CN112202251B

CN112202251B - Compensation parameter design method of wireless power transmission circuit capable of self-adapting and full tuning

Info

Publication number: CN112202251B
Application number: CN202011400632.9A
Authority: CN
Inventors: 柯光洁; 陈乾宏; 高伟; 陈俊杰; 徐立刚; 温振霖; 任小永; 张之梁
Original assignee: Jiangsu Zhanxin Semiconductor Technology Co ltd; Nanjing University of Aeronautics and Astronautics
Current assignee: Jiangsu Zhanxin Semiconductor Technology Co ltd; Nanjing University of Aeronautics and Astronautics
Priority date: 2020-12-04
Filing date: 2020-12-04
Publication date: 2021-03-02
Anticipated expiration: 2040-12-04
Also published as: CN112202251A

Abstract

The invention discloses a parameter design method of a wireless power transmission circuit capable of self-adapting and full tuning, belonging to the technical field of wireless power transmission. The applicable wireless power transmission circuit comprises an excitation source, a primary side compensation network and a primary side coil which are connected in sequenceL ₁And a receiving coilL ₂A secondary side compensation network, a load, and a tuning coilL ₃And an additional compensation network. The compensation method overcomes the defects that the parameters of the resonance element in the conventional compensation mode are related to the mutual inductance of the primary side and the secondary side of the magnetic coupler, and a system can deviate from a complete compensation point and detune when the relative position of the primary side and the secondary side changes, can realize constant-voltage or constant-current output irrelevant to load change under the variable coupling working condition without a complex control strategy, and simultaneously realizes input zero reactive power in the variable coupling and load range.

Description

Compensation parameter design method of wireless power transmission circuit capable of self-adapting and full tuning

Technical Field

The invention belongs to the field of wireless charging, and relates to a compensation parameter design method of a wireless power transmission circuit capable of self-adapting and full tuning.

Background

The inductive wireless power transmission technology is used for safely and reliably transmitting power to electric equipment in a non-contact mode through a magnetic field, and is widely applied to the fields of electric automobiles, AGV trolleys, built-in medical devices, portable electronic products and the like. The core component in the wireless electric energy transmission system is a magnetic coupler with separated primary and secondary sides, and the magnetic coupler has larger leakage inductance, smaller excitation inductance and low transmission efficiency and active power due to larger air gap. Therefore, a multi-element resonant converter is required to be adopted in the wireless electric energy transmission system, a compensation topology is introduced, leakage inductance and excitation inductance are compensated, voltage gain and power transmission capacity are improved, circulating current loss is reduced, and conversion efficiency is improved.

Usually, a compensation element (L、C) The parameters are designed according to the parameters of the magnetic coupler at the complete compensation position and the electrical requirements of the system, but for the compensation topology in which partial resonance parameters are directly related to the mutual inductance parameters of the primary side and the secondary side of the magnetic coupler, after the complete compensation position is deviated due to variable air gaps or dislocation between the primary side and the secondary side, if the size of a compensation element cannot be adjusted in time, the advantages of low inverter volt-ampere capacity, low current stress, soft switching, constant voltage/constant current output and the like during complete compensation can be lost, and the system can be unstable or even out of control in serious cases. Taking the primary side series and secondary side parallel compensation (referred to as series/parallel compensation for short) as an example, fig. 1 is a schematic diagram of a conventional series/parallel compensation resonant converter, and documents y.h. Sohn, b.h. in order to obtain constant voltage output.Choi, and etc. General unified analyses of two-capacitor inductive power transfer systems: equivalence of current-source SS and SP compensations [J]IEEE Trans power electron, 30(11), 6030-C ₁Compensation capacitor connected in parallel with secondary sideC ₂The parameter values of (2):

wherein the content of the first and second substances,L ₁、L ₂、kself-inductance of primary and secondary windings of respective magnetic couplerAnd a coupling coefficient, omega being the resonance frequency, at which the converter operates, the series/parallel compensated resonant converter being fully compensated, with a corresponding output voltage gain and input impedance of

Wherein the content of the first and second substances,Mis the mutual inductance between the primary and secondary windings of the magnetic coupler,R _Efor the ac equivalent load resistance of the converter, it can be seen that at the fully compensated frequency point, the series/parallel compensated non-contact resonant converter has:

a constant voltage output independent of the load,

the pure-resistance input impedance has the advantages of realizing zero reactive input, reducing reactive circulation caused by larger leakage inductance of the loosely-coupled transformer in the system, reducing stress of devices and being beneficial to improving the efficiency of the system. But as can be readily seen from equation (1),C ₁value of (d) and coupling coefficient between primary and secondary windings of a magnetic couplerkIn direct connection, when the coupling coefficient changes, if the compensation capacitance does not change, the converter will operate in a non-complete compensation mode, and deviate from the initial resonance state, and the converter will no longer have the above characteristics.

In order to solve the problem, a conventional solution is to introduce a dynamic tuning circuit, and dynamically adjust the size of the resonant element according to the change of mutual inductance, so that the circuit always works in a resonant state, such as introducing a switched capacitor array, a phase-controlled inductor/capacitor, active impedance adjustment, and the like, but the dynamic tuning circuit needs to sample voltage, current amplitude or phase information in the circuit, and needs to additionally add a power control switch tube and a corresponding driving circuit, thereby greatly increasing the difficulty and complexity of system control.

On the basis of not introducing a complex control strategy, obtaining a wireless power transmission topology capable of realizing self-tuning under a dislocation working condition becomes an important design direction.

Disclosure of Invention

The invention aims to overcome the defects that the parameters of a resonant element are related to the mutual inductance of an original side and a secondary side of a magnetic coupler in the conventional compensation mode, and a system deviates from a complete compensation point and is detuned when the relative position of the original side and the secondary side changes, and provides a method for designing the parameters of a compensation network of a wireless power transmission circuit capable of adaptively tuning.

The object of the invention is achieved by the following embodiments:

a method for designing compensation parameters of a wireless power transmission device capable of self-adapting and full tuning is suitable for a wireless power transmission circuit comprising an excitation source, a primary side compensation network and a primary side coilL ₁Secondary side coilL ₂Secondary side compensation network, load, and tuned coilL ₃And a tuning unit consisting of an additional compensation network; the tuning unit is arranged at the side of the secondary side, and the coil is tunedL ₃And secondary windingL ₂A common secondary side magnetic core; or the tuning unit is arranged at the primary side, and the coil is tunedL ₃And a primary coilL ₁A common primary side magnetic core; tuning coilL ₃And secondary windingL ₂Has a coupling coefficient ofk ₂₃Primary side coilL ₁And secondary windingL ₂Has a coupling coefficient ofk ₁₂Primary side coilL ₁And tuning coilL ₃Has a coupling coefficient ofk ₁₃；

The parameter design steps of the tuning unit are as follows:

step 1: transforming the positions between the original and secondary sides to obtain the coupling coefficients under various conditionsk ₂₃Coupling coefficient ofk ₁₂Coupling coefficient ofk ₁₃A value of (d);

step 2: fitting the obtained coupling coefficient by using a linear function to obtain a fitting function;

for the case where the tuning unit is set on the secondary side, the coupling coefficient in each case obtained in step 1 is setk ₁₃Value and coupling coefficientk ₁₂Fitting the values to obtain a fitting function

WhereinbIs a proportionality coefficient;

or, for the case that the tuning unit is arranged on the primary side, the coupling coefficients obtained in the step 1 under various conditions are comparedk ₂₃Value and coupling coefficientk ₁₂Fitting the values to obtain a fitting function

WhereinaIs a proportionality coefficient;

and step 3: designing reactance of additional compensation networkZ _xcThe following expression is satisfied:

for the case where the tuning unit is arranged on the secondary side,

for the case where the tuning unit is placed on the primary side,

wherein the content of the first and second substances, L ₃in order to tune the self-inductance of the coil,ωfor the designed resonant frequency, lambda is a constant coefficient, and the value of lambda is determined by the structures of the primary side compensation network and the secondary side compensation network.

Further, the tuning unit is placed on the secondary side, and the tuning coil and the secondary coil are mutually decoupled; alternatively, the tuning unit is placed on the primary side, and the tuning coil and the primary coil are decoupled from each other.

