CN109617250B - Anti-deviation wireless power transmission system based on combined topology - Google Patents

Abstract

The invention discloses an anti-offset wireless power transmission system based on a combined topology, which is suitable for wireless power transmission occasions, wherein the voltage provided to a load under a larger offset is approximately constant, and the fluctuation is smaller. The system comprises a high-frequency full-bridge inverter circuit, a primary side compensation network, a loose coupling transformer, a secondary side compensation network and a full-bridge rectification filter circuit. The combined topology utilizes the output characteristics of S/LCC and LCC/S compensation topologies, realizes the supply of approximately constant voltage to a load under the condition that a coil has larger offset by connecting a primary side in series and a secondary side in parallel, can realize the approximately zero power factor of input impedance and the soft switching of a switching device, solves the problem that the output voltage of the existing constant voltage output wireless power transmission system fluctuates greatly along with the offset of a coil of a loose coupling transformer, and can integrate the design of the loose coupling transformer adopted in the two topologies without increasing extra volume.

Description

Anti-deviation wireless power transmission system based on combined topology

Technical Field

The invention discloses an anti-deviation wireless power transmission system based on a combined topology, and belongs to the wireless power transmission technology.

Background

The Wireless Power Transfer (WPT) technology is convenient to use, safe and reliable because there is no electrical and mechanical connection between the Power supply end and the Power receiving end. Currently, an electromagnetic induction type wireless Power Transfer (IPT) technology is the most widely applied WPT technology, and therefore, the WPT technology has great research value.

The loose coupling transformer adopted by the IPT technology has low coupling coefficient and large leakage inductance value, and reactive loop current is inevitably generated in a circuit, so that the stress and the loss of a device are increased, and therefore, a compensation network is generally adopted to compensate reactive energy generated by leakage inductance. Also, the compensation network can achieve constant current or constant voltage output required over a wide load range and guarantee a Zero input Phase Angle (ZPA). According to the connection mode of the compensation capacitor, the compensation network has four basic topologies: SS (series-series), SP (series-parallel), PS (parallel-series), PP (parallel-parallel), wherein, SS topology and PP topology can respectively realize constant current output irrelevant to load under specific operating frequency, and simultaneously guarantee input ZPA. In a similar way, the SP topology and the PS topology can respectively realize constant voltage output irrelevant to load under specific working frequency, and simultaneously ensure input of ZPA. However, the outputs of the four basic topologies are all limited by transformer parameters, and the degree of freedom in designing the transformer parameters is reduced. In order to solve the above problems, the LCC/S, S/LCC and the bilateral LCC have been proposed to improve the degree of freedom of the transformer parameter design.

Because the IPT adopts the loosely coupled transformer to transmit energy, and the transmitting coil and the receiving coil can move freely, the situation that the two coils shift inevitably occurs in the actual charging process, which causes parameter change of the compensation network and larger fluctuation of output voltage or current. New control strategies have been developed to address the transformer coil offset problem, but with reduced transmission efficiency and reliability. Some coil design methods have been proposed, for example: DD. Coil structures such as DDQ, however, do not effectively improve the offset problem. In the prior art, the characteristics of an S/LCC compensation topology and an LCC/S compensation topology are utilized, constant voltage output and ZPA are realized in a mode of connecting a primary side in parallel and a secondary side in series, and meanwhile, the characteristics have good offset resistance.

From the above analysis, it can be known that, in the present combined topology which can realize constant voltage output and input of ZPA and has good offset resistance, the problem that the voltage and current stresses of the combined topology increase exponentially after the deviation of the transformer coil increases beyond a certain range still exists.

Disclosure of Invention

The invention aims to provide an anti-offset wireless power transmission system based on a combined topology aiming at the defects of the prior art, which utilizes the characteristics of an S/LCC compensation topology and an LCC/S compensation topology, realizes the constant voltage output and input of ZPA and anti-offset capability through the connection mode of the primary side in series connection and the secondary side in parallel connection, and solves the problems of overvoltage and overcurrent of the existing constant voltage output combined topology.

