Direct current reactor and frequency converter

Abstract

The utility model discloses a direct current reactor and a frequency converter. The direct-current reactor comprises a first iron yoke, a second iron yoke, a magnetic core, a first winding and a second winding, wherein the first iron yoke and the second iron yoke are oppositely arranged; the magnetic core is arranged between the first iron yoke and the second iron yoke and comprises a first side plate, a second side plate and a middle plate, the first side plate and the second side plate are arranged on the two sides of the middle plate respectively, the first side plate, the second side plate and the middle plate are arranged at intervals, at least one end of the first side plate is connected with the first iron yoke or the second iron yoke, and at least one end of the second side plate is connected with the second iron yoke. At least one end of the second side plate is connected with the first yoke or the second yoke, one end of the middle plate is connected with the first yoke, the other end of the middle plate is connected with the second yoke, the width of the first side plate is equal to that of the second side plate, and the width of the middle plate is smaller than that of the first side plate; the first winding is wound on the first side plate; the second winding is wound on the second side plate, and the winding directions of the first winding and the second winding are the same. According to the technical scheme, the structural size can be effectively reduced, and the assembling convenience is improved.

Description

Technical Field

[0001] This invention relates to the field of power technology, specifically to a DC reactor and a frequency converter. Background Technology

[0002] Power systems contain numerous nonlinear electrical devices, such as converters, electric arc furnaces, core equipment, and lighting equipment. These devices distort voltage or current waveforms during operation, resulting in harmonics in the power grid. These harmonics include common-mode harmonics and differential-mode harmonics. The presence of common-mode and differential-mode harmonics can cause relay malfunctions or failures to operate, increase neutral current, reduce grid voltage, increase losses, and shorten transformer lifespan.

[0003] To suppress differential-mode and common-mode harmonics, dual DC reactors are usually installed at the rectifier end of the power supply input. The current suppression method is to install a discrete DC reactor at each of the positive and negative ends of the DC bus. However, discrete DC reactors occupy a large volume of space and are not convenient to assemble. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a DC reactor that can effectively reduce structural volume and improve assembly convenience.

[0005] This application provides a DC reactor, the DC reactor comprising:

[0006] First iron yoke;

[0007] The second iron yoke, wherein the first iron yoke and the second iron yoke are arranged opposite to each other;

[0008] A magnetic core is disposed between a first yoke and a second yoke. The magnetic core includes a first side plate, a second side plate, and a middle plate. The first side plate and the second side plate are disposed on opposite sides of the middle plate and are spaced apart from the middle plate. At least one end of the first side plate is connected to either the first yoke or the second yoke, and at least one end of the second side plate is connected to either the first yoke or the second yoke. One end of the middle plate is connected to the first yoke, and the other end of the middle plate is connected to the second yoke. The widths of the first side plate and the second side plate are equal, and the width of the middle plate is less than the width of the first side plate.

[0009] The first winding is wound on the first side plate. One end of the first winding is connected to a first input cable, and the other end of the first winding is connected to a first output cable.

[0010] The second winding is wound on the second side plate. The first winding and the second winding are wound in the same direction. One end of the second winding is connected to a second inlet cable, and the other end of the second winding is connected to a second outlet cable. The first inlet cable and the second inlet cable are located on the same side of the magnetic core.

[0011] In one aspect, the width of the middle plate is w, and the width of the first side plate is W1, which satisfies: 20% ≤ w / W1 ≤ 80%.

[0012] In one aspect, 20mm≤w≤80mm.

[0013] In one aspect, one end of the first side plate is connected to the first yoke, and the other end of the first side plate is spaced apart from the second yoke to form a first air gap;

[0014] One end of the second side plate is connected to the first iron yoke, and a second air gap is formed between the other end of the second side plate and the second iron yoke.

[0015] In one aspect, the first side plate includes a first connecting segment and a second connecting segment, one end of the first connecting segment is connected to the first yoke, one end of the second connecting segment is connected to the second yoke, and the first connecting segment and the second connecting segment are spaced apart to form a first air gap.

[0016] The second side plate includes a third connecting section and a fourth connecting section. One end of the third connecting section is connected to the first iron yoke, and one end of the fourth connecting section is connected to the second iron yoke. The third connecting section and the fourth connecting section are spaced apart to form a second air gap.

[0017] In one aspect, let the width of the first air gap be d1, the width of the second air gap be d2, the length of the first side plate be L1, and the length of the second side plate be L2, then the following conditions are met:

[0018] 1% ≤ d1 / L1 ≤ 10%;

[0019] 1% ≤ d² / L² ≤ 10%.

