A coil of electromagnetic repulsion mechanism based on slotted yoke

Abstract

The present invention belongs to the field of fast mechanical switch operating mechanism, and discloses an electromagnetic repulsion mechanism coil based on a slotted yoke, comprising: a coil frame, a baffle, a fastener, a winding coil and a yoke; the yoke is a radially slotted separate structure, a coil frame is arranged at the center of the yoke, the outside of the yoke is surrounded by fasteners and fixed together on the baffle, and a winding coil is arranged inside the yoke; the flow path of the induced eddy current in the yoke is increased by radial grooving, and the eddy currents in the yokes on both sides of the slots are in opposite directions, which offsets the demagnetization effect of the eddy current, reduces spatial magnetic leakage, improves energy conversion efficiency, and improves driving efficiency. The electromagnetic repulsion mechanism coil provided by the present invention can effectively reduce the eddy current loss and magnetic saturation effect of the yoke itself, help reduce spatial magnetic leakage, and improve the driving efficiency of the electromagnetic repulsion mechanism.

Description

Technical Field

[0001] The present invention belongs to the field of fast mechanical switch operating mechanisms, and more specifically, relates to an electromagnetic repulsion mechanism coil based on a slotted magnetic yoke. Background Art

[0002] The development of a circuit breaker that can quickly cut off fault current is the key to promoting the development and application of high-voltage DC power grid technology. According to different topological principles, DC circuit breakers can be divided into three types: mechanical DC circuit breakers, solid-state DC circuit breakers, and hybrid DC circuit breakers. Solid-state DC circuit breakers require a large number of power electronic devices in series and parallel, resulting in high current loss. Currently, the solutions suitable for high-voltage DC power grids are mainly mechanical and hybrid.

[0003] The fast mechanical switch is the key component of the two, and its action speed determines the breaking performance of the DC circuit breaker. The traditional operating mechanism is not suitable for the above occasions because of its large number of action links and large cumulative motion tolerance, which makes its response time dispersion large and the opening and closing time long. Compared with the traditional operating mechanism, the electromagnetic repulsion mechanism has the advantages of short response time, fast opening speed and simple structure, and is widely used in the field of fast mechanical switches.

[0004] Currently, most electromagnetic repulsion mechanisms are hollow coil structures, and most of the magnetic field energy is consumed in the air, resulting in a very low utilization rate of the main magnetic flux. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of the present invention is to provide an electromagnetic repulsion mechanism coil based on a slotted magnetic yoke, aiming to solve the problem that the electromagnetic repulsion mechanism in the prior art adopts a hollow coil structure, so that most of the magnetic field energy is consumed in the air, and the magnetic flux utilization rate is low, resulting in low driving efficiency.

[0006] The present invention provides an electromagnetic repulsion mechanism coil based on a slotted yoke, comprising a coil frame, a baffle, a fastener, a winding coil and a yoke; the yoke is a radially slotted separate structure, a coil frame is arranged at the center of the yoke, the outside of the yoke is surrounded by fasteners and fixed on the baffle, and a winding coil is arranged inside the yoke; the flow path of the induced eddy current in the yoke is increased by radial grooving, and the eddy currents in the yoke on both sides of the slot are in opposite directions, which offsets the demagnetization effect of the eddy current, reduces spatial magnetic leakage, improves energy conversion efficiency, and enhances driving efficiency.

[0007] Further preferably, the yoke may be cylindrical, and the number of slots in the yoke is greater than or equal to 4.

[0008] In the present invention, the yoke is cylindrical, with radial grooves on the surface, a coil frame is arranged in the center, and the outside is surrounded by fasteners and fixed together on the baffle. A winding coil is arranged inside the yoke, and an integrated structure is cast by epoxy resin. The eddy current loss and magnetic saturation effect of the yoke itself can be effectively reduced, which helps to reduce spatial magnetic leakage and improve the driving efficiency of the electromagnetic repulsion mechanism.