Further parameters were designed as follows:

a) the primary side compensation network adopts a series capacitance compensation structure and a compensation capacitorC _1sThe primary coil is connected in series, and the parameter calculation formula is as follows:

whereinL ₁Is a self-inductance of the primary coil,ωa designed resonant frequency;

b) the secondary side compensation network omits or adopts a parallel capacitance compensation structure;

for the condition that the secondary side compensation network adopts a parallel capacitance compensation structure, the compensation capacitorC _2pAnd secondary windingL ₂Parallel connection, the parameter calculation formula is as follows:

whereinL ₂The self-inductance of the secondary side coil is realized,ωin order to be at the designed resonant frequency,k ₂₃for tuning coilsL ₃And secondary windingL ₂The coupling coefficient between the two components is,bis a proportionality coefficient;

c) the tuning unit is placed on the secondary side.

Further parameters were designed as follows:

a) the primary side compensation network adopts a parallel capacitance compensation structure and a compensation capacitorC _1pThe primary coil is connected in parallel, and the parameter calculation formula is as follows:

whereinL ₁Is a self-inductance of the primary coil,ωin order to be at the designed resonant frequency,k ₁₃for tuning coilsL ₃And a primary coilL ₁The coupling coefficient between the two components is,ais a proportionality coefficient;

b) the tuning unit is placed on the primary side, and in the parameter design step 3, the constant coefficient lambda takes the value of 1;

c) the secondary side compensation network adopts a series capacitance compensation structure, or an LCL type compensation structure, or an LCC type compensation structure;

for the condition that the secondary side compensation network adopts a series capacitance compensation structure, the compensation capacitorC _2sAnd secondary windingL ₂Series connected, compensating capacitorsC _2sThe calculation formula is as follows:

whereinL ₂The self-inductance of the secondary side coil is realized,ωa designed resonant frequency;

for the case that the secondary compensation network adopts LCL compensation structure, the compensation network comprises compensation inductanceL _{f_2}And compensation capacitorC _{f_2}Secondary side coilL ₂Compensating inductanceL _{f_2}A compensation capacitor connected with the load in sequenceC _{f_2}Connected in parallel to the secondary coilL ₂The compensation parameter design satisfies the following requirements:

for the case that the secondary compensation network adopts LCC compensation structure, the compensation network comprises compensation inductanceL _{f_2}A first compensation capacitorC _{f_21}And a second compensation capacitorC _{f_22}Secondary side coilL ₂A second compensation capacitorC _{f_22}Compensating inductanceL _{f_2}A first compensation capacitor connected with the load in sequenceC _{f_21}Connected in parallel to the secondary coilL ₂And a second compensation capacitorC _{f_22}And at the two ends of the serial branch, the compensation parameter design meets the following requirements:

wherein, in the step (A),L ₂the self-inductance of the secondary side coil is realized,ωto design forThe resonant frequency of (c).

Further parameters were designed as follows:

a) the tuning unit is placed on the primary side, a primary compensation network is omitted, and in the parameter design step 3, the constant coefficient lambda is 1;

b) the secondary side compensation network adopts a series capacitance compensation structure and compensation capacitanceC _2sAnd secondary windingL ₂The parameters are calculated by the following formula:

whereinL ₂The self-inductance of the secondary side coil is realized,ωthe designed resonant frequency.

Further parameters were designed as follows:

a) the primary side compensation network adopts an LCL type compensation structure and comprises a compensation inductorL _{f_1}And compensation capacitorC _{f_1}Excitation source, compensation inductanceL _{f_1}And a primary coilL ₁Sequentially connected, compensating capacitorsC _{f_1}Connected in parallel to the primary coilL ₁Two-terminal, compensating inductanceL _{f_1}And compensation capacitorC _{f_1}The parameter design satisfies the following conditions:

whereinL ₁Is a self-inductance of the primary coil,ωfor designed resonant frequency

b) The tuning unit is placed on the primary side, and in the parameter design step 3, the constant coefficient lambda is taken as

WhereinL ₁Is a self-inductance of the primary coil,L _{f_1}compensating the inductance for the primary side;

c) the secondary side compensation network adopts a series capacitance compensation structure, or an LCL compensation structure, or an LCC compensation structure;

wherein, in the step (A),L ₂the self-inductance of the secondary side coil is realized,ωthe designed resonant frequency.

Further parameters were designed as follows:

a) the primary side compensation network adopts an LCC type compensation structure and comprises a primary side compensation inductorL _{f_1}First compensation capacitor on primary sideC _{f_11}Primary side second compensation capacitorC _{f_12}Primary side compensation inductanceL _{f_1}Primary side second compensation capacitorC _{f_12}And a primary coilL ₁Sequentially connected first compensation capacitors on the primary sideC _{f_11}Connected in parallel to the primary coilL ₁Second compensation capacitor with primary sideC _{f_12}Primary side compensation inductance at two ends of series branchL _{f_1}First compensation capacitor on primary sideC _{f_11}Second compensation capacitor with primary sideC _{f_12}The parameter design satisfies the following conditions:

b) the tuning unit is placed on the primary side, and in the parameter design step 3, the constant coefficient lambda takes the value as follows:

whereinL ₁Is a self-inductance of the primary coil,ωin order to be at the designed resonant frequency,L _{f_1}compensates the inductance for the primary side,C _{f_12}A primary side second compensation capacitor;

whereinL ₂The self-inductance of the secondary side coil is realized,ωin order to be at the designed resonant frequency,

Further, the excitation source is an alternating current voltage source, or an equivalent alternating current voltage source composed of a direct current source, an inverter and a compensation network.

Furthermore, the excitation source is an alternating current source, or an equivalent alternating current source composed of a direct current source, an inverter and a compensation network;

further, the load also adopts a rectifier bridge and an electric load which are connected with each other.

Compared with the prior art, the invention has the following advantages:

1. the existing series-parallel connection, parallel-series connection,LCL/P、P/LCLWhen the compensation topology is used for realizing constant voltage or constant current output irrelevant to load, the compensation network parameters are relevant to the coupling coefficient of the magnetic coupler, and when the primary side and the secondary side of the transformer generate air gap change and dislocation working conditions, a system deviates from a complete compensation point and a circuit is detuned. The invention overcomes the defect that the system can deviate and detune when the relative position of the primary side and the secondary side changes in the conventional compensation mode, wherein the position change can be the change of transmission distance, translation or rotation in the horizontal direction or the position change in space.

2. According to the adaptive tuning wireless power transmission circuit and the compensation network parameter design method, by designing the compensation parameter value, the parameters of the resonance element are independent of the position change of the primary side and the secondary side of the magnetic coupler and are not easy to detune, the constant voltage or constant current output independent of the load change can be realized under the variable coupling working condition without a complex control strategy, and the input zero reactive power is realized in the variable coupling and load range.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention.

Fig. 1 is a prior art primary side series secondary side parallel compensation circuit topology.

Fig. 2 is a topology of an adaptive full-tunable wireless power transmission circuit according to a first embodiment.

Fig. 3 is an equivalent circuit diagram of a first embodiment of the invention.

Fig. 4 is a topology of an adaptive full-tunable wireless power transmission circuit according to a second embodiment of the present invention.

Fig. 5 is an equivalent circuit diagram of fig. 4.

Fig. 6 shows a topology of an adaptive full-tunable wireless power transmission circuit according to a third embodiment of the present invention.

Fig. 7 is an equivalent circuit diagram of fig. 6.

Fig. 8 is an adaptive full-tunable wireless power transmission circuit topology of the fourth embodiment.

Fig. 9 is an adaptive full-tunable wireless power transmission circuit topology of the fifth embodiment.

Fig. 10 is an adaptive full-tunable wireless power transmission circuit topology of the sixth embodiment.

Fig. 11 is an adaptive full-tunable wireless power transmission circuit topology of the seventh embodiment.

Fig. 12 is an adaptive fully tunable wireless power transmission circuit topology of embodiment eight.

Fig. 13 is an adaptive full-tunable wireless power transmission circuit topology of the ninth embodiment.

Fig. 14 is an adaptive fully tunable wireless power transfer circuit topology of an embodiment ten.

Fig. 15 is an adaptive fully tunable wireless power transmission circuit topology of embodiment eleven.

Fig. 16 is an adaptive fully tunable wireless power transfer circuit topology of embodiment twelve.

Fig. 17 is an adaptive fully tunable wireless power transmission circuit topology of the thirteenth embodiment.

Fig. 18 is an adaptive fully tunable wireless power transmission circuit topology of the fourteenth embodiment.

