Virtual magnetic core constructed using the principle of vector magnetic circuit and its application method

Abstract

The present invention is a virtual magnetic core constructed using the principle of vector magnetic circuit and its application method. By utilizing the principle of vector magnetic circuit, a virtual magnetic core and its application method are proposed, belonging to the field of application of magnetic circuit theory, and particularly relating to the magnetic circuit design of electromagnetic devices. The magnetic core (iron core) is an important component of electromagnetic devices such as motors, transformers, and reactors, accounting for approximately 50% of the total weight of electromagnetic devices. In electromagnetic devices such as air-core transformers, the magnetic core (iron core) is removed, but the air has poor magnetic conductivity and a large exciting current, resulting in weak load-carrying capacity, large volume, and limited application range of electromagnetic devices. The present invention constructs a virtual magnetic circuit using multiple vector magnetic circuit elements, whose magnetic conductivity is similar to or better than that of an actual magnetic core, forming a virtual magnetic core. And based on this, an application method is proposed to construct electromagnetic devices such as transformers, reactors, and motors using the virtual magnetic core, which is expected to significantly reduce the weight and volume of electromagnetic devices.

Description

Technical Field

[0001] The present invention belongs to the field of application of magnetic circuit theory, and particularly relates to the magnetic circuit design of electromagnetic devices. Background Art

[0002] As the carrier of the magnetic circuit, the magnetic core (iron core) provides a clear and predictable path for magnetic flux, and effectively concentrates and guides magnetic field energy. It is an indispensable and important component of electromagnetic devices such as transformers, reactors, and motors, and has a wide range of applications. For the convenience of description, the present invention uniformly uses the term "magnetic core" for description. According to "High-frequency magnetic components" (second edition) written by Kazimierczuk M.K., there are mainly two ways to form the current magnetic core.

[0003] The first is the traditional magnetic core, which is made of high-permeability materials (such as metal parts, powder materials, ferrites, etc.) and can form a complete closed magnetic circuit. This magnetic core has a high magnetic permeability, can effectively confine magnetic flux, reduce magnetic leakage, thus significantly reducing magnetic circuit losses and improving the efficiency and stability of the system. However, the disadvantage of the traditional magnetic core is that its weight usually accounts for 50% - 70% of the effective materials of the electromagnetic device, there is a saturation effect, resulting in non-linear magnetic circuit characteristics, and it is prone to iron core losses and heat generation under the action of an alternating magnetic field, so additional heat dissipation and cooling measures are required.

[0004] The second is the air core, which forms a closed magnetic circuit through air or gas media, and is usually applied to high-frequency converters and other high-frequency electromagnetic devices. The air core has a low magnetic permeability, is suitable for low-loss and high-frequency applications, and helps to reduce the energy loss of the magnetic circuit. However, due to the inability to precisely control the magnetic flux path of the air core, the magnetic leakage phenomenon is serious, the energy conversion efficiency is low, and the performance is difficult to compare with that of the traditional magnetic core, so its application scenario is relatively limited.

[0005] It can be known from Chinese patents CN202011350276.4 and CN202311372958.9 that according to the vector magnetic circuit theory, the performance of the magnetic core is determined by three basic magnetic circuit parameters: magnetic resistance, magnetic induction, and magnetic capacitance. By adding external magnetic circuit elements, these parameters can be effectively adjusted, thereby realizing the regulation of the magnetic core performance. Currently, the research on magnetic cores mainly focuses on the design and improvement of traditional magnetic cores and air cores. Once the magnetic core is manufactured and put into a stable working state, its magnetic circuit parameters are usually fixed, and the characteristics of the magnetic core are also difficult to adjust and optimize. Therefore, how to innovate the magnetic core design by adding external magnetic circuit elements (such as magnetic induction elements, etc.) to form a new type of magnetic core and effectively improve various performance indicators of the magnetic circuit, such as power, efficiency, and coupling coefficient, etc., has not been fully studied and solved at present. Summary of the Invention

[0006] Technical problem: Aiming at the deficiencies of the background technology, the present invention proposes a virtual magnetic core constructed by using the vector magnetic circuit principle and its application method. It uses the vector magnetic circuit principle to construct a virtual magnetic circuit from multiple vector magnetic circuit elements, whose magnetic conductivity is similar to or better than that of an actual magnetic core, forming a virtual magnetic core. By reasonably configuring and parameter-adjusting each vector magnetic circuit element, the engineering design and on-line adjustment of the magnetic circuit parameters of the virtual magnetic core are realized, the amplitude and phase of the magnetic flux in the magnetic circuit can be effectively controlled, thereby affecting the magnetic circuit power, and the overall performance of the magnetic circuit is optimized. And based on this, an application method is proposed to construct electromagnetic devices such as transformers, reactors, and motors by using the virtual magnetic core, which is expected to significantly reduce the weight and volume of the electromagnetic devices.

