CN110858728B - Wireless energy transmission system and wireless energy transmission control method - Google Patents
Wireless energy transmission system and wireless energy transmission control method Download PDFInfo
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- CN110858728B CN110858728B CN201810973032.8A CN201810973032A CN110858728B CN 110858728 B CN110858728 B CN 110858728B CN 201810973032 A CN201810973032 A CN 201810973032A CN 110858728 B CN110858728 B CN 110858728B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
- H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
- H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
Abstract
The invention provides a wireless energy transmission system and an energy transmission method, which comprise n coil modules, wherein at least one of the n coil modules and the rest coil modules form a wireless energy transmission path at a specified resonant frequency based on magnetic coupling resonance, and if F is used, a wireless energy transmission path is formed between the n coil modules and the rest coil modules 123...n And representing the energy transmission coefficient of the wireless energy transmission path, wherein the following relation exists:
adjusting an equivalent resistance (R) in at least one coil module by controlling a dynamic impedance converter in the at least one coil module such that F 123...n At maximum, when said F 123...n And when the maximum energy transmission efficiency is reached, the comprehensive energy transmission efficiency of the wireless energy transmission channel is highest. Therefore, the wireless power transmission system based on magnetic coupling, which comprises a plurality of transmitting ends and/or receiving ends, can obtain good system energy transmission efficiency under the condition of not frequently adjusting the frequency.
Description
Technical Field
The invention relates to a far-field wireless energy transmission technology for converting electric energy into a magnetic field in a magnetic coupling mode and converting the magnetic field into electric energy at a receiving side after transmission, in particular to a wireless energy transmission system and a wireless energy transmission control method.
Background
Currently, technologies for wireless charging of mobile phones, watches, tablet computers, electric vehicles and the like are receiving wide attention. In recent years, wireless power transmission technology based on magnetic coupling has become a hot spot for research and industrial application. The principle of the wireless power transmission technology based on magnetic coupling is as follows: a high-frequency power supply is applied to the transmitting side coil, so that the transmitting side coil generates a high-frequency magnetic field under the excitation of the power supply, and the receiving side coil is coupled to generate current under the action of the high-frequency magnetic field, thereby realizing wireless power transmission.
A proximity wireless charging device based on a near field magnetic coupling technology has been put to practical use. For example, a load such as a mobile phone or a watch is placed on a charging dock, and the load is charged based on near-field magnetic coupling. However, the charging method based on the near-field coupling technology is still limited by many factors such as wires, distance, spatial position, etc., and still has the defect of insufficient convenience in use.
The inventors of the present invention wish to develop a technology that enables charging at a greater distance, for example, by placing the transmitting end of the incoming power supply somewhere in the room (e.g., a corner of the room, a roof, etc.), by which a terminal such as a receiving end (i.e., a load such as a cell phone, a walkable robot, a light-emitting lighting device, etc.) located in the room can be charged, which receiving end can be mobile and does not require that the receiving end must be located within a spatial range of, for example, about 10cm around the transmitting end. Namely: the invention provides further research on a magnetic coupling-based middle and far field power transmission technology.
As known to those skilled in the art, in the middle and far field transmission process based on magnetic coupling, the coupling coefficient k varies with the increase of the distance between the coupling coils (i.e., the transmission distance), and at the same time, the power transmission efficiency between the coupling coils varies, but it is considered that the transmission efficiency is relatively best in the case where the resonance frequency is the same as the natural frequency of each coupling coil (as shown in fig. 1). Specifically, if the natural frequency of the transmitting side coil is f 1 The natural frequency of the receiving side coil is f 2 Resonant frequency of the magnetically resonant system is f 0 Then f is 0 ＝f 1 ＝f 2 The system transmission efficiency is the best. However, due to the reduced resistance of the coupling system, the transmitting coil and the receiving coil will refract an equivalent resistance each other in the process of getting closer, so that there is a phenomenon of frequency splitting. Obtaining the resonant frequency f 0 The efficiency at the time is not the maximum efficiency point, but the maximum efficiency point is changed from one to 2, and therefore the frequency maximum point needs to be tracked, and the transmission-side frequency f1 or the reception-side frequency f2 needs to be adjusted to obtain the relative maximum frequency.