FIG. 19 is a measurement of the coupling coefficient of a magnetic coupling device used in the present invention.

FIG. 20 is a result of a coupling coefficient fit for a magnetic coupling device used in the present invention.

FIG. 21 is a simulation plot of open loop gain and input impedance angle at the compensation position for an embodiment of the present invention.

FIG. 22 is a simulation of open loop gain and input impedance angle for a varying air gap in accordance with an embodiment of the present invention.

Fig. 23 is a simulation plot of open loop gain and input impedance angle at the compensation position for a prior art series/parallel compensation topology.

Fig. 24 is a simulation plot of open loop gain and input impedance angle for a variable air gap for a prior art series/parallel compensation topology.

FIG. 25 is a graph of simulated input impedance angles for different coupling coefficients according to an embodiment of the present invention.

Main symbol names in the figure:L ₁-the primary power transmitting coil is,L ₂-a secondary side power receiving coil,L ₃-the tuning coil is arranged to be tuned,M ₁₂——L ₁andL ₂the mutual inductance between the two coils is changed,M ₁₃——L ₁andL ₃the mutual inductance between the two coils is changed,M ₂₃——L ₂andL ₃the mutual inductance between the two coils is changed,k ₁₂——L ₁andL ₂the coefficient of coupling between the two elements,k ₁₃——L ₁andL ₃the coefficient of coupling between the two elements,k ₂₃——L ₂andL ₃the coefficient of coupling between the two elements,C _1s-the primary side is connected in series with a compensation capacitor,C _2pthe secondary side is connected with a compensation capacitor in parallel,R _E-a fundamental wave equivalent load resistance,C ₃-an additional compensation capacitance of the tuning unit, L _2mthe primary winding of the additional coupled inductor is self-inductive,L _3m-a secondary winding of an additional coupled inductor,M _m——L _2mandL _3mthe mutual inductance between the two coils is changed,C _m-the decoupling of the capacitance in the first phase,C _2sthe secondary side is connected in series with a compensation capacitor,C_ _1fthe primary coil in the LCL compensation network is connected with the compensation capacitor in parallel,L_ _1f-the primary side compensation inductance is,C_ _2fthe secondary side of the LCL compensation network is connected with the compensation capacitor in parallel,L_ _2f-the secondary side compensates for the inductance,C_ _2f1the secondary side of the LCC compensation network is connected with a compensation capacitor in series,C_ _2f2the secondary side of the LCC compensation network is connected with the compensation capacitor in parallel,C_ _1f1-the primary side of the LCC compensation network is connected with a compensation capacitor in parallel,C_ _1f2-a primary side series compensation capacitor in the LCC compensation network,v ₁-the alternating-current input voltage is,v ₂-the output voltage of the alternating current is,i ₁-the alternating current is input to the power converter,i ₂-the output current of the alternating current is,i _1Lflowing through the primary coilL ₁The current of (a) is measured,i _2Lflowing through the primary coilL ₂The current of (a) is measured,i ₃-flowing through the tuning coilL ₃The current of (2).

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The invention provides a method for designing compensation parameters of a wireless power transmission device capable of realizing self-adaptive full tuning, which is suitable for a wireless power transmission circuit comprising an excitation source and a primary coilL ₁Primary side compensation network and secondary side coilL ₂Secondary side compensation network, load, and tuned coilL ₃And a tuning unit consisting of an additional compensation network. Tuning coilL ₃And the additional compensation network forms a loop. The advantages are that: the method has the advantages that the self-adaptive full tuning of compensation parameters can be realized under the working conditions of variable air gaps and dislocation offset without external regulation, the constant voltage or constant current output and zero input impedance angle irrelevant to load change is obtained, and the problems of large output fluctuation along with load change and large input reactive power content of the existing series/parallel, parallel/series compensation topologies and the like under the working condition of variable coupling coefficients can be solved.

In the present invention, the coil is tunedL ₃And a primary coilL ₁Secondary side coilL ₂Together forming a magnetic coupling, i.e. non-contact transformer, tuning coilL ₃Can be wound on the secondary side and shares a secondary magnetic core with the secondary coil. Or wound on the primary side and shares the primary magnetic core with the primary coil. Corresponding to the circuit part, three self-inductances are generatedL ₁、L ₂AndL ₃and three mutual inductances formed between twoM ₁₂、M ₂₃、M ₁₃。

For tuning the coilL ₃In the case of winding on the secondary side, as shown in fig. 2-7, when the relative position of the primary and secondary sides is changed, the relative position of the tuning coil and the secondary coil is fixed, and the mutual inductance is obtainedM ₂₃Can be considered approximately constant, and the tuning coil and the secondary coil can be shifted together relative to the primary coil, thereby bringing about mutual inductanceM ₁₃、M ₁₂The synchronization of (2) changes.

For the tuning coilL ₂In the case of winding on the primary side, as shown in fig. 8-18, when the relative position of the primary and secondary sides is changed, the relative position of the tuning coil and the primary coil is fixed, and the mutual inductance is generatedM ₁₃Can be approximately considered constant, and the tuning coil and the primary coil can generate position deviation relative to the secondary coil together, thereby bringing about mutual inductanceM ₂₃、M ₁₂The synchronization of (2) changes.

The first embodiment is as follows:

FIG. 2 is a diagram of a self-adaptive full-tuning wireless power transmission circuit of the present invention, which includes a voltage source and a primary side series compensation capacitorC _1sPrimary side coilL ₁Secondary side coilL ₂Secondary side parallel capacitorC _2pLoad, and method of operating the sameR _EAnd by tuning the coilL ₃And an additional compensation capacitorC ₃And forming a tuning unit. In the present embodiment, the excitation source is an ac voltage source or an equivalent ac voltage source composed of a dc source, an inverter, and a compensation network. Additional compensation capacitor used by additional compensation networkC ₃The capacitance is a single capacitance, or a plurality of capacitances are connected in series and in parallel, or an equivalent capacitance formed by combining a plurality of inductance capacitances.

The working principle of the invention for realizing the self-adaptive full tuning of the wireless power transmission system is described below with reference to fig. 2. In contrast to the prior art serial/parallel compensation topology shown in fig. 1, additionally introduced in fig. 2 isL ₃、C ₃A series loop having a loop impedance of the tuning unit of

WhereinZ _xcIs the reactance of the compensating element in the tuning unit.

In this embodiment, the tuning unit is provided on the secondary side, and the coil is tunedL ₃And a receiving coilL ₂The secondary side magnetic core is shared, so when the position of the primary side and the secondary side of the non-contact transformer changes, such as air gap change, dislocation and deviation, and the like, the two coils arranged on the secondary sideL ₃、L ₂Can simultaneously oppose the primary coilL ₁Offset and mutual inductanceM ₁₂、M ₁₃A change in (c); and two coils wound on the same sideL ₃、L ₂Because the relative position is fixed and is not influenced by the position change of the original secondary side, the change of the coupling coefficient or mutual inductance between the two sides is negligible and the two sides are approximately considered to be constant. For a certain magnetic coupling device, the self-inductance of three coils at different primary and secondary side positions can be obtained by adopting an LCR (inductance capacitance) measurement or electromagnetic field simulation modeL ₁、L ₂AndL ₃and mutual inductance between coilsM ₁₂、M ₂₃、M ₁₃And calculating the coupling coefficient between the coils based on the obtained mutual inductance value and the self-inductance valuek ₁₂、k ₂₃、k ₁₃：

Whereink ₂₃It can be considered approximately as invariant,k ₁₃andk ₁₂is a multi-element function of space position coordinate, and under the working conditions of variable air gap and dislocationk ₁₃Andk ₁₂can be changed simultaneously, and can be adjusted by reasonably optimizing the structure of the tuning coilk ₁₃Andk ₁₂when the temperature of the molten steel is changed within a certain range,k ₁₃andk ₁₂is almost constantValue, using linear function pairk ₁₃Andk ₁₂fitting to obtain a fitting function

Then it can be considered ask ₁₃Andk ₁₂is approximately equal tob，bAs a scaling factor.

The following system of equations can be written for the circuit shown in fig. 2 based on kirchhoff's voltage law:

wherein the content of the first and second substances,

are respectively asv ₁、i ₁、i _2L、i ₃Corresponding fundamental phasors.

The secondary winding can be obtained by solving the formula (6)L ₂Current of

Further, the expression of the output voltage can be found as:

wherein

. Obviously, when Δ =0, the output voltage of the system is constant, and the load resistanceR _EIs irrelevant.

