CN106340975A - Wireless electric energy transmission circuit and design method - Google Patents

Abstract

The invention discloses a wireless electric energy transmission circuit. The wireless electric energy transmission circuit includes a power source module, an energy transmitting end, an energy receiving end, a loose coupling transformer, a primary side resonant capacitor and a secondary side resonant capacitor; the energy transmitting end is connected with the power source module; the energy receiving end is connected with the energy transmitting end and supplies power to loads; the energy transmitting end includes an inversion circuit and an immittance converter which are in circuit connection sequentially, wherein the inversion circuit is connected with the power source module; the loose coupling transformer includes a primary side transmitting coil and at least one secondary receiving coil, wherein the primary side transmitting coil is arranged on the energy transmitting end and is connected with the immittance converter, and the secondary receiving coil is arranged at the energy receiving end and is connected with corresponding loads through a rectifying circuit; the primary side resonant capacitor is connected in series with the primary side transmitting coil; and the secondary side resonant capacitor is connected in series with the secondary receiving coils. The invention also discloses a design method of the wireless electric energy transmission circuit. The wireless electric energy transmission circuit of the invention is an immittance converter principle-based improved circuit. With the circuit adopted, the output capacity and output voltage stability of the loose coupling transformer can be improved.

Description

A kind of wireless power transmission circuit and its method for designing

Technical field

The present invention relates to circuit design field is and in particular to a kind of wireless power transmission circuit and its method for designing.

Background technology

The artificial spacecraft system run on space orbit is referred to as " in-orbit system " or " space system ", defends including in-orbit Star, airship, space shuttle, space station (laboratory), space probe and space telescope etc..In-orbit system often runs into following Several predicaments: spacecraft on-orbit fault is generally only that individual part goes wrong, whole star loss from spoilage is too big；Disposably portable Consumable goodss are limited and are difficult to consume flowing material on supply spacecraft.

In-orbit service, with maintainable technology on-orbit as representative can settle the matter once and for all, and therefore, is main with maintainable technology on-orbit The in-orbit service, aircraft of task is paid close attention to by much countries, and in the last few years, in-orbit service, technology is rapidly developed.In-orbit Energy recharge is an important content of maintainable technology on-orbit, and in-orbit energy recharge is divided into two ways: the replacing of in-orbit energy module With in-orbit energy recharge.For some average lifes, spacecraft that is short and replacing high cost, can be had by in-orbit energy recharge Effect improves the life-span of spacecraft, significant.

Wireless power transmission technology has convenient and swift, safe and reliable feature, is increasingly taken seriously in space industry, Especially in terms of the in-orbit energy recharge of aircraft, it is a kind of effective solution, as shown in figure 1, maintenance service spacecraft system System passes through the receiving coil of the transmitting coil of energy radiating circuit to the energy acceptance circuit accepting maintenance service Space Vehicle System Transmission energy.But, existing radio energy transmission system method for designing is complicated, and the parameter difficulty of matching of resonance circuit is big, defeated Go out voltage pulsation big, output is unstable.Therefore, existing designing technique is applied to the wireless power transmission system of spacecraft System, certainly will can not obtain the result of satisfaction.

The wireless power transmission power that maintainable technology on-orbit power-supply system requires is larger, generally higher than 1kw, and wireless transmission distance is relatively Far, generally higher than 30cm, for ensureing maintainable technology on-orbit power work reliability, requires the output electricity of radio energy transmission system simultaneously Pressing element has the characteristics that not with load change.As shown in Fig. 2 adopting the radio energy transmission system of serial or parallel connection resonant network no Method meets above-mentioned requirements.

Content of the invention

It is an object of the invention to provide a kind of wireless power transmission circuit and its method for designing, former based on immittance converter The improved circuit of reason, strengthens the fan-out capability of loosely coupled transformer and the purpose of output voltage stability to reach, improves former The frequency characteristic of side series connection-secondary tandem type wireless power transmission resonant network, strengthens wireless transmitting system in lower coupling coefficient When output voltage stability so that the more preferable maintainable technology on-orbit power-supply system and unified wireless of must being applied to of wireless power transmission technology Charging platform.

