CN114094856A - Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method - Google Patents

Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method Download PDF

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CN114094856A
CN114094856A CN202210052046.2A CN202210052046A CN114094856A CN 114094856 A CN114094856 A CN 114094856A CN 202210052046 A CN202210052046 A CN 202210052046A CN 114094856 A CN114094856 A CN 114094856A
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vector
midpoint potential
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赵志宏
冯义龙
吴佳衡
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Nanjing University of Science and Technology
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/2176—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/14—Arrangements for reducing ripples from dc input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H02M7/064—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode with several outputs
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/06—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
    • H02M7/066—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode particular circuits having a special characteristic

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Abstract

The invention discloses a Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method, which comprises the steps of firstly, providing a novel simplified algorithm to obtain the action time of each basic vector based on the equivalent space vector modulation realized by double carriers; then, by adding a midpoint potential balance compensation factor into the zero-sequence component of the double-carrier modulation, on the basis of adjusting the action time of the positive and negative redundant small vectors to realize midpoint potential balance, a middle vector and a non-redundant small vector are inspected, the influence of the middle vector and the non-redundant small vectors on the midpoint potential is analyzed, the midpoint potential balance compensation factor is optimized, and midpoint potential low-frequency oscillation caused by the middle vector and the non-redundant small vectors is inhibited. The invention provides a modulation method for inhibiting midpoint potential low-frequency oscillation for a Vienna rectifier, effectively solves the problem of midpoint potential low-frequency oscillation, and improves the stability of a system.

Description

Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method
Technical Field
The invention relates to a modulation method for restraining low-frequency oscillation of a midpoint potential of a Vienna rectifier (Vienna rectifier), belonging to the power electronic technology.
Background
The Vienna rectifier is a three-level topology with unidirectional energy transmission, and compared with a three-level Neutral Point Clamped (NPC) topology, the Vienna rectifier has the advantages of simple structure, high power density, no dead zone in a bridge arm, simple driving scheme and the like, so that the Vienna rectifier is widely concerned in the preceding-stage application of electric vehicle charging equipment. However, due to the characteristics of the intrinsic topological structure of the Vienna rectifier, the problems of unbalanced midpoint potential and low-frequency oscillation on the direct current side exist, which will increase the voltage stress of the power switch device and affect the operation life and reliability of the direct current side capacitor.
A large amount of trigonometric function operation is introduced into the traditional space vector modulation, the complexity of a modulation algorithm is increased, meanwhile, the traditional space vector modulation realizes midpoint potential balance by adjusting the action time of positive and negative small vectors, the influence of the middle vectors on the midpoint potential due to uncontrollable control is ignored, and the influence of non-redundant small vectors contained in a two-level space voltage vector distribution diagram corresponding to a large sector on the midpoint potential is also ignored, so that the midpoint potential generates low-frequency oscillation.
Disclosure of Invention
The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides a modulation method for restraining the low-frequency oscillation of the midpoint potential of the Vienna rectifier, which can simply obtain the action time of each basic vector and further analyze the influence of the non-redundant small vector and the non-redundant medium vector which are ignored in the past on the midpoint current.
The technical scheme is as follows: in order to achieve the purpose, the invention adopts the technical scheme that:
a Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method comprises the steps that firstly, a novel simplified algorithm is provided to obtain the action time of each basic vector based on equivalent space vector modulation realized by double carriers; then, by adding a midpoint potential balance compensation factor into the zero-sequence component of the double-carrier modulation, on the basis of adjusting the action time of the positive and negative redundant small vectors to realize midpoint potential balance, a middle vector and a non-redundant small vector are inspected, the influence of the middle vector and the non-redundant small vectors on the midpoint potential is analyzed, the midpoint potential balance compensation factor is optimized, and midpoint potential low-frequency oscillation caused by the middle vector and the non-redundant small vectors is inhibited; the method specifically comprises the following steps:
step 1: determining a space voltage vector distribution diagram according to the conduction state and the current direction of a bidirectional switch tube in the Vienna rectifier topology, performing per unit on the space voltage vector, dividing the space voltage vector distribution diagram into six large sectors, and dividing each large sector into six small sectors;
step 2: determining the action time of the basic vector;
and step 3: and optimizing the midpoint potential balance compensation factor by considering the influence of the medium vector and the non-redundant small vector.
