CN114329980A - Electromechanical transient modeling method and topological structure of modular multilevel matrix converter - Google Patents
Electromechanical transient modeling method and topological structure of modular multilevel matrix converter Download PDFInfo
- Publication number
- CN114329980A CN114329980A CN202111645815.1A CN202111645815A CN114329980A CN 114329980 A CN114329980 A CN 114329980A CN 202111645815 A CN202111645815 A CN 202111645815A CN 114329980 A CN114329980 A CN 114329980A
- Authority
- CN
- China
- Prior art keywords
- power
- frequency side
- low
- converter
- 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
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Landscapes
- Inverter Devices (AREA)
Abstract
The invention discloses an electromechanical transient modeling method and a topological structure of a modular multilevel matrix converter, and belongs to the field of simulation of power systems. The existing simulation modeling scheme mainly focuses on the electromagnetic transient modeling direction, and lacks an electromechanical transient simulation model capable of being practically applied. The electromechanical transient modeling method of the modular multilevel matrix converter is used for equivalent modular multilevel matrix converters by constructing the converter transient simplified model, so that the simplified model which can be used for electromechanical transient simulation programs can be obtained.
Description
Technical Field
The invention relates to an electromechanical transient modeling method and a topological structure of a modular multilevel matrix converter, and belongs to the field of simulation of power systems.
Background
The low-frequency power transmission technology reduces the electric distance by reducing the power transmission frequency, so that the power transmission capacity is improved. Among them, a Modular Multilevel matrix Converter (M3C) has attracted much attention as one of the key devices of the low-frequency power transmission technology, and has important research significance.
Further, chinese patent (publication No. CN109428340B) discloses a simulation method and a topology structure of a flexible dc power transmission apparatus, including: obtaining bridge arm reactance voltage, sub-module capacitors and the number of sub-modules in a bridge arm; simulating the flexible direct-current power transmission device based on the bridge arm reactance, the sub-module capacitor, the number of sub-modules in the bridge arm and a pre-established modular multilevel converter model to obtain electromechanical transient operating characteristics of the flexible direct current and the direct-current power grid under different working conditions; the pre-established modular multilevel converter model is constructed by main circuit parameters, alternating current side equivalent voltage source control quantity and direct current side controllable current source control quantity.
However, the simulation modeling scheme of the scheme and other prior arts mainly focus on the electromagnetic transient modeling direction, and an electromechanical transient simulation model capable of being practically applied is lacking.
Furthermore, the flexible low-frequency power transmission system contains a large number of power electronic devices and controllers, and the low-frequency side and the alternating-current side need to be coupled through a converter, so that the electromechanical transient simulation model of the existing flexible low-frequency power transmission system is very complex, and the engineering calculation accuracy and the engineering calculation efficiency of the electromechanical transient modeling method are further influenced.
Furthermore, in commercial power system analysis software widely applied in China, such as a power system analysis integration program (PSASP), PSD-BPA and the like, no corresponding multi-level modular matrix converter electromechanical transient model exists, and further, related research on the influence of the flexible low-frequency power transmission system on the stability of a power grid is difficult to develop.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an electromechanical transient modeling method and a topological structure of a modular multilevel matrix converter, which are used for equivalent modular multilevel matrix converters by constructing a converter transient simplified model, realize electromechanical transient simulation of the modular multilevel matrix converter, have simple, practical and feasible scheme, and can effectively improve the engineering calculation accuracy and the engineering calculation efficiency of the electromechanical transient modeling method.
In order to achieve the above object, a first technical solution of the present invention is:
an electromechanical transient modeling method of a modular multilevel matrix converter,
constructing a transient simplified model of the converter, wherein the transient simplified model is used for an equivalent modular multilevel matrix converter;
the converter transient state simplified model comprises a power frequency side alternating current power injection model, a low frequency side alternating current power injection model and a bridge arm matrix equivalent model, and electromechanical transient state simulation of the modular multilevel matrix converter is realized;
the power frequency side alternating current power injection model is a power frequency side equivalent mathematical model and is used for determining the relation between a power frequency side alternating current system and an equivalent direct current side;
the low-frequency side alternating current power injection model is a low-frequency side equivalent mathematical model and is used for determining the relation between a low-frequency side alternating current system and an equivalent direct current side;
the bridge arm matrix equivalent model is an equivalent direct current side model and is used for determining the connection relation between the power frequency side model and the low frequency side model.
