CN113053623B

CN113053623B - DD-PS strong anti-offset loose coupling transformer and parameter determination method thereof

Info

Publication number: CN113053623B
Application number: CN202110291327.9A
Authority: CN
Inventors: 姚友素; 庄廷伟; 麦建伟; 王懿杰; 刘晓胜; 徐殿国
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2021-03-18
Filing date: 2021-03-18
Publication date: 2022-06-07
Anticipated expiration: 2041-03-18
Also published as: CN113053623A

Abstract

The invention discloses a DD-PS (direct-wound-series) strong anti-offset loose-coupled transformer and a parameter determination method thereof, belongs to the technical field of wireless power transmission, and solves the problem of low system efficiency caused by weak anti-offset capability of the traditional compensation topology. By adopting the method for determining the parameters of the loose coupling transformer, all the parameters of the loose coupling transformer can be rapidly determined, and an optimal solution meeting application requirements is obtained. The invention is suitable for the technical field of wireless power transmission.

Description

DD-PS strong anti-offset loose coupling transformer and parameter determination method thereof

Technical Field

The invention belongs to the technical field of wireless power transmission, and particularly relates to an anti-offset loose coupling transformer.

Background

The traditional contact type power transmission technology has low flexibility and poor reliability, and is limited in application in many scenes. As an alternative, wireless power transmission technology has become a hot spot of research in recent years. Compared with the traditional contact type power transmission technology, the wireless power transmission technology has the advantages of flexibility, safety and reliability, and is increasingly applied to various occasions, such as electric vehicles, implanted medical equipment, consumer electronics, industrial robots, underwater electric equipment and the like.

The loose coupling transformer is a key element of a wireless power transmission system, after the primary side and the secondary side of the traditional loose coupling transformer deviate, the mutual inductance and the coupling coefficient can change greatly, the system output can change accordingly, and the requirements of a load on output voltage and current cannot be met. Some researchers have proposed some compensation topologies with a certain offset resistance, such as S/CLC, T/S, PS/S, S/SP, etc., starting from the compensation topology, but these compensation topologies have a weak offset resistance and introduce a large amount of reactive power, and the system efficiency is low.

Disclosure of Invention

The invention aims to solve the problem of low system efficiency caused by weak anti-offset capability of the existing compensation topology, and provides a DD-PS strong anti-offset loose coupling transformer and a parameter determination method thereof.

The invention relates to a DD-PS strong anti-offset loose coupling transformer, which comprises a primary side coupling mechanism and a secondary side coupling mechanism; the primary side coupling mechanism and the secondary side coupling mechanism are arranged oppositely;

the primary side coupling mechanism comprises a primary side planar solenoid coil, a primary side DD coil and a primary side ferrite magnetic core;

the primary side ferrite core is rectangular, and the primary side DD coil is arranged on the side, close to the secondary side coupling mechanism, of the primary side ferrite core and is parallel to the primary side ferrite core;

the primary side planar solenoid coil is divided into two parts which are wound on the primary side ferrite magnetic core, and the number of turns of the two parts of the primary side planar solenoid coil is the same;

the primary side planar solenoid coil is connected with the primary side DD coil in a reverse connection mode;

the secondary coupling mechanism comprises a secondary plane solenoid coil, a secondary DD coil and a secondary ferrite magnetic core;

the secondary side ferrite core is rectangular, and the secondary side DD coil is arranged on one side, close to the primary side coupling mechanism, of the secondary side ferrite core and is parallel to the secondary side ferrite core;

the secondary side planar solenoid coil is wound on the secondary side ferrite magnetic core in two parts, and the number of turns of the secondary side planar solenoid coil in the two parts is the same;

the secondary planar solenoid coil and the secondary DD coil are connected in a direct connection mode.

Furthermore, in the invention, the winding directions of the two parts of the primary planar solenoid coil are both vertical to the length direction of the primary ferrite core; the winding directions of the two parts of the secondary plane solenoid coil are both vertical to the length direction of the secondary ferrite core.

Further, in the present invention, the two parts of the primary planar solenoid coil are symmetrical about the center of the primary ferrite core; the two portions of the secondary planar solenoid coil are symmetrical about the center of the secondary ferrite core.

Further, in the present invention, the outer contour dimensions of the primary side DD coil and the secondary side DD coil are respectively equal to the outer contour dimensions of the primary side magnetic core and the secondary side magnetic core.

A method of determining parameters of an anti-migration loosely coupled transformer, the method comprising:

determining fixed size parameters and a mutual inductance value range of a primary side coupling mechanism and a secondary side coupling mechanism according to parameters of a wireless power transmission system in practical application of an anti-offset loose coupling transformer;

secondly, setting the range of the parameters to be optimized and the maximum value of the iteration times of the optimization algorithm according to the size limit of the practical application of the anti-offset loose coupling transformer;

the parameters to be optimized comprise: the number of turns of the primary side planar solenoid coil, the number of turns of the secondary side planar solenoid coil, the number of turns of the primary side DD coil, the number of turns of the secondary side DD coil, the distance between the two parts of the primary side planar solenoid coil and the distance between the two parts of the secondary side planar solenoid coil;

step three, setting the scanning step length and the range of the parameter to be optimized in the iteration according to the value of the current iteration number m;

step four, according to the scanning step length and the range of the parameters to be optimized in the iteration in the step three, the parameters to be optimized are updated in sequence by using the minimum fluctuation principle, and the mutual inductance value M of the iteration loosely-coupled transformer is obtained_{12_m}；

Step five, judging the mutual inductance value M of the iteration loose coupling transformer_{12_m}Whether the range [ M ] is satisfied_{12_min},M_{12_max}](ii) a If yes, executing a seventh step, otherwise, executing a sixth step;

step six, utilizing a formula:

sequentially updating the number of turns of the primary planar solenoid coil, the number of turns of the secondary planar solenoid coil, the number of turns of the primary DD coil and the number of turns of the secondary DD coil in the parameters to be optimized, and then updating the mutual inductance value M of the loosely coupled transformer_{12_m}Executing the step seven; where round represents the rounding function, and when i is equal to 1, 3, 5, 7, N_iRespectively showing the number of turns of the primary side planar solenoid coil, the number of turns of the primary side DD coil, the number of turns of the secondary side planar solenoid coil and the number of turns of the secondary side DD coil;

step seven, judging whether the value of the current iteration number m is equal to the maximum value of the iteration number, if so, recording the distance between two parts of the primary side planar solenoid coil, the distance between two parts of the secondary side planar solenoid coil and the number of turns of the primary side planar solenoid coil, the number of turns of the secondary side planar solenoid coil, the number of turns of the primary side DD coil and the number of turns of the secondary side DD coil which are updated in the step six, and finishing the parameter determination of the loose coupling transformer; otherwise, making the current iteration number m equal to m +1, and returning to execute the step three.