[0020] In one aspect, 1mm≤d1≤10mm, 1mm≤d2≤10mm.

[0021] In one aspect, the distance between the first side plate and the middle plate is P1, the distance between the second side plate and the middle plate is P2, the winding length of the first winding is S1, and the winding length of the second winding is S2, then the following conditions are met:

[0022] 1 / 8 ≤ P1 / S1 ≤ 1 / 4;

[0023] 1 / 8 ≤ P2 / S2 ≤ 1 / 4.

[0024] In one aspect, 15mm≤P1≤40mm, 15mm≤P2≤40mm.

[0025] In addition, to solve the above problems, this application also provides a frequency converter, which includes a rectifier main circuit, an inverter circuit and the DC reactor described above. The first input cable and the second input cable of the DC reactor are connected to the rectifier main circuit, and the first output cable and the second output cable are connected to the inverter circuit.

[0026] The beneficial effects of this invention are as follows: the first side plate and the second side plate are separated by a middle plate. The first side plate is used to house the first winding, and the second side plate is used to house the second winding. The first side plate, the first winding, and the middle plate can suppress harmonics, and the second side plate, the second winding, and the middle plate can also suppress harmonics. By spacing the middle plates, the two reactors are integrated together, thereby reducing the structural volume and improving the ease of assembly. Moreover, the width of the middle plate is smaller than the width of the first side plate, further reducing the structural volume and facilitating assembly. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0028] Figure 1 This is a schematic diagram of the DC reactor in this application;

[0029] Figure 2 For this application Figure 1 A schematic diagram of an embodiment of the magnetic core in a DC reactor;

[0030] Figure 3 For this application Figure 1 A schematic diagram of another embodiment of the magnetic core in a DC reactor;

[0031] Figure 4 This is a schematic diagram illustrating the reduction of differential-mode harmonics in the DC reactor of this application;

[0032] Figure 5 This is a schematic diagram illustrating the reduction of common-mode harmonics in the DC reactor of this application.

[0033] Reference numerals: 100, first yoke; 200, second yoke; 300, magnetic core; 400, first winding; 500, second winding; 600, rectifier main circuit; 700, inverter circuit; 800, support frame;

[0034] 310, First side plate; 320, Second side plate; 330, Middle plate; 301, First air gap; 302, Second air gap; 311, First connecting section; 312, Second connecting section; 321, Third connecting section; 322, Fourth connecting section; 410, First inlet cable; 420, First outlet cable; 430, Second inlet cable; 440, Second outlet cable. Detailed Implementation

[0035] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0036] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0037] This application provides a DC reactor, comprising: a first yoke 100, a second yoke 200, a magnetic core 300, a first winding 400, and a second winding 500. The yoke is typically made of silicon steel sheets or other highly permeable magnetic materials, possessing sufficient mechanical strength to support the weight of the coils. The magnetic core 300 refers to a sintered magnetic metal oxide composed of various iron oxide mixtures. For example, manganese-zinc ferrite and nickel-zinc ferrite are typical materials for the magnetic core 300. Manganese-zinc ferrite features high permeability and high flux density, and low loss. Nickel-zinc ferrite has extremely high impedance and low permeability (less than several hundred). Ferrite magnetic core 300, etc.

[0038] The first yoke 100 and the second yoke 200 are arranged opposite to each other; the first yoke 100 and the second yoke 200 are spaced a certain distance apart, and usually the first yoke 100 and the second yoke 200 are arranged in parallel.

[0039] A magnetic core 300 is disposed between a first yoke 100 and a second yoke 200. The magnetic core 300 includes a first side plate 310, a second side plate 320, and a middle plate 330. The first side plate 310 and the second side plate 320 are disposed on both sides of the middle plate 330 and are spaced apart from the middle plate 330. At least one end of the first side plate 310 is connected to either the first yoke 100 or the second yoke 200. That is, one end of the first side plate 310 is connected to the first yoke 100 and the other end is spaced apart from the second yoke 200, or one end of the first side plate 310 is connected to the second yoke 200 and the other end is spaced apart from the first yoke 100, or both ends of the first side plate 310 are connected to the first yoke 100 and the second yoke 200. At least one end of the second side plate 320 is connected to either the first yoke 100 or the second yoke 200. Similarly, it can be understood that one end of the second side plate 320 is connected to the first yoke 100, and the other end is spaced apart from the second yoke 200; or one end of the second side plate 320 is connected to the second yoke 200, and the other end is spaced apart from the first yoke 100; or, both ends of the second side plate 320 are connected to both the first yoke 100 and the second yoke 200. One end of the middle plate 330 is connected to the first yoke 100, and the other end of the middle plate 330 is connected to the second yoke 200, thus separating the first side plate 310 and the second side plate 320. The widths of the first side plate 310 and the second side plate 320 are equal, while the width of the middle plate 330 is less than the width of the first side plate 310; by reducing the width of the middle plate 330, the structural volume is reduced.