[0009] Further preferably, the material of the magnetic yoke can be electrical pure iron DT-4. DT-4 has high magnetic permeability, which can effectively constrain the magnetic field around the coil, prevent the magnetic field from spreading outward, and concentrate the magnetic lines of force around the coil and the energy conversion element to improve the electromagnetic coupling between the two, thereby obtaining a higher electromagnetic driving force under the same driving current.

[0010] Further preferably, the yoke and the coil are cast into an integrated structure by epoxy resin, thereby removing redundant fixings on the surface of the coil and reducing the initial gap between the coil and the energy conversion element, thereby increasing the electromagnetic coupling degree of the mechanism in the initial stage of movement and increasing the firmness of the coil.

[0011] Further preferably, the coil frame and the baffle are both provided with through holes in their centers, and the two are connected by threads.

[0012] Further preferably, the yoke and the fastener are fixed to the baffle by bolts or rivets. Since the yoke is a separate structure, fixing the yoke on the baffle facilitates the assembly and casting of the two; the fastener is equivalent to increasing the contact area of ​​the yoke during casting, making the coil structure more secure.

[0013] Further preferably, the coil skeleton can be cylindrical, and the material of the coil skeleton is epoxy glass cloth. Glass cloth is a fabric woven from epoxy glass fiber; it has the properties of insulation, heat insulation, corrosion resistance, non-combustion, high temperature resistance, high strength, etc., and is mainly used as an insulation material and a reinforcing material for glass fiber reinforced plastics.

[0014] Further preferably, the fastener may be cylindrical, and the material of the fastener is epoxy glass cloth.

[0015] Further preferably, the baffle may be an epoxy glass cloth board.

[0016] Compared with the prior art, the above technical solutions conceived by the present invention have the following technical effects:

[0017] (1) Since the magnetic yoke in the present invention is a radially slotted separate structure, compared with the prior art, the present invention can ensure that the magnetic field enters the coil closed loop according to a more ideal channel within the use area, thereby greatly improving the energy conversion efficiency of the magnetic field, so that the repulsion mechanism can obtain a greater electromagnetic driving force under the same driving parameters, thereby improving the driving efficiency of the electromagnetic repulsion mechanism and reducing the capacity and cost of the power supply.

[0018] (2) In the present invention, the more slots there are in the yoke, the smaller the eddy current induced in the yoke when the mechanism is operated, and the more significant the magnetization effect of the yoke.

[0019] (3) The present invention sets the yoke to be cylindrical, which is convenient for fixing and holding the winding coil. The yoke and the coil are cast into an integrated structure. The winding coil and the yoke are fixed by epoxy resin casting, and the redundant fixing parts on the surface of the coil are removed. In this way, the initial gap between the coil and the energy conversion element can be as small as possible, increasing the maximum output stroke and driving force of the electromagnetic repulsion mechanism, and at the same time greatly improving the firmness of the coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a coil of an electromagnetic repulsion mechanism based on a slotted yoke provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of a yoke structure with four slots provided in an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of a yoke structure with 6 slots provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of a yoke structure with 8 slots provided in an embodiment of the present invention.

[0024] The reference numerals of the figures are: 1 - coil frame, 2 - baffle, 3 - fastener, 4 - winding coil, 5 - yoke, 6 - epoxy resin. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0026] The present invention provides an electromagnetic repulsion mechanism coil based on a slotted magnetic yoke. Compared with an air-core coil, the structure effectively reduces spatial magnetic leakage by improving the magnetic circuit, thereby improving the driving efficiency of the repulsion mechanism. At the same time, the present invention is a new coil structure that can reduce spatial magnetic leakage and make full use of magnetic field energy to improve the driving efficiency of the repulsion mechanism, thereby reducing costs and improving the competitiveness of the product.

