CN105186646A - Dynamic wireless charging apparatus and parameter acquiring method thereof - Google Patents

Abstract

The invention discloses a dynamic wireless charging apparatus and a parameter acquiring method thereof. The dynamic wireless charging apparatus comprises an energy emitting module and an energy receiving module. The energy emitting module comprises a high-frequency inversion unit, an LC filter unit, a first compensation unit, and a power emitting coil which are successively connected. The high-frequency inversion unit converts DC power into high-frequency AC power. After the high-frequency AC power is adjusted by the LC filter unit and the first compensation unit, energy is emitted in a high-frequency magnetic field coupling mode. The energy receiving module comprises a power receiving coil, a second compensation unit, and an uncontrolled rectification unit which are successively connected, and converts received high-frequency AC power into DC power supplied to a load. The dynamic wireless charging apparatus may automatically adjust the current of a primary-side power coil according to the mutual inductance coupling degree of the power coil so as to obtain a characteristic maintaining stable output power, is suitable for dynamic wireless charging application occasions with a wide bias, and has high transmission efficiency and a soft switch characteristic. In addition, compensation topology provides a primary side inversion power supply with a zero-load current-limiting protection function.

Description

A kind of device for dynamic radio charging and parameter acquiring method thereof

Technical field

The invention belongs to wireless power transmission technical field, relate to a kind of for wide deviation range dynamic radio power transmitting device and parameter acquiring method thereof, being applicable to transmission range has certain deviation scope and through-put power to have the wireless charging occasion of certain stability requirement.

Background technology

In recent years, wireless power transmission technology (WirelessPowerTransfer, WPT) and electric vehicle engineering (ElectricVehicle, EV) achieve develop rapidly.Magnetic coupling wireless power transmission technology is by the high-frequency alternating magnetic field coupling transferring energy between power dispatch coil, it is the best wireless power transmission technology of development prospect, be widely applied at low power portable electric appts, such as mobile phone, cardiac pacemaker etc.Along with the further raising of through-put power and efficiency, magnetic coupling wireless power transmission technology successfully realizes the state type wireless charging of electric automobile, through-put power reaches 10kW, and efficiency of transmission reaches 92%, likely replaces traditional conduction-type charging modes in not far future.Electric automobile runs into the problem that single charge distance travelled is not enough and charging is difficult that electrokinetic cell bottleneck brings in the process of introducing to the market.In order to solve electric automobile power battery bottleneck further, dynamic radio charging scheme is suggested.Dynamic radio charging modes imagination lays coil chain under carriage way, uninterruptedly charges to the electric automobile in travelling, thus effectively extends distance travelled.In dynamic radio charging process, vehicle-mounted load itself works, and in order to ensure supply load and leave certain energy storage surplus and make business efficiency reach optimum, dynamic radio charging system should work with the nominal transmission power that can obtain in the moment.Therefore, when dynamic radio charging system must ensure that the Mutual Inductance Coupling coefficient of former secondary power coil changes within the specific limits, through-put power can not fluctuate widely with offset distance change, but will keep stable transfer state, namely has anti-excursion capability.

In order to increase effective deviation range of WPT system, generally from magnetic coupling and former limit compensation topology two aspect design improvement.By the transformation to magnetic coupling, Mutual Inductance Coupling coefficient is made to keep fluctuating more among a small circle in wider deviation range.On the other hand some high-order compensation topologys with good characteristic are suggested.Such as former limit LCL type compensation topology, because it has good constant-current source characteristic, makes regulation and control secondary become simple, adopts more in WPT system.Patent CN201310571308 " a kind of bilateral LCC compensation topology for wireless power transmission and tuning methods thereof " proposes a kind of LCCL compensation topology on the basis of LCL topology, on the basis of LCL type compensation topology, add a building-out capacitor, object for by compensation topology be tuned to perceptual region to realize zero voltage switch (ZeroVoltageSwitching, ZVS).But the through-put power of this compensation topology declines rapidly along with the increase of offset distance, cause electric automobile strictly must aim at traveling lane in the process of moving, be limited in less deviation range and travel.This will propose requirements at the higher level to electric vehicle driver, can reduce the practicality of dynamic radio charging.

Summary of the invention

For the defect of prior art, the object of the present invention is to provide a kind of device for dynamic radio charging and parameter acquiring method thereof, easily with offset distance change, big ups and downs cause the problem of the anti-excursion capability deficiency of existing compensation topology due to through-put power in existing wireless power transmission systems to be intended to solution.

For achieving the above object, the invention provides a kind of device for dynamic radio charging, comprise energy transmitter module and energy acceptance module; Described energy transmitter module comprises the high-frequency inversion unit, LC filter unit, the first compensating unit and the power transmit coils that connect successively; High-frequency inversion unit is used for carrying out inversion process and output high voltage square wave V to the direct voltage of outside input _ab, described LC filter unit is used for high frequency voltage square wave V described in filtering _abin harmonic components, the mode that power transmit coils is used for the high frequency voltage square wave after is after filtering coupled according to high frequency magnetic field is launched; Described first compensating unit is used for regulating the electric current of described power transmit coils, reduces the fluctuation of through-put power with offset distance; Energy acceptance module comprises the power receiving coil, the second compensating unit and the uncontrollable rectifier unit that connect successively; The power that power receiving coil is launched for receiving described power transmit coils; Described second compensating unit, for compensating the leakage inductance of described power receiving coil, makes only to transmit active power between described power transmit coils and described power receiving coil; It is direct current that described uncontrollable rectifier unit is used for the high-frequency ac electric rectification of reception, and supply load.

