CN105226712A - A kind of control method and system regulating inversion system output voltage - Google Patents

Abstract

The invention discloses a kind of control method and the system that regulate inversion system output voltage, inversion system comprises N number of alternating current source module, when i-th alternating current source module is in power self-balancing pattern, comprises the DC source in disconnection i-th alternating current source module; The DC voltage controlling the DCAC module in i-th alternating current source module is the first predeterminated voltage; Generate modulating wave, the sub-voltage making i-th alternating current source module export when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports compensates total voltage, to make the output voltage of inversion system meet the second predeterminated voltage, and the power that modulating wave makes i-th alternating current source module exchange with inversion system in one-period is 0; According to modulating wave and the first predeterminated voltage, i-th alternating current source module is controlled.The invention enables i-th alternating current source module of power self-balancing pattern can support total output voltage and can ensure this modular power self-balancing again, improve the efficiency of inversion system.

Description

A kind of control method and system regulating inversion system output voltage

Technical field

The present invention relates to Inversion Control System technical field, particularly relate to a kind of control method and the system that regulate inversion system output voltage.

Background technology

Cascade multilevel converter (CascadedMultilevelConverters, CMC) multiple grid-connected workplace can be applicable to, please refer to Fig. 1 and Fig. 2, wherein, Fig. 1 is the structural representation of a kind of cascade multilevel converter provided by the invention, Fig. 2 is the structural representation of a kind of alternating current source module provided by the invention, cascade multilevel converter comprises alternating current source module that n connects successively and 1 total filter, alternating current source module comprises DC source and DCAC module, when cascade multilevel converter is used in the application occasion needing to exchange active power, if the DC source of certain the alternating current source module in cascade multilevel converter cannot active power of output time, the DC source of this alternating current source module is then needed to disconnect, and under making this alternating current source module run on new operating mode, make it can support output voltage and can ensure again modular power self-balancing (PowerSelf-balanced, PSB).

Concrete, when cascade multilevel converter applies to photovoltaic generating system, often exist certain DCAC module connect PV plate due to damage or open circuit voltage too low and can not active power of output, and total output voltage demand of inversion system is higher again and cause this module not allow situation about being bypassed, this will cause system cannot normally work due to undermodulation.For addressing this problem in prior art, usually have following two kinds of methods, one is chosen as cascade multilevel converter to increase redundancy submodule, but when this way can cause inversion system normally to work, the modulation ratio of each alternating current source module is too low, affects inversion system whole efficiency; Another kind method allows the PV plate boosting of some alternating current source module depart from maximum power point (MaximumPowerPoint, MPP), but do like this and can lose energy output.

Therefore, how to provide a kind of to make the alternating current source module being in power self-balancing pattern can support output voltage can to ensure that again the control method of modular power self-balancing and system are the problems that those skilled in the art need to solve at present.

Summary of the invention

The object of this invention is to provide a kind of control method regulating inversion system output voltage, make i-th alternating current source module of power self-balancing pattern can support total voltage and can ensure modular power self-balancing again, improve the efficiency of inversion system; Another object of the present invention is to provide a kind of control system regulating inversion system output voltage.

For solving the problems of the technologies described above, the invention provides a kind of control method regulating inversion system output voltage, being applied to inversion system, wherein, described inversion system comprises N number of alternating current source module, and N is not less than 2, when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, comprising:

Disconnect the DC source in described i-th alternating current source module;

The DC voltage controlling the DCAC module in described i-th alternating current source module is the first predeterminated voltage;

Generate modulating wave, wherein, the sub-voltage making described i-th alternating current source module export when described modulating wave is in the preset range of the peak value of the total voltage that described inversion system exports compensates described total voltage, to make the output voltage of described inversion system meet the second predeterminated voltage, and the power that described modulating wave makes described i-th alternating current source module exchange with described inversion system in one-period is 0;

According to described modulating wave and described first predeterminated voltage, described i-th alternating current source module is controlled, controlling according to presetting N-1 the described alternating current source module of modulating wave to described i-th the alternating current source module of removing simultaneously, achieving the control to described inversion system.