Therefore, in the prior art, there are some coupling coefficients k that vary with the coupling coefficient k (e.g., the coupling coefficient k varies due to the distance between the coupling coils, due to different coupling coil structuresResulting in a change of the coupling coefficient k, etc.) to adjust the resonance frequency f 0 To obtain maximum energy transmission efficiency (as in patent document 1); according to the resonant frequency f 0 The coupling coefficient of the transmitting side coil and the receiving side coil is adjusted (see patent document 2).
However, since the resonant circuit itself generates ohmic loss when transmitting energy, there is a skin effect, and it is difficult to adjust the frequency continuously and smoothly by adjusting the capacitance and the inductance, which is generally discrete, there is a limitation in adjusting the frequency, and it is difficult to achieve a constant maximum value of the frequency or efficiency within a certain range. Furthermore, when there are many transmitting ends and/or receiving ends, there is a difficulty in adjusting the coupling coefficient k or the resonant frequency f 0 In the case of (c). When such a wireless energy transfer system is used, for example, to charge a plurality of loads (mobile terminals such as mobile phones), there is a problem that the charging efficiency is not good as a whole.
Therefore, the present invention is intended to seek a technique capable of obtaining good energy transfer efficiency even in a case where a plurality of transmitting terminals and/or a plurality of receiving terminals participate in wireless power transfer based on magnetic coupling resonance at the same time.
Prior Art
Patent document 1: CN101682216A
Patent document 2: CN103414261A
Disclosure of Invention
In order to solve the problems in the prior art, the present invention provides a wireless energy transfer system and a wireless energy transfer control method, so that a wireless power transmission system including a plurality of transmitting terminals and/or receiving terminals and based on magnetic coupling can obtain a good system energy transmission efficiency without frequently adjusting the frequency.
In order to solve the technical problems, the invention adopts the following technical scheme.
The invention provides a wireless energy transfer system, which is characterized by comprising n coil modules, wherein each coil module comprises: a first coil electrically connected to an external power source or an external load; an impedance matching network electrically connected with the first coil for connecting with the first coilThe external power supply or the external load realizes impedance matching; a second coil magnetically coupled to the first coil; and a dynamic impedance converter electrically connected to the second coil, the dynamic impedance converter making the reactance of the second coil zero and changing the equivalent resistance (R) of the coil module, wherein at least one of the n coil modules and the remaining coil modules form a wireless energy transmission path at a predetermined resonance frequency based on magnetic coupling resonance, and if F is used 123..n Representing a reduced quality factor of said wireless energy transfer system, denoted F 123..n And the energy transmission coefficient of the wireless energy transmission channel is represented, and the following relation exists:
wherein n represents the number of coil modules in the system and is greater than or equal to 2; r n Representing the equivalent resistance in the nth coil module; l' represents a normalized reference self-inductance value of the self-inductance (L) of each coil module; τ l represents a normalized self-inductance fitting coefficient, and the numerical value is in the range of 1-5; m' represents a normalized reference mutual inductance value between the coil modules; tau m represents a normalized mutual inductance fitting coefficient, and the numerical value is in the range of 0-8; omega 0 Represents the resonance angular frequency of the system and satisfies ω 0 Where F denotes the prescribed system resonance frequency, and the equivalent resistance (R) in at least one of the coil modules is adjusted by controlling the dynamic impedance converter in the at least one coil module so that F is equal to F 123..n At maximum, when said F 123..n And when the maximum energy transmission efficiency is reached, the comprehensive energy transmission efficiency of the wireless energy transmission channel is highest.
In the above wireless energy transfer system, when the coil module is used as an energy transfer transmitting terminal, the first coil of the coil module is electrically connected to the external power supply, and the impedance matching network is used for implementing impedance matching with the external power supply; when the coil module is used as an energy transmission receiving end, the first coil of the coil module is electrically connected with the external load, and the impedance matching network is used for realizing impedance matching with the external load.
