Design method of low-noise transformer

Abstract

The invention discloses a low-noise transformer design method, which comprises the following steps of: 1, establishing a transformer electromagnetic design model based on a basic principle of transformer design, and obtaining a relationship between each design parameter and an electromagnetic parameter of a transformer; step 2, considering stress influence, combining a transformer material coupling magnetostriction strain theory to establish a transformer vibration model, and associating stress with acceleration; and step 3, establishing a transformer electromagnetic-vibration optimization design model, and designing the iron core diameter D, the number of turns NT, the winding axial height Hl and the maximum flux density Bm of the transformer by taking the minimum vibration acceleration effective value ms as a target and taking the transformer mass G and the coil voltage Us as constraints based on the relationship between the basic size and the electromagnetic load of the transformer and the vibration model.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer design, and in particular to a low-noise transformer design method. Background Art

[0002] Transformers are one of the key equipment in the electrical system. In ships, they transform voltage to supply the power needs of various equipment and systems on board, such as drive equipment, navigation systems, and communication equipment. However, transformers will inevitably vibrate, and the noise caused by vibration may cause fatigue and fracture of metal structures, short circuit or grounding between windings, affect the electrical performance of the transformer, or interfere with the normal operation of surrounding equipment.

[0003] In the prior art, for electromagnetic noise, which accounts for a large proportion, the noise reduction measures usually adopt: 1. Reduce the gap between internal components of the transformer, use vibration-damping materials, increase structural support, etc. to reduce the mechanical vibration of the transformer; 2. Use better insulation materials and technologies to reduce the noise generated by electrical discharge inside the transformer; 3. Use shielding covers or isolation structures to reduce electromagnetic radiation, thereby reducing conducted noise; 4. Use electromagnetic compatibility design to reduce the transformer's sensitivity to external electromagnetic interference and reduce the noise generated by interference.

[0004] The above traditional transformer vibration suppression research mainly focuses on vibration mechanism and noise reduction technology, while there is less research on the direct vibration reduction design method of the transformer. In addition, the transformer may work in different environments, and the influence of stress effect on transformer vibration cannot be ignored. However, the existing technology rarely involves the relationship between stress and transformer noise and vibration, and the problem is not fully considered. Summary of the invention

[0005] The purpose of the present invention is to propose a low-noise transformer design method by considering the influence of stress on transformer operation.

[0006] The present invention provides a low-noise transformer design method, the low-noise transformer design method comprising the following steps:

[0007] Step 1: Establish a transformer electromagnetic design model based on the basic principle of transformer design to obtain the relationship between various transformer design parameters and electromagnetic parameters;

[0008] Step 2, considering the influence of stress, the transformer vibration model is established in combination with the transformer material coupled magnetostrictive strain theory to associate stress with acceleration;

[0009] Step 3: Establish the transformer electromagnetic-vibration optimization design model based on the relationship between the transformer basic size and electromagnetic load and the vibration model, and use the effective value of vibration acceleration |a rms|Minimum as the goal, with transformer quality G, coil voltage U s As a constraint, the transformer core diameter D and number of turns N T 、Winding axial height H l and maximum magnetic density B m Make a design.

[0010] Going one step further, in step 1, based on the basic principle of transformer:

[0011]

[0012] Where: N T is the number of series turns of each phase of the winding; I is the winding line current; P D It is the ratio of the effective cross-sectional area of ​​the core column to the area of ​​the circle determined by the diameter D of the core column; A is the line load; B m is the maximum magnetic flux density; m is the number of phases; H l is the axial height of the winding; f is the frequency; φ m is the maximum magnetic flux; E is the electromotive force, is the total capacity of the transformer;

[0013] Solving for this yields:

[0014]

[0015] Where: K T represents the utilization factor of the transformer, k is the volume factor, and W is the volume of the transformer; the utilization factor of the transformer is:

[0016]

[0017] The relationship between transformer mass and maximum magnetic flux density is:

[0018]

[0019] Where: G is the mass of the transformer; ρ is the density of the transformer material.

[0020] Furthermore, in step 1, the core volume expression is:

[0021]

[0022] Where: K Fe is the overlap coefficient; a z is the center distance between two adjacent core columns; h1 is the length from the bottom of the core column to the top of the transformer; A Fe is the effective cross-sectional area of ​​the core column, C1, C2, and C3 are the first to third correlation coefficients respectively;

[0023] Combining the above formulas, the total mass of the transformer can be obtained:

[0024] G(D,H l )=ρV(D,H l )=C1ρH l D 2 +C2ρD 2 +C3ρD 3 .

