Compensation network and compensation method for arbitrary constant voltage wireless power transmission based on relay coil

Abstract

The present invention relates to an arbitrary constant voltage wireless power transmission compensation network and compensation method based on a relay coil. The arbitrary constant voltage wireless power transmission compensation network containing a relay coil includes a transmitting coil loop, a relay coil loop, and a receiving coil loop. The transmitting coil loop includes a voltage source, a transmitting coil, and a transmitting coil loop compensation capacitor connected in series. The relay coil loop includes a relay coil connected in series, a relay coil loop compensation capacitor, and the receiving coil loop includes a receiving coil, a receiving coil loop series compensation capacitor, a receiving coil loop parallel compensation capacitor, and a load. The present invention adds a parallel compensation capacitor on the basis of maintaining the original compensation network structure, and through the design of compensation parameters, the system obtains constant voltage output characteristics of different levels and effectively reduces the capacity of the inverter. Compared with the traditional three-coil structure, it is less likely to have detuning problems.

Description

Technical Field

[0001] The invention relates to a compensation network and a compensation method for wireless power transmission based on arbitrary constant voltage of a relay coil. Background Art

[0002] With the rapid development of the electric vehicle industry, people have put forward higher requirements for the safety and convenience of charging systems. Therefore, contactless charging systems for electric vehicles have also been more and more widely used. When the transmission distance increases, the transmission efficiency of the wireless power transmission system decreases rapidly. To solve this problem, inserting a relay coil between the transmitting coil and the receiving coil is a simple, easy, economical and effective way to increase the distance of wireless energy transmission.

[0003] The existence of the relay coil plays the role of an energy transfer station, but the system has multiple power transmission paths, which makes the system's compensation network design complex and difficult to obtain good output characteristics.

[0004] At present, the existing compensation method is to control the self-inductance of each coil to be consistent with the resonant frequency of the compensation capacitor to improve the energy transmission capacity of the system. However, in this compensation method, first, the output characteristics of the load are determined by the entire magnetic coupling system, and the internal reactance of the system cannot be fully compensated, and the output voltage regulation characteristics are poor. Second, the magnetic coupling system containing a relay coil in the application has three resonant frequencies, which is more likely to cause the detuning problem of the compensation network than the two-coil system without a relay coil. Third, the magnetic coupling system containing a relay coil has a cross-coupling problem. The prior art eliminates the influence of the cross-coupling effect by adding an impedance matching network or a series reactance compensation method on the basis of each coil resonant compensation network. However, such a compensation method requires an increase in the number of devices, and once the magnetic coupling system is given, its output characteristics are completely determined, and different output characteristics cannot be obtained by designing the compensation network parameters. The present invention aims at the cross-coupling and detuning problems in the wireless power transmission system of three coils, and proposes a compensation network structure and parameter determination method for a three-coil magnetic coupling system containing a relay coil. The method adds parallel compensation capacitors on the basis of maintaining the original compensation network structure, and through the design of compensation parameters, the system obtains different levels of constant voltage output characteristics and effectively reduces the capacity of the inverter. In this method, the relay coil does not work in a resonant state, and the system has only two resonant links, which is less likely to cause detuning problems than the traditional three-coil structure. At the same time, this method comprehensively considers the problem of cross-coupling, so that the system is fully compensated, thereby obtaining good output characteristics.

[0005] The main existing compensation network topologies are as follows:

[0006] 1. Transmitter, relay and receiving coil series capacitor compensation

[0007] By connecting capacitors in series with each coil to compensate, the resonant angular frequency of each coil loop is controlled at the same angular frequency, that is, Compensation topology such as Figure 1 As shown. Where L1 is the self-inductance of the transmitting coil, L r is the self-inductance of the relay coil, L2 is the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C1 is the compensation capacitor of the transmitting coil loop, and C r C is the compensation capacitor for the relay coil loop, and C2 is the compensation capacitor for the receiving coil loop.

