Dual-mode compensation topology circuit with strong anti-offset characteristic and parameter design method

Abstract

The application relates to a dual-mode compensation topology circuit with strong anti-deviation characteristics and a parameter design method, and belongs to the technical field of megahertz wireless power transmission. In view of the problem that the T-shaped impedance matching network of a class-E power amplifier in an existing wireless power transmission system cannot meet the design requirements of wide-range anti-deviation, the application comprises a class-E power amplifier, a resonance compensation network, a coupling coil and a rectifier, the input end of the class-E power amplifier is connected with a power supply V dc , the output end of the class-E power amplifier is connected with the input end of the resonance compensation network, the output end of the resonance compensation network is connected with the primary side input end of the coupling coil, and the secondary side output end of the coupling coil is connected with the input end of the rectifier; the switching of a weak coupling mode and a strong coupling mode is realized through the access and short circuit of elements in the resonance compensation network. The application can keep the high-efficiency operation of each link of the system within a wide coupling coefficient variation range.

Description

Technical Field

[0001] This invention relates to a dual-mode compensation topology circuit with strong anti-offset characteristics and a parameter design method, belonging to the field of megahertz wireless power transmission technology. Background Technology

[0002] Wireless power transfer refers to the process of transferring energy from the primary side to the secondary side using an alternating electromagnetic field. Typically, a resonant circuit is used to convert electrical energy into magnetic energy, which is then transferred to the receiver. The magnetic energy is then converted back into electrical energy through electromagnetic induction, thus achieving wireless power transfer. Traditional wireless power transfer mainly uses low- to mid-frequency electromagnetic fields, such as in the charging of common consumer electronic devices. Megahertz wireless power transfer is a novel wireless power transfer method. Its switching devices operate in the megahertz frequency band, which can reduce the size of devices and coils. While increasing power density, efficiency can approach the level of traditional wireless power transfer. With proper circuit design, longer-distance transmission can be achieved, and it has stronger coil position tolerance. Therefore, megahertz wireless power transfer has broad application potential in scenarios where coil positions are not fixed and charging circuit space is limited.

[0003] In traditional low-to-medium frequency wireless power transmission, the coupling coefficient between the transmitting and receiving coils changes with their positions, requiring strict coil alignment to maintain a stable resonant state. If the coils deviate from their designated positions, the compensation topology designed based on the resonant state will lose its original resonance, resulting in the loss of the system's input-output characteristics and inability to meet load requirements. More seriously, changes in coil position also lead to significant losses, drastically reducing circuit reliability. This reliability issue is even more pronounced in high-frequency wireless power transmission because capacitors and inductors in high-frequency circuits are more sensitive, requiring higher precision and stability to achieve ideal power output.

[0004] In series compensation, configuring a resonant capacitor makes the reactance component of the secondary side zero, ensuring optimal coil efficiency. Adding a small resonant capacitor has minimal impact on the secondary power density, hence series compensation is widely used in the coil section of megahertz wireless power transfer systems. In recent years, the mainstream solution for the primary-side inverter section of megahertz wireless power transfer systems is the Class E power amplifier. This is a high-efficiency RF amplifier commonly used in communication and radar applications, characterized by fewer circuit components, ease of driving, and high efficiency. However, Class E power amplifiers are highly load-sensitive, and their efficient operation depends on precise load impedance matching, a problem that severely limits their wide load range application. A common solution is to design compensation circuits based on specific application scenarios, such as adding an impedance matching network between the coil section and the Class E power amplifier. Specifically, impedance matching networks can be divided into static and dynamic, passive and active matching networks. Dynamic and active matching networks are usually complex to design, resulting in low power density, and are currently only in the proof-of-concept stage. Examples include capacitor matrices and variable inductors. Static, passive matching networks are widely used, but because their parameters are fixed, their matching capabilities are limited, making it difficult to achieve ideal results. For example, a T / Π network composed of resonant capacitors and inductors. Using static, passive networks for impedance matching can enable megahertz wireless power transmission systems to meet certain constant voltage and constant current design requirements, but it presents inherent design challenges for wide-range offset resistance. Summary of the Invention

[0005] To address the problem that the T-type impedance matching network of Class E power amplifiers in existing wireless power transmission systems cannot meet the wide-range anti-offset design requirements, this invention provides a dual-mode compensation topology circuit and parameter design method with strong anti-offset characteristics.

[0006] This invention includes four technical solutions:

[0007] Option 1: A dual-mode compensation topology circuit with strong anti-offset characteristics, including a Class E power amplifier, a resonant compensation network, a coupling coil, and a rectifier.

[0008] The input of a Class E power amplifier is connected to a power supply V. dc The output of the Class E power amplifier is connected to the input of the resonant compensation network, the output of the resonant compensation network is connected to the primary input of the coupling coil, and the secondary output of the coupling coil is connected to the input of the rectifier.

[0009] Class E power amplifiers include inductors L f Switch Q, capacitor Cs, capacitor C0, inductor L0, power supply V dc The positive terminal is connected to the inductor L f One end, inductor L fThe other end is connected to the drain of the switching transistor Q, and the source of the switching transistor Q is connected to the power supply V. dc The negative terminal of the capacitor is grounded; the capacitor Cs is connected in parallel with the switch Q, the drain of the switch Q is connected to one end of the capacitor C0, and the other end of the capacitor C0 is connected to one end of the inductor L0.

[0010] The resonant compensation network includes inductor X T1 Reactance X T2 and capacitor X T3 Inductor X T1 One end corresponds to the other end of inductor L0, and inductor X T1 The other end is connected to reactor X T2 One end, reactance X T2 The other end serves as an output terminal of the resonant compensation network, capacitor X T3 One end is connected to inductor X T1 and reactance X T2 Between, capacitance X T3 The other end serves as the other output of the resonant compensation network;

[0011] In weak coupling mode, the other end of inductor L0 replaces one output of the resonant compensation network and is connected to one primary input of the coupling coil.

[0012] In strong coupling mode, make inductor X T1 One end is connected to the other end of inductor L0, and the reactance X T2 The other end is connected to one primary input terminal of the coupling coil; simultaneously, the reactance X T2 The value is 0.

[0013] According to the present invention, the dual-mode compensation topology circuit with strong anti-offset characteristics switches between weak coupling mode and strong coupling mode through a single-pole double-throw relay.

[0014] Option 2: A parameter design method for a dual-mode compensation topology circuit with strong anti-offset characteristics, which involves parameter design of the dual-mode compensation topology circuit with strong anti-offset characteristics described in Option 1, including equivalent load of the Class E power amplifier;

[0015] The effect of the rectifier on the Class E power amplifier can be equivalently expressed as the fundamental input impedance Z. rec :

[0016] Z rec =R rec +jX rec (1)

[0017] In the formula R rec X is the equivalent resistance component of the rectifier. rec This is the equivalent reactance component of the rectifier;

[0018] The self-inductance of the coupling coil and the transmitting coil is L. tx The self-inductance of the coupling coil receiving coil is L. rx L rx The capacitor C connected in series with it rx If the reactance component of the secondary side of the coupling coil is compensated together, then the total reactance compensation amount X on the secondary side is... rx for:

[0019]

[0020] In the formula, ω is the angular frequency;

[0021] Then the total input impedance Z on the secondary side RX for:

[0022] Z RX =R rec +r rx +j(X rec +X rx (3)

[0023] In the formula r rx The resistance of the receiving coil;

[0024] In the equivalent circuit model of a loosely coupled voltage transformer composed of coupled coils, the effect of the secondary side on the primary side is represented by the reflection impedance Z connected in series with the transmitting coil. ref Equivalent to:

[0025] Z ref =R ref +jX ref (4)

[0026] In the formula R ref The reflection impedance Z ref The resistive component, X ref The reflection impedance Z ref Reactance component:

[0027]

[0028]

[0029] In the formula, M is the mutual inductance of the loosely coupled voltage transformer;

[0030] Similar to the receiving coil, the self-inductance L of the coupling coil and the transmitting coil is... tx The capacitor C connected in series with it tx Together they are considered as the total primary reactance compensation amount X tx :

[0031]

[0032] Then the overall input impedance Z of the coupled coil is obtained.coil :

[0033] Z coil =Z ref +jX tx +r rx (8)

[0034] The parameter design method for a dual-mode compensated topology circuit with strong anti-offset characteristics according to the present invention, in the weakly coupled mode, includes parameter design:

[0035] Based on the parameters of the Class E power amplifier, the amplifier load impedance Z PA Simulation parameter scanning yields contour lines for amplifier output power and efficiency; the amplifier load impedance Z is then determined from these contour lines. PA The target region corresponding to the design objective, wherein the varying amplifier load impedance Z PA Maintain stable output power in the target area;

[0036] Make the overall input impedance Z of the coupling coil coil If the trajectory is within the target area, then:

[0037] Z PA =Z coil (9)

[0038] The overall input impedance Z of the coupled coil coil Incomplete compensation will be provided.

[0039] The minimum mutual inductance M under the condition of minimum coupling between the transmitting coil and the receiving coil min The corresponding minimum coupled coil overall input impedance Z coil,min Set at one edge of the target area to make the target area encompass a wider range of variations in the mutual inductance M of the loosely coupled voltage transformers, based on the minimum mutual inductance M. min and the overall input impedance Z of the minimum coupled coil coil,min The total secondary reactance compensation amount X is calculated. rx Total reactance compensation amount X tx .

[0040] According to the design method of the dual-mode compensated topology circuit with strong anti-offset characteristics of the present invention, the total secondary reactance compensation amount X rx Total reactance compensation amount X tx The calculation method is as follows:

[0041]

[0042]

[0043] In the formula R coil.minThe overall input impedance Z of the minimum coupled coil coil,min The resistive component, X coil.min The overall input impedance Z of the minimum coupled coil coil,min The reactive component;

[0044] Z coil,min =R coil.min +jX coil.min .

[0045] The parameter design method for a dual-mode compensated topology circuit with strong anti-offset characteristics according to the present invention, in the case of parameter design under strongly coupled mode:

[0046] Make the overall input impedance Z of the coupling coil coil Converted to impedance Z T ,but:

[0047] Z PA =Z T (12)

[0048] From inductor X T1 and capacitor X T3 Determine the impedance Z T Maximum coupling load point Z T,max The position of the point Z with maximum coupling load. T,max Overall input impedance Z of the minimum coupled coil coil,min The overlap ensures that the Class E power amplifiers at the two boundary points of the target region have the same operating state;

[0049] For resonant compensation networks:

[0050]

[0051] In the formula Z coil,max This represents the overall input impedance of the maximum coupling coil;

[0052] By: Z T,max =Z coil,min (14)

[0053] Obtain the parameters of the resonant compensation network:

[0054]

[0055]

[0056] In the formula X coil,max The overall input impedance Z of the maximum coupled coil coil,max The reactance component, R coil,max The overall input impedance Z of the maximum coupled coil coil,max The resistive component.

[0057] Option 3: A dual-mode compensation topology circuit with strong anti-offset characteristics, based on the dual-mode compensation topology circuit with strong anti-offset characteristics described in Option 1, replacing inductors L0 and X with a combined inductor composed of inductors L1 and L2. T1 Reactance X T2 Set to 0;

[0058] In weak coupling mode, the center tap of the inductor is connected to one primary input terminal of the coupling coil, short-circuiting inductor L2 and capacitor X. T3 Disconnect from the circuit; in strong coupling mode, unshort-circuit inductor L2 and capacitor X. T3 Connect to the circuit.

[0059] According to the present invention, the dual-mode compensation topology circuit with strong anti-offset characteristics switches between weak coupling mode and strong coupling mode through a single-pole double-throw relay.

[0060] Option 4: A parameter design method for a dual-mode compensation topology circuit with strong anti-offset characteristics. This method designs the parameters of the dual-mode compensation topology circuit with strong anti-offset characteristics described in Option 3, and further designs the parameters of inductors L1 and L2 based on the parameter design method for the dual-mode compensation topology circuit with strong anti-offset characteristics described in Option 2.

[0061] In strong coupling mode, inductors L1 and L2 are coupled, and the combined inductance is equal to L0 and X. T1 In series, then:

[0062] L0+X T1 =L1+L2+2M 12 (17)

[0063] In the formula M 12 The mutual inductance of inductors L1 and L2;

[0064] In the weakly coupled mode, R L1 As the parasitic resistance of inductor L1, R L2 As the parasitic resistance of inductor L2, we obtain the following equations:

[0065]

[0066] In the formula, U is the voltage across the inductor;

[0067] Parasitic resistance R omitted L1 and parasitic resistance R L2 Based on the equivalent circuit of the inductor in the weakly coupled mode, we obtain:

[0068]

[0069] In the formula I in The input current is the combined inductor.

[0070] The values ​​of inductance L1 and inductance L2 are calculated using formulas (17) and (19).

[0071] The beneficial effects of this invention are as follows: The novel dual-mode compensation topology with strong anti-migration capability provided by this invention can compress the changes in system output characteristics caused by changes in the relative positions of the transmitting and receiving coils, significantly enhancing the anti-migration capability of the wireless power transmission system. In the parameter design method, the impedance matching network can be switched by adding only one relay. The variable compensation topology of this invention, under strong and weak coupling mode switching, can maintain the efficient operation of all components of the system within a wide range of coupling coefficient variations, solving the problem of system efficiency degradation. Attached Figure Description

[0072] Figure 1 This is a circuit diagram of the megahertz wireless power transmission system in Specific Implementation Method 1;

[0073] Figure 2 yes Figure 1 The circuit diagram for switching between weakly coupled and strongly coupled modes;

[0074] Figure 3 Z is a different coil compensation scheme in specific implementation method two. coil A diagram illustrating the matching status of the target region;

[0075] Figure 4 This is an analysis of the primary coil efficiency of different compensation schemes in the second specific implementation method;

[0076] Figure 5 This is a circuit diagram of the dual-mode compensation topology in specific implementation method three;

[0077] Figure 6 This is the equivalent circuit diagram of the weakly coupled mode set inductor in the circuit parameter design process of Implementation Method 4.

[0078] Figure 7 This is the overall flowchart for circuit parameter design in Implementation Method 4;

[0079] Figure 8 This is the load impedance trajectory diagram of the power amplifier in the simulation experiment;

[0080] Figure 9 This is the simulation result of the overall efficiency of the system under constant output voltage in the simulation experiment;

[0081] Figure 10 It is the simulation result of the input voltage of the system under constant output voltage in the simulation experiment;

[0082] Figure 11 These are experimental results showing the variation of system efficiency with coupling coefficient in a specific embodiment; Ewpt in the figure represents system efficiency.

[0083] Figure 12 These are experimental results showing the variation of the system input voltage with the coupling coefficient in a specific embodiment;

[0084] Figure 13 In a specific embodiment, at the switching point k = 0.227 between weak and strong coupling, the source voltage V of the Class E power amplifier switch before switching is... GS and drain-source voltage V DS The waveform, Time represents time; 50.0ns / div means each division is 50ns;

[0085] Figure 14 In a specific embodiment, at the switching point k = 0.227 between weak and strong coupling, the source voltage (V) of the Class E power amplifier switching transistor after switching is... GS ) and drain-source voltage (V DS The waveform of )

[0086] Figure 15 The input and output voltage waveforms are shown when switching from weak to strong coupling, to change the relative position of the coils; Vo in the figure represents the system output voltage.

[0087] Figure 16 The input and output voltage waveforms during the switching from strong coupling to weak coupling are shown in the diagram to change the relative position of the coils. Detailed Implementation

[0088] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0089] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0090] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0091] Specific Implementation Method 1: Combination Figure 1 and Figure 2 As shown, this embodiment provides a dual-mode compensation topology circuit with strong anti-offset characteristics, including a Class E power amplifier, a resonant compensation network, a coupling coil, and a rectifier.

[0092] The input of a Class E power amplifier is connected to a power supply V. dc The output of the Class E power amplifier is connected to the input of the resonant compensation network, the output of the resonant compensation network is connected to the primary input of the coupling coil, and the secondary output of the coupling coil is connected to the input of the rectifier.

[0093] Class E power amplifiers include inductors L f Switch Q, capacitor Cs, capacitor C0, inductor L0, power supply V dc The positive terminal is connected to the inductor L f One end, inductor L f The other end is connected to the drain of the switching transistor Q, and the source of the switching transistor Q is connected to the power supply V. dc The negative terminal of the capacitor is grounded; the capacitor Cs is connected in parallel with the switch Q, the drain of the switch Q is connected to one end of the capacitor C0, and the other end of the capacitor C0 is connected to one end of the inductor L0.

[0094] The resonant compensation network includes inductor X T1 Reactance X T2 and capacitor X T3 Inductor X T1 One end corresponds to the other end of inductor L0, and inductor X T1 The other end is connected to reactor X T2 One end, reactance X T2 The other end serves as an output terminal of the resonant compensation network, capacitor X T3 One end is connected to inductor X T1 and reactance X T2 Between, capacitance X T3 The other end serves as the other output of the resonant compensation network;

[0095] In weak coupling mode, the other end of inductor L0 replaces one output of the resonant compensation network and is connected to one primary input of the coupling coil.

[0096] In strong coupling mode, make inductor X T1 One end is connected to the other end of inductor L0, and the reactance X T2 The other end is connected to one primary input terminal of the coupling coil; simultaneously, the reactance X T2 The value is 0.

[0097] Furthermore, such as Figure 2 As shown, the switching between weakly coupled mode and strongly coupled mode is achieved through a single-pole double-throw relay.

[0098] Specific Implementation Method Two: Combination Figures 1 to 4As shown, this embodiment provides a parameter design method for a dual-mode compensation topology circuit with strong anti-offset characteristics. The parameter design of the dual-mode compensation topology circuit with strong anti-offset characteristics described in Specific Embodiment 1 includes equivalent load of the Class E power amplifier.

[0099] Figure 1 This is a circuit diagram of a megahertz wireless power transfer system based on a Class E power amplifier. Typically, the high-frequency rectifier connected to the resonant coupling coil has low harmonic content, and its harmonic impedance can be ignored. Therefore, the influence of the secondary rectifier section can be equivalently expressed as the fundamental input impedance Z. rec .

[0100] Under high-frequency conditions, the parasitic capacitance of the rectifier diodes cannot be ignored, leading to Z rec There will also be a reactive component. Therefore, the effect of the rectifier on the Class E power amplifier can be equivalently expressed as the fundamental input impedance Z. rec :

[0101] Z rec =R rec +jX rec (1)

[0102] In the formula R rec X is the equivalent resistance component of the rectifier. rec This is the equivalent reactance component of the rectifier;

[0103] In the coupling coil section, the self-inductance of the coupling coil transmitting coil is L. tx The self-inductance of the coupling coil receiving coil is L. rx Their values ​​are negligible due to variations in the coupling coefficient. In series compensation, L rx The capacitor C connected in series with it rx If the reactance component of the secondary side of the coupling coil is compensated together, then the total reactance compensation amount X on the secondary side is... rx for:

[0104]

[0105] In the formula, ω is the angular frequency;

[0106] The total input impedance Z of the secondary side after series compensation RX for:

[0107] Z RX =R rec +r rx +j(X rec +X rx (3)

[0108] In the formula r rx The resistance of the receiving coil;

[0109] In the equivalent circuit model of a loosely coupled voltage transformer composed of coupled coils, the effect of the secondary side on the primary side is represented by the reflection impedance Z connected in series with the transmitting coil. ref Equivalent to:

[0110] Z ref =R ref +jX ref (4)

[0111] In the formula R ref The reflection impedance Z ref The resistive component, X ref The reflection impedance Z ref Reactance component:

[0112]

[0113]

[0114] In the formula, M is the mutual inductance of the loosely coupled voltage transformer;

[0115] Similar to the receiving coil, the self-inductance L of the coupling coil and the transmitting coil is... tx The capacitor C connected in series with it tx Together they are considered as the total primary reactance compensation amount X tx :

[0116]

[0117] Then the overall input impedance Z of the coupled coil is obtained. coil :

[0118] Z coil =Z ref +jX tx +r rx (8)

[0119] A common compensation configuration for coil sections is to utilize X rx X rectifier reactance re With complete compensation, according to equations (3) to (6), Z is at this time RX and Z ref This is purely resistive, which optimizes the coil's efficiency. Let L on the primary side... tx and C tx Complete resonance makes X tx It is zero. According to (8), Z... coil It is also purely resistive.

[0120] Furthermore, parameter design in the weakly coupled mode:

[0121] Once the parameters of the Class E power amplifier (as shown in Table 1) are determined, the amplifier load impedance Z is adjusted according to these parameters. PA Simulation parameter scanning yields contour lines for amplifier output power and output efficiency; such as Figure 3 As shown. The design objective for load impedance can be described as follows: Figure 3 The shaded area in the diagram, i.e., the varying load point, maintains a relatively stable output power within the high-efficiency range. By employing appropriate measures, Z... coil If the trajectory is within the target area, the coil section can be directly connected to the power amplifier.

[0122] Table 1 Class E Power Amplifier Parameters

[0123]

[0124] The amplifier load impedance Z is determined by the contour lines of amplifier output power and output efficiency. PA The target region corresponding to the design objective, wherein the varying amplifier load impedance Z PA Maintain stable output power in the target area;

[0125] Make the overall input impedance Z of the coupling coil coil If the trajectory is within the target area, then:

[0126] Z PA =Z coil (9)

[0127] With complete coil compensation, Z changes with mutual inductance coil like Figure 3 The first trajectory from the bottom is shown in the figure. Note that the real part of the reflection impedance R in expression (6) is... ref There is a square relationship between mutual inductance and the value of mutual inductance, therefore, the value of mutual inductance increases by Z. coil Moving to the right along the pure resistance line, its trajectory clearly deviates from the target region. The second trajectory from the bottom represents only increasing X... tx Z-axis of the primary coil is obtained with incomplete compensation coil Its trajectory curve rotates clockwise to a certain extent along the isostatic circle based on the fully compensated trajectory. However, it can be seen that neither of them achieved matching of the target region.

[0128] In this embodiment, incomplete compensation is performed in the series compensation of the secondary coil, and retaining a small part of the reactance component can achieve a better matching effect.

[0129] The overall input impedance Z of the coupled coil coil Incomplete compensation: Consider X ref The expression (6) further reduces X on the basis of full compensation. rxThis makes the overall impedance of the secondary side capacitive. Thus, Z ref The imaginary part is positive and decreases as mutual inductance decreases. Based on the characteristics of the target load region, this parameter configuration makes Z... ref This achieves a trend towards constant power within the high-efficiency range. Similarly, combined with X... tx Z ref Rotate the entire assembly to the target region, noting that this does not change the trend of the reactance component decreasing as mutual inductance decreases. The final achievable effect is as follows: Figure 3 As shown in the topmost trajectory, the mutual inductance values ​​corresponding to this impedance trajectory also increase from left to right. The minimum mutual inductance M under the condition of minimum coupling between the transmitting and receiving coils is... min The corresponding minimum coupled coil overall input impedance Z coil,min Set at one edge of the target area to make the target area encompass a wider range of variations in the mutual inductance M of the loosely coupled voltage transformers, based on the minimum mutual inductance M. min and the overall input impedance Z of the minimum coupled coil coil,min The total secondary reactance compensation amount X is calculated. rx Total reactance compensation amount X tx The reasonable solution here is obtained by taking the minus sign.

[0130] Secondary side total reactance compensation X rx Total reactance compensation amount X tx The calculation method is as follows:

[0131]

[0132]

[0133] In the formula R coil.min The overall input impedance Z of the minimum coupled coil coil,min The resistive component, X coil.min The overall input impedance Z of the minimum coupled coil coil,min The reactive component;

[0134] Z coil,min =R coil.min +jX coil.min .

[0135] Using a partial compensation scheme will reduce the efficiency of the coil, so it is necessary to consider whether this sacrifice is acceptable. The parameters of the coil are listed in Table 2, corresponding to Z... coil The isoefficiency curve of the primary coil with variable is as follows: Figure 4 As shown, Figure 4 The meaning of the three impedance trajectories and Figure 3The results are the same as in the previous section. It can be seen that the coil efficiency of all three schemes decreases as the mutual inductance decreases, and the efficiency difference between the incomplete and complete compensation schemes is very small. Therefore, to a certain extent, it can be considered that sacrificing a small amount of coil efficiency in the incomplete compensation scheme is acceptable.

[0136] Table 2. Coil Parameters

[0137]

[0138] Furthermore, parameter design under strongly coupled mode:

[0139] To address situations with large coupling coefficients, an additional static impedance matching network is employed to match the already determined Z-axis. coil The impedance trajectory (designed in weakly coupled mode) is transformed into a reasonable Z-axis. T Then connect it to a Class E power amplifier. At this time:

[0140] Z PA =Z T (12)

[0141] In the simplified dual-modal compensation topology, the matching network consists of an inductor X T1 and a capacitor X T3 Composition, can be omitted Figure 1 X of the resonant compensation network T2 The remaining two design degrees of freedom in the matching network (inductance X) T1 and capacitor X T3 ) can be used to determine Z T Maximum coupling load point Z T,max The location is designed to maximize the coupling load point Z. T,max Minimum Coupled Load Point Z in Weakly Coupled Mode coil,min The overlap ensures that the Class E power amplifiers at the two boundary points of the target region have the same operating state; it also makes full use of the target region. Due to the universality of impedance parameter design, the coupling coefficient decreases from maximum coupling, Z... T The extended impedance trajectory will be automatically included within the target region. Furthermore, the difference in coil efficiency between the two can be further considered, allowing the specified Z... T,max For smaller power levels, we will not go into details here.

[0142] The following relationship exists for resonant compensation networks:

[0143]

[0144] In the formula Z coil,max This represents the overall input impedance of the maximum coupling coil;

[0145] If the minimum coupled load point coincides with the maximum coupled load point, that is:

[0146] Z T,max =Z coil,min (14)

[0147] Obtain the parameters of the resonant compensation network:

[0148]

[0149]

[0150] In the formula X coil,max The overall input impedance Z of the maximum coupled coil coil,max The reactance component, R coil,max The overall input impedance Z of the maximum coupled coil coil,max The resistive component.

[0151] Specific Implementation Method Three: Combination Figure 1 , Figure 2 and Figure 5 As shown, this embodiment provides a dual-mode compensation topology circuit with strong anti-migration characteristics. It is designed based on the dual-mode compensation topology circuit with strong anti-migration characteristics described in Specific Embodiment 1. The dual-mode compensation topology circuit with strong anti-migration characteristics described in Specific Embodiment 1 includes a Class E power amplifier, a resonant compensation network, a coupling coil, and a rectifier.

[0152] The input of a Class E power amplifier is connected to a power supply V. dc The output of the Class E power amplifier is connected to the input of the resonant compensation network, the output of the resonant compensation network is connected to the primary input of the coupling coil, and the secondary output of the coupling coil is connected to the input of the rectifier.

[0153] Class E power amplifiers include inductors L f Switch Q, capacitor Cs, capacitor C0, inductor L0, power supply V dc The positive terminal is connected to the inductor L f One end, inductor L f The other end is connected to the drain of the switching transistor Q, and the source of the switching transistor Q is connected to the power supply V. dc The negative terminal of the capacitor is grounded; the capacitor Cs is connected in parallel with the switch Q, the drain of the switch Q is connected to one end of the capacitor C0, and the other end of the capacitor C0 is connected to one end of the inductor L0.

[0154] The resonant compensation network includes inductor X T1 Reactance X T2 and capacitor X T3 Inductor X T1 One end corresponds to the other end of inductor L0, and inductor X T1The other end is connected to reactor X T2 One end, reactance X T2 The other end serves as an output terminal of the resonant compensation network, capacitor X T3 One end is connected to inductor X T1 and reactance X T2 Between, capacitance X T3 The other end serves as the other output of the resonant compensation network;

[0155] Replace inductors L0 and X with a combined inductor consisting of inductors L1 and L2. T1 Reactance X T2 Set to 0;

[0156] In weak coupling mode, the center tap of the inductor is connected to one primary input terminal of the coupling coil, short-circuiting inductor L2 and capacitor X. T3 Disconnect from the circuit; in strong coupling mode, unshort-circuit inductor L2 and capacitor X. T3 Connect to the circuit.

[0157] As described in Specific Implementation Methods 1 and 2, the weakly coupled mode and the strongly coupled mode respectively employ incomplete coil compensation and resonant compensation networks for impedance matching of the Class E power amplifier. The switching between the two modes is achieved by relay switching of the impedance compression network. In traditional three-element resonant compensation network designs, at least two relays are required to achieve switching. In this implementation method, X... T2 The unnecessary component is omitted, allowing the switching between weakly coupled and strongly coupled modes to be achieved with just a single-pole double-throw relay. The final circuit of the dual-mode compensation topology is as follows: Figure 5 As shown, the combined inductance of L1 and L2 is used to equivalently replace the output inductance L0 of the power amplifier and the inductance X of the resonant compensation network. T1 This further improves power density. The center tap of the inductor is connected to one contact port of the relay. In weakly coupled mode, L2 is short-circuited by the relay, X T3 Removed; in strongly coupled mode, L1 and L2 in the circuit are connected in series, X T3 Access.

[0158] Detailed Implementation Method Four: Combination Figures 5 to 7 As shown, this embodiment provides a parameter design method for a dual-mode compensation topology circuit with strong anti-offset characteristics. The method designs the parameters of the dual-mode compensation topology circuit with strong anti-offset characteristics described in Embodiment 3. This embodiment is based on the parameter design process of Embodiment 2, and designs the parameters of inductors L1 and L2. The entire design process includes:

[0159] Equivalent load is applied to the Class E power amplifier;

[0160] The effect of the rectifier on the Class E power amplifier can be equivalently expressed as the fundamental input impedance Z. rec :

[0161] Z rec =R rec +jX rec (1)

[0162] In the formula R rec X is the equivalent resistance component of the rectifier. rec This is the equivalent reactance component of the rectifier;

[0163] The self-inductance of the coupling coil and the transmitting coil is L. tx The self-inductance of the coupling coil receiving coil is L. rx L rx The capacitor C connected in series with it rx If the reactance component of the secondary side of the coupling coil is compensated together, then the total reactance compensation amount X on the secondary side is... rx for:

[0164]

[0165] In the formula, ω is the angular frequency;

[0166] Then the total input impedance Z on the secondary side RX for:

[0167] Z RX =R rec +r rx +j(X rec +X rx (3)

[0168] In the formula r rx The resistance of the receiving coil;

[0169] In the equivalent circuit model of a loosely coupled voltage transformer composed of coupled coils, the effect of the secondary side on the primary side is represented by the reflection impedance Z connected in series with the transmitting coil. ref Equivalent to:

[0170] Z ref =R ref +jX ref (4)

[0171] In the formula R ref The reflection impedance Z ref The resistive component, X ref The reflection impedance Z ref Reactance component:

[0172]

[0173]

[0174] In the formula, M is the mutual inductance of the loosely coupled voltage transformer;

[0175] Similar to the receiving coil, the self-inductance L of the coupling coil and the transmitting coil is... tx The capacitor C connected in series with it tx Together they are considered as the total primary reactance compensation amount X tx :

[0176]

[0177] Then the overall input impedance Z of the coupled coil is obtained. coil :

[0178] Z coil =Z ref +jX tx +r rx (8)

[0179] Furthermore, parameter design in the weakly coupled mode:

[0180] Based on the parameters of the Class E power amplifier, the amplifier load impedance Z PA Simulation parameter scanning yields contour lines for amplifier output power and efficiency; the amplifier load impedance Z is then determined from these contour lines. PA The target region corresponding to the design objective, wherein the varying amplifier load impedance Z PA Maintain stable output power in the target area;

[0181] Make the overall input impedance Z of the coupling coil coil If the trajectory is within the target area, then:

[0182] Z PA =Z coil (9)

[0183] The overall input impedance Z of the coupled coil coil Incomplete compensation will be provided.

[0184] The minimum mutual inductance M under the condition of minimum coupling between the transmitting coil and the receiving coil min The corresponding minimum coupled coil overall input impedance Z coil,min Set at one edge of the target area to make the target area encompass a wider range of variations in the mutual inductance M of the loosely coupled voltage transformers, based on the minimum mutual inductance M. min and the overall input impedance Z of the minimum coupled coil coil,min The total secondary reactance compensation amount X is calculated. rx Total reactance compensation amount X tx .

[0185] In this embodiment, the total secondary reactance compensation amount Xrx Total reactance compensation amount X tx The calculation method is as follows:

[0186]

[0187]

[0188] In the formula R coil.min The overall input impedance Z of the minimum coupled coil coil,min The resistive component, X coil.min The overall input impedance Z of the minimum coupled coil coil,min The reactive component;

[0189] Z coil,min =R coil.min +jX coil.min .

[0190] Furthermore, parameter design under strongly coupled mode:

[0191] Make the overall input impedance Z of the coupling coil coil Converted to impedance Z T ,but:

[0192] Z PA =Z T (12)

[0193] From inductor X T1 and capacitor X T3 Determine the impedance Z T Maximum coupling load point Z T,max The position of the point Z with maximum coupling load. T,max Overall input impedance Z of the minimum coupled coil coil,min The overlap ensures that the Class E power amplifiers at the two boundary points of the target region have the same operating state;

[0194] For resonant compensation networks:

[0195]

[0196] In the formula Z coil,max This represents the overall input impedance of the maximum coupling coil;

[0197] By: Z T,max =Z coil,min (14)

[0198] Obtain the parameters of the resonant compensation network:

[0199]

[0200]

[0201] In the formula X coil,max The overall input impedance Z of the maximum coupled coil coil,max The reactance component, R coil,max The overall input impedance Z of the maximum coupled coil coil,max The resistive component.

[0202] Based on this, in the strongly coupled mode, inductors L1 and L2 are coupled, and the combined inductance is equal to L0 and X. T1 In series, then:

[0203] L0+X T1 =L1+L2+2M 12 (17)

[0204] In the formula M 12 The mutual inductance of inductors L1 and L2;

[0205] In the weakly coupled mode, R L1 As the parasitic resistance of inductor L1, R L2 As the parasitic resistance of inductor L2, we obtain the following equations:

[0206]

[0207] In the formula, U is the voltage across the inductor;

[0208] In practical applications, the quality factor of the coil is relatively large, so the parasitic resistance R is omitted. L1 and parasitic resistance R L2 According to the equivalent circuit of the inductor in the weakly coupled mode, such as Figure 6 As shown, the equivalent value of the inductance at this time is L0, resulting in:

[0209]

[0210] In the formula I in The input current is the combined inductor. Figure 6 Middle I in1 I is the input current of inductor L2. in2 This represents the short-circuit branch current.

[0211] The values ​​of inductance L1 and inductance L2 are calculated using formulas (17) and (19).

[0212] In summary, the general design steps for a dual-modal compensation topology can be summarized as follows: Figure 7 As shown. First, design reasonable Class E power amplifier circuit parameters to obtain the target load range. Then, determine the rectifier input impedance Z. rec Next, according to Figure 1 The impedance transformation sequence from right to left is designed sequentially for Z. coilZ T By coordinating the maximum mutual inductance M max This ensures that the impedance trajectories of both components, varying with mutual inductance, fully occupy the target region, thereby expanding the range of coupling coefficient variation. Finally, the parameters of the coil self-inductance, compensation capacitance, and aggregate inductance in the equivalent circuit are determined.

[0213] Simulation Experiment: The parameter design of this invention can achieve stable output state of the system under two mode combinations. To verify the rationality of the design, a megahertz wireless power transmission system based on a dual-mode compensation topology was built in the simulation. The main system parameters are shown in Table 3. A commonly used full-wave rectifier was selected for the rectifier section. In addition, actual diode and switching transistor models were imported into the simulation to improve consistency with the actual situation. The target region of the Class E power amplifier is relatively fixed, and the impedance trajectory and matching network parameters have a certain degree of universality. Therefore, for mutual inductance varying within a certain range, the design can always achieve similar results. The design process follows the above design steps, and the parameters of the resonant compensation network are listed in Table 4. The final load impedance trajectories of the power amplifiers in the two modes are shown in Table 4. Figure 7 As shown.

[0214] Table 3 System Parameters

[0215]

[0216] Table 4 Resonance Compensation Network Parameters

[0217]

[0218] Figure 9 , Figure 10 Simulation results for the overall system efficiency and input voltage under constant output voltage are presented. The range of the coupling coefficient from 0.2 to 0.25 in the figure represents the candidate interval for the switching point. Within this interval, the input voltage is at a reasonable level in weak coupling mode, but the system efficiency decreases as the coupling coefficient increases. In strong coupling mode, the system efficiency is at a reasonable level, but the input voltage required to maintain a constant output voltage increases sharply as the coupling coefficient decreases. Figure 9 and Figure 10 In the selection area, the switch position between the two modes is marked with an arrow. Figure 9 The solid line represents the system efficiency when switching from a weakly coupled mode to a strongly coupled mode. Figure 10The solid line represents the input voltage at which the system switches from strongly coupled to weakly coupled mode. The selection of the switching point allows for overlap in the coupling coefficient ranges of the two modes, which can be mitigated by using hysteresis design to eliminate system noise or jitter. To achieve stable voltage gain and efficient inverter operation, the following switching logic can be summarized: when the input voltage required to achieve the target output voltage is detected to be too high in strongly coupled mode, the system will switch to weakly coupled mode; when a decrease in system efficiency is detected in weakly coupled mode, the system will switch back to strongly coupled mode. Specific implementation examples:

[0220] The switching function of the dual-mode impedance matching network is key to this invention, and its feasibility needs to be verified experimentally. Based on the parameters of the simulation circuit described above, a prototype of a megahertz wireless power transfer system was built. In addition to the basic components of megahertz wireless power transfer, such as a Class E power amplifier, coupling coil, and Class E full-wave rectifier, the experimental platform also features pre-amplifier voltage regulation, voltage and current sampling, and primary-secondary communication. This ensures a closed-loop output, meaning the output voltage remains constant despite changes in the coupling coefficient. Compared to a single resonant compensation network scheme, the primary-side circuit of the prototype only adds one relay, thanks to a reasonable parameter design and the introduction of a three-pin tapped inductor in the prototype.

[0221] Ultimately, the choice of switching point depends on the actual performance of the system. Figure 11 and Figure 12 Experimental results show the system input voltage and efficiency as a function of the coupling coefficient. Compared with the simulation results, the system efficiency decreases at some points, which may be due to factors that the simulation cannot account for, such as PCB board losses, coil eddy current losses, and additional magnetic field coupling. However, the experimental results generally fit the simulation curve well; when the coupling coefficient k changes from 0.107 to 0.385, the input voltage changes by less than 10V. Meanwhile, the system efficiency reaches a maximum of 88.5%, and even at the lowest coupling coefficient of 0.107, it still achieves 80.2%.

[0222] Figure 13 and Figure 14 This demonstrates the source voltage (V) of the Class E power amplifier switching transistor before and after the switching point k=0.227 from weak to strong coupling. GS ) and drain-source voltage (V DS The waveform shows that a more ideal soft-switching effect was achieved after the switch, which improved the efficiency of the inverter section.

[0223] Figure 15 and Figure 16 The waveforms of the input and output voltages are shown when the relative positions of the coils are changed and the mode is switched, with the triggering time always in the middle position. Figure 16In the case of strong coupling mode, reducing the coupling coefficient causes the input voltage to exceed the switching threshold. After switching to weak coupling mode, the input voltage is reduced to a reasonable level through closed-loop regulation.

[0224] In summary, the performance of the dual-mode compensation topology with strong anti-migration capability, based on the system parameter design method proposed in this invention, has been verified. This invention adds only one relay with almost no additional cost, and the system's stability is guaranteed within a given range of coupling coefficient variation. Experiments show that the system with the dual-mode compensation topology has an input voltage variation range of less than 10V, a maximum overall system efficiency of 88.5%, and achieves 80.2% even at the lowest coupling coefficient. This compensation topology has broad application prospects in the design of megahertz wireless power transfer anti-migration systems.

[0225] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A dual-mode compensation topology circuit with strong anti-offset characteristics, characterized in that... This includes a Class E power amplifier, a resonant compensation network, coupling coils, and a rectifier. The input of a Class E power amplifier is connected to a power supply V. dc The output of the Class E power amplifier is connected to the input of the resonant compensation network, the output of the resonant compensation network is connected to the primary input of the coupling coil, and the secondary output of the coupling coil is connected to the input of the rectifier. Class E power amplifiers include inductors L f Switch Q, capacitor Cs, capacitor C0, inductor L0, power supply V dc The positive terminal is connected to the inductor L f One end, inductor L f The other end is connected to the drain of the switching transistor Q, and the source of the switching transistor Q is connected to the power supply V. dc The negative terminal of the capacitor is grounded; the capacitor Cs is connected in parallel with the switch Q, the drain of the switch Q is connected to one end of the capacitor C0, and the other end of the capacitor C0 is connected to one end of the inductor L0. The resonant compensation network includes inductor X T1 Reactance X T2 and capacitor X T3 Inductor X T1 One end corresponds to the other end of inductor L0, and inductor X T1 The other end is connected to reactor X T2 One end, reactance X T2 The other end serves as an output terminal of the resonant compensation network, capacitor X T3 One end is connected to inductor X T1 and reactance X T2 Between, capacitance X T3 The other end serves as the other output of the resonant compensation network; In weak coupling mode, the other end of inductor L0 replaces one output of the resonant compensation network and is connected to one primary input of the coupling coil. In strong coupling mode, make inductor X T1 One end is connected to the other end of inductor L0, and the reactance X T2 The other end is connected to one primary input terminal of the coupling coil; simultaneously, the reactance X T2 The value is 0.

2. The dual-mode compensation topology circuit with strong anti-offset characteristics according to claim 1, characterized in that, Switching between weakly coupled and strongly coupled modes is achieved using a single-pole double-throw relay.

3. A method for designing parameters of a dual-mode compensation topology circuit with strong anti-migration characteristics, comprising designing parameters of the dual-mode compensation topology circuit with strong anti-migration characteristics as described in claim 1 or 2, characterized in that... This includes equivalent loads for Class E power amplifiers; The effect of the rectifier on the Class E power amplifier can be equivalently expressed as the fundamental input impedance Z. rec : ，（1） In the formula R rec X is the equivalent resistance component of the rectifier. rec This is the equivalent reactance component of the rectifier; The self-inductance of the coupling coil and the transmitting coil is L. tx The self-inductance of the coupling coil receiving coil is L. rx L rx The capacitor C connected in series with it rx If the reactance component of the secondary side of the coupling coil is compensated together, then the total reactance compensation amount X on the secondary side is... rx for: ，（2） In the formula Angular frequency; Then the total input impedance Z on the secondary side RX for: ，（3） In the formula The resistance of the receiving coil; In the equivalent circuit model of a loosely coupled voltage transformer composed of coupled coils, the effect of the secondary side on the primary side is represented by the reflection impedance Z connected in series with the transmitting coil. ref Equivalent to: ，（4） In the formula R ref The reflection impedance Z ref The resistive component, X ref The reflection impedance Z ref Reactance component: ，（5） ，（6） In the formula Mutual inductance for loosely coupled voltage converters; Similar to the receiving coil, the self-inductance L of the coupling coil and the transmitting coil is... tx The capacitor C connected in series with it tx Together they are considered as the total primary reactance compensation amount X tx : ，（7） Then the overall input impedance Z of the coupled coil is obtained. coil : （8）。 4. The method for designing parameters of a dual-mode compensated topology circuit with strong anti-offset characteristics according to claim 3, characterized in that, Parameter design in a loosely coupled mode: Based on the parameters of the Class E power amplifier, the amplifier load impedance Z PA Simulation parameter scanning yields contour lines for amplifier output power and efficiency; the amplifier load impedance Z is then determined from these contour lines. PA The target region corresponding to the design objective, wherein the varying amplifier load impedance Z PA Maintain stable output power in the target area; Make the overall input impedance Z of the coupling coil coil If the trajectory is within the target area, then: ，（9） The overall input impedance Z of the coupled coil coil Incomplete compensation will be provided. The minimum mutual inductance M under the condition of minimum coupling between the transmitting coil and the receiving coil min The corresponding minimum coupled coil overall input impedance Z coil,min Set at one edge of the target area to allow the target area to include a wider range of loosely coupled voltage transformer inductances. The range of variation, based on the minimum mutual inductance M min and the overall input impedance Z of the minimum coupled coil coil,min The total secondary reactance compensation amount X is calculated. rx Total reactance compensation amount X tx .

5. The method for designing parameters of a dual-mode compensated topology circuit with strong anti-offset characteristics according to claim 4, characterized in that, Secondary side total reactance compensation X rx Total reactance compensation amount X tx The calculation method is as follows: ，（10） ，（11） In the formula The overall input impedance Z of the minimum coupled coil coil,min The resistive component, The overall input impedance Z of the minimum coupled coil coil,min The reactive component; 。 6. The method for designing parameters of a dual-mode compensated topology circuit with strong anti-offset characteristics according to claim 5, characterized in that, Parameter design in a strongly coupled mode: Make the overall input impedance Z of the coupling coil coil Converted to impedance Z T ,but: ，（12） From inductor X T1 and capacitor X T3 Determine the impedance Z T Maximum coupling load point Z T,max The position of the point Z with maximum coupling load. T,max Overall input impedance Z of the minimum coupled coil coil,min The overlap ensures that the Class E power amplifiers at the two boundary points of the target region have the same operating state; For resonant compensation networks: ，（13） In the formula This represents the overall input impedance of the maximum coupling coil; Depend on: (14) Obtain the parameters of the resonant compensation network: ，（15） ，（16） In the formula The overall input impedance of the maximum coupled coil The reactance component, The overall input impedance of the maximum coupled coil The resistive component.

7. A dual-mode compensation topology circuit with strong anti-offset characteristics, characterized in that, Based on the dual-mode compensation topology circuit with strong anti-offset characteristics described in claim 1, inductors L0 and X are replaced by a combined inductor composed of inductors L1 and L2. T1 Reactance X T2 Set to 0; In weak coupling mode, the center tap of the inductor is connected to one primary input terminal of the coupling coil, short-circuiting inductor L2 and capacitor X. T3 Disconnect from the circuit; in strong coupling mode, unshort-circuit inductor L2 and capacitor X. T3 Connect to the circuit.

8. The dual-mode compensation topology circuit with strong anti-offset characteristics according to claim 7, characterized in that, Switching between weakly coupled and strongly coupled modes is achieved using a single-pole double-throw relay.

9. A method for designing parameters of a dual-mode compensation topology circuit with strong anti-migration characteristics, comprising designing parameters of the dual-mode compensation topology circuit with strong anti-migration characteristics as described in claim 7 or 8, characterized in that, Based on the dual-mode compensation topology circuit parameter design method with strong anti-offset characteristics described in claims 3 to 6, the parameters of inductor L1 and inductor L2 are further designed: In strong coupling mode, inductors L1 and L2 are coupled, and the combined inductance is equal to L0 and X. T1 In series, then: ，（17） In the formula The mutual inductance of inductors L1 and L2; In the weakly coupled mode, R L1 As the parasitic resistance of inductor L1, R L2 As the parasitic resistance of inductor L2, we obtain the following equations: ，（18） In the formula The voltage across the inductor; Parasitic resistance R omitted L1 and parasitic resistance R L2 Based on the equivalent circuit of the inductor in the weakly coupled mode, we obtain: ，（19） In the formula The input current is the combined inductor. The values ​​of inductance L1 and inductance L2 are calculated according to formulas (17) and (19).

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