Three-dimensional wireless power transmission system based on multi-frequency magnetic field space orientation

Abstract

The present application relates to a three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation, which introduces multi-frequency technology to expand the number of charging targets. The system applies a multi-frequency modulation method based on H-bridge inverter, which can provide two different frequency voltages to the circuit of the transmitting coil, and the output voltage of each frequency component can be controlled by the duty cycle of the corresponding bridge arm switch. The system uses a multi-frequency resonant network to filter the inverter output voltage, and the two fundamental components corresponding to the switching frequency are retained, so that the multi-frequency superimposed current is obtained in the transmitting coil. In this system, the three superimposed currents in the orthogonal transmitting coil group can synthesize two magnetic field vectors of different frequencies, and the two magnetic field vectors can be oriented to different positions in space respectively. When multiple receivers enter the working space of the system, independent power supply can be obtained. The present application expands the function of the three-dimensional wireless power transmission system for directional charging of multiple moving targets, and can be applied to mobile device charging of multiple users, robot charging of logistics factories, unmanned aerial vehicle charging of field operations and other working occasions.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless power transmission, and in particular relates to a three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation. Background Art

[0002] With the development of materials science, power electronics, power conversion, and control technologies, wireless power transmission systems have broad application prospects in electric vehicles, aerospace, power systems, renewable energy generation, medical equipment, lighting, portable communications, and other fields. Electromagnetic coupling resonant wireless power transmission technology is a cutting-edge topic in the field of power transmission and a brand-new technological field. It utilizes the principle of magnetic coupling resonance to generate a high-frequency alternating coupling magnetic field through two coils with the same resonant frequency to achieve power transmission over a certain distance. Compared to traditional wiring-based power transmission technology, this technology is more flexible, safe, and reliable, capable of short- and medium-range power transmission between power supply equipment and power-consuming equipment, and has the advantages of strong versatility and high safety.

[0003] Three-dimensional (3D) wireless power transfer (WPT) systems are particularly useful in specialized applications due to their high spatial freedom. However, as the number of mobile receivers increases, traditional 3D WPT systems struggle to simultaneously meet the charging needs of these devices. Therefore, it is necessary to develop novel 3D WPT systems capable of providing directional energy transfer to multiple mobile loads. Summary of the Invention

[0004] To address the aforementioned technical issues, the present invention provides a novel three-dimensional wireless power transmission system based on multi-frequency technology, which introduces multi-frequency technology to expand the number of charging targets. A multi-frequency modulation method based on an H-bridge inverter is applied to provide two voltages of different frequencies to the transmitter coil circuit. The output voltage of each frequency component is controlled by the switching duty cycle of its corresponding bridge arm. The system uses a multi-frequency resonant network to filter the inverter output voltage, preserving the two fundamental components corresponding to the switching frequency, and obtaining a multi-frequency superimposed current in the transmitting coil. In this system, the three superimposed currents in the orthogonal transmitting coil group can synthesize two magnetic field vectors of different frequencies, and the two magnetic field vectors can be oriented to different locations in space. When multiple receivers enter the system's operating space, they can each receive independent power supply.

[0005] A three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation, the method comprising the following steps:

[0006] S1, designed a multi-frequency modulation method based on H-bridge inverter, which outputs voltages containing two different frequency components simultaneously through a single H-bridge;

[0007] S2, a multi-frequency resonant network topology was designed to filter the inverter output voltage. This resonant network has two different passband frequencies, which can retain two fundamental currents of different frequencies and obtain a superimposed current of multi-frequency mixing in the transmitting coil;

[0008] S3, based on the amplitude and phase control of multi-frequency currents in three transmitting coils, designed a spatial magnetic field orientation method that can simultaneously locate two different directions in space, realizing the multi-load directional energy transmission function of the multi-frequency three-dimensional wireless power transmission system.

