阅读说明：本技术 一种高功率密度非隔离型光伏并网逆变器 (A kind of high power density non-isolated photovoltaic grid-connected inverter ) 是由 王清媛 丁永强 吴良材 熊伟 任齐星 程浩 于 2019-09-30 设计创作，主要内容包括：本发明实施例公开了一种高功率密度非隔离型光伏并网逆变器,包括第一光伏阵列、第二光伏阵列、第一三相逆变器、第二三相逆变器、第一滤波器、第二滤波器、第一单相三绕组自耦变压器、第二单相三绕组自耦变压器、第三单相三绕组自耦变压器。本发明采用三个单相三绕组自耦变压器作为并网变压器,使得并网变压器的容量与使用传统工频变压器相比减小82%,光伏并网逆变器的功率密度大幅提高、绕组匝数减少、节约成本；三个单相三绕组自耦变压器绕组结构采用移相多重联结方式,当两组光伏阵列并联运行时,采用SPWM控制两组三相逆变器,使得滤波器输出端的同一相两个原边绕组间电压存在30°相位差,能抑制特征次谐波并网电流,提高电能质量。(The embodiment of the invention discloses a kind of high power density non-isolated photovoltaic grid-connected inverters, including the first photovoltaic array, the second photovoltaic array, the first three-phase inverter, the second three-phase inverter, first filter, second filter, the first single-phase three-winding autotransformer, the second single-phase three-winding autotransformer, third single-phase three-winding autotransformer.The present invention is using three single-phase three-winding autotransformers as grid-connected transformer, so that the capacity of grid-connected transformer reduces 82% compared with using traditional Industrial Frequency Transformer, the power density of photovoltaic combining inverter is greatly improved, umber of turn is reduced, save the cost；Three single-phase three-winding autotransformer winding constructions use phase shift multiple connection mode, when two groups of photovoltaic array parallel runnings, two groups of three-phase inverters are controlled using SPWM, so that there are 30 ° of phase differences for voltage between two primary side windings of the same phase of filter output, energy inhibitory character subharmonic grid-connected current, improves power quality.)

1. a kind of high power density non-isolated photovoltaic grid-connected inverter, which is characterized in that including the first photovoltaic array, the second light Photovoltaic array, the first three-phase inverter, the second three-phase inverter, first filter, second filter and grid-connected transformer, the first light Photovoltaic array, the first three-phase inverter, first filter are sequentially connected, the second photovoltaic array, the second three-phase inverter, the second filtering Device is sequentially connected, and grid-connected transformer is connect with the output end of first filter and second filter, and grid-connected transformer is single by first Phase three-winding autotransformer, the second single-phase three-winding autotransformer, third single-phase three-winding autotransformer composition, it is grid-connected Three single-phase three-winding autotransformer winding constructions of transformer use phase shift multiple connection mode.

2. high power density non-isolated photovoltaic grid-connected inverter as described in claim 1, which is characterized in that first light The structure of photovoltaic array and the second photovoltaic array, specification are identical, structure, the specification of the first three-phase inverter and the second three-phase inverter Identical, first filter is identical with structure, the specification of second filter；The output end of first photovoltaic array and the second photovoltaic array Anode is connect with the input anode of the first three-phase inverter and the second three-phase inverter respectively, the first photovoltaic array and the second light The negative pole of output end of photovoltaic array is connect with the input cathode of the first three-phase inverter and the second three-phase inverter respectively, and the one or three The three-phase output end of phase inverter and the second three-phase inverter three-phase input end with first filter and second filter respectively Connection；The input terminal of the a1 winding of a phase output terminal and the second single-phase three-winding autotransformer of first filter is connected, and first The input terminal of the b1 winding of the b phase output terminal and third single-phase three-winding autotransformer of filter is connected, the c of first filter Phase output terminal is connected with the input terminal of the c1 winding of the first single-phase three-winding autotransformer；The a phase output terminal of second filter It is connected with the input terminal of the a2 winding of the second single-phase three-winding autotransformer, the b phase output terminal and third list of second filter The input terminal of the b2 winding of phase three-winding autotransformer is connected, the c phase output terminal of second filter and the first single-phase three winding The input terminal of the c2 winding of auto-transformer is connected.

3. high power density non-isolated photovoltaic grid-connected inverter as described in claim 1, which is characterized in that first single-phase three Winding autotransformer, the second single-phase three-winding autotransformer, the structure of third single-phase three-winding autotransformer are identical, Be made of two stems of the first stem and the second stem, the first stem, the first stem be the first primary side winding and the second primary side around Group, the second stem are public winding, and it is respectively N1 and N2, public winding that the first primary side winding and the second primary side winding, which correspond to the number of turns, Corresponding the number of turns is N3, and the turn ratio between three windings is N1:N2:N3=0.1547:0.1547:1.