Through continuous exploration and test, the invention constructs a transient simplified model of the converter, and the transient simplified model is used for an equivalent modular multilevel matrix converter; the transient simplified model of the converter comprises a power frequency side alternating current power injection model, a low frequency side alternating current power injection model and a bridge arm matrix equivalent model, electromechanical transient simulation of the modular multilevel matrix converter is achieved, further the modular multilevel matrix converter can be effectively simplified and modeled, the simplified model which can be used for electromechanical transient simulation programs is obtained, the scheme is simple and practical, the method is practical, and engineering calculation accuracy and engineering calculation efficiency of the electromechanical transient modeling method can be effectively improved.
Furthermore, the invention simplifies and models the modular multilevel matrix converter to obtain a converter transient simplified model which can be used for an electromechanical transient simulation program, fills the blank of the electromechanical transient model of the modular multilevel matrix converter, can be used for planning and safe and stable calculation of a large-scale power grid, provides an important method for the research of a low-frequency power transmission system, and is convenient for programming realization.
As a preferable technical measure:
the method for constructing the power frequency side alternating current power injection model specifically comprises the following steps:
firstly, obtaining an outer loop current control instruction Isdref、Isqref；
The second step, according to the outer ring current control instruction I of the first stepsdref、IsqrefGenerating a power frequency network side current Isd、Isq；
Thirdly, utilizing the power frequency network side current I in the second stepsd、IsqAnd calculating the power frequency alternating current side power, wherein the calculation formula is as follows:
Ps＝|Us|*Isd
Qs＝|Us|*Isq；
wherein, UsThe alternating voltage is the alternating voltage of the power frequency side;
Ps、Qsinjecting active power and reactive power of the modular multilevel matrix converter into a power frequency side alternating current system;
fourthly, calculating the power frequency system alternating-current side power injected into the power frequency side alternating-current system according to the power frequency alternating-current side power in the third step, wherein the calculation formula is as follows:
wherein, UsxIs the X-axis component of the alternating voltage at the power frequency network side;
Usyis the Y-axis component of the alternating voltage at the power frequency network side;
fifthly, the power I of the alternating current side of the power frequency system in the fourth stepsx、IsyAnd injecting the mixed solution into a power frequency side alternating current system.
As a preferable technical measure:
the power frequency side equivalent mathematical model obtains a calculation formula of power frequency side equivalent direct current power according to the principle that the active power injected into the converter at the power frequency alternating current side is equal to the equivalent direct current side power:
in the formula, PdcsIs the power frequency side equivalent DC power, PsActive power, Q, injected into the converter of a line frequency side AC systemsIs the reactive power, P, of the injection converter of the line-frequency side AC systemslossThe equivalent power loss at the power frequency side is obtained, and n% is the total loss coefficient of the modular multilevel matrix converter.
As a preferable technical measure:
the voltage phasor at the injection node of the power frequency side is UsAnd by taking the direction of the injection converter as the positive direction of power, the active power and the reactive power of the injection node respectively satisfy the following formulas:
wherein, Ps、QsInjecting active power and reactive power of a multi-level modular matrix converter into a power frequency side alternating current system;
Isd、Isqfor the AC current at the power frequency side with UsD-axis and Q-axis components of the alternating current determined after DQ decomposition are made for the reference phase.
As a preferable technical measure:
the method for constructing the low-frequency side alternating current power injection model specifically comprises the following steps:
firstly, obtaining an outer loop current control instruction Ildref、Ilqref；
The second step, according to the outer ring current control instruction I of the first stepldref、IlqrefGenerating a low frequency network side current Ild、Ilq；
Thirdly, utilizing the low-frequency network side current I in the second stepld、IlqAnd calculating the low-frequency alternating-current side power, wherein the calculation formula is as follows:
Pl＝|Ul|*Ild
Ql＝|Ul|*Ilq；
wherein, UlAn alternating voltage on the low frequency side;
Pl、Qlinjecting active power and reactive power of the modular multilevel matrix converter into a low-frequency side alternating current system;
fourthly, calculating the low-frequency system alternating-current side power injected into the low-frequency side alternating-current system according to the low-frequency alternating-current side power in the third step, wherein the calculation formula is as follows:
wherein, UlxIs the X-axis component of the low frequency grid side ac voltage;
Ulyis the Y-axis component of the low frequency net side ac voltage;
the fifth step, the fourth stepLow frequency system ac side power Ilx、IlyAnd injecting the mixed solution into a low-frequency side alternating current system.