Further, in the present invention, the parameters of the wireless power transmission system to which the anti-offset loose coupling transformer is actually applied in the step one include: voltage stress, current stress, voltage gain, and output power.

Further, in the present invention, the fixed size parameters of the primary side coupling mechanism and the secondary side coupling mechanism in the first step include: the coil comprises a primary side ferrite magnetic core, a secondary side ferrite magnetic core, a primary side DD coil outer contour dimension, a secondary side DD coil outer contour dimension, the diameter of a primary side planar solenoid coil wire, the diameter of a primary side DD coil wire, the diameter of a secondary side planar solenoid coil wire, the diameter of a secondary side DD coil wire, the distance between two parts of the primary side DD coil and the distance between two parts of the secondary side DD coil.

Further, in the present invention, the maximum value of the number of iterations in step two is 5.

Further, in the present invention, the scanning step size of the iteration of the parameter to be optimized in step three includes: coil turn number scanning step Δ N_mAnd the distance between the two parts of the solenoid coil is scanned by a step delta l_m。

Further, in the present invention, the determining the range of the parameter to be optimized in the third step includes:

determining the turn range of a primary side planar solenoid coil, the turn range of a primary side DD coil, the turn range of a secondary side planar solenoid coil, the turn range of a secondary side DD coil, the distance range between two parts of the primary side planar solenoid coil and the distance range between two parts of the secondary side planar solenoid coil;

the method for determining the turn range of the primary side planar solenoid coil, the turn range of the primary side DD coil, the turn range of the secondary side planar solenoid coil and the turn range of the secondary side DD coil is the same;

the method for determining the turn range of the primary side plane solenoid coil comprises the following steps:

when m is equal to 1, the minimum number of turns N of the primary side planar solenoid coil_1-minSet to 1, maximum number of turns N_1-maxAccording to maximum mutual inductance M_{12_max}Setting; when m is not equal to 1, the number of turns of the primary side plane solenoid coil is the minimum number of turns N_1-minIs set to N₁–3×ΔN_m–1Maximum number of turns N_1-maxIs set to N₁+3×ΔN_m–1Wherein, Δ N_m–1Scanning step length for the m-1 th iteration coil turns;

the method for determining the distance range between the two parts of the primary side planar solenoid coil and the distance range between the two parts of the secondary side planar solenoid coil are the same;

the method for determining the distance range between two parts of the primary side planar solenoid coil comprises the following steps:

when m is equal to 1, the minimum distance l between two parts of the primary side plane solenoid coil is set_12x-minSet to 0, maximum spacing l_12x-maxIs set to d_Px–2×l_1x(ii) a When m is not equal to 1, the minimum distance l between two parts of the primary side plane solenoid coil is set_12x-minIs set to l_12x–3×Δl_m–1Maximum distance l_12x-maxIs set to l_12x+3×Δl_m–1Wherein d is_PxIs the length of the primary core, /)_1xLength of primary planar solenoid coil, Deltal_m–1The step size is scanned for the distance between the two parts of the coil for the (m-1) th iteration.

Further, in the present invention, the method for updating the parameters to be optimized in sequence by using the fluctuation minimization principle in the fourth step is:

the method for updating the number of turns of the primary side planar solenoid coil, the number of turns of the primary side DD coil, the number of turns of the secondary side planar solenoid coil, the number of turns of the secondary side DD coil, the distance between two parts of the primary side planar solenoid coil and the distance between two parts of the secondary side planar solenoid coil are the same;

the method for updating the number of turns of the primary side plane solenoid coil comprises the following steps: under the condition of keeping the number of turns of the primary side DD coil, the number of turns of the secondary side planar solenoid coil, the number of turns of the secondary side DD coil, the distance between two parts of the primary side planar solenoid coil and the distance between two parts of the secondary side planar solenoid coil unchanged,

the number of turns of the primary side plane solenoid coil is equal to N in sequence_1-min、N_1-min+ΔN_m、N_1-min+2×ΔN_m、…、N_1-max-ΔN_m、N_1-max；

By means of simulationObtaining the minimum mutual inductance value M of the loosely coupled transformer corresponding to the turn value of each primary side plane solenoid coil_{12_min_op}And maximum mutual inductance value M_{12_max_op}And utilizing a fluctuation coefficient formula of the loosely coupled transformer:

and solving the fluctuation coefficient corresponding to the turn value of each primary side plane solenoid coil, and updating the turn value of the primary side plane solenoid coil to the turn value of the primary side plane solenoid coil corresponding to the minimum fluctuation coefficient.

The existing planar solenoid loose coupling transformer or the DD-shaped loose coupling transformer is sensitive to the deviation of the magnetic field direction, and the deviation resistance performance in the direction is poor. The planar solenoid coil and the DD coil are combined, and different connection modes are adopted on the primary side and the secondary side, so that the anti-offset performance of the DD-PS (the DD coil and the planar solenoid coil are combined) loose coupling transformer in the magnetic field direction is remarkably improved, and the excellent anti-offset performance of the planar solenoid loose coupling transformer and the DD-shaped loose coupling transformer in the vertical magnetic field direction is kept. By adopting the method for determining the parameters of the loosely coupled transformer, the parameters of the loosely coupled transformer can be rapidly determined, and an optimized solution meeting application requirements is obtained. Compared with a planar solenoid loose coupling transformer and a DD-shaped loose coupling transformer, the loose coupling transformer has a slightly lower coupling coefficient when in positive time setting, so that the loose coupling transformer is very suitable for large-offset, medium-and-small-power scenes, such as the fields of consumer electronics, household appliances and the like. When the offset distances are the same, by using the DD-PS loose coupling transformer, the output voltage or current fluctuation of a rectifying circuit of a wireless power transmission system is obviously reduced, and the design difficulty of a rear-stage DC/DC converter is obviously reduced; when the input voltage ranges of the rear-stage DC/DC converters are the same, the DD-PS loose coupling transformer is used, the offset range of a wireless power transmission system is remarkably enlarged, and the degree of freedom of system operation is remarkably improved.