[0008] According to the compensation topology, the KVL equations of the three loops are listed as follows:

[0009]

[0010] Its output characteristics are:

[0011]

[0012] From the output characteristic expression, it is not difficult to find that the output voltage of the load is difficult to control and is also related to the coupling parameters. The cross-coupling effect has not been eliminated. On the basis of the series capacitor resonance compensation of the transmitting, relaying and receiving coils, an impedance matching network or series reactance compensation is added, such as Figure 2-5 As shown, all of these are to eliminate the impact of cross-coupling and reduce reactive power.

[0013] In summary, the existing compensation method is to control the self-inductance of each coil to be consistent with the resonant frequency of the compensation capacitor to improve the energy transmission capacity of the system. However, with this compensation method, first, the output characteristics of the load are determined by the entire magnetic coupling system, and the internal reactance of the system cannot be fully compensated, and the output voltage regulation characteristics are poor. Second, the magnetic coupling system containing a relay coil in the application has three resonant frequencies, which is more prone to compensation network detuning problems than the two-coil system without a relay coil. Third, the magnetic coupling system containing a relay coil has a cross-coupling problem. The existing technology eliminates the influence of the cross-coupling effect by adding an impedance matching network or series reactance compensation on the basis of the resonant compensation network of each coil. However, this compensation method requires an increase in the number of devices, and once the output characteristics of the magnetic coupling system are given, they are completely determined, and different output characteristics cannot be obtained by designing the compensation network parameters. Summary of the invention

[0014] The purpose of the present invention is to provide a compensation network for wireless power transmission based on arbitrary constant voltage of a relay coil and a method for determining compensation parameters, so that the relay coil does not work in a resonant state. The system has only two resonant links, which is less prone to detuning problems than the traditional three-coil structure. Through the design of compensation parameters, the system obtains constant current output characteristics of different levels and effectively reduces the capacity of the inverter.

[0015] To achieve the above purpose, the technical solution of the present invention is: a compensation method for wireless power transmission based on arbitrary constant voltage of relay coil, based on the original compensation network, different levels of output constant voltage characteristics are obtained through parameter determination method, which is as follows:

[0016] Step A1: Equivalently transform the three-coil mutual inductance model into a transformer T model, wherein the three-coil mutual inductance model includes a transmitting coil loop, a relay coil loop, and a receiving coil loop;

[0017] Step A2: Transmitter coil loop compensation capacitor C s1 The equivalent leakage inductance L of the primary side in the transformer T model pk Series resonance, voltage source U of the transmitting coil loop in It is amplified by a transformer by n times and applied to the secondary side of the transformer T model. n is the equivalent transformation ratio of the transformer T model. This transformation ratio is different from the physical turns ratio of the transformer and can be any value in theory, including real and complex numbers.

[0018] Step A3: Receiving coil loop compensation capacitor C s2 The equivalent leakage inductance L of the secondary side in the transformer T model sk Series resonance, nU in Applied to the load located in the receiving coil loop to achieve constant voltage output, the parameters are determined as follows:

[0019]

[0020] Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency;

[0021] Step A4: According to the output current U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes;

[0022] When C s1When is infinite, At this time C s1 The capacitor can be replaced with a short circuit;

[0023] When C s2 When is infinite, At this time C s2 The capacitor can be replaced by a short circuit.

[0024] The present invention also provides an arbitrary constant voltage wireless power transmission compensation network based on a relay coil, comprising a transmitting coil loop, a relay coil loop, and a receiving coil loop, wherein the transmitting coil loop comprises a voltage source, a transmitting coil, and a transmitting coil loop compensation capacitor connected in series, the relay coil loop comprises a relay coil connected in series, and a relay coil loop compensation capacitor, the receiving coil loop comprises a receiving coil, a receiving coil loop series compensation capacitor, a receiving coil loop parallel compensation capacitor, and a load, one end of the receiving coil is connected to one end of the receiving coil loop parallel compensation capacitor and one end of the load via the receiving coil loop series compensation capacitor, and the other end of the receiving coil is connected to the other end of the receiving coil loop parallel compensation capacitor and the other end of the load.

