CN106208643A - Based on the common mode current suppressing method under the non-equal illumination of photovoltaic combining inverter - Google Patents

Based on the common mode current suppressing method under the non-equal illumination of photovoltaic combining inverter Download PDF

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CN106208643A
CN106208643A CN201610628337.6A CN201610628337A CN106208643A CN 106208643 A CN106208643 A CN 106208643A CN 201610628337 A CN201610628337 A CN 201610628337A CN 106208643 A CN106208643 A CN 106208643A
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voltage
power systems
magnitude
combining inverter
photovoltaic
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胡辉勇
唐子程
宣荣喜
滕飞
王斌
宋建军
舒斌
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Xidian University
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Xidian University
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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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • 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
    • H02J3/383—
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H02M1/123—Suppression of common mode voltage or current
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Abstract

The present invention discloses a kind of based on the common mode current suppressing method under the non-equal illumination of photovoltaic combining inverter, including: form different magnitude of voltage after accepting illumination according to two described photovoltaic battery panels, form multiple different output voltage values according to the different Switch State Combination in Power Systems of described H bridge module, set up one-dimensional space vector controlled region according to described different output voltage values；And calculate the parasitic capacitor voltage value between described photovoltaic battery panel and ground；Two output voltage values closest to described pre-output magnitude of voltage are determined in one-dimensional space vector controlled region；Select described parasitic capacitor voltage value equal from the different Switch State Combination in Power Systems that said two output voltage values is corresponding or immediate two Switch State Combination in Power Systems, and control conducting and the closedown of two described H bridge module breaker in middle pipes, the method uses the neighbouring vectors synthesized reference vector making parasitic capacitor voltage keep relative constancy, the inhibition of the common mode current being effectively increased under the non-equal illumination of photovoltaic combining inverter.

Description

Based on the common mode current suppressing method under the non-equal illumination of photovoltaic combining inverter
Technical field
The invention belongs to active inverter technical field, particularly relate to a kind of based under the non-equal illumination of photovoltaic combining inverter Common mode current suppressing method.
Background technology
Photovoltaic parallel in system refers to that the unidirectional current produced by photovoltaic array is converted to and electricity through combining inverter The same amplitude of net voltage, same to frequency, the alternating current of homophase, and realize the system being connected with electrical network.For ensureing to use safety, VDE4105 Standard has strict restriction to photovoltaic parallel in system common mode current.Frequently with band power frequency or high frequency transformer in photovoltaic parallel in system Isolated form photovoltaic combining inverter, which ensure that the electrical isolation between electrical network and photovoltaic system, thus provides personnel protection And avoid the common mode current between photovoltaic system and ground.But, according to Industrial Frequency Transformer, its volume is big, Heavy Weight and valency Lattice are expensive；According to high frequency transformer, power conversion circuit will be divided into several levels so that control from being complicated, also reduce simultaneously The efficiency of system.Therefore, efficiency height, volume non-isolated grid-connected inverter little, lightweight low cost have a clear superiority in. But the elimination of transformator makes there has been electrical connection between photovoltaic system and electrical network, and common mode current may be significantly increased, and brings Conduction and radiation interference, increase grid current harmonic and loss, even jeopardize equipment and personal security.Therefore low common mode current Non-isolated photovoltaic DC-to-AC converter becomes one of study hotspot.
General common mode current suppressing method can be summarized as following 3 kinds, is respectively as follows: 1) use modified model topology, such as H5 Topology, H6 topology etc.；2) passive filter is used, such as common mode inductance and electromagnetic interface filter etc.；3) new modulator approach is used.
Research to common mode current suppressing method at present, the research of the single-phase topology of uniform illumination is the most, non-homogeneous Topology research under light conditions is less.Prior art can not effectively suppress non-isolation type Cascade-type photovoltaic grid-connected inverter non-all The generation of common mode current under illumination.
Summary of the invention
In view of this, the technical problem to be solved is for non-isolation type cascade connection type photovoltaic in prior art also Can not effectively suppress the deficiency of common mode current under the non-equal illumination of net inverter, it is provided that a kind of based on photovoltaic combining inverter non-all Common mode current suppressing method under illumination.