Drawings

FIG. 1 is a schematic structural diagram of a DD-PS strongly anti-offset loosely coupled transformer according to the present invention;

fig. 2 is a schematic diagram of a winding structure of a primary side planar solenoid coil (a), in which a coil 1 and a coil 2 respectively represent two parts of the primary side planar solenoid coil (a);

fig. 3 is a schematic diagram of a winding structure of the secondary side planar solenoid coil (e), in which a coil 5 and a coil 6 respectively represent two parts of the secondary side planar solenoid coil (e);

fig. 4 is a schematic diagram of a winding structure of the primary side DD coil (f), in which coil 3 and coil 4 respectively represent two parts of the primary side DD coil (f);

fig. 5 is a schematic diagram of a winding structure of the secondary side DD coil (d), in which the coil 7 and the coil 8 respectively represent two parts of the secondary side DD coil (d);

FIG. 6 is a schematic diagram of an equivalent circuit of a DD-PS loosely coupled transformer;

FIG. 7 is a parameter M₁₂、M_S1S2、M_S1D2、M_D1S2And M_D1D2A graph of variation with X-direction offset;

FIG. 8 is parameter M₁₂、M_S1S2、M_S1D2、M_D1S2And M_D1D2A variation profile with Y-direction offset;

FIG. 9 is a schematic diagram of an actual wound loosely coupled transformer;

FIG. 10 is simulated and measured M₁₂Graph with offset distance in X and Y directions.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The first embodiment is as follows: the present embodiment is described below with reference to fig. 1, and the DD-PS strong anti-offset loose-coupled transformer in the present embodiment includes a primary side coupling mechanism and a secondary side coupling mechanism; the primary side coupling mechanism and the secondary side coupling mechanism are arranged oppositely;

the primary side coupling mechanism comprises a primary side planar solenoid coil a, a primary side DD coil f and a primary side ferrite magnetic core b;

the primary side ferrite core b is rectangular, and the primary side DD coil f is arranged on the side, close to the secondary side coupling mechanism, of the primary side ferrite core b and is parallel to the primary side ferrite core b;

the primary side planar solenoid coil a is divided into two parts which are wound on the primary side ferrite magnetic core b, and the number of turns of the primary side planar solenoid coil a is the same;

the primary side planar solenoid coil a is connected with the primary side DD coil f in a reverse connection mode;

the secondary coupling mechanism comprises a secondary planar solenoid coil e, a secondary DD coil d and a secondary ferrite core c;

the secondary ferrite core c is rectangular, and the secondary DD coil d is arranged on one side, close to the primary side coupling mechanism, of the secondary ferrite core c and is parallel to the secondary ferrite core c;

the secondary side planar solenoid coil e is wound on the secondary side ferrite magnetic core c in two parts, and the number of turns of the secondary side planar solenoid coil e in the two parts is the same;

the secondary planar solenoid coil e and the secondary DD coil d are connected in a direct connection mode.

Further, in the present embodiment, the winding directions of the two portions of the primary planar solenoid coil a are both perpendicular to the length direction of the primary ferrite core b; the winding directions of the two parts of the secondary planar solenoid coil e are both vertical to the length direction of the secondary ferrite core c.

In the present embodiment, a gap is left between two portions of the primary side planar solenoid coil a, and a gap is also left between two portions of the secondary side planar solenoid coil e.

Further, in the present embodiment, two parts of the primary planar solenoid coil a are symmetrical with respect to the center of the primary ferrite core b; the two parts of the secondary planar solenoid coil e are symmetrical about the center of the secondary ferrite core c.

Further, in the present embodiment, the outer dimensions of the primary side DD coil f and the secondary side DD coil d are equal to the outer dimensions of the primary side magnetic core and the secondary side magnetic core, respectively.

In order to ensure that the same anti-offset performance is achieved in the + X direction and the-X direction, two parts of a primary side planar solenoid coil a are respectively set as a coil 1 and a coil 2, two parts of a primary side DD coil f are respectively set as a coil 3 and a coil 4, two parts of a secondary side planar solenoid coil e are respectively set as a coil 5 and a coil 6, and two parts of a secondary side DD coil d are respectively set as a coil 7 and a coil 8; as shown in fig. 2 to 5; the loosely coupled transformer of the present invention is symmetrical about the XOZ plane (see figure 1),

therefore, the number of turns and the size of the coil 1 and the coil 2 are the same, the number of turns and the size of the coil 3 and the coil 4 are the same, the number of turns and the size of the coil 5 and the coil 6 are the same, and the number of turns and the size of the coil 7 and the coil 8 are the same.

To simplify the design process, the width of each side of the coil 3 is the same, the width of each side of the coil 4 is the same, the width of each side of the coil 7 is the same, and the width of each side of the coil 8 is the same.

For the magnetic core of make full use of, the outer contour size of former limit DD coil f and vice limit DD coil d equals the outer contour size of former limit magnetic core and vice limit magnetic core respectively, promptly: 2l_3x+l_34x＝d_Px，l_3y＝d_Py，2l_7x+l_78x＝d_Sx，l_7y＝d_Sy. The meanings of the relevant parameters are shown in Table 1.

The planar solenoid coil is tightly wrapped around the bobbin. Namely: l_1y＝d_Py+2(d_h+d_NP)，l_5y＝d_Sy+2(d_h+d_NS). The meanings of the relevant parameters are shown in Table 1.