[0025] The present invention also provides a compensation method for wireless power transmission based on arbitrary constant voltage of relay coils. Based on the above compensation network for wireless power transmission based on arbitrary constant voltage of relay coils, different levels of output constant voltage characteristics are obtained through parameter determination methods, as follows:

[0026] Step B1: Equivalent the three-coil mutual inductance model to a transformer T model;

[0027] Step B2: Transmitter coil loop compensation capacitor C s1 The equivalent leakage inductance L of the primary side in the transformer T model pk Series resonance, voltage source U in It is amplified by a transformer by n times and applied to the secondary side of the transformer T model. n is the equivalent transformation ratio of the transformer T model. This transformation ratio is different from the physical turns ratio of the transformer and can be any value in theory, including real and complex numbers.

[0028] Step B3: Connect compensation capacitor C in series with the receiving coil loop s2 The equivalent leakage inductance L of the secondary side in the transformer T model sk Series resonance, receiving coil loop parallel compensation capacitor C p Equivalent magnetizing inductance L of transformer T model m Parallel resonance reduces reactive power, nU in Applied to the load to achieve constant voltage output, the parameters are determined as follows:

[0029]

[0030] Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency;

[0031] Step B4: According to the output current U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes;

[0032] When C s1 When is infinite, At this time C s1 The capacitor can be replaced with a short circuit;

[0033] When C s2 When is infinite, At this time C s2 The capacitor can be replaced by a short circuit.

[0034] The present invention also provides another arbitrary constant voltage wireless power transmission compensation network based on a relay coil, comprising a transmitting coil loop, a relay coil loop, and a receiving coil loop, wherein the transmitting coil loop comprises a current source connected in parallel, a transmitting coil compensation capacitor, and a transmitting coil, the relay coil loop comprises a relay coil connected in series, a relay coil loop compensation capacitor, and the receiving coil loop comprises a receiving coil connected in series, a receiving coil loop series compensation capacitor, and a load.

[0035] The present invention also provides a compensation method for wireless power transmission based on arbitrary constant voltage of a relay coil. Based on the above compensation method for wireless power transmission based on arbitrary constant voltage of a relay coil, it is characterized in that, on the basis of the compensation network for wireless power transmission based on arbitrary constant voltage of a relay coil according to claim 2, different levels of output constant voltage characteristics are obtained by a parameter determination method, which is as follows:

[0036] Step C1: Equivalent the three-coil mutual inductance model to a transformer T model;

[0037] Step C2: Through equivalent source transformation, the current source is equivalent to a voltage source Transmitting coil compensation capacitor C p The equivalent leakage inductance L of the primary side in the transformer T model pk Series resonance, equivalent voltage source The voltage is amplified by a transformer by n times and applied to the secondary side of the transformer T model. pk With Lsk are the equivalent leakage inductances of the primary and secondary sides in the transformer T model, respectively; n is the equivalent transformation ratio of the transformer T model, which is different from the physical turns ratio of the transformer and can theoretically be any value, including real and complex numbers;

[0038] Step C3: Connect compensation capacitor C in series with the receiving coil loop s The equivalent leakage inductance L of the secondary side in the transformer T model sk Series resonance, equivalent source Applied to the load to achieve constant voltage output, the parameters are determined as follows:

[0039]

[0040] Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency;

[0041] Step C4: According to the output current U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes;

[0042] When C s When is infinite, At this time, the Cs capacitor can be replaced by a short line.

[0043] In one embodiment of the present invention, if the calculated required capacitance value is negative, inductance compensation is used. The relationship between the compensation inductance value and the negative compensation capacitance value is shown in the following formula:

[0044]

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The relay coil of the present invention does not work in a resonant state, and the system has only two resonant links, which is less likely to cause detuning problems than the traditional three-coil structure;

[0047] 2. The present invention comprehensively considers the problem of cross coupling, so that the system is fully compensated, thereby obtaining good output characteristics;

[0048] 3. The present invention enables the system to obtain constant voltage output characteristics of different levels and effectively reduces the capacity of the inverter through the design of compensation parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a compensation topology in which each coil is connected in series with capacitors for resonance.