Further, the first compensating unit comprises the first building-out capacitor _,second building-out capacitor and the 3rd building-out capacitor; First building-out capacitor and the 3rd building-out capacitor are connected in series, and the non-series connection end of described first building-out capacitor is connected with the output of described LC filter unit, non-series connection end one end for being connected to described power transmit coils of described 3rd building-out capacitor; Being connected in series to hold of one end of described second building-out capacitor and described first building-out capacitor and the 3rd building-out capacitor is connected, and the other end of described second building-out capacitor is for being connected to the other end of described power transmit coils.First compensating unit adopts CCC type compensation topology structure, and can automatically regulate transmitting coil electric current according to the Mutual Inductance Coupling situation of transmitting-receiving power coil, mild through-put power is with the fluctuation of offset distance.

Further, the capacitance of described first building-out capacitor, the second building-out capacitor and the 3rd building-out capacitor is respectively C _cmi=1/ [| Z _cmi| × (2 π f ₀)]; Reactance value is respectively: $\left\{\begin{array}{c}{Z}_{cm1}=\[{\mathrm{\γ}}_1-(1+\mathrm{\β})\mathrm{\κ}\]Z_{L1}\\ Z_{cm2}=\frac{1}{\mathrm{\β}}{Z}_{cm1}\\ Z_{cm3}=(\mathrm{\κ}-1)Z_{L1}\end{array}\right.;$ Wherein, i is the sequence number of building-out capacitor, i=1,2,3; f ₀for system operating frequency; γ ₁be the first penalty coefficient, β is compensating proportion coefficient, and κ is the second penalty coefficient, Z _l1for the reactance of power transmit coils, Z _cm1be the reactance value of the first building-out capacitor, Z _cm2be the reactance value of the second building-out capacitor, Z _cm3it is the reactance value of the 3rd building-out capacitor.Compensating proportion factor beta, the first penalty coefficient γ ₁, the second penalty coefficient κ is defined as follows: $\left\{\begin{array}{c}\mathrm{\β}=Z_{cm1}/Z_{cm2}\\ {\mathrm{\γ}}_1=\[Z_{cm1}+Z_{L1}(1+\mathrm{\β})\]/Z_{L1}\\ \mathrm{\κ}=(Z_{L1}+Z_{cm3})/Z_{L1}\end{array}\right.;$ Compensating proportion factor beta represents the first compensating element, Z _cm1with the second compensating element, Z _cm2proportionality coefficient; First penalty coefficient γ ₁represent the power transfer characteristic of compensating network, determine the variation tendency of through-put power with the degree of coupling of power coil; Second penalty coefficient κ represents containing Z _l1the degree of compensation of branch road.

Further, described first building-out capacitor, the second building-out capacitor and the 3rd building-out capacitor are thin-film electro perhaps wattage ceramic electric capacity.

Further, described second compensating unit comprises the electric capacity C2 connected with described power receiving coil.

Further, the resonance frequency of the second compensating unit is equal with the reverse frequency of described high-frequency inversion unit.

Present invention also offers a kind of parameter acquiring method of the device for dynamic radio charging, comprise the steps:

(1) according to the excursion [k of coupling coefficient k _min, k _max] obtain coupling coefficient set point $k_{set}=\frac{1}{2}(k_{\min }+k_{max});$

(2) efficiency of transmission principle of optimality is utilized, and according to described coupling coefficient set point k _setobtain subcarrier band and carry Q _loadvalue and optimal load wherein Q _loadfor containing the quality factor of the secondary series loop of equivalent load; When coupling coefficient one timing, load determines efficiency of transmission, and selected optimal load ensure that system is with most high-transmission efficiency work.

(3) power fluctuation minimum principle is utilized, and according to described coupling coefficient set point k _setobtain compensating proportion factor beta and the first penalty coefficient γ ₁relation (1+ β)=γ ₁/ k _set; And obtain at described coupling coefficient set point k _setwith the through-put power under normal loading conditions when selected compensating parameter makes k change in setting range, the percentage of through-put power fluctuation is minimum.

(4) according to through-put power and at described coupling coefficient set point k _setupper known through-put power capacity P _tranobtain the first penalty coefficient and obtain compensating proportion factor beta=γ according to described first penalty coefficient ₁/ k _set-1;

(5) the second penalty coefficient κ is obtained according to the requirement of inverter bridge ZVS Sofe Switch;

(6) according to described first penalty coefficient γ ₁, described second penalty coefficient κ and described compensating proportion factor beta obtain reactance and the capacitance C of three building-out capacitors _cmi=1/ [| Z _cmi| × (2 π f ₀)]; $\left\{\begin{array}{c}{Z}_{cm1}=\[{\mathrm{\γ}}_1-(1+\mathrm{\β})\mathrm{\κ}\]Z_{L1}\\ Z_{cm2}=\frac{1}{\mathrm{\β}}{Z}_{cm1}\\ Z_{cm3}=(\mathrm{\κ}-1)Z_{L1}\end{array}\right.;$ Wherein, i is the sequence number of building-out capacitor, i=1,2,3; f ₀for system operating frequency; γ ₁be the first penalty coefficient, κ is the second penalty coefficient, β is compensating proportion coefficient, Z _l1for the reactance of power transmit coils, Z _cm1be the reactance value of the first building-out capacitor, Z _cm2be the reactance value of the second building-out capacitor, Z _cm3it is the reactance value of the 3rd building-out capacitor.

Further, in step (5), the step obtaining the second penalty coefficient κ is specially:

Obtain k=k _settime, input impedance Z _inphase angle with the change curve of described second penalty coefficient κ, and find on described curve and make Z _in(k _set) phase angle close to zero point, the κ value of this some correspondence is described second penalty coefficient κ;

Wherein, for the equivalent input impedance looked over to secondary from the output ab port of high-frequency inversion unit (12); Z _l1for the reactance of power transmit coils; Z _cm1it is the reactance value of the first building-out capacitor; Z _cm2it is the reactance value of the second building-out capacitor; κ is the second penalty coefficient, represents containing Z _l1the degree of compensation of branch road; Z _r=(ω M) ²/ Z ₂for secondary is mapped to the mapping impedance on former limit, represent that secondary is on the impact on former limit; Z ₂for containing the branch impedance of the secondary series loop of equivalent load.