Preferably, the process of described generation modulating wave is specially:

The sub-voltage exported according to N-1 the described alternating current source module removing described i-th alternating current source module in described second predeterminated voltage and N number of described alternating current source module is to generate modulating wave; Wherein, described modulating wave is specially:

Wherein, k is integer, and meet

V _rithe difference of the sub-voltage exported according to described second predeterminated voltage and the individual described alternating current source module of described N-1 sets.

Preferably, the process of described generation modulating wave also comprises:

For superpose a phase angle be used for offsetting the meritorious power consumption of described i-th alternating current source module itself, wherein, for the output valve that described first predeterminated voltage obtains after the first closed-loop control;

Then described modulating wave is specially:

Then be described preset range.

Preferably, the process of described generation modulating wave also comprises:

At v _riwhen () carries out segmentation saltus step t, to v _rit () carries out slope restriction process.

Preferably, the process of described generation modulating wave is specially:

The sub-voltage exported according to N-1 the described alternating current source module removing described i-th alternating current source module in described second predeterminated voltage and N number of described alternating current source module is to generate modulating wave; Wherein, described modulating wave is specially:

v _ri(t)＝-V _risin(3ωt),2kπ≤3ωt≤2(k+1)π；

Wherein, k is integer, V _rithe difference of the sub-voltage exported according to described second predeterminated voltage and the individual described alternating current source module of described N-1 sets.

Preferably, the process of described generation modulating wave also comprises:

Work as v _ritotal modulating wave v of (t) and described inversion system _rwhen the instantaneous voltage symbol between () is identical t, be V _ria proportionality coefficient k is set _ri, be used for offsetting the meritorious power consumption of described i-th alternating current source module itself, wherein, k _rifor the output valve that described first predeterminated voltage obtains after the second closed-loop control;

Then described modulating wave is specially:

$v_{ri}\left(t\right)=\left\{\begin{array}{cc}-V_{ri}sin\left(3\mathrm{\&omega;}t\right),& 2k\mathrm{\&pi;}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{2\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{4\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{5\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2(k+1)\mathrm{\&pi;}\\ -k_{ri}{V}_{ri}sin\left(3\mathrm{\&omega;}t\right),& 2k\mathrm{\&pi;}+\frac{\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{2\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{4\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{5\mathrm{\&pi;}}{3}\end{array}\right.;$

Wherein, k is integer, V _rithe difference of the sub-voltage exported according to described second predeterminated voltage and the individual described alternating current source module of described N-1 sets.

In order to solve the problems of the technologies described above, present invention also offers a kind of control system regulating inversion system output voltage, be applied to inversion system, wherein, described inversion system comprises N number of alternating current source module, and N is not less than 2, when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, comprising:

Switching units, for disconnecting the DC source in described i-th alternating current source module;

Control unit is the first predeterminated voltage for controlling the DC voltage of the DCAC module in described i-th alternating current source module;

Modulating unit, for generating modulating wave, wherein, the sub-voltage making described i-th alternating current source module export when described modulating wave is in the preset range of the peak value of the total voltage that described inversion system exports compensates described total voltage, to make the output voltage of described inversion system meet the second predeterminated voltage, and the power that described modulating wave makes described i-th alternating current source module exchange with described inversion system in one-period is 0;

Described control unit, also for controlling described i-th alternating current source module according to described modulating wave and described first predeterminated voltage, controlling according to presetting N-1 the described alternating current source module of modulating wave to described i-th the alternating current source module of removing simultaneously, achieving the control to described inversion system.

Preferably, this system also comprises:

Slope limiter, at v _riwhen () carries out segmentation saltus step t, to v _rit () carries out slope restriction process.

A kind of control method and system regulating inversion system output voltage disclosed by the invention, when i-th alternating current source module is in power self-balancing pattern, the DC voltage that can control the DCAC module in i-th alternating current source module is the first predeterminated voltage, regeneration modulating wave, according to modulating wave and predeterminated voltage, inversion system is controlled, because the sub-voltage that i-th alternating current source module can be allowed when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports to export compensates total voltage, the second predeterminated voltage is met to make the output voltage of inversion system, and modulating wave i-th alternating current source module is exchanged with inversion system in one-period power be 0, visible, a kind of control method and system regulating inversion system output voltage disclosed by the invention, make i-th alternating current source module of power self-balancing pattern can support total output voltage and can ensure this modular power self-balancing again, improve the efficiency of inversion system.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, be briefly described to the accompanying drawing used required in prior art and embodiment below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the structural representation of a kind of cascade multilevel converter provided by the invention;