[0027] Figure 1 FIG. 1 shows a schematic diagram of a coil of an electromagnetic repulsion mechanism based on a slotted yoke provided in an embodiment of the present invention. Figure 2 , Figure 3 , Figure 4 A schematic diagram of a yoke structure with different numbers of slots provided in an embodiment of the present invention is shown. For ease of description, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0028] The present invention provides an electromagnetic repulsion mechanism coil based on a slotted yoke, comprising a coil frame 1, a baffle 2, a fastener 3, a coil 4 and a yoke 5; the yoke 5 is a radially slotted separate structure, the coil frame 1 is arranged at the center of the yoke 5, the outside is surrounded by the fastener 3 and fixed on the baffle 2, and the coil 4 is arranged inside the yoke 5.

[0029] Finite element simulation shows that due to the principle of electromagnetic induction, the changing magnetic field generated by the coil will induce eddy currents in the yoke. If the yoke is an integrated structure, the total magnetic field strength is weakened because the excitation current is opposite to the eddy current direction. At the same time, the eddy current concentrates the magnetic lines of force between the yoke and the coil, and the magnetic conductive material is very easy to reach magnetic saturation, further weakening the effect of the yoke magnetization. In summary, when a non-slotted yoke is added around the coil of the electromagnetic repulsion mechanism, the driving efficiency of the mechanism decreases significantly. In order to increase the flow path of the eddy current and weaken the influence of the eddy current on the magnetic field, the present invention performs radial slots on the yoke and divides it into several fan-shaped parts. The radial slotting increases the flow path of the induced eddy current in the yoke, and at the same time, the eddy currents in the yokes on both sides of the slot are in opposite directions, which offsets the demagnetization effect of the eddy current. The simulation results show that the eddy current demagnetization effect of the slotted yoke is significantly weakened, the magnetic density is evenly distributed in the yoke, the spatial magnetic leakage is effectively reduced, the magnetic field is concentrated around the coil, and the energy conversion efficiency is greatly improved, so that the repulsion mechanism can obtain a higher gate opening speed under the same driving parameters, effectively improving the driving efficiency.

[0030] In the embodiment of the present invention, the yoke 5, the coil frame 1 and the fastener 3 are all cylindrical yokes made of electrical pure iron DT-4. DT-4 has high magnetic permeability and can effectively constrain the magnetic field around the coil to prevent the magnetic field from spreading outward, so that the magnetic lines of force are concentrated around the coil and the energy conversion element to improve the electromagnetic coupling between the two, thereby obtaining a higher electromagnetic driving force under the same driving current.

[0031] The yoke and the coil are cast into an integrated structure through epoxy resin, which removes unnecessary fixings on the surface of the coil and reduces the initial gap between the coil and the energy conversion element, thereby increasing the degree of electromagnetic coupling of the mechanism in the initial stage of movement and increasing the firmness of the coil.

[0032] The yoke and fasteners are fixed to the baffle by bolts or rivets. Since the yoke is a separate structure, fixing the yoke on the baffle facilitates the assembly and casting of the two; the fasteners are equivalent to increasing the contact area of ​​the yoke during casting, making the coil structure more secure.

[0033] The coil frame and the baffle are both provided with through holes in the center, and the two are connected by threads, so that the winding coil and the slotted yoke are easy to assemble and cast. The material of the coil frame can be epoxy glass cloth tube, and the material of the baffle and fasteners is epoxy glass cloth board. Epoxy glass is a non-magnetic material, and will not induce eddy current and consume energy when the mechanism is opened and closed, and it has excellent insulation performance.