The invention adopts the following technical scheme for realizing the aim of the invention:

an anti-offset wireless power transmission system based on a combined topology comprises a high-frequency full-bridge inverter circuit, a primary side compensation network, a loose coupling transformer, a secondary side compensation network and a full-bridge rectification filter circuit which are sequentially connected. Wherein, former limit compensating network includes: first former limit compensating capacitor, second former limit compensating capacitor, former limit compensating inductance and former limit additional capacitance, the compensation network of secondary includes: first secondary limit compensation electric capacity, second secondary limit compensation electric capacity, secondary limit compensation inductance, secondary limit additional capacitance, the loose coupling transformer includes: a first loosely coupled transformer and a second loosely coupled transformer.

One pole of the first primary side compensation capacitor is connected with the middle point of one bridge arm of the high-frequency full-bridge inverter circuit, the other pole of the first primary side compensation capacitor is connected with one end of the primary side winding of the first loose coupling transformer, one end of the primary side compensation inductor is connected with the other end of the primary side winding of the first loose coupling transformer, the other end of the primary side compensation inductor and one pole of the second primary side compensation capacitor are both connected with one pole of the primary side additional capacitor, the other pole of the primary side additional capacitor is connected with one end of the primary side winding of the second loose coupling transformer, and the other pole of the second primary side compensation capacitor and the other end of the primary side winding of the second loose coupling transformer are both connected with the middle point of the other bridge arm of the high-frequency full-bridge inverter circuit. One pole of the secondary side additional capacitor is connected with one end of a secondary side winding of the first loose coupling transformer, the other pole of the secondary side additional capacitor and one pole of the first secondary side compensation capacitor are connected with one end of a secondary side compensation inductor, one pole of the second secondary side compensation capacitor is connected with one end of a secondary side winding of the second loose coupling transformer, the other end of the secondary side compensation inductor and the other pole of the second secondary side compensation capacitor are connected with a middle point of one bridge arm of the full bridge rectification filter circuit, and the other pole of the first secondary side compensation capacitor, the other end of the secondary side winding of the first loose coupling transformer and the other end of the secondary side winding of the second loose coupling transformer are connected with the middle point of the other bridge arm of the full bridge rectification filter circuit.

In order to reduce the volume of the loose coupling transformer, the design of the integrated coil coupling transformer is adopted, two groups of coils share one group of magnetic core structure, and the characteristics are as follows: mutual inductance between transformer coils except M₁₂And M₃₄Other cross-coupling mutual inductances can be ignored, and two groups of coil mutual inductances M under different offsets₁₂And M₃₄Can be obtained by experimental tests, and the two mutual inductances satisfy a linear relationship: m₁₂＝aM₃₄+ b. Above, M₁₂Is the mutual inductance between primary and secondary windings of the first loosely coupled transformer, M₃₄Is the mutual inductance between the primary and secondary windings of the second loosely coupled transformer, and a and b are the secondAnd fitting equation coefficients of the mutual inductance of the first-loose coupling transformer coil and the second-loose coupling transformer coil are obtained by fitting experimental data.

From the above, the voltage gain and coil mutual inductance M of the system₁₂And M₃₄The relationship of (1) is:

G_VVas a function of mutual inductance. Setting the mutual inductance of the primary and secondary coils of the first loose coupling transformer and the second loose coupling transformer as M respectively when the primary and secondary coils are opposite to each other without deviation_{12_coax}And M_{34_coax}At the time of voltage gain of

The mutual inductance when the primary and secondary coils of the first loose coupling transformer and the second loose coupling transformer deflect maximally is respectively M_{12_align}And M_{34_align}When the allowable fluctuation range of the voltage gain is + -x (percentage), the voltage gain is

The above two formulas can be combined to obtain the primary and secondary compensation inductance value L in the allowable voltage gain fluctuation range_f1And L_f2。

Has found L_f1And L_f2From the above voltage gain function

It can be seen that as the transformer coil mutual inductance decreases, i.e. from just no offset to the occurrence of the maximum offset, the voltage gain G_VVShows the variation trend of increasing first and then decreasing when the mutual inductance is changed