The embodiment provides common mode current suppression side under a kind of non-equal illumination based on photovoltaic combining inverter Method, is applied to non-isolation type tandem photovoltaic combining inverter, and described non-isolation type tandem photovoltaic combining inverter includes two-stage light Volt cell panel and two H bridge modules of correspondence, described H bridge module includes four switching tubes being arranged on two brachium pontis, wherein, Described suppressing method includes:
Different magnitude of voltage is formed, according to two described H bridge modules after accepting illumination according to two described photovoltaic battery panels Different Switch State Combination in Power Systems form multiple different output voltage values, set up the one-dimensional space according to described different output voltage values Vector controlled region；
When described different Switch State Combination in Power Systems form multiple different output voltage values, calculate described photovoltaic battery panel with Parasitic capacitor voltage value between ground；
Determine closest to described pre-output in the position in described one-dimensional space vector controlled region according to pre-output magnitude of voltage Two output voltage values of magnitude of voltage；
Select and described parasitic capacitor voltage value from the different Switch State Combination in Power Systems that said two output voltage values is corresponding Equal or immediate two Switch State Combination in Power Systems, and control two described H bridge moulds according to said two Switch State Combination in Power Systems The conducting of block breaker in middle pipe and closedown.
In one embodiment of the invention, if the ultimate unit of input voltage is E, it is assumed that two-stage photovoltaic battery panel is because connecing By different illumination conditions produce 3:1 ratio input voltage, then cascade after can be formed multiple different output voltage values for-4E ,- 3E ,-2E ,-E, 0, E, 2E, 3E and 4E.
In one embodiment of the invention, one-dimensional space vector controlled district is set up according to described different output voltage values Territory, including:
Represent each described H bridge module output-Vi by numeral 0,1,2 respectively, 0, Vi tri-kind of magnitude of voltage, then with numeral 00, 01,02,10,11,12,20,21 and 22 represent respectively described non-isolation type tandem photovoltaic combining inverter output magnitude of voltage- 4E ,-3E ,-2E ,-E, 0, E, 2E, 3E and 4E, by described non-isolation type tandem photovoltaic combining inverter output magnitude of voltage-4E ,- The corresponding relation of 3E ,-2E ,-E, 0, E, 2E, 3E and 4E and numeral 00,01,02,10,11,12,20,21 and 22 forms described one Dimension space vector controlled region.
In one embodiment of the invention, formed multiple according to the different Switch State Combination in Power Systems of two described H bridge modules Different output voltage values, including:
Represent each switch-off of H bridge module and opening state by numeral 0,1 respectively, then produce 0101,0100, 0111,0110,0001,1101,0000,1111,0011,1100,0010,1110,1001,1 000,1011,1010 16 kinds of shapes State, respectively magnitude of voltage-the 4E of corresponding non-isolation type tandem photovoltaic combining inverter output ,-3E ,-2E ,-E, 0, E, 2E, 3E and 4E。
In one embodiment of the invention, described non-isolation type tandem photovoltaic combining inverter includes control Inductance (L1) and second also network interface inductance (L2), it is assumed that described control inductance (L1) and described second network interface The inductance value of inductance (L2) is equal, then, when described different Switch State Combination in Power Systems form multiple different output voltage values, calculate Parasitic capacitor voltage value between described photovoltaic battery panel and ground, including:
Wherein, Vcpv1It is the parasitic capacitor voltage value between the first photovoltaic panel and ground, Vcm1It is The common-mode voltage of one H bridge module, Vdm1It it is the differential mode voltage of a H bridge module；
Wherein, Vcpv2It is the parasitic capacitor voltage value between the second photovoltaic panel and ground, Vcm2It is The common-mode voltage of two H bridge modules, Vdm2It it is the differential mode voltage of the 2nd H bridge module.
In one embodiment of the invention, control in two described H bridge modules according to said two Switch State Combination in Power Systems The conducting of switching tube and closedown, including:
According to described pre-output voltage position in described one-dimensional space vector controlled region, determine that said two switchs The on off state dutycycle that combinations of states is corresponding；
Two on off states corresponding to said two Switch State Combination in Power Systems and described on off state dutycycle are carried out linearly Synthesis is to control conducting and the closedown of the switching tube of two described H bridge modules.
In one embodiment of the invention, the computing formula of described dutycycle is:
Wherein, VrefFor pre-output magnitude of voltage, E is the ultimate unit of input voltage, t1、t2It is two Planting the dutycycle of on off state, floor is downward rounding operation function.