[0007] Technical solution: To solve the above technical problems, the present invention first proposes a virtual magnetic core constructed by using the vector magnetic circuit principle. A plurality of vector magnetic circuit elements and a plurality of exciting windings are respectively coupled on the magnetic flux loop of the virtual magnetic core to jointly construct a virtual magnetic circuit, forming a virtual magnetic core, and using this virtual magnetic core to replace a part of the traditional magnetic core or completely replace the traditional magnetic core; by configuring the circuit elements connected in each vector magnetic circuit element, the magnetic circuit parameters of the virtual magnetic core are adjusted, the amplitude and phase of the magnetic flux in the magnetic circuit are controlled, the exciting current of the magnetic circuit is adjusted, and the active power and reactive power of the magnetic circuit are affected;

[0008] The vector magnetic circuit element forming the virtual magnetic core is to connect a capacitive element in a magnetic induction closed coil to form a vector magnetic circuit element with a negative magnetic resistance value and a positive magnetic induction value; according to the vector magnetic circuit theory, the expression of the equivalent magnetic circuit impedance under sinusoidal excitation is: where, is the equivalent magnetic impedance of the vector magnetic circuit element, N represents the number of turns of the magnetic induction closed coil, ω is the angular frequency of the magnetomotive force, C is the capacitance value of the capacitive element, and R is the resistance value of the magnetic induction closed coil; its magnetic impedance includes a negative magnetic resistance term and a positive magnetic reactance term, where the negative magnetic resistance term can partially or completely offset the air magnetic resistance of the target magnetic circuit. If the magnetic induction coil is made of superconducting material, the resistance R is approximately 0, and there is no positive magnetic reactance term.

[0009] The vector magnetic circuit element forming the virtual magnetic core is to connect an active circuit element with a negative resistance in a magnetic induction closed coil, and its magnetic circuit characteristic presents a negative magnetic induction, and the equivalent magnetic reactance value is: where, is the equivalent magnetic reactance of the vector magnetic circuit element, N represents the number of turns of the magnetic induction closed coil, and -R is the sum of the resistance value of the magnetic induction closed coil and the equivalent negative resistance value of the active circuit element; its magnetic impedance is a negative magnetic reactance term, which can partially or completely offset the positive magnetic reactance, so that the magnetic impedance of the entire magnetic circuit is approximately equal to or less than the magnetic impedance of the real magnetic core.

[0010] The vector magnetic circuit elements in the virtual magnetic core are arranged in various ways along the magnetic flux direction, including in series, parallel, cascade, or forming a nested structure in space; the vector magnetic circuit elements with different arrangements correspond to different magnetic circuit parameters, and through the arrangement of the vector magnetic circuit elements in practical applications, different effects are produced on the magnetic motive force and magnetic circuit variables of the magnetic flux in the magnetic circuit.

[0011] The vector magnetic circuit elements in the virtual magnetic core adopt rectangular, circular, polygonal and concentric structures, as well as different winding forms and turn configurations according to design requirements. The vector magnetic circuit elements with different geometric topologies and winding methods endow the magnetic circuit with different equivalent magnetic circuit parameters, and through the topological structure and layout method of the vector magnetic circuit elements in practical applications, different effects are produced on the magnetic motive force and magnetic circuit variables of the magnetic flux in the magnetic circuit.

[0012] The geometric shape, spatial arrangement, size, type and quantity of the required vector magnetic circuit elements of the virtual magnetic core are determined by the actual application requirements. (This determination means that if six vector magnetic circuit elements need to be placed on the magnetic circuit, they can be placed in a 3×2 arrangement, or a 2×2×2 arrangement, or a 3×2×1 arrangement. The specific effects need to be determined according to the actual needs of the user)

[0013] The application method of the virtual magnetic core constructed by using the vector magnetic circuit principle in the present invention uses the virtual magnetic core and the conductor coil to form various electromagnetic devices with the alternating magnetic field as the medium, including transformers, reactors, motors, etc.