Further, the resonance frequency of described second compensating unit (22) is equal with the reverse frequency of described high-frequency inversion unit (12); I.e. L ₂c ₂=1/ (2 π f ₀) ².

Further, the resonance frequency of LC filter unit (13) is equal with the reverse frequency of described high-frequency inversion unit (12); I.e. L _fc _f=1/ (2 π f ₀) ².

By the above technical scheme that the present invention conceives, compared with prior art, owing to considering efficiency of transmission, through-put power, the integration requirement of deviation range and the optimal design to compensating network parameter, the beneficial effect of stable transfer power and the anti-excursion capability of increase can be obtained.Under the constraint prerequisite of given power coil parameter, effectively deviation range and through-put power capacity requirement; can according to the automatic regulating power coil current of the Mutual Inductance Coupling degree of power coil according to the wireless charging device designed by the present invention; thus obtain the characteristic keeping stablizing power output; also there is high-transmission efficiency, Sofe Switch characteristic and unloaded current-limiting protection function simultaneously, be applicable to the wireless power transmission application scenario of wide deviation range.

Accompanying drawing explanation

Fig. 1 is the circuit topology of the embodiment of the present invention;

Fig. 2 is the WPT system simplified electrical circuit diagram based on mutual inductance coupling model;

Fig. 3 is at different penalty coefficient γ ₁lower power transmission factor g (γ ₁, x) with the change curve of independent variable x;

Fig. 4 is the parameter designing flow process of the compensation topology of the embodiment of the present invention;

Fig. 5 is the transmitting-receiving power coil structure chart of the embodiment of the present invention;

Fig. 6 is the input impedance phase angle changing trend diagram of the embodiment of the present invention, and wherein Fig. 6 (a) is at k=k _setpoint place, Z _inphase angle is with the change curve of the second penalty coefficient κ; Fig. 6 (b) is when κ=0.32, Z _inphase angle is with coupling coefficient k change curve

Fig. 7 is the output voltage V of the embodiment of the present invention _d2with the change curve of Mutual Inductance Coupling coefficient k with dispatch coil excursion percentage;

Fig. 8 is the change empirical curve of each branch current with dispatch coil excursion percentage of the embodiment of the present invention;

Fig. 9 is the change empirical curve of efficiency of transmission with dispatch coil excursion percentage of the embodiment of the present invention;

Figure 10 is the former limit inverter bridge output voltage V of the embodiment of the present invention _aband current i _cm1experimental waveform; Wherein, Figure 10 (a) is when dispatch coil is just to experimental waveform when namely excursion percentage is 0%; Figure 10 (b) is the experimental waveform of dispatch coil skew 40%.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

The object of the invention is the deficiency for the anti-excursion capability of existing compensation topology, a kind of device being applicable to the charging of wide skew dynamic radio is proposed, mainly comprise the compensation topology and parameter acquiring method thereof with anti-excursion capability, solve the through-put power easily problem of big ups and downs with offset distance change in existing wireless power transmission systems.

Device for dynamic radio charging provided by the invention comprises the energy transmitter module 1 being positioned over former limit and the energy acceptance module 2 being placed in secondary.Energy transmitter module 1 comprises high-frequency inversion unit 12, LC filter unit 13, first compensating unit 14, power transmit coils 15.Wherein the output a end of high-frequency inversion unit 12 is connected with one end of LC filter unit 13, the other end of LC filter unit 13 is connected to 01 end of the first compensating unit 14, the output b end of high-frequency inversion unit 12 is connected with 04 end of the first compensating unit 14, and 03 end of power transmit coils 15 and the first compensating unit 14 and 04 end are connected.High-frequency inversion unit 12 produces the high frequency voltage square wave V of excitation whole system _ab, its frequency is system operating frequency f ₀.The harmonic components of LC filter unit 13 filtering high frequency voltage square wave, harmonic reduction is on the impact of system.Be coupled by the high frequency magnetic field of power transmit coils 15 and power receiving coil 21, electric energy is from former limit wireless transmission to secondary.The function of the first compensating unit 14 automatically regulates transmitting coil electric current according to the Mutual Inductance Coupling situation of transmitting-receiving power coil, and mild through-put power is with the fluctuation of offset distance.When coupling distance increases, when Mutual Inductance Coupling coefficient k reduces, the first compensating unit 14 can increase according to mapping the variation tendency of impedance the electric current flowing to transmitting power coil automatically, thus avoids through-put power and increase with coupling distance and the problem that sharply declines.

Energy acceptance module 2 comprises power receiving coil 21, second compensating unit 22 and uncontrollable rectifier unit 23.Electric capacity C ₂be used for the leakage inductance of compensation power receiving coil 21.The output of the second compensating unit 22 is connected to c, d end of uncontrollable rectifier unit 23, and the output of uncontrollable rectifier unit 23 is connected to load.Second compensating unit 22 is full remuneration of substantially connecting, and makes only to transmit between power dispatch coil active power, thus improves system effectiveness.The high-frequency ac electric rectification of reception is direct current by uncontrollable rectifier unit 23, then supplies charging load.

