Summary of the invention
The application is a kind of based on T- Π composite resonant network ECPT system and its Parameters design by providing, to solve
In the prior art in order to obtain the circuit system problem that structure is complicated, at high cost caused by constant voltage output characteristic, and transmitting
End resonance circuit cannot work causes the soft hand-over frequency of the power factor reduction of system and inverter to float in ZPA state
The technical issues of shifting.
In order to solve the above technical problems, the application is achieved using following technical scheme:
One kind being based on T- Π composite resonant network ECPT system, including DC power supply, high-frequency inverter circuit, T-LCL resonance
Network, by compensation inductance LsAnd two pairs of coupling plates constitute coupling unit, Π-CLC resonant network, current rectifying and wave filtering circuit with
And load RL, wherein the DC power supply is changed into alternating voltage, the T-LCL Resonance Neural Network via the high-frequency inverter circuit
Network is by resonant inductance L1t, resonant inductance L2tAnd resonant capacitance CtIt constitutes, the resonant inductance L1tOne end and resonance electricity
Feel L2tOne end connection, the resonant inductance L1tThe other end connect the first output end of the high-frequency inverter circuit, it is described humorous
Shake inductance L2tThe other end and the compensation inductance LsOne end connection, the resonant capacitance CtOne end be connected to the resonance
Inductance L1tWith resonant inductance L2tBetween, the resonant capacitance CtThe other end connect one piece of transmitting pole plate and the high-frequency inversion
The second output terminal of circuit, the compensation inductance LsThe other end connect another piece of transmitting pole plate, the Π-CLC resonant network
By resonant inductance Lp, resonant capacitance C1pAnd resonant capacitance C2pIt constitutes, in the resonant capacitance C1pBoth ends be respectively connected with one
Block receives pole plate, and transmitting pole plate couples realization energy wireless transmission, resonant capacitance C with pole plate one-to-one correspondence is received1pOne end warp
Cross resonant inductance LpIt is connect with the first input end of the current rectifying and wave filtering circuit, resonant capacitance C1pThe other end and the rectification filter
Second input terminal of wave circuit connects, between the first input end and the second input terminal of the current rectifying and wave filtering circuit described in connection
Resonant capacitance C2p, the load R is connected between two output ends of the current rectifying and wave filtering circuitL。
Further, the resonant capacitance C1pCapacitance and the resonant capacitance C2pCapacitance it is equal.
A kind of Parameters design based on T- Π composite resonant network ECPT system, includes the following steps:
S1: the working frequency f of the system and equivalent capacity C of coupling unit is determined according to the demand of application scenarioss, into
And calculate compensation inductance Ls;
S2: fixed load resistance value R is givenL, output voltage UoutAnd equivalent load changes percentage α, wherein equivalent load variation
Percentage α includes the increased percentage α of equivalent load resistance value+The percentage α reduced with equivalent load resistance value-;
S3: judge whether to meetIf it is, S5 is entered step, otherwise,
Enter step S4, wherein thd2For the total harmonic distortion rate setting value of Π-CLC resonant network, η0For coupling unit efficiency of transmission
Setting value, RsFor the equivalent resistance of coupling unit dielectric lossWith compensation inductance equal series resistanceThe sum of, ReIt is whole
Flow filter circuit and load RLEquivalent load resistance value;
S4: reduce | α-|, and the S3 that gos to step;
S5:The quality factor q of selection Π-CLC resonant network in rangeπ;
S6: the resonant inductance L of Π-CLC resonant network is acquiredp, resonant capacitance C1pAnd resonant capacitance C2p;
S7: judge whether to meetIf it is, entering step S9, otherwise, S8 is entered step,
Wherein, thd1For the total harmonic distortion rate setting value of T-LCL resonant network;
S8: reduce | α+|, and the S3 that gos to step;
S9:The quality factor q of interior selection T-LCL resonant networkt;
S10: resonant inductance L is acquired according to the characteristic of T-LCL resonant network1t, resonant inductance L2tAnd resonant capacitance Ct;
S11: determine that DC input voitage is according to the characteristic of Fourier transformation and system
Further, thd1=10%, thd2=10%, η0=90%.
Further, in step S2, equivalent load changes percentageIn formula, Re' it is ReEquivalent load resistance value after variation.