Fig. 2 is the structural representation of a kind of alternating current source module provided by the invention;

Fig. 3 is a kind of flow chart regulating the process of the control method of inversion system output voltage provided by the invention;

Fig. 4 is the flow chart that another kind provided by the invention regulates the process of the control method of inversion system output voltage;

Fig. 5 is the principle analysis schematic diagram of the power self-balancing of a kind of i-th alternating current source module provided by the invention;

Fig. 6 is in a kind of inversion system provided by the invention, the modulating wave of N number of alternating current source module and the schematic diagram of total modulating wave;

Fig. 7 is a kind of control principle drawing regulating inversion system output voltage provided by the invention;

Fig. 8 is the principle analysis schematic diagram of the power self-balancing of another kind of i-th alternating current source module provided by the invention;

Fig. 9 is the flow chart that another kind provided by the invention regulates the process of the control method of inversion system output voltage;

Figure 10 is the principle analysis schematic diagram of the power self-balancing of another kind of i-th alternating current source module provided by the invention;

Figure 11 is the control principle drawing that another kind provided by the invention regulates inversion system output voltage;

Figure 12 is the principle analysis schematic diagram of the power self-balancing of another kind of i-th alternating current source module provided by the invention.

Embodiment

Core of the present invention is to provide a kind of control method regulating inversion system output voltage, makes i-th alternating current source module of power self-balancing pattern can support total output voltage and can ensure this modular power self-balancing again, improve the efficiency of inversion system; Another core of the present invention is to provide a kind of control system regulating inversion system output voltage.

For making the object of the embodiment of the present invention, technical scheme and advantage clearly, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.

Embodiment one

Please refer to Fig. 3, Fig. 3 is a kind of flow chart regulating the process of the control method of inversion system output voltage provided by the invention.

The method is applied to inversion system, and wherein, inversion system comprises N number of alternating current source module, and N is not less than 2, and when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, comprising:

Step s101: disconnect the DC source in i-th alternating current source module;

Be understandable that, here DC source can be PV (photovoltaic, photovoltaic) cell panel, battery, super capacitor, fuel cell etc. can send or the unit of stored energy, certainly can also for said units increase corresponding translation circuit after the DC source that formed, the present invention does not do special restriction for the form of current source.

Step s102: the DC voltage controlling the DCAC module in i-th alternating current source module is the first predeterminated voltage;

Be understandable that, DCAC module is here used for direct current to be converted to alternating current, can be 2 level circuits also can be multi-level circuit, and it exchanges end and is connected in series with the end that exchanges of other alternating current source module.

Step s103: generate modulating wave, wherein, the sub-voltage making i-th alternating current source module export when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports compensates total voltage, to make the output voltage of inversion system meet the second predeterminated voltage, and the power that modulating wave makes i-th alternating current source module exchange with inversion system in one-period is 0;

Be understandable that, when i-th alternating current source module cannot active power of output time, the second predeterminated voltage cannot be reached in the peak value place certain limit of the total voltage that inversion system usually can be caused to export, then the second predeterminated voltage can be reached within the scope of remaining other, therefore, as long as the sub-voltage making i-th alternating current source module export when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports compensates total voltage, but to ensure that the power that i-th alternating current source module exchanges with inversion system in one-period is 0 simultaneously, to realize the power-balance of whole inversion system.

It should be noted that the second predeterminated voltage here can be line voltage, can be common civil power effective value 220V, certainly, the present invention do special restriction for the concrete numerical value of the second predeterminated voltage, determines according to actual conditions.

Step s104: control i-th alternating current source module according to modulating wave and the first predeterminated voltage, controlling according to presetting N-1 the alternating current source module of modulating wave to removing i-th alternating current source module simultaneously, achieving the control to inversion system.

Be understandable that controlling according to presetting N-1 the alternating current source module of modulating wave to removing i-th alternating current source module here refers to the remaining alternating current source module of the modulator approach conventionally to removing i-th alternating current source module and control.

It should be noted that, i-th the alternating current source module just set forth in the application in N number of alternating current source module is in processing method during power self-balancing state, if when occurring in inversion system that multiple alternating current source module is in power self-balancing, the processing method of each alternating current source module is consistent with the processing method of the alternating current source module of i-th in the application, does not repeat them here.