In order to achieve the above object, the present invention is achieved through the following technical solutions: a kind of wireless power transmission circuit, and it is special Point is to comprise:

Power module, for providing electric energy, described power module comprise an industrial frequency rectifying circuit electrically connecting with city and Dc-link capacitance with industrial frequency rectifying circuit in parallel；

Energy transmitting terminal, is connected with described power module, for sending the electric energy of power module in a wireless form；

Energy acceptance end, is connected with described energy transmitting terminal, for receiving the electric energy that energy transmitting terminal sends, and to load Power supply；

Described energy transmitting terminal comprises inverter circuit and the immittance converter that circuit successively connects, described inverter circuit It is connected with described power module；

Loosely coupled transformer, comprises a former limit transmitting coil, and described former limit transmitting coil is arranged on energy transmitting terminal, with Described immittance converter connects；At least one secondary receiving coil, described secondary receiving coil is arranged on energy acceptance end, passes through Rectification circuit connects to corresponding load；

Former limit resonant capacitance, is connected with described former limit transmitting coil；

Secondary resonant capacitance, is connected with described secondary receiving coil；Wherein

Loosely coupled transformer, former limit resonant capacitance and secondary resonant capacitance constitute a resonant network.

Described wireless power transmission circuit also comprises a detection and protection circuit, described detection and protection circuit circuit It is connected between industrial frequency rectifying circuit and dc-link capacitance, for detecting dc-link capacitance voltage.

Described wireless power transmission circuit also comprises a commutation of load filtering and protection circuit, and described commutation of load is filtered Involve protection circuit to be electrically connected between rectification circuit and load.

Described wireless power transmission circuit also comprises a near-field communication circuit, and described near-field communication circuit comprises in pairs Signal transmitting and receiving circuit, wherein, data transmitting terminal is arranged on secondary receiving coil side, and data receiver is arranged on former limit emission lines Circle side, for obtaining the unpaired message that load accesses.

Described immittance converter is series connection lcl type immittance converter, and described immittance converter comprises first connecting Series inductance and the second series inductance, and the shunt capacitance in parallel with described first series inductance.

A kind of method for designing of wireless power transmission circuit described above, is characterized in, for maintainable technology on-orbit power-supply system Non-contact power supply, comprise the steps of

S1, according to maintainable technology on-orbit power-supply system to former limit transmitting coil diameter, secondary receiving coil diameter, be wirelessly transferred work( Rate and the requirement of transmission range, calculate loosely coupled transformer parameter, that is, determine loosely coupled transformer the former limit transmitting coil number of turn, Secondary receives line coil turn, former limit transmitting coil inductance value, secondary reception line coil inductance and the mutual inductance value of former secondary；

S2, the equivalent resistance according to load and the mutual inductance value of former secondary, are calculated the resonant frequency of immittance converter；

S3, the input voltage value according to power module and maintainable technology on-orbit power-supply system predeterminated voltage output valve, are calculated The output voltage gain value of resonant network；

S4, the resonant frequency of the output voltage gain value according to resonant network, the mutual inductance value of former secondary and immittance converter, meter The parameter to immittance converter calculated；

S5, the resonant frequency according to former limit transmitting coil inductance value and immittance converter, are calculated former limit resonant capacitance Capacitance, receive the resonant frequency of line coil inductance and immittance converter according to secondary, be calculated secondary resonant capacitance Capacitance；

S6, the efficiency of transmission of calculating resonant network, if meeting Preset Transfer efficiency value, complete wireless power transmission circuit Design, such as otherwise return to step s1, redefine loosely coupled transformer parameter.

Described step s4 comprises:

S4.1, the resonant frequency of the output voltage gain value according to resonant network, the mutual inductance value of former secondary and immittance converter, It is calculated the characteristic impedance value of immittance converter；

S4.2, according to the characteristic impedance value of immittance converter and the resonant frequency of immittance converter, be calculated impedance become The inductance value of the first series inductance of parallel operation and the capacitance of shunt capacitance；

S4.3, the inductance value according to the first series inductance of the immittance converter of immittance converter, are calculated impedance and become The inductance value of the second series inductance of parallel operation.

In described step s1, former limit inductance value is equal with secondary inductance value；In described step s4.3, immittance converter The inductance value of the first series inductance equal with the inductance value of the second series inductance.