Further, in step S6, the resonant inductance L of Π-CLC resonant network is acquired according to following relationshipp, resonance electricity
Hold C1pAnd resonant capacitance C2p:
Qπ=ω0C2pRπ;
λπ=C1p/C2p=1;
In formula,For resonant inductance LpReactance,For resonant capacitance C1pReactance, ω0For natural resonance angular frequency
Rate, RπFor the equivalent resistance of Π-CLC resonant network.
Compared with prior art, technical solution provided by the present application, the technical effect or advantage having are: realizing when negative
When load resistance value changes in a certain range, output voltage is held essentially constant, while guaranteeing that system operates in ZPA state, is not necessarily to
It is additional to increase communication and adjusting control circuit, effectively reduce the cost and complexity of system.
Embodiment
One kind be based on T- Π composite resonant network ECPT system, as shown in Figure 1, include DC power supply, high-frequency inverter circuit,
T-LCL resonant network, by compensation inductance LsAnd coupling unit, Π-CLC resonant network, rectification that two pairs of coupling plates are constituted
Filter circuit and load RL, wherein the DC power supply is changed into alternating voltage, the T- via the high-frequency inverter circuit
LCL resonant network is by resonant inductance L1t, resonant inductance L2tAnd resonant capacitance CtIt constitutes, the resonant inductance L1tOne end with
The resonant inductance L2tOne end connection, the resonant inductance L1tThe other end connect the first defeated of the high-frequency inverter circuit
Outlet, the resonant inductance L2tThe other end and the compensation inductance LsOne end connection, the resonant capacitance CtOne end connect
It connects in the resonant inductance L1tWith resonant inductance L2tBetween, the resonant capacitance CtThe other end connect one piece of transmitting pole plate and
The second output terminal of the high-frequency inverter circuit, the compensation inductance LsThe other end connect another piece of transmitting pole plate, the Π-
CLC resonant network is by resonant inductance Lp, resonant capacitance C1pAnd resonant capacitance C2pIt constitutes, in the resonant capacitance C1pBoth ends
It is respectively connected with one piece of reception pole plate, transmitting pole plate couples realization energy wireless transmission, resonance electricity with pole plate one-to-one correspondence is received
Hold C1pOne end pass through resonant inductance LpIt is connect with the first input end of the current rectifying and wave filtering circuit, resonant capacitance C1pThe other end
It is connect with the second input terminal of the current rectifying and wave filtering circuit, in the first input end and the second input terminal of the current rectifying and wave filtering circuit
Between connect the resonant capacitance C2p, the load R is connected between two output ends of the current rectifying and wave filtering circuitL。
The working principle of system are as follows: DC power supply is changed into alternating voltage via high-frequency inverter circuit, humorous by T-LCL afterwards
Vibrating network provides constant stimulus current for coupling unit, when two pieces of reception pole plates are placed near transmitting pole plate, alternating electric field
Potential difference is generated on receiving pole plate, using rectifying and wave-filtering after Π-CLC resonant network at constant voltage needed for load.
Fig. 2 is the equivalent circuit of coupling unit and receiving unit, UdFor the driving voltage of coupling unit, CsFor coupling unit
Equivalent capacity, and Cs=Cs1Cs2/(Cs1+Cs2),For the equivalent resistance of coupling unit dielectric loss,To compensate inductance
LsEqual series resistance, R2For the equivalent inpnt resistance value of receiving unit.Mainly with the insulating materials coated on pole plate and
Medium between pole plate is related, and meetsIn formula, γ is Dielectric loss tangent value.Coupling unit it is equivalent
Series resistance isWithThe sum of, and use RsIt indicates.
For the ECPT system under high frequency state that works, RsIt can reach more than ten ohm.In order to improve the transmission effect of system
Rate, it is necessary to R2Significantly larger than Rs, however the equivalent load resistance value of existing ECPT system is usually in the range of (10 Ω, 100 Ω)
It is interior, if coupling unit, directly to this load transmission energy, the efficiency of system is lower.Therefore the present invention coupling unit with it is whole
It is provided with Π-CLC resonant network between stream filter circuit to realize the high input resistance value of receiving unit, while guaranteeing output voltage
Not with load RLVariation and change.