In the above wireless energy transfer system, preferably, the equivalent resistance (R) in at least one of the coil modules including the nth coil module is adjusted by controlling the dynamic impedance converter in the at least one coil module so that F is equal to F 123..n And maximum.
In the above wireless energy transfer system, τ l may be 1; τ m is 1 to 8.
The invention also provides a wireless energy transmission control method, which is characterized by comprising the step of establishing a wireless energy transmission path among n coil modules, wherein each coil module comprises the following steps: a first coil electrically connected to an external power source or an external load; the impedance matching network is electrically connected with the first coil and is used for realizing impedance matching with the external power supply or the external load; a second coil magnetically coupled to the first coil; and a dynamic impedance converter electrically connected to the second coil, the dynamic impedance converter being capable of changing an equivalent resistance (R) of the coil module while making a reactance of the second coil zero, wherein at least one of the n coil modules and the remaining coil modules form a wireless energy transmission path at a predetermined resonance frequency by magnetic coupling resonance, and Q is used if Q is used 123..n Representing a reduced quality factor of said wireless energy transfer channel, denoted F 123..n And the energy transmission coefficient of the wireless energy transmission path is expressed by the following relation:
wherein n represents the number of the coil modules and is more than or equal to 2;R n representing the equivalent resistance in the nth coil module; l' represents a normalized reference self-inductance value of the self-inductance (L) of each coil module; τ l represents a normalized self-inductance fitting coefficient, and the numerical value is in the range of 1-5; m' represents a normalized reference mutual inductance value between the coil modules; tau m represents a normalized mutual inductance fitting coefficient, and the numerical value is in the range of 0-8; omega 0 Represents the resonance angular frequency and satisfies omega 0 And =2 pi · f (expression 3), where f represents the predetermined system resonance frequency.
The control method further comprises the following steps: determining the number (n) of coil modules; determining the normalized reference self-inductance value (L ') and the normalized reference mutual inductance value (M'); selecting the self-inductance fitting coefficient (tau l) and the mutual inductance fitting coefficient (tau m); controlling the dynamic impedance transformer in at least one of the coil modules based on the relationship to adjust an equivalent resistance (R) in the at least one of the coil modules such that F 123..n At maximum, when said F 123..n And when the maximum energy transmission efficiency is reached, the comprehensive energy transmission efficiency of the wireless energy transmission channel is highest.
In the above wireless energy transfer control method, the method further includes an updating step, when the coil module is added to the wireless energy transfer path, the coil module is newly added as an updated nth coil module through the updating step, and the equivalent resistance (R) in at least one coil module including the updated nth coil module is adjusted by controlling the dynamic impedance converter in the at least one coil module, so that the F is obtained 123..n And max.
In the above wireless energy transfer control method, τ l may be 1; τ m is 1 to 8.
Effects of the invention
According to the technical scheme of the invention, for the wireless power transmission system based on magnetic coupling and comprising a plurality of transmitting terminals and/or receiving terminals, good system energy transmission efficiency can be obtained under the condition of not frequently adjusting the frequency, so that the system transmission performance is optimal. Therefore, the method can be effectively applied to a scene of simultaneously charging a plurality of loads, and can also be effectively applied to a scene of jointly charging the loads by combining a plurality of transmitting terminals.
Drawings
Fig. 1 is a graph showing the relationship between frequency and transmission efficiency at different coupling coefficients.
Fig. 2 is a schematic structural diagram of a wireless energy transfer system including an N-coil module.
Fig. 3 is a schematic structural diagram of a transmitting coil module in a wireless energy transmission system.
Fig. 4 is a schematic structural diagram of a receiving coil module in a wireless energy transmission system.
Fig. 5 is a schematic structural diagram of the wireless energy transfer system according to embodiment 1.
Fig. 6 is a three-dimensional graph showing a function of the wireless power transmission capability of embodiment 1.
Fig. 7 is a two-dimensional graph showing a function of the wireless energy transfer capability of embodiment 1.