[0009] As a further improvement of the present invention, the multi-frequency modulation method based on the H-bridge inverter in step S1 has the following specific process:

[0010] The multi-frequency modulation method based on the H-bridge inverter system consists of three mutually perpendicular transmitting coils, each transmitting coil is controlled by a separate inverter, and all inverters are connected in parallel to a DC voltage source u dc superior, and m=1,2 is the output voltage of the inverter, which stimulates current in coils A, B and C respectively. and The two receivers Rx1 and Rx2 are placed at different locations in the working space, and the resonant capacitor C s1 、C s2 and loads 1 and 2 are connected in series with Rx1 and Rx2 respectively;

[0011] In the multi-frequency modulation method based on the H-bridge inverter, the switching frequency of the system is f m , the left bridge arm of the inverter operates at frequency f1, while the right bridge arm operates at frequency f2, and the output voltage of each frequency component is controlled by the duty cycle of the bridge arm switch.

[0012] In the circuit of the transmitting coil A, S1, S2, S3 and S4 are driving signals for the MOSFETs in the H-bridge inverter. S1 and S2 are complementary, as are S3 and S4. S1 and S2 as well as S3 and S4 operate at different frequencies. The circuits of coils B and C are the same as above.

[0013] As a further improvement of the present invention, the multi-frequency resonant network topology structure of step S2 is specifically as follows. The multi-frequency resonant network of the multi-frequency resonant network topology structure has two bandpass frequencies. The multi-frequency resonant network is used to filter the inverter output voltage to obtain a superimposed current containing two frequency components. The specific process is as follows:

[0014] Each transmitting coil of the three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation is connected to a multi-frequency resonant network composed of a series capacitor and a parallel LC branch. The multi-frequency resonant network has two resonance points, providing two frequency channels for energy transmission;

[0015] The multi-frequency resonant network in the circuit of the transmitting coil A includes a series LC branch, and includes the coil A and a parallel LC branch. Through parameter design, the network exhibits series resonance characteristics at frequencies f1 and f2. The corresponding parameter conditions are as follows:

[0016]

[0017] Where ω1 and ω2 are the angular frequencies of f1 and f2 respectively;

[0018] Output voltage and After passing through the multi-frequency resonant network, since the multi-frequency resonant network has two passbands, two sinusoidal currents corresponding to the switching frequency are retained. Based on the above method, two currents of different frequencies with controllable amplitude and phase are obtained in the transmitting coil;

[0019] Output voltage and After passing through the multi-frequency resonant network, since the multi-frequency resonant network has two passbands, two sinusoidal currents corresponding to the switching frequency are retained. The circuits of coils B and C are the same as above.

[0020] As a further improvement of the present invention, in step S3, the amplitudes and phases of the multi-frequency currents in the three transmitting coils are independently adjusted and controlled through multi-frequency modulation, and the three currents of each frequency are synthesized into a spatially directional magnetic field vector, thereby achieving directional energy transmission of multiple loads in space. The specific process is as follows:

[0021] Since the direction of the synthetic magnetic vector is determined by the amplitude and phase of the coil current, the multi-frequency current in the transmitting coil can generate two synthetic magnetic vectors for locating different targets;

[0022] In this system, all transmitting coil currents have two frequency components, the magnetic vector and By current and Produced, and the magnetic vector and By current and F1 and F2 are the magnitudes of the resultant magnetic vectors, θ1 and θ2 are the azimuths in the spatial coordinate system, and is the elevation angle. By using a dedicated controller, the load position orientation can be conveniently achieved by adjusting the transmitting coil current to its reference value. The set value of the coil current can be calculated by the following formula

[0023]

[0024]

[0025] in

[0026]

[0027]

[0028] I base1 and I base2 is a positive real number related to the amplitudes of F1 and F2;

[0029] The circuit equation of the multi-frequency three-dimensional wireless power transmission system converted into a circuit model is as follows

[0030]

[0031] in

[0032] ω1 and ω2 are the corresponding angular frequencies of f1 and f2;

[0033] Receivers 1 and 2 resonate at f1 and f2 respectively, and the resonance equation of the system is expressed as

[0034]

[0035] If the resonant frequencies of the receiver and transmitter are different, the receiver current will have almost no effect on the transmitter coil current. On this basis, the receiver current is calculated from the equation listed above:

[0036]

[0037] in

[0038]

[0039] As shown in equation (7), these azimuth angles θ1 and θ2 and the elevation angle are adjusted and The value of can maximize the load current. Physically, it is explained that the position of the load is oriented by the net magnetic vector. The mathematical expression of the prerequisite for magnetic field orientation is:

[0040]

[0041] Since the values ​​of these azimuth and elevation angles are adjusted by coil current control, the multi-frequency three-dimensional wireless power transfer system simultaneously positions two receivers.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] This paper proposes a novel three-dimensional wireless power transmission system that incorporates multi-frequency technology to expand the number of charging targets. In this system, a multi-frequency modulation method based on an H-bridge inverter is used to provide two voltages of different frequencies to the transmitter coil circuit. The output voltage of each frequency component is controlled by the switching duty cycle of the corresponding bridge arm. A multi-frequency resonant network is used to filter the inverter output voltage, preserving the two fundamental components corresponding to the switching frequency, resulting in a multi-frequency superimposed current in the transmitter coil. In this system, the three superimposed currents in the orthogonal transmitting coil group can synthesize two magnetic field vectors of different frequencies, each of which can be directed to different locations in space. When multiple receivers enter the system's operating space, they can each receive independent power. This system extends the capability of directional charging for multiple moving targets and is suitable for applications such as charging multi-user mobile devices, charging robots in logistics factories, and charging drones for field operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The overall structure of a three-dimensional wireless power transmission system based on multi-frequency technology;

[0045] Figure 2 Schematic diagram of magnetic vector direction in multi-frequency three-dimensional wireless power transmission system;

[0046] Figure 3 Inverter circuit principles and key waveforms of multi-frequency modulation;

[0047] Figure 4 Circuit model of multi-frequency three-dimensional wireless power transmission system;

[0048] Figure 5 Multi-frequency three-dimensional wireless power transmission system parameter design process;

[0049] Figure 6 Experimental prototype of a multi-frequency three-dimensional wireless power transfer system;

[0050] Figure 7 Key waveforms of the multi-frequency modulation method: (a) when the system operates at 80kHz; (b) when the system operates at 200kHz; (c) when the system operates in multi-frequency modulation;

[0051] Figure 8Directional experimental results: (a) Transmitting coil current in case 1; (b) Experimental demonstration of LED load in case 1; (c) Transmitting coil current in case 2; (d) Experimental demonstration of LED load in case 2. DETAILED DESCRIPTION

[0052] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0053] This invention proposes a multi-frequency, three-dimensional wireless power transmission system for multi-load directional transmission. Multi-frequency modulation based on an H-bridge inverter generates multi-frequency drive voltages, while a multi-frequency resonant network preserves the fundamental components of each frequency. This combination enables controllable amplitude and phase characteristics of the transmitted current across two frequency channels. Two independently controllable currents in three coils combine to form two spatially directional magnetic field vectors, enabling directional energy transmission to multiple loads.

[0054] This patent provides a design method for a new three-dimensional wireless power transmission system based on multi-frequency technology. The specific steps are as follows:

[0055] 1) A multi-frequency modulation method based on an H-bridge inverter is designed, which can simultaneously output voltages containing two different frequency components through a single H-bridge.

[0056] The system proposed in the present invention consists of three mutually perpendicular transmitter coils, each transmitter coil is controlled by a separate inverter, and all inverters are connected in parallel to a DC voltage source u dc Above, such as Figure 1 shown. and is the output voltage of the inverter, which can stimulate current in coils A, B and C respectively and The two receivers Rx1 and Rx2 are placed at different locations in the working space, and the resonant capacitor C s1 、C s2 And loads 1 and 2 are connected in series with Rx1 and Rx2 respectively.

[0057] The system proposed in this paper adopts a new modulation method. In this modulation method, the switching frequency of the system is f m The left bridge arm of the inverter operates at frequency f1, while the right bridge arm operates at frequency f2. The output voltage of each frequency component can be controlled by the duty cycle of the bridge arm switch, such as Figure 3 As shown. Take the circuit of transmitting coil A as an example to illustrate the working principle of multi-frequency modulation. Figure 3 In (a) and (b), S1, S2, S3, and S4 are the drive signals for the MOSFETs in the H-bridge inverter. S1 and S2 are complementary, as are S3 and S4. However, they operate at different frequencies. Figure 3(c) is the voltage The output voltage and coil current of the inverter when acting alone, Figure 3 (d) is the voltage The results when acting alone, Figure 3 (e) is the voltage and current waveform under multi-frequency modulation.