Has the advantages that: compared with the prior art, the Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method provided by the invention has the following advantages: (1) space vector modulation can be directly realized in a three-phase static coordinate system, the step of coordinate transformation is omitted, a large amount of operation is not needed, and the working efficiency is improved; (2) the problem of point potential low-frequency oscillation of the Vienna rectifier caused by medium vectors and non-redundant small vectors is solved.
Drawings
Fig. 1 is a flow chart of a modulation method for suppressing low-frequency oscillation of a midpoint potential of a vienna rectifier by adopting the method of the invention.
Fig. 2 is a three-phase three-level vienna rectifier topology.
Fig. 3 is a space voltage vector distribution diagram.
Fig. 4 is a diagram illustrating an optimal switching sequence of the switching tube.
FIG. 5 shows compensation factors for midpoint potential balancekThe calculation chart of (1).
FIG. 6 is a graph showing experimental comparison of the effects of the conventional modulation method and the modulation method of the present invention: (a) Obtaining capacitance voltage of an upper tube and a lower tube; (b) A comparison graph of midpoint offset voltage between capacitor voltages of an upper tube and a lower tube is shown; (c) Is an input current waveform diagram.
Fig. 7 is an experimental result on a modulation waveform obtained using the parameters of fig. 6: (a) Experimental results for implementing the conventional modulation method; (b) For carrying out the process of the inventionAnd (5) experimental results.
FIG. 8 is an experimental result on a midpoint current waveform using the parameters of FIG. 6: (a) Experimental results for implementing the conventional modulation method; (b) Experimental results for carrying out the method of the invention.
Detailed Description
The invention is described in detail below with reference to the figures and the embodiments.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
As shown in fig. 1, a flowchart of a modulation method for suppressing low-frequency oscillation of a midpoint potential of a vienna rectifier is shown, and first, a novel simplified algorithm is provided to obtain an action time of each basic vector based on equivalent space vector modulation realized by double carriers; then, by adding a midpoint potential balance compensation factor into the zero-sequence component of the double-carrier modulation, on the basis of adjusting the action time of the positive and negative redundant small vectors to realize midpoint potential balance, a middle vector and a non-redundant small vector are inspected, the influence of the middle vector and the non-redundant small vectors on the midpoint potential is analyzed, the midpoint potential balance compensation factor is optimized, and midpoint potential low-frequency oscillation caused by the middle vector and the non-redundant small vectors is inhibited. The method mainly comprises three steps.
The method comprises the following steps: the space voltage vector is unified, the space voltage vector distribution diagram is divided into six large sectors, and each large sector is divided into six small sectors.
FIG. 2 shows a three-phase three-level Vienna rectifier topology, wherein the Vienna rectifier operates stablyTerminal voltage of time
Figure 907223DEST_PATH_IMAGE001
Is determined by the direction of the input current and the switching state of the power switch tube, and exists
Figure 89943DEST_PATH_IMAGE002
Three different values. The neutral potential being balanced in the ideal state, i.e.