Π-CLC resonant network under pressure constant state needs constant sinusoidal current source as input, on the other hand, higher
In the case where output power, the driving voltage of coupling unit is usually higher and the pressure voltage of often higher than most of MOSFET.
However by the characteristic of MOSFET it is found that its optimal operational condition is low-voltage and high-current.Therefore humorous in order to both be able to satisfy Π-CLC
The input demand of vibrating network, while solving both coupling unit high pressure activation demand and inverter switching device pipe subnormal voltage operation demand
Between contradiction, the present invention between high-frequency inverter circuit and coupling unit be provided with T-LCL resonant network.
The effect of T-LCL resonant network is to provide constant current drive for coupling unit and rise driving voltage again, and Π-CLC is humorous
Vibrating network is to realize constant voltage output and high-efficiency transfer.
Fig. 3 is the topology of Π-CLC resonant network, wherein ReFor current rectifying and wave filtering circuit and load RLEquivalent load resistance value,
And Re=π2RL/8.According to the relationship between branch reactance, Π-CLC resonant network has three parameter configuration methods:
In formula,Respectively resonant inductance Lp, resonant capacitance C1pAnd resonant capacitance C2pElectricity
It is anti-.In topology, Π-CLC resonant network is about resonant inductance LpSymmetrically, because the network that the method one and method three are configured has
There is similitude, thus following only analysis method one and 2 two kinds of situations of method.
Method one:
In this manner when Configuration network, the input impedance of network is
In formula, ω0For natural resonance angular frequency, ωnFor normalized radian frequency, QπFor quality factor, λπFor the ratio between capacitor,
And meet
ωn=ω/ω0 (5)
Qπ=ω0C2pRe (6)
λπ=C1p/C2p (7)
The output voltage phasor of Π-CLC resonant network is
The output voltage of Π-CLC resonant network is relative to the gain of input voltage
When Π-CLC resonant network work in resonance frequency, i.e. ωn=1, in conjunction with (3) (8) (9) Shi Ke get
And work as λπ=1, that is, C1pWith C2pWhen capacitance is equal,
Gv=Qπ (14)
It can see by formula (13) (15), when Π-CLC resonant network is in resonant state and equal capacitance, network
Output voltageWith ReUnrelated, the input impedance of network is in purely resistive, and its resistance value is load equivalent resistance value
Times.
Method two:
Under the relationship of the branch impedance, the input impedance of network is
Wherein
WhenWhen, it can get using identical analysis method
And work as λπWhen=1,
Contrast (13) (15) (18) are it can be found that in identical QπUnder conditions of, the Π-CLC configured using method two is humorous
Vibrating network ratio method one has higher output voltage and input impedance.
Fig. 4 is the topology of T-LCL resonant network, wherein Uinv0For the fundamental component of inverter output voltage, RtIt is single for coupling
The equivalent resistance of member and its receiving unit, and meet Rt=Rs+Zp_in, it is assumed herein that compensation inductance LsC is fully compensateds.In the same manner,
According to the relationship of branch reactance, T-LCL network also has there are three types of configuration method
Using identical analysis method, the transmission characteristic of T-LCL resonant network under available three kinds of configuration methods, and with
The characteristic of Π-CLC resonant network is same to be listed in table 1, wherein Qt=ω0L2t/Rt.As can be seen that two kinds of resonant networks are in transmission characteristic
It is upper that there is symmetry, except that T-LCL resonant network may be implemented constant current output under resonance condition, and Π-CLC
Resonant network then exports constant voltage.In identical RtAnd QtUnder conditions of, the T-LCL resonant network ratio that is configured using method two
Method one has higher output electric current It.Therefore compared to method one, the T-LCL resonant network that uses method two to design can be with
Higher driving voltage is provided for coupling unit.
The transmission characteristic of table 1 Π-CLC and T-LCL resonant network
According to above-mentioned analysis it is found that under resonance condition, when loading resistance value and changing, Π-CLC resonant network can be with
Maintain output voltage constant, while T-LCL resonant network provides constant current excitation for coupling unit and guarantees system work always
Make in ZPA state.Therefore, the present invention, which is not only not necessarily to complicated closed control circuit, can be realized constant voltage output, but also system
Power factor and Sofe Switch frequency not will receive the influence of load resistance value.