A kind of control method and system regulating inversion system output voltage disclosed by the invention, when i-th alternating current source module is in power self-balancing pattern, the DC voltage that can control the DCAC module in i-th alternating current source module is the first predeterminated voltage, regeneration modulating wave, according to modulating wave and predeterminated voltage, inversion system is controlled, because the sub-voltage that i-th alternating current source module can be allowed when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports to export compensates total voltage, the second predeterminated voltage is met to make the output voltage of inversion system, and modulating wave i-th alternating current source module is exchanged with inversion system in one-period power be 0, visible, a kind of control method and system regulating inversion system output voltage disclosed by the invention, make i-th alternating current source module of power self-balancing pattern can support total output voltage and can ensure this modular power self-balancing again, improve the efficiency of inversion system.

Embodiment two

Please refer to Fig. 4, Fig. 4 is the flow chart that another kind provided by the invention regulates the process of the control method of inversion system output voltage;

The method is applied to inversion system, and wherein, inversion system comprises N number of alternating current source module, and N is not less than 2, and when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, comprising:

Step s201: disconnect the DC source in i-th alternating current source module;

Being understandable that, when needing i-th the alternating current source module raises system output voltage being in power self-balancing pattern, the DC source of i-th of an exception alternating current source module can being excised.

Step s202: the DC voltage controlling the DCAC module in i-th alternating current source module is the first predeterminated voltage;

Particularly, the value of the first predeterminated voltage here sets according to the difference of the sub-voltage of N-1 alternating current source module output outside the sub-voltage of the second predeterminated voltage and removing i-th alternating current source module, uses v here _{dc_ref}represent the first predeterminated voltage, usual v _{dc_ref}be greater than above-mentioned difference, but be less than the withstand voltage of each components and parts in DCAC module.

Step s203: the sub-voltage exported according to N-1 alternating current source module of removing i-th alternating current source module in the second predeterminated voltage and N number of alternating current source module generates modulating wave; Wherein, modulating wave is specially:

Wherein, k is integer, and meet

V _rithe difference of the sub-voltage exported with N-1 alternating current source module outside the sub-voltage of removing i-th alternating current source module according to the second predeterminated voltage sets; Wherein, the sub-voltage making i-th alternating current source module export when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports compensates total voltage, to make the output voltage of inversion system meet the second predeterminated voltage, and the power that modulating wave makes i-th alternating current source module exchange with inversion system in one-period is 0;

The object of this step is by the output voltage v of i-th alternating current source module _acibe divided into two parts, within the time period of system output voltage peak value, export the voltage with system output voltage homophase; Section exports the voltage anti-phase with system output voltage At All Other Times, and in one-period, reach positive and negative active balance.During control realization, the modulating wave of i-th alternating current source module (to should the output voltage of module) can be split.

Particularly, please refer to Fig. 5, Fig. 5 is the principle analysis schematic diagram of the power self-balancing of a kind of i-th alternating current source module provided by the invention.

As the modulating wave voltage v of i-th alternating current source module _rit the absolute value of () is less than time alternating current source module absorb active power; When modulating wave absolute value is greater than V _ri0time i-th alternating current source module active power of output; Control action time of each several part well, ensure that this module absorbs within selected cycle and the active power that exports reaches and balances.It is contrary with the i-th module that other module injects a phase place at power self-balancing module work in time bearing merit state, the voltage that amplitude sum is identical with the i-th module.Particularly, please refer to shown in Fig. 6, Fig. 6 is in a kind of inversion system provided by the invention, the modulating wave of N number of alternating current source module and the schematic diagram of total modulating wave.In addition, just list the processing method that an alternating current source module is in self-balancing module in the application, when the quantity of the alternating current source module working in power self-balancing pattern is greater than 1, processing method is identical with time single.