Different from the traditional serial/parallel compensation topology, the primary side serial compensation capacitor is designed to meet the requirement

Then, then

It can be seen that the series compensation capacitorC _1sThe value is independent of the coupling coefficient.

Let Δ =0, the condition that the loop impedance of the constant-voltage output tuning unit needs to satisfy is solved as

Accordingly, additional compensation network reactanceZ _xcThe requirements are as follows:

the output voltage of the system is

Obviously, when the reactance of the additional compensation network in the tuning unit satisfies the formula (11), the system can output a constant output voltage regardless of the load resistance. Substituting formula (11) for formula (6) to obtain the input impedance of the resonant converter

Designing secondary side parallel compensation capacitorC _2pIs taken to satisfy

By substituting equation (14) for equation (13), the input impedance expression can be simplified to

Obviously, the input impedance is now purely resistive. Therefore, according to the embodiment of the invention, the constant voltage output and the pure resistive input impedance which are independent of the load can be obtained at the same time. In addition, as can be seen from the equations (9), (11) and (14), in the first embodiment of the present invention, each compensation capacitance parameter is only related to the designed resonant frequency, the winding self-inductance and the proportionality coefficientbAnd coupling coefficient between coils on the same sidek ₂₃In this embodiment, the tuning coil is wound on the secondary side, and under the working conditions of variable air gap and misalignment, the relative position between the two coils on the secondary side is fixed, and the coupling coefficient is fixedk ₂₃The variation of (a) is approximately negligible; the two secondary windings will simultaneously shift relative to the primary winding, resulting in a coupling coefficientk ₁₃Andk ₁₂simultaneously, the structure of the tuning coil is reasonably optimized, so that the coil can be usedk ₁₃Andk ₁₂when the temperature of the molten steel is changed within a certain range,k ₁₃andk ₁₂the ratio of the compensation capacitor to the primary side is almost a fixed value, so that the value of the compensation capacitor parameter is not influenced by the position change of the primary side and the secondary side, namely, the circuit can still realize full tuning under the working conditions of variable air gaps and offset.

The design method of the compensation parameters of the wireless power transmission circuit capable of self-adapting and fully tuning based on the series/parallel compensation topology comprises the following steps:

a: transforming the relative position between the original and the secondary sides to obtain the coupling coefficient under various conditionsk ₂₃Coupling coefficient ofk ₁₂Coupling coefficient ofk ₁₃A value of (d);

b: fitting the obtained coupling coefficient by using a linear function to obtain a fitting function

WhereinbIs a proportionality coefficient;

c: designing a primary side series compensation capacitor

；

D: designing secondary side parallel compensation capacitor

；

E: designing reactance of additional compensation networkZ _xcSatisfy the requirement of

。

Preferably, the coil is tunedL ₃And secondary windingL ₂Are decoupled from one another, i.e. cancelledM ₂₃The influence of (c) can be by means of magnetic or electrical decoupling.

For the case of magnetic decoupling, optimization can be carried outL ₃Coil construction, or regulationL ₃AndL ₂relative position between them, or by adding metallic material and/or high permeability materialL ₃AndL ₂the coupling magnetic fluxes between the two parts mutually offset, thereby realizing mutual inductanceM ₂₃Coupling coefficient ofk ₂₃Is approximately zero, and each compensation element parameter is determined by

WhereinbIs a scaling factor. The loop impedance of the tuning unit can be adjusted by mutual inductanceM ₁₃Reflected to the primary side, as shown in FIG. 3, and has a refractive impedance of

Equivalent impedance Z_r3It is a capacitive reactance or an inductive reactance, and its equivalent and compensation capacitances can be seenC _1sConnected in series, common to the primary transmission coilL ₁Resonance, then Z is adjusted_r3I.e. the equivalent parameters of the primary resonant network can be adjusted accordingly. Therefore, the present invention adds a tuning coilThe loop essentially plays a role in adjusting the impedance of the primary resonant network, but is different from the traditional tuning circuit in that the invention utilizes mutual inductance under the working conditions of variable air gaps and dislocationM ₁₃And a main power transmission coilL ₁、L ₂Mutual inductance betweenM ₁₂The aim of self-tuning is realized by a naturally existing mapping relation, namely, additional control units such as sampling units, switches and the like are not required to be introduced, and compensation parameters are reasonably designed to enable a tuning coil to be tunedL ₃By mutual inductanceM ₁₃Equivalent impedance self-adaptive compensation reflected to primary side transmitting coil loop due to mutual inductanceM ₁₂The impact of the change on the operating characteristics of the system.

Based on mutual inductance model of transformer, it can obtain secondary side coil loop to primary side coilL ₁Has a reflection impedance of

The input impedance and output voltage of the converter are expressed as

It can be seen that the imaginary part of the input impedance is simultaneously coupled by the coefficientk ₁₃Andk ₁₂influence. For the conventional serial/parallel compensation topology, there arek ₁₃If not =0, thenk ₁₂When the input impedance changes, the imaginary part of the input impedance also changes, so that the angle of the input impedance is increased or reduced, the converter works under the strong inductive or strong capacitive working condition, and simultaneously, the output voltage of the converter and the load resistance also changeR _EAnd (4) correlating. In the embodiment of the invention, the tuning unit introduces a dependent coupling coefficient in the circuitk ₁₂Variables that change synchronouslyk ₁₃When is coming into contact withk ₁₃Andk ₁₂the variation trends are the same, and when the proportional relation is approximately satisfied, the main power coil can be compensated in a self-adaptive manner without external regulationL ₁、L ₂Coefficient of intercouplingk ₁₂The effect of the variation on the input impedance angle and the output voltage. Based on fundamental wave equivalence, when the design of the compensation parameters is satisfied, the output voltage and the input impedance of the self-adaptive full-tuning wireless power transmission circuit are respectively as follows:

it can be seen that the provided wireless power transmission circuit capable of self-adapting and full tuning can obtain constant voltage output and pure-resistance input impedance which are irrelevant to load as the traditional series/parallel compensation circuit is the same, and meanwhile, because the parameters of the primary side series compensation capacitor and the secondary side parallel compensation capacitor are only relevant to the designed resonance frequency and transformer self-inductance and irrelevant to the mutual inductance change of the magnetic coupler as shown in formula (16), under the working condition of variable coupling coefficient, the wireless power transmission circuit capable of self-adapting and full tuning still has the pure-resistance characteristics of output constant voltage and input impedance, such as air gap change, dislocation offset and the like of the primary side magnetic coupler and the secondary side magnetic coupler, which is a significant advantage of the invention different from the traditional series/parallel compensation circuit.

For the circuit decoupling condition, the decoupling inductance or the decoupling capacitance can be serially connected to counteractM ₂₃Referring to fig. 4 and 6, the circuit connection manner of the second embodiment and the third embodiment of the present invention is formed.

Example two:

FIG. 4 is a diagram of a self-adaptive full-tuning wireless power transmission circuit of the present invention, which includes a voltage source and a primary side series compensation capacitorC _1sPrimary side coilL ₁Secondary side coilL ₂Secondary side parallel capacitorC _2pLoad, and method of operating the sameR _EAnd by tuning the coilL ₃And an additional compensation capacitorC ₃And forming a tuning unit.

The difference between this embodiment and the first embodiment is that decoupling inductance is introduced to cancel outM ₂₃The influence of (c). In FIG. 4, the primary winding with additional coupling inductorL _2mSecondary windingL _3mAre respectively connected in series with the receiving coilL ₂Tuning coilL ₃In the loop, two dotted terminals of the coupling inductor are respectively connected with the coilL ₃And a coilL ₂Are connected, the mutual inductance of the coupling inductor isM _mMust satisfyM _m= M ₂₃The equivalent circuit is shown in fig. 5. It should be noted that, after the introduction of the decoupling inductance,L ₂、L ₃the inductance of the series circuit will change, and as shown in fig. 5, the value of the corresponding compensation parameter will change correspondingly, where the primary side series compensation capacitor is designed to resonate with the self-inductance of the transmitter coil, the secondary side parallel compensation capacitor is designed to resonate with the equivalent inductance of the series circuit of the receiver coil, and the additional compensation capacitorC ₃To achieve a zero imaginary input impedance design, the compensation element design formula in step C, D, E of the compensation parameter design method is replaced with equation (21).

