CN209748195U - Single-phase nonlinear filter and three-phase nonlinear filter - Google Patents

Single-phase nonlinear filter and three-phase nonlinear filter Download PDF

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Publication number
CN209748195U
CN209748195U CN201920988574.2U CN201920988574U CN209748195U CN 209748195 U CN209748195 U CN 209748195U CN 201920988574 U CN201920988574 U CN 201920988574U CN 209748195 U CN209748195 U CN 209748195U
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inductor
nonlinear filter
phase
phase nonlinear
capacitor
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郑庆杰
炊天鹄
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Hefei Yunlu Juneng Electric Co ltd
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Qingdao Yun Lu Electric Power Co Ltd
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    • 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
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

Abstract

A single-phase nonlinear filter and a three-phase nonlinear filter, the single-phase nonlinear filter comprising: the circuit comprises a first input end, a second input end, a first inductor, a first capacitor, a first output end and a second output end, wherein one end of the first inductor is connected with the first input end, one end of the first capacitor is connected with the other end of the first inductor and the first output end, the other end of the first capacitor is connected with the second input end and the second output end, and the first inductor is a nonlinear inductor; the three-phase nonlinear filter comprises three single-phase nonlinear filters, wherein the first input end of each single-phase nonlinear filter is one phase of the three phases, and the second input end and the second output end of each single-phase nonlinear filter are connected together to form a neutral point of the three phases.