[0034] Through the optimization of the above structure, the present invention greatly reduces the scattering of the magnetic field compared with the traditional hollow coil structure, so that most of the magnetic field generated by the coil is conducted through the yoke, and through the extended structure of the yoke, it is ensured that the magnetic field enters the coil closed loop according to a more ideal channel in the use area, so that the energy conversion efficiency of the magnetic field is greatly improved, so that the repulsion mechanism can obtain a greater electromagnetic driving force under the same driving parameters, improve the driving efficiency of the electromagnetic repulsion mechanism, and reduce the capacity and cost of the power supply; the slotted structure of the yoke reduces the eddy current demagnetization effect of the yoke under the changing magnetic field, and further improves the utilization rate of the magnetic field. The more slots in the yoke, the smaller the eddy current induced in the yoke when the mechanism is operated, and the more significant the magnetization effect of the yoke, but the higher the difficulty of processing and assembly. It can be seen from the simulation results that when the number of slots in the yoke reaches 4, the effect of eddy current demagnetization is equivalent to that of yoke magnetization. Therefore, in actual design, it is necessary to consider both processing cost and driving effect to reasonably select the number of slots. Figure 2 , Figure 3 , Figure 4 The typical structures of the yoke when the number of slots is 4, 6, and 8 are given respectively; in addition, the yoke is set to a cylindrical shape to facilitate the fixation and accommodation of the winding coil, the yoke and the coil are cast into an integrated structure, and the winding coil and the yoke are fixed by epoxy resin casting, and the redundant fixings on the surface of the coil are removed, so that the initial gap between the coil and the energy conversion element can be as small as possible, the maximum output stroke and driving force of the electromagnetic repulsion mechanism are increased, and the firmness of the coil is greatly improved.

[0035] In order to further illustrate the electromagnetic repulsion mechanism coil based on the slotted yoke provided by the embodiment of the present invention, the following is a detailed description with reference to the accompanying drawings and in combination with specific embodiments:

[0036] The electromagnetic repulsion mechanism coil based on the slotted yoke provided by the present invention includes: a coil frame 1, a baffle 2, a fastener 3, a winding coil 4 and a yoke 5; the yoke 5, the coil frame 1 and the fastener 3 are all cylindrical, the yoke 5 is provided with the coil frame 1 at the center, the outside is surrounded by the fastener 3 and fixed together on the baffle 2, and the winding coil 4 is provided inside the yoke 5; the yoke 5 is a radially slotted separate structure, the more slots there are, the smaller the induced eddy current in the yoke, but the higher the processing cost and assembly difficulty. It can be seen from the simulation results that when the number of slots in the yoke reaches 4, the effect of eddy current demagnetization and yoke magnetization is equivalent. In this example, the number of slots is 8; the material of the yoke 5 is electrical pure iron DT-4. The DT-4 grade electrical pure iron has a high magnetic permeability, which can effectively constrain the magnetic field around the coil, prevent the magnetic field from spreading outward, and concentrate the magnetic lines of force around the coil and the energy conversion component to improve the degree of electromagnetic coupling between the two, thereby obtaining a higher electromagnetic driving force under the same driving current. The yoke 5 and the winding coil 4 are cast into an integrated structure by epoxy resin, and the redundant fixings on the surface of the coil are removed, and the initial gap between the coil and the energy conversion element is reduced, thereby increasing the electromagnetic coupling degree of the mechanism in the initial stage of movement, and on the other hand, increasing the firmness of the winding coil; the coil frame 1 and the baffle 2 are both provided with through holes in the center, and the two are connected by threads, so that the winding coil and the slotted yoke are convenient to assemble and cast; the yoke 5 and the fastener 1 are fixed to the baffle 2 by bolts or rivets. Since the yoke is a separate structure, fixing the yoke on the baffle facilitates the assembly and casting of the two; the fastener is equivalent to increasing the contact area of ​​the yoke during casting, making the coil structure more secure, and bolts are used for fixing in this example; the material of the coil frame 1 is epoxy glass cloth tube, and the material of the baffle 2 and the fastener 1 is epoxy glass cloth board. Epoxy glass is a non-magnetic material, and will not induce eddy currents and consume energy when the mechanism is opened and closed, and has excellent insulation performance.