[0014] For the target magnetic circuit, that is, the object to be applied, to achieve that under the preset target magnetic flux condition of the target magnetic circuit, the magnetic impedance of the magnetic circuit is minimized as much as possible, and the exciting current of the magnetic circuit, that is, the magnetic motive force, is reduced, specifically as follows:

[0015] S1. According to the physical structure and actual working conditions of the target magnetic circuit, including frequency and temperature, calculate the magnetic circuit parameters before adding the virtual magnetic core, including the magnetic flux, magnetic resistance and magnetic reactance of the magnetic circuit;

[0016] S2. Determine the specific application form of the virtual magnetic core, including partial replacement or complete replacement, and combine the calculated magnetic circuit parameters to determine the quantity and position of the vector magnetic circuit elements in the virtual magnetic core, and calculate the magnetic circuit parameters of these vector magnetic circuit elements;

[0017] S3. Add the configured vector magnetic circuit elements to the target magnetic circuit to construct a virtual magnetic core;

[0018] S4. On the premise of not affecting the normal operation of the device, utilize the negative magnetic circuit parameters of the vector magnetic circuit elements in the virtual magnetic core, including negative magnetic resistance and negative magnetic induction, to weaken the positive magnetic circuit parameters in the magnetic circuit; by continuously adjusting the configuration of the vector magnetic circuit elements in the virtual magnetic core, optimize the magnetic impedance characteristics of the magnetic circuit, ensure that the excitation current, i.e., magnetomotive force, of the target magnetic circuit is minimized under the preset target magnetic flux condition, and make the virtual magnetic core approach or be superior to the real magnetic core in key performance indicators.

[0019] The method is applicable to any magnetic core that can form a closed magnetic circuit, and there are no specific restrictions on the physical properties of the target magnetic circuit, such as shape, material, or structure.

[0020] The magnetic circuit parameters of the selected vector magnetic circuit elements are time-invariant magnetic circuit parameters or time-varying magnetic circuit parameters. As long as their application does not affect the normal operation of the target magnetic circuit, there are no specific restrictions on the specific form of the magnetic circuit parameters. (Time-invariant magnetic circuit parameters are those that do not change with time and can usually be realized by materials such as metal conductors; time-varying parameters are those that change with time and can usually be realized by materials such as superconductors)

[0021] Furthermore, the application method of the virtual magnetic core proposed by the present invention is applicable to any electromagnetic device including a magnetic circuit structure, including but not limited to reactors, transformers, and motors. In addition, there are no specific restrictions on the specific form of the target magnetic circuit, such as physical properties like shape, material, and structure.

[0022] Beneficial effects: Compared with the prior art, the present invention adopts the above technical solutions and has the following technical effects:

[0023] (1) The virtual magnetic core designed by the present invention and its application method are different from traditional magnetic cores and air cores. An innovative construction scheme of the virtual magnetic core is proposed. On the premise of ensuring that the magnetic circuit performance is not affected, the virtual magnetic core adjusts the magnetic circuit parameters by partially or completely replacing the traditional magnetic core or air core, controls the amplitude and phase of the magnetic flux in the magnetic circuit, regulates the excitation current (magnetomotive force) of the magnetic circuit, optimizes the distribution of active power and reactive power, improves the power-to-weight ratio of the electromagnetic device, and improves the overall performance of the magnetic circuit;

[0024] (2) The virtual magnetic core designed by the present invention and its application method. The virtual magnetic core is only composed of multiple vector magnetic circuit elements, which significantly reduces the overall weight of the magnetic core compared with traditional magnetic cores, and overcomes the problems existing in traditional magnetic cores, such as easy saturation, large losses, serious heating, and difficult heat dissipation. In addition, its structural characteristics make the virtual magnetic core easy to fold, pack, and transport, facilitating efficient circulation and use in practical applications;

[0025] (3) The virtual magnetic core designed by the present invention and its application method. The magnetic flux path of the virtual magnetic core can be flexibly planned according to actual requirements, and its magnetic circuit parameters can be adjusted online, greatly improving the flexibility and freedom of magnetic core design. Compared with the air core, under the same target magnetic flux condition, the virtual magnetic core requires a smaller exciting current, has a higher transmission efficiency, and at the same time maintains stable electromagnetic coupling and lower leakage magnetic flux. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural diagram of the virtual magnetic core of the present invention.