As a preferable technical measure:
the low-frequency side equivalent mathematical model obtains a calculation formula of the low-frequency side equivalent direct current power according to the principle that the active power of the low-frequency alternating current side injection converter is equal to the equivalent direct current side power:
in the formula, PdclIs low frequency side equivalent DC power, PlActive power, Q, injected into the converter for low frequency side ac systemslIs reactive power, P, of the low frequency side AC system injection converterllossThe equivalent power loss on the low frequency side is n%, and the total loss coefficient of the modular multilevel matrix converter is n%.
As a preferable technical measure:
the injection node on the low frequency side has a voltage phasor of UlAnd by taking the direction of the injection converter as the positive direction of power, the active power and the reactive power of the injection node respectively satisfy the following formulas:
wherein, Pl、QlInjecting active power and reactive power of a multi-level modular matrix converter into a low-frequency side alternating current system;
Ild、Ilqfor low frequency side AC current with UlD-axis and Q-axis components of the alternating current determined after DQ decomposition are made for the reference phase.
As a preferable technical measure:
the equivalent direct current side model comprises a loss coefficient meterCalculating and equivalent capacitance CreqCalculation and power frequency side controlled current source IdcsComputing and low-frequency side controlled current source IdclCalculating and equivalent direct current voltage calculating;
the loss factor calculation includes the following:
according to the power P injected into the power frequency side when considering converter lossessAnd power P injected into the power frequency sidelObtaining a loss coefficient calculation formula of the converter, namely:
wherein n% is the power loss coefficient of the converter;
when the converter loss is not considered, n% is 0, and the injection power amplitudes at the two sides are equal;
the equivalent capacitance calculation includes the following:
because each bridge arm in the modularized multi-level matrix converter is formed by connecting a plurality of sub-modules in series, each sub-module is connected with a direct current capacitor in parallel, and each sub-module capacitor is subjected to series-parallel equivalence according to the topological connection relation to obtain a total equivalent capacitance value CreqThe specific calculation formula is as follows:
wherein, CreqIs an equivalent capacitance value, CiFor the parallel capacitance of each submodule, n1The number of submodules connected in series on a single bridge arm, n2The number of bridge arms of the multi-level modular matrix converter is equal to that of the bridge arms of the multi-level modular matrix converter;
the calculation of the equivalent direct current controlled current of the power and low frequency sides comprises the following contents:
obtaining a controlled current source I according to the power exchange rule of the power frequency side and the low frequency sidedcs、IdclControlled current source Idcs、IdclThe calculation formula of (c) is as follows:
the equivalent direct current voltage calculation comprises the following steps:
according to the circuit structure and the equivalent capacitance of the direct current side, performing circuit calculation on the equivalent direct current side to obtain an equivalent direct current voltage UdcThe calculation formula is as follows:
in order to achieve the above object, a second technical solution of the present invention is:
a multi-level modular matrix converter main circuit topology structure,
the electromechanical transient modeling method applying the modular multilevel matrix converter comprises a power frequency side alternating current system and a low frequency side alternating current system;
the power frequency side alternating current system and the low frequency side alternating current system are electrically connected through a matrix connection structure;
the matrix connection structure is provided with at least 9 bridge arms;
the bridge arm is formed by connecting a plurality of submodules in series.
As a preferable technical measure:
and a power frequency side neutral point O and a low-frequency neutral point N are also arranged.
Compared with the prior art, the invention has the following beneficial effects:
through continuous exploration and test, the invention constructs a transient simplified model of the converter, and the transient simplified model is used for an equivalent modular multilevel matrix converter; the transient simplified model of the converter comprises a power frequency side alternating current power injection model, a low frequency side alternating current power injection model and a bridge arm matrix equivalent model, electromechanical transient simulation of the modular multilevel matrix converter is achieved, further the modular multilevel matrix converter can be effectively simplified and modeled, the simplified model which can be used for electromechanical transient simulation programs is obtained, the scheme is simple and practical, the method is practical, and engineering calculation accuracy and engineering calculation efficiency of the electromechanical transient modeling method can be effectively improved.