When the temperature of the water is higher than the set temperature,

G_VVoccurrence of maximum value, M_{34_inflec}The value of the coil mutual inductance corresponding to the maximum value of the voltage gain. Examination M_{34_coax}And M_{34_align}And M_{34_inflec}Relationship if M_{34_inflec}<M_{34_align}<M_{34_coax}Or M_{34_align}<M_{34_coax}<M_{34_inflec}L as determined above_f1And L_f2And the constraint condition requirements are met. If M is_{34_align}<M_{34_inflec}<M_{34_coax}Voltage gain at M_{34_inflec}Time is maximum, and voltage gain fluctuation x (percentage) occurs at M_{34_inflec}Thus, L as claimed above_f1And L_f2The relation of constraint condition requirements is no longer satisfied, and the two relations need to be connected again

And

III, solving M again_{34_inflec}、L_f1And L_f2Size. Wherein, V_INInputting a DC voltage, V, to the system_OIs the output voltage.

Capacitance value C of first primary side compensation capacitor₁Capacitance value C of the second primary side compensation capacitor_PThe capacitance value C of the first secondary compensation capacitor_SAnd the second auxiliary edge compensating capacitor capacitance value C₄According to the following

And

selecting capacitance value C of primary side additional capacitor₃Capacitance value C of secondary side additional capacitor₂According to

And

and (4) selecting. Where ω is the angular frequency of system operation, L₁Is a firstInductance of the primary side self-inductance of a loosely coupled transformer, L₂Is the inductance, L, of the secondary side self-inductance of the first loosely coupled transformer₃Is the inductance, L, of the primary side self-inductance of the second loosely coupled transformer₄Is the inductance of the secondary side self-inductance of the second loosely coupled transformer.

The first primary side compensation capacitor C of the combined topology primary side compensation network₁And primary side compensation inductance L_f1The device can be equivalent to a device under the angular frequency omega of the system operation, the number of topological devices is further reduced, and the circuit is simplified.

When the system works in a constant voltage output mode, the input impedance Z_INComprises the following steps:

is purely resistive and outputs a voltage V_OComprises the following steps:

and the output voltage is approximately constant under the larger offset, and the fluctuation is smaller. Wherein, R is load equivalent resistance. Meanwhile, the switching between the constant voltage mode and the constant current mode can be realized by adding an additional auxiliary circuit and a control method, and the determination method of the compensation parameter is the same.

By adopting the technical scheme, the invention has the following beneficial effects:

(1) the invention provides an anti-offset wireless power transmission system based on a combined topology, which can realize constant voltage output under specific frequency, and simultaneously realize approximately constant output voltage and small fluctuation under larger offset by utilizing the circuit characteristics of the combined topology.

(2) The anti-migration wireless power transmission system based on the combined topology provided by the invention has the advantages that the voltage and current stress of the combined topology cannot exceed the bearing range of system devices along with the continuous increase of the deviation of the primary coil and the secondary coil of the loose coupling transformer, the problems of overvoltage and overcurrent of the anti-migration combined topology for realizing constant voltage output are solved, and the stability of the system is improved.

(3) In the whole charging process, the input impedance of the system is approximate to pure resistance, reactive circulation is avoided, the stress of the device is reduced, meanwhile, the soft switching of the switching device is realized, and the efficiency is improved.

Drawings

Fig. 1 is a topology structural diagram of an anti-migration radio power transmission system based on a combined topology.

Fig. 2(a) and 2(b) are respectively the equivalent circuit of the integrated transformer coil structure and the variation curve of the mutual inductance of the transformer coil with the coil offset.

FIG. 3 is a combined topology voltage gain G_VVFollowing mutual inductance M of coil₃₄A curve of variation.

FIG. 4 is a graph showing the v of the combined topology in the constant voltage output mode when the equivalent resistance of the battery is 50 Ω_gate、v_AB、i_ABAnd V_OAnd (4) waveform diagrams.

FIG. 5 shows the v of the combined topology operating in the constant voltage output mode with the equivalent resistance of the battery at 100 Ω_gate、v_AB、i_ABAnd V_OAnd (4) waveform diagrams.

FIG. 6 shows the v of the combined topology operating in the constant voltage output mode when the equivalent resistance of the battery is 150 Ω_gate、v_AB、i_ABAnd V_OAnd (4) waveform diagrams.