4. high power density non-isolated photovoltaic grid-connected inverter as claimed in claim 3, which is characterized in that first single-phase three The output end of two primary side winding of winding autotransformer is connected, the output of two primary side winding of the second single-phase three-winding autotransformer End is connected, and the output end of two primary side winding of third single-phase three-winding autotransformer is connected, first, second, third single-phase three around The secondary side of group auto-transformer is all made of triangle junction, the first end of the first single-phase three-winding autotransformer vice-side winding with The output end and power grid a phase of second single-phase three-winding autotransformer, two primary side winding are connected, and the first single-phase three winding self coupling becomes The second end of depressor vice-side winding is connected with the first end of the second single-phase three-winding autotransformer vice-side winding；Second single-phase three The first end of winding autotransformer vice-side winding and the output end of two primary side winding of third single-phase three-winding autotransformer and Power grid b phase is connected, the second end and the single-phase three winding self coupling transformation of third of the second single-phase three-winding autotransformer vice-side winding The first end of device vice-side winding is connected；The first end of third single-phase three-winding autotransformer vice-side winding with first single-phase three around The output end and power grid c phase of group two primary side winding of auto-transformer are connected, third single-phase three-winding autotransformer vice-side winding Second end be connected with the first end of the first single-phase three-winding autotransformer vice-side winding.

5. high power density non-isolated photovoltaic grid-connected inverter as claimed in claim 3, which is characterized in that the one or three contrary There are 30 ° of phase differences for the phase voltage of the in-phase output end of change device and the second three-phase inverter.

6. high power density non-isolated photovoltaic grid-connected inverter as claimed in claim 2, which is characterized in that the first photovoltaic battle array Column are made of with the second photovoltaic array the identical photovoltaic cell plate serioparallel of multiple specifications；First three-phase inverter and the two or three Phasing commutator includes that the three-phase four-arm inversion electricity with neutral point is made of the identical insulated gate bipolar transistor of 8 specifications Road；First filter and second filter are made of the identical inductance of three inductance values and the identical capacitor of capacitance.

Technical field

The present invention relates to field of power electronics more particularly to a kind of high power density non-isolated photovoltaic grid-connected inverters.

Background technique

With being constantly progressive for human civilization, energy demand is being continuously increased, the non-renewable energy based on fossil fuel It sharply reduces in source.Also, largely aggravates global warming using fossil fuel, deteriorate natural environment.It finds green, environmental protection Renewable energy by be facing mankind a huge challenge.The green regenerative energy sources that solar energy is nexhaustible as one kind, Highest attention of the photovoltaic power generation by national governments, is wideling popularize photovoltaic power generation industry all over the world.

Core apparatus of the photovoltaic DC-to-AC converter as photovoltaic power generation, so that the volume and cost of photovoltaic combining inverter are directly made About the popularization of photovoltaic power generation industry.Currently, conventional photovoltaic gird-connected inverter is made using three-phase isolated form Split winding transformer For grid-connected transformer, lead to that photovoltaic combining inverter is bulky, power density is low, expensive.

Summary of the invention

The technical problem to be solved by the embodiment of the invention is that it is grid-connected to provide a kind of high power density non-isolation type Inverter, so as to improve power quality.

In order to solve the above-mentioned technical problem, it is grid-connected to propose a kind of high power density non-isolation type for the embodiment of the present invention Inverter, including the first photovoltaic array, the second photovoltaic array, the first three-phase inverter, the second three-phase inverter, the first filtering Device, second filter and grid-connected transformer, the first photovoltaic array, the first three-phase inverter, first filter are sequentially connected, and second Photovoltaic array, the second three-phase inverter, second filter are sequentially connected, grid-connected transformer and first filter and second filter Output end connection, grid-connected transformer is by the first single-phase three-winding autotransformer, the second single-phase three-winding autotransformer, the Three single-phase three-winding autotransformers composition, three single-phase three-winding autotransformer winding constructions of grid-connected transformer are using shifting Phase multiple connection mode.