The CCC type compensation topology being applicable to wide deviation range wireless power transmission that in the dynamic radio charging device proposed, the first compensating unit 14 adopts, is characterized in that:

(1) former limit inverter bridge adopts fixed mode frequently to work, and exports fixed frequency f at a, b end ₀alternating voltage square wave V _ab, inverter can be full-bridge or half-bridge, is become by set of power switches, such as power MOS pipe or IGBT, reverse frequency f ₀be selected between 20kHz-500kHz.

(2) first compensating units 14 are by three resonance compensation electric capacity C _cm1, C _cm2, C _cm3composition.Resonance compensation electric capacity can by excellent in high-frequency characteristics, and the thin-film capacitor connection in series-parallel that overcurrent capability is larger is formed, and also can adopt wattage ceramic electric capacity.No matter be that thin-film capacitor or wattage ceramic electric capacity all require to have high q-factor, high-frequency low-consumption feature.

(3) three resonance compensation electric capacity connected modes for going here and there and go here and there-T-shaped: the 3rd building-out capacitor C _cm3with former edge emitting coil L ₁a series arm in series, the second building-out capacitor C _cm2with by C _cm3, L ₁the branch circuit parallel connection of composition, its one end is connected to the 3rd building-out capacitor C _cm302 end, its other end is connected to former edge emitting coil L ₁04 end; First building-out capacitor C _cm1with by C _cm2, C _cm3, L ₁composition branch road series connection, its one end with by L _f, C _f01 end of the filter cell (13) that series connection is formed is connected, and the other end 02 is three compensation capacitance elements C _cm1, C _cm2, C _cm3common node.

(4) add by L between inverter bridge output a port and the first compensating unit 14 _f, C _fthe filter cell 13 that series connection is formed.L _fand C _fbe high q-factor reactance component, its reactance value should suitably be greater than power coil reactance value, and its series resonance frequency point is square-wave voltage V _abfrequency f ₀, namely meet C _fl _f=1/ (2 π f ₀) ², then the impedance of series filtering unit is approximately zero, does not change the power adjustments characteristic of the first compensating unit 14.Its function is the harmonic components of filtering high frequency voltage square wave, and harmonic reduction, on the impact of system, is avoided the building-out capacitor of the first compensating unit 14 to be directly connected to inverter bridge in addition and exported a, b end, cause switching tube to switch overshoot problem.

(5) one as circuit topology is out of shape, wherein filter capacitor C _fcan with the first building-out capacitor C _cm1merge into an electric capacity, its capacitance is two capacitances in series capacitance: C _f× C _cm1/ (C _f+ C _cm1).Containing the compensation topology of filter unit 13 and the first compensation topology unit 14 so actual is LCCC type.

The basic series connection compensation topology that in the dynamic radio charging device proposed, the second compensating unit 22 adopts, is characterized in that: the resonance frequency of the second compensating unit 22 arranges equal with the reverse frequency of high-frequency inversion unit 12, i.e. L ₂c ₂=1/ (2 π f ₀) ², be complete series compensation, make only to transmit active power between power dispatch coil, thus improve system effectiveness.

By three compensating element, C to the first compensating unit 14 _cm1, C _cm2, C _cm3the optimal design of parameter, described dynamic radio charging device can automatically regulate former limit power coil electric current according to the Mutual Inductance Coupling degree of transmitting-receiving power coil, thus obtains the characteristic keeping stablizing power output.The parameter acquiring method of the first compensating unit 14 of the present invention, its based on theoretical principle be summarized as follows:

Based on mutual inductance coupling model WPT system its simplify circuit as shown in Figure 2.Secondary maps impedance Z to the impact on former limit _rrepresent it, when Mutual Inductance Coupling coefficient k changes, its Z _rchange thereupon.Do not consider circuit parasitic loss ideally, map impedance Z _rthe active power obtained is the through-put power of system, also to represent in load obtain power.Suppose that the reactance of former and deputy limit power coil is expressed as Z respectively _l1=j ω L ₁, Z _l2=j ω L ₂, Z ₂=j ω L ₂+ 1/ (j ω C ₂)+R _acfor secondary circuit total impedance, then secondary is mapped to the equivalence mapping impedance on former limit is Z _r=(ω M) ²/ Z ₂, wherein for the mutual inductance value of former secondary power coil.DC load R _lequivalence to the equivalent AC load of the interchange cd port of uncontrollable rectifier unit (8) is then subcarrier band carries quality factor and is expressed as Q _load=| Z _l2|/R _ac.Three building-out capacitor reactance of former limit CCC type compensation topology are expressed as Z respectively _cm1=1/ (j ω C _cm1), Z _cm2=1/ (j ω C _cm2), Z _cm3=1/ (j ω C _cm3), three compensating element,s provide three and regulate the degree of freedom, define compensating proportion factor beta respectively, the first penalty coefficient γ ₁, the second penalty coefficient κ is as follows:

$\left\{\begin{array}{c}\mathrm{\β}=Z_{cm1}/Z_{cm2}\\ {\mathrm{\γ}}_1=\[Z_{cm1}+Z_{L1}(1+\mathrm{\β})\]/Z_{L1}\\ \mathrm{\κ}=(Z_{L1}+Z_{cm3})/Z_{L1}\end{array}\right.;$

Wherein compensating proportion factor beta represents the first compensating element, Z _cm1with the second compensating element, Z _cm2proportionality coefficient; First penalty coefficient γ ₁represent the power transfer characteristic of compensating network, determine the variation tendency of through-put power with the degree of coupling of power coil; Second penalty coefficient κ represents containing Z _l1the degree of compensation of branch road.

Definition independent variable x=|1+ β | k ²q _load, wherein k is the Mutual Inductance Coupling coefficient of transmitting-receiving power coil, Q _loadfor subcarrier band carries quality factor.Independent variable x contains Mutual Inductance Coupling coefficient k and load Q _loadchange mapping impedance Z _rimpact.Change due to transmission deviation distance shows as the fluctuation of Mutual Inductance Coupling coefficient k, therefore independent variable x is discussed on the impact of through-put power, can be used to set up the theoretical model that through-put power changes with offset distance.