[0050] Figure 2 It is a compensation topology that adds series reactance.

[0051] Figure 3 It is a compensation topology with an added 'I-type impedance matching network.

[0052] Figure 4 It is a compensation topology with a π-type impedance matching network added.

[0053] Figure 5 It is a compensation topology with a T-type impedance matching network added.

[0054] Figure 6 It is a three-coil mutual inductance model.

[0055] Figure 7 is the transformer T model.

[0056] Figure 8 It is the existing SSS compensation network structure.

[0057] Fig. 9 This is the SS compensation network structure 1 of the present invention.

[0058] Fig.10 This is the SS compensation network structure 2 of the present invention.

[0059] Fig.11 This is the SSSP compensation network structure of the present invention.

[0060] Fig.12 This is the SSP compensation network structure 1 of the present invention.

[0061] Fig.13 This is the SSP compensation network structure 2 of the present invention.

[0062] Fig.14 This is the PSS compensation network structure of the present invention.

[0063] Fig.15 This is the PS compensation network structure of the present invention.

[0064] Fig.16 This is the simulation result 1 of the embodiment of the present invention.

[0065] Fig.17 This is the second simulation result of the embodiment of the present invention.

[0066] Fig.18 This is the third simulation result of the embodiment of the present invention.

[0067] Fig.19It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0068] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0069] like Fig.11 As shown, the present invention provides a compensation network for wireless power transmission based on an arbitrary constant voltage of a relay coil, and a parallel compensation capacitor is added on the basis of maintaining the original compensation network structure, so that the system obtains constant voltage output characteristics of different levels and reduces the capacity of the inverter; specifically, it includes a transmitting coil loop, a relay coil loop, and a receiving coil loop, the transmitting coil loop includes a voltage source, a transmitting coil, and a transmitting coil loop compensation capacitor connected in series, the relay coil loop includes a relay coil connected in series, a relay coil loop compensation capacitor, the receiving coil loop includes a receiving coil, a receiving coil loop series compensation capacitor, a receiving coil loop parallel compensation capacitor, and a load, one end of the receiving coil is connected to one end of the receiving coil loop parallel compensation capacitor and one end of the load through the receiving coil loop series compensation capacitor, and the other end of the receiving coil is connected to the other end of the receiving coil loop parallel compensation capacitor and the other end of the load.

[0070] like Fig.14 As shown, the present invention provides a relay coil-based arbitrary constant voltage wireless power transmission compensation network, including a transmitting coil loop, a relay coil loop, and a receiving coil loop, wherein the transmitting coil loop includes a current source connected in parallel, a transmitting coil compensation capacitor, and a transmitting coil, the relay coil loop includes a relay coil connected in series, a relay coil loop compensation capacitor, and the receiving coil loop includes a receiving coil connected in series, a receiving coil loop compensation capacitor, and a load.

[0071] In this embodiment, based on the two-port characteristics, the original three-coil multi-level and complex mutual inductance model is equivalent to a simple and clear transformer T model, and its equivalent circuit model is as follows: Figure 7 The equivalent transformer T model "eliminates" the relay coil as a transfer station, and integrates the coupling relationship of each coil into Lpk, Lsk, Lm, n in the transformer T model.

[0072] According to KVL, the voltage equations of each circuit are listed:

[0073]

[0074]

[0075] Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, Mr2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency, which is different from ω0.

[0076] The matrix expression is also obtained:

[0077]

[0078] L pk With L sk are the equivalent leakage inductances of the primary and secondary sides of the transformer T model, respectively. n is the equivalent transformation ratio of the transformer T model. This transformation ratio is different from the physical turns ratio of the transformer. Theoretically, it can be any value (including real and complex numbers). L m is the equivalent magnetizing inductance of the transformer T model.

