CN118232395A - Flexible direct current medium-high frequency harmonic suppression device, method, system, equipment and storage medium thereof - Google Patents
Flexible direct current medium-high frequency harmonic suppression device, method, system, equipment and storage medium thereof Download PDFInfo
- Publication number
- CN118232395A CN118232395A CN202410429599.4A CN202410429599A CN118232395A CN 118232395 A CN118232395 A CN 118232395A CN 202410429599 A CN202410429599 A CN 202410429599A CN 118232395 A CN118232395 A CN 118232395A
- Authority
- CN
- China
- Prior art keywords
- converter
- low
- high frequency
- link delay
- direct current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 31
- 238000003860 storage Methods 0.000 title claims abstract description 22
- 230000001629 suppression Effects 0.000 title claims description 28
- 238000013016 damping Methods 0.000 claims abstract description 46
- 230000005540 biological transmission Effects 0.000 claims abstract description 16
- 230000002401 inhibitory effect Effects 0.000 claims abstract description 5
- 238000001914 filtration Methods 0.000 claims description 19
- 238000007634 remodeling Methods 0.000 claims description 16
- 238000004590 computer program Methods 0.000 claims description 15
- 230000010355 oscillation Effects 0.000 abstract description 32
- 238000010586 diagram Methods 0.000 description 23
- 230000004044 response Effects 0.000 description 14
- 230000006870 function Effects 0.000 description 13
- 230000001052 transient effect Effects 0.000 description 10
- 230000001934 delay Effects 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000011217 control strategy Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000006855 networking Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Landscapes
- Inverter Devices (AREA)
Abstract
The invention discloses a device, a method, a system, equipment and a storage medium for suppressing high-frequency harmonic waves in flexible direct current, belonging to the field of flexible direct current transmission, comprising the following steps: the system comprises an inverter, a passive damping device, a low-link delay controller and a first-order low-pass filter; the passive damping device is connected with the alternating current power grid side of the converter and is used for remolding the high-frequency band impedance characteristic in the converter; the low-link delay controller is connected with the current converter and used for rectifying and inverting the current converter to control the current converter; the first-order low-pass filter is connected with the voltage feedforward end of the low-link delay controller and used for inhibiting the input of higher harmonics to the low-link delay controller. The invention can solve the problem of medium-high frequency oscillation in the flexible direct current transmission system.
Description
Technical Field
The invention belongs to the field of flexible direct current transmission, and particularly relates to a flexible direct current medium-high frequency harmonic suppression device, a method, a system, equipment and a storage medium thereof.
Background
The voltage source type converter is core equipment of a flexible direct current transmission technology, is formed by combining modular multilevel converter submodules in a cascading mode, is particularly suitable for high-voltage high-capacity direct current transmission application scenes, has the technical advantages of providing voltage support for an alternating current power grid, having no commutation failure and the like, and is widely studied and applied in recent years.
However, with the continuous construction and the continuous operation of the flexible direct current transmission project, the problem of multiple medium-high frequency harmonic oscillation occurs in the actual project, and huge economic losses are caused, such as the problem of 1.8kHz high frequency oscillation of the Yubei back-to-back networking project, the problem of 2.5kHz high frequency oscillation of the east-sea wind flexible direct delivery project, and the like. Among them, the harmonic stability problem becomes a major problem to be solved. The harmonic stability problem is mainly caused by the fact that the modularized multi-level converter sub-module has complex internal dynamic behaviors, and on-off rectification of components is required to be tracked and controlled according to a voltage signal of 50Hz of power frequency; the actual power system accessed by the flexible direct current transmission equipment is usually complex, contains a certain degree of harmonic components, and influences the control of the control loop after the corresponding harmonic components are introduced into the control loop, so that the problem of high-frequency oscillation of the system is finally caused.
Since the frequency variation in an actual power system is difficult to predict and some variation may occur. It is expected that the method for suppressing harmonic oscillation of a single frequency by a simple control method does not have universality and cannot solve the practical problems encountered in engineering.
Disclosure of Invention
The invention aims to provide a device, a method, a system, equipment and a storage medium for suppressing medium-high frequency harmonic waves in a flexible direct current so as to solve the problem of medium-high frequency oscillation in a flexible direct current transmission system.