Furthermore, the invention simplifies and models the modular multilevel matrix converter to obtain a converter transient simplified model which can be used for an electromechanical transient simulation program, fills the blank of the electromechanical transient model of the modular multilevel matrix converter, can be used for planning and safe and stable calculation of a large-scale power grid, provides an important method for the research of a low-frequency power transmission system, and is convenient for programming realization.
Drawings
FIG. 1 is a schematic flow chart of an electromechanical transient simplified modeling method of the present invention.
FIG. 2 is a simplified model of the transient state of the converter according to the present invention.
Fig. 3 is a schematic view of the topology of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
On the contrary, the invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the present invention, certain specific details are set forth in order to provide a better understanding of the present invention. It will be apparent to one skilled in the art that the present invention may be practiced without these specific details.
As shown in fig. 1, an electromechanical transient modeling method for a modular multilevel matrix converter is to make the modular multilevel matrix converter equivalent to a power frequency side model, a low frequency side model and an equivalent direct current model connecting the two parts, and respectively perform corresponding equivalent modeling on the models, including a power frequency side alternating current power injection model, a low frequency side alternating current power injection model and a bridge arm matrix equivalent model, to form a converter transient simplified model. The equivalent modeling of the bridge arm matrix comprises loss coefficient calculation, equivalent capacitance calculation, establishment of controlled current sources on a power frequency side and a low frequency side, and equivalent direct current voltage calculation.
The invention carries out simplified modeling on the modular multilevel matrix converter (M3C), obtains a simplified model which can be used for an electromechanical transient simulation program, fills the blank of the electromechanical transient model of the modular multilevel matrix converter, can be used for planning and safe and stable calculation of a large-scale power grid, and provides an important method for the research of a low-frequency power transmission system.
As shown in FIG. 2, one embodiment of the transient-reduction model of the converter of the present invention:
the transient state simplified model of the converter is composed of a power frequency side alternating current power injection model, a low frequency side alternating current power injection model and a bridge arm matrix equivalent model, and electromechanical transient state simulation of the modular multilevel matrix converter is achieved.
Wherein: u shapes、UlAlternating voltages at the power frequency side and the low frequency side respectively;
Ps、Qsinjecting active power and reactive power of an M3C converter into a power frequency side alternating current system;
Pl、Qlinjecting active power and reactive power of an M3C converter into a low-frequency side alternating current system;
Isd、Isqperforming DQ decomposition on the alternating current at the power frequency side by taking Us as a reference phase to determine a D-axis component and a Q-axis component of the alternating current;
Ild、Ilqd-axis component and Q-axis component of alternating current determined after DQ decomposition is carried out on the alternating current at the low-frequency side by taking Ul as a reference phase;
Xtsis the reactance value, X, of the line-frequency side converter transformertlThe reactance value of the low frequency side converter transformer.
Pdcs、PdclInjecting direct current power into the M3C converter for the power frequency side and the low frequency side respectively;
Idcs、Idclinjecting equivalent direct current inside M3C converter for power frequency side and low frequency side respectively；
CreqEquivalent capacitance for all bridge arms of M3C;
Udcis the dc voltage across the equivalent capacitor C of M3C.
The invention discloses a specific embodiment of a power frequency side alternating current power injection model, which comprises the following steps:
the power frequency side alternating current power injection model is actually a power frequency side equivalent mathematical model and is used for describing the relation between a power frequency side alternating current system and an equivalent direct current side. Typically, according to the principle that the active power injected into the converter at the power frequency ac side is equal to the power at the equivalent dc side, the following power frequency side power exchange model can be obtained:
in the formula, PsActive power, Q, injected into the converter of a line frequency side AC systemsIs the reactive power, P, of the injection converter of the line-frequency side AC systemslossIs the equivalent power loss of the power frequency side, PdcsThe power frequency side equivalent direct current power is obtained, and n% is the total loss coefficient of the modular multilevel matrix converter.