A kind of method for designing of wireless power transmission circuit described above, is characterized in, puts down for a unified wireless charging Platform is powered to multiple low-power equipments, comprises the steps of

Step one, according to unified wireless charging platform between through-put power, former limit transmitting coil and secondary receiving coil The requirement of distance, determines the inductance value of former limit transmitting coil and the inductance value of multiple secondary receiving coil；

Step 2, the bearing power according to multiple low-power equipments, determine the input current of former limit transmitting coil；

Step 3, the input current according to former limit transmitting coil, the input voltage value of power module and switching frequency, calculate Obtain the characteristic impedance of immittance converter；

Step 4, the characteristic impedance according to immittance converter and switching frequency, are calculated the series electrical of immittance converter The inductance value of sense and the capacitance of shunt capacitance；

Step 5, according to former limit transmitting coil inductance value and switching frequency, obtain the capacitance of former limit resonant capacitance；

Step 6, the bearing power according to multiple low-power equipments, the inductance value of multiple secondary receiving coil and switch frequency Rate, is calculated the capacitance of secondary resonant capacitance, has completed the design of wireless power transmission circuit.

A kind of present invention wireless power transmission circuit and its method for designing compared with prior art have the advantage that this The electric current of bright former limit transmitting coil does not change with the change of load resistance, and output voltage does not change with load and changes；This Invention is particularly well-suited to remote, the invalid electric energy transmission system of lower coupling coefficient, has higher output voltage stability；This The circuit theory of invention is clear, method for designing is simple；The circuit of the present invention and method for designing are simultaneously applicable to multi load output Radio energy transmission system.

Brief description

Fig. 1 is maintainable technology on-orbit power-supply system schematic diagram of the prior art；

Fig. 2 is a kind of wireless power transmission circuit diagram of the prior art；

Fig. 3 is a kind of wireless power transmission circuit diagram of the present invention；

Fig. 4 is Central Plains of the present invention edge emitting coil constant-current characteristicses schematic diagram；

Fig. 5 is resonant network output voltage characteristic schematic diagram in the present invention.

Specific embodiment

Below in conjunction with accompanying drawing, by describing a preferably specific embodiment in detail, the present invention is further elaborated.

The present invention is lcl type impedance of connecting before series connection-series compensation type wireless power transmission circuit in the prior art Changer, as shown in figure 3, a kind of wireless power transmission circuit, comprises: power module, for providing electric energy, described power supply mould Block comprises an industrial frequency rectifying circuit electrically connecting with city and the dc-link capacitance c with industrial frequency rectifying circuit in parallel_f1；Energy is launched End, is connected with described power module, for sending the electric energy of power module in a wireless form；Energy acceptance end, with described energy Amount transmitting terminal connects, and for receiving the electric energy that energy transmitting terminal sends, and powers to load r；Described energy transmitting terminal comprises Circuit connects successively inverter circuit ui and immittance converter lcl, described inverter circuit ui is connected with described power module；Pine Coupling transformer, comprises a former limit transmitting coil l₁, described former limit transmitting coil l₁It is arranged on energy transmitting terminal, lead with described Resistance parallel operation lcl connects；At least one secondary receiving coil l₂, described secondary receiving coil l₂It is arranged on energy acceptance end, pass through Rectification circuit u connects to corresponding load r；Former limit resonant capacitance c₁, with described former limit transmitting coil l₁Series connection；Secondary resonance Electric capacity c₂, with described secondary receiving coil l₂Series connection；Wherein, loosely coupled transformer, former limit resonant capacitance c₁And secondary resonance electricity Hold c₂Constitute a resonant network ss；Preferably, described immittance converter is series connection lcl type immittance converter, described impedance Changer comprises the first series inductance l connected_s1With the second series inductance l_s2, and in parallel simultaneously with described first series inductance Connection electric capacity c_p.

The principle of circuit of the present invention is impedance mapping function by immittance converter so that the former limit of loosely coupled transformer There is Constant current input, as shown in figure 4, thus strengthening the power delivery capabilities of loosely coupled transformer and output voltage Stability, such as Fig. 5.

In the present embodiment, described wireless power transmission circuit also comprises a detection and protection circuit, described detection And protection circuit is electrically connected between industrial frequency rectifying circuit and dc-link capacitance, for detecting dc-link capacitance voltage, When occurring over-pressed or under-voltage, circuit is protected.

In the present embodiment, described wireless power transmission circuit also comprises a commutation of load filtering and protection circuit, institute The commutation of load filtering stated and protection circuit are electrically connected between rectification circuit and load, when there are excessively stream or short-circuit conditions Circuit is protected.

In the present embodiment, described wireless power transmission circuit also comprises a near-field communication circuit, and described near field leads to Letter circuit comprises pair signals transmission circuit, and wherein, data transmitting terminal is arranged on secondary receiving coil side, and data receiver sets Put in former limit transmitting coil side, for obtaining the unpaired message that load accesses.