Below by the total harmonic distortion rate THD of overall analysis system, frequency sensitivity and the variable range of load, and herein
On the basis of provide the design method of system major parameter.
(1) total harmonic distortion rate THD
It is the key that guarantee system normal operation and preferable Electro Magnetic Compatibility that system, which has preferable harmonic inhibition capability,
Factor.THD characterizes circuit to the rejection ability of higher hamonic wave.Smaller THD shows circuit to the inhibiting effect of higher hamonic wave
It is stronger.Main harmonic source is the rectifier bridge in the inverter and receiving unit in transmitting unit in ECPT system.
As filter inductance LfWith filter capacitor CfWhen sufficiently large, load current IoIn ripple can ignore, thus rectifier bridge
Input current IrecIt can be considered ideal square wave electric current.When T-LCL resonant network and Π-CLC resonant network are all made of respective match
When setting the design of method one, according to the general definition of percent harmonic distortion, the full harmonic wave that can acquire rectifier bridge input voltage by Fig. 1 is abnormal
Variability are as follows:
In formula, the order of m expression higher hamonic wave, N=2k+1, k=1,2,3..., and when N is sufficiently large, formula can be acquired
20 are
In the same manner, inverter output current I can be obtainedinvTotal harmonic distortion rate be
When N is sufficiently large, THD can be obtained1=0.134Qt (23)
For using resonant network designed by other three kinds of configuration methods, corresponding percent harmonic distortion is listed in table 2, in table
Tx-ΠxIndex number ' x ' represent use configuration method, such as T2-Π1Indicate T-LCL resonant network and Π-CLC Resonance Neural Network
Method two is respectively adopted in network and parameter is arranged in method one.THD in across comparison table as it can be seen that same configuration T-LCL resonance
Under network, the configuration method of Π-CLC resonant network does not interfere with THD1, in the same manner, the configuration method of T-LCL resonant network
It will not influence THD2.This is because the compensation inductance L of coupling unitsIt is inhibited to higher hamonic wave, so that transmitting
Unit and receiving unit in harmonic wave will not influence each other;The THD under different configuration methods is further compared, it can be seen that T2-
Π1Under THD1And THD2The analog value of other configurations method will be lower than.Therefore according to table 2, in order to ensure in system
Harmonic wave is sufficiently small, Ying Caiyong T2-Π1Configuration method carrys out the parameter of designing system.In addition, in order to ensure aberration rate is in some restriction
It is worth the quality factor q hereinafter, T-LCL resonant networktWith upper limit value Qt_up, the quality factor q of Π-CLC resonant networkπThen have
There is lower limit value Qπ_low。
The THD value of 2 system of table
(2) frequency sensitivity
In systems in practice, inevitably there is deviation in the parameter of resonant network and its calculated value, so that network
Working frequency off-resonance frequency, therefore, for the steady operation of system, the impedance operator of resonant network to the variation of frequency not
It can be too sensitive.
For the Π-CLC resonant network configured using method one, Π-CLC resonant network can be obtained according to formula (3)
Input impedance angle about ωnWith QπCircle of equal altitudes, as shown in Figure 5.By formula 20,21 it is found that in order to enable THD2It is sufficiently small,
QπValue want as big as possible.However, from figure 5 it can be seen that excessive QπThe input impedance angle pair of Π-CLC resonant network will be will cause
The variation of frequency is too sensitive, thus QπIt can not be excessively high.Here, Q is chosen in compromiseπ_up=3, such as figure orbicular spot position.
In addition, being by the efficiency of transmission that Fig. 2 can acquire coupling unit with formula 15
It can be seen that QπIt is excessively high while to will lead to η too low.Thus QπUpper limit value need by Π-CLC resonant network frequency sensitive
Property and the efficiency of transmission of coupling unit determine jointly, use Q hereinπ_upTo indicate.In actual design, QπIt needs
(Qπ_low,Qπ_up) choosing value is carried out in section.
Use the input impedance angle of the available T-LCL resonant network configured in method two of identical method about ωnWith Qt
Circle of equal altitudes, such as Fig. 6.As seen from Figure 6, too small QtThe impedance angle of T-LCL resonant network will be caused to the variation of frequency
In sensitivity, this illustrates QtWith lower limit value Qt_low, compromise is chosen for Q hereint_low=0.5, as shown in Fig. 6 orbicular spot.In reality
In the design of border, QtIt needs in (Qt_low,Qt_up) choosing value is carried out in section.