Fig. 8 is a two-dimensional graph showing a function of the wireless power transmission capability of embodiment 1.
Fig. 9 is a schematic configuration diagram of the wireless energy transfer system according to embodiment 2.
Fig. 10 is a three-dimensional graph showing the function of the wireless energy transfer capability of example 2.
Fig. 11 is a two-dimensional graph showing a function of the wireless power transmission capability of embodiment 2.
Fig. 12 is a two-dimensional graph showing a function of the wireless power transmission capability of embodiment 2.
Fig. 13 is a schematic structural diagram of a wireless energy transfer system according to embodiment 3
Fig. 14 is a three-dimensional graph showing the function of the wireless energy transfer capability of example 3.
Fig. 15 is a two-dimensional graph showing a function of the wireless power transmission capability of embodiment 3.
Fig. 16 is a two-dimensional graph showing a function of the wireless power transmission capability of example 3.
Fig. 17 is a schematic structural diagram of a wireless energy transfer system according to embodiment 4
Fig. 18 is a functional three-dimensional graph showing the wireless energy transfer capability of example 4.
Fig. 19 is a two-dimensional graph showing a function of the wireless power transmission capability of embodiment 4.
Fig. 20 is a two-dimensional graph showing a function of the wireless power transmission capability of embodiment 4.
Fig. 21 is a three-dimensional graph showing the function of the wireless energy transfer capability of example 5.
Fig. 22 is a two-dimensional graph showing a function of the wireless power transmission capability of example 5.
Fig. 23 is a two-dimensional graph showing a function of the wireless power transmission capability of embodiment 5.
Detailed Description
The following describes in detail embodiments of the present invention with reference to the drawings.
[ constitution of Wireless energy Transmission System ]
FIG. 2 is a schematic structural diagram of a wireless energy transfer system including an N-coil module; fig. 3 is a schematic structural diagram of a transmitting coil module in a wireless energy transmission system; fig. 4 is a schematic structural diagram of a receiving coil module in a wireless energy transmission system.
As shown in fig. 2, the wireless energy transfer system of the present invention includes N coil modules L, each coil module L includes: a first coil C1 electrically connected to an external power source or an external load; the impedance matching network Z' is connected with the first coil C1 and used for realizing impedance matching with an external power supply or an external load; a second coil C2 magnetically coupled to the first coil C1; and a dynamic impedance converter Z electrically connected to the second coil C2, and capable of changing the equivalent resistance R of the coil module while making the reactance of the second coil C2 zero. At least one of the N coil modules resonates with the rest of the N coil modules at a predetermined resonant frequency f, so that a wireless energy transfer path is formed based on the magnetic coupling resonance.
The second coil C2 is also connected to a controllable on-off switch K, which is connected in series with the dynamic impedance transformer Z. The controllable on-off switch K is turned on or off under the control of a control unit (not shown), so that the coil module L is added or not added with an energy transmission path.
As shown in fig. 3, when the coil module L is used as a transmitting terminal, the first coil C1 is connected to an external power source. The external power supply is used as an energy source of the wireless energy transmission system, can be a power supply connected to a power grid, and can also be an energy storage device capable of being repeatedly charged and discharged. Its impedance matching network Z' is used to match the impedance of the power supply so that the reactance in the power supply system output impedance is 0. That is, when the impedance of the power supply system is expressed by the formula Z = R + jX, where Z is the impedance, R is the real impedance part, and X is the imaginary impedance part, X =0 is obtained.
As shown in fig. 4, when the coil module L is used as a receiving terminal, the first coil C1 is connected to an external load. The external load is, for example, a mobile phone, a robot, a heat generating device, or the like, which is a charging target. At this time, the impedance matching network Z' is used to match the receiving-end load impedance so that the reactance in the output impedance of the load is 0. That is, when the impedance of the load is expressed by the formula Z = R + jX, where Z is the impedance, R is the real impedance part, and X is the imaginary impedance part, X =0 is obtained.
