A current-type twelve-pulse rectifier phase-shifting reactor and system

Abstract

The present invention designs a current-type twelve-pulse rectifier phase-shifting reactor and system, and at the same time adopts a magnetic integration form to increase an integrated filter inductor. In the structure of the current-type phase-shifting reactor, any two phases are insulated from each other, solving the problem of leakage current under no-load conditions. By adjusting the turn ratio of the phase-shifting reactor, the current of each rectifier bridge arm can also be made equal, simplifying the device selection. The highly integrated filter inductor reduces the consumption of magnetic materials, reduces the magnetic material loss, and at the same time reduces the device installation complexity.

Description

Technical Field

[0001] The present invention relates to the technical field of passive multi-pulse rectification, and particularly to a current-type twelve-pulse rectifier phase-shifting reactor and system. Background Art

[0002] As is well known to those skilled in the art, the input current of a rectifier circuit is non-sinusoidal, and the current contains a large number of high-order harmonics. In order to reduce harmonic pollution to the power grid and improve the input power factor, the number of pulses of the rectifier circuit can be increased in a three-phase power system. When using a multi-pulse rectification method, it can be solved by a phase-shifting method. Usually, a phase-shifting transformer such as a symmetric type, an asymmetric type, an isolation type, or an autotransformer type is used to achieve the phase-shifting. The phase-shifting purpose of these various phase-shifting transformers is to obtain a voltage phase-shifting angle suitable for rectification. For example, a 12-pulse rectifier circuit requires a voltage phase-shifting angle of 30°, an 18-pulse rectifier circuit requires a voltage phase-shifting angle of 20°, a 24-pulse rectifier circuit requires a voltage phase-shifting angle of 15°, and so on.

[0003] However, traditional multi-pulse rectification uses the phase-shifting angle of the voltage waveform as a reference to form a current closer to a sinusoidal waveform after superimposing three-phase currents, so as to reduce the content of high-order harmonics and improve the input power factor. The implementation method is an autotransformer type or an isolation type, and it is impossible to avoid the mutual connection between the input voltages L1, L2, and L3 through the transformer coils, resulting in the existence of leakage current between the three phases under no-load conditions. At the same time, due to the existence of the transformer structure, its performance is greatly affected by voltage fluctuations and frequency waveforms. The overall volume and weight are relatively large, the cost is high, and when further improving the input current waveform data, an additional inductor is usually added to further suppress high-order harmonic currents, making the equipment larger in volume and weight and more complex to install. Summary of the Invention

[0004] The object of the present invention is to provide a current-type twelve-pulse rectifier phase-shifting reactor and system, which can not only solve the problem of leakage current under no-load conditions, but also reduce the loss of magnetic materials and simplify the complexity of device installation.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] A current-type twelve-pulse rectifier phase-shifting reactor includes an iron core and a plurality of windings;

[0007] The iron core includes an upper yoke, a middle yoke, and a lower yoke, and the upper yoke and the middle yoke, and the middle yoke and the lower yoke are respectively connected by magnetic columns;

[0008] The windings are divided into three phases and wound on the magnetic columns. The windings are connected independently according to each phase, and the winding structure makes the phase-shifting angle of the output current of each phase in two groups be 30°.

[0009] Furthermore, there are five magnetic columns between the middle yoke and the lower yoke, which are defined as the first magnetic column, the second magnetic column, the third magnetic column, the fourth magnetic column, and the fifth magnetic column from left to right. There are three magnetic columns between the upper yoke and the middle yoke, which are defined as the sixth magnetic column, the seventh magnetic column, and the eighth magnetic column from left to right;

[0010] Each phase has four windings, for a total of twelve windings. The four windings of phase A are respectively defined as winding A0, winding A1, winding A2, and winding A3; the four windings of phase B are respectively defined as winding B0, winding B1, winding B2, and winding B3; the four windings of phase C are respectively defined as winding C0, winding C1, winding C2, and winding C3;

[0011] Three windings, namely A1, C2, and C3, are wound on the first magnetic column; three windings, namely B1, A2, and A3, are wound on the third magnetic column; three windings, namely C1, B2, and B3, are wound on the fifth magnetic column; winding A0 is wound on the sixth magnetic column; winding B0 is wound on the seventh magnetic column; winding C0 is wound on the eighth magnetic column. There are no windings on the second and fourth magnetic columns.