Because the DC capacitor of alternating current source module in CMC often obtains comparatively large, the DC bus ripple produced during module work can not affect the control characteristic of this module.Suppose that the pressure drop on CMC output filter can be ignored relative to output voltage, then cascade multilevel converter brachium pontis output voltage V _abfundamental voltage V _ab1≈ v ₀(t), the total modulating wave v of system _r(t) and v ₀t the phase place of () closely.Here suppose that CMC output voltage and electric current are respectively v ₀(t)=V ₀sin (ω t) and the modulating wave voltage that then can control i-th the alternating current source module working in power self-balancing pattern is:

Derive shi Keling following formula is set up:

By v _ri(t) and i ₀t () is brought formula (1) abbreviation into and can be obtained:

Through mathematical derivation, in formula (1)-(2) be a constant, and with output current i ₀the phase place of (t) irrelevant (haveing nothing to do with system output power factor).

Step s204: for superpose a phase angle be used for the meritorious power consumption of counteracting i-th alternating current source module itself, wherein, it is the output valve that the first predeterminated voltage obtains after the first closed-loop control;

Then modulating wave is specially:

Then be preset range;

Be understandable that, above-mentioned steps s203 carries out calculating when hypothesis i-th alternating current source module does not consume active power, when practical application, i-th alternating current source module can consume active power, therefore, during specific implementation, the control method of other module can be different from i-th the alternating current source module working in power self-balancing pattern, namely control the DC side busbar voltage v of this module _dcimean value be v _{dci_ref}, closed-loop adjustment goes out a phase angle be superimposed upon on for offsetting the active loss of this module itself, please refer to shown in Fig. 7, Fig. 7 is a kind of control principle drawing regulating inversion system output voltage provided by the invention; Here G ₁s () is the compensation tache of the first closed-loop control system, make become large, namely the time of i-th alternating current source module active power of output shortens, and the modulating wave of generation is for controlling the alternating current source module of power self-balancing pattern.

Step s205: at v _riwhen () carries out segmentation saltus step t, to v _rit () carries out slope restriction process;

Be understandable that, to v _riwhen () carries out segment processing t, v _rit the non-linear meeting of () causes modulating wave segmentation smooth not, slight distortion occurs output current, at modulating wave v when therefore realizing _rislope restriction process is increased, to reduce the distortion of inversion system output current in (t) segmentation process.

Particularly, please refer to shown in Fig. 8, Fig. 8 is the principle analysis schematic diagram of the power self-balancing of another kind of i-th alternating current source module provided by the invention.

Step s206: control i-th alternating current source module according to modulating wave and the first predeterminated voltage, controlling according to presetting N-1 the alternating current source module of modulating wave to removing i-th alternating current source module simultaneously, achieving the control to inversion system.

Obtaining modulating wave v _riafter (t), according to modulating wave and the first predeterminated voltage, i-th alternating current source module is controlled.

A kind of control method regulating inversion system output voltage disclosed by the invention, the peak value that can realize the output voltage of inversion system improves V _i, ensure that system obtains higher output voltage.Because i-th the alternating current source module direct voltage working in power self-balancing pattern is controlled, therefore V _ican obtain larger, also namely the method can make the peak value of the output voltage of inversion system improve on 1/ (n-1), still modulation ratio is met when making system be in line voltage peak value, furthermore achieved that i-th alternating current source module of power self-balancing pattern can support total output voltage and can ensure this modular power self-balancing again, improve the efficiency of inversion system.

Embodiment three

Please refer to Fig. 9, Fig. 9 is the flow chart that another kind provided by the invention regulates the process of the control method of inversion system output voltage;

The method is applied to inversion system, and wherein, inversion system comprises N number of alternating current source module, and N is not less than 2, and when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, comprising:

Step s301: disconnect the DC source in i-th alternating current source module;

Step s302: the DC voltage controlling the DCAC module in i-th alternating current source module is the first predeterminated voltage;

Here step s301 is identical with step s202 with the step s201 in embodiment two with step s302, does not repeat them here.

Step s303: the sub-voltage exported according to N-1 alternating current source module of removing i-th alternating current source module in the second predeterminated voltage and N number of alternating current source module generates modulating wave; Wherein, modulating wave is specially:

v _ri(t)＝-V _risin(3ωt),2kπ≤3ωt≤2(k+1)π；

Wherein, k is integer, V _rithe difference of the sub-voltage of foundation the second predeterminated voltage and N-1 alternating current source module output sets; Wherein, the sub-voltage making i-th alternating current source module export when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports compensates total voltage, to make the output voltage of inversion system meet the second predeterminated voltage, and the power that modulating wave makes i-th alternating current source module exchange with inversion system in one-period is 0;

The object of this step is that control i-th alternating current source module injects triple-frequency harmonics to increase total modulation voltage of inversion system to system, ensures that system output voltage peak value place reaches the second predeterminated voltage but is unlikely to ovennodulation.