Figure 135259DEST_PATH_IMAGE003
All voltages thereon areV dc V 2, so the voltage of the Vienna rectifier input point relative to the DC side capacitor midpoint in FIG. 2
Figure 936993DEST_PATH_IMAGE004
Are all 0 ±V dc /2 three different values, and the switching function
Figure 16944DEST_PATH_IMAGE005
The relationship of (1) is:
Figure 104986DEST_PATH_IMAGE006
neutral pointN Relative to the DC side capacitance midpointOVoltage ofV ON Comprises the following steps:
Figure 27812DEST_PATH_IMAGE007
the input voltage per current-intersecting side of the Vienna rectifier is a function of the switchingS K The expression of (a) is:
Figure 492291DEST_PATH_IMAGE008
the space voltage vector is defined as:
Figure 426749DEST_PATH_IMAGE009
fig. 3 is a space voltage vector distribution diagram, in which there are only 4 space voltage vectors with different lengths, and there are 19 different vectors, which are: 1 zero vector with a modular length of 0; 6 large vectors with a modular length of 2V dc A/3; 6 medium vectors with a modular length of
Figure 561058DEST_PATH_IMAGE010
(ii) a 6 small vectors with a modular length ofV dc /3. Let modulation ratio
Figure 580967DEST_PATH_IMAGE011
And growing each vector modulo atV dc Per 2, then the large vector has a modular length of 4/3, and the medium vector has a modular length of 4/3
Figure 583558DEST_PATH_IMAGE012
The small vector has a modulo length of 2/3 and the zero vector has a modulo length of 0.
Then, dividing large sectors according to voltage intervals:
Figure 765665DEST_PATH_IMAGE013
is the region ofIThe size of the large sector is such that,
Figure 461089DEST_PATH_IMAGE014
is the region ofIIThe size of the large sector is such that,
Figure 968293DEST_PATH_IMAGE015
is the region ofIIIThe size of the large sector is such that,
Figure 649941DEST_PATH_IMAGE016
is the region ofIVThe size of the large sector is such that,
Figure 558992DEST_PATH_IMAGE017
is the region ofVThe size of the large sector is such that,
Figure 159737DEST_PATH_IMAGE018
is the region ofVIA large sector.
Desired synthesized target vectorV ref The starting point of (a) is not at the midpoint of the two-level regular hexagon, so that the two-level SVPWM modulation method cannot be used. In order to solve the above problem, the starting point of the target vector to be synthesized may be translated and coordinate correction may be performed, that is, the small vector corresponding to the large sector is subtracted from the target vector as follows:
Figure 154238DEST_PATH_IMAGE019
wherein:V ref the target vector is represented by a vector of interest,
Figure 623266DEST_PATH_IMAGE020
which represents the target vector after the correction,
Figure 386822DEST_PATH_IMAGE020
the components in the three-phase stationary coordinate system are respectively
Figure 424048DEST_PATH_IMAGE021
；V j0A small vector representing the large sector to which the target vector corresponds,
Figure 781211DEST_PATH_IMAGE022
indicating the number of the large sector.
Under different large sectors as shown in the above formulaV j0The coordinates are shown in table 1.
TABLE 1 under different large sectorsV j0Coordinates of the object
Large fanZone numbering V 0ja V 0jb V 0jc
I 2/3 -1/3 -1/3
II 1/3 1/3 -2/3
III -1/3 2/3 -1/3
IV -2/3 1/3 1/3
V -1/3 -1/3 2/3
VI 1/3 -2/3 1/3
The target vector is located atILarge sector ofiAnd the small sector firstly judges the conditions under the alpha beta coordinate:
Figure 929296DEST_PATH_IMAGE023
the three-phase variable which is converted into the three-phase static coordinate system satisfies the following relational expression:
Figure 547359DEST_PATH_IMAGE024
similar to the above equation, the three-phase relationship of other small sectors can be respectively derived, and when the target vector is located in different small sectors of different large sectors, the three-phase relationship is written into a uniform expression form:
Figure 489907DEST_PATH_IMAGE025
wherein:
Figure 583634DEST_PATH_IMAGE026
，
Figure 4251DEST_PATH_IMAGE027
respectively are the unified correction components of the corrected target vector under the three-phase static coordinate system.