[0012] Furthermore, the connection relationship of the twelve windings is as follows:

[0013] One end of winding A0 is connected to one end of winding A1, and the other end of winding A1 is simultaneously connected to winding A2 and winding A3;

[0014] One end of winding B0 is connected to one end of winding B1, and the other end of winding B1 is simultaneously connected to winding B2 and winding B3;

[0015] One end of winding C0 is connected to one end of winding C1, and the other end of winding C1 is simultaneously connected to winding C2 and winding C3.

[0016] Furthermore, there is an air gap left between the upper yoke and the magnetic columns.

[0017] Furthermore, the middle yoke and the magnetic columns, as well as the lower yoke and the magnetic columns, are connected in a cross-laminated manner without leaving an air gap.

[0018] Furthermore, the winding turn ratio relationship is as follows:

[0019]

[0020]

[0021] Among them, is the number of turns of windings A1, B1, and C1, is the number of turns of windings A2, B2, and C2, is the number of turns of windings A3, B3, and C3.

[0022] Furthermore, the winding turn ratio relationship is as follows:

[0023]

[0024] Among them, are the number of turns of windings A0, B0, and C0.

[0025] A current-type twelve-pulse rectifier phase-shifting reactor system includes any current-type twelve-pulse rectifier phase-shifting reactor as described in claims 1-7 and a twelve-pulse rectifier bridge. The input of the current-type twelve-pulse rectifier phase-shifting reactor is electrically connected to a three-wire input, and six groups of currents are output, which are respectively connected to the midpoints of the six bridge arms of the twelve-pulse rectifier bridge. Capacitors are connected in parallel at both ends of the twelve-pulse rectifier bridge, and both ends of the capacitors are connected to a load.

[0026] Further, there are a total of twelve windings, with four windings in each phase. The four windings of phase A are respectively defined as winding A0, winding A1, winding A2, and winding A3; the four windings of phase B are respectively defined as winding B0, winding B1, winding B2, and winding B3; the four windings of phase C are respectively defined as winding C0, winding C1, winding C2, and winding C3;

[0027] The U line of the three-phase power is connected to one end of winding A0, the other end of winding A0 is connected to one end of winding A1, the other end of winding A1 is simultaneously connected to winding A2 and winding A3, the other end of winding A2 is connected to the midpoint of the fourth bridge arm of the twelve-pulse rectifier bridge, and the other end of winding A3 is connected to the midpoint of the third bridge arm of the twelve-pulse rectifier bridge;

[0028] The V line of the three-phase power is connected to one end of winding B0, the other end of winding B0 is connected to one end of winding B1, the other end of winding B1 is simultaneously connected to winding B2 and winding B3, the other end of winding B2 is connected to the midpoint of the sixth bridge arm of the twelve-pulse rectifier bridge, and the other end of winding B3 is connected to the midpoint of the fifth bridge arm of the twelve-pulse rectifier bridge;

[0029] The W line of the three-phase power is connected to one end of winding C0, the other end of winding C0 is connected to one end of winding C1, the other end of winding C1 is simultaneously connected to winding C2 and winding C3, the other end of winding C2 is connected to the midpoint of the second bridge arm of the twelve-pulse rectifier bridge, and the other end of winding C3 is connected to the midpoint of the first bridge arm of the twelve-pulse rectifier bridge;

[0030] The twelve-pulse rectifier bridge has six bridge arms, and the connection point of two series-connected thyristors on each bridge arm is the midpoint of the bridge arm.

[0031] The advantages of the present invention are as follows: A three-phase current-type twelve-pulse rectifier phase-shifting reactor system is provided, and an integrated filter inductor is integrated. There is no electrical connection relationship between the three phases of the current-type phase-shifting reactor, and there is no leakage current. By adjusting the turn ratio of the phase-shifting reactor, the current of each rectifier bridge arm can be made equal. The magnetic integration core structure is adopted, and the common middle yoke reduces the material loss. The magnetic integration core structure is adopted. When the load increases, the magnetic fields cancel each other out in the common yoke, reducing the magnetic density of the yoke and thus reducing the loss. The integrated design of the filter inductor and the phase-shifting reactor structure reduces the device installation difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 FIG. is the electrical schematic diagram of the current-type twelve-pulse rectifier phase-shifting reactor;