Compared with prior art, the present invention obtains and provides the benefit that:
(1) use the method control vector obtained and the switch combination chosen grid-connected inverse to non-isolation type tandem photovoltaic The switching tube becoming device is controlled, and makes parasitic capacitor voltage keep relative constancy and then improve the inhibition of common mode current.
(2) select neighbouring vectors according to reference to phase voltage and obtain the side of each vector coefficient in synthesized reference vector Method, directly can be obtained precise results by computer programming and be easy to be controlled common mode current further, improve inverter efficiency, Improve the simplicity of actual application, reduce difficulty in computation and cost.
Accompanying drawing explanation
In order to understand the explanation embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing skill In art description, the required accompanying drawing used is briefly described.Accompanying drawing in describing below is some embodiments of the present invention, right In those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to obtain other according to these accompanying drawings Accompanying drawing.
Fig. 1 is common mode current suppression under a kind of based on photovoltaic combining inverter the non-equal illumination that the embodiment of the present invention provides Method schematic flow sheet；
Fig. 2 is the circuit diagram of a kind of non-isolation type Cascade-type photovoltaic grid-connected inverter that the embodiment of the present invention provides；
Fig. 3 is a kind of Commonmode model schematic diagram that the embodiment of the present invention provides；
Fig. 4 is a kind of simplification Commonmode model schematic diagram that the embodiment of the present invention provides；
Fig. 5 is a kind of one-dimensional space vector controlled area schematic that the embodiment of the present invention provides；
Fig. 6 is a kind of inverter state calculation flow chart that the embodiment of the present invention provides.
Detailed description of the invention
For making those skilled in the art be more fully understood that technical scheme, below in conjunction with the accompanying drawings and specific embodiment party Under case equal illumination non-to non-isolation type Cascade-type photovoltaic grid-connected inverter of the present invention, the space vector suppressing method of common mode current is made Describe in further detail.Example only represents possible change.Unless explicitly requested, otherwise individually components and functionality is optional , and the order operated can change.The part of some embodiments and feature can be included in or replace other and implement The forehead of scheme divides and feature.The scope of embodiment of the present invention includes the gamut of claims, and right is wanted Seek all obtainable equivalent of book.
Below in conjunction with the accompanying drawings the present invention is described in further details.
Embodiment one
Referring to Fig. 1, Fig. 1 is a kind of based on photovoltaic combining inverter the common mode current suppression that the embodiment of the present invention provides Method schematic flow sheet, the method is applied to non-isolation type tandem photovoltaic combining inverter, described non-isolation type cascade light Volt combining inverter includes two H bridge modules of two-stage photovoltaic battery panel and correspondence, and described H bridge module includes being arranged at two bridges Four switching tubes on arm, wherein, described suppressing method includes:
Different magnitude of voltage is formed, according to two described H bridge modules after accepting illumination according to two described photovoltaic battery panels Different Switch State Combination in Power Systems form multiple different output voltage values, set up the one-dimensional space according to described different output voltage values Vector controlled region；
When described different Switch State Combination in Power Systems form multiple different output voltage values, calculate described photovoltaic battery panel with Parasitic capacitor voltage value between ground；
Determine closest to described pre-output in the position in described one-dimensional space vector controlled region according to pre-output magnitude of voltage Two output voltage values of magnitude of voltage；
Select and described parasitic capacitor voltage value from the different Switch State Combination in Power Systems that said two output voltage values is corresponding Equal or immediate two Switch State Combination in Power Systems, and control two described H bridge moulds according to said two Switch State Combination in Power Systems The conducting of block breaker in middle pipe and closedown.
Wherein, if the ultimate unit of input voltage is E, it is assumed that two-stage photovoltaic battery panel produces because accepting different illumination conditions The input voltage of 3:1 ratio, then cascade after can be formed multiple different output voltage values for-4E ,-3E ,-2E ,-E, 0, E, 2E, 3E and 4E.