WhereinbIs a proportionality coefficient;

c: designing a primary side series compensation capacitor

；

D: designing secondary side parallel compensation capacitor

；

。

Example three:

FIG. 6 is a diagram of a self-adaptive full-tuning wireless power transmission circuit of the present invention, which includes a voltage source and a primary side series compensation capacitorC _1sPrimary side coilL ₁Secondary side coilL ₂Secondary side parallel capacitorC _2pLoad, and method of operating the sameR _EAnd by tuning the coilL ₃And an additional compensation capacitorC ₃And forming a tuning unit.

The difference between this embodiment and the first embodiment is that decoupling capacitance is added in series to cancelM ₂₃The influence of (c). In FIG. 6, the receiving coilL ₂And tuning coilL ₃Is connected with the same name terminal of the capacitor, and the decoupling capacitorC _mOne end of (A) andL ₂、L ₃is connected with the common terminal, and the other end is connected with the parallel compensation capacitorC _2pAnd an additional compensation capacitorC ₃Is connected with the common terminal and the decoupling capacitorC _mThe parameters must satisfy

The equivalent circuit is shown in fig. 7. It should be noted that, after introducing the decoupling capacitance,L ₂、L ₃the inductance of the series loop will change, and as shown in fig. 7, the value of the corresponding compensation parameter will change correspondingly, where the primary side series compensation capacitor is designed to resonate with the self-inductance of the transmitting coil, and the secondary side parallel compensationThe capacitor design and the equivalent inductance resonance of the receiving coil series loop are added with a compensation capacitorC ₃To achieve a zero imaginary input impedance design, the compensation element design formula in step C, D, E of the compensation parameter design method is replaced by the following formula.

WhereinbIs a proportionality coefficient;

c: designing a primary side series compensation capacitor

；

D: designing secondary side parallel compensation capacitor

；

。

Example four:

FIG. 8 is a diagram of a self-adaptive full-tuning wireless power transmission circuit according to the present invention, which omits a secondary parallel compensation capacitor compared to the wireless power transmission circuit shown in FIG. 3C _2pIn the case of the single primary side capacitance compensation structure, the compensation parameter design method in this embodiment is the same as that in the first embodiment, becauseC _2pThe converter is connected in parallel with the output end and has no influence on the output voltage characteristic, so that the converter still has self-adaptive full tuning under the working condition of variable coupling coefficient, and provides constant voltage output irrelevant to load change, but the corresponding input impedance is not pure resistance at the moment, and the output voltage is not influencedM ₂₃Under the condition of =0, the input impedance of the embodiment is

It can be seen that the input impedance of the transformer is inductive at this time, and the inductive angle is related to the operating frequency, the self-inductance of the receiving coil, and the load resistance.

Embodiments five to fourteen are cases where the tuning unit is disposed on the primary side, and the working principle of implementing the adaptive full tuning of the wireless power transmission system is similar to the embodiments, and the differences are that when the relative position of the primary side and the secondary side of the charging is changed, the relative position of the tuning coil and the primary side coil is fixed, and the coupling coefficient is fixedk ₁₃Can be approximately considered constant, and the tuning coil and the primary coil can generate position deviation relative to the secondary coil together to bring mutual inductanceM ₂₃、M ₁₂The synchronous variation of (1), therefore, in the fifth to the fourteenth embodiments, mutual inductance is utilizedM ₂₃Is adapted to compensate for mutual inductanceM ₁₂The influence on the power transmission characteristic can be realized by reasonably optimizing and tuning the coil structurek ₂₃Andk ₁₂when the temperature of the molten steel is changed within a certain range,k ₂₃andk ₁₂is almost constant, and is paired by a linear functionk ₂₃Andk ₁₂fitting to obtain a fitting function, then it can be considered ask ₂₃Andk ₁₂is approximately equal toa. Preferably, in the fifth to fourteenth embodiments, the tuning coil and the primary coil are decoupled from each other, and the implementation method may be similar to the examples given in the second and third embodiments in a magnetic decoupling or circuit decoupling manner.

Example five:

FIG. 9 is a diagram of a self-adaptive full-tuning wireless power transmission circuit of the present invention, which includes a current source and a primary side parallel compensation capacitorC _p1Primary side coilL ₁Secondary side coilL ₂Secondary side series capacitorC _s2Load, and method of operating the sameR _EAnd by tuning the coilL ₃And a tuning unit consisting of an additional compensation network. The excitation source is an alternating current source or an equivalent alternating current source composed of a direct current source, an inverter and a compensation network. Additional compensation capacitorC ₃The capacitance is a single capacitance, or a plurality of capacitances are connected in series and in parallel, or an equivalent capacitance formed by combining a plurality of inductance capacitances.

In this example, the coil will be tunedL ₃Fixed to the primary side and the primary coilL ₁Sharing a primary magnetic core. Then when the position of the primary side and the secondary side of the non-contact transformer is changed, the two coils on the primary side and the secondary sideL ₃、L ₁Can simultaneously oppose the secondary side coilL ₂Offset so that the power transmission coilL ₁AndL ₂mutual inductance betweenM ₁₂When changed, the corresponding tuning coil is accompaniedL ₃And secondary windingL ₂Mutual inductance betweenM ₂₃A change in (c). For a certain magnetic coupling device, the self-inductance of three coils at different primary and secondary side positions can be obtained by adopting an LCR (inductance capacitance) measurement or electromagnetic field simulation modeL ₁、L ₂AndL ₃and mutual inductance between coilsM ₁₂、M ₂₃、M ₁₃And calculating the coupling coefficient between the coils based on the obtained mutual inductance value and the self-inductance valuek ₁₂、k ₂₃、k ₁₃Then, the position under different positions can be obtainedk ₁₂、k ₂₃With an exact mapping relationship between them, using linear function pairsk ₂₃Andk ₁₂fitting to obtain a fitting function, then it can be considered ask ₂₃Andk ₁₂is approximately equal toa。

The design method of the compensation parameters of the wireless power transmission circuit based on the parallel/serial compensation topology and capable of self-adapting and full tuning comprises the following steps:

WhereinaIs a proportionality coefficient;

c: designing a primary side series compensation capacitor

；

D: designing secondary side parallel compensation capacitor

；

。

Preferably, the coil is tunedL ₃And a primary coilL ₁Are decoupled from one another, i.e. cancelledM ₁₃The influence of (c) can be by means of magnetic or electrical decoupling. For the case of circuit decoupling, the implementation of the circuit is similar to that in fig. 4 and 6, which is not described herein again, and the parameter design method after introducing the decoupling circuit may refer to the second embodiment and the third embodiment in combination with the formula in step C, D, E. For the case of magnetic decoupling, mutual inductanceM ₁₃Coupling coefficient ofk ₁₃Approximately zero, when the compensation element parameters are determined by

WhereinaIs a scaling factor. Based on the mutual inductance model of the transformer, the loop from the tuning unit to the secondary coil can be obtainedL ₂Has a reflection impedance of

It can be seen that the equivalent impedance Z_r3As an inductive reactance, its equivalent and compensation capacitanceC _2sIn series, common to secondary receiving coilsL ₁Resonance, then Z is adjusted_r3I.e. the equivalent parameters of the secondary resonant network can be adjusted accordingly. Therefore, the additional tuning coil loop of the invention essentially plays a role in adjusting the impedance of the secondary side resonant network, but is different from the traditional tuning circuit in that the invention utilizes the mutual inductance under the working conditions of variable air gaps and dislocationM ₂₃And power transmission coilL ₁、L ₂Mutual inductance betweenM ₁₂The aim of self-tuning is realized by a naturally existing mapping relation, namely, additional control units such as sampling units, switches and the like are not required to be introduced, and compensation parameters are reasonably designed to enable a tuning coil to be tunedL ₃By mutual inductanceM ₂₃The equivalent impedance self-adaptive compensation reflected to the secondary side receiving coil loop is due to mutual inductanceM ₁₂The impact of the change on the operating characteristics of the system.