[0079] To ensure the same two-port characteristics, the relationship between the parameters in the transformer T model and the parameters in the mutual inductance model is as follows:

[0080]

[0081] L1, L2, L r , M 1r , M r2 , M 12 can be obtained through actual measurement, and the relay coil compensation capacitor C r Select Not Equal (ω0 represents the inherent resonant angular frequency), that is, the relay coil is in a detuned condition. From the expression, it can be seen that with the magnetic coupling structure of the wireless power transmission system and the compensation capacitor C r The value is fixed, L m , L pk , L sk can be determined by different n. The equivalent transformer T model is placed in the wireless power transmission system. The equivalent transformer T model is an equivalent method based on the detuned condition of the relay coil. It not only integrates the cross-coupling into the equivalent model and realizes the decoupling of the relay coil, but also provides a new way to eliminate the cross-coupling.

[0082] In the embodiment of the present invention, Figure 8 The compensation network structure shown in the figure is based on the original three-coil magnetic coupling system, and its parameter determination method includes the following steps:

[0083] Step A1: Equivalent the three-coil mutual inductance model to a transformer T model;

[0084] Step A2: C s1 With L pkSeries resonance, voltage source U in Amplified by n times through the transformer and applied to the secondary side, L pk With L sk are the equivalent leakage inductances of the primary and secondary sides in the transformer T model, respectively; n is the equivalent transformation ratio of the transformer T model (this transformation ratio is different from the physical turns ratio of the transformer and can be any value in theory, including real and complex numbers);

[0085] Step A3: C s2 With L sk Series resonance, nU in Applied to the output load to achieve constant voltage output, the parameters are determined as follows:

[0086]

[0087] Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency;

[0088] Step A4: According to the output current U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes;

[0089] When C s1 When is infinite, At this time C s1 The capacitor can be replaced by a short circuit, such as Fig. 9 As shown;

[0090] When C s2 When is infinite, At this time C s2 The capacitor can be replaced by a short circuit, such as Fig.10 shown.

[0091] In the embodiment of the present invention, Fig.11 The compensation network structure based on the three-coil magnetic coupling system shown in the figure, and its parameter determination method, include the following steps:

[0092] Step B1: Equivalent the three-coil mutual inductance model to a transformer T model;

[0093] Step B2: C s1 With L pk Series resonance, voltage source U inAmplified by n times through the transformer and applied to the secondary side, L pk With L sk are the equivalent leakage inductance of the primary and secondary sides in the transformer T model, L m is the equivalent magnetizing inductance of the transformer T model, n is the equivalent transformation ratio of the transformer T model (this transformation ratio is different from the physical turns ratio of the transformer and can be any value in theory, including real and complex numbers);

[0094] Step B3: C s2 With L sk Series resonance, C p With L m Parallel resonance reduces reactive power, nU in Applied to the output load to achieve constant voltage output, the parameters are determined as follows:

[0095]

[0096] Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency;

[0097] Step B4: According to the output current U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes;

[0098] When C s1 When is infinite, At this time C s1 The capacitor can be replaced by a short circuit, such as Fig.12 As shown;

[0099] When C s2 When is infinite, At this time C s2 The capacitor can be replaced by a short circuit, such as Fig.13 shown.

[0100] In the embodiment of the present invention, Fig.14 The compensation network structure based on the three-coil magnetic coupling system shown in the figure, and its parameter determination method, include the following steps:

[0101] Step C1: Equivalent the three-coil mutual inductance model to a transformer T model;

[0102] Step C2: Through equivalent source transformation, the current source is equivalent to a voltage source C p With L pk Series resonance, equivalent voltage source Amplified by a transformer n times and applied to the secondary side, L pk With L sk are the equivalent leakage inductances of the primary and secondary sides in the transformer T model, respectively; n is the equivalent transformation ratio of the transformer T model (this transformation ratio is different from the physical turns ratio of the transformer and can be any value in theory, including real and complex numbers);

[0103] Step C3: C s With L sk Series resonance, equivalent source Applied to the output load to achieve constant voltage output, the parameters are determined as follows:

[0104]

[0105] Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency;

[0106] Step C4: According to the output current U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes;

[0107] When C s When is infinite, At this time C s The capacitor can be replaced by a short circuit, such as Fig.15 shown.