[0027] Figure 2 It is a schematic diagram of a partial or complete magnetic circuit composed of the virtual magnetic core of the present invention; Figure 2 In (a), a closed magnetic circuit is completely composed of a virtual magnetic core, Figure 2 In (b), a closed magnetic circuit is composed of a virtual magnetic core and a traditional magnetic core.

[0028] Figure 3 It is a vector magnetic circuit element with negative magnetic resistance and positive magnetic reactance of the present invention and its equivalent magnetic circuit; Figure 3 In (a), a vector magnetic circuit element is composed of a magnetic induction element and a capacitance element, Figure 3 In (b), it is an equivalent magnetic circuit diagram of the vector magnetic circuit element.

[0029] Figure 4 It is a vector magnetic circuit element with negative magnetic reactance of the present invention and its equivalent magnetic circuit; Figure 4 In (a), a vector magnetic circuit element is composed of a magnetic induction element and an active circuit element, Figure 4 In (b), it is an equivalent magnetic circuit diagram of the vector magnetic circuit element,

[0030] Figure 5 It is a winding configuration diagram of the vector magnetic circuit element in the virtual magnetic core of the present invention. Figure 5 In (a), it is circular winding, Figure 5 In (b), it is rectangular winding, Figure 5 In (c), it is polygonal winding, Figure 5 In (d), it is concentric winding.

[0031] Figure 6 It is a flowchart of the application method of the virtual magnetic core of the present invention.

[0032] Figure 7 It is a schematic diagram of the application principle of the virtual magnetic core of the present invention.

[0033] Figure 8 It is the primary side voltage, secondary side voltage, and exciting current when the virtual magnetic core is not added in the present invention.

[0034] Figure 9The primary voltage, secondary voltage, and exciting current when the negative magnetoresistance vector magnetic circuit element is added to the present invention.

[0035] Figure 10 The primary voltage, secondary voltage, and exciting current when the negative magnetic induction vector magnetic circuit element is added to the present invention.

[0036] Figure 11 The waveforms of the primary voltage, secondary voltage, and exciting current of the virtual magnetic core when the load of the present invention is 10 Ω.

[0037] Figure 12 The waveforms of the primary voltage, secondary voltage, and exciting current of the traditional magnetic core when the load of the present invention is 10 Ω. Detailed implementation manners

[0038] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as such herein.

[0040] As the carrier of the magnetic circuit, the magnetic core not only provides a clear and predictable path for the magnetic flux, but also can effectively concentrate and guide the magnetic field energy. Existing magnetic cores are mainly divided into two categories. The first category is the traditional magnetic core, which is an important part of electromagnetic devices such as motors, transformers, and reactors.

[0041] The second category is the air core. Its magnetic flux path depends on air or other gas media to close, there is no magnetic saturation problem, and the heat dissipation is better. However, the magnetic core is removed in electromagnetic devices such as air-core transformers, and the magnetic flux path cannot be effectively planned. Whether it is a traditional magnetic core or an air core, once manufactured, its magnetic circuit parameters are fixed in a stable working environment, and it is difficult to realize the on-line adjustment of the magnetic core performance.

[0042] To solve the above problems, the present invention first proposes a virtual magnetic core constructed using the vector magnetic circuit principle, as shown in Figure 1 and Figure 2As shown, it constructs a virtual magnetic circuit from multiple vector magnetic circuit elements, which can partially or completely replace a traditional magnetic core or an air core to form a closed magnetic circuit. Its magnetic permeability is similar to or even better than that of a real magnetic core, forming a virtual magnetic core. By reasonably configuring the circuit elements connected in each vector magnetic circuit element, the magnetic circuit parameters of the virtual magnetic core can be adjusted, the amplitude and phase of the magnetic flux in the magnetic circuit can be controlled, the exciting current (magnetomotive force) of the magnetic circuit can be regulated, and the active power and reactive power of the magnetic circuit can be affected.