Based on the basic circuit law, the input impedance of the converter can be determined as

It can be seen that the imaginary part of the input impedance is simultaneously coupled by the coefficientk ₂₃Andk ₁₂effects, for the traditional parallel/serial compensation topology, there arek ₂₃If not =0, thenk ₁₂When the input impedance angle of the converter changes, the converter works under a strong-sensitivity working condition, and the transmission efficiency is influenced. In the embodiment of the invention, the added tuning unit is arranged in the circuitIntroducing a random coupling coefficientk ₁₂Variables that change synchronouslyk ₂₃When is coming into contact withk ₂₃Andk ₁₂the variation trends are the same, and when the proportional relation is approximately satisfied, the main power coil can be compensated in a self-adaptive manner without external regulationL ₁、L ₂Coefficient of intercouplingk ₁₂The effect of the variation on the input impedance angle. Based on fundamental wave equivalence, under the condition of complete compensation, the output current and the input impedance of the self-adaptive full-tuning wireless power transmission circuit are respectively as follows:

it can be seen that the self-adaptive full-tuned wireless power transmission circuit can obtain constant current output irrelevant to a load and pure-resistance input impedance, meanwhile, because parameters of a primary side parallel compensation capacitor and a secondary side series compensation capacitor of the self-adaptive full-tuned wireless power transmission circuit are only relevant to designed resonant frequency and transformer self-inductance, are irrelevant to magnetic coupler mutual inductance change and are not easy to detune, as shown in formula (24), under the working condition of variable coupling coefficients, such as air gap change, dislocation offset and the like of an original secondary side magnetic coupler, the self-adaptive full-tuned wireless power transmission circuit still has the pure-resistance characteristics of output constant current and input impedance.

Example six:

FIG. 10 is a diagram of a wireless power transmission circuit with adaptive full tuning, the topology of the primary circuit is the same as that of FIG. 9, and the secondary compensation network adoptsLCLThe compensation structure comprises a compensation inductorL _{f_2}And compensation capacitorC _{f_2}Secondary side coilL ₂Compensating inductanceL _{f_2}A compensation capacitor connected with the load in sequenceC _{f_2}Connected in parallel to the secondary coilL ₂At both ends of the same.

The method for designing the compensation parameters of the wireless power transmission circuit based on the primary side series compensation and the secondary side LCL compensation and capable of being self-adaptive and fully tuned comprises the following steps:

WhereinaIs a proportionality coefficient;

c: designing a primary side series compensation capacitor

；

D: designing parameters of a secondary side compensation element:

；

。

Preferably, the coil is tunedL ₃And a primary coilL ₁Are decoupled from one another, i.e. cancelledM ₁₃The influence of (c) can be by means of magnetic or electrical decoupling. For the case of circuit decoupling, the implementation of the circuit is similar to that in fig. 4 and 6, which is not described herein again, and the parameter design method after introducing the decoupling circuit may refer to the second embodiment and the third embodiment in combination with the formula in step C, D, E. For the case of magnetic decoupling, mutual inductanceM ₁₃Coupling coefficient ofk ₁₃Approximately zero, based on the fundamental wave equivalent, it can be inferred that under the condition of complete compensation, the output voltage and the input impedance of the present embodiment are respectively:

it can be seen that the self-adaptive full-tuned wireless power transmission circuit can obtain constant voltage output and pure-resistance input impedance which are irrelevant to load, and meanwhile, because the parameters of the compensation element of the self-adaptive full-tuned wireless power transmission circuit are only relevant to the designed resonant frequency and transformer self-inductance and irrelevant to the mutual inductance change of a magnetic coupler, the self-adaptive full-tuned wireless power transmission circuit is not easy to detune under the working condition of variable coupling coefficients, such as air gap change, dislocation offset and the like of an original secondary magnetic coupler, and the self-adaptive full-tuned wireless power transmission circuit still has the pure-resistance characteristics of output constant voltage and input impedance.

Example seven:

FIG. 11 is a diagram of a self-adaptive full-tuning wireless power transmission circuit, the topology of the primary circuit of which is the same as that of FIG. 9, and the secondary compensation network of which adoptsLCCThe compensation structure comprises a compensation inductorL _{f_2}A first compensation capacitorC _{f_21}And a second compensation capacitorC _{f_22}Secondary side coilL ₂A second compensation capacitorC _{f_22}Compensating inductanceL _{f_2}A first compensation capacitor connected with the load in sequenceC _{f_21}Connected in parallel to the secondary coilL ₂And a second compensation capacitorC _{f_22}Two ends of the series branch.

The method for designing the compensation parameters of the wireless power transmission circuit based on the primary side series compensation and the secondary side LCC compensation and capable of being self-adaptive and fully tuned comprises the following steps:

WhereinaIs a proportionality coefficient;

c: designing a primary side series compensation capacitor

；

D: design of secondary compensation element parameters

；

。

Preferably, the coil is tunedL ₃And a primary coilL ₁Are decoupled from one another, i.e. cancelledM ₁₃The influence of (c) can be by means of magnetic or electrical decoupling. The input and output characteristics of this embodiment are similar to those of the sixth embodiment of the present invention, except that the seventh embodiment introduces a new adjustable free variableC _{f_21}And the design freedom degree is higher.

Example eight:

FIG. 12 is a diagram of an adaptive full-tuning wireless power transmission circuit according to the present invention, including a voltage source and a primary coilL ₁Secondary side coilL ₂Secondary side series capacitorC _2sLoad, and method of operating the sameR _EAnd series-connected tuning coilsL ₃And additional compensation capacitorC ₃. In the present embodiment, the excitation source is an ac voltage source or an equivalent ac voltage source composed of a dc source, an inverter, and a compensation network. Additional compensation capacitorC ₃The capacitance is a single capacitance, or a plurality of capacitances are connected in series and in parallel, or an equivalent capacitance formed by combining a plurality of inductance capacitances.

The design method of the compensation parameters of the wireless power transmission circuit based on the single-auxiliary-side series compensation and capable of self-adapting full tuning comprises the following steps:

b: fitting the obtained coupling coefficient by using a linear function to obtainTo fitting function

WhereinaIs a proportionality coefficient;

c: design of secondary compensation element parameters

；

D: designing reactance of additional compensation networkZ _xcSatisfy the requirement of

。

WhereinaIs a scaling factor. The tuning unit has a loop impedance of

。

Based on the mutual inductance model of the transformer, the output voltage of the resonance converter can be obtained as

It can be seen that the load resistanceR _ECoefficient of (2) simultaneous coupled coefficientk ₂₃Andk ₁₂effects on the conventional single primary side compensation topology arek ₂₃If not =0, thenk ₁₂The converter loses constant voltage characteristics in response to changes in load resistance. In the embodiment of the invention, the added tuning unit introduces a dependent coupling coefficient in the circuitk ₁₂Variables that change synchronouslyk ₂₃When is coming into contact withk ₂₃Andk ₁₂the variation trends are the same, and when the proportional relation is approximately satisfied, the main power coil can be compensated in a self-adaptive manner without external regulationL ₁、L ₂Coefficient of intercouplingk ₁₂The effect of the variation on the output voltage. Based on fundamental wave equivalence, when the compensation parameters are satisfied, the output voltage of the self-adaptive full-tuning wireless power transmission circuit is as follows:

obviously, the resonant converter of the present embodiment can always output a constant voltage independent of load variation, and in addition, as shown in formula (30), the compensation element parameters are only related to the designed resonant frequency, transformer self-inductance and proportionality coefficient, so that under the working condition of variable coupling coefficient, such as air gap variation, dislocation offset and the like of the primary and secondary magnetic couplers, the circuit is not easy to detune, and can always work in a full tuning state.

Example nine:

FIG. 13 is a diagram of an adaptive full-tuning wireless power transmission circuit according to the present invention, including a voltage source and a primary coilL ₁Primary side compensation network and secondary side coilL ₂Secondary side series capacitorC _2sLoad, and method of operating the sameR _EAnd by tuning the coilL ₃And a tuning unit consisting of an additional compensation network. Wherein the excitation source is an AC voltage source or an equivalent AC voltage source composed of a DC source, an inverter and a compensation network, and a compensation capacitor is addedC ₃For a single capacitor or for multiple capacitors in series-parallelThe primary side compensation network adopts an LCL structure and comprises a compensation inductorL _{f_1}And compensation capacitorC _{f_11}Excitation source, compensation inductanceL _{f_1}And a primary coilL ₁Sequentially connected, compensating capacitorsC _{f_1}Connected in parallel to the primary coilL ₁Two ends.

