CN106533206B - The neutral-point voltage balance method of the double pwm converters of back-to-back three level - Google Patents
The neutral-point voltage balance method of the double pwm converters of back-to-back three level Download PDFInfo
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Abstract
The invention discloses a kind of neutral-point voltage balance methods of the double pwm converters of back-to-back three level, the first sector will be normalized to by mathematical coordinates rotation transformation positioned at the space vector of voltage of other sectors to unifiedly calculate, therefore difference calculation processing need not be carried out for each sector, to simplify the complexity of algorithm.Simultaneously, the present invention makes full use of the mid-point voltage control ability of grid side converter or machine-side converter, when wherein side control ability can not be provided completely by other side converter, avoid the shortcomings that mid-point voltage control action that both sides converter independent control mid-point voltage may be brought in conventional method mutually weakens, to reduce the mid-point voltage fluctuation of double pwm converters back-to-back, the active balance control of alignment voltage is realized.
Description
Technical field
The present invention is related with three-level converter, particularly belongs to a kind of midpoint electricity of the double pwm converters of back-to-back three level
Press balance control method.
Background technology
With the development of power electronic technique, three-level converter is with its higher delivery efficiency and lower output electricity
The advantages that flowing percent harmonic distortion, obtains in fields such as big-power transducer, three-phase grid-connected inverter and three-phase uninterrupted power supplys
It is widely applied.
Currently, leaning against based on heavy-duty motor drive area and wind power generation field occur by three-level topology
The double pwm converters of three level are carried on the back, which includes the machine-side converter of the grid side converter and connection motor that connect power grid,
And grid side converter and machine-side converter all have the ability of balance mid-point voltage.
Currently, mostly using independent side converter in disclosed technical literature to control mid-point voltage, such as only with net
Side converter controls mid-point voltage, although this method can realize the balance control of mid-point voltage, since net side becomes
The modulation degree of parallel operation is higher, therefore it balances the ability of mid-point voltage than relatively limited.
In addition, an also technology path is to comprehensively utilize the control ability of both sides converter alignment voltage,
Although independent mid-point voltage control strategy, which is respectively adopted, in grid side converter and machine-side converter can enhance alignment voltage
Control ability, but due to not distinguishing the voltage-controlled size of both sides converter alignment and side in each switch periods specifically
To, therefore this method is likely to occur overcompensation there is the control action of both sides converter alignment voltage and that cancels out each other asks
Topic.
Referring to《The double pwm converter capacitor voltage balance Comprehensive Controls of three level》, Fan Bishuan, Tan Guanzheng, Fan Shaosheng, motor
With control journal, 2014,18 (1)：38-43, the paper propose a kind of capacitance midpoint electricity of grid side converter and machine-side converter
Weighing apparatus integrated control strategy is flattened, the influence of all redundancy small vector alignment voltages of three-level converter is analyzed, gives electricity
Pressure vector is located at midpoint average current calculating formula when each sector, by each phase current of subsequent time and capacitance voltage reference
The prediction of amount, it is the minimum merit functions of mid-point voltage fluctuation to obtain a target, by adjusting the distribution of redundant vectors time because
Son reaches the target of control mid-point voltage fluctuation.Although this method will not cause both sides converter alignment voltage overcompensation and
Undercompensation, but it distributes identical redundant vectors time factor to both sides converter, still limits two to a certain extent
The control ability of side converter alignment voltage, and this method needs constantly interative computation, algorithm to realize more complicated.Cause
This, in view of the deficiencies of the prior art, this field urgently proposes to realize simply in a kind of algorithm, can effectively realize back-to-back
The neutral-point voltage balance method of the double pwm converters of three level.
Invention content
The technical problem to be solved in the present invention is to provide a kind of neutral point voltage balances of the double pwm converters of back-to-back three level
The shortcomings that control method, the control action that can be not only generated to avoid both sides converter independent control mid-point voltage mutually weakens,
And it can overcome the problems, such as that both sides converter is unable to fully control mid-point voltage.