FIG. 7 shows a second loosely coupled transformer coil mutual inductance M for the combined topology operating in the constant voltage output mode₃₄V at 40 μ, 30 μ and 20 μ, respectively_OAnd (4) waveform diagrams.

FIG. 8 is a graph of current stress with coil mutual inductance M for a combined topology operating in a constant voltage output mode₃₄Decreasing but changing graph.

FIG. 9 shows voltage stress following coil mutual inductance M for the combined topology operating in constant voltage output mode₃₄Decreasing but changing graph.

The reference numbers in the figures illustrate: 1 is a high-frequency full-bridge inverter circuit, 2 is a primary side compensation network, 3 is a loose coupling transformer unit, 4 is a secondary side compensation network, 5 is a full-bridge rectifier filter circuit, 6 is a load, and Q is₁、Q₂、Q₃、Q₄Is a first, a second, a third and a fourth power tube L₁Is the primary side self-inductance of the first loosely coupled transformer,L₂for the secondary side self-inductance, L, of the first loosely coupled transformer₃Is the primary side self-inductance, L, of the second loosely coupled transformer₄For secondary side self-inductance, L, of the second loosely coupled transformer_f1Compensating the inductance for the primary side, L_f2Compensating the inductance for the secondary side, C_PCompensating the capacitance for the second primary side, C_SCompensating the first side for capacitance, C₁Compensating the capacitance for the first primary side, C₂Adding a capacitor, C, to the secondary side₃Adding a capacitor to the primary side, C₄Compensating the second secondary side for capacitance, D₁、D₂、D₃、D₄Is a first, a second, a third and a fourth diode, C_fTo output the filter capacitance.

Detailed Description

The technical scheme of the invention is explained in detail in the following with reference to the attached drawings.

In order to solve the overvoltage and overcurrent problems of the existing offset-resistant combined topology with constant voltage output, a primary side series compensation network and a secondary side parallel compensation network are constructed on the primary side and the secondary side of a loosely coupled transformer comprising two groups of coils, the trend that the voltage gain is increased and then decreased along with the decrease of the mutual inductance of the transformer coils is presented according to the relation between the mutual inductance of the two groups of coils and the voltage gain, the parameter value of the primary side compensation inductance and the secondary side compensation inductance is determined within the allowable voltage gain fluctuation range, the parameter values of other compensation elements are determined according to the circuit characteristics of the combined topology, and the output voltage is approximately constant under large offset while constant voltage output under specific frequency is realized by utilizing the characteristics of the S/LCC compensation topology and the LCC/S compensation topology.

The invention discloses an anti-deviation wireless power transmission system based on a combined topology, which is shown in figure 1 and comprises: the high-frequency full-bridge inverter circuit comprises a high-frequency full-bridge inverter circuit 1, a primary side compensation network 2, a loose coupling transformer unit 3 comprising a first loose coupling transformer and a second loose coupling transformer, a secondary side compensation network 4 and a full-bridge rectification filter circuit 5.

The high-frequency full-bridge inverter circuit 1 comprises a first power tube Q₁And a third power tube Q₃A bridge arm and a second power tube Q₂And a fourth power tube Q₄Another bridge arm of the combinationFirst power tube Q₁And a third power tube Q₃The connecting point of the first power tube Q is the middle point A of the bridge arm₂And a fourth power tube Q₄The connecting point of (a) is the bridge arm midpoint B.

The primary compensation network 2 includes: first primary side compensation capacitor C₁A second primary side compensation capacitor C_PPrimary side compensation inductance L_f1And an additional primary capacitor C₃First primary side compensation capacitor C₁Is connected with the middle point of one bridge arm of the high-frequency full-bridge inverter circuit 1, and a first primary side compensation capacitor C₁Is connected with one end of the primary winding of the first loosely coupled transformer, and the primary side compensation inductance L_f1Is connected with the other end of the primary winding of the first loosely coupled transformer, and a primary compensation inductance L_f1Another end of the first primary side compensating capacitor C_POne pole of the primary side and the primary side additional capacitor C₃Is connected with the primary side additional capacitor C₃Is connected to one end of the primary winding of a second loosely coupled transformer, a second primary compensation capacitor C_PThe other pole of the first loosely coupled transformer and the other end of the primary winding of the second loosely coupled transformer are both connected with the middle point of the other bridge arm of the high-frequency full-bridge inverter circuit 1.