[0033] Figure 2 FIG. is the schematic diagram of the iron core structure of the current-type twelve-pulse rectifier phase-shifting reactor;

[0034] Figure 3 FIG. is the winding relationship diagram of the phase-shifting reactor of the current-type twelve-pulse rectifier phase-shifting reactor;

[0035] Figure 4 FIG. is the schematic diagram of the number of turns of the phase A winding of the current-type twelve-pulse rectifier phase-shifting reactor;

[0036] Figure 5 FIG. is the schematic diagram of the air gap structure of the iron core of the current-type twelve-pulse rectifier phase-shifting reactor;

[0037] Figure 6 FIG. is the schematic diagram of the system principle of the current-type twelve-pulse rectifier phase-shifting reactor;

[0038] Figure 7 FIG. is the schematic diagram of the yoke magnetic flux in the phase-shifting reactor;

[0039] Among them, 10 - current-type twelve-pulse rectifier phase-shifting reactor, 11 - iron core, 20 - twelve-pulse rectifier bridge, 30 - capacitor, 40 - load, 110 - lower yoke, 111 - middle yoke, 112 - upper yoke, 121 - first magnetic column, 122 - second magnetic column, 123 - third magnetic column, 124 - fourth magnetic column, 125 - fifth magnetic column, 126 - sixth magnetic column, 127 - seventh magnetic column, 128 - eighth magnetic column, 131 - first air gap, 132 - second air gap, 133 - third air gap. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0041] Embodiment 1

[0042] This embodiment discloses a current - type twelve - pulse rectifier phase - shifting reactor, which includes an iron core and multiple windings. Please refer to Figure 2 , the iron core includes an upper yoke 112, a middle yoke 111, and a lower yoke 110. The upper yoke 112 and the middle yoke 111, as well as the middle yoke 111 and the lower yoke 110, are respectively connected by magnetic columns. There are five magnetic columns between the middle yoke 111 and the lower yoke 110, which are defined as the first magnetic column 121, the second magnetic column 122, the third magnetic column 123, the fourth magnetic column 124, and the fifth magnetic column 125 from left to right. There are three magnetic columns between the upper yoke 112 and the middle yoke 111, which are defined as the sixth magnetic column 126, the seventh magnetic column 127, and the eighth magnetic column 128 from left to right.

[0043] Please refer to Figure 5 , the sixth magnetic column 126, the seventh magnetic column 127, and the eighth magnetic column 128 are not directly connected to the upper yoke 112, but instead leave air gaps 131, 132, and 133 respectively. The parameters of the filter inductor are adjusted by adjusting the size of the air gaps.

[0044] The middle yoke 111, the lower yoke 110 and the first magnetic column 121, the second magnetic column 122, the third magnetic column 123, the fourth magnetic column 124, the fifth magnetic column 125 adopt a cross - laminated method without leaving air gaps.

[0045] The windings are divided into three phases, with four windings in each phase, for a total of twelve windings. The four windings of phase A are respectively defined as winding A0, winding A1, winding A2, and winding A3; the four windings of phase B are respectively defined as winding B0, winding B1, winding B2, and winding B3; the four windings of phase C are respectively defined as winding C0, winding C1, winding C2, and winding C3. The windings are wound on the magnetic columns. For the connection relationship, please refer to Figure 1 , three windings A1, C2, and C3 are wound on the first magnetic column 121, three windings B1, A2, and A3 are wound on the third magnetic column 123, three windings C1, B2, and B3 are wound on the fifth magnetic column 125, winding A0 is wound on the sixth magnetic column 126, winding B0 is wound on the seventh magnetic column 127, winding C0 is wound on the eighth magnetic column 128, and there are no windings on the second magnetic column 122 and the fourth magnetic column 124. It can be seen from the figure that there is no direct electrical interconnection between the three - phase electricity, but instead, phase - shifting is achieved through magnetic - field coupling to realize twelve - pulse rectification.

[0046] Please refer to Figure 1 and Figure 3 , the windings are connected independently for each phase. One end of winding A0 is connected to one end of winding A1, and the other end of winding A1 is simultaneously connected to winding A2 and winding A3; one end of winding B0 is connected to one end of winding B1, and the other end of winding B1 is simultaneously connected to winding B2 and winding B3; one end of winding C0 is connected to one end of winding C1, and the other end of winding C1 is simultaneously connected to winding C2 and winding C3.