In combination with the above equation, the small sectors may be divided:
Figure 7979DEST_PATH_IMAGE028
is the region ofiThe size of the small sector is such that,
Figure 387008DEST_PATH_IMAGE029
is the region ofiiThe size of the small sector is such that,
Figure 453184DEST_PATH_IMAGE030
is the region ofivThe size of the small sector is such that,
Figure 208651DEST_PATH_IMAGE031
is the region ofvThe size of the small sector is such that,
Figure 535727DEST_PATH_IMAGE032
is the region ofviA small sector.
Step two: the action time of the basis vector is determined.
When the target vectorV ref Is located at the firstiWhen the cell sector is in, a seven-segment vector synthesis mode is adopted, zero vectors of two levels respectively correspond to positive small vectors and negative small vectors in three levels, only one switching state is changed each time, the initial and middle zero vectors are respectively different state combinations, and the sequence of the action of each vector is as follows from the negative small vector: (ONN)→ (PNN)→ (PON)→ (POO)→ (PON)→ (PNN)→ (ONN). FIG. 4 is a diagram of the switching sequence of the optimal switching tube, and the action time of each basic vector is analyzed. For the firstILarge sector ofiCorrected target vector for small sector
Figure 210291DEST_PATH_IMAGE033
It is composed of
Figure 888397DEST_PATH_IMAGE034
Synthesized from three basic vectors, the basic vectors having respective times of action
Figure 181975DEST_PATH_IMAGE035
Root of Chinese characterAccording to the volt-second equilibrium principle, the method comprises the following steps:
Figure 629137DEST_PATH_IMAGE036
because the translation at the origin is made, at the moment
Figure 225334DEST_PATH_IMAGE037
Then, there is the following formula:
Figure 390736DEST_PATH_IMAGE038
from the above formula, one can obtain:
Figure 222426DEST_PATH_IMAGE039
the base vector action time can be written as a unified representation in a three-phase stationary coordinate system:
Figure 911378DEST_PATH_IMAGE040
in the above formula:
Figure 537531DEST_PATH_IMAGE041
wherein:
Figure 190229DEST_PATH_IMAGE042
respectively representing the action time of three basic vectors of the synthesized and corrected target vector, wherein the three basic vectors are respectively a zero vector and two effective vectors;
Figure 825610DEST_PATH_IMAGE043
it is indicated that the maximum value is taken,
Figure 857151DEST_PATH_IMAGE044
the representation is taken to mean the median value,
Figure 919785DEST_PATH_IMAGE045
indicating taking the minimum value.
Step three: and optimizing the midpoint potential balance compensation factor by considering the influence of the medium vector and the non-redundant small vector.
The equivalent space vector modulation realized based on the carrier wave provides that the action time of positive and negative small vectors is adjusted by adding a balance compensation factor into the injected zero sequence component to realize the neutral point potential balance, and the zero sequence component injected in the neutral point potential balance is as follows:
Figure 794200DEST_PATH_IMAGE046
wherein:
Figure 233272DEST_PATH_IMAGE047
a midpoint potential balance compensation factor representing the action time of adjusting the positive and negative redundancy small vectors;V offset representing the zero sequence component injected in the midpoint potential balance.
The neutral point potential balance is realized by adjusting the duty ratio of the positive and negative small vectors, as shown in fig. 5, the output is performed by a PI controller in a neutral point potential balance control loop, and in order to balance the neutral point potential on the direct current side, the following requirements are met:
Figure 634166DEST_PATH_IMAGE048
wherein:
Figure 867701DEST_PATH_IMAGE049
respectively representing positive and negative redundant small vectors.