(3) variable range is loaded
By the analysis of front it is found that the output voltage of Π network will not change with the variation of load resistance value, but T-LCL
The quality factor of resonant network and Π-CLC resonant network can then change correspondingly.Since the quality factor of two kinds of networks exist pair
The variable section answered, then there is also corresponding variable ranges for load.
The variation percentage of equivalent load resistance value is expressed as
In formula, R 'eEquivalent load resistance value after indicating load variation, α+And α-Respectively indicate equivalent load resistance value increase and
Reduced percentage.So load change after corresponding Π-CLC resonant network and T-LCL resonant network quality factor and
Coupling unit efficiency of transmission is respectively
Q′π=Qπ(1+α) (26)
Q′t=Qt(1+α) (27)
Through analytical formula 27,28 and table 2 it is found that when equivalent load resistance value increases, THD1It will will increase, simultaneous transmission
Efficiency can also decline.In order to guarantee the total harmonic distortion rate of T-LCL resonant network lower than setting value thd1And efficiency of transmission is high
In setting value η0, α+It needs to meet
The case where reducing for load, by formula 26 and table 2 it is found that THD2It will increase therewith.In order to ensure Π-CLC
The total harmonic distortion rate of resonant network is lower than setting value thd2, α-Then to meet
To sum up formula 29,30, the range for loading the variation percentage of resistance value are
Assuming that thd1And thd2It is no more than 10%, the efficiency of transmission of coupling unit is not less than 90%, then load resistance value can
Variation range is
According to the requirement of the THD of system, frequency sensitivity and load three aspects of variable range, being presented below ensures
THD1< 10%, THD2The System Parameter Design method of < 10% and η > 90%.
A kind of Parameters design based on T- Π composite resonant network ECPT system, as shown in fig. 7, comprises following step
It is rapid:
S1: the working frequency f of the system and equivalent capacity C of coupling unit is determined according to the demand of application scenarioss, into
And calculate compensation inductance Ls;
S2: fixed load resistance value R is givenL, output voltage UoutAnd equivalent load changes percentage α, wherein equivalent load variation
Percentage α includes the increased percentage α of equivalent load resistance value+The percentage α reduced with equivalent load resistance value-;
In formula, Re' it is ReEquivalent load resistance value after variation;
S3: judge whether to meetIf it is, S5 is entered step, otherwise,
Enter step S4, wherein thd2For the total harmonic distortion rate setting value of Π-CLC resonant network, η0For coupling unit efficiency of transmission
Setting value, RsFor the equivalent resistance of coupling unit dielectric lossWith compensation inductance equal series resistanceThe sum of, ReIt is whole
Flow filter circuit and load RLEquivalent load resistance value;
S4: reduce | α-|, and the S3 that gos to step;
S5:The quality factor q of selection Π-CLC resonant network in rangeπ;
S6: the resonant inductance L of Π-CLC resonant network is acquiredp, resonant capacitance C1pAnd resonant capacitance C2p;
The resonant inductance L of Π-CLC resonant network is acquired according to following relationshipp, resonant capacitance C1pAnd resonant capacitance
C2p:
Qπ=ω0C2pRπ;
λπ=C1p/C2p=1;
In formula,For resonant inductance LpReactance,For resonant capacitance C1pReactance, ω0For natural resonance angular frequency
Rate, RπFor the equivalent resistance of Π-CLC resonant network;
S7: judge whether to meetIf it is, entering step S9, otherwise, S8 is entered step,
Wherein, thd1For the total harmonic distortion rate setting value of T-LCL resonant network;
S8: reduce | α+|, and the S3 that gos to step;
S9:The quality factor q of interior selection T-LCL resonant networkt;
S10: resonant inductance L is acquired according to the characteristic of T-LCL resonant network1t, resonant inductance L2tAnd resonant capacitance Ct;
S11: determine that DC input voitage is according to the characteristic of Fourier transformation and system
Finally, in order to verify the correctness of the constant-voltage characteristic of proposed system and Parameters design, with working frequency
500KHz, output loading 100 Ω, output voltage 100V, equivalent binding capacitance 350pF, thd1=10%, thd2=10%, η0=
For 90%, according to above-mentioned parameter design cycle, the major parameter of system is obtained, and establishes and emulates according to Fig. 1 in MATLAB
Model.For the ease of comparing emulation with experiment as a result, the value of element is all made of the measured value of experimental provision in simulation model
Such as table 3.