The dynamic impedance transformer electrically connected to the second coil C2 can compensate the reactance of the system impedance of the coil block so that the reactance is 0. That is, if the system impedance of the coil block is expressed by the formula Z = R + jX, where Z is an impedance, R is a real impedance part, and X is an imaginary impedance part, X =0 is set. In addition, the dynamic impedance converter can also adjust the resistance, that is, can make the real impedance part R (resistance R) in the above system impedance formula Z = R + jX adjustable.
Energy transmission capability of wireless energy transmission system
In the prior art, for a four-coil structure (i.e. the case of the present invention comprising 2 coil modules), there is a quality factor Q of 4 coils required for obtaining good energy transfer effect 1 、Q 2 、 Q 3 、Q 4 All high design (Q if corresponding to the case of the invention comprising 2 coil modules 1 、Q 2 Respectively representing the quality factors of the coils C1 and C2 at the transmitting end; q 3 、Q 4 Representing the quality factor of the receiving side coils C2, C1, respectively). However, the desired technical effect of such a solution can only be achieved when the 4 coils are in a certain rest position. If the positions of the 4 coils are changed, the coupling coefficient K is changed, and the position of each coil is changedEquivalent Q (Q = ω) 0 L/R) value change, equivalent resistance R of each coil at high frequency n As well as may vary. At this time, with respect to the equivalent resistance R n The coupling reduced impedance R' should also be taken into account. I.e. for Q, for example 2 To speak, Q 2 ＝ω 0 L 2 /R 2 +R 3 ', wherein, ω 0 Representing the resonant frequency, L, of the system 2 Represents the inductance value, R, of the transmitting-end coil C2 2 Represents the equivalent resistance, R, of the transmitting-end coil C2 at high frequency 3 ' denotes a coupling reduced impedance of the receiving-end coil C2.
If the positions of the 4 coils are changed so that the energy transfer distance becomes longer, the coupling coefficient K becomes smaller, so that the energy transfer efficiency also decreases, and if it is desired to improve the energy transfer efficiency, it is necessary to improve Q within a certain range 2 Lowering Q 3 . However, as the energy transmission distance changes, it is converted to Q as described above 2 The internal resistance in (b) also changes and the capacity of energy transfer changes and is no longer optimal. Therefore, the problem to be solved by the present invention is to obtain the best energy transmission capability for the transmitting end coil and the receiving end coil in any positional relationship.
First, in the case where the positions of the transmitting end and the receiving end are not fixed, the positions, distances, and the like of the respective coupling coils are not fixed. In the case where there are a plurality of types of receiving terminals, the coil sizes and the like used for the receiving terminals may be different. The mutual inductance M is related to the size, position and distance of the coil, but the coil used by the user cannot be limited, so the invention adopts a means for adjusting the energy transmission efficiency of the system in a mode of being irrelevant to the change of M.
Further, since the impedance of each coil module is Z = R + jx, if jx =0, it is sufficient to pay attention to the resistance R of the coil module (i.e., the equivalent internal resistance of one coil module itself, which is not reflected).
For one-to-one example, the transmitting end and the receiving end transfer energy through a magnetic closed loop. The divergence at each point in this circular closed loop is 0. Then, from one of the points, the rest of the overall system is observedThe energy storage and consumption process between them can be described by a wooden barrel model. Namely Q 1 。。。 Q n Formed system Q 1～n The value is always less than the minimum of the preceding values. Thus, 1/Q 1～n Is equal to 1/Q 1 +1/Q 2 +。。。1/Q n . Substitution QN = Wl n /(R n +z’ n ). Thereby, the formula 1F is derived 123..n
If using F 123..n Representing a reduced quality factor of said wireless energy transfer system, denoted F 123..n And representing the energy transmission coefficient of the wireless energy transmission path, wherein the following relation exists:
wherein, the first and the second end of the pipe are connected with each other,
n represents the number of coil modules in the system and is more than or equal to 2;
R n representing the equivalent resistance in the nth coil module;
l' represents a normalized reference self-inductance value of the self-inductance (L) of each coil module;
τ l represents a normalized self-inductance fitting coefficient, and the numerical range of 1 to 5 is taken;
m' represents a normalized reference mutual inductance value between the coil modules,
tau m represents a normalized mutual inductance fitting coefficient, and the numerical range of 0 to 8 is taken;
ω 0 represents the resonance angular frequency of the system and satisfies omega 0 =2 pi · f, f denotes a prescribed system resonance frequency,
adjusting an equivalent resistance (R) in at least one of the coil modules by controlling the dynamic impedance transformer in the at least one of the coil modules such that F 123..n At the maximum, the number of the first,
when said F is 123..n And when the maximum energy transmission efficiency is reached, the comprehensive energy transmission efficiency of the wireless energy transmission channel is highest.