[0043] Furthermore, the vector magnetic circuit element that constitutes the virtual magnetic core is formed by connecting a capacitive element in a magnetic induction closed coil, forming a vector magnetic circuit element with a negative magnetic resistance value and a positive magnetic induction value, as Figure 3 shown. According to the vector magnetic circuit theory, the expression for the equivalent magnetic circuit impedance under sinusoidal excitation is: where, is the equivalent magnetic impedance of the vector magnetic circuit element, N represents the number of turns of the magnetic induction closed coil, ω is the angular frequency of the magnetomotive force, C is the capacitance value of the capacitive element, and R is the resistance value of the magnetic induction closed coil. Its magnetic impedance includes a negative magnetic resistance term and a positive magnetic reactance term, where the negative magnetic resistance term can partially or completely cancel out the magnetic resistance of the target magnetic circuit.

[0044] Furthermore, the vector magnetic circuit element that constitutes the virtual magnetic core is formed by connecting an active circuit element with a negative resistance in a magnetic induction closed coil, as Figure 4 shown. Its magnetic circuit characteristic presents a negative magnetic induction, and the equivalent magnetic reactance value is: where, is the equivalent magnetic reactance of the vector magnetic circuit element, N represents the number of turns of the magnetic induction closed coil, and -R is the sum of the resistance value of the magnetic induction closed coil and the equivalent negative resistance value of the active circuit element. Its magnetic impedance is a negative magnetic reactance term, which can partially or completely cancel out the aforementioned positive magnetic reactance, so that the magnetic impedance of the entire magnetic circuit is approximately equal to or less than the magnetic impedance of the real magnetic core.

[0045] Furthermore, the vector magnetic circuit elements in the virtual magnetic core can be arranged in various ways along the magnetic flux direction, including in series, in parallel, in cascade, or even forming a nested structure in space. The vector magnetic circuit elements with different arrangement methods correspond to different magnetic circuit parameters, and through their unique configuration methods, they have different effects on various variables in the magnetic circuit.

[0046] Furthermore, the vector magnetic circuit elements in the virtual magnetic core can adopt different winding forms and turn configurations according to design requirements, such as rectangular, circular, polygonal, and concentric structures, as Figure 5 shown. The vector magnetic circuit elements with different geometric topologies and winding methods give different equivalent magnetic circuit parameters to the magnetic circuit, and through their unique topological structures and arrangement methods, they have different effects on various variables in the magnetic circuit.

[0047] Furthermore, the geometry, size, type, and quantity of the required vector magnetic circuit elements of the virtual magnetic core are determined by the actual application requirements, such as Figure 2 as shown

[0048] In addition, the present invention adopts the following technical solutions to solve the above technical problems:

[0049] The present invention designs an application method for the virtual magnetic core, such as Figure 6 as shown, various electromagnetic devices such as reactors, transformers, and motors that use an alternating magnetic field as a medium can be formed by using the virtual magnetic core and the conductor coil

[0050] Furthermore, according to the application method of the virtual magnetic core described above, for the target magnetic circuit, the following steps are taken to minimize the magnetic impedance of the magnetic circuit and reduce the excitation current (magnetomotive force) of the magnetic circuit under the preset target magnetic flux condition. The schematic diagram is as Figure 7 shown, and the details are as follows:

[0051] S1. According to the physical structure and actual working conditions (such as frequency, temperature, etc.) of the target magnetic circuit, calculate the magnetic circuit parameters before adding the virtual magnetic core, including the magnetic flux, magnetic resistance, and magnetic reactance of the magnetic circuit, etc.;

[0052] S2. Determine the specific application form of the virtual magnetic core (such as partial replacement or complete replacement), and combine the calculated magnetic circuit parameters to determine the quantity and position of the vector magnetic circuit elements in the virtual magnetic core, and calculate the magnetic circuit parameters of these vector magnetic circuit elements;

[0053] S3. Add the configured vector magnetic circuit elements to the target magnetic circuit to construct a virtual magnetic core;

[0054] S4. On the premise of not affecting the normal operation of the device, use the negative magnetic circuit parameters (such as negative magnetic resistance, negative magnetic induction) of the vector magnetic circuit elements in the virtual magnetic core to gradually weaken the positive magnetic circuit parameters in the magnetic circuit. By continuously adjusting the configuration of the vector magnetic circuit elements in the virtual magnetic core, optimize the magnetic impedance characteristics of the magnetic circuit to ensure that the excitation current (magnetomotive force) of the target magnetic circuit is minimized under the preset target magnetic flux condition, so that the virtual magnetic core meets or exceeds the real magnetic core in key performance indicators.