[0040] The first winding 400 is wound on the first side plate 310. One end of the first winding 400 is connected to the first input cable 410, and the other end of the first winding 400 is connected to the first output cable 420. The first input cable 410 is used for current to flow into the connection port, and the first output cable 420 is used for current to flow out.

[0041] The second winding 500 is wound on the second side plate 320. The first winding 400 and the second winding 500 are wound in the same direction. One end of the second winding 500 is connected to the second input cable 430, and the other end of the second winding 500 is connected to the second output cable 440. The first input cable 410 and the second input cable 430 are located on the same side of the magnetic core 300. The second input cable 430 is used for current inflow connection, and the second output cable 440 is used for current outflow.

[0042] In this embodiment of the DC reactor, the first side plate 310 and the second side plate 320 are separated by a middle plate 330. The first side plate 310 is used to house the first winding 400, and the second side plate 320 is used to house the second winding 500. The first side plate 310, the first winding 400, and the middle plate 330 can suppress harmonics, as can the second side plate 320, the second winding 500, and the middle plate 330. By spacing the middle plates 330, the two reactors are integrated together, thereby reducing the structural volume and improving the ease of assembly. Moreover, the width of the middle plate 330 is smaller than the width of the first side plate 310, further reducing the structural volume and facilitating assembly.

[0043] Additionally, it should be noted that the first yoke 100 and the second yoke 200 in this application can both be plate-shaped structures. As can be seen from the structures of the first side plate 310, the second side plate 320, and the middle plate 330, the magnetic core 300 is also a plate-shaped structure. It is understandable that the DC reactor in this application is primarily a flat structure, with a thinner overall structure, which is beneficial for installation in frequency converters.

[0044] The DC reactor also includes a bracket 800, which is mounted on the first yoke 100 and the second yoke 200 for fixed connection of the DC reactor.

[0045] In one embodiment of this application, the width of the middle plate 330 is w, and the width of the first side plate 310 is W1, which satisfies: 20% ≤ w / W1 ≤ 80%. Therefore, the width of the middle plate 330 is relatively narrow; for example, the width of the middle plate 330 can be 20%, 30%, 40%, 50%, 60%, 70%, or 80% of the width of the first side plate 310. The width of the second side plate 320 is W2, and W1 equals W2.

[0046] Furthermore, 20mm ≤ w ≤ 80mm. The width of the middle plate 330 can be 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, or 80mm. The width of the middle plate 330 can be adjusted according to the structural space. Generally, the larger the current connected, the wider the width of the middle plate 330 should be, provided that the first side plate 310 and the second side plate 320 are effectively separated.

[0047] like Figure 2As shown, in one embodiment of this application, one end of the first side plate 310 is connected to the first yoke 100, and the other end of the first side plate 310 and the second yoke 200 form a first air gap 301; one end of the second side plate 320 is connected to the first yoke 100, and the other end of the second side plate 320 and the second yoke 200 form a second air gap 302. The air in the air gap of the magnetic core 300 significantly impedes the magnetic field, causing the magnetic flux to be hindered at the air gap, thereby reducing the permeability. The introduction of the air gap makes the magnetic domain arrangement of the magnetic core 300 less ordered, requiring a larger current to saturate the magnetic core 300. When a magnetic field is established in the magnetic core 300, the magnetic domains will arrange themselves in an ordered state, thereby storing energy. Due to the presence of the air gap, the ordered arrangement of the magnetic domains is broken, allowing the magnetic core 300 to store more energy. The introduction of the air gap can disrupt the ordered arrangement of the magnetic domains, thereby reducing remanence. Of course, the first air gap 301 and the second air gap 302 can also be set at one end near the first iron yoke 100.