[0025] Furthermore, in step 2, the relationship between saturation magnetostriction and stress (Jiles-Atherton) is usually:

[0026] ε s (σ)=ε0+λσ

[0027] Where: ε0 is the saturated magnetostriction at zero atmospheric pressure; λ is the stress coefficient of magnetostriction, which represents the change in magnetostriction caused by a unit stress change; σ is the applied stress;

[0028] Under the action of the magnetic field, the small deformation of the silicon steel sheet meets the following conditions:

[0029]

[0030] Where: H c is the core coercivity, ε s is the relationship between the saturation magnetostriction rate and stress, L is the original axial size of the silicon steel sheet, and ΔL represents the axial expansion of the silicon steel sheet.

[0031] The maximum axial expansion of the core silicon steel sheet caused by magnetostriction is:

[0032]

[0033] The acceleration of the core vibration caused by the magnetostriction of the silicon steel sheet is:

[0034]

[0035] Where: B s is the saturation magnetic flux density, t represents time, U s is the coil voltage, ω is the angular velocity, and S is the transformer cross-sectional area;

[0036] Core acceleration a and core diameter D, winding axial height H l The relationship is as follows:

[0037]

[0038] The effective value of acceleration can be expressed as:

[0039]

[0040] Furthermore, the transformer electromagnetic-vibration optimization design model is:

[0041]

[0042] The constraints are:

[0043]

[0044] Where: C4 is the custom coefficient, G max is the maximum transformer weight, (U s ) max is the maximum value of coil voltage;

[0045] Genetic algorithm is used to solve the transformer electromagnetic-vibration optimization design model.

[0046] The beneficial effects of the present invention are:

[0047] The present invention studies how to reduce the vibration noise of the transformer from the design end, reduces the vibration noise from the source, and ensures the safety of the transformer during operation to a great extent.

[0048] The present invention deeply studies the relationship between stress and magnetostriction, relates the two to design basic parameters of the transformer, and enables the transformer to maintain low noise and low vibration under different working conditions.

[0049] The present invention can utilize genetic algorithms to automatically solve the model, thereby accelerating the solving speed and solving efficiency and meeting the electromagnetic and vibration noise requirements of the transformer in a complex environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The advantages of the above and additional aspects of the present invention will become apparent and easily understood in the description of the embodiments in conjunction with the following drawings, in which:

[0051] Figure 1 is a flow chart of a low noise transformer design method provided according to an embodiment of the present invention;

[0052] Figure 2 It is a main structural diagram of a transformer provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0054] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0055] like Figure 1 As shown, the present invention provides a low noise transformer design method, the low noise transformer design method comprises the following steps:

[0056] Step 1: Establish a transformer electromagnetic design model based on the basic principles of transformer design to obtain the relationship between the transformer design parameters and electromagnetic parameters.

[0057] First, we need to establish the electromagnetic model of the transformer. The main parameters of the transformer are as follows: Figure 2 . Using the basic principle of transformer, the relationship between the basic size of transformer and electromagnetic load is derived. From the basic principle of transformer, we can get:

[0058]

[0059] Where: N T is the number of series turns of each phase of the winding; I is the winding line current; P D It is the ratio of the effective cross-sectional area of ​​the core column to the area of ​​the circle determined by the diameter D of the core column; A is the line load; B m is the maximum magnetic flux density; m is the number of phases; H l is the axial height of the winding; f is the frequency; φ m is the maximum magnetic flux; E is the electromotive force, is the total capacity of the transformer.

[0060] Solving the above system of equations yields:

[0061]

[0062]

[0063] Where: K T It represents the utilization factor of the transformer, k is the volume factor, and W is the volume of the transformer.

[0064]

[0065] From equations (1) to (4), the relationship between transformer mass and maximum magnetic flux density is:

[0066]

[0067] Where: G is the mass of the transformer; ρ is the density of the transformer material.

[0068] The volume of the core includes the volume of the core column, the part between the center distances of the two side columns, and the actual part of the four corners of the iron yoke. Its overall expression is:

[0069]

[0070] Where: K Fe is the overlap coefficient; a z is the center distance between two adjacent core columns; h1 is the length from the bottom of the core column to the top of the transformer; A Fe is the effective cross-sectional area of ​​the core column, C1, C2, C3 are the first to third correlation coefficients.