The voltage phasor at the power frequency side injection node of the M3C circuit topological structure is Us, the direction of the injection converter is the positive direction of power, and the active power and the reactive power of the injection node respectively satisfy the following conditions:
the invention discloses a specific embodiment of a low-frequency side alternating current power injection model, which comprises the following steps:
the low-frequency side alternating current power injection model is actually a low-frequency side equivalent mathematical model and is used for describing the relation between a low-frequency side alternating current system and an equivalent direct current side. Typically, according to the principle that the active power of the low-frequency ac-side injection converter is equal to the equivalent dc-side power, the following low-frequency side power exchange model can be obtained:
in the formula, PlActive power, Q, injected into the converter for low frequency side ac systemslIs reactive power, P, of the low frequency side AC system injection converterllossIs the equivalent power loss on the low frequency side, PdclThe low-frequency side equivalent direct current power is obtained, n% is the total loss coefficient of the modular multilevel matrix converter, and the voltage phasor at the injection node of the low-frequency side is UlAnd the direction of the injection converter is taken as the positive direction of power, and the active power and the reactive power of the injection node respectively meet the following conditions:
the invention relates to a specific embodiment of a bridge arm matrix equivalent model, which comprises the following steps:
the equivalent model of the bridge arm matrix is an equivalent direct current side model, which describes the connection relation between the power frequency side model and the low frequency side model, and comprises loss coefficient calculation and equivalent capacitance CreqCalculating and establishing power frequency side controlled current source IdcsLow frequency side controlled current source IdclAnd calculating the equivalent direct current voltage.
The invention relates to a construction method of an equivalent direct current side model, which comprises the following steps: :
step 301: loss factor calculation
Equivalent models of modular multilevel matrix converters can be divided into two cases, converter loss not considered and converter loss considered. According to the power P injected into the power frequency sidesAnd injection power frequency sidePower P oflThe loss factor of the converter can be obtained, namely:
wherein n% is the converter power loss coefficient. Typically, when the converter losses are not taken into account, n% ═ 0, where the two-sided injection power is equal in magnitude.
Step 302: equivalent capacitance calculation
Each bridge arm in the modularized multi-level matrix converter is formed by connecting a plurality of sub-modules in series, wherein each sub-module is connected with a direct current capacitor in parallel, and each sub-module capacitor is subjected to series-parallel equivalence according to the topological connection relation to obtain a total equivalent capacitance value CreqAs follows:
wherein, CreqIs an equivalent capacitance value, CiFor the parallel capacitance of each submodule, n1The number of submodules connected in series on a single bridge arm, n2The number of the bridge arms is M3C.
Step 303: and calculating the equivalent direct current controlled current of the power and low frequency sides.
According to the power exchange model of the power frequency side and the low frequency side, a controlled current source I can be obtaineddcs、IdclControlled current source Idcs、IdclThe expression of (a) is as follows:
step 304: equivalent DC voltage calculation
According to the circuit structure and the equivalent capacitance of the direct current side, performing circuit calculation on the equivalent direct current side to obtain an equivalent direct current voltage Udc。
As shown in fig. 3, a specific embodiment of a main circuit topology of a multi-level modular matrix converter according to the present invention:
a main circuit topological structure of a multi-level modular matrix converter is characterized in that a matrix formed by 9 bridge arms is connected with a power frequency side alternating current system and a low frequency side alternating current system, and each bridge arm is formed by connecting a plurality of sub-modules in series.