[0055] Furthermore, in the application method of the virtual magnetic core proposed by the present invention, in step S1, the method is applicable to any magnetic core that can form a closed magnetic circuit, and there are no specific restrictions on the physical properties such as the shape, material, or structure of the target magnetic circuit.

[0056] Further, in the application method of the virtual magnetic core proposed by the present invention, in step S3, the magnetic circuit parameters of the selected vector magnetic circuit element can be time-invariant magnetic circuit parameters (such as metal conductors) or time-varying magnetic circuit parameters (such as superconducting materials), as long as they do not affect the normal operation of the target magnetic circuit during application, and the specific form of the magnetic circuit parameters is not limited.

[0057] Further, the application method of the virtual magnetic core proposed by the present invention is applicable to any electromagnetic device including a magnetic circuit structure, including but not limited to reactors, transformers, and motors. In addition, specific physical properties of the target magnetic circuit, such as shape, material, and structure, are not specifically limited.

[0058] Next, the virtual magnetic core constructed using the vector magnetic circuit principle and its application method proposed by the present invention are verified. The above design scheme is applied in practice, and the feasibility of the present invention is specifically verified through the built experimental device. The verification device consists of a signal generator, a power amplifier, a target magnetic circuit, a power analyzer, an oscillograph, an LCR tester, a voltage differential probe, and a high-frequency current probe. In the experiment, the signal generator and the power amplifier drive the excitation windings of the virtual magnetic core and the traditional magnetic core to form a closed magnetic circuit and generate an alternating magnetic flux. The LCR tester is used to measure the circuit parameters of the vector magnetic circuit element in the virtual magnetic core, and the voltage differential probe and the high-frequency current probe capture the primary voltage, excitation current, and secondary voltage. The experimental data are recorded and analyzed by the power analyzer and the oscillograph. Finally, the magnetic circuit parameters of the target magnetic circuit are calculated based on the collected experimental data to verify the effectiveness and feasibility of the design and application method of the virtual magnetic core.

[0059] The experimental objective is to use the virtual magnetic core constructed using the vector magnetic circuit principle and its application method described in the present invention to replace the air core in the transformer, thereby weakening the magnetic impedance of the target magnetic circuit, reducing the excitation current, improving the coupling ability of the target magnetic circuit, and minimizing the excitation current (magnetomotive force) of the target magnetic circuit, so that the virtual magnetic core transformer is close to or superior to the traditional magnetic core transformer in key performance indicators, to verify the feasibility and engineering application value of this patent in electromagnetic devices.

[0060] In the experiment, the target magnetic circuit is realized by a transformer with an air core. The primary and secondary windings are both made of 0.1 mm × 100 litz wire and wound on a magnetic core skeleton of EC90 specification in a double-wire parallel manner. The number of turns of the windings is 23. Under no-load conditions, by measuring the primary voltage u1, secondary voltage u2, and excitation current i1 of the air-core transformer, as Figure 8As shown, the magnetomotive force and magnetic flux of the air-core transformer can be calculated. Based on Kirchhoff's magnetomotive force law in vector magnetic circuit theory, the magnetic circuit is analyzed using the above measurement data, and it is calculated that at a working frequency of 41.2 kHz, the magnetic resistance parameter of this magnetic circuit is 7.85×10 8 H -1 .

[0061] Since the transformer composed of an air core only has a magnetic resistance parameter, to weaken the positive magnetic resistance parameter in the magnetic circuit, a vector magnetic circuit element with negative magnetic resistance is added to the target magnetic circuit to form a virtual magnetic core, as Figure 7 shown. The magnetic circuit element is wound with Litz wire of 0.1 mm×400, with 43 turns, and a capacitor C = 0.47 μF is connected. At a working frequency of 41.2 kHz, the magnetomotive force of the transformer reaches the minimum. At this time, the primary voltage u1, the secondary voltage u2, and the exciting current i1 are in phase, as Figure 9 shown. When the secondary voltage u2 is 45.14 V, the primary voltage u1 is 45.54 V, the exciting current i1 is 0.334 A, and the voltage u c of the magnetic circuit element is 113.1 V, and the current i c is 14.25 A. The coupling coefficient of the transformer is increased to 0.990. Under these conditions, the power factor of the transformer reaches 0.999, indicating that its magnetic resistance parameter has been effectively weakened to zero. However, the introduced magnetic circuit element simultaneously generates a magnetic reactance parameter, and its value is 1.00×10 7 H -1 , verifying the Figure 7 correctness.