In order to achieve the above purpose, the invention adopts the following technical scheme:
A flexible direct current medium and high frequency harmonic suppression device, comprising: the system comprises an inverter, a passive damping device, a low-link delay controller and a first-order low-pass filter;
The passive damping device is connected with the alternating current power grid side of the converter and is used for remolding the high-frequency band impedance characteristic in the converter;
The low-link delay controller is connected with the current converter and used for rectifying and inverting the current converter;
the first-order low-pass filter is connected with the voltage feedforward end of the low-link delay controller and used for inhibiting the input of higher harmonics to the low-link delay controller.
In some embodiments, the passive damping device employs a single-tuned passive damping device having a cutoff frequency above 5 kHz.
In some embodiments, the low link latency controller has a link latency of 200us or less.
In some embodiments, the cut-off frequency of the first order low pass filter is above 1 kHz.
A method for suppressing high-frequency harmonic waves in flexible direct current comprises the following steps:
Link delay of a control loop of the control converter;
performing first-order low-pass filtering at a voltage feedforward end of a control loop of the converter to inhibit transmission of higher harmonics in an alternating current power grid to the control loop;
And carrying out impedance remodeling on the current converter by combining the first-order low-pass filtering, and reshaping the impedance characteristic of the high frequency band in the current converter into positive resistance.
In some embodiments, in the step of controlling a link delay of a control loop of the converter, the link delay is controlled below 200 us.
In some embodiments, in the step of performing first-order low-pass filtering at the voltage feedforward end of the control loop of the converter, a cutoff frequency during the first-order low-pass filtering is set to be above 1 kHz;
in the step of performing impedance remodeling in combination with the first-order low-pass filtering, a cutoff frequency at the time of impedance remodeling is set to be above 5 kHz.
A flexible direct current medium and high frequency harmonic suppression system comprising:
the low link delay control module is used for controlling the link delay of the control loop of the current converter;
The high-order harmonic suppression module is used for performing first-order low-pass filtering on a voltage feedforward end of a control loop of the converter and suppressing transmission of high-order harmonic waves in the alternating current power grid to the control loop;
And the impedance remodeling module is used for conducting impedance remodeling in combination with the higher harmonic suppression module and remolding the impedance characteristics of the high frequency band in the converter into positive resistance.
An electronic device comprising a memory, a processor and a computer program stored in the memory and executable in the processor, the processor implementing the steps of the method for soft dc medium-high frequency harmonic rejection when executing the computer program.
A computer readable storage medium storing a computer program which when executed by a processor implements the steps of the method of flexible dc medium to high frequency harmonic rejection.
Compared with the prior art, the invention has the following beneficial effects:
The invention provides a flexible direct-current medium-high frequency harmonic suppression device which comprises a converter, a passive damping device, a low-link delay controller and a first-order low-pass filter, wherein the converter is connected with the low-link delay controller, the passive damping device is connected to an alternating-current power grid side of the converter, and the first-order low-pass filter is connected to a voltage feedforward end of the low-link delay controller. The invention adopts the low-link delay controller, can adapt to the application requirements of the existing modularized multi-level converter controller, and simultaneously accords with the delay level of the existing flexible direct current transmission engineering controller; and secondly, the first-order low-pass filter is arranged at the voltage feedforward end of the low-link delay controller, so that higher harmonic waves can be prevented from being introduced during direct feedforward, the influence on the transient response speed of the converter can be avoided, and the balance of a harmonic suppression function and transient response characteristics is realized. Finally, the passive damping device is arranged on the alternating current power grid side of the converter, so that the impedance characteristic of the converter in a medium-high frequency band can be remodeled, and the risk of medium-high frequency oscillation of a power system is avoided. In summary, the first-order low-pass filter and the passive damping device are matched, so that the risk of medium-high frequency harmonic oscillation of the converter is avoided on the premise of ensuring the dynamic response speed of the converter, the problem of medium-high frequency oscillation in the flexible direct current transmission system is solved, and the operation stability of the power system is improved.