Description

Single-phase nonlinear filter and three-phase nonlinear filter
Technical Field
The utility model relates to a wave filter technical field that the inverter was used especially relates to a single-phase nonlinear filter and three-phase nonlinear filter.
Background
As energy consumption and environmental protection issues become more of a concern, the development of inverters, particularly photovoltaic inverters, is active. The photovoltaic inverter is a power electronic device connected between a solar panel and a power grid (see fig. 1), and mainly functions to convert direct current generated by the solar panel into alternating current capable of being connected to the grid through a power module, and is one of core devices in a photovoltaic system.
In consideration of the actual situation of photovoltaic power generation, different loads are different in daily illumination, and in order to ensure daily power generation, the efficiency in the light load stage is also considered, so that an efficiency weight and European efficiency calculation method based on different loads is provided, and the method specifically comprises the following steps:
Overall efficiency of 0.03 × 5% load efficiency +0.06 × 10% load efficiency +0.13 × 20% load efficiency +0.1 × 30% load efficiency +0.48 × 50% load efficiency +0.2 × 100% load efficiency
As can be seen from the above calculation of the overall efficiency, in order to obtain higher overall efficiency, the photovoltaic system should pay attention to not only the heavy load efficiency but also the light load efficiency.
In addition, the output waveform distortion of the photovoltaic inverter can affect the quality of a power grid, the output current waveform distortion of the general photovoltaic inverter is particularly serious under light load, and corresponding specifications make requirements on grid-connected harmonics, so that the reduction of the output current waveform distortion of the photovoltaic inverter under light load is very important.
In the prior art, a dual-filter technology (see fig. 2) is used for improving light load efficiency and output current waveform distortion during light load, but two active filters are adopted, each active filter comprises two switching devices, an inductor and a capacitor, and each switching device needs a corresponding monitoring and control module, so that the defects of high cost, large volume, complex control, low reliability and the like exist.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problem, the utility model discloses a single-phase nonlinear filter's technical scheme:
A single-phase nonlinear filter comprising: the inductor comprises a first input end, a second input end, a first inductor, a first capacitor, a first output end and a second output end, wherein one end of the first inductor is connected with the first input end, one end of the first capacitor is connected with the other end of the first inductor and the first output end, the other end of the first capacitor is connected with the second input end and the second output end, and the first inductor is a nonlinear inductor.
Furthermore, the single-phase nonlinear filter further comprises a second inductor, the second inductor is connected between the second input end and the other end of the first capacitor, and the second inductor is a common inductor or a nonlinear inductor.
Further, the single-phase nonlinear filter further comprises a third inductor, the third inductor is connected between the first output end and one end of the first capacitor, and the third inductor is a common inductor or a nonlinear inductor.
Further, the single-phase nonlinear filter further comprises a fourth inductor and a fifth inductor, wherein the fourth inductor is connected between the first output end and one end of the first capacitor, and the fifth inductor is connected between the second output end and the other end of the first capacitor.
Further, the fourth inductor or/and the fifth inductor are nonlinear inductors.
Furthermore, the composite magnetic core is formed by connecting a high Bs magnetic core and a low Bs magnetic core in series.
In order to achieve the above object, the utility model also discloses a three-phase nonlinear filter's technical scheme:
A three-phase nonlinear filter comprises three single-phase nonlinear filters, wherein the first input end of each single-phase nonlinear filter is one phase of the three phases, and the other ends of the first capacitors of each single-phase nonlinear filter are connected together to form a neutral point of the three phases.
further, the nonlinear inductor is a unitary inductor with a single one of the characteristics of a non-uniform air gap, a combined magnetic core, a non-uniform magnetic core cross-sectional area, a flux non-uniformity compensation permanent magnet, a composite magnetic core, or an integrated inductor with multiple ones of the characteristics.
Furthermore, the nonlinear inductor is formed by connecting a large-current low-inductance inductor and a low-current high-inductance inductor in series.
The beneficial effects of the utility model are that, the utility model discloses a single-phase nonlinear filter and three-phase nonlinear filter has adopted nonlinear inductance, can effectively restrain underloading harmonic, improves efficiency when underloading to have with low costs, small advantage.
Drawings
The present invention will be further explained with reference to the drawings and examples.
Fig. 1 is a schematic diagram of a photovoltaic system of prior art solar panel, photovoltaic inverter and grid configurations.
Fig. 2 is a schematic diagram of the photovoltaic system of fig. 1 with dual filters between the photovoltaic inverter and the grid.
Fig. 3 is a diagram showing the relationship between the inductance value and the current of a general inductor.
Fig. 4 is a diagram showing the relationship between the inductance value and the current of the nonlinear inductor.
Fig. 5 is a single-phase nonlinear filter according to the first embodiment.
Fig. 6 is a single-phase nonlinear filter according to the second embodiment.
Fig. 7 is a single-phase nonlinear filter according to the third embodiment.
Fig. 8 is a single-phase nonlinear filter according to the fourth embodiment.
Fig. 9 is a three-phase nonlinear filter of the fifth embodiment.
Fig. 10 is a three-phase nonlinear filter according to the sixth embodiment.
Fig. 11 is a unitary inductor with a non-uniform air gap.
FIGS. 12-a through 12-l illustrate twelve different non-uniform air gap shapes.
Fig. 13 is a unitary inductor with a merged core feature.
Fig. 14 is a unitary inductor with non-uniform core cross-sectional area.
Fig. 15 is a unitary inductor with flux non-uniformity compensating permanent magnet features.
fig. 16 is a unitary inductor with a composite magnetic core feature.
Fig. 17 is an integrated inductor featuring both non-uniform air gap and composite core.
Detailed Description
example one
A single-phase nonlinear filter according to a first embodiment shown in fig. 5, comprising: the inductor comprises a first input end, a second input end, a first inductor, a first capacitor, a first output end and a second output end, wherein one end of the first inductor is connected with the first input end, one end of the first capacitor is connected with the other end of the first inductor and the first output end, the other end of the first capacitor is connected with the second input end and the second output end, and the first inductor is a nonlinear inductor.