To solve the above-mentioned problems, the neutral point voltage balance control of the double pwm converters of back-to-back three level provided by the invention
Method processed, includes the following steps：
Step 1, the voltage vector of the voltage vector of grid side converter and machine-side converter is become respectively using coordinate transform
Two-phase stationary coordinate system is changed to, and is changed into rower according to two voltage vectors of DC voltage value pair；
Step 2, according to grid side converter voltage vector and machine-side converter voltage vector in two-phase stationary coordinate system
Value judges the actual sector number where two voltage vectors；
Step 3, the grid side converter voltage vector and machine-side converter voltage changed mark using transformation matrix of coordinates are sweared
Quantitative change shifts to the first sector；
Step 4, according to after rotation transformation grid side converter voltage vector and machine-side converter voltage vector judge rotation
Small sector triangle number in first sector where two voltage vectors after transformation；
Step 5, according to grid side converter voltage vector and the Bu Tong small sector triangle where machine-side converter voltage vector
Shape determines three fundamental voltage space vectors and the corresponding midpoint electric current of grid side converter and machine-side converter respectively；
Step 6, according to grid side converter voltage vector and the Bu Tong small sector triangle where machine-side converter voltage vector
Shape calculates the action time of the three fundamental voltage space vectors acted on successively；
Step 7, it is respectively inputted according to the deviant of DC side mid-point voltage and grid side converter and machine-side converter
Three-phase electricity flow valuve calculates separately the neutral point voltage balance factor of grid side converter and machine-side converter side；
Step 8, according to grid side converter and machine-side converter respectively the action time of three fundamental voltage space vectors and
The neutral point voltage balance factor being calculated calculates separately and obtains the output pulse duration that vector is located at different small sector triangles
Than；
Step 9, according to the actual sector number of grid side converter voltage vector and machine-side converter voltage vector, respectively by net
The duty cycle information that side converter and machine-side converter are calculated in the first sector map back grid side converter voltage vector and
Machine-side converter voltage vector respectively where actual sector, and duty cycle information is scaled corresponding fiducial value to generate
Pwm pulse respectively drives grid side converter and machine-side converter.
The invention has the beneficial effects that：
1) present invention will be normalized to the first fan by mathematical coordinates rotation transformation positioned at the space vector of voltage of other sectors
Area unifiedly calculates, therefore need not carry out difference calculation processing for each sector, to simplify the complexity of algorithm；
2) present invention makes full use of the mid-point voltage control ability of grid side converter or machine-side converter, when wherein side
Control ability can not be provided completely by other side converter, avoid converter independent control mid-point voltage in both sides in conventional method
The shortcomings that mid-point voltage control action that may be brought mutually weakens, to reduce the midpoint electricity of double pwm converters back-to-back
Pressure fluctuation realizes the active balance control of alignment voltage.
Description of the drawings
Fig. 1 is the circuit diagram of the double pwm converters of applicable back-to-back three level of the method for the present invention；
Fig. 2 is the region division schematic diagram of space vector of voltage in the method for the present invention；
Fig. 3 is the division schematic diagram between the first sector voltage vector relationship and delta in the method for the present invention；
Fig. 4 a to Fig. 4 f are the fundamental voltage space vector effects in each delta in the first sector in the method for the present invention
Schematic diagram.
Fig. 5 is the algorithm flow schematic diagram in the method for the present invention.
Specific implementation mode
The present invention is described in further detail with specific implementation mode below in conjunction with the accompanying drawings.
The present invention is suitable for the double pwm converters of back-to-back three level, the converter include grid side converter (hereinafter referred to as
GVSC) and machine-side converter (hereinafter referred to as MVSC), as shown in Figure 1, neutral-point voltage balance method includes the following steps：
S1：Using Clarke coordinate transform respectively by the three-phase voltage vector of the three-phase voltage vector sum MVSC of GVSC
Change into rower to two-phase stationary coordinate system, and according to two voltage vectors of DC voltage value pair, is divided into：
S11：GVSC voltage vectors are transformed into two-phase stationary coordinate system, and according to DC voltage value to two-phase voltage vector
Change into rower, is as follows：
(1) voltage vector is transformed under two-phase stationary coordinate system using following formula；
In formula, uag、ubgAnd ucgRespectively component of the GVSC voltage vectors in abc coordinate systems；uαg、uβgRespectively GVSC
Component of the voltage vector in α β coordinate systems；
(2) amplitude limiting processing is carried out to two-phase voltage vector according to DC voltage value；
IfThen
IfThen
In formula, udcFor DC voltage value；uαgL、uβgLRespectively GVSC voltage vectors after amplitude limiting processing in α β coordinate systems
In component；
(3) two-phase voltage vector is changed into rower according to DC voltage value；
In formula, vαg、vβgThe respectively per unit value of component of the GVSC voltage vectors in α β coordinate systems.