One-dimensional space vector controlled region is set up according to described different output voltage values, including:
Represent each described H bridge module output-Vi by numeral 0,1,2 respectively, 0, Vi tri-kind of magnitude of voltage, then with numeral 00, 01,02,10,11,12,20,21 and 22 represent respectively described non-isolation type tandem photovoltaic combining inverter output magnitude of voltage- 4E ,-3E ,-2E ,-E, 0, E, 2E, 3E and 4E, by described non-isolation type tandem photovoltaic combining inverter output magnitude of voltage-4E ,- The corresponding relation of 3E ,-2E ,-E, 0, E, 2E, 3E and 4E and numeral 00,01,02,10,11,12,20,21 and 22 forms described one Dimension space vector controlled region.
Wherein, form multiple different output voltage values according to the different Switch State Combination in Power Systems of two described H bridge modules, bag Include:
Represent each switch-off of H bridge module and opening state by numeral 0,1 respectively, then produce 0101,0100, 0111,0110,0001,1101,0000,1111,0011,1100,0010,1110,1001,1 000,1011,1010 16 kinds of shapes State, respectively magnitude of voltage-the 4E of corresponding non-isolation type tandem photovoltaic combining inverter output ,-3E ,-2E ,-E, 0, E, 2E, 3E and 4E。
Wherein, described non-isolation type tandem photovoltaic combining inverter includes control inductance (L1) and second grid-connected Interface inductance (L2), it is assumed that described control inductance (L1) and described second the inductance value phase of network interface inductance (L2) Deng, then when described different Switch State Combination in Power Systems form multiple different output voltage values, calculate described photovoltaic battery panel and ground Between parasitic capacitor voltage value, including:
Wherein, Vcpv1It is the parasitic capacitor voltage value between the first photovoltaic panel and ground, Vcm1It is The common-mode voltage of one H bridge module, Vdm1It it is the differential mode voltage of a H bridge module；
Wherein, Vcpv2Being the parasitic capacitor voltage value between the second photovoltaic panel and ground, Vcm2 is The common-mode voltage of the 2nd H bridge module, Vdm2It it is the differential mode voltage of the 2nd H bridge module.
Wherein, control conducting and the closedown of two described H bridge module breaker in middle pipes according to said two Switch State Combination in Power Systems, Including:
According to described pre-output voltage position in described one-dimensional space vector controlled region, determine that said two switchs The on off state dutycycle that combinations of states is corresponding；
Two on off states corresponding to said two Switch State Combination in Power Systems and described on off state dutycycle are carried out linearly Synthesis is to control conducting and the closedown of the switching tube of two described H bridge modules.
Furthermore, the computing formula of described dutycycle is:
Wherein, VrefFor pre-output magnitude of voltage, E is the ultimate unit of input voltage, t1、t2It is two Planting the dutycycle of on off state, floor is downward rounding operation function.
The present embodiment, controls vector and the switch combination chosen to non-isolation type tandem photovoltaic by what above method obtained The switching tube of combining inverter is controlled, and makes parasitic capacitor voltage keep relative constancy and then improve the suppression effect of common mode current Really, solve and can not effectively suppress common mode current under the non-equal illumination of non-isolation type Cascade-type photovoltaic grid-connected inverter in prior art Problem, reached preferably suppression the non-equal illumination of non-isolation type Cascade-type photovoltaic grid-connected inverter under common mode current occur effect Really.
Embodiment two
Fig. 1 be the embodiment of the present invention provide a kind of common mode current suppressing method in photovoltaic combining inverter flow process Schematic diagram；Comprise the following steps:
Step a, forms different magnitude of voltage, according to two described H bridges after accepting illumination according to two described photovoltaic battery panels The different Switch State Combination in Power Systems of module form multiple different output voltage values, set up one according to described different output voltage values Dimension space vector controlled region；
Step b, when described different Switch State Combination in Power Systems form multiple different output voltage values, calculates described photovoltaic electric Parasitic capacitor voltage value between pond plate and ground；
Step c, determines closest to described in the position in described one-dimensional space vector controlled region according to pre-output magnitude of voltage Two output voltage values of pre-output magnitude of voltage；
Step d, selects and described parasitic capacitance from the different Switch State Combination in Power Systems that said two output voltage values is corresponding Magnitude of voltage is equal or immediate two Switch State Combination in Power Systems, and described in controlling two according to said two Switch State Combination in Power Systems The conducting of H bridge module breaker in middle pipe and closedown.