[0047] Embodiment 2

[0048] This embodiment discloses a current - type twelve - pulse rectifier phase - shifting reactor system, which includes the current - type twelve - pulse rectifier phase - shifting reactor 10 and the twelve - pulse rectifier bridge 20 in Embodiment 1. The input of the current - type twelve - pulse rectifier phase - shifting reactor 10 is electrically connected to the three - wire input, and it outputs six groups of currents, which are respectively connected to the mid - points of the six bridge arms of the twelve - pulse rectifier bridge 20. A capacitor 30 is connected in parallel at both ends of the twelve - pulse rectifier bridge 20, and both ends of the capacitor 30 are connected to the load 40. The current - type twelve - pulse rectifier phase - shifting reactor 10 divides the three - wire input electricity into six groups of currents, which are rectified into direct current by the twelve - pulse rectifier bridge 20 to provide direct current for the load 40. Among them, the capacitor 30 can make the direct current more stable and smooth, reducing the ripple.

[0049] Please refer to Figure 6 , the U line of the three - phase electricity is connected to one end of the A0 winding, the other end of the A0 winding is connected to one end of the A1 winding, and the other end of the A1 winding is simultaneously connected to the A2 winding and the A3 winding. The other end of the A2 winding is connected to the mid - point of the fourth bridge arm of the twelve - pulse rectifier bridge, and the other end of the A3 winding is connected to the mid - point of the third bridge arm of the twelve - pulse rectifier bridge;

[0050] The V line of the three - phase electricity is connected to one end of the B0 winding, the other end of the B0 winding is connected to one end of the B1 winding, and the other end of the B1 winding is simultaneously connected to the B2 winding and the B3 winding. The other end of the B2 winding is connected to the mid - point of the sixth bridge arm of the twelve - pulse rectifier bridge, and the other end of the B3 winding is connected to the mid - point of the fifth bridge arm of the twelve - pulse rectifier bridge;

[0051] The W line of the three - phase electricity is connected to one end of the C0 winding, the other end of the C0 winding is connected to one end of the C1 winding, and the other end of the C1 winding is simultaneously connected to the C2 winding and the C3 winding. The other end of the C2 winding is connected to the mid - point of the second bridge arm of the twelve - pulse rectifier bridge, and the other end of the C3 winding is connected to the mid - point of the first bridge arm of the twelve - pulse rectifier bridge;

[0052] The twelve - pulse rectifier bridge has six bridge arms, and the connection point of two series - connected thyristors on each bridge arm is the mid - point of the bridge arm.

[0053] To achieve the purpose of canceling each other out of the high - order harmonic currents in the twelve - pulse rectification, it is necessary to adjust the turn relationship of the phase - shifting reactor so that the current Ia1 and the current Ia2, the current Ib1 and the current Ib2, and the current Ic1 and the current Ic2 differ by 30°. Without considering the influence of other factors, the turn ratio relationship of the phase - shifting reactor is as follows:

[0054]

[0055]

[0056] Among them, are the number of turns of windings A1, B1, and C1, are the number of turns of windings A2, B2, and C2 are the number of turns of windings A3, B3, and C3.

[0057] To better test the performance of the current-type phase-shifting reactor, the number of turns of a 30 kW current-type twelve-pulse rectifier phase-shifting reactor with a magnetic integrated filter inductor is designed:

[0058]

[0059] Among them, are the number of turns of windings A0, B0, and C0.

[0060] After testing, the three-phase power factor can reach 0.98, and the three-phase current ripple contents are 4.5%, 4.3%, and 4.8% respectively.

[0061] Please refer to Figure 7 to analyze the magnetic flux situation of each section of the middle yoke. The middle yoke is divided into 7 sections according to different connection structures. The figure shows the corresponding relationship of the magnetic flux change situation of each section under the action of current phase shift. As the load increases, the magnetic flux generated by windings A0, B0, and C0 also increases, and it is superimposed and partially offset with the magnetic flux under the action of current phase shift on the middle yoke.