[0062] Since there is still a positive magnetic reactance parameter in the target magnetic circuit at this stage, to further optimize the magnetic circuit performance, a magnetic circuit element with negative magnetic induction parameter is added to the constructed virtual magnetic core, as Figure 7 shown. Specifically, two magnetic circuit elements with negative magnetic induction parameters, each wound with Dupont wire and having 2 turns, are introduced into the virtual magnetic core, and their equivalent negative resistance value is -5.8 Ω. After adding these magnetic circuit elements, as Figure 10 shown, while keeping the same secondary voltage u2, the exciting current i1 drops to 20 mA, and the magnetic impedance of the magnetic circuit is reduced to 6.07×10 4 H -1 , realizing the minimization of the exciting current (magnetomotive force), and verifying the effectiveness and feasibility of the virtual magnetic core constructed by using the vector magnetic circuit principle and its application method proposed in the present invention.

[0063] To further verify the effectiveness of the virtual magnetic core, the magnetic circuit performance of transformers with traditional magnetic cores and virtual magnetic cores was compared. The traditional magnetic core consists of a pair of PC40 ferrite magnetic cores with an EC90 specification, and its mass is 660 g; while the mass of the transformer with a virtual magnetic core is 270 g, among which the mass of the primary and secondary windings and the winding skeleton is 52 g, and the mass of the additional vector magnetic circuit elements is 218 g. Compared with the traditional magnetic core, the mass of the transformer with a virtual magnetic core is reduced by 59.1%, achieving the lightweight design of the transformer.

[0064] Figure 11 and Figure 12 respectively show the waveforms of the primary voltage u1, exciting current i1, secondary voltage u2 and load current i2 of the transformer under the traditional magnetic core and the virtual magnetic core. The results show that the virtual magnetic core can not only achieve magnetic circuit performance similar to that of the traditional magnetic core, but also significantly reduce the weight and volume of the electromagnetic device, further verifying the effectiveness and feasibility of the virtual magnetic core constructed based on the vector magnetic circuit principle and its application method.

[0065] In summary, the present invention proposes a virtual magnetic core constructed by using the vector magnetic circuit principle and its application method. The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. The target magnetic circuit is not limited to the transformer. Any electromagnetic equipment that can include a closed magnetic circuit and equivalent modifications or changes made by those of ordinary skill in the art according to the content disclosed in the present invention should be included in the protection scope recorded in the claims.

[0066] The above is only a partial embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A virtual magnetic core constructed using the principle of vector magnetic circuit, characterized in that: A plurality of vector magnetic circuit elements and a plurality of excitation windings are coupled to the magnetic flux loop of the virtual magnetic core to construct a virtual magnetic circuit and form a virtual magnetic core, and the virtual magnetic core is used to replace a part of the traditional magnetic core or completely replace the traditional magnetic core; by configuring the circuit elements connected to each vector magnetic circuit element, the magnetic circuit parameters of the virtual magnetic core are adjusted, the amplitude and phase of the magnetic flux in the magnetic circuit are controlled, the excitation current of the magnetic circuit is adjusted, and the active power and reactive power of the magnetic circuit are affected; The vector magnetic circuit element forming the virtual magnetic core is formed by connecting a capacitor element in the magnetic induction closed coil to form a vector magnetic circuit element with a negative magnetic resistance value and a positive magnetic induction value; the expression of the equivalent magnetic circuit impedance under sinusoidal excitation is: in, is the equivalent magnetic impedance of the vector magnetic circuit element, N represents the number of turns of the magnetic induction closed coil, ω is the angular frequency of the magnetomotive force, C is the capacitance value of the capacitor element, and R is the resistance value of the magnetic induction closed coil; its magnetic impedance includes a negative magnetic resistance term and a positive magnetic reactance term, wherein the negative magnetic resistance term can partially or completely offset the air magnetic resistance of the target magnetic circuit.