S12：MVSC voltage vectors are transformed into two-phase stationary coordinate system, and according to DC voltage value to two-phase voltage vector
Change into rower, is as follows：
(1) voltage vector is transformed under two-phase stationary coordinate system using following formula；
In formula, uam、ubmAnd ucmRespectively component of the MVSC voltage vectors in abc coordinate systems；uαm、uβmRespectively MVSC
Component of the voltage vector in α β coordinate systems；
(2) amplitude limiting processing is carried out to two-phase voltage vector according to DC voltage value；
IfThen
IfThen
In formula, udcFor DC voltage value；uαmL、uβmLRespectively MVSC voltage vectors after amplitude limiting processing in α β coordinate systems
In component；
(3) two-phase voltage vector is changed into rower according to DC voltage value；
In formula, vαm、vβmThe respectively per unit value of component of the MVSC voltage vectors in α β coordinate systems.
It should be noted that the related physical quantity of grid side converter GVSC contains subfix in symbol in subsequent step
The related physical quantity of g, machine-side converter MVSC contain subfix m in symbol, illustrate hereby.
S2：Judge that voltage is sweared according to the component value of GVSC voltage vectors and MVSC voltage vectors in two-phase stationary coordinate system
It numbers (according to clockwise the actual sector measured in the regular hexagon shown in Fig. 2 formed by three level fundamental voltage space vectors
Regular hexagon is divided into 6 sector triangles by direction, and number is respectively from 1 to 6), it is divided into：
S21：The reality where voltage vector is judged according to component value of the GVSC voltage vectors in two-phase stationary coordinate system
Sector number, the specific method is as follows：
(1) in order to judge the sector number where GVSC voltage vectors, three variables a, b, c of definition first are simultaneously using public as follows
Formula calculates the value of a, b and c；
(2) defined variable P, value calculate according to the following formula：
P=sign (a)+2sign (b)+4sign (c)
In formula, sign () is to seek data symbol function, is defined as follows shown：
(3) the actual sector N where voltage vector is judged according to the value of following table and P；
S22：Judge that the sector number where voltage vector, specific method are identical as S21 according to MVSC voltage vector values.
S3：The GVSC voltage vectors and MVSC voltage vectors that mark is changed are converted into the first fan using transformation matrix of coordinates
Area is divided into：
S31：The GVSC voltage vectors that mark is changed are converted into the first sector using transformation matrix of coordinates, specific method is such as
Under：
The voltage vector of the first sector to the 6th sector is uniformly transformed into the first sector using following coordinate transform formula：
In formula, vαTg、vβTgRespectively GVSC voltage vectors after coordinate transform in the component of the first sector；TN1For N
The transformation matrix of coordinates of sector to the first sector, N values are from 1 to 6；Wherein：
1) when voltage vector is located at the first sector (delta-shaped region surrounded by vector 000, PNN and PPN in Fig. 2),
Corresponding transformation matrix of coordinates is
2) when voltage vector is located at the second sector (delta-shaped region surrounded by vector 000, PPN and NPN in Fig. 2),
Corresponding transformation matrix of coordinates is
3) when voltage vector is located at third sector (delta-shaped region surrounded by vector 000, NPN and NPP in Fig. 2),
Corresponding transformation matrix of coordinates is
4) when voltage vector is located at the 4th sector (delta-shaped region surrounded by vector 000, NPP and NNP in Fig. 2),
Corresponding transformation matrix of coordinates is
5) when voltage vector is located at the 5th sector (delta-shaped region surrounded by vector 000, NNP and PNP in Fig. 2),
Corresponding transformation matrix of coordinates is
6) when voltage vector is located at the 6th sector (delta-shaped region surrounded by vector 000, PNP and PNN in Fig. 2),
Corresponding transformation matrix of coordinates is
S32：MVSC voltage vectors that mark is changed are converted into the first sector using transformation matrix of coordinates, specific method with
S31 is identical.