TABLE 1 DD-PS loosely coupled Transformer principal parameters

The DD-PS loose coupling transformer of the invention is different from the traditional loose coupling transformer combining a solenoid coil and a DD coil, and the main differences are as follows: first, the coil connection method is different. The primary side and the secondary side of a traditional loose coupling transformer combined with a solenoid coil and a DD coil are connected in a direct mode, and under the condition of direct alignment or deviation along the direction of a magnetic field, the magnetic fields generated by the solenoid coil and the DD coil are always mutually enhanced, so that the coupling coefficient is high when the direct alignment is carried out, the coupling coefficient is low when the deviation is carried out along the direction of the magnetic field, and the anti-deviation performance is poor. The DD-PS loose coupling transformer adopts a direct connection mode on one side and a reverse connection mode on the other side, magnetic fields generated by the solenoid coil and the DD coil when the direct connection mode is over, the magnetic fields are mutually offset, the coupling coefficient is low, the magnetic fields generated by the solenoid coil and the DD coil are mutually enhanced when the direct connection mode is over, the coupling coefficient is high, and therefore the DD-PS loose coupling transformer is good in anti-offset performance.

Second, the performance behaves differently. The traditional loose coupling transformer combining the solenoid coil and the DD coil is high in coupling coefficient, but weak in anti-offset capacity, and the DD-PS loose coupling transformer is strong in anti-offset capacity.

Finally, the parameter design and optimization methods are different due to the different connection modes and performance.

FIG. 6 is an equivalent circuit of the DD-PS loosely coupled transformer of the invention, L_PS1And L_PS2Self-inductance, L, of primary and secondary planar solenoidal coils, a and e, respectively_DD1And L_DD2Self-inductance, M, of primary side DD-coil f and secondary side DD-coil d, respectively_S1D1Is the mutual inductance between the primary planar solenoid coil a and the primary DD coil f_S2D2Is the mutual inductance between the secondary planar solenoid coil e and the secondary DD coil d, M_S1S2Is the mutual inductance between the primary planar solenoid coil a and the secondary planar solenoid coil e, M_S1D2Is the mutual inductance between the primary planar solenoid coil a and the secondary DD coil d, M_D1S2Is the mutual inductance between the primary DD coil f and the secondary planar solenoid coil e, M_D1D2Is the mutual inductance between the primary side DD coil f and the secondary side DD coil d, L₁And L₂Are respectively primary side loose couplingSelf-inductance, M, of combined and secondary loosely-coupled transformers₁₂Is the mutual inductance, L, of a DD-PS loosely coupled transformer₁And L_PS1、L_DD1、M_S1D1Satisfies the formula (1), L₂And L_PS2、L_DD2、M_S2D2Satisfies the formula (2), M₁₂And M_S1S2、M_S1D2、M_D1S2、M_D1D2Satisfying formula (3). Within a certain offset range, M_S1S2、M_S1D2Greater than 0 and decreasing with increasing offset, M_D1S2、M_D1D2Less than 0 and its absolute value decreases with increasing offset, so that M is within the entire offset range₁₂Hardly changed and excellent in offset resistance.

L₁＝L_PS1+L_DD1+2M_S1D1 (1)

L₂＝L_PS2+L_DD2-2M_S2D2 (2)

M₁₂＝M_S1S2+M_S1D2+M_D1S2+M_D1D2 (3)

Planar solenoidal loosely coupled transformers and DD-shaped loosely coupled transformers are sensitive to shifts in the direction of the magnetic field, in which direction the resistance to shifts is poor. This patent combines together planar solenoid coil and DD coil, through adopting different connected mode at former secondary side, is showing and is improving DD-PS loose coupling transformer in the anti skew performance of magnetic field direction, has remain planar solenoid loose coupling transformer and DD shape loose coupling transformer simultaneously and has just looked the excellent anti skew performance in perpendicular magnetic field direction. By adopting the optimal design method of the loosely coupled transformer, each parameter of the loosely coupled transformer can be quickly determined, and an optimal solution meeting application requirements is obtained. Compared with a planar solenoid loose coupling transformer and a DD-shaped loose coupling transformer, the loose coupling transformer disclosed by the invention has a slightly lower coupling coefficient when in positive time setting, so that the loose coupling transformer is very suitable for large-offset, medium-and-small-power scenes, such as the fields of consumer electronics, household appliances and the like. When the offset distances are the same, by using the DD-PS loose coupling transformer disclosed by the invention, the output voltage or current fluctuation of a rectifying circuit of a wireless power transmission system is obviously reduced, and the design difficulty of a rear-stage DC/DC converter is obviously reduced; when the input voltage ranges of the rear-stage DC/DC converters are the same, the DD-PS loose coupling transformer provided by the invention is used, the offset range of a wireless power transmission system is remarkably increased, and the degree of freedom of system operation is remarkably improved.

The parameter determination method of the anti-offset loose coupling transformer comprises the following steps:

the parameters to be optimized comprise: the number of turns of the primary side planar solenoid coil a, the number of turns of the secondary side planar solenoid coil e, the number of turns of the primary side DD coil f, the number of turns of the secondary side DD coil d, the distance between the two parts of the primary side planar solenoid coil a and the distance between the two parts of the secondary side planar solenoid coil e;

Step five, judging the mutual inductance value M of the iteration loose coupling transformer_{12_m}Whether or not the range [ M ] is satisfied_{12_min},M_{12_max}](ii) a If yes, executing a seventh step, otherwise, executing a sixth step;

step six, utilizing a formula:

sequentially updating the number of turns of the primary planar solenoid coil a and the secondary planar solenoid in the parameters to be optimizedThe number of turns of the tube coil e, the number of turns of the primary side DD coil f and the number of turns of the secondary side DD coil d are calculated, and then the mutual inductance value M of the loose coupling transformer is updated_{12_m}Executing the step seven; where round represents the rounding function, and when i is equal to 1, 3, 5, 7, N_iRespectively showing the number of turns of the primary side planar solenoid coil a, the number of turns of the primary side DD coil f, the number of turns of the secondary side planar solenoid coil e and the number of turns of the secondary side DD coil d;

step seven, judging whether the value of the current iteration number m is equal to the maximum value of the iteration number, if so, recording the distance between two parts of the primary side planar solenoid coil a, the distance between two parts of the secondary side planar solenoid coil e, the number of turns of the primary side planar solenoid coil a, the number of turns of the secondary side planar solenoid coil e, the number of turns of the primary side DD coil f and the number of turns of the secondary side DD coil d which are updated in the step six, and finishing the parameter determination of the loose coupling transformer; otherwise, making the current iteration number m equal to m +1, and returning to execute the step three.