Wherein: u shapesu、Usv、UswThe voltage is the alternating current voltage of the power frequency side;
iu、iv、iwis power frequency side alternating current;
o is a power frequency side neutral point;
Ula、Ulb、Ulcis low-frequency side alternating voltage;
ia、ib、icis low frequency side alternating current;
n is a low-frequency neutral point;
Uua、Uva、Uwa、Uub、Uvb、Uwb、Uuc、Uvc、Uwcthe voltage difference of each bridge arm;
Ucua1、Ucua2……Ucuanthe voltage difference of each submodule in a single bridge arm is obtained;
iua、iva、iwa、iub、ivb、iwb、iuc、ivc、iwcis the current flowing through each bridge arm;
as will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application 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 application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams 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.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (10)
1. A method for electromechanical transient modeling of a modular multilevel matrix converter is characterized in that,
constructing a transient simplified model of the converter, wherein the transient simplified model is used for an equivalent modular multilevel matrix converter;
the converter transient state simplified model comprises a power frequency side alternating current power injection model, a low frequency side alternating current power injection model and a bridge arm matrix equivalent model, and electromechanical transient state simulation of the modular multilevel matrix converter is realized;
the power frequency side alternating current power injection model is a power frequency side equivalent mathematical model and is used for determining the relation between a power frequency side alternating current system and an equivalent direct current side;
the low-frequency side alternating current power injection model is a low-frequency side equivalent mathematical model and is used for determining the relation between a low-frequency side alternating current system and an equivalent direct current side;
the bridge arm matrix equivalent model is an equivalent direct current side model and is used for determining the connection relation between the power frequency side model and the low frequency side model.
2. The method of electromechanical transient modeling of a modular multilevel matrix converter of claim 1,
the method for constructing the power frequency side alternating current power injection model specifically comprises the following steps:
firstly, obtaining an outer loop current control instruction Isdref、Isqref；
The second step, according to the outer ring current control instruction I of the first stepsdref、IsqrefGenerating a power frequency network side current Isd、Isq；
Thirdly, utilizing the power frequency network side current I in the second stepsd、IsqAnd calculating the power frequency alternating current side power, wherein the calculation formula is as follows:
Ps＝|Us|*Isd
Qs＝|Us|*Isq；
wherein, UsThe alternating voltage is the alternating voltage of the power frequency side;
Ps、Qsinjecting active power and reactive power of the modular multilevel matrix converter into a power frequency side alternating current system;
fourthly, calculating the power frequency system alternating-current side power injected into the power frequency side alternating-current system according to the power frequency alternating-current side power in the third step, wherein the calculation formula is as follows:
wherein, UsxIs the X-axis component of the alternating voltage at the power frequency network side;
Usyis the Y-axis component of the alternating voltage at the power frequency network side;
fifthly, the power I of the alternating current side of the power frequency system in the fourth stepsx、IsyAnd injecting the mixed solution into a power frequency side alternating current system.
3. The method of electromechanical transient modeling of a modular multilevel matrix converter of claim 2,
the power frequency side equivalent mathematical model obtains a calculation formula of power frequency side equivalent direct current power according to the principle that the active power injected into the converter at the power frequency alternating current side is equal to the equivalent direct current side power:
in the formula, PdcsIs the power frequency side equivalent DC power, PsActive power, Q, injected into the converter of a line frequency side AC systemsIs the reactive power, P, of the injection converter of the line-frequency side AC systemslossThe equivalent power loss at the power frequency side is obtained, and n% is the total loss coefficient of the modular multilevel matrix converter.
4. The method of electromechanical transient modeling of a modular multilevel matrix converter of claim 2,
the voltage phasor at the injection node of the power frequency side is UsAnd by taking the direction of the injection converter as the positive direction of power, the active power and the reactive power of the injection node respectively satisfy the following formulas:
wherein, Ps、QsInjecting multi-level modules for power frequency side AC systemThe active power and the reactive power of the matrix converter are converted;
Isd、Isqfor the AC current at the power frequency side with UsD-axis and Q-axis components of the alternating current determined after DQ decomposition are made for the reference phase.
5. The method of electromechanical transient modeling of a modular multilevel matrix converter of claim 1,
the method for constructing the low-frequency side alternating current power injection model specifically comprises the following steps:
firstly, obtaining an outer loop current control instruction Ildref、Ilqref；
The second step, according to the outer ring current control instruction I of the first stepldref、IlqrefGenerating a low frequency network side current Ild、Ilq；
Thirdly, utilizing the low-frequency network side current I in the second stepld、IlqAnd calculating the low-frequency alternating-current side power, wherein the calculation formula is as follows:
Pl＝|Ul|*Ild
Ql＝|Ul|*Ilq；
wherein, UlAn alternating voltage on the low frequency side;
Pl、Qlinjecting active power and reactive power of the modular multilevel matrix converter into a low-frequency side alternating current system;
fourthly, calculating the low-frequency system alternating-current side power injected into the low-frequency side alternating-current system according to the low-frequency alternating-current side power in the third step, wherein the calculation formula is as follows:
wherein, UlxIs the X-axis component of the low frequency grid side ac voltage;
Ulyis the Y-axis component of the low frequency net side ac voltage;
the fifth stepThe low-frequency system AC side power I in the fourth steplx、IlyAnd injecting the mixed solution into a low-frequency side alternating current system.