Ignore the parasitic drain of circuit, by Circuit theory model, easily obtaining through-put power is

$\left\{\begin{array}{c}{P}_{tran}={\left|\frac{V_{ab}}{Z_{cm1}+(Z_{L1}+Z_r)(1+\mathrm{\β})}\right|}^2\mathrm{Re}\left(Z_r\right)=\frac{1}{\left|1+\mathrm{\β}\right|}\frac{{\left|V_{ab}\right|}^2}{\left|Z_{L1}\right|}g({\mathrm{\γ}}_1,x)\\ g({\mathrm{\γ}}_1,x)=1/(\frac{{{\mathrm{\γ}}_1}^2}{x}+x)\end{array}\right.$

Wherein g (γ ₁, x) be defined as power transmission factor, describe through-put power P _tranwith independent variable x=|1+ β | k ²q _loadconversion trend, Fig. 3 be setting different penalty coefficient γ ₁when transmission factor g (γ ₁, x) with the change curve of independent variable x.As can be seen from Figure 3, it is characterized by: g (γ ₁, x) at x _opt=γ ₁a bit there is maximum g in this _max=1/ (2 γ ₁), and it is comparatively smooth in the change of this vicinity, therefore namely method for designing of the present invention is this transmission feature that make use of former limit CCC type topology, the extreme point of the corresponding transmission factor of selected former limit CCC type topology near setting Mutual Inductance Coupling coefficient, thus keeps stable output when ensureing that through-put power changes in k value effective range.

The Parameters design of the CCC type compensation topology that its first compensating unit 14 adopts comprises following concrete steps, it is characterized in that:

(1) according to coupling coefficient k excursion [k _min, k _max], the selected coupling coefficient point k optimizing reference _set.

$k_{set}=\frac{1}{2}(k_{\min }+k_{max})$

(2) according to the design principle of efficiency of transmission optimum, setting optimal load R _lq is carried with corresponding subcarrier band _loadvalue.

$\left\{\begin{array}{c}{Q}_{load}^{opt}=1/k_{set}\\ R_L=\frac{R_{ac}}{{(2\sqrt{2}/\mathrm{\π})}^2}=\frac{1}{{(2\sqrt{2}/\mathrm{\π})}^2}\frac{\left|Z_{L2}\right|}{Q_{load}^{opt}}\end{array}\right.$

(3) according to power fluctuation minimum principle, setting compensation proportionality coefficient β and penalty coefficient γ ₁and the coupling coefficient point k of setting _setrelation.By transmission factor g (γ ₁, x) characteristic is known, and penalty coefficient is set as | γ ₁|=x (k _set) can ensure that through-put power is at k _setnear point, fluctuation is minimum, simultaneously at k _setpoint obtains maximum transmission power.Will with x=|1+ β | k ²q _loadbring equation into | γ ₁|=x (k _set) compensating proportion factor beta and penalty coefficient γ can be obtained ₁and the coupling coefficient point k of setting _setrelation:

$(1+\mathrm{\β})=\frac{{\mathrm{\γ}}_1}{k_{set}}$

Then at the coupling coefficient point k optimizing reference _seton, under normal loading conditions, through-put power is

$P_{tran}\left(k_{set}\right)=\frac{{\left|V_{in}\right|}^2}{\left|Z_{L1}\right|}\frac{k_{set}}{2{\left|{\mathrm{\γ}}_1\right|}^2}$

(4) basis is at k _setpoint transmits power capacity P _tranrequirement, the transmit power calculation formula provided by (3) step, can set the first penalty coefficient γ ₁

${\mathrm{\γ}}_1=\sqrt{k_{set}\frac{{\left|V_{in}\right|}^2/\left|Z_{L1}\right|}{2P_{tran}}}$

Compensating proportion factor beta=γ can be calculated thus ₁/ k _set-1.

(5) according to the requirement of inverter bridge ZVS Sofe Switch, the second penalty coefficient κ is set.At k=k _setpoint place, investigates Z _inphase angle with the variation tendency of the second penalty coefficient κ.Based on this, selected second penalty coefficient κ, makes to meet Sofe Switch requirement: when k is from k _setbe reduced to gradually in the process of 0, Z _inphase angle will increase to 90 ° of pure perception from micro-perception.The total input impedance Z looked over from former limit inverter bridge to side, pair side _infor

$Z_{in}=Z_{cm1}+\frac{Z_{cm2}({\mathrm{\κZ}}_{L1}+Z_r)}{(Z_{cm2}+{\mathrm{\κZ}}_{L1}+Z_r)}$

The parameter acquisition procedure of the second penalty coefficient κ is simply described below: when determining penalty coefficient γ according to preceding step ₁after β, be selected in k=k _setpoint place, makes input impedance Z _inphase angle with the second penalty coefficient κ change curve, on curve find make Z _in(k _set) phase angle close to zero namely in the point of faint perception, selected corresponding κ value.

(6) by the first penalty coefficient γ ₁, the second penalty coefficient κ and compensating proportion factor beta, calculate three compensating element, reactance needed for CCC type compensation topology and capacitance (C _cmi=1/ [| Z _cmi| × (2 π f ₀)], i=1,2,3).