Further, in this embodiment, the parameters of the wireless power transmission system in which the anti-offset loose coupling transformer is actually applied in the first step include: voltage stress, current stress, voltage gain, and output power.

Further, in this embodiment, the fixed size parameters of the primary side coupling mechanism and the secondary side coupling mechanism in the first step include: the size of the primary side ferrite magnetic core b, the size of the secondary side ferrite magnetic core c, the size of the outer contour of the primary side DD coil f, the size of the outer contour of the secondary side DD coil d, the diameter of the wire of the primary side planar solenoid coil a, the diameter of the wire of the primary side DD coil f, the diameter of the wire of the secondary side planar solenoid coil e, the diameter of the wire of the secondary side DD coil d, the distance between two parts of the primary side DD coil f and the distance between two parts of the secondary side DD coil d.

Preferably, in this embodiment, the maximum number of iterations in step two is 5.

Further, in this embodiment, the scan step size of the iteration of the parameter to be optimized in step three includes: coil turn number scanning step Δ N_mAnd the distance between the two parts of the solenoid coil is scanned by a step delta l_m。

Further, in the embodiment, the method for determining the parameter range to be optimized in the third step includes:

determining the turn range of a primary side planar solenoid coil a, the turn range of a primary side DD coil f, the turn range of a secondary side planar solenoid coil e, the turn range of a secondary side DD coil d, the distance range between two parts of the primary side planar solenoid coil a and the distance range between two parts of the secondary side planar solenoid coil e;

the method for determining the turn range of the primary side planar solenoid coil a, the turn range of the primary side DD coil f, the turn range of the secondary side planar solenoid coil e and the turn range of the secondary side DD coil d is the same;

the method for determining the turn number range of the primary side planar solenoid coil a comprises the following steps:

when m is equal to 1, the minimum number of turns N of the primary side plane solenoid coil a_1-minSet to 1, maximum number of turns N_1-maxAccording to maximum mutual inductance M_{12_max}Setting; when m is not equal to 1, the number of turns of the primary side plane solenoid coil a is the minimum number of turns N_1-minIs set to N₁–3×ΔN_m–1Maximum number of turns N_1-maxIs set to N₁+3×ΔN_m–1Wherein, Δ N_m–1Coil turn number scanning step size, N, for the m-1 iteration₁The number of turns of the primary side planar solenoid coil a is a known quantity at this time;

the method for determining the distance range between the two parts of the primary side planar solenoid coil a and the distance range between the two parts of the secondary side planar solenoid coil e is the same;

the method for determining the distance range between two parts of the primary side plane solenoid coil a comprises the following steps:

when m is equal to 1, the minimum distance l between two parts of the primary side plane solenoid coil a is set_12x-minSet to 0, maximum spacing l_12x-maxIs set to d_Px–2×l_1x(ii) a When m is not equal to 1, the minimum distance l between two parts of the primary side plane solenoid coil a is set_12x-minIs set to l_12x–3×Δl_m–1Maximum distance l_12x-maxIs set to l_12x+3×Δl_m–1Which isIn d_PxIs the length of the primary core, /)_1xIs the length of the primary planar solenoid coil a, Deltal_m–1The step is scanned for the distance between the two parts of the coil for the (m-1) th iteration.

Further, in the present embodiment, the method for sequentially updating the parameters to be optimized by using the minimum fluctuation rule in the fourth step is as follows:

the method for updating the number of turns of the primary side planar solenoid coil a, the number of turns of the primary side DD coil f, the number of turns of the secondary side planar solenoid coil e, the number of turns of the secondary side DD coil d, the distance between the two parts of the primary side planar solenoid coil a and the distance between the two parts of the secondary side planar solenoid coil e are the same;

the method for updating the number of turns of the primary side planar solenoid coil a comprises the following steps: under the condition of keeping the f turns of the primary side DD coil, the e turns of the secondary side planar solenoid coil, the d turns of the secondary side DD coil, the distance between the two parts of the primary side planar solenoid coil a and the distance between the two parts of the secondary side planar solenoid coil e unchanged,

the number of turns of the primary side plane solenoid coil a is equal to N in turn_1-min、N_1-min+ΔN_m、N_1-min+2×ΔN_m、…、N_1-max-ΔN_m、N_1-max，

Obtaining the minimum mutual inductance value M of the loosely coupled transformer corresponding to the turn value of each primary side plane solenoid coil a through simulation_{12_min_op}And maximum mutual inductance value M_{12_max_op}And utilizing a fluctuation coefficient formula of the loosely coupled transformer:

and solving the fluctuation coefficient corresponding to the turn value of each primary side plane solenoid coil a, and updating the turn number of the primary side plane solenoid coil a to the turn number of the primary side plane solenoid coil a corresponding to the minimum fluctuation coefficient.

The specific embodiment is as follows:

the first step is as follows: determining DD-PS loose coupling according to constraints such as voltage stress, current stress, voltage gain and output powerObtaining the minimum mutual inductance M through the value range of the mutual inductance of the transformer_{12_min}And maximum mutual inductance M_{12_max}；

Two parts of a primary side planar solenoid coil a are respectively set as a coil 1 and a coil 2, two parts of a primary side DD coil f are respectively set as a coil 3 and a coil 4, two parts of a secondary side planar solenoid coil e are respectively set as a coil 5 and a coil 6, and two parts of a secondary side DD coil d are respectively set as a coil 7 and a coil 8; as shown in fig. 2 to 5;

the second step is that: and determining the sizes of the primary side magnetic core and the secondary side magnetic core of the loose coupling transformer and the size of the outer contour of the DD coil according to the size limit of practical application. To make full use of the space and at the same time avoid short-circuits between the coils 3 and 4 and between the coils 7 and 8 during the simulation, the distance l between the coils 3 and 4 is set_34xAnd the distance l between the coil 7 and the coil 8_78xSet to 2 mm.