6. The method of electromechanical transient modeling of a modular multilevel matrix converter of claim 5,
the low-frequency side equivalent mathematical model obtains a calculation formula of the low-frequency side equivalent direct current power according to the principle that the active power of the low-frequency alternating current side injection converter is equal to the equivalent direct current side power:
in the formula, PdclIs low frequency side equivalent DC power, PlActive power, Q, injected into the converter for low frequency side ac systemslIs reactive power, P, of the low frequency side AC system injection converterllossThe equivalent power loss on the low frequency side is n%, and the total loss coefficient of the modular multilevel matrix converter is n%.
7. The method of electromechanical transient modeling of a modular multilevel matrix converter of claim 6,
the injection node on the low frequency side has a voltage phasor of UlAnd by taking the direction of the injection converter as the positive direction of power, the active power and the reactive power of the injection node respectively satisfy the following formulas:
wherein, Pl、QlActive power and reactive power of multi-level modular matrix converter for low-frequency side alternating current systemRate;
Ild、Ilqfor low frequency side AC current with UlD-axis and Q-axis components of the alternating current determined after DQ decomposition are made for the reference phase.
8. The method of electromechanical transient modeling of a modular multilevel matrix converter of claim 1,
the equivalent direct current side model comprises loss coefficient calculation and equivalent capacitance CreqCalculation and power frequency side controlled current source IdcsComputing and low-frequency side controlled current source IdclCalculating and equivalent direct current voltage calculating;
the loss factor calculation includes the following:
according to the power P injected into the power frequency side when considering converter lossessAnd power P injected into the power frequency sidelObtaining a loss coefficient calculation formula of the converter, namely:
wherein n% is the power loss coefficient of the converter;
when the converter loss is not considered, n% is 0, and the injection power amplitudes at the two sides are equal;
the equivalent capacitance calculation includes the following:
according to the topological connection relation, each sub-module capacitor is subjected to series-parallel connection equivalence to obtain a total equivalent capacitance value CreqThe specific calculation formula is as follows:
wherein, CreqIs an equivalent capacitance value, CiFor the parallel capacitance of each submodule, n1The number of submodules connected in series on a single bridge arm, n2The number of bridge arms of the multi-level modular matrix converter is equal to that of the bridge arms of the multi-level modular matrix converter;
the calculation of the equivalent direct current controlled current of the power and low frequency sides comprises the following contents:
obtaining a controlled current source I according to the power exchange rule of the power frequency side and the low frequency sidedcs、IdclControlled current source Idcs、IdclThe calculation formula of (c) is as follows:
the equivalent direct current voltage calculation comprises the following steps:
according to the circuit structure and the equivalent capacitance of the direct current side, performing circuit calculation on the equivalent direct current side to obtain an equivalent direct current voltage UdcThe calculation formula is as follows:
9. a multi-level modular matrix converter main circuit topology structure is characterized in that,
the electromechanical transient modeling method using the modular multilevel matrix converter according to any of claims 1 to 8, which includes a power frequency side AC system and a low frequency side AC system;
the power frequency side alternating current system and the low frequency side alternating current system are electrically connected through a matrix connection structure;
the matrix connection structure is provided with at least 9 bridge arms;
the bridge arm is formed by connecting a plurality of submodules in series.