In conjunction with above-mentioned wireless power transmission circuit, the invention also discloses a kind of design side of wireless power transmission circuit Method, for the non-contact power supply of maintainable technology on-orbit power-supply system, comprises the steps of

S1, according to maintainable technology on-orbit power-supply system to former limit transmitting coil diameter, secondary receiving coil diameter, be wirelessly transferred work( Rate and the requirement of transmission range, calculate loosely coupled transformer parameter, that is, determine loosely coupled transformer the former limit transmitting coil number of turn, Secondary receives line coil turn, former limit transmitting coil inductance value, secondary reception line coil inductance and the mutual inductance value of former secondary.

The output gain of resonant network can be by changing z₀With ω₀, the ratio of m is worth to, therefore, here by l₁And l₂Ratio Value be set to consistent it may be assumed that

l₁=l₂

In formula, l₁Represent former limit transmitting coil inductance value, l₂Represent secondary receiving coil inductance value.

S2, the equivalent resistance r according to load_acAnd mutual inductance value m of former secondary, it is calculated the resonant frequency of immittance converter ω₀；

${\mathrm{\ω}}_0=\frac{r_{ac}}{m}$

In formula, ω₀Represent the resonant frequency of immittance converter, r_acRepresent the equivalent resistance of load,

R represents the resistance value of load, and m represents the mutual inductance value of former secondary.

S3, the input voltage value according to power module and maintainable technology on-orbit power-supply system predeterminated voltage output valve, are calculated The output voltage gain value of resonant network.

$m_v=\frac{v_o}{v_{dc}}$

In formula, m_vRepresent the output voltage gain value of resonant network, v_oRepresent the output of maintainable technology on-orbit power-supply system predeterminated voltage Value, v_dcRepresent the input voltage value of power module.

S4, the resonant frequency of the output voltage gain value according to resonant network, the mutual inductance value of former secondary and immittance converter, meter The parameter to immittance converter calculated.

When determining the parameter of immittance converter, the value of the series inductance of immittance converter and the value of shunt capacitance will meet Following condition:

$\left\{\begin{array}{c}{l}_{s1}=l_{s2}=l\\ c_p=c\end{array}\right.$

In order to whole circuit is all in the working condition of resonance, the resonant frequency of immittance converter, former limit transmitting coil The resonant frequency of resonant frequency and secondary receiving coil will be consistent, therefore when designing circuit resonant element parameter, simultaneously Also to meet following condition:

${\mathrm{\ω}}_0=1/\sqrt{lc}=1/\sqrt{l_1{c}_1}=1/\sqrt{l_2{c}_2}$

Under circuit meets conditions above, the impedance expression of the resonant network based on immittance converter principle is as follows:

$z_{in}\left({\mathrm{\ω}}_0\right)={\left(\frac{z_0}{{\mathrm{\ω}}_{0}m}\right)}^2{r}_{ac}$

In this case, resonant network output voltage gain and the characteristic impedance of immittance converter are inversely proportional to and loose coupling The mutual inductance of transformator is directly proportional, as follows:

$m_v=\frac{{\mathrm{\ω}}_{0}m}{z_0}$

S4.1, the resonant frequency of the output voltage gain value according to resonant network, the mutual inductance value of former secondary and immittance converter, It is calculated the characteristic impedance value of immittance converter.

$z_0=\frac{{\mathrm{\ω}}_{0}m}{m_v}$

In formula, z₀Represent the characteristic impedance value of immittance converter, m_vRepresent the output voltage gain value of resonant network, ω₀Table Show the resonant frequency of immittance converter, m represents the mutual inductance value of former secondary.

S4.2, according to the characteristic impedance value of immittance converter and the resonant frequency of immittance converter, be calculated impedance become The inductance value of the first series inductance of parallel operation and the capacitance of shunt capacitance.

$\left\{\begin{array}{c}{z}_0=\sqrt{\frac{l_{s1}}{c_p}}\\ {\mathrm{\ω}}_0=\frac{1}{\sqrt{l_{s1}{c}_p}}\end{array}\right.$

In formula, z₀Represent the characteristic impedance value of immittance converter, l_s1Represent the electricity of the first series inductance of immittance converter Inductance value, ω₀Represent the resonant frequency of immittance converter, c_pRepresent the capacitance of the shunt capacitance of immittance converter.

S4.3, the inductance value according to the first series inductance of the immittance converter of immittance converter, are calculated impedance and become The inductance value of the second series inductance of parallel operation.

l_s2=l_s1

In formula, l_s1Represent the inductance value of the first series inductance of immittance converter, l_s2Represent the second string of immittance converter The inductance value of connection inductance.