The method for designing the compensation parameters of the wireless power transmission circuit based on the primary LCL compensation and secondary series compensation and capable of being self-adaptive and fully tuned comprises the following steps:

WhereinaIs a proportionality coefficient;

c: designing a primary side compensation inductanceL _{f_1}And compensation capacitorC _{f_11}The parameters satisfy:

；

d: designing secondary side series compensation capacitance parameters:

；

。

Preferably, the coil is tunedL ₃And a primary coilL ₁Are decoupled from one another, i.e. cancelledM ₁₃The influence of (c) can be by means of magnetic or electrical decoupling.For the case of circuit decoupling, the implementation of the circuit is similar to that in fig. 4 and 6, which is not described herein again, and the parameter design method after introducing the decoupling circuit may refer to the second embodiment and the third embodiment in combination with the formula in step C, D, E. For the case of magnetic decoupling, mutual inductanceM ₁₃Coupling coefficient ofk ₁₃Approximately zero when the input impedance of the resonant converter is

It can be seen that the imaginary part of the input impedance is simultaneously coupled by the coefficientk ₂₃Andk ₁₂effects for the conventional LCL/S compensation topology, there arek ₂₃If not =0, thenk ₁₂When the input impedance angle of the converter changes, the converter works under a strong-sensitivity working condition, and the transmission efficiency is influenced. In the embodiment of the invention, the added tuning unit introduces a dependent coupling coefficient in the circuitk ₁₂Variables that change synchronouslyk ₂₃When is coming into contact withk ₂₃Andk ₁₂the variation trends are the same, and when the proportional relation is approximately satisfied, the adaptive compensation can be realized without external regulationk ₁₂The effect of the variation on the input impedance. Based on fundamental wave equivalence, when the compensation parameters are satisfied, the input impedance of the self-adaptive full-tuning wireless power transmission circuit is as follows:

obviously, the input impedance is now purely resistive, so tuned coils are usedL ₃And a receiving coilL ₂Coefficient of coupling betweenk ₂₃Andk ₁₂the characteristic of simultaneous increase and reduction can self-adaptively compensate the influence of the change of the coupling coefficient between the primary and secondary power windings on the input impedance characteristic of the system, so that the resonant converter always works in a full-tuning state, the input impedance is pure resistance, and the realization is realized in a wide load and coupling coefficient change rangeZero reactive power is input, reactive circulation of the system is reduced, and stress of devices is reduced.

Further, the output current gain of the converter when the designed compensation parameter is satisfied can be obtained as

The adaptive full-tuning wireless power transmission circuit can obtain constant current output irrelevant to load, and is not easy to detune under the variable coupling working condition because the parameters of the primary and secondary compensation elements are only relevant to the designed resonant frequency, the transformer self-inductance and the proportionality coefficient.

Example ten:

FIG. 14 is a diagram of an adaptive full-tuning wireless power transmission circuit according to the present invention, including a voltage source and a primary coilL ₁Primary side LCL compensation network and secondary side coilL ₂Secondary LCL compensation network, loadR _EAnd by tuning the coilL ₃And a tuning unit consisting of an additional compensation network. Wherein the excitation source is an AC voltage source or an equivalent AC voltage source composed of a DC source, an inverter and a compensation network, and a compensation capacitor is addedC ₃The primary side compensation network and the secondary side compensation network both adopt LCL structures for a single capacitor or equivalent capacitors formed by connecting a plurality of capacitors in series-parallel or combining a plurality of inductance capacitors, wherein the primary side compensation network comprises compensation inductorsL _{f_1}And compensation capacitorC _{f_11}Excitation source, compensation inductanceL _{f_1}And a primary coilL ₁Sequentially connected, compensating capacitorsC _{f_1}Connected in parallel to the primary coilL ₁Two ends; the secondary compensation network comprises a compensation inductorL _{f_2}And compensation capacitorC _{f_2}Secondary side coilL ₂Compensating inductanceL _{f_2}A compensation capacitor connected with the load in sequenceC _{f_2}Connected in parallel to the secondary coilL ₂At both ends of the same.

The design method of the compensation parameters of the self-adaptive full-tuning wireless power transmission circuit based on bilateral LCL compensation comprises the following steps:

WhereinaIs a proportionality coefficient;

c: designing a primary side compensation inductanceL _{f_1}And compensation capacitorC _{f_1}The parameters satisfy:

；

d: designing secondary compensation inductanceL _{f_2}Compensating capacitorC _{f_2}The parameters satisfy:

；

。

Preferably, the coil is tunedL ₃And a primary coilL ₁Are decoupled from one another, i.e. cancelledM ₁₃The influence of (c) can be by means of magnetic or electrical decoupling. For the case of magnetic decoupling, mutual inductanceM ₁₃Coupling coefficient ofk ₁₃Approximately zero, when the above-mentioned compensation parameter design is satisfied, the proposed adaptive full tuningThe input impedance and the output voltage gain of the wireless power transmission circuit are

Obviously, the present embodiment has the characteristics of pure resistance of input impedance and independence of output voltage and load resistance. Using tuned coilsL ₃And a receiving coilL ₂Coefficient of coupling betweenk ₂₃Andk ₁₂the characteristic of increasing and decreasing can realize the self-tuning of the input impedance under the variable coupling working condition, so that the resonant converter always works near the zero input impedance angle.

Example eleven:

FIG. 15 is a diagram of an adaptive full-tuning wireless power transmission circuit according to the present invention, including a voltage source and a primary coilL ₁Primary side LCL compensation network and secondary side coilL ₂Secondary LCC compensation network, loadR _EAnd by tuning the coilL ₃And a tuning unit consisting of an additional compensation network. Wherein the excitation source is an AC voltage source or an equivalent AC voltage source composed of a DC source, an inverter and a compensation network, and a compensation capacitor is addedC ₃The primary side compensation network adopts an LCL structure and comprises a compensation inductorL _{f_1}And compensation capacitorC _{f_11}Excitation source, compensation inductanceL _{f_1}And a primary coilL ₁Sequentially connected, compensating capacitorsC _{f_1}Connected in parallel to the primary coilL ₁Two ends; the secondary compensation network adopts LCC structure and compensation inductanceL _{f_2}A first compensation capacitorC _{f_21}And a second compensation capacitorC _{f_22}Secondary side coilL ₂A second compensation capacitorC _{f_22}Compensating inductanceL _{f_2}A first compensation capacitor connected with the load in sequenceC _{f_21}Connected in parallel to the secondary coilL ₂And a second compensation capacitorC _{f_22}Two ends of the series branch.

The method for designing the compensation parameters of the wireless power transmission circuit capable of self-adapting and fully tuning based on the primary LCL compensation and the secondary LCC compensation comprises the following steps:

WhereinaIs a proportionality coefficient;

；

d: designing secondary compensation inductanceL _{f_2}Compensating capacitorC _{f_21}、C _{f_22}The parameters satisfy:

；

。

Preferably, the coil is tunedL ₃And a primary coilL ₁Are decoupled from one another, i.e. cancelledM ₁₃The influence of (c) can be by means of magnetic or electrical decoupling. For the case of magnetic decoupling, mutual inductanceM ₁₃Coupling coefficient ofk ₁₃Approximately zero, when the above-mentioned compensation parameter design is satisfied, the proposed adaptive methodThe input impedance and the output voltage gain of the fully tuned wireless power transmission circuit are

Example twelve:

FIG. 16 is a diagram of an adaptive full-tuning wireless power transmission circuit according to the present invention, including a voltage source and a primary coilL ₁Primary side LCC compensation network and secondary side coilL ₂Secondary side series compensation capacitorC _s2Load, and method of operating the sameR _EAnd by tuning the coilL ₃And a tuning unit consisting of an additional compensation network. Wherein the excitation source is an AC voltage source or an equivalent AC voltage source composed of a DC source, an inverter and a compensation network, and a compensation capacitor is addedC ₃The primary side compensation network adopts an LCC structure and comprises a primary side compensation inductorL _{f_1}First compensation capacitor on primary sideC _{f_11}Primary side second compensation capacitorC _{f_12}Primary side compensation inductanceL _{f_1}Primary side second compensation capacitorC _{f_12}And a primary coilL ₁Sequentially connected first compensation capacitors on the primary sideC _{f_11}Connected in parallel to the primary coilL ₁And_fprimary side second compensation capacitorC _{f_12}Two ends of the series branch.