[0048] like Figure 3 As shown in one embodiment of this application, the first side plate 310 includes a first connecting segment 311 and a second connecting segment 312. One end of the first connecting segment 311 is connected to the first yoke 100, and one end of the second connecting segment 312 is connected to the second yoke 200. The first connecting segment 311 and the second connecting segment 312 are spaced apart to form a first air gap 301. The second side plate 320 includes a third connecting segment 321 and a fourth connecting segment 322. One end of the third connecting segment 321 is connected to the first yoke 100, and one end of the fourth connecting segment 322 is connected to the second yoke 200. The third connecting segment 321 and the fourth connecting segment 322 are spaced apart to form a second air gap 302. The first air gap 301 can be located in the middle of the first side plate 310, and the second air gap 302 can also be located in the middle of the second side plate 320.

[0049] In one embodiment of this application, the width of the first air gap 301 is defined as d1, the width of the second air gap 302 as d2, the length of the first side plate 310 as L1, and the length of the second side plate 320 as L2, then satisfying: 1% ≤ d1 / L1 ≤ 10%, 1% ≤ d2 / L2 ≤ 10%. The widths of the first air gap 301 and the second air gap 302 can also be adjusted as needed. The ratio of the width of the first air gap 301 to the length of the first side plate 310 can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. The ratio of the width of the second air gap 302 to the length of the second side plate 320 can also be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0050] Furthermore, 1mm ≤ d1 ≤ 10mm, 1mm ≤ d2 ≤ 10mm. The width of the first air gap 301 can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm. The width of the second air gap 302 can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm.

[0051] In one embodiment of this application, the distance between the first side plate 310 and the middle plate 330 is P1, the distance between the second side plate 320 and the middle plate 330 is P2, the winding length of the first winding 400 is S1, and the winding length of the second winding 500 is S2. Then, the following conditions are met: 1 / 8 ≤ P1 / S1 ≤ 1 / 4, 1 / 8 ≤ P2 / S2 ≤ 1 / 4. The distance between the first side plate 310 and the middle plate 330 is sufficient to accommodate the first winding 400. Similarly, the distance between the second side plate 320 and the middle plate 330 is sufficient to accommodate the second winding 500. The ratio of P1 to S1 can be 1 / 8, 1 / 7, 1 / 6, 1 / 5, or 1 / 4, and the ratio of P2 to S2 can also be 1 / 8, 1 / 7, 1 / 6, 1 / 5, or 1 / 4. P1 can be equal to P2.

[0052] Furthermore, 15mm ≤ P1 ≤ 40mm, 15mm ≤ P2 ≤ 40mm. P1 can be 15mm, 20mm, 25mm, 30mm, 35mm, or 40mm. P2 can also be 15mm, 20mm, 25mm, 30mm, 35mm, or 40mm.

[0053] This application also provides a frequency converter, which includes a rectifier main circuit 600, an inverter circuit 700, and the aforementioned DC reactor. The first input cable 410 and the second input cable 430 of the DC reactor are connected to the rectifier main circuit 600, and the first output cable 420 and the second output cable 440 are connected to the inverter circuit 700. The DC reactor reduces harmonics passing through the rectifier main circuit 600. The solution of this application can reduce common-mode harmonics when they are generated, and it can also reduce differential-mode harmonics when they are generated.

[0054] The rectifier main circuit 600 is used to convert three-phase AC power into single-phase DC power. Corresponding to the rectifier circuit 600, the inverter circuit 700 converts DC power into AC power.

[0055] like Figure 4As shown, it can be seen that in the flow path of the output magnetic integrated dual DC reactor of the rectifier main circuit 600, the first winding 400 and the second winding 500 have the same winding direction. At this time, the differential mode magnetic flux flows in the closed magnetic circuit formed by the first side plate 310 and the middle plate 330, and the second side plate 320 and the middle plate 330, respectively, forming differential mode inductance Q1 and differential mode inductance Q2, while the differential mode magnetic flux cancels each other out on the middle plate 330.

[0056] like Figure 5 As shown, the common-mode current signal in the dual DC reactor integrated at the output of the rectifier main circuit 600 flows through the a`-b` and c`-d` paths. The first winding 400 and the second winding 500 have the same winding direction. At this time, the common-mode magnetic flux flows in the closed magnetic circuit formed by the two side plates 6 and the middle plate 330, forming common-mode inductors Q1` and Q2`, and the common-mode inductors also cancel each other out.