Furthermore, the invention adopts the single-tuning passive damping device with high cutoff frequency above 5kHz, which can reduce the inductance and capacitance parameters of the passive damping device and reduce the equipment cost and loss.
Furthermore, the invention adopts the high cutoff frequency single-tuning passive damping device with cutoff frequency above 5kHz, the low-link delay controller with link delay below 200us and the first-order low-pass filter with cutoff frequency above 1kHz, thereby being capable of shielding the influence of high-frequency harmonic disturbance on the converter to generate small disturbance characteristics while guaranteeing the dynamic response speed of the converter, realizing the balance of transient and steady-state control characteristics of the converter, thoroughly solving the medium-high frequency harmonic oscillation risk of the converter and improving the running stability of the system.
Drawings
Fig. 1 is a basic topology diagram of a flexible dc medium-high frequency harmonic suppression device according to an embodiment of the present invention;
Fig. 2 is a block diagram of a control of a high frequency band in an inverter of a flexible dc medium-high frequency harmonic suppression device according to an embodiment of the present invention;
fig. 3 is a schematic diagram of impedance characteristics of a converter with different link delays provided by the present invention, in which fig. 3 (a) is a diagram of impedance amplitude of the converter with different link delays, and fig. 3 (b) is a diagram of impedance phase angle of the converter with different link delays;
Fig. 4 is a schematic diagram of impedance characteristics of a converter provided with first-order low-pass filters with different cut-off frequencies according to the present invention, in which fig. 4 (a) is a diagram of impedance amplitude of the converter with first-order low-pass filters with different cut-off frequencies, and fig. 4 (b) is a diagram of impedance phase angle of the converter with first-order low-pass filters with different cut-off frequencies;
Fig. 5 is a schematic diagram of impedance characteristics of a converter matched with a first-order low-pass filter with a cut-off frequency of 2kHz and a passive damping device with different cut-off frequencies, in which fig. 5 (a) is a diagram of impedance amplitude of the converter matched with the first-order low-pass filter with the cut-off frequency of 2kHz and the passive damping device with different cut-off frequencies, and fig. 5 (b) is a diagram of impedance phase angle of the converter matched with the first-order low-pass filter with the cut-off frequency of 2kHz and the passive damping device with different cut-off frequencies;
FIG. 6 is a schematic diagram of a passive damping device according to the present invention;
fig. 7 is a schematic structural diagram of a flexible dc medium-high frequency harmonic suppression system according to the present invention;
FIG. 8 is a schematic flow chart of a method for suppressing high frequency harmonics in a flexible DC power supply according to the present invention;
fig. 9 is a schematic structural diagram of an electronic device according to the present invention.
Detailed Description
In order that those skilled in the art may better understand the present invention, a further detailed description of the technical solution of the present invention will be given below with reference to the accompanying drawings, which are given by way of illustration and not limitation.
It should be noted that the terms "comprises" and "comprising," and any variations thereof, in the description and claims of the present invention are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements that are expressly listed or inherent to such process, method, system, article, or apparatus.
The embodiment of the invention refers to a related control principle of a flexible direct current system in a middle-high frequency band, needs to consider influencing factors influencing the impedance characteristics of the middle-high frequency band to perform parameter setting, and performs verification and design of the impedance characteristics of the middle-high frequency band under different link delays, and specifically comprises the following steps:
as shown in fig. 2, an equivalent control block diagram of the flexible dc system in the middle-high frequency band is shown, and key influencing factors of the converter controller on the impedance characteristics of the middle-high frequency band, such as links of current inner loop, voltage feedforward, link delay, primary loop parameters and the like, are considered. From this, the transfer function of the converter in the mid-high frequency band can be deduced as follows:
In the figure: z m is the high-frequency band impedance transfer function in the converter; l m is an alternating current side equivalent inductance; h if、Hvf and H lf are respectively filtering links of current sampling, voltage sampling and modulated wave output; h i is the inner loop current control gain, H i＝kpi+kii/s; wherein k pi is a proportional adjustment parameter and k ii is an integral adjustment parameter; g dc is the controller link delay; v b is the grid voltage reference value; i b is a power grid current reference value;
as shown in fig. 3, the characteristic curves of the medium-high frequency band impedance of different link delays of the controller of the converter are shown. As can be seen from fig. 3, when the link delay is high, the impedance amplitude and the phase angle of the converter have multiple extreme points, so that an impedance amplitude intersection point is easily formed with the accessed ac system, and the phase angle difference is greater than or equal to 180 degrees, thereby generating oscillation risk.