S4：First sector triangle is by U0~U6Be divided into 6 small sector gable, number be followed successively by A, B, C, D, E and
F, wherein U0Refer to zero vector 000, NNN and PPP (these three vectors overlap, i.e. the dot of α β coordinate systems), U1Refer to small arrow
Measure 0NN and P00 (coincidence of the two vectors), U2Refer to small vector PP0 and 00N (coincidence of the two vectors), U3It refers to swearing greatly
Measure PNN, U4Refer to middle vector P0N, U5Refer to big vector PPN, U6For middle vector U4Half, the zero vector, small arrow
Amount, the professional technique noun that the big vector of middle vector sum is three-level converter space vector modulation；
As shown in figure 3, by U between A deltas0、U1And U6It surrounds, by U between B deltas0、U6And U2It is surrounded, C triangles
Shape section is by U1、U4And U6It is surrounded, by U between D deltas2、U4And U6It is surrounded, by U between E deltas1、U3And U4It is enclosed
At by U between F deltas2、U4And U5It is surrounded；
According to after rotation transformation GVSC voltage vectors and MVSC voltage vectors judge that the voltage vector after rotation transformation exists
It numbers, is divided between small sector delta where first sector：
S41：Judge the number between the delta where the GVSC voltage vectors after rotation transformation, is specifically divided into following feelings
Condition：
1) Rule of judgment of the GVSC voltage vectors between A deltas after rotation transformation is：
2) Rule of judgment of the GVSC voltage vectors between B deltas after rotation transformation is：
3) Rule of judgment of the GVSC voltage vectors between C deltas after rotation transformation is：
4) Rule of judgment of the GVSC voltage vectors between D deltas after rotation transformation is：
5) Rule of judgment of the GVSC voltage vectors between E deltas after rotation transformation is：
6) Rule of judgment of the GVSC voltage vectors between F deltas after rotation transformation is：
S42：Judge the number between the delta where the MVSC voltage vectors after rotation transformation, specific method and S41
It is identical.
S5：Between different deltas where GVSC voltage vectors and MVSC voltage vectors respectively determine GVSC and
Tri- fundamental voltage space vectors of MVSC and midpoint electric current, are divided into：
S51：It determines tri- fundamental voltage space vectors of GVSC and midpoint electric current, is as follows：
(1) it is respectively v to set the three fundamental voltage space vectors acted on successively1g, v2gAnd v3g, then six of the first sector
Selection is carried out according to the following table in corresponding three fundamental voltage space vectors between small delta.
(2) it is respectively i to set the corresponding midpoint electric current of three fundamental voltage space vectors acted on successively1g, i2gAnd i3g, then
The corresponding midpoint electric current of three fundamental voltage space vectors between the first small delta in sector six is selected according to following table.
When (3) the 2nd~6 sectors transform to 1 sector, since three fundamental voltage space vectors of corresponding position become
Change, thus corresponding midpoint electric current also differs, therefore it is according to the actual sector where GVSC voltage vectors that fundamental voltage is empty
Between the corresponding midpoint electric current of vector also accordingly converted, specific change situation is as shown in the table.
In table, iaNg, ibNgAnd icNgFor positioned at the corresponding three-phase current of GVSC voltage vectors of n-th sector.
S52：Determine that tri- fundamental voltage space vectors of GVSC and midpoint electric current, specific method are identical as S51.
S6：Three acted on successively according to the different triangle interval computations where GVSC voltage vectors and MVSC voltage vectors
The action time of a fundamental voltage space vector, it is divided into：
S61：The three fundamental voltage skies acted on successively according to the different triangle interval computations where GVSC voltage vectors
Between vector action time, be specifically divided into：
1) between A deltas, the effect schematic diagram of three fundamental voltage space vectors as shown in fig. 4 a, divide by action time
It is not：
Wherein, t1gFor the action time of vector 0NN；t2gFor the action time of vector 00N；t3gFor vector 000 effect when
Between, TsFor switch periods；
2) between B deltas, the effect schematic diagram of three fundamental voltage space vectors is as shown in Figure 4 b, action time point
It is not：
Wherein, t1gFor the action time of vector 00N；t2gFor the action time of vector 000；t3gFor vector P00 effect when
Between, TsFor switch periods；
3) between C deltas, the effect schematic diagram of three fundamental voltage space vectors as illustrated in fig. 4 c, divide by action time
It is not：
Wherein, t1gFor the action time of vector 0NN；t2gFor the action time of vector 00N；t3gFor vector P0N effect when
Between, TsFor switch periods；
4) between D deltas, the effect schematic diagram of three fundamental voltage space vectors as shown in figure 4d, divide by action time
It is not：
Wherein, t1gFor the action time of vector 00N；t2gFor the action time of vector P0N；t3gFor vector P00 effect when
Between, TsFor switch periods；
5) between E deltas, the effect schematic diagram of three fundamental voltage space vectors as shown in fig 4e, divide by action time
It is not：
Wherein, t1gFor the action time of vector 0NN；t2gFor the action time of vector PNN；t3gFor vector P0N effect when
Between, TsFor switch periods；
6) between F deltas, the effect schematic diagram of three fundamental voltage space vectors as shown in fig. 4f, divide by action time
It is not：
Wherein, t1gFor the action time of vector 00N；t2gFor the action time of vector P0N；t3gFor vector PPN effect when
Between, TsFor switch periods；
S62：The three fundamental voltage skies acted on successively according to the different triangle interval computations where MVSC voltage vectors
Between vector action time, specific method is identical as S61.