[0058] 2) A multi-frequency resonant network topology was designed for filtering the inverter output voltage. This resonant network has two different passband frequencies, which can retain two fundamental currents of different frequencies and obtain a superimposed current of multi-frequency mixing.

[0059] like Figure 1 As shown, each transmitting coil in the system is connected to a multi-frequency resonant network consisting of a series capacitor and a parallel LC branch. The multi-frequency resonant network has two resonant points, providing two frequency channels for energy transmission. Taking the circuit of coil A as an example: its multi-frequency resonant network includes a series LC branch (including coil A) and a parallel LC branch. Through parameter design, the network can exhibit series resonance characteristics at frequencies f1 and f2. The corresponding parameter conditions are as follows:

[0060]

[0061] where ω1 and ω2 are the angular frequencies of f1 and f2 respectively.

[0062] Output voltage and After passing through the multi-frequency resonant network, the two sinusoidal currents corresponding to the switching frequency are retained because the multi-frequency resonant network has two passbands. Based on the above method, two currents of different frequencies with controllable amplitude and phase can be obtained in the transmitting coil.

[0063] 3) Based on the amplitude and phase control of the multi-frequency currents in the three transmitting coils, a spatial magnetic field orientation method is designed that can simultaneously locate two different directions in space, realizing the multi-load directional energy transmission function of the multi-frequency three-dimensional wireless power transmission system.

[0064] Since the direction of the synthetic magnetic vector is determined by the amplitude and phase of the coil current, the multi-frequency current in the transmitting coil can generate two synthetic magnetic vectors for locating different targets, such as Figure 2 shown.

[0065] In this system, all transmit coil currents have two frequency components. Figure 2 In the magnetic vector and By current and Produced, and the magnetic vector and By current and F1 and F2 are the magnitudes of the resultant magnetic vectors, θ1 and θ2 are the azimuths in the spatial coordinate system, and is the elevation angle. By using a dedicated controller, the load position orientation can be conveniently achieved by adjusting the transmitting coil current to its reference value. The set value of the coil current can be calculated by the following formula

[0066]

[0067]

[0068] in

[0069]

[0070]

[0071] I base1 and I base2 is a positive real number related to the amplitudes of F1 and F2.

[0072] In order to gain a deeper understanding of the proposed multi-frequency three-dimensional wireless power transmission system, Figure 1 The system shown is converted into a circuit model as Figure 4 shown.

[0073] Depend on Figure 4 The circuit model in the system can be obtained as follows:

[0074]

[0075] in

[0076] and ω2 are the corresponding angular frequencies of f1 and f2.

[0077] Receivers 1 and 2 resonate at f1 and f2 respectively. The resonance equation of the system can be expressed as

[0078]

[0079] If the resonant frequencies of the receiver and transmitter are different, the receiver current will have almost no effect on the transmitter coil current. Based on this, the receiver current can be calculated from the equation listed above

[0080]

[0081] in

[0082]

[0083] As shown in equation (7), these azimuth angles θ1 and θ2 and the elevation angle are adjusted and The value of can maximize the load current. Physically speaking, the position of the load is oriented by the net magnetic vector. The mathematical expression of the prerequisite for magnetic field orientation is:

[0084]

[0085] Since the values ​​of these azimuth and elevation angles can be adjusted by coil current control, the multi-frequency three-dimensional wireless power transfer system can simultaneously locate two receivers.

[0086] like Figure 6 As shown in the figure, the present invention designs and constructs a complete 20W multi-frequency three-dimensional wireless power transmission system. In actual system design, the operating frequencies ω1 and ω2 of the system are generally pre-set based on commercial or national standards. And the self-inductance of the coil is determined by the structure of the coil, so ω1, ω2, and L A ,L B ,L C ,L s1 ,L s2 The value of is considered as a known quantity. The other parameters in the system can be solved by equation (4). Take the circuit of coil A as an example. For simplicity, L a The value of is solved by the following formula:

[0087] L a =λL A (8)

[0088] Detailed parameter design process is as follows Figure 5 The multi-frequency modulation scheme is implemented on a digital signal processor (DSP, TMS32028335) and is executed by three independent H-bridges. The inverter consists of four MOSFETs (JCS50N20WT). The system operates at 80kHz and 200kHz. A 12V DC voltage source provides power to the system. The resonant network consists of a custom-made inductor and several film capacitors. The ferrite core used in the inductor is RM14. The detailed parameters of the prototype are shown in Table 1.