The core innovation of this patent is that F is utilized 123～n This parameter characterizes the wireless transmission efficiency (or, stated alternatively, the power and efficiency optimality) of the system, and the system performance is best when this system variable is at its maximum. F in the current state can be found only by adjusting the real impedance part R (n) of each coil module 123..n Is measured.
F 123..n Under different system states (such as different coil modules, different inter-group physical position relationships, and different numbers), the maximum value ranges are different, i.e., the optimal effects under different system states are also different. However, the present invention provides a method for finding the optimal value of the energy transmission efficiency of the system, which comprises the following steps: according to the above with respect to F 123..n Adjusting the real part of impedance R (n) of each coil block to F 123..n And max. The formula shows that the real part R (n) of the impedance can be adjusted, and the real part R (n) of the impedance is independent of the mutual inductance M.
[ example 1 ] A method for producing a polycarbonate
For a wireless energy transfer network of 2-coil modules as shown in FIG. 5, regarding F 123..n Becomes about F 12 The formula, namely:
for example, when the parameters of the actual system are:
ω 0 ＝2π·f＝2π·10 6 i.e. f =10 6 Hz；R 1 ＝0.1Ω；τm＝10 -6 ；τl＝5；L′＝10 -3 When obtaining F 12 With respect to R 2 And M', and drawing a function graph by Matlab to obtain a function graph (see FIGS. 6 to 8). As shown in FIGS. 6-8, with the change in the normalized mutual inductance value M', R is always present 2 Make F 12 The maximum value is taken. Further, as is clear from FIG. 6, F 12 Since the normalized mutual inductance value M' does not vary greatly, it depends on the spatial position, distance, and coilThe variation of mutual inductance M and M' caused by size does not greatly influence F 12 Peak value of (a). Therefore, the energy transfer capability of the system can be stably ensured.
[ example 2 ]
For the wireless energy transfer network with 3 coil modules as shown in fig. 9, 3 coil modules are placed in positions forming an equilateral triangle. With respect to F 123..n Becomes about F 123 The formula, namely:
for example, when the parameters of the actual system are:
ω 0 ＝2π·f＝2π·10 6 i.e. f =10 6 Hz；R 1 ＝0.1Ω；R 2 ＝0.1Ω；τm＝6；τl＝1；L′＝10 -3 When obtaining F 123 About R 3 And M', and drawing a function graph by Matlab to obtain a function graph (see FIGS. 10 to 12). As shown in FIGS. 10-12, with the change in the normalized mutual inductance value M', R is always present 3 Make F 123 The maximum value is taken. Further, as is clear from FIG. 10, F 123 Since the variation of the normalized mutual inductance value M 'is not severe, the variation of the mutual inductance value M and the mutual inductance value M' due to the spatial position, the distance, the coil size, and the like does not greatly affect F 123 Peak value of (a). Therefore, the energy transfer capability of the system can be stably ensured.