[0057] In this embodiment of the frequency converter, the first side plate 310 and the second side plate 320 are separated by a middle plate 330. The first side plate 310 is used to house the first winding 400, and the second side plate 320 is used to house the second winding 500. The first side plate 310, the first winding 400, and the middle plate 330 can suppress harmonics, as can the second side plate 320, the second winding 500, and the middle plate 330. The spacing of the middle plates 330 is equivalent to integrating two reactors together, thereby reducing the structural volume and improving the ease of assembly. Moreover, the width of the middle plate 330 is smaller than the width of the first side plate 310, further reducing the structural volume and facilitating assembly. Furthermore, since the first yoke 100 and the second yoke 200 in this application are both plate-shaped structures, and considering the structures of the first side plate 310, the second side plate 320, and the middle plate 330, the magnetic core 300 is also a plate-shaped structure. The DC reactor in this application is mainly of a flat structure, which is thinner overall and facilitates installation in frequency converters.

[0058] The specific embodiments and beneficial effects of the chip in this application are described in the above-mentioned DC reactor, and will not be repeated here.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A DC reactor, characterized in that, The DC reactor includes: First iron yoke; The second iron yoke, wherein the first iron yoke and the second iron yoke are arranged opposite to each other; A magnetic core is disposed between a first yoke and a second yoke. The magnetic core includes a first side plate, a second side plate, and a middle plate. The first side plate and the second side plate are disposed on opposite sides of the middle plate and are spaced apart from the middle plate. At least one end of the first side plate is connected to either the first yoke or the second yoke, and at least one end of the second side plate is connected to either the first yoke or the second yoke. One end of the middle plate is connected to the first yoke, and the other end of the middle plate is connected to the second yoke. The widths of the first side plate and the second side plate are equal, and the width of the middle plate is less than the width of the first side plate. The first winding is wound on the first side plate. One end of the first winding is connected to a first input cable, and the other end of the first winding is connected to a first output cable. The second winding is wound on the second side plate. The first winding and the second winding are wound in the same direction. One end of the second winding is connected to a second inlet cable, and the other end of the second winding is connected to a second outlet cable. The first inlet cable and the second inlet cable are located on the same side of the magnetic core.

2. The DC reactor according to claim 1, characterized in that, The width of the middle plate is w, and the width of the first side plate is W1, which satisfies: 20% ≤ w / W1 ≤ 80%.

3. The DC reactor according to claim 2, characterized in that, 20mm≤w≤80mm.

4. The DC reactor according to claim 1, characterized in that, One end of the first side plate is connected to the first iron yoke, and the other end of the first side plate and the second iron yoke are spaced apart to form a first air gap; One end of the second side plate is connected to the first iron yoke, and a second air gap is formed between the other end of the second side plate and the second iron yoke.

5. The DC reactor according to claim 1, characterized in that, The first side plate includes a first connecting segment and a second connecting segment. One end of the first connecting segment is connected to the first yoke, and one end of the second connecting segment is connected to the second yoke. The first connecting segment and the second connecting segment are spaced apart to form a first air gap. The second side plate includes a third connecting section and a fourth connecting section. One end of the third connecting section is connected to the first iron yoke, and one end of the fourth connecting section is connected to the second iron yoke. The third connecting section and the fourth connecting section are spaced apart to form a second air gap.

6. The DC reactor according to claim 4 or 5, characterized in that, Let the width of the first air gap be d1, the width of the second air gap be d2, the length of the first side plate be L1, and the length of the second side plate be L2. Then, the following conditions are met: 1% ≤ d1 / L1 ≤ 10%; 1% ≤ d² / L² ≤ 10%.

7. The DC reactor according to claim 6, characterized in that, 1mm≤d1≤10mm, 1mm≤d2≤10mm.

8. The DC reactor according to claim 1, characterized in that, The distance between the first side plate and the middle plate is P1, the distance between the second side plate and the middle plate is P2, the winding length of the first winding is S1, and the winding length of the second winding is S2. Then, the following conditions are met: 1 / 8 ≤ P1 / S1 ≤ 1 / 4; 1 / 8 ≤ P2 / S2 ≤ 1 / 4.

9. The DC reactor according to claim 8, characterized in that, 15mm≤P1≤40mm, 15mm≤P2≤40mm.

10. A frequency converter, characterized in that, The frequency converter includes a rectifier main circuit, an inverter circuit, and a DC reactor as described in any one of claims 1 to 9. The first input cable and the second input cable of the DC reactor are connected to the rectifier main circuit, and the first output cable and the second output cable are connected to the inverter circuit.

Images