Further, structure, the specification of first photovoltaic array and the second photovoltaic array are identical, the first three-phase inverter Identical with the structure of the second three-phase inverter, specification, first filter is identical with structure, the specification of second filter；First light The output head anode of photovoltaic array and the second photovoltaic array input terminal with the first three-phase inverter and the second three-phase inverter respectively Anode connection, the negative pole of output end of the first photovoltaic array and the second photovoltaic array respectively with the first three-phase inverter and the second three-phase The input cathode of inverter connects, and the three-phase output end of the first three-phase inverter and the second three-phase inverter is filtered with first respectively Wave device is connected with the three-phase input end of second filter；The a phase output terminal of first filter and the second single-phase three winding self coupling become The input terminal of the a1 winding of depressor is connected, the b phase output terminal of first filter and the b1 of third single-phase three-winding autotransformer The input terminal of winding is connected, the c1 winding of the c phase output terminal and the first single-phase three-winding autotransformer of first filter it is defeated Enter end to be connected；The input terminal of the a2 winding of a phase output terminal and the second single-phase three-winding autotransformer of second filter is connected, The input terminal of the b2 winding of the b phase output terminal and third single-phase three-winding autotransformer of second filter is connected, the second filtering The input terminal of the c2 winding of the c phase output terminal and the first single-phase three-winding autotransformer of device is connected.

Further, the first single-phase three-winding autotransformer, the second single-phase three-winding autotransformer, third single-phase three The structure of winding autotransformer is identical, is made of two stems of the first stem and the second stem, the first stem, the first stem For the first primary side winding and the second primary side winding, the second stem is public winding, the first primary side winding and the second primary side winding pair Answering the number of turns is respectively N1 and N2, and it is N3 that public winding, which corresponds to the number of turns, and the turn ratio between three windings is N1:N2:N3=0.1547: 0.1547:1.

Further, two primary side winding of the first single-phase three-winding autotransformer output end be connected, second single-phase three around The output end of group two primary side winding of auto-transformer is connected, the output end of two primary side winding of third single-phase three-winding autotransformer It is connected, the secondary side of the first, second third single-phase three-winding autotransformer is all made of triangle junction, and the first single-phase three winding is certainly The output end and power grid a phase of the first end of coupling transformer secondary winding and two primary side winding of the second single-phase three-winding autotransformer Be connected, the second end of the first single-phase three-winding autotransformer vice-side winding and the second single-phase three-winding autotransformer pair side around The first end of group is connected；The single-phase three winding self coupling of first end and third of second single-phase three-winding autotransformer vice-side winding becomes The output end and power grid b phase of two primary side winding of depressor are connected, the second end of the second single-phase three-winding autotransformer vice-side winding It is connected with the first end of third single-phase three-winding autotransformer vice-side winding；Third single-phase three-winding autotransformer pair side around The first end of group is connected with the output end of two primary side winding of the first single-phase three-winding autotransformer and power grid c phase, and third is single-phase The first end phase of the second end of three-winding autotransformer vice-side winding and the first single-phase three-winding autotransformer vice-side winding Even.

Further, there are 30 ° of phases for the phase voltage of the in-phase output end of the first three-phase inverter and the second three-phase inverter Potential difference.

Further, the first photovoltaic array and the second photovoltaic array are by the identical photovoltaic cell plate serioparallel of multiple specifications Composition；First three-phase inverter and the second three-phase inverter include being made of the identical insulated gate bipolar transistor of 8 specifications Three-phase four-arm inverter circuit with neutral point；First filter and second filter by the identical inductance of three inductance values and The identical capacitor of capacitance is constituted.

The invention has the benefit that the present invention is using single-phase three-winding autotransformer as photovoltaic combining inverter Grid-connected transformer, so that the capacity of grid-connected transformer reduces compared with using traditional Industrial Frequency Transformer in photovoltaic combining inverter 82%, the power density of photovoltaic combining inverter greatly improves, umber of turn is reduced, save the cost；Three single-phase three winding self couplings Transformer winding structure uses phase shift multiple connection mode, when two groups of photovoltaic array parallel runnings, controls two groups using SPWM Three-phase inverter will inhibit special so that there are 30 ° of phase differences for voltage between two primary side windings of the same phase of filter output Subharmonic grid-connected current is levied, power quality is improved.

Detailed description of the invention

Fig. 1 is the high power density non-isolated photovoltaic grid-connected inverter of the embodiment of the present invention in two groups of photovoltaic arrays works Structural schematic diagram when making.

Fig. 2 is the high power density non-isolated photovoltaic grid-connected inverter of the embodiment of the present invention in only the first photovoltaic array Schematic diagram when operation.

Fig. 3 is the high power density non-isolated photovoltaic grid-connected inverter of the embodiment of the present invention in only the second photovoltaic array Structural schematic diagram when operation.

Fig. 4 is the first three-phase inverter and first filter circuit structure diagram of the embodiment of the present invention.

Fig. 5 is the second three-phase inverter and second filter circuit structure diagram of the embodiment of the present invention.