Fig. 2 show the schematic diagram of typical case's non-isolation type tandem photovoltaic combining inverter, wherein: E, L1, L2 are respectively electricity Net voltage and and network interface inductance；Cpv1 and Cpv2 is the parasitic capacitance between photovoltaic Pv and the earth, its value and external environment condition bar The factors such as part, photovoltaic battery panel dimensional structure are relevant, typically at about 50～150 nF/kW；C is posting between outfan and the earth Raw electric capacity, Zg is the common code impedance that other non-ideal factors cause.
Fig. 3 is the Commonmode model of system shown in Figure 2, ignores the differential mode electricity that line voltage affects and defines i-th inverter Pressure is Vdmi=Vai-Vbi, and common-mode voltage is Vcmi=(Vai+Vbi)/2, and available system as shown in Figure 4 simplifies common mode mould Type.
Assume and network interface inductance L1=L2=L, Kirchhoff's law can obtain
Vcpv1-Vcm1-0.5Vdm1+VL=0
Vcpv2-Vcm2-0.5Vdm2-VL=0
Vcpv1-Vcm1-0.5Vdm1+0.5Vdm2+Vcm2-Vcpv2=0
Can be obtained by above three formulas:
V c p v 1 = V c m 1 + V d m 1 2
V c p v 2 = V c m 2 - V d m 2 2
System common-mode electric current
Therefore, for the common mode current of suppression system, as long as ensureing parasitic capacitor voltage Vcpv1+Vcpv2Converted at switch Journey is held essentially constant value.
Use 0,1, the 2-Vi representing every grade of inverter output, 0, Vi tri-kind of state.Two-stage photovoltaic battery panel of the present invention because of Accept different illumination conditions and produce the input voltage of 3:1 ratio, i.e. will be produced-4E～4E totally nine voltage by nine kinds of states.
Use 0,1 to represent each switch-off and opening state will produce 16 kinds of different switch combinations.
Above inverter state, switch combination, output voltage are collected and obtains common mode, differential mode voltage and parasitic capacitor voltage As shown in table 1.
Table 1
With input voltage, pre-output voltage is normalized, obtains normalization coefficient
If input voltage ultimate unit is E, pre-output voltage is vref, a is normalization coefficient, then utilize following formula to obtain Arrive
a = V r e f E
Here pre-output voltage v is takenrefFor 50Hz, amplitude is the sine wave of 0.5E, then a=0.5.
According to the one-dimensional space vector controlled region shown in Fig. 5 choose inverter state be 11 be 12 neighbouring vectors with close Become reference vector.
With normalization coefficient a further design factor ai=floor (a), the floor (x) in formula are downward bracket function, aiFor minus infinity direction near the integer of a.Then ai=0.
It is combined as 0,010 0000 according to the optional pass that takes away of the on off state that table 1 on off state is corresponding
According to coefficient a and a obtainedi, utilize following two formula to calculate each inverter state persistent period t1 And t2
t1=a-ai
t2=1-t1
The calculating of other situations can refer to calculation flow chart as shown in Figure 6 and carries out, upper1-lower1 and upper2- Lower2 represents the state of every grade of inverter output respectively.
Use the method control vector obtained and the switch combination chosen to non-isolation type many level tandem photovoltaic also The switching tube of net inverter is controlled, and makes parasitic capacitor voltage keep relative constancy and then improve the suppression effect of common mode current Really.
It should also be appreciated by one skilled in the art that the described above to disclosed example, just to the explanation present invention Principle so that professional and technical personnel in the field's exemplary embodiment of being capable of or use the present invention and using, but this Invention is not limited thereto.For the ordinary skill in the art, in the feelings without departing from spirit and substance of the present invention Under condition, can make various modification and improvement, these modification and improvement are also considered as protection scope of the present invention.

Claims (7)

1., based on the common mode current suppressing method under the non-equal illumination of photovoltaic combining inverter, it is applied to non-isolation type cascade light Volt combining inverter, described non-isolation type tandem photovoltaic combining inverter includes two H bridges of two-stage photovoltaic battery panel and correspondence Module, described H bridge module includes four switching tubes being arranged on two brachium pontis, it is characterised in that described suppressing method includes:
Different magnitude of voltage is formed, according to the difference of two described H bridge modules after accepting illumination according to two described photovoltaic battery panels Switch State Combination in Power Systems forms multiple different output voltage values；One-dimensional space vector is set up according to described different output voltage values Control area；
When described different Switch State Combination in Power Systems form multiple different output voltage values, calculate described photovoltaic battery panel and ground Between parasitic capacitor voltage value；
Determine closest to described pre-output voltage in the position in described one-dimensional space vector controlled region according to pre-output magnitude of voltage Two output voltage values of value；
Select equal with described parasitic capacitor voltage value from the different Switch State Combination in Power Systems that said two output voltage values is corresponding Or immediate two Switch State Combination in Power Systems, and control in two described H bridge modules according to said two Switch State Combination in Power Systems The conducting of switching tube and closedown.