[0071] Combining the above formulas, the total mass of the transformer can be obtained:

[0072] G(D,H l )=ρV(D,H l )=C1ρH l D 2 +C2ρD 2 +C3ρD 3 (11)

[0073] Step 2, considering the influence of stress, the transformer vibration model is established in combination with the transformer material coupled magnetostrictive strain theory to associate stress with acceleration;

[0074] A transformer vibration model considering external stress is established. The iron core is the main vibration source of the transformer. Considering the influence of stress and electromagnetic parameters on the iron core vibration, a transformer magnetostrictive model is established.

[0075] When the transformer core is exposed to an AC excitation source, the ferromagnetic material moves periodically due to the magnetostrictive effect and electromagnetic force. The magnetostrictive coefficient ε can be expressed as the ratio of the change in length due to the magnetostrictive effect to the original length.

[0076]

[0077] Where: L is the original axial dimension of the silicon steel sheet, and ΔL represents the axial expansion and contraction of the silicon steel sheet.

[0078] The relationship between saturation magnetostriction and stress can usually be described by the following functional form:

[0079] ε s (σ)=ε0+λσ (13)

[0080] Where: ε0 is the saturated magnetostriction at zero atmospheric pressure; λ is the stress coefficient of magnetostriction, which represents the change in magnetostriction caused by a unit stress change; σ is the applied stress.

[0081] Under the action of the magnetic field, the small deformation of the silicon steel sheet meets the following conditions:

[0082]

[0083] Where: H c is the core coercivity, ε s This is the relationship between the saturation magnetostriction and stress.

[0084] By combining equation (13) and equation (14), the maximum axial expansion of the core silicon steel sheet caused by magnetostriction is:

[0085]

[0086] Combining the above formulas, the acceleration of the core vibration caused by the magnetostriction of the silicon steel sheet is:

[0087]

[0088] Where: B s is the saturation magnetic flux density, t represents time, U s is the coil voltage, ω is the angular velocity, and S is the transformer cross-sectional area;

[0089] Then, the core acceleration a is related to the core diameter D and the winding axial height H l The relationship is as follows:

[0090]

[0091] The effective value of acceleration can be expressed as:

[0092]

[0093] Step 3: Establish the transformer electromagnetic-vibration optimization design model based on the relationship between the transformer basic size and electromagnetic load and the vibration model, and use the effective value of vibration acceleration |a rmS |Minimum as the goal, with transformer quality G, coil voltage U s As a constraint, the transformer core diameter D and number of turns N T 、Winding axial height H l and maximum magnetic density B m Make a design.

[0094] The transformer electromagnetic-vibration optimization design model is:

[0095]

[0096] The constraints are:

[0097]

[0098] Where: C4 is the custom coefficient, G max is the maximum transformer weight, (U s ) max The maximum coil voltage

[0099] The above is the transformer electromagnetic-vibration optimization design model. Finally, the transformer electromagnetic-vibration optimization design model is solved using genetic algorithm.

[0100] The algorithm flow of the genetic optimization algorithm is as follows:

[0101] 1. Initialize the population: Generate a set of random individuals (genes), each of which represents a possible solution, for example, X1 = [N T 1,D1,H l 1,B m 1],X2=[N T 2,D2,H l 2,B m 2],X3=[N T 3,D3,H l 3,B m 3],X4=[N T 4,D4,H l 4,B m 4] etc.

[0102] 2. Evaluate fitness: Bring each individual into the objective function for calculation, use constraints as fitness function, and check whether the constraints are met to evaluate fitness. If an individual does not meet the constraints, it can be punished or eliminated.

[0103] 3. Selection: Select a part of individuals as parents according to the individuals with better fitness, such as X1 = [N T 1,D1,H l 1,B m 1],X2=[N T 2,D2,H l 2,B m 2],X4=[N T 4,D4,H l 4,B m 4].

[0104] 4. Crossover: Randomly select two parent individuals, such as X2 = [N T 2,D2,H l 2,B m 2],X4=[N T 4,D4,H l 4,B m 4], cross their genes to generate new offspring individuals, such as X5 = [N T 2,D2,Hl 4,B m 4],X6=[N T 4,D4,H l 2,B m 2].

[0105] 5. Mutation: Perform gene mutation operations on a portion of the offspring individuals to introduce new gene variants, such as X6 = [N T 4,D4,H l 2,B m 2] becomes X7=[N T 4,D7,H l 2,B m 2].