[0108] In this embodiment, if the calculated required capacitance value is negative, inductance compensation is used. The relationship between the compensation inductance value and the negative compensation capacitance value is shown in the following formula:

[0109]

[0110] Reference Figure 8 , embodiments of the present invention:

[0111] For a three-coil wireless power transmission system operating at a frequency of 100kHz, the self-inductance of the transmitting coil of the magnetic coupling structure is 240uH, the self-inductance of the relay coil is 200uH, and the self-inductance of the pickup coil is 100uH. 1r =0.11, K r2 =0.285, K 12 =0.053, relay coil resonant capacitance C r Select To characterize the detuning condition of the relay coil, the amplitude of the inverter input source connected to the transmitting coil is 100V, and the compensation method is as follows:

[0112] When the required output amplitude is 100V, that is, the transformation ratio n=1, the formula is used to calculate C s1 and C s2 , at this time C s1 =11.82nF, C s2 =20.9nF, the output side can achieve the effect of constant voltage output 100V. The simulation results are as follows Fig.16 As shown;

[0113] When the required output amplitude is 150V, that is, the transformation ratio n=1.5, the C s1 and C s2 , at this time C s1 =10.94nF, C s2 =26.6nF, the output side can achieve the effect of constant voltage output 150V. The simulation results are as follows Fig.17 As shown;

[0114] When the required output amplitude is 400V, that is, the transformation ratio n=4, the formula is used to calculate C s1 and C s2 , at this time C s1 =10.0nF, C s2 =-72.99nF is a negative value. Apply the formula and select the inductor L s2 =34.70uH instead of C s2 At this time, the output side can achieve the effect of constant voltage output of 400V. The simulation results are as follows Fig.18 shown.

[0115] Fig.19 It is an overall flow chart of the method of the present invention.

[0116] The above are preferred embodiments of the present invention. Any changes made according to the technical solution of the present invention, as long as the resulting functions do not exceed the scope of the technical solution of the present invention, belong to the protection scope of the present invention.

Claims

1. A compensation method for wireless power transmission based on arbitrary constant voltage of relay coil, characterized in that: Based on a relay coil arbitrary constant voltage wireless power transmission compensation network, different levels of output constant voltage characteristics are obtained through a parameter determination method, the compensation network includes a transmitting coil loop, a relay coil loop, and a receiving coil loop, the transmitting coil loop includes a current source connected in parallel, a transmitting coil compensation capacitor, and a transmitting coil, the relay coil loop includes a relay coil connected in series, a relay coil loop compensation capacitor, and the receiving coil loop includes a receiving coil connected in series, a receiving coil loop series compensation capacitor, and a load, and the method is specifically as follows: Step A1: Equivalently transform the three-coil mutual inductance model into a transformer T model, wherein the three-coil mutual inductance model includes a transmitting coil loop, a relay coil loop, and a receiving coil loop; Step A2: Transmitter coil loop compensation capacitor C s1 The equivalent leakage inductance L of the primary side in the transformer T model pk Series resonance, voltage source U of the transmitting coil loop in The voltage is amplified by n times through the transformer and applied to the secondary side of the transformer T model. n is the equivalent transformation ratio of the transformer T model, which is different from the physical turns ratio of the transformer. Step A3: Receiving coil loop compensation capacitor C s2 The equivalent leakage inductance L of the secondary side in the transformer T model sk Series resonance, nU in Applied to the load located in the receiving coil loop to achieve constant voltage output, the parameters are determined as follows: Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency; Step A4: According to the output voltage U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes; When C s1 When is infinite, At this time C s1 The capacitor is replaced with a short circuit; When C s2 When is infinite, At this time C s2 The capacitor is replaced with a short circuit.

2. A compensation method for wireless power transmission based on arbitrary constant voltage of relay coil, characterized in that: Based on a compensation network for wireless power transmission with arbitrary constant voltage based on a relay coil, different levels of output constant voltage characteristics are obtained by a parameter determination method, wherein the compensation network includes a transmitting coil loop, a relay coil loop, and a receiving coil loop, wherein the transmitting coil loop includes a voltage source, a transmitting coil, and a transmitting coil loop compensation capacitor connected in series, wherein the relay coil loop includes a relay coil connected in series, and a relay coil loop compensation capacitor, wherein the receiving coil loop includes a receiving coil, a receiving coil loop series compensation capacitor, a receiving coil loop parallel compensation capacitor, and a load, wherein one end of the receiving coil is connected to one end of the receiving coil loop parallel compensation capacitor and one end of the load via the receiving coil loop series compensation capacitor, and the other end of the receiving coil is connected to the other end of the receiving coil loop parallel compensation capacitor and the other end of the load, wherein the method is specifically as follows: Step B1: Equivalent the three-coil mutual inductance model to a transformer T model; Step B2: Transmitter coil loop compensation capacitor C s1 The equivalent leakage inductance L of the primary side in the transformer T model pk Series resonance, voltage source U in The voltage is amplified by n times through the transformer and applied to the secondary side of the transformer T model. n is the equivalent transformation ratio of the transformer T model, which is different from the physical turns ratio of the transformer. Step B3: Connect compensation capacitor C in series with the receiving coil loop s2 The equivalent leakage inductance L of the secondary side in the transformer T model sk Series resonance, receiving coil loop parallel compensation capacitor C p Equivalent magnetizing inductance L of transformer T model m Parallel resonance reduces reactive power, nU in Applied to the load to achieve constant voltage output, the parameters are determined as follows: Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency; Step B4: According to the output voltage U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes; When C s1 When is infinite, At this time C s1 The capacitor is replaced with a short circuit; When C s2 When is infinite, At this time C s2 The capacitor is replaced with a short circuit.

3. A compensation method for wireless power transmission based on arbitrary constant voltage of relay coil, characterized in that: Based on a relay coil arbitrary constant voltage wireless power transmission compensation network, different levels of output constant voltage characteristics are obtained through a parameter determination method, the compensation network includes a transmitting coil loop, a relay coil loop, and a receiving coil loop, the transmitting coil loop includes a current source connected in parallel, a transmitting coil compensation capacitor, and a transmitting coil, the relay coil loop includes a relay coil connected in series, a relay coil loop compensation capacitor, and the receiving coil loop includes a receiving coil connected in series, a receiving coil loop series compensation capacitor, and a load, and the method is specifically as follows: Step C1: Equivalent the three-coil mutual inductance model to a transformer T model; Step C2: Through equivalent source transformation, the current source is equivalent to a voltage source Transmitting coil compensation capacitor C p The equivalent leakage inductance L of the primary side in the transformer T model pk Series resonance, equivalent voltage source The voltage is amplified by a transformer by n times and applied to the secondary side of the transformer T model. pk With L sk are the equivalent leakage inductances of the primary and secondary sides in the transformer T model, respectively; n is the equivalent transformation ratio of the transformer T model, which is different from the physical turns ratio of the transformer; Step C3: Connect compensation capacitor C in series with the receiving coil loop s The equivalent leakage inductance L of the secondary side in the transformer T model sk Series resonance, equivalent source Applied to the load to achieve constant voltage output, the parameters are determined as follows: Among them, L1, L r , L2 are the self-inductance of the transmitting coil, the self-inductance of the relay coil and the self-inductance of the receiving coil, M 1r is the mutual inductance between the transmitting coil and the relay coil, M r2 is the mutual inductance between the relay coil and the receiving coil, M 12 is the mutual inductance between the transmitting coil and the receiving coil, C r is the compensation capacitor of the relay coil loop, ω is the system operating angular frequency; Step C4: According to the input voltage U RL Size, that is, determine the value of n, and further determine the required capacitance value to achieve the required voltage gain and not change with load changes; When C s When is infinite, At this time, the Cs capacitor is replaced by a short circuit.

4. A method for wireless power transmission compensation based on arbitrary constant voltage of a relay coil according to any one of claims 1 to 3, characterized in that: If the required capacitance value is calculated to be negative, inductance compensation is used. The relationship between the compensation inductance value and the negative compensation capacitance value is shown in the following formula:

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