[0037] Through the optimization of the above structure, compared with the general hollow coil structure, the scattering of the magnetic field is greatly reduced, so that most of the magnetic field generated by the coil is conducted through the yoke, and through the extended structure of the yoke, it is ensured that the magnetic field enters the coil closed loop according to the ideal channel in the use area, so that the energy conversion efficiency of the magnetic field is greatly improved: the slotted structure of the yoke reduces the eddy current demagnetization effect of the yoke under the changing magnetic field, and further improves the utilization rate of the magnetic field; the winding coil and the yoke are fixed by epoxy resin casting, and the redundant fixings on the surface of the coil are removed, so that the initial gap between the coil and the energy conversion part can be as small as possible, which can increase the maximum output stroke and driving force of the electromagnetic repulsion mechanism. Compared with the hollow coil structure, it can be seen from the finite element simulation results in the literature that the peak value of the electromagnetic force will be increased by about 14% under the same discharge parameters.

[0038] The working process of the electromagnetic repulsion mechanism coil based on the slotted yoke provided by the embodiment of the present invention is now described in detail with reference to the accompanying drawings as follows:

[0039] When the electromagnetic repulsion mechanism performs opening and closing operations, the external power supply discharges to the coil 4, and the discharge current generates a rapidly changing magnetic field in space. The magnetic field is conducted through the magnetic yoke 5 to form a closed magnetic circuit, and an electromagnetic force is generated between the energy conversion element, and the driving mechanism performs opening and closing operations.

[0040] Among them, a high driving efficiency coil structure can be used for the winding coil 4. Two coil shape ratio parameters are defined to describe the coil size: α is the ratio coefficient of the coil height to the average diameter of the coil, and β is the ratio coefficient of the coil radial thickness to the average diameter of the coil. Through simulation and theoretical research, it can be known that the smaller α and the larger β are, the higher the driving efficiency of the electromagnetic repulsion mechanism. In the example of the present invention, the coil specifications with the α coefficient as small as possible and the β coefficient as large as possible under the processing conditions are selected.

[0041] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An electromagnetic repulsion mechanism coil based on a slotted yoke, characterized in that: It comprises a coil frame (1), a baffle (2), a fastener (3), a winding coil (4) and a magnetic yoke (5); The magnetic yoke (5) is a radially slotted separate structure, the coil frame (1) is arranged at the center of the magnetic yoke (5), the outside of the magnetic yoke (5) is surrounded by the fastener (3) and fixed together on the baffle (2), and the winding coil (4) is arranged inside the magnetic yoke (5); the magnetic yoke (5) is cylindrical, and the number of slots of the magnetic yoke (5) is greater than or equal to 4; By radially cutting grooves, the flow path of the induced eddy current in the yoke is increased. The directions of the eddy currents in the yoke on both sides of the grooves are opposite, which offsets the demagnetizing effect of the eddy currents, reduces spatial magnetic leakage, improves energy conversion efficiency, and enhances driving efficiency.

2. The electromagnetic repulsion mechanism coil according to claim 1, characterized in that: The material of the magnetic yoke (5) is electrical pure iron DT-4.

3. The electromagnetic repulsion mechanism coil according to claim 1, characterized in that: The magnetic yoke (5) and the winding coil (4) are cast into an integrated structure by epoxy resin.

4. The electromagnetic repulsion mechanism coil according to claim 1, characterized in that: The coil frame (1) and the baffle (2) are both provided with through holes at their centers, and the two are connected via threads.

5. The electromagnetic repulsion mechanism coil according to claim 1, characterized in that: The yoke (5) and the fastener (3) are fixed to the baffle (2) by means of bolts or rivets.

6. The electromagnetic repulsion mechanism coil according to claim 1, characterized in that: The coil frame (1) is cylindrical, and the material of the coil frame (1) is epoxy glass cloth.

7. The electromagnetic repulsion mechanism coil according to claim 1, characterized in that: The fastener (3) is cylindrical and is made of epoxy glass cloth.

8. The electromagnetic repulsion mechanism coil according to claim 1, characterized in that: The baffle (2) is an epoxy glass cloth plate.

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