$\left\{\begin{array}{c}{Z}_{cm1}=\[{\mathrm{\γ}}_1-(1+\mathrm{\β})\mathrm{\κ}\]Z_{L1}\\ Z_{cm2}=\frac{1}{\mathrm{\β}}{Z}_{cm1}\\ Z_{cm3}=(\mathrm{\κ}-1)Z_{L1}\end{array}\right.$

Under the constraint prerequisite of given power coil parameter, effectively deviation range and through-put power capacity requirement; can according to the automatic regulating power coil current of the Mutual Inductance Coupling degree of power coil according to the wireless charging device designed by the present invention; thus obtain the characteristic keeping stablizing power output; also there is high-transmission efficiency, Sofe Switch characteristic and unloaded current-limiting protection function simultaneously, be applicable to the wireless power transmission application scenario of wide deviation range.In embodiment part, in conjunction with specific embodiments, explanation will be further elaborated to the method for designing of the above working mechanism of the present invention, advantage and compensation topology parameter below.

Below in conjunction with accompanying drawing, its detailed embodiment is further illustrated to technical scheme of the present invention:

Proposed by the invention is applicable to wide deviation range dynamic radio charging device, and its system framework as shown in Figure 1.This system mainly comprises DC power supply 11, high-frequency inversion unit 12, former limit LC filter unit 13, first compensating unit 14, power transmit coils 15 and power receiving coil 21, second compensating unit 22, uncontrollable rectifier unit 23 and load 24.

Wherein, the effect of described DC power supply 11 is for high-frequency inversion unit 12 provides galvanic current to press V _d1; DC inverter is high frequency voltage square wave V by described high-frequency inversion unit 12 _ab, its structure is the full bridge inverter be made up of four switching tubes.Described former limit LC filter unit 13 is connected between inverter bridge output a and the first compensating unit 14, by filter inductance L _fwith filter capacitor C _fbe composed in series, its resonance frequency is former limit reverse frequency f ₀; Described first compensating unit 14 is by three building-out capacitor C _cm1, C _cm1and C _cm1connection in series-parallel forms.3rd building-out capacitor C _cm3with former edge emitting coil L ₁a series arm in series, the second building-out capacitor C _cm2with by C _cm3, L ₁the branch circuit parallel connection of composition, its one end is connected to the 3rd building-out capacitor C _cm302 end, its other end is connected to former edge emitting coil L ₁04 end; First building-out capacitor C _cm1with by C _cm2, C _cm3, L ₁composition branch road series connection, its one end with by L _f, C _f01 end of the filter cell 13 that series connection is formed is connected, and the other end 02 is three compensation capacitance elements C _cm1, C _cm2, C _cm3common node.Power transmit coils 15 is coupled by high frequency magnetic field with power receiving coil 21, and electric energy is delivered to secondary from former limit; Described second compensating unit 22 is tandem type full remuneration topology, by resonant capacitance C ₂be composed in series with power receiving coil 21, its resonance frequency and former limit reverse frequency f ₀identical; Its output c, d are connected with uncontrollable rectifier unit 23 input.Described uncontrollable rectifier unit 23 is by rectifier diode and filter capacitor C ₀form, the high-frequency alternating current of reception is transformed to direct current, supply load R _l.

Getting different first penalty coefficient γ ₁under, power transmission factor g (γ ₁, x) with independent variable x variation tendency as shown in Figure 3.G (γ ₁, variation tendency x) can be found out, when x is taken at extreme point x _opt=γ ₁near then transmission factor g (γ ₁, x) change is comparatively smooth, g (γ ₁, this characteristic x) is that mild through-put power provides possibility with offset distance fluctuation.In order to ensure that through-put power is steady within the scope of certain k, should set former limit penalty coefficient γ ₁, the independent variable x=|1+ β making k excursion corresponding | k ²q _loadat extreme point x _opt=γ ₁near.Described first compensating unit make use of its power transmission factor g (γ just ₁, this extreme point characteristic x), makes it automatically regulate transmitting coil electric current according to Mutual Inductance Coupling situation, mild through-put power fluctuation.

Fig. 5 gives a pair typical power dispatch coil 15,16 pictorial diagram.Receiving and dispatching power coil in figure is square coil, adopts litz wire to be embedded on poly (methyl methacrylate) plate.Power coil dimension reference actual electrical electrical automobile demand, be 1:5 scale model, because actual gap between ground and automobile is about 20cm, therefore in scale model, the down suction of dispatch coil remains 4cm.Definition laterally offset percentage δ is laterally offset amount Δ y and the ratio of transmitting coil lateral width.Because the variation relation of Mutual Inductance Coupling coefficient k with laterally offset percentage δ is not subject to contract than index impacts, therefore studies scale model and also can reflect actual shifts situation.Between dispatch coil Mutual Inductance Coupling coefficient k with laterally offset percentage δ variation tendency as shown in Figure 7.When laterally offset percentage has 0 to be increased to 45%, coupling coefficient k is reduced to 0.13 from 0.18.Power coil basic parameter and offset requirement as shown in table 1.

The basic parameter of table 1 power coil and requirement

Accompanying drawing 4 in conjunction with the embodiments illustrates that the parameter designing process of former limit CCC type compensation topology is as follows:

(1) according to coupling coefficient k excursion, the selected coupling coefficient point k optimizing reference _set=0.165.

(2) according to the design principle of efficiency of transmission optimum, setting subcarrier band carries Q _loadvalue and optimal load.Secondary Optimum Matching band carries quality factor equivalent AC load is $R_{ac}=\left|Z_{L_2}\right|/Q_{load}^{opt}=13.06\mathrm{\Ω};$ DC load is $R_L=R_{ac}/{(2\sqrt{2}/\mathrm{\π})}^2=16.13\mathrm{\Ω}.$ If actual loading is not optimal load, then in order to ensure that efficiency of transmission is optimum, generally add impedance matching circuit at secondary.Here suppose that nominal load is efficiency optimization value.