The secondary side compensation network 4 includes: first secondary compensation capacitor C_SAnd a second auxiliary compensation capacitor C₄Secondary side compensation inductance L_f2Secondary side additional capacitance C₂Secondary side additional capacitance C₂Is connected with one end of the secondary winding of the first loose coupling transformer, and the secondary side is added with a capacitor C₂The other electrode of the first auxiliary side compensation capacitor C_SCompensation inductance L of one pole and secondary side_f2Is connected to the second secondary side compensation capacitor C₄One pole of the first secondary side compensation inductor is connected with one end of a secondary side winding of the second loose coupling transformer, and the secondary side compensation inductor L_f2The other end and the second auxiliary side of the capacitor C₄The other pole of the first secondary side compensation capacitor C is connected with the middle point of one bridge arm of the full-bridge rectification filter circuit 5_SThe other pole of the second transformer, the other end of the secondary winding of the first loose coupling transformer and the other end of the secondary winding of the second loose coupling transformer are connected with the middle point of the other bridge arm of the full bridge rectification filter circuit 5.

The full-bridge rectifying and filtering circuit 6 comprises a first diode D₁A third diode D₃A bridge arm and a second diode D₂A fourth diode D₄Another bridge arm formed by the output filter capacitor C_fConnected in parallel with the output end of the full-bridge rectification filter circuit 5, and the load 6 is connected in parallel with the output filter capacitor C_fBetween the two poles.

The anti-offset wireless power transmission system based on the combined topology shown in fig. 1 outputs a constant voltage and an input impedance Z during normal operation_INComprises the following steps:

is purely resistive and outputs a voltage V_OComprises the following steps:

and the output voltage is approximately constant under the larger offset, and the fluctuation is smaller.

Fig. 2(a) is an equivalent circuit of an integrated transformer coil structure, and fig. 2(b) is a variation curve of transformer coil mutual inductance with coil offset. As can be seen from FIG. 2(b), the mutual inductance between the transformer coils divides M₁₂And M₃₄Other cross-coupling mutual inductances are negligible, so that the circuit analysis only considers the coil mutual inductance M₁₂And M₃₄。

FIG. 3 is a combined topology voltage gain G_VVFollowing mutual inductance M of coil₃₄A curve of variation. As can be seen, when the coil is mutually induced M₃₄Voltage gain G when varied over an offset range_VVFluctuation is small, and voltage gain G_VVFollowing coil mutual inductance M₃₄The decrease of (c) shows a trend of increasing first and then decreasing when the mutual inductance M of the coil₃₄Reducing voltage gain G outside of offset range_VVIs exponentially decreased, wherein M_{34_coax}The corresponding mutual inductance value of the transformer coil without deviation, M_{34_align}For the coil mutual inductance value, M, corresponding to the maximum deflection of the transformer coil_{34_inflec}The value of the coil mutual inductance corresponding to the maximum value of the voltage gain.

Fig. 4 to 9 are combined typeBy taking the topology as an example, the effectiveness of the anti-offset wireless power transmission system based on the combined topology is verified. The first loosely coupled transformer has coupling coefficient k of 0.176 and primary self-inductance L₁232.5uH, secondary self-induction L₂232.6 uH; the second loosely coupled transformer has a coupling coefficient k of 0.18 and a primary side self-inductance L₃246.4uH, minor edge self-induction L₄At 246.5uH, the system input voltage V_INAt 220V, duty D is 1, constant voltage charging voltage is 220V, and coefficients a and b of the fitted equation of transformer coil mutual inductance are 1.265 and-13.1, respectively. Setting the switching frequency to 85kHz, and compensating inductance L of primary and secondary sides_f1And L_f218.48uH and 72.77uH, primary side and secondary side compensation capacitors C₁、C_PAnd C₄、C_S15.1nF, 189.7nF, 14.2nF and 48.2nF respectively, and primary and secondary side additional capacitances C₃And C₂15.4nF and 21.94nF, respectively.