As shown in fig. 4, the impedance characteristic diagrams of the first-order low-pass filters of the direct voltage feedforward, the voltage feedforward 2kHz cut-off frequency and the voltage feedforward 15.9Hz cut-off frequency are adopted by the controller of the converter at the 150us low link delay. As can be seen from fig. 4, when the cut-off frequency of the first-order low-pass filter is lower, the impedance phase angle of the converter is closer to 90 degrees, but due to the existence of the link delay, the impedance phase angle in the middle-high frequency band can not be smaller than 90 degrees all the time, and still there is a risk of oscillation. Moreover, when the cut-off frequency of the first-order low-pass filter is lower, the phase angle hysteresis of the input and output of the first-order low-pass filter is more, the transient response speed of the converter is slower, and the performance of the converter is greatly influenced; on the other hand, by adopting direct feedforward, higher harmonics are introduced into the controller, so that the converter controller is over-sensitive to high-frequency background harmonics, and the stability of the converter is affected. Therefore, considering the harmonic suppression and transient response characteristics, a first order low pass filter with high cut-off frequency should be used at the voltage feed-forward end of the low link delay controller.
As shown in fig. 5, when a first-order low-pass filter with a cut-off frequency of 2kHz is used for the voltage feedforward end of the low-link delay controller, the impedance characteristic diagrams of the passive damping device with a cut-off frequency of 10kHz and the passive damping device with a cut-off frequency of 2kHz are not arranged on the ac grid side of the inverter. The figure shows that when the passive damping device is configured, the impedance characteristic of the converter can be adjusted in a large range, so that the impedance phase angle of the converter is always within a range of +/-90 degrees, and the risk of medium-high frequency harmonic oscillation with an access system is avoided; on the other hand, when the passive damping device is matched with the first-order low-pass filter of the voltage feedforward end, the inductance and capacitance parameters of the passive damping device can be reduced by adopting the passive damping device with high cutoff frequency, so that the required functions are realized, and the manufacturing cost and the cost of equipment are reduced. Therefore, the invention adds the first-order low-pass filter with high cut-off frequency at the voltage feedforward end of the controller by the mode of matching the voltage feedforward filter and the passive damping device, and configures the passive damping device with high cut-off frequency at the AC power grid side of the converter, thereby directly and accurately improving the AC impedance characteristic of the converter, avoiding the problem that the medium-high frequency harmonic oscillation is difficult to accurately and effectively solve by improving the control strategy, thoroughly solving the risk of the medium-high frequency harmonic oscillation of the converter on the premise of ensuring the dynamic response speed of the converter, reducing the cost of the added primary equipment and improving the running stability of the system.