The third step: setting an initial value, mainly including the primary Litz wire diameter d_NP(the primary planar solenoid coil a and the primary DD coil f use the same Litz wire), and the secondary Litz wire diameter d_NS(the same Litz wire is used for the secondary planar solenoid coil e and the secondary DD coil d), and the number of turns of coil N is 1₁Coil 3 turns N₃5 turns of coil N₅Coil 7 turns N₇Coil 1 and coil 2 spacing l_12xCoil 5 and coil 6 spacing l_56xIteration number m and maximum iteration number m_max。d_NPAnd d_NSDetermined by the current.

In this embodiment, N₁、N₃、N₅、N₇Initial value is set to 10, l_12xSet to 0.5 × (d)_Px–2×l_1x)，l_56xSet to 0.5 × (d)_Sx–2×l_5x) The number of iterations m is equal to 1, the maximum number of iterations m_maxEqual to 5.

The fourth step: determining turn number scanning step length delta N according to value of iteration number m_m. The basic principle is that the smaller m, Δ N_mThe larger m, the larger Δ N_mThe smaller. Delta N_mIs a positive integer, and m is equal to m_maxWhen is Δ N_mShould be equal to 1.

The fifth step: determining the range of the number of turns of the coil 1 according to the value of the iteration number m: when m is equal to 1, the minimum number of turns N of the coil 1 is set_1-minSet to 1, maximum number of turns N_1-maxAccording to the maximum mutual inductance M_{12_max}Setting; when m is not equal to 1, the minimum number of turns N of the coil 1 is set_1-minIs set to N₁–3×ΔN_m–1Maximum number of turns N_1-maxIs set to N₁+3×ΔN_m–1. In N₁Based on the current value, in Δ N_mStep size of scanning N in two directions of increasing and decreasing₁And updating N according to the principle of minimum fluctuation₁The value of (c). In the shifting process, the ripple factor of the loosely coupled transformer is defined as:

wherein M is_{12_min_op}And M_{12_max_op}Respectively representing the maximum and minimum mutual inductance of the loosely coupled transformer over the desired offset range for the set of parameters. The larger K, the smaller the fluctuation.

And a sixth step: determining the turn number range of the coil 3 according to the value of the iteration number m: when m is equal to 1, the minimum number of turns N of the coil 3 is set_3-minSet to 1, maximum number of turns N_3-maxAccording to maximum mutual inductance M_{12_max}Setting; when m is not equal to 1, the minimum number of turns N of the coil 3 is set_3-minIs set to N₃–3×ΔN_m–1Maximum number of turns N_3-maxIs set to N₁+3×ΔN_m–1. In N₃Based on the current value, in Δ N_mStep size of scanning N in two directions of increasing and decreasing₃And updating N according to the principle of minimum fluctuation₃The value of (c).

The seventh step: determining the turn range of the coil 5 according to the value of the iteration number m, and when m is equal to 1, determining the minimum turn number N of the coil 5_5-minSet to 1, maximum number of turns N_5-maxAccording to maximum mutual inductance M_{12_max}Setting; when m is not equal to 1, the minimum number of turns N of the coil 5 is set_5-minIs set to N₅–3×ΔN_m–1Maximum number of turns N_5-maxIs set to N₅+3×ΔN_m–1. In N₅Based on the current value, in Δ N_mStep size of scanning N in two directions of increasing and decreasing₅And updating N according to the principle of minimum fluctuation₅The value of (c).

Eighth step: determining the range of the number of turns of the coil 7 according to the value of the iteration number m: when m is equal to 1, the minimum number of turns N of the coil 7 is set_7-minSet to 1, maximum number of turns N_7-maxAccording to the maximum mutual inductance M_{12_max}Setting; when m is not equal to 1, the minimum number of turns N of the coil 7 is set_7-minIs set to N₇–3×ΔN_m–1Maximum number of turns N_7-maxIs set to N₇+3×ΔN_m–1. At N₇Based on the current value, in Δ N_mStep size of scanning N in two directions of increasing and decreasing₇And updating N according to the principle of minimum fluctuation₇The value of (c).

The ninth step: determining a solenoid coil spacing scan step Δ l from a value of the number of iterations m_m: the basic principle is that the smaller m, Δ l_mThe larger, the larger m, Δ l_mThe smaller. Δ l_mIs a positive integer and has the unit of mm.

The tenth step: determining the distance l between the coil 1 and the coil 2 according to the value of the iteration number m_12xThe range of (A): when m is equal to 1, the minimum distance l between the coil 1 and the coil 2 is set_12x-minSet to 0, maximum spacing l_12x-maxIs set to d_Px–2×l_1x(ii) a When m is not equal to 1, the coil 1 and the coil 2 are separated by a minimum distance l_12x-minIs set to l_12x–3×Δl_m–1Maximum distance l_12x-maxIs set to l_12x+3×Δl_m–1. At l_12xBased on the current value, in Δ l_mStep length of (1) scanning in two directions_12xAnd updating l according to the principle of minimum fluctuation_12xThe value of (c).

The eleventh step: determining the distance l between the coil 5 and the coil 6 according to the value of the iteration number m_56xIn (c) is used. When m is equal to 1, the coil 5 and the coil 6 are separated by a minimum distance l_56x-minSet to 0, maximum spacing l_56x-maxIs set to d_Sx–2×l_5x(ii) a When m is not equal to 1, willMinimum spacing l of coils 5 and 6_56x-minIs set to l_56x–3×Δl_m–1Maximum distance l_56x-maxIs set to l_56x+3×Δl_m–1. In l_56xBased on the current value, in Δ l_mStep length of (1) scanning in two directions_56xAnd updating l according to the principle of minimum fluctuation_56xThe value of (c).