S5, the resonant frequency according to former limit transmitting coil inductance value and immittance converter, are calculated former limit resonant capacitance Capacitance, receive the resonant frequency of line coil inductance and immittance converter according to secondary, be calculated secondary resonant capacitance Capacitance.

$\left\{\begin{array}{c}{c}_1=\frac{1}{{{\mathrm{\ω}}_0}^2{l}_1}\\ c_2=\frac{1}{{{\mathrm{\ω}}_0}^2{l}_2}\end{array}\right.$

In formula, c₁Represent the capacitance of former limit resonant capacitance, ω₀Represent the resonant frequency of immittance converter, l₁Represent former limit Transmitting coil inductance value, l₂Represent secondary receiving coil inductance value.

S6, the efficiency of transmission of calculating resonant network, if meeting Preset Transfer efficiency value, complete wireless power transmission circuit Design, such as otherwise return to step s1, redefine loosely coupled transformer parameter.

A kind of method for designing of the wireless power transmission circuit as described in any one claim as Claims 1 to 5, its It is characterised by, power to multiple low-power equipments for a unified wireless charging platform, unified wireless charging platform is mainly face To the small-power power supply unit such as mobile phone, panel computer, notebook computer, microphone, pda, display.With maintainable technology on-orbit power-supply system Compare, the particularity of unified wireless charging platform is, its load is multiple and output is less.Therefore, based on unification The method for designing of the radio energy transmission system of wireless charging platform is otherwise varied with maintainable technology on-orbit power-supply system, and concrete steps are such as Under:

Step one, according to unified wireless charging platform between through-put power, former limit transmitting coil and secondary receiving coil The requirement of distance, determines the inductance value of former limit transmitting coil and the inductance value of multiple secondary receiving coil；

Step 2, the bearing power according to multiple low-power equipments, determine the input current of former limit transmitting coil；

Step 3, the input current according to former limit transmitting coil, the input voltage value of power module and switching frequency, calculate Obtain the characteristic impedance of immittance converter；

Step 4, the characteristic impedance according to immittance converter and switching frequency, are calculated the series electrical of immittance converter The inductance value of sense and the capacitance of shunt capacitance；

Step 5, according to former limit transmitting coil inductance value and switching frequency, obtain the capacitance of former limit resonant capacitance；

Step 6, the bearing power according to multiple low-power equipments, the inductance value of multiple secondary receiving coil and switch frequency Rate, is calculated the capacitance of secondary resonant capacitance, has completed the design of wireless power transmission circuit.

Compare with traditional design method, based on the wireless power transmission electricity designed by circuit design method proposed by the present invention Road has higher safety, for example, the fault if output loading is short-circuited, the danger of high pressure is not had at energy acceptance end； There is large range of displacement, the fault that energy transmitting terminal will not be short-circuited in former limit transmitting coil and breadths receiving coil.

Although present disclosure has been made to be discussed in detail by above preferred embodiment, but it should be appreciated that above-mentioned Description is not considered as limitation of the present invention.After those skilled in the art have read the above, for the present invention's Multiple modifications and substitutions all will be apparent from.Therefore, protection scope of the present invention should be limited to the appended claims.

Claims (9)

1. a kind of wireless power transmission circuit is it is characterised in that comprise:

Power module, for providing electric energy, described power module comprises an industrial frequency rectifying circuit electrically connecting with city and and work Frequency rectification circuit dc-link capacitance in parallel；

Energy transmitting terminal, is connected with described power module, for sending the electric energy of power module in a wireless form；

Energy acceptance end, is connected with described energy transmitting terminal, for receiving the electric energy that energy transmitting terminal sends, and supplies to load Electricity；

Described energy transmitting terminal comprises inverter circuit and immittance converter, described inverter circuit and the institute that circuit connects successively State power module to connect；

Loosely coupled transformer, comprises a former limit transmitting coil, and described former limit transmitting coil is arranged on energy transmitting terminal, and described Immittance converter connects；At least one secondary receiving coil, described secondary receiving coil is arranged on energy acceptance end, by rectification Circuit connects to corresponding load；

Former limit resonant capacitance, is connected with described former limit transmitting coil；

Secondary resonant capacitance, is connected with described secondary receiving coil；Wherein

Loosely coupled transformer, former limit resonant capacitance and secondary resonant capacitance constitute a resonant network.

2. wireless power transmission circuit as claimed in claim 1 is it is characterised in that comprise a detection and protection electricity further Road, described detection and protection circuit are electrically connected between industrial frequency rectifying circuit and dc-link capacitance, for detecting direct current Bus capacitor voltage.