Fig. 6 is the phasor diagram of three single-phase three-winding autotransformer winding couplings of the embodiment of the present invention.

Specific embodiment

It should be noted that in the absence of conflict, the features in the embodiments and the embodiments of the present application can phase It mutually combines, invention is further described in detail in the following with reference to the drawings and specific embodiments.

If directional instruction (such as up, down, left, right, before and after ...) is only used for explaining at certain in the embodiment of the present invention Relative positional relationship, motion conditions etc. under one particular pose (as shown in the picture) between each component, if the particular pose is sent out When raw change, then directionality instruction also correspondingly changes correspondingly.

If in addition, the description for being related to " first ", " second " etc. in the present invention is used for description purposes only, and should not be understood as Its relative importance of indication or suggestion or the quantity for implicitly indicating indicated technical characteristic.Define as a result, " first ", The feature of " second " can explicitly or implicitly include at least one of the features.

FIG. 1 to FIG. 6 is please referred to, the high power density non-isolated photovoltaic grid-connected inverter of the embodiment of the present invention includes first Photovoltaic array 1, the second photovoltaic array 2, the first three-phase inverter 3, the second three-phase inverter 4, first filter 5, second filter Device 6 and grid-connected transformer.

First photovoltaic array 1, the first three-phase inverter 3, first filter 5 are sequentially connected, the second photovoltaic array 2, second Three-phase inverter 4, second filter 6 are sequentially connected, the output end of grid-connected transformer and first filter 5 and second filter 6 Connection, grid-connected transformer are single-phase by the first single-phase three-winding autotransformer 7, the second single-phase three-winding autotransformer 8, third Three-winding autotransformer 9 forms, and three single-phase three-winding autotransformer winding constructions of grid-connected transformer are more using phase shift Weight bind mode.

As an implementation, the first photovoltaic array 1 is identical with structure, the specification of the second photovoltaic array 2, the first three-phase Inverter 3 is identical with structure, the specification of the second three-phase inverter 4, structure, the specification phase of first filter 5 and second filter 6 Together；The output head anode of first photovoltaic array 1 and the second photovoltaic array 2 respectively with the first three-phase inverter 3 and the two or three contrary Become the input anode connection of device 4, the negative pole of output end of the first photovoltaic array 1 and the second photovoltaic array 2 respectively with the first three-phase Inverter 3 is connected with the input cathode of the second three-phase inverter 4, and the three of the first three-phase inverter 3 and the second three-phase inverter 4 Phase output terminal is connect with the three-phase input end of first filter 5 and second filter 6 respectively；The a phase output terminal of first filter 5 A1 is connected with the input terminal of the a1 winding of the second single-phase three-winding autotransformer 8, the b phase output terminal b1 of first filter 5 with The input terminal of the b1 winding of third single-phase three-winding autotransformer 9 is connected, the c phase output terminal c1 of first filter 5 and first The input terminal of the c1 winding of single-phase three-winding autotransformer 7 is connected；The a phase output terminal a2 of second filter 6 and second is single-phase The input terminal of the a2 winding of three-winding autotransformer 8 is connected, the b phase output terminal b2 of second filter 6 and third single-phase three around The input terminal of the b2 winding of group auto-transformer 9 is connected, and the single-phase three winding of the c phase output terminal c2 of second filter 6 and first is certainly The input terminal of the c2 winding of coupling transformer 7 is connected.

As an implementation, the first single-phase three-winding autotransformer 7, the second single-phase three-winding autotransformer 8, The structure of third single-phase three-winding autotransformer 9 is identical, is made of two stems of the first stem and the second stem, the first core Column, the first stem are the first primary side winding and the second primary side winding, and the second stem is public winding, the first primary side winding and second It is respectively N1 and N2 that primary side winding, which corresponds to the number of turns, and it is N3 that public winding, which corresponds to the number of turns, and the turn ratio between three windings is N1:N2: N3=0.1547:0.1547:1.

As an implementation, the output end of two primary side windings of the first single-phase three-winding autotransformer 7 is connected, the The output end of two primary side windings of two single-phase three-winding autotransformers 8 is connected, and the two of third single-phase three-winding autotransformer 9 The output end of primary side winding is connected, and the secondary side of the first, second, third single-phase three-winding autotransformer is all made of triangle connection The two of knot, the first end of 7 vice-side winding of the first single-phase three-winding autotransformer and the second single-phase three-winding autotransformer 8 are former The output end and power grid a phase of side winding are connected, and the second end of 7 vice-side winding of the first single-phase three-winding autotransformer is single with second The first end of 8 vice-side winding of phase three-winding autotransformer is connected；The of second single-phase three-winding autotransformer, 8 vice-side winding One end is connected with the output end of two primary side windings of third single-phase three-winding autotransformer 9 and power grid b phase, second single-phase three around The second end of group 8 vice-side winding of auto-transformer is connected with the first end of 9 vice-side winding of third single-phase three-winding autotransformer； Two primary sides of the first end of 9 vice-side winding of third single-phase three-winding autotransformer and the first single-phase three-winding autotransformer 7 The output end and power grid c phase of winding are connected, the second end of 9 vice-side winding of third single-phase three-winding autotransformer and first single-phase The first end of 7 vice-side winding of three-winding autotransformer is connected.