The present embodiment is identical with the principle of embodiment two, and the concrete waveform unlike modulating wave is different.

Particularly, please refer to shown in Figure 10, Figure 10 is the principle analysis schematic diagram of the power self-balancing of another kind of i-th alternating current source module provided by the invention.

The total modulating wave fundametal compoment supposing all the other alternating current source modules of removing i-th alternating current source module is v _r(t)=V _rsin (ω t), the modulating wave that need adjust i-th alternating current source module is v _ri(t)=-V _risin (3 ω t).Can derive equally and obtain as drawn a conclusion, no matter i.e. CMC output current i ₀t the phase place of () how, the theoretical value of the power output of i-th alternating current source module is always 0, therefore only need ensure v _r(t) and v _ri(t) same-phase.

Step s304: work as v _ritotal modulating wave v of (t) and inversion system _rwhen the instantaneous voltage symbol between () is identical t, be V _ria proportionality coefficient k is set _ri, be used for the meritorious power consumption of counteracting i-th alternating current source module itself, wherein, k _riit is the output valve that the first predeterminated voltage obtains after the second closed-loop control;

Then modulating wave is specially:

$v_{ri}\left(t\right)=\left\{\begin{array}{cc}-V_{ri}sin\left(3\mathrm{\&omega;}t\right),& 2k\mathrm{\&pi;}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{2\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{4\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{5\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2(k+1)\mathrm{\&pi;}\\ -k_{ri}{V}_{ri}sin\left(3\mathrm{\&omega;}t\right),& 2k\mathrm{\&pi;}+\frac{\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{2\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{4\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{5\mathrm{\&pi;}}{3}\end{array}\right.;$

Wherein, k is integer, V _rithe difference of the sub-voltage of foundation the second predeterminated voltage and N-1 alternating current source module output sets;

Consider the meritorious consumption of module itself, for ensureing this alternating current source module busbar voltage stabilization, needing to absorb certain gaining merit, can busbar voltage v be introduced _dciclosed loop adjust a k _ricoefficient, as shown in figure 11, Figure 11 is the control principle drawing that another kind provided by the invention regulates inversion system output voltage; Here G ₂s () is the compensation tache of the second closed-loop control system, as shown in figure 12, Figure 12 is the principle analysis schematic diagram of the power self-balancing of another kind of i-th alternating current source module provided by the invention to the modulating wave of generation; This modulating wave is for controlling i-th the alternating current source module being in power self-balancing pattern.K _rifor reducing v _rv in during (t) >0 _rithe value of (t) >=0 part or increase v during this period _rithe absolute value of (t) <0 part; Or for increasing v _rv in during (t) <=0 _rithe value of (t) >=0 part or reduction v during this period _rithe absolute value of (t) <0 part.Above-mentioned statement also can be described as increasing v _r(t) and v _ri(t) distinct symbols period v _rithe absolute value of (t), or for reducing v _r(t) and v _ri(t) same-sign period v _rithe absolute value of (t).

Step s305: control i-th alternating current source module according to modulating wave and the first predeterminated voltage, controlling according to presetting N-1 the alternating current source module of modulating wave to removing i-th alternating current source module simultaneously, achieving the control to inversion system.

Obtaining modulating wave v _riafter (t), according to modulating wave and the first predeterminated voltage, i-th alternating current source module is controlled.

A kind of control method regulating inversion system output voltage disclosed by the invention, the peak value that can realize the output voltage of inversion system improves V _i, ensure that system obtains higher output voltage.Because i-th the alternating current source module direct voltage working in power self-balancing pattern is controlled, therefore V _ican obtain larger, also namely the method can make the peak value of the output voltage of inversion system improve on 1/ (n-1), still modulation ratio is met when making system be in line voltage peak value, furthermore achieved that i-th alternating current source module of power self-balancing pattern can support total output voltage and can ensure this modular power self-balancing again, improve the efficiency of inversion system.