The main reason for the unbalanced midpoint potential is that the midpoint current charges and discharges the direct current side capacitor, and if the midpoint current is ensured in one switching periodI 0Is 0, then midpoint potential balance can be ensured, in order toILarge sector as an example, inIThe base vector of the large sector comprisesOOO)、(PNN)、(PON)、(PNO)、(ONN) And (a)POO). Large vector (PNN) And zero vector (OOO) No influence on the center potential; middle vector (PNO) Out of the midpoint currentI c Reducing the midpoint potential; middle vector (PON) Out of the midpoint currentI b Lowering the midpoint potential, but at the same time: (PON) Is located at the firstI、IIThe boundary of the large sector, soBAfter the phase current direction is changed, the middle vector (A)PON) Current flowing into the midpointI b Increasing the midpoint potential, althoughPON) For the inflow or outflow of current to or from the centerBThe direction change of the phase current changes, but the influence on the midpoint current is alwaysI b . The influence of other medium vectors positioned at the sector switching position on the center potential can be analyzed in the same way; and for redundant positive small vectors: (POO) When the analysis is performed, the input current is satisfiedI a +I b +I c =0, so that the flowing-out midpoint current is-I a The midpoint potential is reduced, and the negative small vector(s) is/are redundantONN) Current flowing into the midpointI a The midpoint potential is improved; because of small vectors (OON) Is located at the firstIILarge sector, with current direction (+ + -) due to input currentI a +I b +I c =0, so that the midpoint current flows-I c Increasing the midpoint potential, again due to non-redundant small vectors: (ONO) Is located at the firstVILarge sector, the current direction is (+ - +), the middle point current flows-I b The midpoint potential is increased. From the above analysis, it can be seen that the effect of the vectors of the Vienna rectifier on the midpoint potential can be measured by the effect on the midpoint current.
The voltage vectors affecting the midpoint potential in the Vienna rectifier correspond to the passing midpoint current as shown in table 2:
TABLE 2 Effect of different vectors on the midpoint Current
Small vector Current at midpointI 0 Small vector Current at midpointI 0 Middle vector Current at midpointI 0
（POO） -I a （ONN） I a （PON） I b
（PPO） I c （OON） -I c （OPN） I a
（OPO） -I b （NON） I b （NPO） I c
（OPP） I a （NOO） -I a （NOP） I b
（OOP） -I c （NNO） I c （ONP） I a
（POP） I b （ONO） -I b （PNO） I c
In the analysis of the influence of the basic vector on the midpoint potential, it has been pointed out that the traditional space vector modulation realizes midpoint potential balance by adjusting the action time of the positive and negative redundant small vectors, neglects the influence of the middle vector on the midpoint potential due to uncontrollable action, and neglects the influence of the non-redundant small vectors on the midpoint potential in the two-level space voltage vector corresponding to the large sector, which causes the midpoint potential to generate low-frequency oscillation. To solve this problem, the midpoint potential balance compensation factor is optimized by considering the influence of the medium vector and the non-redundant small vectorfThe injected zero sequence component is:
Figure 229412DEST_PATH_IMAGE050
wherein:ffor compensating the optimized midpoint potential balanceAnd (4) compensating the factors.
Discussion of the invention the Vienna rectifier operates in a typical modulation ratio range, i.e.
Figure 347541DEST_PATH_IMAGE051
In the first placeIWhen a large sector is taken as an example for analysis, only the analysis needs to be carried outi、ii、vAndvithe operating status of the small sector. Although the space vector modulation is realized based on the carrier wave, the time is acted on each basic vector in the space vector modulation in the formula
Figure 478308DEST_PATH_IMAGE052
The analysis of (2) is still valid.