(3) according to through-put power capacity P _tran=500W requirement, sets the first penalty coefficient γ ₁

At k=k _setplace, maximum according to through-put power, through-put power fluctuation minimum principle, chooses the first penalty coefficient γ by through-put power capacity ₁.Then the first penalty coefficient γ ₁=0.2212, then proportionality coefficient β=γ ₁/ k _set-1=0.3407.Now the power characteristic of compensation topology is determined.

(4) according to the requirement of inverter bridge ZVS Sofe Switch, the second penalty coefficient κ is set

At k=k _setpoint place, investigates Z _inphase angle with the variation tendency of the second penalty coefficient κ.Wherein Z _infor the input impedance looked over to side, pair side from former limit inverter bridge.Fig. 6 (a) is at k=k _setpoint place, Z _inphase angle is with the change curve of the second penalty coefficient κ; Selected second penalty coefficient κ=0.32, makes Z _inat k=k _setpoint place is micro-perception.When selected second penalty coefficient, investigate Z further _inphase angle with the variation tendency of Mutual Inductance Coupling coefficient k, shown in Fig. 6 (b).When k is from k _setbe reduced in 0 process gradually, Z _inphase angle will increase to 90 ° of pure perception from micro-perception, meet Sofe Switch requirement.

(5) by the first penalty coefficient γ ₁, the second penalty coefficient κ and compensating proportion factor beta, calculate three compensating element, reactance needed for the CCC type compensation topology of former limit and capacitance.

Therefore penalty coefficient and compensating element, thereof are chosen as:

$\left\{\begin{array}{c}{k}_{set}=0.165\\ {\mathrm{\γ}}_1=0.2212\\ \mathrm{\κ}=0.32\end{array}\right.\⇒\left\{\begin{array}{c}{C}_{cm1}=35.024nF\\ C_{cm2}=11.933nF\\ C_{cm3}=10.704nF\end{array}\right.$

According to design parameter above, built CCC former limit compensation topology respectively, the experimental result for CCC type former limit compensation topology is as follows.

Fig. 7 is output voltage V _d2with laterally offset percentage δ variation tendency, theoretical have necessarily little deviation with experiment value, but trend is consistent.This deviation is owing to not considering the voltage utilization that inverter bridge dead band is caused, and also has the loss in side circuit and tube voltage drop.Can illustrate from the contrast figure, the theoretical model provided above can reflect the power transfer characteristic of compensation topology well.Within the scope of 0-40% excursion percentage, output voltage does not obviously reduce, and the compensation topology parameter obtained according to method for designing proposed by the invention can meet the anti-offset requirement of setting.

Fig. 8 be each branch current with laterally offset percentage δ variation tendency, along with departing from of receiving coil, former limit branch current I _l1can increase gradually, and secondary current I _l2can reduce.This curent change trend is just reflecting the Power auto-adjustment ability of former limit CCC type compensation topology.When offset distance increases, Mutual Inductance Coupling coefficient k reduces, and secondary is mapped to the mapping impedance Z on former limit _rreduce, therefore need to increase primary current I _l1, to keep constant through-put power.When Mutual Inductance Coupling coefficient k is reduced to zero, when namely receiving coil leaves transmitting coil completely, former limit branch current I _l1increase to certain value, there will not be obvious overshooting problem, therefore have unloaded current limiting capacity, this is necessary for dynamic radio charging very much.

Fig. 9 be from former limit DC source to secondary DC output end efficiency of transmission with the variation tendency of laterally offset percentage δ, in the deviation range of 40%, all can keep greater efficiency more than 90%.

Figure 10 is inverter bridge output voltage V _aband current i _cm1experimental waveform contrast.When coil just pair time, as shown in Figure 10 (a), inverter bridge output current lags behind output voltage square wave a little, and switching time electric current is less, and lagging phase angle is micro-perceptual state close to zero.When being displaced to maximum effective percentage 40%, lagging phase angle is increased to about 45 °, as shown in Figure 10 (b).From k _maxto in 0 change procedure, inverter bridge is in Sofe Switch state all the time, consistent with theory analysis.Therefore the dynamic radio charging device of proposed by the invention and design is under transmission range situation of change, can ensure that through-put power is stable and export, and being applicable to very much transmission range has certain deviation scope and through-put power to have the wireless charging occasion of certain stability requirement.

It should be noted that the above power coil parameter is the citing of embodiment, the present invention is not limited only to this kind of power coil.The above is only the preferred embodiments of the invention, under the premise without departing from the principles of the invention, can also make further improvement, and these improvement also should be considered as protection scope of the present invention.

Those skilled in the art will readily understand; the foregoing is only preferred embodiment of the present invention; not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1., for a device for dynamic radio charging, it is characterized in that, comprise energy transmitter module (1) and energy acceptance module (2); Described energy transmitter module (1) comprises the high-frequency inversion unit (12), LC filter unit (13), the first compensating unit (14) and the power transmit coils (15) that connect successively;

Described high-frequency inversion unit (12) carries out inversion process and output high voltage square wave V for the direct voltage inputted outside _ab, described LC filter unit (13) is for high frequency voltage square wave V described in filtering _abin harmonic components, described power transmit coils (15) is launched for the mode be coupled according to high frequency magnetic field by the high frequency voltage square wave after after filtering; Described first compensating unit (14), for regulating the electric current of described power transmit coils (15), reduces the fluctuation of through-put power with offset distance;

Described energy acceptance module (2) comprises the power receiving coil (21), the second compensating unit (22) and the uncontrollable rectifier unit (23) that connect successively;

The power that described power receiving coil (21) is launched for receiving described power transmit coils (15); Described second compensating unit (22), for compensating the leakage inductance of described power receiving coil (21), makes only to transmit active power between described power transmit coils (15) and described power receiving coil (21); Described uncontrollable rectifier unit (23) is for being direct current by the high-frequency ac electric rectification of reception, and supply load.