Corresponding with said method embodiment, present invention also offers a kind of structural representation regulating the control system of inversion system output voltage;

This system is applied to inversion system, and wherein, inversion system comprises N number of alternating current source module, and N is not less than 2, and when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, comprising:

Switching units, for disconnecting the DC source in i-th alternating current source module;

Control unit is the first predeterminated voltage for controlling the DC voltage of the DCAC module in i-th alternating current source module;

Modulating unit, for generating modulating wave, wherein, the sub-voltage making i-th alternating current source module export when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports compensates total voltage, to make the output voltage of inversion system meet the second predeterminated voltage, and the power that modulating wave makes i-th alternating current source module exchange with inversion system in one-period is 0;

Control unit, also for controlling i-th alternating current source module according to modulating wave and the first predeterminated voltage, controlling according to presetting N-1 the alternating current source module of modulating wave to removing i-th alternating current source module simultaneously, achieving the control to inversion system.

As preferably, this system also comprises:

Slope limiter, at v _riwhen () carries out segmentation saltus step t, to v _rit () carries out slope restriction process.

Specific descriptions for this system please refer to said method embodiment, do not repeat them here.

A kind of control system regulating inversion system output voltage disclosed by the invention, when i-th alternating current source module is in power self-balancing pattern, the DC voltage that can control the DCAC module in i-th alternating current source module is the first predeterminated voltage, regeneration modulating wave, according to modulating wave and predeterminated voltage, inversion system is controlled, because the sub-voltage that i-th alternating current source module can be allowed when modulating wave is in the preset range of the peak value of the total voltage that inversion system exports to export compensates total voltage, the second predeterminated voltage is met to make the output voltage of inversion system, and modulating wave i-th alternating current source module is exchanged with inversion system in one-period power be 0, visible, a kind of control system regulating inversion system output voltage disclosed by the invention, make i-th alternating current source module of power self-balancing pattern can support total output voltage and can ensure this modular power self-balancing again, improve the efficiency of inversion system.

The present invention illustrates preferred two kinds of modulating waves, and any other can compensate total voltage in the preset range of the peak value of total voltage, and can realize the modulating wave of this modular power self-balancing, all belongs to the protection category of this patent.

In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar portion mutually see.For device disclosed in embodiment, because it corresponds to the method disclosed in Example, so description is fairly simple, relevant part illustrates see method part.

Also it should be noted that, in this manual, the such as relational terms of first and second grades and so on is only used for an entity or operation to separate with another entity or operating space, and not necessarily requires or imply the relation that there is any this reality between these entities or operation or sequentially.And, term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability, thus make to comprise the process of a series of key element, method, article or equipment and not only comprise those key elements, but also comprise other key elements clearly do not listed, or also comprise by the intrinsic key element of this process, method, article or equipment.When not more restrictions, the key element limited by statement " comprising ... ", and be not precluded within process, method, article or the equipment comprising described key element and also there is other identical element.

Professional can also recognize further, in conjunction with unit and the algorithm steps of each example of embodiment disclosed herein description, can realize with electronic hardware, computer software or the combination of the two, in order to the interchangeability of hardware and software is clearly described, generally describe composition and the step of each example in the above description according to function.These functions perform with hardware or software mode actually, depend on application-specific and the design constraint of technical scheme.Professional and technical personnel can use distinct methods to realize described function to each specifically should being used for, but this realization should not thought and exceeds scope of the present invention.

To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein can without departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (8)

1. regulate a control method for inversion system output voltage, be applied to inversion system, wherein, described inversion system comprises N number of alternating current source module, and N is not less than 2, and when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, is characterized in that, comprising:

Disconnect the DC source in described i-th alternating current source module;

The DC voltage controlling the DCAC module in described i-th alternating current source module is the first predeterminated voltage;

Generate modulating wave, wherein, the sub-voltage making described i-th alternating current source module export when described modulating wave is in the preset range of the peak value of the total voltage that described inversion system exports compensates described total voltage, to make the output voltage of described inversion system meet the second predeterminated voltage, and the power that described modulating wave makes described i-th alternating current source module exchange with described inversion system in one-period is 0;

According to described modulating wave and described first predeterminated voltage, described i-th alternating current source module is controlled, controlling according to presetting N-1 the described alternating current source module of modulating wave to described i-th the alternating current source module of removing simultaneously, achieving the control to described inversion system.