[0089] Table 1

[0090] Detailed parameters of three-dimensional wireless power transmission system based on multi-frequency technology

[0091]

[0092] 1) Multi-frequency modulation experimental verification

[0093] The multi-frequency modulation verification experiment results are as follows Figure 7As shown in the figure, the waveforms from top to bottom are the drive signals of S1 and S3, the output voltage of the inverter and the emission current. Figure 3 The experimental results are in good agreement with the theoretical analysis. The slight differences in the waveforms are mainly caused by parameter offsets.

[0094] 2) Multi-load directional experimental verification

[0095] In order to verify the correctness of the multi-load orientation theory, we first define the direction of the magnetic vector in the space coordinate as a three-dimensional vector. Figure 1 As shown, if coil A is Excited, the magnetic vector along the X axis is "1", if the coil B is ("-"express and The phase difference between them is π, the phase is set as the reference), and the magnetic vector along the Y axis is "-1". In this way, the direction of the magnetic vector in the eight quadrants of the spatial coordinate can be defined as: (1,1,1) (m) ,(-1,1,1) (m) ,(-1,-1,1) (m) ,(1,-1,1) (m) ,(1,1,-1) (m) ,(-1,1,-1) (m) ,(-1,-1,-1) (m) ,(1,-1,-1) (m) The superscript m is used to distinguish whether the frequency of the oriented magnetic vector is f1 or f2. Another point to note is that the magnetic vector generated in the spatial coordinates will pass through two quadrants symmetrical about the origin. In this experiment, an LED load is used to demonstrate the results of magnetic field orientation. The experimental results are shown in Figure 2. Figure 8 shown.

[0096] Figure 8 (a) and (c) show the transmitting coil current in two cases. Figure 8 In (b) and (d), these LED lights demonstrate the effect of directional power transmission. Figure 8 In (a) and (b), the magnetic vector is concentrated at (1,-1,1) (1) and (1,1,-1) (2) The receivers in the fourth and sixth quadrants can be powered by a magnetic field with a frequency of f1, and the receivers in the third and fifth quadrants can be powered by a magnetic field with a frequency of f2. Figure 8 In (c) and (d), the direction of the magnetic vector is (1,-1,1) (1) and (1,-1,-1) (2) , the magnetic field is focused in the second, fourth, sixth and eighth quadrants. From the position of the LED, it can be seen that the experimental results are in good agreement with the theoretical analysis.

[0097] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any modification or equivalent variation based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A control method for a three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation, characterized in that: The control method comprises the following steps: S1, designed a multi-frequency modulation method based on H-bridge inverter, which outputs voltages containing two different frequency components simultaneously through a single H-bridge; S2, a multi-frequency resonant network topology is designed for filtering the inverter output voltage. The resonant network has two different passband frequencies, thereby retaining two fundamental currents of different frequencies and obtaining a multi-frequency mixed superposition current on the transmitting coil. Each transmitting coil is connected to a multi-frequency resonant network consisting of a series capacitor and a parallel LC branch. S3, based on the amplitude and phase control of the multi-frequency currents in the three transmitting coils, a spatial magnetic field orientation method was designed that can simultaneously locate two different directions in space, realizing the multi-load directional energy transmission function of the multi-frequency three-dimensional wireless power transmission system. In this method, the three currents of each frequency are synthesized into a spatially directional magnetic field vector, thereby realizing the directional energy transmission of multiple loads in space, as shown in the following formula: Among them, the mth frequency f m The three currents are and I basem is a positive real number, and the magnitude of the resultant magnetic vector F m related; Azimuth angle θ in the spatial coordinate system m ∈[0,π], elevation angle in the spatial coordinate system 2. The control method of a three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation according to claim 1, characterized in that: The multi-frequency modulation method based on the H-bridge inverter in step S1 is specifically described as follows: The multi-frequency modulation method based on the H-bridge inverter system consists of three mutually perpendicular transmitting coils, each transmitting coil is controlled by a separate inverter, and all inverters are connected in parallel to a DC voltage source u dc superior, and m=1,2 is the output voltage of the inverter, which stimulates current in coils A, B and C respectively. and The two receivers Rx1 and Rx2 are placed at different locations in the working space, and the resonant capacitor C s1 、C s2 and loads 1 and 2 are connected in series with Rx1 and Rx2 respectively; In the multi-frequency modulation method based on the H-bridge inverter, the switching frequency of the system is f m , the left bridge arm of the inverter operates at frequency f1, while the right bridge arm operates at frequency f2, and the output voltage of each frequency component is controlled by the duty cycle of the bridge arm switch; In the circuit of the transmitting coil A, S1, S2, S3 and S4 are the driving signals of the MOSFETs in the H-bridge inverter. S1 and S2 are complementary, as are S3 and S4. S1 and S2 as well as S3 and S4 operate at different frequencies. The circuits of coils B and C are the same as above.