[0106] 6. Update the population: replace the original population with parent and offspring individuals.

[0107] 7. Repeat 2 to 6 until the termination condition is met (for example, the maximum number of iterations is reached or a satisfactory solution is found).

[0108] The above process is the transformer optimization design model solution process of the present invention.

[0109] So far, the technical route of the present invention has been described in detail, but it is easy for researchers in the field to understand that the protection scope of the present invention is obviously not limited to these specific implementations. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A low noise transformer design method, characterized in that: The low noise transformer design method comprises the following steps: Step 1: Establish a transformer electromagnetic design model based on the basic principle of transformer design to obtain the relationship between various transformer design parameters and electromagnetic parameters; Step 2, considering the influence of stress, the transformer vibration model is established in combination with the transformer material coupled magnetostrictive strain theory to associate stress with acceleration; Step 3: Establish the transformer electromagnetic-vibration optimization design model based on the relationship between the transformer basic size and electromagnetic load and the vibration model, and use the effective value of vibration acceleration |a rms |Minimum as the goal, with transformer quality G, coil voltage U s As a constraint, the transformer core diameter D and number of turns N T 、Winding axial height H l and maximum magnetic density B m Make a design.

2. The low noise transformer design method according to claim 1, characterized in that: In step 1, based on the basic principle of transformer: Where: N T is the number of series turns of each phase of the winding; I is the winding line current; P D It is the ratio of the effective cross-sectional area of ​​the core column to the area of ​​the circle determined by the diameter D of the core column; A is the line load; B m is the maximum magnetic flux density; m is the number of phases; H l is the axial height of the winding; f is the frequency; φ m is the maximum magnetic flux; E is the electromotive force, is the total capacity of the transformer; Solving for this yields: Where: K T represents the utilization factor of the transformer, k is the volume factor, and W is the volume of the transformer; the utilization factor of the transformer is: The relationship between transformer mass and maximum magnetic flux density is: Where: G is the mass of the transformer; ρ is the density of the transformer material.

3. The low noise transformer design method according to claim 2, characterized in that: In step 1, the core volume expression is: Where: K Fe is the overlap coefficient; a z is the center distance between two adjacent core columns; h1 is the length from the bottom of the core column to the top of the transformer; A Fe is the effective cross-sectional area of ​​the core column, C1, C2, and C3 are the first to third correlation coefficients respectively; Combining the above formulas, the total mass of the transformer can be obtained: <h2 style=";text-align:left;direction:ltr">G(D,H<h2 style=";text-align:left;direction:ltr"> l <h2 style=";text-align:left;direction:ltr"> )=ρV(D,H<h2 style=";text-align:left;direction:ltr"> l <h2 style=";text-align:left;direction:ltr"> )=C1ρH<h2 style=";text-align:left;direction:ltr"> l <h2 style=";text-align:left;direction:ltr"> D<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +C2ρD<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> +C3ρD<h2 style=";text-align:left;direction:ltr"> 3 <h2 style=";text-align:left;direction:ltr"> 。 4. The low noise transformer design method according to claim 1, characterized in that: In step 2, the relationship between saturation magnetostriction and stress is usually (Jiles-Atherton): e s (σ)=ε0+λσ Where: ε0 is the saturated magnetostriction at zero atmospheric pressure; λ is the stress coefficient of magnetostriction, which represents the change in magnetostriction caused by a unit stress change; σ is the applied stress; Under the action of the magnetic field, the small deformation of the silicon steel sheet meets the following conditions: Where: H c is the core coercivity, ε s is the relationship between the saturation magnetostriction rate and stress, L is the original axial size of the silicon steel sheet, and ΔL represents the axial expansion of the silicon steel sheet. The maximum axial expansion of the core silicon steel sheet caused by magnetostriction is: The acceleration of the core vibration caused by the magnetostriction of the silicon steel sheet is: Where: B s is the saturation magnetic flux density, t represents time, U s is the coil voltage, ω is the angular velocity, and S is the transformer cross-sectional area; Core acceleration a and core diameter D, winding axial height H l The relationship is as follows: The effective value of acceleration can be expressed as:

5. The low noise transformer design method according to claim 1, characterized in that: In step 3, the transformer electromagnetic-vibration optimization design model is: The constraints are: Where: C4 is the custom coefficient, G max is the maximum transformer weight, (U s ) max is the maximum value of coil voltage; Genetic algorithm is used to solve the transformer electromagnetic-vibration optimization design model.

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