Suppressing method the most according to claim 1, it is characterised in that if the ultimate unit of input voltage is E, it is assumed that two-stage Photovoltaic battery panel produces the input voltage of 3:1 ratio because accepting different illumination conditions, then form multiple different output after cascade Magnitude of voltage is-4E ,-3E ,-2E ,-E, 0, E, 2E, 3E and 4E.
Suppressing method the most according to claim 2, it is characterised in that set up one-dimensional according to described different output voltage values Frequency conversion control region, including:
Represent each described H bridge module output-Vi by numeral 0,1,2 respectively, 0, Vi tri-kind of magnitude of voltage, then with numeral 00,01, 02,10,11,12,20,21 and 22 represent respectively described non-isolation type tandem photovoltaic combining inverter output magnitude of voltage-4E ,- 3E ,-2E ,-E, 0, E, 2E, 3E and 4E, by described non-isolation type tandem photovoltaic combining inverter output magnitude of voltage-4E ,-3E ,- The corresponding relation of 2E ,-E, 0, E, 2E, 3E and 4E and numeral 00,01,02,10,11,12,20,21 and 22 forms described one-dimensional sky Between vector controlled region.
Suppressing method the most according to claim 1, it is characterised in that according to the different switch shapes of two described H bridge modules State combination forms multiple different output voltage values, including:
Represent each switch-off of H bridge module and opening state by numeral 0,1 respectively, then produce 0101,0100,0111, 0110,0001,1101,0000,1111,0011,1100,0010,1110,1001,1000,1011,1,010 ten six kind of state, point Magnitude of voltage-the 4E of corresponding non-isolation type tandem photovoltaic combining inverter output ,-3E ,-2E ,-E, 0, E, 2E, 3E and 4E.
Suppressing method the most according to claim 1, it is characterised in that described non-isolation type tandem photovoltaic combining inverter bag Include control inductance (L1) and second also network interface inductance (L2), it is assumed that described control inductance (L1) and institute State second and the inductance value of network interface inductance (L2) equal, then form multiple different output at described different Switch State Combination in Power Systems During magnitude of voltage, calculate the parasitic capacitor voltage value between described photovoltaic battery panel and ground, including:
Wherein, Vcpv1It is the parasitic capacitor voltage value between the first photovoltaic panel and ground, Vcm1It it is a H bridge The common-mode voltage of module, Vdm1It it is the differential mode voltage of a H bridge module；
Wherein, Vcpv2It is the parasitic capacitor voltage value between the second photovoltaic panel and ground, Vcm2It it is the 2nd H bridge The common-mode voltage of module, Vdm2It it is the differential mode voltage of the 2nd H bridge module.
Suppressing method the most according to claim 1, it is characterised in that control two according to said two Switch State Combination in Power Systems The conducting of described H bridge module breaker in middle pipe and closedown, including:
According to described pre-output voltage position in described one-dimensional space vector controlled region, determine said two on off state The on off state dutycycle that combination is corresponding；
Two on off states corresponding to said two Switch State Combination in Power Systems and described on off state dutycycle linearly synthesize To control conducting and the closedown of the switching tube of two described H bridge modules.
Suppressing method the most according to claim 6, it is characterised in that the computing formula of described dutycycle is:
Wherein, VrefFor pre-output magnitude of voltage, E is the ultimate unit of input voltage, t1、t2It is two kinds to open The dutycycle of off status, floor is downward rounding operation function.
CN201610628337.6A 2016-08-03 2016-08-03 Based on the common mode current suppressing method under the non-equal illumination of photovoltaic combining inverter Pending CN106208643A (en)

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CN110445442A (en) * 2019-07-02 2019-11-12 华夏天信智能物联股份有限公司 A kind of three-phase cascade connection type three-level inverter control method
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Application publication date: 20161207