3. The control method of a three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation according to claim 1, characterized in that: The multi-frequency resonant network topology structure of step S2 is specifically as follows. The multi-frequency resonant network of the multi-frequency resonant network topology structure has two bandpass frequencies. The multi-frequency resonant network is used to filter the inverter output voltage to obtain a superimposed current containing two frequency components. The specific process is as follows: The multi-frequency resonant network has two resonance points, providing two frequency channels for energy transmission; The multi-frequency resonant network in the circuit of the transmitting coil A includes a series LC branch, and includes the coil A and a parallel LC branch. Through parameter design, the network exhibits series resonance characteristics at frequencies f1 and f2. The corresponding parameter conditions are as follows: Where ω1 and ω2 are the angular frequencies of f1 and f2 respectively; Output voltage and After passing through the multi-frequency resonant network, since the multi-frequency resonant network has two passbands, two sinusoidal currents corresponding to the switching frequency are retained. Based on the above method, two currents of different frequencies with controllable amplitude and phase are obtained in the transmitting coil; Output voltage and After passing through the multi-frequency resonant network, since the multi-frequency resonant network has two passbands, two sinusoidal currents corresponding to the switching frequency are retained. The circuits of coils B and C are the same as above.

4. The control method of a three-dimensional wireless power transmission system based on multi-frequency magnetic field spatial orientation according to claim 1, characterized in that: In step S3, the amplitudes and phases of the multi-frequency currents in the three transmitting coils are independently adjusted and controlled through multi-frequency modulation, and the three currents of each frequency are synthesized into a spatially directional magnetic field vector, thereby achieving directional energy transmission of multiple loads in space. The specific process is as follows: Since the direction of the synthetic magnetic vector is determined by the amplitude and phase of the coil current, the multi-frequency current in the transmitting coil can generate two synthetic magnetic vectors for locating different targets; In this system, all transmitting coil currents have two frequency components, the magnetic vector and By current and Produced, and the magnetic vector and By current and F1 and F2 are the magnitudes of the resultant magnetic vectors, θ1 and θ2 are the azimuths in the spatial coordinate system, and is the elevation angle. By using a dedicated controller, the load position orientation can be conveniently achieved by adjusting the transmitting coil current to its reference value. The set value of the coil current can be calculated by the following formula in I base1 and I base2 is a positive real number related to the amplitudes of F1 and F2; The circuit equation of the multi-frequency three-dimensional wireless power transmission system converted into a circuit model is as follows in ω1 and ω2 are the angular frequencies of f1 and f2 respectively; and m=1,2 is the output voltage of the inverter; Receivers 1 and 2 resonate at f1 and f2 respectively, and the resonance equation of the system is expressed as If the resonant frequencies of the receiver and transmitter are different, the receiver current will have almost no effect on the transmitter coil current. On this basis, the receiver current is calculated from the equation listed above: in As shown in equation (7), these azimuth angles θ1 and θ2 and the elevation angle are adjusted and The value of can maximize the load current. Physically, it is explained that the position of the load is oriented by the net magnetic vector. The mathematical expression of the prerequisite for magnetic field orientation is: Since the values ​​of these azimuth and elevation angles are adjusted by coil current control, the multi-frequency three-dimensional wireless power transfer system simultaneously positions two receivers.

Images