Example 1
The embodiment provides a flexible direct current medium-high frequency harmonic suppression device, as shown in fig. 1, which comprises a passive damping device arranged at the connection part of a transformer side and an alternating current power grid side of a converter, and a first-order low-pass filter arranged in a controller module;
Specifically, the controller module is a low-link delay controller, a passive damping device is arranged at an alternating current port of the alternating current power grid, the converter is connected with the low-link delay controller, the alternating current power grid outputs alternating current power grid voltage V s to a voltage feedforward end of the low-link delay controller, the alternating current power grid outputs an alternating current power grid side current per unit value I sb to a current inner loop control module of the low-link delay controller, and an inner loop current reference value I ref is arranged for the current inner loop control module, so that accurate current control of the low-link delay controller is realized. The first-order low-pass filter is arranged at the voltage feedforward end of the low-link delay controller and used for inhibiting the input of higher harmonics to the low-link delay controller. The low-link delay controller outputs control voltage V c to the converter, the converter is controlled by rectifying and inverting through a converter valve, and finally the transformer side of the converter is connected with the passive damping device on the side of the alternating current power grid, so that the medium-high frequency band impedance characteristic of the converter can be remolded. In fig. 1, L m is an equivalent inductance on the ac grid side, and the converter provided in this embodiment is a unit of a modular multilevel converter, where a plurality of converters can form the modular multilevel converter;
specifically, the link delay of the low link delay controller is 150us, the cutoff frequency of the first-order low-pass filter is 2kHz, and the passive damping device adopts a single-tuning passive damping device with the cutoff frequency of 10 kHz;
the embodiment also provides a method for suppressing high-frequency harmonic waves in flexible direct current, which comprises the following steps:
The link delay of a control loop of the control converter is 150us; performing first-order low-pass filtering at a voltage feedforward end of a control loop of the converter, setting the cutoff frequency of the first-order low-pass filtering to be 2kHz, and inhibiting higher harmonics in an alternating current power grid from being transmitted to the control loop; and carrying out impedance remodeling on the current converter by combining the first-order low-pass filtering, setting the cutoff frequency at 10kHz during impedance remodeling, and remodeling the impedance characteristic of the high frequency band in the current converter into positive resistance.
With reference to fig. 3, fig. 4 and fig. 5, in this embodiment, the link delay is controlled to 150us, so as to reduce the number of extreme points occurring in the impedance amplitude and phase angle of the converter, and further reduce the situation that the converter and the accessed ac power grid form an impedance amplitude intersection point and the phase angle difference is greater than or equal to 180 degrees, so that the risk of oscillation is avoided; the cutoff frequency of the first-order low-pass filter is set to be 2kHz, so that the impedance phase angle of the converter at the middle and high frequency is larger than 90 degrees, the oscillation risk is reduced, and the transient response speed of the converter can be improved by adopting the first-order low-pass filter with the high cutoff frequency of 2 kHz; the cutoff frequency of the passive damping device is set to 10kHz, and as can be seen from fig. 5, the cutoff frequency is better than the cutoff frequency of 2kHz to reduce the inductance and capacitance parameters of the passive damping device and realize the required functions so as to reduce the equipment cost and the equipment cost. Therefore, the embodiment can directly and accurately improve the alternating current impedance characteristic of the converter by matching the voltage feedforward filter 2kHz cutoff frequency with the passive damping device of the 10kHz cutoff frequency on the basis of 150us low link delay, avoid the problem that the medium-high frequency harmonic oscillation is difficult to accurately and effectively solve only by improving a control strategy, thoroughly solve the medium-high frequency harmonic oscillation risk of the converter on the premise of ensuring the dynamic response speed of the converter, reduce the cost of added primary equipment and improve the operation stability of the system.
The embodiment also provides a flexible direct current medium-high frequency harmonic suppression system, which comprises a low link delay control module, a higher harmonic suppression module and an impedance remolding module, wherein the low link delay control module controls the link delay of a control loop of the converter; the high-order harmonic suppression module performs first-order low-pass filtering on a voltage feedforward end of a control loop of the converter to suppress transmission of high-order harmonic in the alternating current power grid to the control loop; and the impedance remodeling module is combined with the higher harmonic suppression module to perform impedance remodeling, and the impedance characteristics of the high frequency band in the converter are remodeled into positive resistance.
The division of the modules in the embodiments of the present invention is schematically only one logic function division, and there may be another division manner in actual implementation, and in addition, each functional module in each embodiment of the present invention may be integrated in one processor, or may exist separately and physically, or two or more modules may be integrated in one module. The integrated modules may be implemented in hardware or in software functional modules.
There is also provided in this embodiment a computer device including a processor and a memory for storing a computer program including program instructions, the processor for executing the program instructions stored by the computer storage medium. The processor may be a central processing unit (CentralProcessing Unit, CPU), but may also be other general purpose processors, digital signal processors (Digital SignalProcessor, DSP), application SPECIFIC INTEGRATED Circuits (ASIC), off-the-shelf Programmable gate arrays (Field-Programmable GATEARRAY, FPGA) or other Programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., which are the computational core and control core of the terminal, adapted to implement one or more instructions, particularly adapted to load and execute one or more instructions in a computer storage medium to implement a corresponding method flow or corresponding function; the processor provided by the embodiment of the invention can be used for the operation of a flexible direct current medium-high frequency harmonic suppression method.