Compared with the common inductor, the nonlinear inductor has larger initial inductance under the condition of lighter load, so that the single-phase nonlinear filter has better filtering effect under the condition of light load, after the nonlinear inductor is applied to a photovoltaic system (the single-phase nonlinear filter is positioned between the photovoltaic inverter and a power grid), the waveform distortion of the output current of the photovoltaic inverter is improved, the efficiency under the light load is improved, the harmonic wave of the power grid is improved, and the grid connection is facilitated.
The non-linear inductor may be a single inductor having a single characteristic of the non-uniform air gap, the non-uniform core cross-sectional area, the flux non-uniformity compensation permanent magnet, and the composite core, or an integrated inductor having any two or more of these characteristics, for example, fig. 17 shows an integrated inductor having both the non-uniform air gap and the composite core.
Fig. 11 shows a unitary inductor with non-uniform air gap, which is composed of a magnetic core, a coil and an air gap, wherein the overall shape of the magnetic core can be rectangular, circular arc, etc.; the air gap is a single-step non-uniform air gap, and the shape of the air gap of the unitary inductor of the non-uniform air gap may be several shapes as shown in fig. 12-a to 12-l, such as a convex shape of the cross-sectional area of the air gap as shown in fig. 12-a, a concave shape of the cross-sectional area of the air gap as shown in fig. 12-b, a trapezoid shape of the cross-sectional area of the air gap as shown in fig. 12-c, and so on, in addition to the shape shown in fig. 11.
Fig. 13 shows a unitary inductor with a combined core feature, in which the first core and the second core have different saturation densities, for example, the first core is a low saturation density core, and the second core is a high saturation density core (relative to the concept, the saturation densities are different by more than 0.2 tesla), and as the load increases, the first core with the low saturation density reaches saturation first to achieve the adjustment of the inductance; the shapes of the first magnetic core and the second magnetic core can be square, elliptical, and the like, besides the circular ring shape shown in fig. 13.
Fig. 14 shows a unitary inductor having a non-uniform core cross-sectional area, which is composed of a core and a coil, and the shape of the core is a zigzag rotated by 90 degrees, in which the sum of the core cross-sectional areas on both sides (a1+ a2) is larger than the center core cross-sectional area B.
Fig. 15 shows a unitary inductor with flux-unevenness compensation permanent-magnet characteristics, which is composed of a magnetic core, a coil, permanent magnets, and an air gap (which is a uniform air gap), wherein the overall shape of the magnetic core is a shape of a Chinese character ri rotated by 90 degrees, two sections of the permanent magnets are disposed at two ends of the middle of the magnetic core, and the coil is wound around two sides of the magnetic core.
Fig. 16 shows a unitary inductor featuring a composite magnetic core consisting of a magnetic core, a coil and an air gap (uniform air gap), wherein the magnetic core is formed by connecting a high Bs (saturation magnetic flux density) magnetic core and a low Bs magnetic core in series.
In addition, the non-linear inductor can be a series connection of a large-current low-inductance inductor and a low-current high-inductance inductor (the large current and the low current are relative concepts, particularly the current difference between the two is more than two times, and the low inductance and the high inductance are relative concepts, particularly the inductance difference between the two is more than two times), so that when the load is increased, the low-current high-inductance inductor is saturated preferentially to realize inductance adjustment.
Example two
Compared with the single-phase nonlinear filter of the first embodiment shown in fig. 5, the single-phase nonlinear filter of the second embodiment shown in fig. 6 is different in that the single-phase nonlinear filter of the second embodiment shown in fig. 6 further includes a second inductor, and the second inductor is connected between the second input terminal and the other end of the first capacitor.
The second inductor may be a common inductor or a nonlinear inductor (the nonlinear inductor may be any one of the forms mentioned in the first embodiment); when the second inductor is a nonlinear inductor, the common-mode current suppression effect of the single-phase nonlinear filter is better.
EXAMPLE III
Compared with the single-phase nonlinear filter of the first embodiment shown in fig. 5, the single-phase nonlinear filter of the third embodiment shown in fig. 7 is different in that the single-phase nonlinear filter of the third embodiment shown in fig. 7 further includes a third inductor, the third inductor is connected between the first output terminal and one end of the first capacitor, and the third inductor is added, so that the noise suppression effect of the single-phase nonlinear filter is better.
The third inductor may be a common inductor or a nonlinear inductor (the nonlinear inductor may be any one of the forms mentioned in the first embodiment).
Example four
A single-phase nonlinear filter according to a fourth embodiment shown in fig. 8 is different from the single-phase nonlinear filter according to the second embodiment shown in fig. 6 in that the single-phase nonlinear filter according to the fourth embodiment shown in fig. 8 further includes a fourth inductor and a fifth inductor, the fourth inductor is connected between the first output terminal and one end of the first capacitor, and the fifth inductor is connected between the second output terminal and the other end of the first capacitor.
The fourth inductor and the fifth inductor may be ordinary inductors or nonlinear inductors (the nonlinear inductor may be any one of the forms mentioned in the first embodiment).
EXAMPLE five
Fig. 9 shows a three-phase nonlinear filter according to a fifth embodiment, which includes three single-phase nonlinear filters according to the first embodiment, wherein the first input terminal of each single-phase nonlinear filter is one of the three phases, and the second input terminal and the second output terminal of each single-phase nonlinear filter are connected together to form a neutral point of the three phases.
EXAMPLE six
Fig. 10 shows a three-phase nonlinear filter according to a sixth embodiment, which includes three single-phase nonlinear filters according to the third embodiment, wherein the first input terminal of each single-phase nonlinear filter is one of the three phases, and the other terminals of the first capacitor of each single-phase nonlinear filter are connected together to form a neutral point of the three phases.
Specific embodiments of the present invention have been described above in detail. It is to be understood that the embodiments of the present invention are not limited to these examples, which are merely described to assist understanding of the spirit of the present invention. All changes made to the invention within the spirit of the disclosure are intended to be encompassed by the invention. The scope of the present invention should be defined by the appended claims.