10. The multi-level modular matrix converter main circuit topology of claim 9,
and a power frequency side neutral point O and a low-frequency neutral point N are also arranged.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111645815.1A CN114329980A (en) | 2021-12-30 | 2021-12-30 | Electromechanical transient modeling method and topological structure of modular multilevel matrix converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111645815.1A CN114329980A (en) | 2021-12-30 | 2021-12-30 | Electromechanical transient modeling method and topological structure of modular multilevel matrix converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114329980A true CN114329980A (en) | 2022-04-12 |
Family
ID=81016650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111645815.1A Pending CN114329980A (en) | 2021-12-30 | 2021-12-30 | Electromechanical transient modeling method and topological structure of modular multilevel matrix converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114329980A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116148589A (en) * | 2022-11-15 | 2023-05-23 | 合肥工业大学 | Simplified analysis method and system for fault current of low-frequency power transmission system |
-
2021
- 2021-12-30 CN CN202111645815.1A patent/CN114329980A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116148589A (en) * | 2022-11-15 | 2023-05-23 | 合肥工业大学 | Simplified analysis method and system for fault current of low-frequency power transmission system |
| CN116148589B (en) * | 2022-11-15 | 2023-09-19 | 合肥工业大学 | Simplified analysis method and system for fault current of low-frequency power transmission system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Fu et al. | Control of single-phase grid-connected converters with LCL filters using recurrent neural network and conventional control methods | |
| CN108280271B (en) | Unified power flow controller equivalent modeling method based on switching period average principle | |
| CN103427609B (en) | Harmonic characteristic analytical method of MMC (Modular Multilevel Converter) | |
| CN107123981A (en) | Flexible direct current and direct current network electromechanical transient simulation method and system based on MMC | |
| CN106300426B (en) | The adaptive passivity PI control method of grid-connected inverting system based on MMC | |
| CN111654052B (en) | Flexible direct current converter modeling device and method based on dynamic phasor method | |
| CN107086576B (en) | A kind of Distributed Power Flow controller Multiple Time Scales mathematical model establishing method | |
| Yin et al. | Impedance-based stability analysis and stabilization control strategy of MMC-HVDC considering complete control loops | |
| CN108959671B (en) | Real-time simulation modeling method for half-bridge and full-bridge modular multilevel converter | |
| CN109066784A (en) | A kind of micro-capacitance sensor stability control method based on bifurcation theory | |
| CN114329980A (en) | Electromechanical transient modeling method and topological structure of modular multilevel matrix converter | |
| CN111628495B (en) | Electromagnetic transient simulation method for VSC-MMC (Voltage Source converter-Modular multilevel converter) containing alternating current and direct current grid system | |
| CN104362870B (en) | Control method, device and the rectifier of rectifier | |
| CN105305392A (en) | Symmetrical component method for short circuit calculation of voltage-controlled type IIDG included power distribution network | |
| CN104377721A (en) | VSC-HVDC optimization control method for voltage imbalance of power grid | |
| CN117458877A (en) | DC/DC converter impedance modeling method and system | |
| CN107994581B (en) | Micro-grid harmonic suppression method based on interval optimization algorithm | |
| CN110350531A (en) | The insensitive active filter current control method of a kind of pair of load current ingredient | |
| Cheng et al. | Using Kalman filter to achieve online estimation of equivalent grid impedance and high bandwidth control for LCL-filtered grid-tied inverters | |
| CN108182317B (en) | VSC-based flexible direct current transmission system modeling method | |
| Zabihinejad et al. | Design of direct power controller for a high power neutral point clamped converter using real time simulator | |
| CN107563062A (en) | A kind of AC and DC hybrid transmission system modeling method based on Dynamic Phasors | |
| CN113642179A (en) | Alternating-current impedance modeling method of modular multilevel converter | |
| Subroto et al. | An accurate accelerated steady-state model for high-level modular multilevel converters | |
| CN112307699A (en) | VSC-HVDC electromechanical transient simulation method and system based on phase component |
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 | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20220706 Address after: The eight district of Hangzhou city in Zhejiang province 310014 Huadian Zhaohui under No. 1 Lane Applicant after: STATE GRID ZHEJIANG ELECTRIC POWER COMPANY LIMITED ELECTRIC POWER Research Institute Applicant after: State Grid Zhejiang Electric Power Co., Ltd Address before: The eight district of Hangzhou city in Zhejiang province 310014 Huadian Zhaohui under No. 1 Lane Applicant before: STATE GRID ZHEJIANG ELECTRIC POWER COMPANY LIMITED ELECTRIC POWER Research Institute Applicant before: STATE GRID ZHEJIANG ELECTRIC POWER Co.,Ltd. Applicant before: CHINA ELECTRIC POWER RESEARCH INSTITUTE Co.,Ltd. |