Fig. 4 to 6 show the driving signals v when the combined topology operates in the constant voltage output mode and the battery equivalent impedances are 50 Ω, 100 Ω and 150 Ω, respectively_gateCombined topology input voltage v_ABInput current i_ABAnd outputting a charging voltage V_OThe simulated waveform of (2). It can be seen from the figure that when the equivalent resistance of the battery is changed from 50 Ω to 150 Ω, the output voltage is substantially maintained at 220V, which is not changed with the load. Combined topology input current i_ABAnd an input voltage v_ABThe phase is basically the same, reactive energy is effectively reduced, input current slightly lags behind bridge arm voltage, zero-voltage switching of the MOSFET switching tube is facilitated, and switching loss is reduced.

FIG. 7 shows the mutual inductance M of the coil when the combined topology is operated in the constant voltage output mode and the load equivalent resistance is 100 Ω₃₄V at 40 μ, 30 μ and 20 μ respectively_OAnd (5) simulating a waveform diagram. When the coil is mutual inductance M₃₄At 40 mu, the output voltage V_O220V; when coil mutual inductance M₃₄When the output voltage is 30 mu, the output voltage V is_O232V; when coil mutual inductance M₃₄When 20 mu, the output voltage V_OThe output voltage fluctuation is in the range of 5% at 215V, verifying that the proposed combination topology has good offset resistance.

FIGS. 8-9 show combined topology current and voltage stress as a function of coil mutual inductance M operating in a constant voltage output mode₃₄Decreasing but changing graph. As can be seen, the mutual inductance M of the coil is followed₃₄Reduced, combined topology current-divided transformer primary side self-inductance L₃The current stress of (A) increases and the growth trend is reduced, and other currents all show a reduction trend, and similarly, the capacitor C_P、C₃The voltage stress is increased, the growth trend is reduced, the voltage stress of other capacitors is reduced, and the voltage stress and the current stress are in the bearing range of the device, so that the stability of the system is improved.

Claims (4)

1. An anti-migration wireless power transmission system based on a combined topology, comprising: a high-frequency full-bridge inverter circuit, a primary side compensation network, a loose coupling transformer unit comprising a first loose coupling transformer and a second loose coupling transformer, a secondary side compensation network, a full-bridge rectification filter circuit,

the primary side compensation network comprises: a first primary side compensation capacitor, a second primary side compensation capacitor, a primary side compensation inductor and a primary side additional capacitor, wherein one pole of the first primary side compensation capacitor is connected with the midpoint of one bridge arm of the high-frequency full-bridge inverter circuit, the other pole of the first primary side compensation capacitor is connected with one end of the primary side winding of the first loose coupling transformer, one end of the primary side compensation inductor is connected with the other end of the primary side winding of the first loose coupling transformer, the other end of the primary side compensation inductor and one pole of the second primary side compensation capacitor are both connected with one pole of the primary side additional capacitor, the other pole of the primary side additional capacitor is connected with one end of the primary side winding of the second loose coupling transformer, the other pole of the second primary side compensation capacitor and the other end of the primary side winding of the second loose coupling transformer are both connected with the midpoint of the other bridge arm of the high-frequency full-bridge inverter circuit,

the secondary side compensation network comprises: the secondary side compensation circuit comprises a first secondary side compensation capacitor, a second secondary side compensation capacitor, a secondary side compensation inductor and a secondary side additional capacitor, wherein one pole of the secondary side additional capacitor is connected with one end of a secondary side winding of a first loose coupling transformer, the other pole of the secondary side additional capacitor and one pole of the first secondary side compensation capacitor are connected with one end of a secondary side compensation inductor, one pole of the second secondary side compensation capacitor is connected with one end of a secondary side winding of a second loose coupling transformer, the other end of the secondary side compensation inductor and the other pole of the second secondary side compensation capacitor are connected with a middle point of one bridge arm of the full bridge rectification filter circuit, and the other pole of the first secondary side compensation capacitor, the other end of the secondary side winding of the first loose coupling transformer and the other end of the secondary side winding of the second loose coupling transformer are connected with the middle point of the other bridge arm of the full bridge rectification filter circuit;