Claims (10)

1. A single-phase nonlinear filter comprising: the inductor comprises a first input end, a second input end, a first inductor, a first capacitor, a first output end and a second output end, and is characterized in that one end of the first inductor is connected with the first input end, one end of the first capacitor is connected with the other end of the first inductor and the first output end, the other end of the first capacitor is connected with the second input end and the second output end, and the first inductor is a nonlinear inductor.
2. The single-phase nonlinear filter of claim 1 further comprising a second inductor, wherein the second inductor is connected between the second input terminal and the other end of the first capacitor, and the second inductor is a common inductor or a nonlinear inductor.
3. The single-phase nonlinear filter of claim 1 further comprising a third inductor, wherein the third inductor is connected between the first output terminal and one end of the first capacitor, and the third inductor is a common inductor or a nonlinear inductor.
4. The single-phase nonlinear filter of claim 2 further comprising a fourth inductor and a fifth inductor, wherein the fourth inductor is connected between the first output terminal and one end of the first capacitor, and the fifth inductor is connected between the second output terminal and the other end of the first capacitor.
5. The single-phase nonlinear filter of claim 4, wherein the fourth inductor or/and the fifth inductor is a nonlinear inductor.
6. The single-phase nonlinear filter of any one of claims 1 to 5, wherein the nonlinear inductor is a unitary inductor having a single one of several characteristics of a non-uniform air gap, a parallel core, a non-uniform core cross-sectional area, a flux-non-uniformity compensation permanent magnet, a composite core, or an integrated inductor having a plurality of these several characteristics.
7. The single-phase nonlinear filter of claim 6 wherein the composite magnetic core is formed by connecting high Bs magnetic cores and low Bs magnetic cores in series.
8. The single-phase nonlinear filter recited in any one of claims 1 to 5 wherein the nonlinear inductor is formed by connecting a high current low inductance inductor and a low current high inductance inductor in series.
9. A three-phase nonlinear filter, comprising three single-phase nonlinear filters as claimed in claim 1 and claim 3, wherein the first input terminal of each single-phase nonlinear filter is one of the three phases, and the other terminals of the first capacitor of each single-phase nonlinear filter are connected together to form a neutral point of the three phases.
10. The three-phase nonlinear filter of claim 9, wherein the nonlinear inductor is a unitary inductor having a single one of the several characteristics of a non-uniform air gap, a parallel core, a non-uniform core cross-sectional area, a flux-non-uniformity compensation permanent magnet, a composite core, or an integrated inductor having multiple ones of the several characteristics; or a high-current low-inductance inductor and a low-current high-inductance inductor are connected in series.
CN201920988574.2U 2019-06-28 2019-06-28 Single-phase nonlinear filter and three-phase nonlinear filter Active CN209748195U (en)

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Effective date of registration: 20221020

Address after: 2# workshop, Hefei Huilip Motor Co., Ltd., west of Fenghua West Road, Taohua Industrial Park, Hefei City, Anhui Province, 231200

Patentee after: Hefei Yunlu Juneng Electric Co.,Ltd.

Address before: 266000 No. 97 Yanyang Road, Chengyang District, Qingdao City, Shandong Province

Patentee before: QINGDAO YUNLU JUNENG ELECTRIC Co.,Ltd.

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