[0062] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A current-type twelve-pulse rectifier phase-shifting reactor, characterized in that, It includes an iron core and multiple windings; The iron core includes an upper yoke, a middle yoke and a lower yoke, and the upper yoke and the middle yoke, as well as the middle yoke and the lower yoke, are respectively connected by magnetic columns; The windings are divided into three phases and wound on the magnetic columns. The windings are independently connected according to each phase, so that the phase-shift angle of the output current of each of the two groups is 30°; There are five magnetic columns between the middle yoke and the lower yoke, which are defined as the first magnetic column, the second magnetic column, the third magnetic column, the fourth magnetic column, and the fifth magnetic column from left to right. There are three magnetic columns between the upper yoke and the middle yoke, which are defined as the sixth magnetic column, the seventh magnetic column, and the eighth magnetic column from left to right; Each phase has four windings, and there are a total of twelve windings. The four windings of phase A are respectively defined as winding A0, winding A1, winding A2, and winding A3; the four windings of phase B are respectively defined as winding B0, winding B1, winding B2, and winding B3; the four windings of phase C are respectively defined as winding C0, winding C1, winding C2, and winding C3; Three windings, namely A1, C2, and C3, are wound on the first magnetic column. Three windings, namely B1, A2, and A3, are wound on the third magnetic column. Three windings, namely C1, B2, and B3, are wound on the fifth magnetic column. Winding A0 is wound on the sixth magnetic column. Winding B0 is wound on the seventh magnetic column. Winding C0 is wound on the eighth magnetic column. There are no windings on the second and fourth magnetic columns; The connection relationship of the twelve windings is as follows: One end of winding A0 is connected to one end of winding A1, and the other end of winding A1 is simultaneously connected to winding A2 and winding A3; One end of winding B0 is connected to one end of winding B1, and the other end of winding B1 is simultaneously connected to winding B2 and winding B3; One end of winding C0 is connected to one end of winding C1, and the other end of winding C1 is simultaneously connected to winding C2 and winding C3; An air gap is left between the upper yoke and the magnetic column; The middle yoke and the magnetic column, as well as the lower yoke and the magnetic column, are connected in a cross-laminated manner without leaving an air gap; The winding turn ratio relationship is as follows: Among them, are the number of turns of windings A1, B1, and C1 respectively, are the number of turns of windings A2, B2, and C2 respectively, are the number of turns of windings A3, B3, and C3 respectively.

2. The current-type twelve-pulse rectifier phase-shifting reactor according to claim 1, wherein The winding turn ratio relationship is as follows: Among them, are the number of turns of windings A0, B0, and C0 respectively.

3. A current-type twelve-pulse rectifier phase-shifting reactor system, characterized in that, It includes the current-type twelve-pulse rectifier phase-shifting reactor and the twelve-pulse rectifier bridge as described in claim 1 or 2. The input of the current-type twelve-pulse rectifier phase-shifting reactor is electrically connected to the three-phase input power supply, and six groups of currents are output, which are respectively connected to the midpoints of the six bridge arms of the twelve-pulse rectifier bridge. Capacitors are connected in parallel at both ends of the twelve-pulse rectifier bridge, and both ends of the capacitors are connected to the load.

4. The current-type twelve-pulse rectifier phase-shifting reactor system according to claim 3, wherein: The U line of the three-phase power is connected to one end of winding A0. The other end of winding A0 is connected to one end of winding A1. The other end of winding A1 is simultaneously connected to winding A2 and winding A3. The other end of winding A2 is connected to the midpoint of the fourth bridge arm of the twelve-pulse rectifier bridge. The other end of winding A3 is connected to the midpoint of the third bridge arm of the twelve-pulse rectifier bridge; The V line of the three-phase power is connected to one end of winding B0. The other end of winding B0 is connected to one end of winding B1. The other end of winding B1 is simultaneously connected to winding B2 and winding B3. The other end of winding B2 is connected to the midpoint of the sixth bridge arm of the twelve-pulse rectifier bridge. The other end of winding B3 is connected to the midpoint of the fifth bridge arm of the twelve-pulse rectifier bridge; The W line of the three-phase power supply is connected to one end of the C0 winding, the other end of the C0 winding is connected to one end of the C1 winding, and the other end of the C1 winding is simultaneously connected to the C2 winding and the C3 winding. The other end of the C2 winding is connected to the midpoint of the second bridge arm of the twelve-pulse rectifier bridge, and the other end of the C3 winding is connected to the midpoint of the first bridge arm of the twelve-pulse rectifier bridge; The twelve-pulse rectifier bridge has six bridge arms, and the connection point of two series-connected thyristors on each bridge arm is the midpoint of that bridge arm.

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