capN |; Where δ represents the objective function of limiting the use of passive components; P cap Represents passive device loss; P capN Indicates the limit loss value of passive components; The harmonic weight objective function is expressed as: Where Q represents the harmonic weight objective function; k represents the harmonic order; h k Indicates the kth harmonic importance weight coefficient; I k Indicates the kth harmonic absorption current amplitude.

6. The method according to claim 1, characterized in that The passive components at least include: a DC side capacitor of the converter.

7. The method according to claim 6, characterized in that The passive device loss model is expressed as: Among them, P cap is the total loss of the DC side capacitor of the converter; I C,rms is the total effective value of the current flowing; R ESR is the equivalent series resistance of the capacitor; f1 is the fundamental frequency; is the loss caused by low-frequency harmonic components; I C,rms_LOH is the total effective value of low-frequency harmonic current on the DC side of the converter; is the loss caused by high-frequency harmonic components; I C,rms_SHC is the total effective value of high-frequency harmonic current on the DC side of the converter.

8. A multi-harmonic absorption multiplexing device for a grid-type converter and a device for limiting the use of its passive components, characterized in that: The device comprises: An objective function determination module is used to determine the corresponding objective function according to a pre-established passive device loss model under a multi-harmonic absorption multiplexing control architecture of a meshed converter; wherein the objective function at least includes: a passive device limit utilization objective function and a harmonic weight objective function; the meshed converter multi-harmonic absorption multiplexing control architecture includes: a basic meshed control architecture, a current harmonic component calculation module, and a harmonic compensation calculation module; An instruction solving module is used to iteratively solve the passive device limit utilization objective function and the harmonic weight objective function based on the real-time measured active power and reactive power using a preset multi-objective optimization algorithm to obtain a target harmonic absorption current instruction; The harmonic absorption multiplexing control module is used to perform harmonic absorption multiplexing control on the grid-connected converter based on the target harmonic absorption current instruction.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for multi-harmonic absorption and multiplexing of a grid-type converter and the limited use of its passive components as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the method for multi-harmonic absorption and multiplexing of a grid-type converter and the limited use of its passive components as described in any one of claims 1 to 7 when executed.

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