The present embodiment also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a Memory device in a computer device, for storing programs and data. It is understood that the computer readable storage medium herein may include both built-in storage media in a computer device and extended storage media supported by the computer device. The computer-readable storage medium provides a storage space storing an operating system of the terminal. Also stored in the memory space are one or more instructions, which may be one or more computer programs (including program code), adapted to be loaded and executed by the processor. The computer readable storage medium herein may be a high-speed RAM memory or a non-volatile memory (non-volatile memory), such as at least one magnetic disk memory. One or more instructions stored in a computer-readable storage medium may be loaded and executed by a processor to implement the corresponding steps of the method for high frequency harmonic rejection in flexible direct current in the above embodiments.
When the modularized multi-level converter and the access system generate medium-high frequency harmonic oscillation, an impedance analysis method is generally adopted in engineering to analyze the oscillation risk of the converter and the access system, and a corresponding inhibition method is provided. The criteria are as follows: when the impedance amplitude values of the converter and the access system are equal and the impedance phase angle difference between the converter and the access system is not smaller than 180 degrees, the oscillation risk occurs between the converter and the access system. According to the experience of the existing medium-high frequency harmonic oscillation engineering, in the medium-high frequency band, the impedance phase angle of an alternating current system accessed by the converter is generally of a resistance-capacitance characteristic, and the converter is of an inductive negative resistance characteristic in the frequency band, namely, the impedance phase angle exceeds 90 degrees. Therefore, various types of anti-plastic control methods can be adopted to lower the impedance phase angle of the converter as low as possible to be close to 90 degrees so as to reduce the oscillation risk as much as possible. However, the design and manufacturing level of the existing controller are limited, when the controller link delay is not zero, the inverter impedance cannot be uniformly reduced to below 90 degrees in a wide frequency domain of the medium-high frequency band by adopting the control strategy optimization, so that the problem of harmonic oscillation of the medium-high frequency band cannot be thoroughly avoided.
According to the embodiment, the single-tuning passive damping device and the first-order low-pass filter are matched, so that on the premise that the dynamic response speed of the converter can be guaranteed, the typical impedance characteristic of the converter in the medium-high frequency band is remolded to be positive, the problem of harmonic oscillation or harmonic divergence caused by resonance of the converter and an access system of the converter in the medium-high frequency band is thoroughly solved, the transient steady state characteristic requirement of the converter is met, the loss of the system is reduced, and the reliability and stability of the converter are improved. Specifically, the invention adopts the low-link delay controller, and can adapt to the current application situation of the controller of the existing modularized multi-level converter; secondly, a first-order low-pass filtering link with high cut-off frequency is overlapped in a voltage feedforward link of the low-link delay controller, so that introduction of higher harmonic waves during direct feedforward can be avoided, larger influence on transient response speed of the converter can be avoided, and balance of a harmonic suppression function and transient response characteristics is realized; finally, a passive damping device with high cut-off frequency is arranged on the alternating current power grid side of the converter, so that the impedance characteristic of the converter in a medium-high frequency range can be remodeled, the impedance phase angle of the converter is always within a range of +/-90 degrees, and the risk of medium-high frequency harmonic oscillation caused by the connection of the converter with an access system is avoided. In addition, the passive damping device with high cut-off frequency is adopted, so that inductance and capacitance parameters of the passive damping device can be reduced, and equipment cost and loss are reduced.
Example two
The embodiment provides a flexible direct current medium-high frequency harmonic suppression device, which is different from the device provided in the first embodiment in that the link delay of the low link delay controller is 200us, the cutoff frequency of the first-order low-pass filter is 1kHz, and the passive damping device adopts a single-tuned passive damping device with the cutoff frequency of 5 kHz.
The difference between the method provided by the embodiment one and the method provided by the embodiment one is that the link delay of the control loop for controlling the converter is 200us; setting the cut-off frequency of the first-order low-pass filtering to be 1kHz; setting the cutoff frequency at the time of impedance remodeling to be 5kHz, and remolding the impedance characteristic of a high frequency band in the converter to be positive.
