Wireless receiving circuit and dynamic wireless power supply device

Abstract

The present invention is applicable to the field of wireless power supply technology, and provides a wireless receiving circuit and a dynamic wireless power supply device, wherein the wireless receiving circuit comprises: two receiving units; the receiving unit comprises a receiving coil and a compensating inductor, the receiving coil is used for mutual inductance with the transmitting coil, the receiving coil and the compensating inductor are connected in series, the two ends of the series circuit serve as the output ends of the receiving unit, and the output ends of the two receiving units are used to be connected in parallel to the same external load; wherein the magnitude of the compensating inductors of the two receiving units is determined by the inductive reactance of the two receiving coils, and is configured to make the current phasors in the two receiving units conjugate complex and mutually orthogonal. The present invention can achieve stable output of charging power during dynamic movement of electric vehicles.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless power supply, and in particular relates to a wireless receiving circuit and a dynamic wireless power supply device. Background Art

[0002] With the rapid development of new energy vehicles in my country in recent years and the introduction of corresponding government car purchase subsidy policies, more and more families are choosing electric vehicles as their means of transportation.

[0003] According to media reports, the battery life problem of electric vehicles has not yet been fully solved. Most household electric cars need to rely on long-term charging piles. The power cord of the charging pile will be frequently plugged and unplugged, which is not only prone to mechanical wear, but also poses a safety hazard. The number of electric vehicle charging stations put into operation in the city is insufficient, and the charging interface standards of different models of cars are not completely unified. This not only makes it difficult for electric vehicle users to charge, but also leads to the idleness of some special interface charging piles with a small audience, indirectly causing a waste of resources. In special occasions (such as near oil refineries and chemical plants, low-lying areas and areas with serious rodent infestations), the traditional contact power supply method also has safety hazards such as arc discharge of electrical interfaces, flooding of equipment, and damage to line insulation. The traditional expansion method of installing large-capacity rechargeable battery packs on cars that often travel long distances has space, load restrictions and economic budget issues.

[0004] Wireless power supply technology is a new type of power transmission method in which a power source supplies power to a load without electrical contact through a high-frequency magnetic field or electric field. The application of wireless power supply technology in various fields has unparalleled advantages over traditional contact power supply. Especially in my country's automobile manufacturing industry, which ranks among the top in the world in terms of production and ownership, the market demand for new energy vehicles will continue to increase in the future, considering the limitations of traditional fossil energy reserves. Because there is no need to be limited by the capacity of the battery pack, the load capacity and cruising range of electric vehicles based on dynamic wireless power supply will be greatly improved. In the field of electric vehicles, the dynamic wireless power supply system is mainly composed of a DC bus buried under the road surface, a high-frequency inverter, a compensation device and a power transmission coil, as well as a vehicle-mounted receiving coil, a compensation device, a high-frequency rectifier and an energy storage battery. The purpose is to achieve charging while driving based on wireless power supply. Its long-term goal is to build a renewable energy highway. With the help of power transmission coils buried every few meters, photovoltaic and wind power generation devices installed on the roadside can be used nearby to power electric vehicles on the road. With the continuous development of the concept of dynamic wireless power supply for electric vehicles, the stability of dynamic power supply has attracted more and more attention from electric vehicle users.

[0005] In order to avoid unnecessary line loss and magnetic leakage of the primary transmitting coil and improve the energy transmission efficiency, the primary side of the dynamic wireless power supply system of electric vehicles generally adopts segmented coils. When working, it is based on the active request excitation of the secondary vehicle receiving coil and the primary receiving end positioning device and decentralized control technology to achieve regional precise power supply. As an important part of the electromagnetic induction coupling wireless power transmission mechanism, the electromagnetic coupling mechanism has structural parameters that directly determine the stability of the primary and secondary coils during dynamic operation. However, in the segmented area, the mutual inductance between the primary transmitting coil and the secondary receiving coil will inevitably fluctuate, which will directly affect the stability of the charging power of the electric vehicle. Summary of the invention

[0006] In view of this, an embodiment of the present invention provides a wireless receiving circuit and a dynamic wireless power supply device to achieve stable output of charging power during dynamic movement of an electric vehicle.

[0007] A first aspect of an embodiment of the present invention provides a wireless receiving circuit, including:

[0008] Two receiving units;

[0009] The receiving unit includes a receiving coil and a compensating inductor, the receiving coil is used for mutual inductance with the transmitting coil, the receiving coil and the compensating inductor are connected in series, the two ends of the series circuit serve as output ends of the receiving unit, and the output ends of the two receiving units are used for parallel connection to the same external load;

[0010] The magnitude of the compensation inductance of the two receiving units is determined by the inductive reactance of the two receiving coils, and is configured to make the current phasors in the two receiving units conjugate complex numbers and orthogonal to each other.

[0011] Optionally, the wireless receiving circuit further includes:

[0012] Rectification unit;

[0013] The output end of the receiving unit includes a first output end and a second output end, the first output ends of the two receiving units are both connected to the first input end of the rectifying unit, and the second output ends of the two receiving units are both connected to the second input end of the rectifying unit;

[0014] The first output terminal and the second output terminal of the rectifier unit are used to connect two ends of the same external load.