2. A virtual magnetic core constructed using the principle of vector magnetic circuit, characterized in that: A plurality of vector magnetic circuit elements and a plurality of excitation windings are coupled to the magnetic flux loop of the virtual magnetic core to construct a virtual magnetic circuit and form a virtual magnetic core, and the virtual magnetic core is used to replace a part of the traditional magnetic core or completely replace the traditional magnetic core; by configuring the circuit elements connected to each vector magnetic circuit element, the magnetic circuit parameters of the virtual magnetic core are adjusted, the amplitude and phase of the magnetic flux in the magnetic circuit are controlled, the excitation current of the magnetic circuit is adjusted, and the active power and reactive power of the magnetic circuit are affected; The vector magnetic circuit element that forms the virtual magnetic core is an active circuit element with negative resistance connected to the magnetic induction closed coil. Its magnetic circuit characteristic presents negative magnetic induction, and the equivalent magnetic reactance value is: in, is the equivalent magnetic reactance of the vector magnetic circuit element, N represents the number of turns of the magnetic induction closed coil, -R is the sum of the resistance value of the magnetic induction closed coil and the equivalent negative resistance value of the active circuit element; its magnetic impedance is the negative magnetic reactance term.

3. The virtual magnetic core constructed using the vector magnetic circuit principle according to claim 1 or 2, characterized in that: The vector magnetic circuit elements in the virtual core are arranged along the magnetic flux direction in a variety of ways, including series, parallel, cascade, or forming a nested structure in space.

4. The virtual magnetic core constructed using the vector magnetic circuit principle according to claim 1 or 2, characterized in that: The vector magnetic circuit elements in the virtual magnetic core adopt rectangular, circular, polygonal and concentric structures as well as different winding forms and turns configurations according to design requirements. Vector magnetic circuit elements with different geometric topologies and winding methods give the magnetic circuit different equivalent magnetic circuit parameters.

5. An application method of a virtual magnetic core constructed using the vector magnetic circuit principle as claimed in any one of claims 1 to 4, characterized in that: Virtual magnetic cores and conductor coils are used to form various electromagnetic devices using alternating magnetic fields as media, including reactors, transformers, and motors.

6. The application method of the virtual magnetic core constructed by using the vector magnetic circuit principle according to claim 5 is characterized in that: For the target magnetic circuit, in order to achieve the target magnetic circuit under the preset target magnetic flux condition, reduce the magnetic impedance of the magnetic circuit and reduce the magnetic circuit excitation current, as follows: S1. Calculate the magnetic circuit parameters before adding the virtual magnetic core, including the magnetic flux, magnetic resistance and magnetic reactance of the magnetic circuit, according to the physical structure of the target magnetic circuit and the actual working conditions including frequency and temperature; S2. Determine the specific application form of the virtual magnetic core, including partial replacement or complete replacement, and determine the number and position of the vector magnetic circuit elements in the virtual magnetic core in combination with the calculated magnetic circuit parameters, and calculate the magnetic circuit parameters of these vector magnetic circuit elements; S3, adding the configured vector magnetic circuit elements to the target magnetic circuit to construct a virtual magnetic core; S4. Under the premise of not affecting the normal operation of the equipment, the negative magnetic circuit parameters of the vector magnetic circuit elements in the virtual magnetic core, including negative magnetic resistance and negative magnetic induction, are used to weaken the positive magnetic circuit parameters in the magnetic circuit; by continuously adjusting the configuration of the vector magnetic circuit elements in the virtual magnetic core, the magnetic impedance characteristics of the magnetic circuit are optimized to minimize the excitation current of the target magnetic circuit.

7. The application method of the virtual magnetic core constructed by using the vector magnetic circuit principle according to claim 5, characterized in that: The method is applicable to any magnetic core that can form a closed magnetic circuit, and does not impose specific restrictions on the shape, material, spatial layout or physical properties of the structure of the target magnetic circuit.

8. The application method of the virtual magnetic core constructed by using the vector magnetic circuit principle according to claim 5, characterized in that: The magnetic circuit parameters of the selected vector magnetic circuit elements are time-invariant magnetic circuit parameters or time-varying magnetic circuit parameters.

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