The link delay is controlled to be 200us, the number of extreme points of the impedance amplitude and the phase angle of the converter is reduced, the situation that the converter and the accessed alternating current power grid form an impedance amplitude intersection point and the phase angle difference is larger than or equal to 180 degrees is further reduced, the oscillation risk is avoided, and the delay level of the existing flexible direct current transmission engineering controller is met; the cutoff frequency of the first-order low-pass filter is set to be 1kHz, so that the impedance phase angle of the converter at the middle and high frequency is larger than 90 degrees, the oscillation risk is reduced, and the transient response speed of the converter can be improved by adopting the first-order low-pass filter with the high cutoff frequency of 1 kHz; the cut-off frequency of the passive damping device is set to be 5kHz to reduce inductance and capacitance parameters of the passive damping device and realize required functions so as to reduce equipment manufacturing cost and cost. Therefore, unlike the first embodiment, the present embodiment can improve the ac impedance characteristic of the inverter by reducing the voltage feedforward filter cutoff frequency to 1kHz and the passive damping device of 5kHz cutoff frequency on the basis of 200us low link delay, thereby avoiding the problem that the medium-high frequency harmonic oscillation is difficult to accurately solve by improving the control strategy only, solving the medium-high frequency harmonic oscillation risk of the inverter on the premise of ensuring the dynamic response speed of the inverter, reducing the cost of the added primary equipment, and improving the operation stability of the system.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical aspects of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that: modifications and equivalents may be made to the specific embodiments of the invention without departing from the spirit and scope of the invention, which is intended to be covered by the claims.
Claims (10)
1. A flexible direct current medium-high frequency harmonic suppression device, comprising: the system comprises an inverter, a passive damping device, a low-link delay controller and a first-order low-pass filter;
The passive damping device is connected with the alternating current power grid side of the converter and is used for remolding the high-frequency band impedance characteristic in the converter;
The low-link delay controller is connected with the current converter and used for rectifying and inverting the current converter;
the first-order low-pass filter is connected with the voltage feedforward end of the low-link delay controller and used for inhibiting the input of higher harmonics to the low-link delay controller.
2. A flexible direct current medium and high frequency harmonic suppression device according to claim 1, characterized in that the passive damping device is a single-tuning passive damping device with a cut-off frequency above 5 kHz.
3. The flexible direct current medium-high frequency harmonic suppression device according to claim 1, wherein the low link delay controller has a link delay of 200us or less.
4. A flexible direct current medium and high frequency harmonic suppression device according to claim 1, characterized in that the cut-off frequency of the first order low pass filter is above 1 kHz.
5. The method for suppressing the high-frequency harmonic waves in the flexible direct current is characterized by comprising the following steps of:
Link delay of a control loop of the control converter;
performing first-order low-pass filtering at a voltage feedforward end of a control loop of the converter to inhibit transmission of higher harmonics in an alternating current power grid to the control loop;
And carrying out impedance remodeling on the current converter by combining the first-order low-pass filtering, and reshaping the impedance characteristic of the high frequency band in the current converter into positive resistance.
6. The method of suppressing high frequency harmonics in a flexible dc link according to claim 5, wherein in said step of controlling the link delay of the control loop of the inverter, said link delay is controlled to be 200us or less.
7. The method for suppressing high-frequency harmonics in a flexible direct current according to claim 5, wherein in the step of performing first-order low-pass filtering on a voltage feedforward end of a control loop of the converter, a cutoff frequency at the time of the first-order low-pass filtering is set to be 1kHz or more;
in the step of performing impedance remodeling in combination with the first-order low-pass filtering, a cutoff frequency at the time of impedance remodeling is set to be above 5 kHz.
8. A flexible direct current medium and high frequency harmonic suppression system, comprising:
the low link delay control module is used for controlling the link delay of the control loop of the current converter;
The high-order harmonic suppression module is used for performing first-order low-pass filtering on a voltage feedforward end of a control loop of the converter and suppressing transmission of high-order harmonic waves in the alternating current power grid to the control loop;
And the impedance remodeling module is used for conducting impedance remodeling in combination with the higher harmonic suppression module and remolding the impedance characteristics of the high frequency band in the converter into positive resistance.