3 system major parameter of table
The simulation waveform of the output voltage of system such as Fig. 8, the output voltage steady-state value loaded within the period 1 are 98.5V;?
t1Moment, load are decreased to 90 Ω, and output voltage reaches steady-state value 98.2V again after about 0.57ms;In t2Moment is born
Load increases to 110 Ω, and output voltage is stabilized to 98.5V again after 0.79ms.It can be seen that when load is with itself resistance value
10% when being reduced or increased, and the steady-state value of output voltage can maintain essentially in 98.5V.In the t of load jump1And t2It is moment, defeated
There is 6% or so variation in voltage out, this is because the exciting current of coupling unit needs several periods just after load sudden change
It can reach again stable.On the whole, output voltage is basically stable at 98.5V.There are 1.5% with theoretical value 100V for the value
Deviation, this mainly as caused by the higher hamonic wave of inverter and rectifier bridge.
In the steady-state operation of period 1, the output voltage U of inverterinvWith electric current IinvSimulation waveform such as Fig. 9.Inversion
The THD of electric current1It is 5.7%.And the inverter current THD of period 2 and period 31It is then respectively 5.2% and 5.7%, and according to formula
The THD of 22 three periods calculated1It is divided into 5.76%, 5.1% and 6.3%, emulates almost the same with calculated result.Rectifier bridge
Input voltage UrecWith electric current IrecSimulation waveform such as Figure 10, UrecTHD2It is 8.7%, is kissed with the calculated value 8.8% of formula 20
It closes.The THD of period 2 and period 32Respectively 9.6% and 8.7%, respectively less than 10%.
The experimental provision built.Coupling unit is by the identical 20cm × 20cm metal being printed on pcb board of four block sizes
Copper foil composition.Transmitting and the spacing received between pole plate are 3mm.The MOSFET pipe of full-bridge inverter uses ST Microelectronics
STP20NM30.In order to reduce the high-frequency loss in experimental provision, capacitor used is the produced cat's silver electricity of CDE company
Hold, inductance core is the high frequency magnetic core of MICROMETALS, and rectifier bridge is made of MUR1520G Ultrafast recovery diode.
Figure 11 (a) is the experimental waveform of output voltage when load resistance value increases to 110 Ω from 100 Ω.It can be seen that negative
At the time of carrying switching, there is the variation of 10V or so in output voltage, rear recovery to 100V or so.Figure 11 (b) be load resistance value from
100 Ω are decreased to the wave mode of output voltage when 90 Ω, it can be seen that the variation of load does not interfere with output voltage substantially.Inversion
The output voltage U of deviceinvWith electric current Iinv, rectifier bridge input voltage UrecWith electric current IrecSuch as Figure 11 (c), it can be seen that experiment wave
Shape and the simulation waveform in Fig. 9 and Figure 10 are almost the same.Designed model machine can export 100W with 83% overall efficiency
Power, the efficiency of transmission of coupling unit is higher than 90%.
It is a kind of based on T- Π composite resonant network ECPT system and its parameter by providing in above-described embodiment of the application
Design method is arranged T-LCL resonant network in transmitting unit and provides constant current drive for coupling unit, is arranged in receiving unit
Π-CLC resonant network realizes constant voltage output, in analysis total harmonic distortion rate, frequency sensitivity and load variable range
On the basis of give System Parameter Design method, the invention realize when load resistance value change in a certain range when, output electricity
Pressure is held essentially constant, while guaranteeing that system operates in ZPA state, increases communication and adjusting control circuit without additional, effectively
Reduce the cost and complexity of system.
It should be pointed out that the above description is not a limitation of the present invention, the present invention is also not limited to the example above,
Variation, modification, addition or the replacement that those skilled in the art are made within the essential scope of the present invention, are also answered
It belongs to the scope of protection of the present invention.