Analyzing the influence of the vector switching to synthesize the target vector and each basic vector in Table 2 on the center current by making one switching periodT s Middle, middle point current averageI 0=0 available:
(1) for theI-iSector:
the vector having an influence on the midpoint current includes a medium vector (PON) The action time isT 2And a pair of redundant small vectors (POO) And (a)ONN) The total action time isT 0。
Figure 882745DEST_PATH_IMAGE053
Figure 731752DEST_PATH_IMAGE054
(2) For theI-viSector:
the vector having an influence on the midpoint current includes a medium vector (PNO) The action time isT 2And a pair of redundant small vectors (POO) And (a)ONN) The total action time isT 0。
Figure 371681DEST_PATH_IMAGE055
Figure 622534DEST_PATH_IMAGE056
(3) For theI-iiSector:
the vector having an influence on the midpoint current includes a medium vector (PON) The action time isT 2Non-redundant small vectors (a)OON) The action time isT 1And a pair of redundant small vectors (POO) And (a)ONN) The total action time isT 0。
Figure 197871DEST_PATH_IMAGE057
Figure 534175DEST_PATH_IMAGE058
(4) For theI-iiSector:
the vector having an influence on the midpoint current includes a medium vector (PNO) The action time isT 2Non-redundant small vectors (a)ONO) The action time isT 1And a pair of redundant small vectors (POO) And (a)ONN) The total action time isT 0。
Figure 728527DEST_PATH_IMAGE059
Figure 833886DEST_PATH_IMAGE060
Finally obtained midpoint potential balance compensation factorf As shown in table 3:
TABLE 3 compensation factor for equilibrium of the point potentials
Figure 580125DEST_PATH_IMAGE062
In order to verify the superiority of the modulation method provided by the invention, experiments are adopted to compare the modulation effects of the traditional modulation method and the modulation method provided by the invention. As shown in FIG. 6, simulation time [0.2s, 0.5s ]]The conventional modulation method is adopted, and the simulation time is 0.5s and 0.8s]The modulation method of the present invention is adopted. (a) To obtain upper and lower tube capacitance voltageV C1AndV C2；（b) Is the midpoint offset voltage between the capacitor voltages of the upper and lower tubesV dc A comparison graph of (A); (c) Is an input current waveform diagram. It can be seen that the conventional modulation methodV C1AndV C2the ripple wave is 1.1V, the offset voltage isV dc 2V, the input current generates obvious distortion; in the modulation method of the present inventionV C1AndV C2the ripple wave is 0.4V, and the offset voltage isV dc The voltage is 0.6V, and the input current harmonic wave is obviously reduced compared with the traditional modulation method.
FIG. 7 is a modulation waveform diagram for two modulation methods, and FIG. 8 is a midpoint current waveform for two modulation methods; by adopting a traditional modulation method, the oscillation of the average current of the midpoint at the moment is obviously visible; by adopting the modulation method, the oscillation of the average current of the midpoint at the moment is obviously inhibited.
TABLE 4 simulation parameters
Figure 138146DEST_PATH_IMAGE063
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It should be understood by those skilled in the art that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by using equivalent alternatives or equivalent variations fall within the scope of the present invention.

Claims (1)

1. A Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method is characterized in that: firstly, calculating the action time of each basic vector based on the equivalent space vector modulation realized by double carriers; then, by adding a midpoint potential balance compensation factor into the zero-sequence component of the double-carrier modulation, on the basis of adjusting the action time of the positive and negative redundant small vectors to realize midpoint potential balance, a middle vector and a non-redundant small vector are inspected, the influence of the middle vector and the non-redundant small vectors on the midpoint potential is analyzed, the midpoint potential balance compensation factor is optimized, and midpoint potential low-frequency oscillation caused by the middle vector and the non-redundant small vectors is inhibited; the method specifically comprises the following steps:
step 1: determining a space voltage vector distribution diagram according to the conduction state and the current direction of a bidirectional switch tube in the Vienna rectifier topology, performing per unit on the space voltage vector, dividing the space voltage vector distribution diagram into six large sectors, and dividing each large sector into six small sectors; the method specifically comprises the following steps:
step 11: the space voltage vector distribution diagram is divided into
Figure DEST_PATH_IMAGE001
And performing per-unit treatment on each voltage vector modulo length by using Vdc/2 for six large sectors, wherein: vdc represents the voltage of the direct current side of the Vienna rectifier topology;
step 12: determining the large sector where the target vector is located, then translating the starting point of the target vector to correct the coordinate of the target vector, namely subtracting the small vector corresponding to the large sector from the target vector:
Figure 303344DEST_PATH_IMAGE002
wherein: vref is indicative of the target vector and,
Figure DEST_PATH_IMAGE003
which represents the target vector after the correction,
Figure 560013DEST_PATH_IMAGE004
the components in the three-phase stationary coordinate system are respectively
Figure DEST_PATH_IMAGE005
(ii) a V0j represents a small vector where the target vector corresponds to a large sector,
Figure 665372DEST_PATH_IMAGE006
a number indicating a large sector;
step 13: writing the three-phase relation of the corrected target vector into a unified expression:
Figure 67403DEST_PATH_IMAGE007
wherein:
Figure DEST_PATH_IMAGE009
，
Figure DEST_PATH_IMAGE011
respectively is a unified correction component of the corrected target vector under a three-phase static coordinate system;
step 14: according to
Figure 297527DEST_PATH_IMAGE012
The size relationship of the three is that each large sector is divided into
Figure DEST_PATH_IMAGE013
Six small sectors, namely:
Figure 420204DEST_PATH_IMAGE014
is the i-th small sector,
Figure DEST_PATH_IMAGE015
is the ii-th small sector,
Figure 558232DEST_PATH_IMAGE016
is the iv-th small sector area,
Figure DEST_PATH_IMAGE017
is the v-th small sector,
Figure 350738DEST_PATH_IMAGE018
is the vi small sector
Step 2: the action time of the basis vector is determined by:
Figure DEST_PATH_IMAGE019
in the above formula:
Figure 927213DEST_PATH_IMAGE020
wherein:
Figure DEST_PATH_IMAGE021
respectively representing the action time of three basic vectors of the synthesized and corrected target vector, wherein the three basic vectors are respectively a zero vector and two effective vectors;
Figure DEST_PATH_IMAGE023
it is indicated that the maximum value is taken,
Figure DEST_PATH_IMAGE025
the representation is taken to mean the median value,
Figure DEST_PATH_IMAGE027
representing taking the minimum value;
and step 3: optimizing a midpoint potential balance compensation factor by considering the influence of the medium vector and the non-redundant small vector; the method specifically comprises the following steps:
step 31: the action time of the positive and negative redundant small vectors is adjusted by injecting zero sequence components, so that the neutral potential balance is realized:
Figure 915898DEST_PATH_IMAGE028
wherein:
Figure DEST_PATH_IMAGE029
a midpoint potential balance compensation factor representing the action time of adjusting the positive and negative redundancy small vectors; voffset represents the zero sequence component injected in the midpoint potential balance;
step 32: in order to balance the midpoint potential on the dc side, the following requirements are satisfied:
Figure 917221DEST_PATH_IMAGE030
wherein:
Figure DEST_PATH_IMAGE031
respectively representing positive and negative redundant small vectors;
step 33: in order to eliminate the midpoint potential low-frequency oscillation caused by the influence of the medium vector and the non-redundant small vector, the midpoint potential balance compensation factor is optimized, the average value of the midpoint current in each switching period is ensured to be 0, and the optimized zero-sequence component is as follows:
Figure 536421DEST_PATH_IMAGE032
wherein: f is an optimized midpoint potential balance compensation factor, and the expression of f in each sector is as follows:
(1) for large sector I: in the small sector i, the sector i,
Figure DEST_PATH_IMAGE033
(ii) a In the small sector ii, the sector ii is,
Figure 944399DEST_PATH_IMAGE034
(ii) a In the small sector v of the cell,
Figure DEST_PATH_IMAGE035
(ii) a In the small sector vi,
Figure 408879DEST_PATH_IMAGE036
；
(2) for large sector II: in the small sector i, the sector i,
Figure DEST_PATH_IMAGE037
(ii) a In the small sector ii, the sector ii is,
Figure 530287DEST_PATH_IMAGE038
(ii) a In the small sector iii, the sector iii,
Figure DEST_PATH_IMAGE039
(ii) a In the small sector vi,
Figure 930176DEST_PATH_IMAGE040
；
(3) for large sector III: in the small sector i, the sector i,
Figure DEST_PATH_IMAGE041
(ii) a In the small sector ii, the sector ii is,
Figure 950085DEST_PATH_IMAGE042
(ii) a In the small sector iii, the sector iii,
Figure DEST_PATH_IMAGE043
(ii) a In the small sector vi,
Figure 408135DEST_PATH_IMAGE044
；
(4) for large sector IV: in the small sector ii, the sector ii is,
Figure DEST_PATH_IMAGE045
(ii) a In the small sector iii, the sector iii,
Figure 72466DEST_PATH_IMAGE046
(ii) a In the small sector iv, the sector number,
Figure DEST_PATH_IMAGE047
(ii) a In the small sector v of the cell,
Figure 767889DEST_PATH_IMAGE048
；
(5) for large sector V: in the small sector iii, the sector iii,
Figure DEST_PATH_IMAGE049
(ii) a In the small sector iv, the sector number,
Figure 462045DEST_PATH_IMAGE050
(ii) a In the small sector v of the cell,
Figure DEST_PATH_IMAGE051
(ii) a In the small sector vi,
Figure DEST_PATH_IMAGE052
；
(6) for large sector VI: in the small sector i, the sector i,
Figure DEST_PATH_IMAGE053
(ii) a In the small sector iv, the sector number,
Figure DEST_PATH_IMAGE054
(ii) a In the small sector v of the cell,
Figure DEST_PATH_IMAGE055
(ii) a In the small sector vi,
Figure DEST_PATH_IMAGE056
。
CN202210052046.2A 2022-01-18 2022-01-18 Vienna rectifier midpoint potential low-frequency oscillation suppression modulation method Pending CN114094856A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114583982A (en) * 2022-05-06 2022-06-03 南京理工大学 Vienna rectifier comprehensive optimization modulation method under unbalanced working condition
CN114884325A (en) * 2022-06-14 2022-08-09 哈尔滨工业大学 Electrolytic capacitor-free Vienna rectifier midpoint voltage fluctuation suppression hybrid modulation method
CN116827148A (en) * 2023-06-07 2023-09-29 广州工程技术职业学院 Optimized modulation method, device, terminal and medium for Vienna rectifier

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CN106357135A (en) * 2016-09-19 2017-01-25 山东大学 VIENNA rectifier neutral point potential alternating-direct-current component balance control method
CN111987920A (en) * 2020-07-23 2020-11-24 南京理工大学 Three-level space vector modulation method

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CN106357135A (en) * 2016-09-19 2017-01-25 山东大学 VIENNA rectifier neutral point potential alternating-direct-current component balance control method
CN111987920A (en) * 2020-07-23 2020-11-24 南京理工大学 Three-level space vector modulation method

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114583982A (en) * 2022-05-06 2022-06-03 南京理工大学 Vienna rectifier comprehensive optimization modulation method under unbalanced working condition
CN114583982B (en) * 2022-05-06 2022-07-19 南京理工大学 Vienna rectifier comprehensive optimization modulation method under unbalanced working condition
CN114884325A (en) * 2022-06-14 2022-08-09 哈尔滨工业大学 Electrolytic capacitor-free Vienna rectifier midpoint voltage fluctuation suppression hybrid modulation method
CN114884325B (en) * 2022-06-14 2022-10-14 哈尔滨工业大学 Electrolytic capacitor-free Vienna rectifier midpoint voltage fluctuation suppression hybrid modulation method
CN116827148A (en) * 2023-06-07 2023-09-29 广州工程技术职业学院 Optimized modulation method, device, terminal and medium for Vienna rectifier
CN116827148B (en) * 2023-06-07 2023-12-05 广州工程技术职业学院 Optimized modulation method, device, terminal and medium for Vienna rectifier

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