in the range of the allowable fluctuation of the voltage gain, determining the parameter value of a primary side compensation inductor and the parameter value of a secondary side compensation inductor according to the relation between the mutual inductance of a primary side coil and a secondary side coil of the loose coupling transformer and the voltage gain, and determining the parameter values of other compensation elements according to the circuit characteristics of the combined topology;

the method comprises the following steps of determining a parameter value of a primary side compensation inductor and a parameter value of a secondary side compensation inductor according to the relationship between the mutual inductance of a primary side coil and a secondary side coil of a loose coupling transformer and the voltage gain within the range of voltage gain allowed to fluctuate according to the following method:

the loose coupling transformer unit is realized by an integrated coil coupling transformer, a first loose coupling transformer and a second loose coupling transformer share a group of magnetic core structures, and the mutual inductance M of a primary coil and a secondary coil of the first loose coupling transformer₁₂Mutual inductance M of primary and secondary side coils of second loose coupling transformer₃₄The linear relationship is satisfied: m₁₂＝aM₃₄+ b, a and b are linear coefficients, and the mutual inductance value M of the first loose coupling transformer and the second loose coupling transformer when the primary and secondary coils are opposite to each other and have no deviation is obtained through experimental tests_{12_coax}、M_{34_coax}And the mutual inductance value M when the primary coil and the secondary coil of the first loose coupling transformer and the second loose coupling transformer deviate to the maximum_{12_align}、M_{34_align}；

The mutual inductance corresponding voltage gain expression when the primary and secondary side coils of the simultaneous loose coupling transformer are just opposite to each other without deviation:

corresponding to mutual inductance when primary and secondary windings of loosely-coupled transformer have maximum excursionThe voltage gain expression:

determining the inductance value L of a primary compensation inductance_f1And the inductance L of the secondary compensation inductor_f2Determining a mutual inductance value M of primary and secondary windings of a second loosely coupled transformer corresponding to the maximum voltage gain according to the determined primary compensation inductance and secondary compensation inductance_{34_inflec}，

X is the range of allowable fluctuation of voltage gain, V_IN、V_OThe input voltage and the output voltage of the wireless power transmission system;

satisfies M_{34_inflec}<M_{34_align}<M_{34_coax}Or M_{34_align}<M_{34_coax}<M_{34_inflec}Primary side compensation inductance of_f1And the inductance L of the secondary compensation inductor_f2Compensating the optimal solution of the inductance parameter for the primary and secondary side, M_{34_align}<M_{34_inflec}<M_{34_coax}And updating a mutual inductance value M of the primary and secondary side coils of a second loose coupling transformer corresponding to the maximum voltage gain_{34_inflec}Inductance value L of primary side compensation inductor_f1Secondary side compensation inductance value L_f2。

2. The combined topology based anti-migration radio power transmission system according to claim 1, wherein the parameter values of the other compensation elements are determined according to the circuit characteristics of the combined topology according to the following expression,

C₁compensating the capacitance, C, of the capacitor for the first primary side_PCompensating the capacitance, C, of the capacitor for the second primary side_SCompensating the capacitance, C, of the capacitor for the first side₄Compensating the capacitance, C, of the capacitor for the second minor edge₃Capacitance value, C, of an additional capacitor on the primary side₂The capacitance value of the secondary side additional capacitance, omega is the angular frequency of the system operation, L₁Is the inductance, L, of the primary side self-inductance of the first loosely coupled transformer₂Is the inductance, L, of the secondary side self-inductance of the first loosely coupled transformer₃Is the inductance, L, of the primary side self-inductance of the second loosely coupled transformer₄Is the inductance of the secondary side self-inductance of the second loosely coupled transformer.

3. The anti-migration wireless power transmission system based on the combined topology of claim 2, wherein the first primary side compensation capacitor and the primary side compensation inductor are equivalent to one device at an angular frequency of system operation.

4. The system of claim 2, wherein the wireless power transmission system is further characterized in that,

when the system works in a constant voltage output mode, the input impedance Z_INComprises the following steps:

is purely resistive and outputs a voltage V_OComprises the following steps:

and R is load equivalent resistance.

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