2. device as claimed in claim 1, it is characterized in that, described first compensating unit (14) comprises the first building-out capacitor _,second building-out capacitor and the 3rd building-out capacitor;

Described first building-out capacitor and the 3rd building-out capacitor are connected in series, the non-series connection end of described first building-out capacitor is connected with the output of described LC filter unit (13), and the non-series connection end of described 3rd building-out capacitor is used for the one end being connected to described power transmit coils (15);

Being connected in series to hold of one end of described second building-out capacitor and described first building-out capacitor and the 3rd building-out capacitor is connected, and the other end of described second building-out capacitor is used for the other end being connected to described power transmit coils (15).

3. device as claimed in claim 2, it is characterized in that, the capacitance of described first building-out capacitor, the second building-out capacitor and the 3rd building-out capacitor is respectively C _cmi=1/ [| Z _cmi| × (2 π f ₀)]; Reactance value is respectively: $\left\{\begin{array}{c}{Z}_{cm1}=\[{\mathrm{\γ}}_1-(1+\mathrm{\β})\mathrm{\κ}\]Z_{L1}\\ Z_{cm2}=\frac{1}{\mathrm{\β}}{Z}_{cm1}\\ Z_{cm3}=(\mathrm{\κ}-1)Z_{L1}\end{array}\right.;$ Wherein, i is the sequence number of building-out capacitor, i=1,2,3; f ₀for system operating frequency; γ ₁be the first penalty coefficient, κ is the second penalty coefficient, β is compensating proportion coefficient, Z _l1for the reactance of power transmit coils, Z _cm1be the reactance value of the first building-out capacitor, Z _cm2be the reactance value of the second building-out capacitor, Z _cm3it is the reactance value of the 3rd building-out capacitor.

4. the device as described in any one of claim 1-3, is characterized in that, described first building-out capacitor, the second building-out capacitor and the 3rd building-out capacitor are thin-film electro perhaps wattage ceramic electric capacity.

5. device as claimed in claim 1, it is characterized in that, described second compensating unit (22) comprises the electric capacity C2 connected with described power receiving coil.

6. device as claimed in claim 5, it is characterized in that, the resonance frequency of described second compensating unit (22) is equal with the reverse frequency of described high-frequency inversion unit (12).

7., for a parameter acquiring method for the device of dynamic radio charging, it is characterized in that, comprise the steps:

(1) according to the excursion [k of coupling coefficient k _min, k _max] obtain coupling coefficient set point $k_{set}=\frac{1}{2}(k_{min}+k_{max});$

(2) efficiency of transmission principle of optimality is utilized, and according to described coupling coefficient set point k _setobtain subcarrier band and carry Q _loadvalue $Q_{load}^{opt}=1/k_{set}$ And optimal load $R_L=\frac{1}{{(2\sqrt{2}/\mathrm{\π})}^2}\frac{\left|Z_{L2}\right|}{Q_{load}^{opt}};$

(3) power fluctuation minimum principle is utilized, and according to described coupling coefficient set point k _setobtain compensating proportion factor beta and the first penalty coefficient γ ₁relation and obtain at described coupling coefficient set point k _setwith the through-put power under normal loading conditions

(4) according to through-put power and at described coupling coefficient set point k _setupper known through-put power capacity P _tranobtain the first penalty coefficient and obtain compensating proportion factor beta=γ according to described first penalty coefficient ₁/ k _set-1;

(5) the second penalty coefficient κ is obtained according to the requirement of inverter bridge ZVS Sofe Switch;

(6) according to described first penalty coefficient γ ₁, described second penalty coefficient κ and described compensating proportion factor beta obtain reactance and the capacitance C of three building-out capacitors _cmi=1/ [| Z _cmi| × (2 π f ₀)]; $\left\{\begin{array}{c}{Z}_{cm1}=\[{\mathrm{\γ}}_1-(1+\mathrm{\β})\mathrm{\κ}\]Z_{L1}\\ Z_{cm2}=\frac{1}{\mathrm{\β}}{Z}_{cm1}\\ Z_{cm3}=(\mathrm{\κ}-1)Z_{L1}\end{array}\right.;$ Wherein, i is the sequence number of building-out capacitor, i=1,2,3; f ₀for system operating frequency; Z _l1for the reactance of power transmit coils; Z _cm1it is the reactance value of the first building-out capacitor; Z _cm2it is the reactance value of the second building-out capacitor; Z _cm3it is the reactance value of the 3rd building-out capacitor.

8. parameter acquiring method as claimed in claim 7, it is characterized in that, in step (5), the step obtaining the second penalty coefficient κ is specially:

Obtain k=k _settime, input impedance Z _inphase angle with the change curve of described second penalty coefficient κ, and find on described curve and make Z _in(k _set) phase angle close to zero point, the κ value of this some correspondence is described second penalty coefficient κ;

Wherein, z _l1for the reactance of power transmit coils; Z _cm1it is the reactance value of the first building-out capacitor; Z _cm2it is the reactance value of the second building-out capacitor; κ is the second penalty coefficient, represents containing Z _l1the degree of compensation of branch road; Z _r=(ω M) ²/ Z ₂for secondary is mapped to the mapping impedance on former limit, represent that secondary is on the impact on former limit; Z ₂for containing the branch impedance of the secondary series loop of equivalent load.

9. parameter acquiring method as claimed in claim 7 or 8, it is characterized in that, the resonance frequency of described second compensating unit (22) is equal with the reverse frequency of described high-frequency inversion unit (12).

10. parameter acquiring method as claimed in claim 7 or 8, it is characterized in that, the resonance frequency of described LC filter unit (13) is equal with the reverse frequency of described high-frequency inversion unit (12).