2. control method as claimed in claim 1, it is characterized in that, the process of described generation modulating wave is specially:

The sub-voltage exported according to N-1 the described alternating current source module removing described i-th alternating current source module in described second predeterminated voltage and N number of described alternating current source module is to generate modulating wave; Wherein, described modulating wave is specially:

Wherein, k is integer, and meet

V _rithe difference of the sub-voltage exported according to described second predeterminated voltage and the individual described alternating current source module of described N-1 sets.

3. control method as claimed in claim 2, it is characterized in that, the process of described generation modulating wave also comprises:

For superpose a phase angle be used for offsetting the meritorious power consumption of described i-th alternating current source module itself, wherein, for the output valve that described first predeterminated voltage obtains after the first closed-loop control;

Then described modulating wave is specially:

Then be described preset range.

4. control method as claimed in claim 3, it is characterized in that, the process of described generation modulating wave also comprises:

At v _riwhen () carries out segmentation saltus step t, to v _rit () carries out slope restriction process.

5. control method as claimed in claim 1, it is characterized in that, the process of described generation modulating wave is specially:

The sub-voltage exported according to N-1 the described alternating current source module removing described i-th alternating current source module in described second predeterminated voltage and N number of described alternating current source module is to generate modulating wave; Wherein, described modulating wave is specially:

v _ri(t)＝-V _risin(3ωt),2kπ≤3ωt≤2(k+1)π；

Wherein, k is integer, V _rithe difference of the sub-voltage exported according to described second predeterminated voltage and the individual described alternating current source module of described N-1 sets.

6. control method as claimed in claim 5, it is characterized in that, the process of described generation modulating wave also comprises:

Work as v _ritotal modulating wave v of (t) and described inversion system _rwhen the instantaneous voltage symbol between () is identical t, be V _ria proportionality coefficient k is set _ri, be used for offsetting the meritorious power consumption of described i-th alternating current source module itself, wherein, k _rifor the output valve that described first predeterminated voltage obtains after the second closed-loop control;

Then described modulating wave is specially:

$v_{ri}\left(t\right)=\left\{\begin{array}{c}-V_{ri}sin\left(3\mathrm{\&omega;}t\right),2k\mathrm{\&pi;}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{2\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{4\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{5\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2(k+1)\mathrm{\&pi;}\\ -k_{ri}{V}_{ri}\sin \left(3\mathrm{\&omega;}t\right),2k\mathrm{\&pi;}+\frac{\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{2\mathrm{\&pi;}}{3};2k\mathrm{\&pi;}+\frac{4\mathrm{\&pi;}}{3}\&le;3\mathrm{\&omega;}t<2k\mathrm{\&pi;}+\frac{5\mathrm{\&pi;}}{3}\end{array}\right.;$

Wherein, k is integer, V _rithe difference of the sub-voltage exported according to described second predeterminated voltage and the individual described alternating current source module of described N-1 sets.

7. regulate a control system for inversion system output voltage, be applied to inversion system, wherein, described inversion system comprises N number of alternating current source module, and N is not less than 2, and when i-th alternating current source module is in power self-balancing pattern, 1≤i≤N, is characterized in that, comprising:

Switching units, for disconnecting the DC source in described i-th alternating current source module;

Control unit is the first predeterminated voltage for controlling the DC voltage of the DCAC module in described i-th alternating current source module;

Modulating unit, for generating modulating wave, wherein, the sub-voltage making described i-th alternating current source module export when described modulating wave is in the preset range of the peak value of the total voltage that described inversion system exports compensates described total voltage, to make the output voltage of described inversion system meet the second predeterminated voltage, and the power that described modulating wave makes described i-th alternating current source module exchange with described inversion system in one-period is 0;

Described control unit, also for controlling described i-th alternating current source module according to described modulating wave and described first predeterminated voltage, controlling according to presetting N-1 the described alternating current source module of modulating wave to described i-th the alternating current source module of removing simultaneously, achieving the control to described inversion system.

8. control system as claimed in claim 7, and be characterised in that, this system also comprises:

Slope limiter, at v _riwhen () carries out segmentation saltus step t, to v _rit () carries out slope restriction process.