It should be noted that the PWM carrier waves of GVSC and MVSC be taken as it is same.
S7：GVSC is calculated separately according to the deviant of DC side mid-point voltage and GVSC and MVSC input three-phase electricity flow valuve
With the respective neutral point voltage balance factor in the sides MVSC, it is as follows：
(1) assume that the mid-point voltage for needing to adjust is uadj, then regulating time distribution factor k calculated according to the following formula：
In formula, uadj=-uN0=udc1-udc2, CdcFor the size of dc-link capacitance, uN0For mid-point voltage value, udc1With
udc2Respectively direct current bus bar holds voltage value and lower capacitance voltage value；
(2) two neutral point voltage balance factor k are setgAnd kmTo redistribute grid side converter and machine-side converter first
The action time of fundamental voltage space vector；
Current midpoint voltage is uN0, then the maximum balance factor calculation formula of the neutral-point voltage balance of grid side converter
For：
The maximum balance factor calculation formula of the neutral-point voltage balance of machine-side converter is：
(3) constraint of the neutral point voltage balance factor calculates
Take kg=k1, km=k2, k is corrected according to following rulegAnd kmValue, it is specific as follows shown in：
If 1) abs (k1)≤1, abs (k2)≤1, then enable km=0, kgIt remains unchanged；
If 2) abs (k1)≤1, abs (k2)>1, then enable km=0, kgIt remains unchanged；
If 3) abs (k1)>1, abs (k2)≤1, then enable kg=0, kmIt remains unchanged；
If 4) abs (k1)>1, abs (k2)>1, then enable kg=sign (kg), kmIt is calculated by following formula：
Wherein uadjGFor the mid-point voltage value that net side current transformer can be adjusted, calculation formula is as follows：
S8：According to GVSC and the MVSC respectively action time of three fundamental space vectors and the balance factor being calculated
Value calculates output pulse duty factor, is divided into：
S81：According to the action time of tri- fundamental space vectors of GVSC and the balance factor value being calculated, output is calculated
Pulse duty factor specifically includes：
1) three variable t are definedag, tbgAnd tcg, value is respectively：
Define three variable da, dbAnd dcAs three dutyfactor values, it is respectively according to the following formula
2) according between the different deltas where GVSC voltage vectors, the effective duty cycle d of three-phase bridge arm is selectedAg、dBg
And dCg, concrete condition is as shown in the table.
S82：According to the action time of tri- fundamental space vectors of MVSC and the balance factor value being calculated, output is calculated
Pulse duty factor, specific method are identical as S81.
S9：It is accounted for what is be calculated in the first sector according to the actual sector number of GVSC voltage vectors and MVSC voltage vectors
Sky goes back to the original sector at respectively place than information MAP, and duty ratio is scaled corresponding fiducial value, to generate pwm pulse point
Not Qu Dong GVSC and MVSC, be divided into：
S91：It is tabled look-up the duty cycle information that will be calculated in the first sector according to the actual sector number of GVSC voltage vectors
The original sector where GVSC is mapped back, and duty ratio is scaled corresponding fiducial value, is respectively driven with generating pwm pulse
GVSC is specifically included：
(1) according to the actual sector where GVSC voltage vectors, two groups of duty cycle informations of three-phase bridge arm are determined；
If the GVSC voltage vectors after rotation transformation are located at the section A, C and E of the first sector, bridge arm duty ratio value
As shown in the table；
If the GVSC voltage vectors after rotation transformation are located at the section B, D and F of the first sector, bridge arm duty ratio value
As shown in the table；
(2) determine that tri- bridge arms of GVSC correspond to the value of six modulating waves using following formula, it is specific as follows shown：
In formula, CPA1g、CPA2gThe respectively value of two modulating waves of A phases；CPB1g、CPB2gRespectively B phases two modulating waves
Value；CPC1g、CPC2gThe respectively value of two modulating waves of C phases；CNT is the peak value of triangular carrier.
S92：It is tabled look-up the duty cycle information that will be calculated in the first sector according to the actual sector number of MVSC voltage vectors
The original sector where MVSC is mapped back, and duty ratio is scaled corresponding fiducial value, is respectively driven with generating pwm pulse
MVSC, specific method are identical as S91.
The flow diagram of the method for the invention is as shown in Figure 5.