As an implementation, the first three-phase inverter 3 and the second three-phase inverter 4 use SPWM control method, make There are 30 ° of phase differences for the phase voltage of the in-phase output end of first three-phase inverter 3 and the second three-phase inverter 4, are sent into three lists After phase three-winding autotransformer, harmonics grid-connected current can inhibit, improve power quality.First photovoltaic battle array of the invention Column 1 and the second photovoltaic array 2 can parallel running, can also there was only the first photovoltaic array 1 or the operation of the second photovoltaic array 2.When two groups When the first photovoltaic array 1 and the second 2 parallel running of photovoltaic array, two originals of same phase of two filter outputs of the invention Voltage is there are 30 ° of phase differences between the winding of side, be sent into after three single-phase three-winding autotransformers will inhibitory character subharmonic simultaneously Net electric current improves power quality；When only the first photovoltaic array 1 or the second photovoltaic array 2 are run, of the invention single-phase three around Group auto-transformer is equivalent to single-phase two winding autotransformer.

As an implementation, the first photovoltaic array 1 and the second photovoltaic array 2 are by the identical photovoltaic electric of multiple specifications Pond plate serioparallel composition.First three-phase inverter 3 and the second three-phase inverter 4 are all made of three-phase four-arm structure, the first three-phase Converter 3 and the second three-phase inverter 4 include that band neutrality is made of the identical insulated gate bipolar transistor (IGBT) of 8 specifications Point three-phase four-arm inverter circuit (the first three-phase inverter 3 by insulated gate bipolar transistor S1, S2, S3, S4, S5, S6, S7, S8 composition, the second three-phase inverter 4 are made of insulated gate bipolar transistor S9, S10, S11, S12, S13, S14, S15, S16). The inductance identical by three inductance values with second filter 6 of first filter 5 and the identical capacitor of capacitance are constituted.

As an implementation, first filter 5 includes the first filter inductance L1, the second filter inductance L2, third filter Wave inductance L3, the first filter capacitor C1, the second filter capacitor C2 and third filter capacitor C3, a of first three-phase inverter 3 Phase output terminal is connect with the left end of the first filter inductance L1, the b phase output terminal of the first three-phase inverter 3 and the second filter inductance L2 Left end connection, the c phase output terminal of the first three-phase inverter 3 connect with the left end of third filter inductance L3, the first filter inductance The right end of L1 connect with the first end of the first filter capacitor C1, the second end of the first filter capacitor C1 and the first three-phase inverter 3 Central point n connection, the right end of the second filter inductance L2 connect with the first end of the second filter capacitor C2, the second filter capacitor C2 Second end connect with the central point n of the first three-phase inverter 3, the right end of third filter inductance L3 and third filter capacitor C3's First end connects, the second end of third filter capacitor C3 is connect with the central point n of the first three-phase inverter 3；Two or three phase inversion The a phase output terminal of device 4 is connect with the left end of the 4th filter inductance L4, the b phase output terminal of the second three-phase inverter 4 and the 5th filtering The left end of inductance L5 connects, and the c phase output terminal of the second three-phase inverter 4 is connect with the left end of the 6th filter inductance L6, the 4th filter The right end of wave inductance L4 connect with the first end of the 4th filter capacitor C4, the second end of the 4th filter capacitor C4 and the two or three phase transformation The central point n connection of parallel operation 4, the right end of the 5th filter inductance L5 is connect with the first end of the 5th filter capacitor C5, the 5th filters The second end of capacitor C5 is connect with the central point n of the second three-phase inverter 4, the right end and the 6th filtered electrical of the 6th filter inductance L6 The second end of the first end connection, the 6th filter capacitor C6 of holding C6 is connect with the central point n of the second three-phase inverter 4.

Scheme provided in an embodiment of the present invention be suitable for two groups of photovoltaic array parallel runnings or single group photovoltaic array operation or Multiple groups photovoltaic array parallel running, feelings when two groups of photovoltaic array parallel runnings are described below and when single group photovoltaic array is run Condition.