The twelfth step: according to 1 turn number N of coil₁Coil 3 turns N₃5 turns of coil N₅Coil 7 turns N₇Coil 1 and coil 2 spacing l_12xCoil 5 and coil 6 spacing l_56xThe mutual inductance value M of the loosely coupled transformer is obtained through simulation_{12_m}If it is at [ M_{12_min},M_{12_max}]In the range, jump to the thirteenth step, otherwise, update the number of turns of coil 1, coil 3, coil 5, coil 7 according to formula (5).

The thirteenth step: if the iteration number m is larger than the maximum iteration number m_maxAnd ending optimization, otherwise, jumping to the fourth step.

According to the optimal design method of the loose coupling transformer, the optimized DD-PS loose coupling transformer is obtained, and the main parameters of the optimized DD-PS loose coupling transformer are shown in the table 2.

TABLE 2 optimized DD-PS loosely coupled Transformer principal parameters

According to the table 2, a 3-dimensional simulation model is built in ANSYS Maxwell, and M is shown in FIG. 7₁₂、M_S1S2、M_S1D2、M_D1S2And M_D1D2The curve shifts with the X direction. When the offset distance in the X direction does not exceed 150mm, M_S1S2、M_S1D2Constantly greater than 0, the value of which decreases with increasing offset distance, M_D1S2、M_D1D2Constantly less than 0, whichThe absolute value decreases with increasing offset, so that M decreases over the entire offset range₁₂The variation is very small and the loose coupling transformer has excellent anti-offset performance in the X direction. FIG. 8 shows M₁₂、M_S1S2、M_S1D2、M_D1S2And M_D1D2Along with the Y-direction deviation change curve, when the Y-direction deviation distance is not more than 80mm, the variation trend of each mutual inductance along with the deviation is similar to that of the X-direction deviation, and when the Y-direction deviation distance is between 80mm and 110mm, M is_D1D2Changes from negative to positive and increases with increasing offset, and within the whole offset range, M₁₂The loose coupling transformer has almost no change, and has good anti-offset performance in the Y direction.

A DD-PS loosely coupled transformer was actually wound according to table 2, as shown in fig. 9. The wound loosely coupled transformer was tested and the test results are shown in fig. 10. M when the X-direction deviation is between 0mm and 140mm₁₂The range of M is 31.6 muH-33.4 muH, when the ratio of the offset distance in the X direction to the size of the loose coupling transformer in the X direction is not more than 67.6 percent, M is₁₂Only 5.8% change; m is 0 mm-110 mm in Y direction₁₂The range of M is 31.4 muH-33.6 muH, when the ratio of the offset distance in the Y direction to the dimension of the loose coupling transformer in the Y direction is not more than 44 percent, M is₁₂Only 5.0% change. For comparison, the simulation result is also shown in fig. 10, and the actually measured mutual inductance value and the simulated mutual inductance value have completely the same trend along with the change of the X direction and the Y square offset, and are very close in value.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that various dependent claims and the features described herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.

Claims

1. The method is realized based on a DD-PS strong anti-offset loose coupling transformer and is characterized in that the DD-PS strong anti-offset loose coupling transformer comprises a primary side coupling mechanism and a secondary side coupling mechanism; the primary side coupling mechanism and the secondary side coupling mechanism are arranged oppositely;

the primary side coupling mechanism comprises a primary side planar solenoid coil (a), a primary side DD coil (f) and a primary side ferrite magnetic core (b);

the primary side ferrite core (b) is rectangular, and the primary side DD coil (f) is arranged on the side, close to the secondary side coupling mechanism, of the primary side ferrite core (b) and is parallel to the primary side ferrite core (b);

the primary side planar solenoid coil (a) is divided into two parts and wound on the primary side ferrite magnetic core (b), and the number of turns of the two parts of the primary side planar solenoid coil (a) is the same;

the primary side planar solenoid coil (a) is connected with the primary side DD coil (f) in a reverse connection mode;

the secondary side coupling mechanism comprises a secondary side planar solenoid coil (e), a secondary side DD coil (d) and a secondary side ferrite magnetic core (c);

the secondary ferrite core (c) is rectangular, and the secondary DD coil (d) is arranged on one side, close to the primary side coupling mechanism, of the secondary ferrite core (c) and is parallel to the secondary ferrite core (c);

the secondary side planar solenoid coil (e) is wound on the secondary side ferrite magnetic core (c) in two parts, and the number of turns of the secondary side planar solenoid coil (e) in the two parts is the same;

the secondary planar solenoid coil (e) is connected with the secondary DD coil (d) in a direct connection mode;

the parameters to be optimized comprise: the number of turns of the primary side planar solenoid coil (a), the number of turns of the secondary side planar solenoid coil (e), the number of turns of the primary side DD coil (f), the number of turns of the secondary side DD coil (d), the distance between the two parts of the primary side planar solenoid coil (a) and the distance between the two parts of the secondary side planar solenoid coil (e);

Step five, judging the mutual inductance value M of the iteration loose coupling transformer_{12_m}Whether the range [ M ] is satisfied_{12_min},M_{12_max}](ii) a If yes, executing a seventh step, otherwise, executing a sixth step; wherein M is_{12_max}Is the maximum mutual inductance value, M_{12_min}Is the minimum mutual inductance value;

step six, utilizing a formula:

sequentially updating the number of turns of the primary planar solenoid coil (a), the number of turns of the secondary planar solenoid coil (e), the number of turns of the primary DD coil (f) and the number of turns of the secondary DD coil (d) in the parameters to be optimized, and then updating the mutual inductance value M of the loosely coupled transformer_{12_m}Executing the step seven; where round represents the rounding function, and when i is equal to 1, 3, 5, 7, N_iRespectively showing the number of turns of the primary side planar solenoid coil (a), the number of turns of the primary side DD coil (f), the number of turns of the secondary side planar solenoid coil (e) and the number of turns of the secondary side DD coil (d);

step seven, judging whether the value of the current iteration number m is equal to the maximum value of the iteration number, if so, recording the updated parameters to be optimized updated in the step four, and finishing the parameter determination of the loosely coupled transformer; otherwise, making the current iteration number m equal to m +1, and returning to execute the step three.