9. An electronic device comprising a memory, a processor and a computer program stored in the memory and executable in the processor, the processor implementing the steps of a method of flexible dc medium-high frequency harmonic rejection as claimed in any one of claims 5 to 7 when the computer program is executed by the processor.
10. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program which, when executed by a processor, implements the steps of a method of suppressing high frequency harmonics in a flexible direct current according to any one of claims 5 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410429599.4A CN118232395A (en) | 2024-04-10 | 2024-04-10 | Flexible direct current medium-high frequency harmonic suppression device, method, system, equipment and storage medium thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410429599.4A CN118232395A (en) | 2024-04-10 | 2024-04-10 | Flexible direct current medium-high frequency harmonic suppression device, method, system, equipment and storage medium thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118232395A true CN118232395A (en) | 2024-06-21 |
Family
ID=91504565
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410429599.4A Pending CN118232395A (en) | 2024-04-10 | 2024-04-10 | Flexible direct current medium-high frequency harmonic suppression device, method, system, equipment and storage medium thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118232395A (en) |
-
2024
- 2024-04-10 CN CN202410429599.4A patent/CN118232395A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105915091B (en) | System and method for optimizing active current sharing of parallel power converters | |
| Niroomand et al. | Review and comparison of control methods for uninterruptible power supplies | |
| Liu et al. | Performance comparison of Si IGBT and SiC MOSFET power devices based LCL three‐phase inverter with double closed‐loop control | |
| CN114865633A (en) | Self-adaptive quasi-PR active damping low-frequency harmonic suppression method | |
| Elnady et al. | Operation of parallel inverters in microgrid using new adaptive PI controllers based on least mean fourth technique | |
| Campos-Gaona et al. | Nonminimum phase compensation in VSC-HVDC systems for fast direct voltage control | |
| Khalid et al. | Comparative critical analysis of SAF using soft computing and conventional control techniques for high frequency (400 Hz) aircraft system | |
| WO2023236624A1 (en) | Control method and apparatus for parallel apf | |
| Khefifi et al. | Robust IDA-PBC based load voltage controller for power quality enhancement of standalone microgrids | |
| CN118232395A (en) | Flexible direct current medium-high frequency harmonic suppression device, method, system, equipment and storage medium thereof | |
| Li et al. | Active damping adaptive controller for grid-connected inverter under weak grid | |
| Ayari et al. | Global advanced control strategy for modular multilevel converter integrated in a HVDC link | |
| Sindhu et al. | Three phase auto-tuned shunt hybrid filter for harmonic and reactive power compensation | |
| CN112910283B (en) | Method and system for simultaneously restraining common-mode voltage and circulating current of modular parallel rectifier | |
| CN109149981A (en) | A kind of Multipurpose Optimal Method based on genetic algorithm suitable for MMC | |
| Bouzidi et al. | Virtual flux direct power control of the three-level NPC shunt active power filter based on backstepping control | |
| CN114597975A (en) | Power distribution method and control equipment for parallel system | |
| Jung et al. | A three-phase PWM AC-DC converter with low switching frequency and high power factor using DSP-based repetitive control technique | |
| Benzerafa et al. | Type-1 and type-2 fuzzy logic controller based multilevel DSTATCOM using SVM | |
| CN113690944A (en) | Predictive discrete complex variable resonance control method for inverter | |
| CN113452023A (en) | Harmonic current suppression method and device of flexible direct current converter and storage medium | |
| Hasan et al. | Adaptive modulation index‐based controller for suppression of circulating current in parallel inverters of autonomous microgrid | |
| CN113507205B (en) | Control method, controller and control system for inhibiting MMC common-mode conducted EMI | |
| Helali et al. | Performance study of control strategies applied to smart transformer model based on a five-level cascaded H-bridge rectifier | |
| Tilli et al. | Analysis, dimensioning and robust control of shunt active filter for harmonic currents compensation in electrical mains |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |