CN107370410A - Cascaded H-bridges inverter control method and control device - Google Patents

Cascaded H-bridges inverter control method and control device Download PDF

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Publication number
CN107370410A
CN107370410A CN201710625980.8A CN201710625980A CN107370410A CN 107370410 A CN107370410 A CN 107370410A CN 201710625980 A CN201710625980 A CN 201710625980A CN 107370410 A CN107370410 A CN 107370410A
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bridge
mrow
msub
bridge modules
triple
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CN107370410B (en
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赵涛
王新宇
徐君
张兴
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Sungrow Power Supply Co Ltd
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Sungrow Power Supply Co Ltd
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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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac 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
    • H02M7/537—Conversion of dc power input into ac 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, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac 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, e.g. single switched pulse inverters in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • 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
    • H02M1/32—Means for protecting converters other than automatic disconnection

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

This application discloses cascaded H-bridges inverter control method and control device, this method includes：Identify the H bridge modules of ovennodulation in Cascade H bridge inverter and the H bridge modules of non-ovennodulation；The triple-frequency harmonics of the H bridge modules compensation positive of respectively each ovennodulation, compensation rate are defined by the modulation wave amplitude for ensureing this H bridge modules equal to 1；The H bridge modules of respectively each not ovennodulation compensate anti-phase triple-frequency harmonics, compensation rate with ensure the modulation wave amplitude of this H bridge modules be no more than 1, and total compensation rate that total compensation rate of the H bridge modules of all not ovennodulations is equal to the H bridge modules of all ovennodulations is defined, so as to suppress each H bridge modules ovennodulation in Cascade H bridge inverter.

Description

Cascaded H-bridges inverter control method and control device
Technical field
The present invention relates to technical field of photovoltaic power generation, more specifically to cascaded H-bridges inverter control method and control Device.
Background technology
The topological structure of Cascade H bridge inverter is as shown in figure 1, including multiple H bridge modules, the input of each H bridge modules terminates Independent photovoltaic module, output end series connection.The Cascade H bridge inverter is approximately using sinusoidal pulse width modulation strategy output waveform The alternating current of sine wave, and it is sent into power network.
In practical application, when having shadow occlusion or other reasonses cause some output power of photovoltaic module to decline, it is defeated Going out the output voltage of H bridge modules corresponding to the normal photovoltaic module of power can increase, and modulation degree can also increase, or even occur Ovennodulation, so as to cause power network current degradation even system unstable.
How effectively to solve the problems, such as H bridge module ovennodulations, be the key for improving cascaded H-bridges combining inverter performance.
The content of the invention
In view of this, it is inverse to suppress cascaded H-bridges the invention provides cascaded H-bridges inverter control method and control device Each H bridge modules ovennodulation become in device.
A kind of cascaded H-bridges inverter control method, including：
Identify the H bridge modules of ovennodulation in Cascade H bridge inverter and the H bridge modules of non-ovennodulation；
The triple-frequency harmonics of the H bridge modules compensation positive of respectively each ovennodulation, compensation rate is to ensure the tune of this H bridge modules Wave amplitude processed is defined equal to 1；
The H bridge modules of respectively each not ovennodulation compensate anti-phase triple-frequency harmonics, and compensation rate is to ensure this H bridge modules Modulate wave amplitude and be no more than 1, and total compensation rate of the H bridge modules of all not ovennodulations is equal to the H bridge modules of all ovennodulations Total compensation rate be defined.
Wherein, the 1st in the Cascade H bridge inverter, 2 ..., x H bridge module is the H bridge modules of ovennodulation, xth+ 1st ..., n H bridge module is the H bridge modules of not ovennodulation；
The triple-frequency harmonics of the H bridge modules compensation positive for being respectively each ovennodulation, compensation rate is to ensure this H bridge modules Modulation wave amplitude be defined equal to 1, including：
Obtain the modulation degree S of i-th of H bridge modulei, i=1,2 ..., x；
According to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, as i-th of H bridge module three times Harmonic compensation coefficient；Wherein, the curve C2It is that any one H bridge module is modulating wave amplitude as 1 in Cascade H bridge inverter When, curve that modulation degree changes with triple-frequency harmonics penalty coefficient；
According to SiAnd ki, obtain the modulating wave m of i-th of H bridge moduleiFor
mi=Si×sin(θ+θr)+kiSi×sin(3θ+θr)
In formula, θ is electric network voltage phase angle, θrFor total modulation voltage and the difference at electric network voltage phase angle.
Wherein, it is described according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, including：Using tabling look-up Method, according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei。
It is or described according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, including：Utilize curve Fitting process, according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei。
Wherein, described is respectively that the H bridge modules of each not ovennodulation compensate anti-phase triple-frequency harmonics, and compensation rate is to ensure this The modulation wave amplitude of H bridge modules is no more than 1, and total compensation rate of the H bridge modules of all not ovennodulations is equal to all ovennodulations Total compensation rates of H bridge modules be defined, including：
Calculate the amplitude V for total third harmonic voltage that the H bridge modules of all ovennodulations are compensatedT3For：
In formula, VdciFor the DC voltage of i-th of H bridge module；
Calculating j-th of H bridge module allows the maximum voltage amplitude V of compensationdcj(max) it is：
Vdcj(max)=Vdcj-SjVdcj
In formula, VdcjFor the DC voltage of j-th of H bridge module, j=x+1 ..., n；
Calculate the third harmonic voltage amplitude V that j-th of H bridge module is compensatedcjWith penalty coefficient kjFor
Vcj=VT3/Vdcj
According to VcjAnd kjThe modulating wave m of j-th of H bridge module is calculatedjFor
mj=Sj×sin(θ+θr)+kjVcj×sin(3θ+θr)。
A kind of cascaded H-bridges control device for inverter, including：
Recognition unit, for identifying the H bridge modules of ovennodulation in Cascade H bridge inverter and the H bridge modules of non-ovennodulation；
First compensating unit, for be respectively each ovennodulation H bridge modules compensation positive triple-frequency harmonics, compensation rate with Ensure that the modulation wave amplitude of this H bridge modules is defined equal to 1；
Second compensating unit, the H bridge modules for being respectively each not ovennodulation compensate anti-phase triple-frequency harmonics, compensation rate To ensure that the modulation wave amplitude of this H bridge modules is no more than 1, and total compensation rate of the H bridge modules of all not ovennodulations is equal to institute The total compensation rate for having the H bridge modules of ovennodulation is defined.
Wherein, the 1st in the Cascade H bridge inverter, 2 ..., x H bridge module is the H bridge modules of ovennodulation, xth+ 1st ..., n H bridge module is the H bridge modules of not ovennodulation；
First compensating unit is specifically used for the modulation degree S for obtaining i-th of H bridge modulei, i=1,2 ..., x；According to song Line C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, the triple-frequency harmonics penalty coefficient as i-th of H bridge module；Its In, the curve C2It is that for any one H bridge module when it is 1 to modulate wave amplitude, modulation degree is with humorous three times in Cascade H bridge inverter The curve of ripple penalty coefficient change；According to SiAnd ki, obtain the modulating wave m of i-th of H bridge moduleiFor
mi=Si×sin(θ+θr)+kiSi×sin(3θ+θr)
In formula, θ is electric network voltage phase angle, θrFor total modulation voltage and the difference at electric network voltage phase angle.
Wherein, first compensating unit uses look-up table, according to curve C2Obtain and SiTriple-frequency harmonics is mended corresponding to unique Repay coefficient ki。
Or first compensating unit uses curve-fitting method, according to curve C2Obtain and SiIt is humorous three times corresponding to unique Ripple penalty coefficient ki。
Wherein, second compensating unit be specifically used for calculating the H bridge modules of all ovennodulations are compensated it is total three times The amplitude V of harmonic voltageT3For：
In formula, VdciFor the DC voltage of i-th of H bridge module；
Calculating j-th of H bridge module allows the maximum voltage amplitude V of compensationdcj(max) it is：
Vdcj(max)=Vdcj-SjVdcj
In formula, VdcjFor the DC voltage of j-th of H bridge module, j=x+1 ..., n；
Calculate the third harmonic voltage amplitude V that j-th of H bridge module is compensatedcjWith penalty coefficient kjFor
Vcj=VT3/Vdcj
According to VcjAnd kjThe modulating wave m of j-th of H bridge module is calculatedjFor
mj=Sj×sin(θ+θr)+kjVcj×sin(3θ+θr)。
It can be seen from the above technical scheme that the present invention compensates the humorous three times of positive by the H bridge modules to ovennodulation Ripple, it is 1 it is modulated wave amplitude, while in order that all total output voltages of H bridge modules do not contain third-harmonic component, it is necessary to mend Repay the anti-phase triple-frequency harmonics of equivalent and be reasonably allocated to the H bridge modules of not ovennodulation, finally ensure all H bridge modules not tonings System.
Brief description of the drawings
In order to illustrate more clearly about the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing There is the required accompanying drawing used in technology description to be briefly described, it should be apparent that, drawings in the following description are only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, can be with Other accompanying drawings are obtained according to these accompanying drawings.
Fig. 1 is a kind of cascaded H-bridges inverter topology schematic diagram disclosed in prior art；
Fig. 2 is a kind of cascaded H-bridges inverter control method flow chart disclosed in the embodiment of the present invention；
Fig. 3 is the modulating wave waved surface figure of H bridge modules；
Fig. 4 is Fig. 3 X-Z views；
Fig. 5 is the forward and backward oscillogram of the triple-frequency harmonics of the H bridge modules compensation positive of certain ovennodulation；
Fig. 6 is that the H bridge modules of certain not ovennodulation compensate the forward and backward oscillogram of anti-phase triple-frequency harmonics；
Fig. 7 is the method flow diagram for the triple-frequency harmonics that positive is compensated to the H bridge modules of ovennodulation；
Fig. 8 is max (v of the H bridge modules in S=1r)-k curve maps, and in max (vrS-k curve maps during)=1；
Fig. 9 is the method flow diagram that anti-phase triple-frequency harmonics is compensated to the H bridge modules of not ovennodulation；
Figure 10 is a kind of cascaded H-bridges control device for inverter structural representation disclosed in the embodiment of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Site preparation describes, it is clear that described embodiment is only part of the embodiment of the present invention, rather than whole embodiments.It is based on Embodiment in the present invention, those of ordinary skill in the art are obtained every other under the premise of creative work is not made Embodiment, belong to the scope of protection of the invention.
Referring to Fig. 2, the embodiment of the invention discloses a kind of cascaded H-bridges inverter control method, including：
Step S01：Identify the H bridge modules of ovennodulation in Cascade H bridge inverter and the H bridge modules of non-ovennodulation.
Specifically, the H bridge modules of so-called ovennodulation, refer to modulate the H bridge modules that wave amplitude is more than carrier amplitude.It is so-called not The H bridge modules of ovennodulation, refer to modulate the H bridge modules that wave amplitude is not more than carrier amplitude.By the modulating wave for comparing H bridge modules The size of amplitude and carrier amplitude, you can identify the H bridge modules whether ovennodulation.
Step S02：The triple-frequency harmonics of the H bridge modules compensation positive of respectively each ovennodulation, compensation rate is to ensure this H bridges The modulation wave amplitude of module is defined equal to 1；
Step S03：The H bridge modules of respectively each not ovennodulation compensate anti-phase triple-frequency harmonics, and compensation rate is to ensure this H The modulation wave amplitude of bridge module is no more than 1, and total compensation rate of the H bridge modules of all not ovennodulations is equal to all ovennodulations Total compensation rate of H bridge modules is defined.
The present embodiment is to suppress each H bridge modules ovennodulation in Cascade H bridge inverter using triple-frequency harmonics method is injected.For The technical scheme of clearer description the present embodiment, below its operation principle is described in detail.
The output voltage of Cascade H bridge inverter is free of third-harmonic component, any one H bridge mould in Cascade H bridge inverter The output voltage of block is also free of third-harmonic component.Any one H bridge module compensates triple-frequency harmonics in Cascade H bridge inverter Afterwards, the modulating wave v of this H bridge modulesrFor
vr=S × sin (wt)+kS × sin (3wt) (1)
In formula, S is the modulation degree of this H bridge modules, and k is that the triple-frequency harmonics penalty coefficient of this H bridge modules (compensates during k ＞ 0 It is the triple-frequency harmonics of positive, what is compensated during k ＜ 0 is anti-phase triple-frequency harmonics；| k | bigger, compensation rate is bigger), w is angular frequency Rate, t are the time.
For formula (1), S=1 is kept, v is drawn out with MATLABrThe surface chart such as Fig. 3 institutes changed with variable wt and k Show.Fig. 3 X-Z views are as shown in figure 4, Fig. 4 longitudinal axis is the equal of the modulation wave amplitude max (v of this H bridge modulesr)。
As shown in Figure 4,0≤k≤1/6 is monotone decreasing region, that is to say, that：H bridge modules compensation to ovennodulation is certain The triple-frequency harmonics of positive is measured, the modulation wave amplitude max (v of this H bridge modules can be reducedr), so as to suppress this H to a certain extent Bridge module ovennodulation；Moreover, during k=1/6, max (vr) reach minimum, this H bridge module ovennodulations can be suppressed to greatest extent.
Moreover, also known by Fig. 4, during k ＜ 0, the modulation wave amplitude max (v of this H bridge modulesr) ＞ 1, and k ＜ 0 are single Adjust incremental zone, that is to say, that：A certain amount of anti-phase triple-frequency harmonics is compensated to H bridge modules, the H bridge modules of not ovennodulation can be increased The risk of ovennodulation；Moreover, the compensation rate of anti-phase triple-frequency harmonics is bigger, got over not the risk of the H bridge module ovennodulations of ovennodulation It is high.
Analyzed more than, when some H bridge modules ovennodulations in Cascade H bridge inverter, pass through the H bridges to ovennodulation The triple-frequency harmonics of a certain amount of positive of module for compensating, these H bridge module ovennodulations can be suppressed to a certain extent.But due to cascade Third-harmonic component should not be contained in the output voltage of H bridge inverters, so a certain amount of in the H bridge modules compensation to ovennodulation While the triple-frequency harmonics of positive, it is also necessary to which the H bridge modules to not ovennodulation compensate a certain amount of anti-phase triple-frequency harmonics, and institute The total compensation rate for having the anti-phase triple-frequency harmonics of the H bridge modules of not ovennodulation should be equal to the positive of the H bridge modules of all ovennodulations Total compensation rate of triple-frequency harmonics, it so just can guarantee that compensation is mutually supported to the positive and negative phase triple-frequency harmonics in Cascade H bridge inverter Disappear, so that all total output voltages of H bridge modules, namely the output voltage of Cascade H bridge inverter are free of third-harmonic component.
And it should be noted that when the H bridge modules to ovennodulation compensate the triple-frequency harmonics of positive, it is impossible to pursue simply Suppress this H bridge modules ovennodulation (k=1/6 is set) to greatest extent, but should be according to power output between each H bridge modules Uneven degree, reasonable compensation, compensate to the modulation wave amplitude of the H bridge modules of ovennodulation and be down to 1, so as to reduce not toning There is the risk of ovennodulation because of the anti-phase triple-frequency harmonics of compensation equivalent in the H bridge modules of system.
For example, by taking two H bridge modules as an example, it is assumed that the modulation wavelength-division of first H bridge module and second H bridge module Not as shown in formula (2) and formula (3).
vr1=1.1sin (wt) (2)
vr2=0.85sin (wt) (3)
It is obvious that first H bridge module ovennodulation, second H bridge module not ovennodulation.To solve first H bridge module The problem of ovennodulation, the maximum amount of positive triple-frequency harmonics is compensated to first H bridge module, while in order to ensure that two H bridge modules are total Output voltage be free of triple-frequency harmonics, the triple-frequency harmonics anti-phase to second H bridge module compensation equivalent, after the compensation of two H bridge modules Modulating wave respectively as shown in formula (4) and formula (5).
y1=1.1sin (wt)+1.1/6*sin (3wt) (4)
y2=0.85sin (wt) -1.1/6*sin (3wt) (5)
According to formula (2) and formula (4) draw out first H bridge module compensate forward and backward modulating wave oscillogram as shown in figure 5, It is as shown in Figure 6 that second forward and backward modulating wave oscillogram of H bridge modules compensation is drawn out according to formula (3) and formula (5).By Fig. 5 and figure 6 understand, the modulation wave amplitude after first H bridge modules compensation is less than 1, solves the problems, such as first H bridge module ovennodulation, but Modulation wave amplitude after second H bridge modules compensation is more than 1, generates new ovennodulation problem, and this compensates humorous three times with us The original intention of ripple is disagreed.
Observe Fig. 5 to understand, have certain allowance between the modulation wave amplitude and 1 after first H bridge modules compensation, if Suitably reduce the triple-frequency harmonics penalty coefficient k of first H bridge module, be only to compensate first H bridge module to modulation wave amplitude For 1, then both can guarantee that first H bridge module not ovennodulation, and can reduces the risk of second H bridge module ovennodulation.
So for the Cascade H bridge inverter containing n H bridge module, it is assumed that some time has inscribed x H bridge module toning System, for ease of description, the numbering for defining the H bridge modules of this x ovennodulation is followed successively by 1,2 ..., x, while it is individual to define remaining n-x Not the numbering of the H bridge modules of ovennodulation be followed successively by x+1 ..., n.To i-th (i=1,2 ..., x) individual H bridge modules compensate positive During triple-frequency harmonics, compensation rate is to ensure that the modulation wave amplitude of i-th of H bridge module is defined (i.e. described step S02) equal to 1；Meanwhile The H bridge modules of respectively each not ovennodulation compensate anti-phase triple-frequency harmonics, and compensation rate is to ensure the modulation wave amplitude of this H bridge modules Value is no more than 1, and the compensation rate summation of the H bridge modules of all not ovennodulations is equal to the compensation of the H bridge modules of all ovennodulations Amount summation is defined (i.e. described step S03).
The specific implementation of the step S02 as shown in fig. 7, comprises：
Step S021：Obtain i-th (i=1,2 ..., x) individual H bridge modules modulation degree Si；
Step S022：According to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, as i-th of H bridge mould The triple-frequency harmonics penalty coefficient of block；Wherein, the curve C2Be in Cascade H bridge inverter any one H bridge module in modulating wave Amplitude max (vr) when being 1, curve that modulation degree S changes with triple-frequency harmonics penalty coefficient k.
Specifically, for any one H bridge module in Cascade H bridge inverter, S=1 is kept, according to formula (1) Draw out the modulation wave amplitude max (v of the H bridge modulesr) with the curve of k changes, such as curve C in Fig. 81It is shown；According to curve C1Can To draw out modulation wave amplitude max (vr) when being 1, curve that S changes with k, such as curve C in Fig. 82It is shown.As seen from Figure 8, In the region of 0≤k≤1/6, S and k is corresponded, and S span is 1~1.155.
For i-th of H bridge module, according to curve C2It can find and modulation degree SiTriple-frequency harmonics compensation system corresponding to unique Number ki, can specifically use look-up table or curve-fitting method is found and SiK corresponding to uniquei。
The look-up table, refer to according to curve C2, in the section of 0≤k≤1/6, several suitable points are chosen, in actual system During system operation, by calculating the modulation wave amplitude of i-th of H bridge module, choose and its closest approach, you can corresponding to calculating kiValue.
The curve-fitting method, refer to according to curve C2Draw out max (vr) be 1 when, k passes through choosing with S change curve A series of suitable points are taken, fit S and k mathematic(al) representation.When real system is run, by the modulating wave of i-th of H bridge module Amplitude substitutes into the mathematic(al) representation, you can calculates corresponding kiValue.
Step S023：According to SiAnd ki, obtain the modulating wave m of i-th of H bridge moduleiFor
mi=Si×sin(θ+θr)+kiSi×sin(3θ+θr)
In formula, θ is electric network voltage phase angle, θrFor total modulation voltage and the difference at electric network voltage phase angle.
Total compensation rate of anti-phase triple-frequency harmonics is reasonably allocated to the H bridge modules of each not ovennodulation by the step S03, protects Card compensate anti-phase triple-frequency harmonics H bridge modules will not ovennodulation, distribution method as shown in figure 9, including：
Step S301：Calculate the amplitude V for total third harmonic voltage that the H bridge modules of all ovennodulations are compensatedT3For：
In formula, VdciFor the DC voltage of i-th of H bridge module.
Step S302：Calculate the maximum voltage amplitude V that the individual H bridge modules of jth (j=x+1 ..., n) allow to compensatedcj (max) it is：
Vdcj(max)=Vdcj-SjVdcj (7)
In formula, VdcjFor the DC voltage of j-th of H bridge module.
Step S303：Calculate the third harmonic voltage amplitude V that j-th of H bridge module is compensatedcjWith penalty coefficient kjFor
Vcj=VT3/Vdcj (8)
Step S304：The modulating wave m of j-th of H bridge module is calculated according to formula (8) and formula (9)jFor
mi=Sj×sin(θ+θr)+kjVcj×sin(3θ+θr) (10)
Seen from the above description, the present embodiment makes its tune by the triple-frequency harmonics of the H bridge modules compensation positive to ovennodulation Wave amplitude processed is 1, while in order that all total output voltages of H bridge modules do not contain third-harmonic component, it is necessary to which to compensate equivalent anti- The triple-frequency harmonics of phase and the H bridge modules for being reasonably allocated to not ovennodulation, finally ensure all H bridge modules not ovennodulations.
In addition, referring to Figure 10, the embodiment of the invention discloses a kind of cascaded H-bridges control device for inverter, including：
Recognition unit 100, for identifying the H bridge modules of ovennodulation in Cascade H bridge inverter and the H bridge moulds of non-ovennodulation Block；
First compensating unit 200, for being respectively that the H bridge modules of each ovennodulation compensate the triple-frequency harmonics of positive, compensation Amount is defined by the modulation wave amplitude for ensureing this H bridge modules equal to 1；
Second compensating unit 300, the H bridge modules for being respectively each not ovennodulation compensate anti-phase triple-frequency harmonics, mended The amount of repaying is to ensure the modulation wave amplitude of this H bridge modules no more than 1, and total compensation rate of H bridge modules of all not ovennodulations etc. It is defined in total compensation rate of the H bridge modules of all ovennodulations.
Wherein, the 1st in the Cascade H bridge inverter, 2 ..., x H bridge module is the H bridge modules of ovennodulation, xth+ 1st ..., n H bridge module is the H bridge modules of not ovennodulation；
First compensating unit 200 is specifically used for the modulation degree S for obtaining i-th of H bridge modulei, i=1,2 ..., x；According to song Line C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, the triple-frequency harmonics penalty coefficient as i-th of H bridge module；Its In, the curve C2It is that for any one H bridge module when it is 1 to modulate wave amplitude, modulation degree is with humorous three times in Cascade H bridge inverter The curve of ripple penalty coefficient change；According to SiAnd ki, obtain the modulating wave m of i-th of H bridge moduleiFor
mi=Si×sin(θ+θr)+kiSi×sin(3θ+θr)
In formula, θ is electric network voltage phase angle, θrFor total modulation voltage and the difference at electric network voltage phase angle.
Wherein, the first compensating unit 200 uses look-up table, according to curve C2Obtain and SiTriple-frequency harmonics is mended corresponding to unique Repay coefficient ki。
Or first compensating unit 200 use curve-fitting method, according to curve C2Obtain and SiIt is humorous three times corresponding to unique Ripple penalty coefficient ki。
Wherein, the second compensating unit 300 is specifically used for calculating that the H bridge modules of all ovennodulations are compensated is total humorous three times The amplitude V of wave voltageT3For：
In formula, VdciFor the DC voltage of i-th of H bridge module；
Calculating j-th of H bridge module allows the maximum voltage amplitude V of compensationdcj(max) it is：
Vdcj(max)=Vdcj-SjVdcj
In formula, VdcjFor the DC voltage of j-th of H bridge module, j=x+1 ..., n；
Calculate the third harmonic voltage amplitude V that j-th of H bridge module is compensatedcjWith penalty coefficient kjFor
Vcj=VT3/Vdcj
According to VcjAnd kjThe modulating wave m of j-th of H bridge module is calculatedjFor
mj=Sj×sin(θ+θr)+kjVcj×sin(3θ+θr)。
In summary, the present invention makes its modulate wave amplitude by the triple-frequency harmonics of the H bridge modules compensation positive to ovennodulation For 1, while in order that all total output voltages of H bridge modules do not contain third-harmonic component, it is necessary to which to compensate equivalent anti-phase three times Harmonic wave and the H bridge modules for being reasonably allocated to not ovennodulation, finally ensure all H bridge modules not ovennodulations.
Each embodiment is described by the way of progressive in this specification, what each embodiment stressed be and other The difference of embodiment, between each embodiment identical similar portion mutually referring to.For device disclosed in embodiment For, because it is corresponded to the method disclosed in Example, so description is fairly simple, related part is said referring to method part It is bright.
Herein, such as first and second or the like relational terms be used merely to by an entity or operation with it is another One entity or operation make a distinction, and not necessarily require or imply between these entities or operation any this reality be present Relation or order.
The foregoing description of the disclosed embodiments, professional and technical personnel in the field are enable to realize or using the present invention. A variety of modifications to these embodiments will be apparent for those skilled in the art, as defined herein General Principle can be realized in other embodiments in the case where not departing from the spirit or scope of the embodiment of the present invention.Therefore, The embodiment of the present invention is not intended to be limited to the embodiments shown herein, and be to fit to principles disclosed herein and The consistent most wide scope of features of novelty.

Claims (10)

  1. A kind of 1. cascaded H-bridges inverter control method, it is characterised in that including：
    Identify the H bridge modules of ovennodulation in Cascade H bridge inverter and the H bridge modules of non-ovennodulation；
    The triple-frequency harmonics of the H bridge modules compensation positive of respectively each ovennodulation, compensation rate is to ensure the modulating wave of this H bridge modules Amplitude is defined equal to 1；
    The H bridge modules of respectively each not ovennodulation compensate anti-phase triple-frequency harmonics, and compensation rate is to ensure the modulation of this H bridge modules Wave amplitude is no more than 1, and total compensation rate of the H bridge modules of all not ovennodulations is equal to the total of the H bridge modules of all ovennodulations Compensation rate is defined.
  2. 2. cascaded H-bridges inverter control method according to claim 1, it is characterised in that in the Cascade H bridge inverter 1st, 2 ..., x H bridge module be ovennodulation H bridge modules, (x+1)th ..., n H bridge module be not ovennodulation H bridge modules；
    The triple-frequency harmonics of the H bridge modules compensation positive for being respectively each ovennodulation, compensation rate is to ensure the tune of this H bridge modules Wave amplitude processed is defined equal to 1, including：
    Obtain the modulation degree S of i-th of H bridge modulei, i=1,2 ..., x；
    According to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, the triple-frequency harmonics as i-th of H bridge module Penalty coefficient；Wherein, the curve C2It is that any one H bridge module when it is 1 to modulate wave amplitude, is adjusted in Cascade H bridge inverter The curve that system changes with triple-frequency harmonics penalty coefficient；
    According to SiAnd ki, obtain the modulating wave m of i-th of H bridge moduleiFor
    mi=Si×sin(θ+θr)+kiSi×sin(3θ+θr)
    In formula, θ is electric network voltage phase angle, θrFor total modulation voltage and the difference at electric network voltage phase angle.
  3. 3. cascaded H-bridges inverter control method according to claim 2, it is characterised in that described according to curve C2Obtain with SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, including：
    Using look-up table, according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei。
  4. 4. cascaded H-bridges inverter control method according to claim 2, it is characterised in that described according to curve C2Obtain with SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, including：
    Using curve-fitting method, according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei。
  5. 5. cascaded H-bridges inverter control method according to claim 2, it is characterised in that it is described be respectively it is each only The H bridge modules of modulation compensate anti-phase triple-frequency harmonics, and compensation rate is no more than 1 to ensure the modulation wave amplitude of this H bridge modules, and Total compensation rate that total compensation rate of the H bridge modules of all not ovennodulations is equal to the H bridge modules of all ovennodulations is defined, including：
    Calculate the amplitude V for total third harmonic voltage that the H bridge modules of all ovennodulations are compensatedT3For：
    <mrow> <msub> <mi>V</mi> <mrow> <mi>T</mi> <mn>3</mn> </mrow> </msub> <mo>=</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>x</mi> </munderover> <msub> <mi>k</mi> <mi>i</mi> </msub> <msub> <mi>S</mi> <mi>i</mi> </msub> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>c</mi> <mi>i</mi> </mrow> </msub> </mrow>
    In formula, VdciFor the DC voltage of i-th of H bridge module；
    Calculating j-th of H bridge module allows the maximum voltage amplitude V of compensationdcj(max) it is：
    Vdcj(max)=Vdcj-SjVdcj
    In formula, VdcjFor the DC voltage of j-th of H bridge module, j=x+1 ..., n；
    Calculate the third harmonic voltage amplitude V that j-th of H bridge module is compensatedcjWith penalty coefficient kjFor
    Vcj=VT3/Vdcj
    <mrow> <msub> <mi>k</mi> <mi>j</mi> </msub> <mo>=</mo> <mo>-</mo> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>c</mi> <mi>j</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>m</mi> <mi>a</mi> <mi>x</mi> <mo>)</mo> </mrow> <mo>/</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>q</mi> <mo>=</mo> <mi>x</mi> <mo>+</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>c</mi> <mi>q</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>m</mi> <mi>a</mi> <mi>x</mi> <mo>)</mo> </mrow> </mrow>
    According to VcjAnd kjThe modulating wave m of j-th of H bridge module is calculatedjFor
    mj=Sj×sin(θ+θr)+kjVcj×sin(3θ+θr)。
  6. A kind of 6. cascaded H-bridges control device for inverter, it is characterised in that including：
    Recognition unit, for identifying the H bridge modules of ovennodulation in Cascade H bridge inverter and the H bridge modules of non-ovennodulation；
    First compensating unit, for be respectively each ovennodulation H bridge modules compensation positive triple-frequency harmonics, compensation rate is to ensure The modulation wave amplitude of this H bridge modules is defined equal to 1；
    Second compensating unit, for being respectively that the H bridge modules of each not ovennodulation compensate anti-phase triple-frequency harmonics, compensation rate is to protect The modulation wave amplitude for demonstrate,proving this H bridge modules is no more than 1, and total compensation rate of the H bridge modules of all not ovennodulations is equal to all mistakes Total compensation rate of the H bridge modules of modulation is defined.
  7. 7. cascaded H-bridges control device for inverter according to claim 6, it is characterised in that in the Cascade H bridge inverter 1st, 2 ..., x H bridge module be ovennodulation H bridge modules, (x+1)th ..., n H bridge module be not ovennodulation H bridge modules；
    First compensating unit is specifically used for the modulation degree S for obtaining i-th of H bridge modulei, i=1,2 ..., x；According to curve C2 Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei, the triple-frequency harmonics penalty coefficient as i-th of H bridge module；Wherein, The curve C2It is that for any one H bridge module when it is 1 to modulate wave amplitude, modulation degree is with triple-frequency harmonics in Cascade H bridge inverter The curve of penalty coefficient change；According to SiAnd ki, obtain the modulating wave m of i-th of H bridge moduleiFor
    mi=Si×sin(θ+θr)+kiSi×sin(3θ+θr)
    In formula, θ is electric network voltage phase angle, θrFor total modulation voltage and the difference at electric network voltage phase angle.
  8. 8. cascaded H-bridges control device for inverter according to claim 7, it is characterised in that first compensating unit is adopted With look-up table, according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei。
  9. 9. cascaded H-bridges control device for inverter according to claim 7, it is characterised in that first compensating unit is adopted With curve-fitting method, according to curve C2Obtain and SiTriple-frequency harmonics penalty coefficient k corresponding to uniquei。
  10. 10. cascaded H-bridges control device for inverter according to claim 7, it is characterised in that the second compensating unit tool The amplitude V for total third harmonic voltage that body is compensated for calculating the H bridge modules of all ovennodulationsT3For：
    <mrow> <msub> <mi>V</mi> <mrow> <mi>T</mi> <mn>3</mn> </mrow> </msub> <mo>=</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>x</mi> </munderover> <msub> <mi>k</mi> <mi>i</mi> </msub> <msub> <mi>S</mi> <mi>i</mi> </msub> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>c</mi> <mi>i</mi> </mrow> </msub> </mrow>
    In formula, VdciFor the DC voltage of i-th of H bridge module；
    Calculating j-th of H bridge module allows the maximum voltage amplitude V of compensationdcj(max) it is：
    Vdcj(max)=Vdcj-SjVdcj
    In formula, VdcjFor the DC voltage of j-th of H bridge module, j=x+1 ..., n；
    Calculate the third harmonic voltage amplitude V that j-th of H bridge module is compensatedcjWith penalty coefficient kjFor
    Vcj=VT3/Vdcj
    <mrow> <msub> <mi>k</mi> <mi>j</mi> </msub> <mo>=</mo> <mo>-</mo> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>c</mi> <mi>j</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>m</mi> <mi>a</mi> <mi>x</mi> <mo>)</mo> </mrow> <mo>/</mo> <munderover> <mo>&amp;Sigma;</mo> <mrow> <mi>q</mi> <mo>=</mo> <mi>x</mi> <mo>+</mo> <mn>1</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>V</mi> <mrow> <mi>d</mi> <mi>c</mi> <mi>q</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>m</mi> <mi>a</mi> <mi>x</mi> <mo>)</mo> </mrow> </mrow>
    According to VcjAnd kjThe modulating wave m of j-th of H bridge module is calculatedjFor
    mj=Sj×sin(θ+θr)+kjVcj×sin(3θ+θr)。
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CN108429476A (en) * 2018-03-28 2018-08-21 阳光电源股份有限公司 A kind of control method and controller of Cascade H bridge inverter
CN108599609A (en) * 2018-05-14 2018-09-28 合肥博鳌电气科技有限公司 A kind of improvement phase-shifting carrier wave modulator approach based on three module-cascade H bridges
CN109066699A (en) * 2018-09-04 2018-12-21 兰州理工大学 A method of judging that ovennodulation influences micro-source inverter series connection micro-capacitance sensor voltage

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CN105790302A (en) * 2016-04-11 2016-07-20 阳光电源股份有限公司 Cascade type photovoltaic grid-connected inverter and control method thereof and control device thereof
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CN101615860A (en) * 2009-07-23 2009-12-30 东南大学 Be applied to a kind of modulator approach of cascade converter
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CN105790302A (en) * 2016-04-11 2016-07-20 阳光电源股份有限公司 Cascade type photovoltaic grid-connected inverter and control method thereof and control device thereof
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CN108429476A (en) * 2018-03-28 2018-08-21 阳光电源股份有限公司 A kind of control method and controller of Cascade H bridge inverter
CN108599609A (en) * 2018-05-14 2018-09-28 合肥博鳌电气科技有限公司 A kind of improvement phase-shifting carrier wave modulator approach based on three module-cascade H bridges
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CN109066699A (en) * 2018-09-04 2018-12-21 兰州理工大学 A method of judging that ovennodulation influences micro-source inverter series connection micro-capacitance sensor voltage
CN109066699B (en) * 2018-09-04 2021-11-02 兰州理工大学 Method for judging influence of overmodulation on micro-source inverter series micro-grid voltage

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