This method avoid grid side converters in conventional method and machine-side converter independent control mid-point voltage to bring
Mid-point voltage control the shortcomings that mutually weakening, can make full use of the mid-point voltage control of grid side converter and machine-side converter
Ability realizes the balance control of mid-point voltage to reduce the fluctuation of mid-point voltage.
The present invention has been described in detail through specific embodiments, above-described embodiment be only the present invention compared with
Good embodiment, the invention is not limited in the above embodiments.Without departing from the principles of the present invention, the technology of this field
The equivalent replacement and improvement that personnel make are regarded as in the technology scope that the present invention is protected.
Claims (10)
1. a kind of neutral-point voltage balance method of the double pwm converters of back-to-back three level, which is characterized in that including following step
Suddenly：
Step 1, the voltage vector of the voltage vector of grid side converter and machine-side converter is transformed to respectively using coordinate transform
Two-phase stationary coordinate system, and changed into rower according to two voltage vectors of DC voltage value pair；
Step 2, sentenced according to the value of grid side converter voltage vector and machine-side converter voltage vector in two-phase stationary coordinate system
Actual sector number where disconnected two voltage vectors；
Step 3, the grid side converter voltage vector and machine-side converter voltage vector changed mark using transformation matrix of coordinates are become
Shift to the first sector；
Step 4, according to after rotation transformation grid side converter voltage vector and machine-side converter voltage vector judge rotation transformation
Small sector triangle number in first sector where two voltage vectors afterwards；
Step 5, according to grid side converter voltage vector and the Bu Tong small sector triangle where machine-side converter voltage vector, divide
Not Que Ding grid side converter and machine-side converter three fundamental voltage space vectors and corresponding midpoint electric current；
Step 6, according to grid side converter voltage vector and the Bu Tong small sector triangle where machine-side converter voltage vector, meter
Calculate the action time of the three fundamental voltage space vectors acted on successively；
Step 7, the three-phase respectively inputted according to the deviant of DC side mid-point voltage and grid side converter and machine-side converter
Current value calculates separately the neutral point voltage balance factor of grid side converter and machine-side converter side；
Step 8, according to the respectively action time of three fundamental voltage space vectors and the calculating of grid side converter and machine-side converter
The obtained neutral point voltage balance factor calculates separately and obtains the output pulse duty factor that vector is located at different small sector triangles；
Step 9, according to the actual sector number of grid side converter voltage vector and machine-side converter voltage vector, net side is become respectively
The duty cycle information that parallel operation and machine-side converter are calculated in the first sector maps back grid side converter voltage vector and pusher side
Converter voltage vector respectively where actual sector, and duty cycle information is scaled corresponding fiducial value to generate PWM arteries and veins
Punching respectively drives grid side converter and machine-side converter.
2. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 1, feature
It is, in step 1, using Clarke transform by three-phase voltage vector to two-phase stationary coordinate system, and according to direct current
Voltage value changes voltage vector into rower, the specific steps are：
1) voltage vector is transformed under two-phase stationary coordinate system using formula (1)；
In above formula, ua、ubAnd ucRespectively component of the voltage vector in abc coordinate systems, uα、uβRespectively voltage vector is sat in α β
Component in mark system；
2) amplitude limiting processing is carried out to two-phase voltage vector, wherein
IfThen
IfThen
In above formula, udcFor DC voltage value, uαL、uβLRespectively point of the voltage vector after amplitude limiting processing in α β coordinate systems
Amount；
3) formula (2) is utilized to change two-phase voltage vector into rower；
In above formula, vα、vβThe respectively per unit value of component of the voltage vector in α β coordinate systems.
3. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 2, feature
It is, the method for sector number is as follows where the voltage vector of grid side converter or machine-side converter is judged in step 2：
1) defined variable a, b, c, with component u of the voltage vector in α β coordinate systemsα、uβBetween relationship be
2) relationship between defined variable P, with variable a, b, c is
P=sign (a)+2sign (b)+4sign (c)
In above formula, sign () is to seek data symbol function, is defined as
3) judge that the relationship of sector number N, wherein P and N where voltage vector are according to the value of variable P
Wherein, the value range of N is 1~6.
4. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 3, feature
It is, in step 3, voltage vector is converted into the first sector using coordinate transform formula (3)；
In above formula, vαT、vβTRespectively voltage vector after coordinate transform in the component of the first sector, TN1For the sectors N to
The value of the transformation matrix of coordinates of one sector, N is 1~6, wherein：
When voltage vector is located at the first sector, corresponding transformation matrix of coordinates is
When voltage vector is located at the second sector, corresponding transformation matrix of coordinates is
When voltage vector is located at third sector, corresponding transformation matrix of coordinates is
When voltage vector is located at four sectors, corresponding transformation matrix of coordinates is
When voltage vector is located at five sectors, corresponding transformation matrix of coordinates is
When voltage vector is located at six sectors, corresponding transformation matrix of coordinates is
5. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 4, feature
It is, first sector is divided into the six small sector triangles of A~F, by U between A deltas0、U1And U6It surrounds, B triangles
Section is by U0、U6And U2It is surrounded, by U between C deltas1、U4And U6It is surrounded, by U between D deltas2、U4And U6It is surrounded,
By U between E deltas1、U3And U4It is surrounded, by U between F deltas2、U4And U5It is surrounded, wherein U0For zero vector 000, NNN
And PPP, U1For small vector 0NN and P00, U2For small vector PP0 and 00N, U3For big vector PNN, U4For middle vector P0N, U5It is big
Vector PPN, U6For middle vector U4Half；In step 4：
Rule of judgment of the voltage vector between A deltas after rotation transformation be
Rule of judgment of the voltage vector between B deltas after rotation transformation be
Rule of judgment of the voltage vector between C deltas after rotation transformation be
Rule of judgment of the voltage vector between D deltas after rotation transformation be
Rule of judgment of the voltage vector between E deltas after rotation transformation be
Rule of judgment of the voltage vector between F deltas after rotation transformation be
6. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 5, feature
It is, in steps of 5 the determination side of three fundamental voltage space vectors and midpoint electric current of grid side converter or machine-side converter
Method is as follows：
1) it is respectively v to set the three fundamental voltage space vectors acted on successively1, v2And v3, then the small delta in the first sector six
Between corresponding three fundamental voltage space vectors determined according to following table；
2) it is respectively i to set the corresponding midpoint electric current of three fundamental voltage space vectors acted on successively1, i2And i3, then the first sector
The corresponding midpoint electric current of three fundamental voltage space vectors is determined according to following table between six small deltas；
3) the corresponding midpoint electric current of fundamental voltage space vector is carried out according to the following table according to the actual sector where voltage vector
Corresponding transformation；
In upper table, iaN, ibNAnd icNFor the corresponding three-phase current in the sectors N.
7. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 6, feature
It is, the action time meter for three fundamental voltage space vectors that grid side converter or machine-side converter act on successively in step 6
Calculation method is as follows：
Voltage vector after rotation transformation is between A deltas, the action time difference of three fundamental voltage space vectors
ForWherein, t1For the action time of vector 0NN；t2For the action time of vector 00N；t3For arrow
The action time of amount 000, TsFor switch periods；
Voltage vector after rotation transformation is between B deltas, the action time difference of three fundamental voltage space vectors
ForWherein, t1For the action time of vector 00N；t2For the action time of vector 000；t3For arrow
Measure the action time of P00；
Voltage vector after rotation transformation is between C deltas, the action time difference of three fundamental voltage space vectors
ForWherein, t1For the action time of vector 0NN；t2For the action time of vector 00N；t3For
The action time of vector P0N；
Voltage vector after rotation transformation is between D deltas, the action time difference of three fundamental voltage space vectors
ForWherein, t1For the action time of vector 00N；t2For the action time of vector P0N；t3For
The action time of vector P00；
Voltage vector after rotation transformation is between E deltas, the action time difference of three fundamental voltage space vectors
ForWherein, t1For the action time of vector 0NN；t2For the action time of vector PNN；t3For arrow
Measure the action time of P0N；
Voltage vector after rotation transformation is between F deltas, the action time difference of three fundamental voltage space vectors
ForWherein, t1For the action time of vector 00N；t2For the action time of vector P0N；t3For arrow
Measure the action time of PPN.
8. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 7, feature
It is, in step 7, the neutral point voltage balance factor computational methods of grid side converter or machine-side converter are as follows：
1) it sets and needs the mid-point voltage adjusted as uadj, regulating time distribution factor k, wherein C are calculated according to formula (4)dcFor direct current
The size of bus capacitor；
Wherein, uadj=-uN0=udc1-udc2, uN0For mid-point voltage value, udc1And udc2The respectively upper capacitance voltage of DC bus
Value and lower capacitance voltage value；
2) the maximum balance factor k of the neutral-point voltage balance of grid side converter is calculated according to formula (5)1, according to formula (6)
The maximum balance factor k of the neutral-point voltage balance of computer-side converter2；
Wherein, i1g、i2g、i3gThe corresponding midpoint electricity of three fundamental voltage space vectors that respectively grid side converter acts on successively
Stream, t1g、t2g、t3gThe action time for three fundamental voltage space vectors that respectively grid side converter acts on successively, i1m、i2m、
i3mThe corresponding midpoint electric current of three fundamental voltage space vectors that respectively machine-side converter acts on successively, t1m、t2m、t3mRespectively
For the action time for three fundamental voltage space vectors that machine-side converter acts on successively；
3) two neutral point voltage balance factor k are setgAnd kmRedistribute the first fundamental voltage of grid side converter and machine-side converter
The action time of space vector, take kg=k1And km=k2, neutral point voltage balance factor kgAnd kmModification method it is as follows：
(1) if abs (k1)≤1, abs (k2)≤1, then enable km=0, kgIt remains unchanged；
(2) if abs (k1)≤1, abs (k2)>1, then enable km=0, kgIt remains unchanged；
(3) if abs (k1)>1, abs (k2)≤1, then enable kg=0, kmIt remains unchanged；
(4) if abs (k1)>1, abs (k2)>1, then enable kg=sign (kg), kmIt is calculated according to formula (7)；
Wherein uadjGFor the mid-point voltage value that net side current transformer can be adjusted, calculation formula is
9. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 8, feature
It is, in step 8, the computational methods for exporting pulse duty factor are：
1) three variable t are defineda, tbAnd tc, and calculated according to formula (8)；
Define three variable da、dbAnd dcAs three dutyfactor values, calculated according to formula (9)；
In above formula, kiRepresent the neutral point voltage balance factor k of grid side convertergOr the neutral point voltage balance factor of machine-side converter
km；
2) according between the different deltas where the voltage vector after rotation transformation, the effective of three-phase bridge arm is selected according to following table
Duty ratio；
Wherein, dA、dBAnd dCFor the effective duty cycle of three-phase bridge arm.
10. the neutral-point voltage balance method of the double pwm converters of back-to-back three level according to claim 9, special
Sign is that the specific method of step 9 includes：
1) according to the actual sector where grid side converter voltage vector or machine-side converter voltage vector, two groups of three-phase bridge arm
Duty cycle information conversion is as follows：
When the voltage vector after rotation transformation is between A deltas or between C deltas or between E deltas, map back
Two duty ratios of the three-phase bridge arm of former sector are according to following table value where voltage vector；
When the voltage vector after rotation transformation is between B deltas or between D deltas or between F deltas, map back
Two duty ratios of the three-phase bridge arm of former sector are according to following table value where voltage vector；
2) value of corresponding six modulating waves of three bridge arms is determined according to formula (10)
In above formula, CPA1、CPA2The respectively value of two modulating waves of A phases；CPB1、CPB2The respectively value of two modulating waves of B phases；
CPC1、CPC2The respectively value of two modulating waves of C phases；CNT is the peak value of triangular carrier.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101340156A (en) * | 2008-08-07 | 2009-01-07 | 株洲南车时代电气股份有限公司 | Modulating method and system of 3 level space vector |
| JP2010206931A (en) * | 2009-03-03 | 2010-09-16 | Fuji Electric Systems Co Ltd | Method and device for control of three-level inverter |
| CN104038091A (en) * | 2014-07-04 | 2014-09-10 | 国家电网公司 | Three-level converter direct-current side neutral-point voltage balance control method based on SVPWM |
| CN104578816A (en) * | 2014-12-23 | 2015-04-29 | 西安交通大学 | Clamp five-level back-to-back converter with flying capacitor auxiliary bridge arms |
-
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101340156A (en) * | 2008-08-07 | 2009-01-07 | 株洲南车时代电气股份有限公司 | Modulating method and system of 3 level space vector |
| JP2010206931A (en) * | 2009-03-03 | 2010-09-16 | Fuji Electric Systems Co Ltd | Method and device for control of three-level inverter |
| CN104038091A (en) * | 2014-07-04 | 2014-09-10 | 国家电网公司 | Three-level converter direct-current side neutral-point voltage balance control method based on SVPWM |
| CN104578816A (en) * | 2014-12-23 | 2015-04-29 | 西安交通大学 | Clamp five-level back-to-back converter with flying capacitor auxiliary bridge arms |
Non-Patent Citations (2)
| Title |
|---|
| A space vector PWM modulation scheme for back-to-back three-level diode-clamped converters;GRIOGOLETTO F B等;《COBEP》;20091001;第1058-1065页 * |
| 三电平双PWM变换器电容电压平衡综合控制;范必双等;《电机与控制学报》;20140131;第18卷(第1期);第38-43页 * |
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