2. The method for determining parameters of an anti-migration loose-coupling transformer according to claim 1, wherein the winding direction of the two parts of the primary planar solenoid coil (a) is perpendicular to the length direction of the primary ferrite core (b); the winding directions of the two parts of the secondary plane solenoid coil (e) are both vertical to the length direction of the secondary ferrite core (c).

3. The method for determining parameters of an anti-migration loose-coupling transformer according to claim 2, wherein the two parts of the primary planar solenoid coil (a) are symmetrical with respect to the center of the primary ferrite core (b); the two parts of the secondary planar solenoid coil (e) are symmetrical with respect to the center of the secondary ferrite core (c).

4. The method of claim 3, wherein the primary side DD coil (f) and the secondary side DD coil (d) have outer dimensions equal to the outer dimensions of the primary side core and the secondary side core, respectively.

5. The method for determining parameters of an anti-offset loosely-coupled transformer according to claim 1, wherein the parameters of the wireless power transmission system to which the anti-offset loosely-coupled transformer is actually applied in step one comprise: voltage stress, current stress, voltage gain, and output power.

6. The method of claim 1, wherein the parameters of the primary coupling mechanism and the secondary coupling mechanism with fixed dimensions in the first step comprise: the size of the primary side ferrite magnetic core (b), the size of the secondary side ferrite magnetic core (c), the external size of the primary side DD coil (f), the external size of the secondary side DD coil (d), the diameter of the wire of the primary side planar solenoid coil (a), the diameter of the wire of the primary side DD coil (f), the diameter of the wire of the secondary side planar solenoid coil (e), the diameter of the wire of the secondary side DD coil (d), the distance between two parts of the primary side DD coil (f) and the distance between two parts of the secondary side DD coil (d).

7. The method for determining parameters of an anti-migration loose-coupling transformer according to claim 1, wherein the maximum number of iterations in step two is 5.

8. The method of claim 1, wherein the step size of the scanning of the iteration of the step three for which the parameter is to be optimized comprises: coil turn number scanning step Δ N_mAnd the distance between the two parts of the solenoid coil is scanned by a step delta l_m。

9. The method for determining parameters of an anti-offset loosely coupled transformer according to claim 1, wherein the step three for determining the parameter range to be optimized comprises:

determining the turn range of a primary side planar solenoid coil (a), the turn range of a primary side DD coil (f), the turn range of a secondary side planar solenoid coil (e), the turn range of a secondary side DD coil (d), the distance range between two parts of the primary side planar solenoid coil (a) and the distance range between two parts of the secondary side planar solenoid coil (e);

the method for determining the turn range of the primary side planar solenoid coil (a), the turn range of the primary side DD coil (f), the turn range of the secondary side planar solenoid coil (e) and the turn range of the secondary side DD coil (d) is the same;

the method for determining the turn range of the primary side planar solenoid coil (a) comprises the following steps:

when m is equal to 1, the primary side plane solenoid coil (a) is turned for the minimum number of turns N_1-minSet to 1, maximum number of turns N_1-maxAccording to maximum mutual inductance M_{12_max}Setting; when m is not equal to 1, the number of turns of the primary side plane solenoid coil (a) is minimum, and N is the minimum number of turns_1-minIs set to N₁–3×ΔN_m–1Maximum number of turns N_1-maxIs set to N₁+3×ΔN_m–1Wherein, Δ N_m–1Scanning step length for the m-1 th iteration coil turns; n is a radical of₁Primary side planar solenoid lineThe number of turns of the loop (a);

the method for determining the distance range between the two parts of the primary side plane solenoid coil (a) and the distance range between the two parts of the secondary side plane solenoid coil (e) is the same;

the method for determining the distance range between the two parts of the primary side planar solenoid coil (a) comprises the following steps:

when m is equal to 1, the minimum distance l between two parts of the primary side plane solenoid coil (a)_12x-minSet to 0, maximum spacing l_12x-maxIs set to d_Px–2×l_1x(ii) a When m is not equal to 1, the minimum distance l between two parts of the primary side plane solenoid coil (a)_12x-minIs set to l_12x–3×Δl_m–1Maximum distance l_12x-maxIs set to l_12x+3×Δl_m–1Wherein d is_PxIs the length of the primary core, /)_1xIs the length of the primary planar solenoid coil (a), Deltal_m–1The step is scanned for the distance between the two parts of the coil for the (m-1) th iteration.

10. The method for determining parameters of the anti-migration loose-coupling transformer according to claim 9, wherein the method for sequentially updating the parameters to be optimized by using the principle of minimum fluctuation in the fourth step comprises:

the method for updating the number of turns of the primary side planar solenoid coil (a), the number of turns of the primary side DD coil (f), the number of turns of the secondary side planar solenoid coil (e), the number of turns of the secondary side DD coil (d), the distance between the two parts of the primary side planar solenoid coil (a) and the distance between the two parts of the secondary side planar solenoid coil (e) is the same;

the method for updating the number of turns of the primary side planar solenoid coil (a) comprises the following steps: under the condition of keeping the number of turns of the primary side DD coil (f), the number of turns of the secondary side planar solenoid coil (e), the number of turns of the secondary side DD coil (d), the distance between the two parts of the primary side planar solenoid coil (a) and the distance between the two parts of the secondary side planar solenoid coil (e) unchanged,

the number of turns of the primary side plane solenoid coil (a) is equal to N in sequence_1-min、N_1-min+ΔN_m、N_1-min+2×ΔN_m、…、N_1-max-ΔN_m、N_1-max；

Obtaining the minimum mutual inductance value M of the loosely coupled transformer corresponding to the turn number value of each primary side plane solenoid coil (a) through simulation_{12_min_op}And maximum mutual inductance value M_{12_max_op}And utilizing a fluctuation coefficient formula of the loosely coupled transformer:

and (3) solving the fluctuation coefficient corresponding to the turn value of each primary side plane solenoid coil (a), and updating the turn value of the primary side plane solenoid coil (a) to the turn value of the primary side plane solenoid coil (a) corresponding to the minimum fluctuation coefficient.