[ example 3 ] A method for producing a polycarbonate
For the wireless energy transfer network with 3 coil modules as shown in fig. 13, the 3 coil modules are placed in the position of an isosceles triangle. With respect to F 123..n Becomes about F 123 The formula, namely:
for example, when the parameters of the actual system are:
ω 0 ＝2π·f＝2π·10 6 i.e. f =10 6 Hz；R 1 ＝0.1Ω；R 2 ＝0.1Ω；τm＝1.7；τl＝1；L′＝10 -3 Then, obtain F 123 With respect to R 3 And M', and drawing a function graph by Matlab to obtain a function graph (see FIGS. 14 to 16). As shown in FIGS. 14-16, with the variation of the normalized mutual inductance value M', R is always present 3 Make F 123 A maximum value is obtained. Further, as is clear from FIG. 14, F 123 Since the variation of the normalized mutual inductance value M 'is not severe, the variation of the mutual inductance value M and the mutual inductance value M' due to the spatial position, the distance, the coil size, and the like does not greatly affect F 123 Peak value of (a). Therefore, the energy transfer capability of the system can be stably ensured.
[ example 4 ]
For the wireless energy transfer network with 4 coil modules as shown in fig. 17, the 4 coil modules are placed at the same distance from each other, that is, the connecting line between the 4 coil modules forms a regular rectangular pyramid, and the connecting line is the edge of the regular rectangular pyramid.
For the wireless energy transmission network with 4 coil modules, the coil modules are completely the same, and the position relationship is an isosceles triangle placement mode. Therefore, L can be assumed 1 ＝L 2 ＝L 3 ＝L 4 ＝L’， M 12 ＝M 21 ＝M 13 ＝M 31 ＝M 14 ＝M 41 ＝M 23 ＝M 32 ＝M 24 ＝M 42 ＝M 34 ＝M 43 ＝M’。
With respect to F 123..n Becomes about F 1234 The formula (c) of (a):
for example, when the parameters of the actual system are:
ω 0 ＝2π·f＝2π·10 6 i.e. f =10 6 Hz；R 1 ＝0.1Ω；R 2 ＝0.1Ω；R 3 ＝0.1Ω；τm＝8；τl＝1； L′＝10 -3 Then, obtain F 1234 About R 4 And M', and drawing a function graph by Matlab to obtain a function graph (see FIGS. 14 to 16). As shown in FIGS. 18-20, R is always present as the normalized mutual inductance value M' changes 4 Make F 1234 A maximum value is obtained. Further, as is clear from FIG. 18, F 1234 Since the variation of the normalized mutual inductance value M 'is not severe, the variation of the mutual inductance coefficient M and the mutual inductance value M' caused by the spatial position, the distance, the coil size and the like does not greatly influence F 1234 The peak value of (c). Therefore, the energy transfer capability of the system can be stably ensured.
[ example 5 ]
For a wireless energy transfer network including N (N is 2 or more) coil modules, the position models of the coil modules may be understood to include one or more of the position models of embodiments 1 to 4 described above.
For a wireless energy transfer network comprising N coil modules, finding F of the current system can be realized by adjusting R (N) of any coil module 123..n Is measured.
For example, for a wireless energy transfer network with 2 coil modules, the equivalent resistance R of the first or second coil module is adjusted under the condition that the physical position, the coil structure and the like are fixed 1 Or equivalent resistance R 2 All can make F 12 Reaching a maximum value (as shown in figures 21-23).
That is, for a wireless energy transfer network including N coil modules, each coil module can be arbitrarily numbered to satisfy the relationship with F 123..n N in the formula (1). Of course, the coil module newly added to the wireless energy transfer network may be always set as the nth one.
The specific embodiments of the present invention have been described above, but the embodiments do not limit the scope of the present invention. Those skilled in the art will appreciate that various modifications to the above described embodiments are also within the scope of the present invention.