3. wireless power transmission circuit as claimed in claim 1 it is characterised in that comprise further one commutation of load filtering and Protection circuit, described commutation of load filtering and protection circuit are electrically connected between rectification circuit and load.

4. wireless power transmission circuit as claimed in claim 1 is it is characterised in that comprise a near-field communication circuit further, Described near-field communication circuit comprises pair signals transmission circuit, and wherein, data transmitting terminal is arranged on secondary receiving coil side, Data receiver is arranged on former limit transmitting coil side, for obtaining the unpaired message that load accesses.

5. wireless power transmission circuit as claimed in claim 1 is it is characterised in that described immittance converter is series connection lcl Type immittance converter, described immittance converter comprises the first series inductance and the second series inductance connected, and with described the The shunt capacitance of one series connection inductance in parallel.

6. a kind of method for designing of wireless power transmission circuit as claimed in claim 5 is it is characterised in that be used for maintainable technology on-orbit The non-contact power supply of power-supply system, comprises the steps of

S1, according to maintainable technology on-orbit power-supply system to former limit transmitting coil diameter, secondary receiving coil diameter, wireless transmitted power and The requirement of transmission range, calculates loosely coupled transformer parameter, that is, determine the former limit transmitting coil number of turn, the secondary of loosely coupled transformer Receive line coil turn, former limit transmitting coil inductance value, secondary reception line coil inductance and the mutual inductance value of former secondary；

S2, the equivalent resistance according to load and the mutual inductance value of former secondary, are calculated the resonant frequency of immittance converter；

S3, the input voltage value according to power module and maintainable technology on-orbit power-supply system predeterminated voltage output valve, are calculated resonance The output voltage gain value of network；

S4, the resonant frequency of the output voltage gain value according to resonant network, the mutual inductance value of former secondary and immittance converter, calculating Parameter to immittance converter；

S5, the resonant frequency according to former limit transmitting coil inductance value and immittance converter, are calculated the electricity of former limit resonant capacitance Capacitance, receives the resonant frequency of line coil inductance and immittance converter, is calculated the electricity of secondary resonant capacitance according to secondary Capacitance；

S6, the efficiency of transmission of calculating resonant network, if meeting Preset Transfer efficiency value, complete setting of wireless power transmission circuit Meter, such as otherwise return to step s1, redefine loosely coupled transformer parameter.

7. the method for designing of wireless power transmission circuit as claimed in claim 6 is it is characterised in that described step s4 bag Contain:

S4.1, the resonant frequency of the output voltage gain value according to resonant network, the mutual inductance value of former secondary and immittance converter, calculate Obtain the characteristic impedance value of immittance converter；

S4.2, according to the characteristic impedance value of immittance converter and the resonant frequency of immittance converter, be calculated immittance converter The inductance value of the first series inductance and shunt capacitance capacitance；

S4.3, the inductance value according to the first series inductance of the immittance converter of immittance converter, are calculated immittance converter The second series inductance inductance value.

8. the method for designing of wireless power transmission circuit as claimed in claim 7 is it is characterised in that in described step s1, Former limit inductance value is equal with secondary inductance value；In described step s4.3, the inductance value of the first series inductance of immittance converter Equal with the inductance value of the second series inductance.

9. a kind of method for designing of the wireless power transmission circuit as described in claim 1 ~ 5 any one claim, it is special Levy and be, power to multiple low-power equipments for a unified wireless charging platform, comprise the steps of

Step one, according to unified wireless charging platform to distance between through-put power, former limit transmitting coil and secondary receiving coil Requirement, determine the inductance value of former limit transmitting coil and the inductance value of multiple secondary receiving coil；

Step 2, the bearing power according to multiple low-power equipments, determine the input current of former limit transmitting coil；

Step 3, the input current according to former limit transmitting coil, the input voltage value of power module and switching frequency, are calculated The characteristic impedance of immittance converter；

Step 4, the characteristic impedance according to immittance converter and switching frequency, are calculated the series inductance of immittance converter Inductance value and the capacitance of shunt capacitance；

Step 5, according to former limit transmitting coil inductance value and switching frequency, obtain the capacitance of former limit resonant capacitance；

Step 6, the bearing power according to multiple low-power equipments, the inductance value of multiple secondary receiving coil and switching frequency, meter Calculate the capacitance obtaining secondary resonant capacitance, complete the design of wireless power transmission circuit.