The method for designing the compensation parameters of the wireless power transmission circuit based on the primary LCC compensation secondary series compensation and capable of being self-adaptive and fully tuned comprises the following steps:

WhereinaIs a proportionality coefficient;

c: designing a primary side compensation inductanceL _{f_1}First compensation capacitor on primary sideC _{f_11}Second compensation capacitor with primary sideC _{f_12}Parameters are as follows:

；

d: designing secondary side series compensation capacitorC _s2Comprises the following steps:

；

。

Preferably, the coil is tunedL ₃And a primary coilL ₁Are decoupled from one another, i.e. cancelledM ₁₃The influence of (c) can be by means of magnetic or electrical decoupling. The input and output characteristics of the topology of the present embodiment are similar to those of the ninth embodiment, and when the compensation parameter design is satisfied, the constant current output irrelevant to the load can be realized, and meanwhile, the tuning coil is utilizedL ₃And a receiving coilL ₂Coefficient of coupling betweenk ₂₃Andk ₁₂the characteristics of simultaneous increase and simultaneous decrease can be realized in a wide load and wide coupling coefficient variation rangeThe self-tuning of the input impedance is realized, so that the resonant converter always works near a zero input impedance angle. The difference between the twelfth embodiment and the ninth embodiment is that the primary side of the twelfth embodiment introduces a new adjustable free variableC__f12And a parameter design freedom degree is provided, and the transmission requirements of different powers and output currents can be met.

The secondary side compensation network in this embodiment may also adopt LCL and LCC compensation structures, as shown in fig. 17 and 18, fig. 17 and 18 respectively correspond to the wireless power transmission circuit topology capable of adaptive full tuning in the thirteenth and fourteenth embodiments of the present invention, the parameter design of the primary side compensation element is the same as the twelfth embodiment, and the parameter design of the secondary side compensation element is the same as the tenth and eleventh embodiments, respectively, so as to obtain a constant voltage output unrelated to the load, which is not described herein again.

The above description is only a preferred example of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Simulation example:

in order to verify the superiority and feasibility of the invention, saber simulation software is used to simulate the first embodiment of the wireless power transmission circuit capable of self-adapting and full tuning shown in the attached figure 2.v ₁、i ₁Respectively, an alternating input voltage and a current,v ₂、i ₂respectively the ac output voltage and current of the converter,R _Eis an ac equivalent load.

The specific simulation parameters are as follows:

input voltage	V ₁ = 1.V
		Compensating the frequency completely	40kHz
Compensating for magnetic coupling parameters at a location	L ₁=635.91mH, L ₂=673.51mH，L ₃ =650mH, M ₁₂=310.86mH, k ₁₂=0.475，M ₁₃=299mH, k ₁₃=0.465，M ₂₃=0mH, k ₂₃= 0
		Resonance capacitor	C ₁=24.896n_F, C ₂=23.506n_F，C ₃=12.43n_F

FIG. 19 shows the measurement results of the coupling coefficient of the magnetic coupling device under the variable air gap condition, and Matlab or Excel software is adopted to use linear function pairsk ₁₃Andk ₁₂fitting, fitting curve as shown in FIG. 20, obtaining fitting function ofk ₁₃ = 0.96 k ₁₂Coefficient of proportionalitybIs 0.96. FIG. 21 shows the compensation position of the first embodiment (k ₁₂= 0.475，k ₁₃= 0.465) simulation curves of open loop gain and input impedance phase angle under different load conditions, and fig. 22 is (under variable air gap working condition) (k ₁₂=k ₁₃=0.2), and the simulation result shows that the wireless power transmission circuit capable of self-adapting and full tuning provided by the invention has variable load gain intersection points under different coupling coefficients, and the input impedance at the frequency of the gain intersection pointsThe angles are all zero, and the frequency of the gain intersection point obtained by simulation is 40kHz, consistent with the fully compensated frequency of theoretical design.

To prove the superiority of the present invention, simulation studies were carried out using the existing primary side series-secondary side parallel (series/parallel) compensation topology shown in fig. 1, and fig. 23 and 24 show the existing series/parallel compensation topology at the compensation position: (fig.: 23 and 24 respectivelyk ₁₂=k ₁₃=0.475), position of displacement: (k ₁₂=k ₁₃=0.275), whereC ₁With the value of 32.15nF, it can be seen that at the complete compensation position, the existing serial/parallel compensation circuit has the characteristic that the input phase angle at the gain intersection point is zero, but after the coupling coefficient is changed, although the gain intersection point still exists, the working frequency corresponding to the gain intersection point deviates from the initially set working frequency point, and meanwhile, the input impedance is no longer purely resistive, 40 nFkAt the Hz operating frequency, the input impedance has a large inductive angle, which increases the reactive circulating current and affects the transmission efficiency.

FIG. 25 shows simulated input impedance angles at different coupling coefficients for the application of the embodiment with an operating frequency of 40kHz, the load resistance is 50 omega, and for comparison, the simulation result of the input impedance angle of the traditional serial/parallel compensation circuit under the variable coupling coefficient is also shown in the figure. As can be seen from FIG. 25, the input phase angle of the proposed adaptive fully tunable wireless power transmission topology is in the coupling coefficientk ₁₂The input impedance is always zero in the variation process, namely the input impedance keeps pure resistance unchanged; the input phase angle of the converter with the compensation of the series connection of the primary side and the parallel connection of the secondary side is in the coupling coefficientk ₁₂The input impedance is gradually changed from pure resistance to inductance in the process of gradually increasing from big to small.

Claims

1. A method for designing compensation parameters of a wireless power transmission device capable of self-adapting and full tuning is suitable for a wireless power transmission circuit comprising an excitation source, a primary side compensation network and a primary side coilL ₁Secondary side coilL ₂Secondary side compensation network, load, and tuned coilL ₃Tuning with additional compensation networkA unit; the tuning unit is arranged at the side of the secondary side, and the coil is tunedL ₃And secondary windingL ₂A common secondary side magnetic core; or the tuning unit is arranged at the primary side, and the coil is tunedL ₃And a primary coilL ₁A common primary side magnetic core; tuning coilL ₃And secondary windingL ₂Has a coupling coefficient ofk ₂₃Primary side coilL ₁And secondary windingL ₂Has a coupling coefficient ofk ₁₂Primary side coilL ₁And tuning coilL ₃Has a coupling coefficient ofk ₁₃；

The parameter design steps of the tuning unit are as follows:

WhereinbIs a proportionality coefficient;

WhereinaIs a proportionality coefficient;

for the case where the tuning unit is arranged on the secondary side,

for the case where the tuning unit is placed on the primary side,

2. The method for designing compensation parameters of an adaptive fully tunable wireless power transmission device according to claim 1, wherein the tuning unit is placed on a secondary side, and the tuning coil and the secondary side coil are decoupled from each other; alternatively, the tuning unit is placed on the primary side, and the tuning coil and the primary coil are decoupled from each other.

3. The method for designing compensation parameters of an adaptive full-tunable wireless power transmission device according to claim 1 or 2, further comprising the following steps:

c) the tuning unit is placed on the secondary side.

4. The method for designing compensation parameters of an adaptive full-tunable wireless power transmission device according to claim 1 or 2, further comprising the following steps:

for theThe secondary compensation network adopts LCL compensation structure condition, and the compensation network comprises compensation inductanceL _{f_2}And compensation capacitorC _{f_2}Secondary side coilL ₂Compensating inductanceL _{f_2}A compensation capacitor connected with the load in sequenceC _{f_2}Connected in parallel to the secondary coilL ₂The compensation parameter design satisfies the following requirements:

5. The method for designing compensation parameters of an adaptive full-tunable wireless power transmission device according to claim 1 or 2, further comprising the following steps:

b) the secondary side compensation network adopts a series capacitance compensation structure and compensation capacitanceC _2sAnd pairSide coilL ₂The parameters are calculated by the following formula:

6. The method for designing compensation parameters of an adaptive full-tunable wireless power transmission device according to claim 1 or 2, further comprising the following steps:

7. The method for designing compensation parameters of an adaptive full-tunable wireless power transmission device according to claim 1 or 2, further comprising the following steps:

8. The method for designing compensation parameters of an adaptive full-tuning wireless power transmission device according to claim 1, wherein the excitation source is an ac voltage source or an equivalent ac voltage source consisting of a dc source, an inverter and a compensation network.

9. The method for designing compensation parameters of an adaptive full-tuning wireless power transmission device according to claim 4, wherein the excitation source is an AC current source or an equivalent AC current source composed of a DC source, an inverter and a compensation network.

10. The method of claim 1, wherein the load further comprises a rectifier bridge and a power load connected to each other.