Claims (6)
1. A wireless energy transfer system is characterized in that,
including a n coil module, each position between the coil module is variable, each the coil module includes:
a first coil electrically connected to an external power source or an external load;
the impedance matching network is electrically connected with the first coil and used for realizing impedance matching with the external power supply or the external load;
a second coil magnetically coupled to the first coil; and
a dynamic impedance converter electrically connected to the second coil, and capable of changing an equivalent resistance (R) of the coil module while making a reactance of the second coil zero,
at least one of the n coil modules and the rest coil modules form a wireless energy transfer path based on magnetic coupling resonance at a specified resonance frequency,
if it is used
Representing a reduced quality factor of said wireless energy transfer system
And representing the energy transmission coefficient of the wireless energy transmission path, wherein the following relation exists:
wherein the content of the first and second substances,
n represents the number of coil modules in the system and is more than or equal to 2;
R n representing the equivalent resistance in the nth coil module;
l' represents a normalized reference self-inductance value of the self-inductance (L) of each coil module;
τ l represents a normalized self-inductance fitting coefficient, and the numerical value is in the range of 1 to 5;
m' represents a normalized reference mutual inductance value between the coil modules,
τ m represents a normalized mutual inductance fitting coefficient, and the numerical value is in the range of 0 to 8;
ω 0 represents the resonance angular frequency of the system and satisfies
(formula 3) in the above-mentioned manner,
represents the prescribed system resonance frequency or frequencies,
adjusting an equivalent resistance (R) in at least one of the coil modules by controlling the dynamic impedance converter in the at least one of the coil modules such that the
At the maximum, the number of the first,
when said
And when the maximum energy transmission efficiency is reached, the comprehensive energy transmission efficiency of the wireless energy transmission channel is highest.
2. The wireless energy transfer system according to claim 1,
when the coil module is used as an energy transmission transmitting end, the first coil of the coil module is electrically connected with the external power supply, and the impedance matching network is used for realizing impedance matching with the external power supply;
when the coil module is used as an energy transmission receiving end, the first coil of the coil module is electrically connected with the external load, and the impedance matching network is used for realizing impedance matching with the external load.
3. The wireless energy transfer system according to claim 1,
τ l is 1; τ m is 1 to 8.
4. A wireless energy transmission control method is characterized in that,
including the step of establishing wireless energy transfer route between n coil module, the position between each coil module is variable, wherein, each coil module includes: a first coil electrically connected to an external power source or an external load; the impedance matching network is electrically connected with the first coil and is used for realizing impedance matching with the external power supply or the external load; a second coil magnetically coupled to the first coil; and a dynamic impedance converter electrically connected to the second coil, and capable of changing an equivalent resistance (R) of the coil module while making a reactance of the second coil zero,
at least one of the n coil modules and the rest coil modules form a wireless energy transfer path based on magnetic coupling resonance at a specified resonance frequency,
if it is used
A reduced quality factor representing the wireless energy transfer channel
And the energy transfer coefficient of the wireless energy transfer channel is represented, and the following relational expression exists:
wherein, the first and the second end of the pipe are connected with each other,
n represents the number of the coil modules and is more than or equal to 2;
R n representing the equivalent resistance in the nth coil module;
l' represents a normalized reference self-inductance value of the self-inductance (L) of each coil module;
τ l represents a normalized self-inductance fitting coefficient, and the numerical value is in a range of 1 to 5;
m' represents a normalized reference mutual inductance value between the coil modules,
τ m represents a normalized mutual inductance fitting coefficient, and the numerical value is in the range of 0 to 8;
ω 0 represents the resonance angular frequency and satisfies
(formula 3) in the above-mentioned manner,
represents the prescribed system resonance frequency or frequencies,
the control method further comprises the following steps:
determining the number (n) of coil modules;
determining the normalized reference self-inductance value (L ') and the normalized reference mutual-inductance value (M');
selecting the self-inductance fitting coefficient (tau l) and the mutual inductance fitting coefficient (tau m);
controlling the dynamic impedance transformer in at least one of the coil modules based on the relationship to adjust an equivalent resistance (R) in the at least one of the coil modules such that the
At the maximum, the number of the first,
when said
And when the maximum energy transmission efficiency is reached, the comprehensive energy transmission efficiency of the wireless energy transmission channel is highest.
5. The wireless energy transfer control method according to claim 4, further comprising an updating step of, when another coil module is added to the wireless energy transfer path, making the newly added coil module as an updated nth coil module,
adjusting an equivalent resistance (R) in at least one coil module including the updated nth coil module by controlling the dynamic impedance converter in the at least one coil module such that the equivalent resistance (R) is adjusted
And maximum.
6. The wireless energy transfer control method according to claim 4,
τ l is 1; τ m is 1 to 8.
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