[0015] Optionally, a filter capacitor is further connected between the first output terminal and the second output terminal of the rectifier unit.

[0016] A second aspect of an embodiment of the present invention provides a dynamic wireless power supply device, comprising: a wireless transmitting circuit and a wireless receiving circuit as described in the first aspect above;

[0017] The wireless transmitting circuit includes a plurality of transmitting units, each of which includes a transmitting coil, and the transmitting coil is used for mutual inductance with two receiving coils in the wireless receiving circuit.

[0018] Optionally, the wireless transmission circuit further includes:

[0019] DC power supply and inverter unit;

[0020] Each transmitting unit also includes a matching capacitor, which is connected in series with the transmitting coil. The two ends of the series line serve as input ends of the transmitting unit. The input end of each transmitting unit is connected to the output end of the inverter unit, and the input end of the inverter unit is connected to the output end of the DC power supply.

[0021] Optionally, the receiving coils in the two receiving units are both solenoid coils, and the two receiving units are arranged side by side.

[0022] Optionally, the transmitting coils in each transmitting unit are solenoid coils, and the transmitting units are arranged in sequence.

[0023] Optionally, the inverter unit in the wireless transmitting circuit is a full-bridge inverter, and the rectifier unit in the wireless receiving circuit is a full-bridge rectifier.

[0024] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0025] The embodiment of the present invention adopts an orthogonal decoupling dual-coil structure, so that the mutual inductance between the two receiving coils and the transmitting coil changes according to the sine and cosine laws respectively, and then uses the wireless receiving circuit to configure the impedance parameters so that the synthesized output current is stably output, that is, a group of receiving units with the same topology and different impedance parameters are connected in parallel at both ends of the equivalent load resistor, so that the current phasors of the two receiving units are conjugate complex numbers and are orthogonal to each other, ensuring that the modulus value of the two current phasors is a constant after superposition, and at the same time, the phase angle of the phasor changes within a fixed range, thereby realizing the stable output of charging power during the dynamic movement of the electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 is a schematic structural diagram of a wireless receiving circuit provided by an embodiment of the present invention;

[0028] Figure 2 is a secondary side receiving current vector diagram provided by an embodiment of the present invention;

[0029] Figure 3 is a schematic diagram of the variation range of the load current vector provided by an embodiment of the present invention;

[0030] Figure 4 is a schematic structural diagram of a wireless receiving circuit provided by an embodiment of the present invention;

[0031] Figure 5 It is a schematic diagram of the structure of a dynamic wireless power supply device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0033] In order to illustrate the technical solution of the present invention, a specific embodiment is provided below for illustration.

[0034] Traditional dynamic wireless power supply systems achieve stable power transmission through closed-loop control or design of coupling mechanisms. Closed-loop control has high requirements for control accuracy and response speed, and the complex design of the coupling mechanism will increase costs. Therefore, this embodiment adopts an orthogonal decoupling dual-coil structure so that the mutual inductance between the two receiving coils and the transmitting coil changes according to the sine and cosine laws respectively, and then uses the wireless receiving circuit to configure the impedance parameters so that the synthesized output current is output stably. It can simplify the system without complex control strategies, and reduce the difficulty of coupling mechanism design and reduce costs.

[0035] See also Figure 1 As shown, this embodiment provides a wireless receiving circuit, including:

[0036] Two receiving units S1 and S2.

[0037] The receiving unit (taking S1 as an example) includes a receiving coil L S1 and a compensation inductor C S1 , receiving coil L S1 For use with the transmitting coil L P Mutual inductance, receiving coil L S1 and compensation inductor C S1The two ends of the series circuit are used as the output ends of the receiving unit. The output ends of the two receiving units S1 and S2 are used to be connected in parallel to the same external load. The size of the compensation inductance of the two receiving units is determined by the inductive reactance of the two receiving coils, and is configured to make the current phasors in the two receiving units conjugate complex and orthogonal to each other.

[0038] In the embodiment of the present invention, the variation rule of mutual inductance in the dynamic process can be expressed by the following formula:

[0039] M PS1 =Msinθ

[0040] That is, during the continuous offset cycle of the receiving coil, the mutual inductance curve between the coupling coils is approximately a sine function with the distance. Since the power is positively correlated with the square of the mutual inductance, when the secondary receiving coil moves, the mutual inductance waveform of the original secondary coupling coil is approximately a sine function.

[0041] In order to achieve the purpose of constant power output, two coils orthogonal to the primary side mutual inductance waveform can be arranged on the secondary side, and the trigonometric function identity M PS1 2 sin 2 θ+M PS2 2 cos 2 θ=M 2 Based on the principle, the wireless dynamic charging topology of electric vehicles is improved. That is, a group of secondary networks with the same topology and different impedance parameters are connected in parallel at both ends of the equivalent load resistor, so that the mesh current phasors of the two secondary sides are conjugate complex and orthogonal to each other, which can ensure that the modulus of the two current phasors is constant after superposition, and the phase angle δ of the phasor changes between -45° and 45°. The superposition of the two mesh current phasors is a phasor with a constant amplitude and a phase angle changing within a fixed range.

[0042] Specifically, for Figure 1 The circuit coupling model of the electromagnetic resonant wireless power supply system shown in the figure has a secondary mesh that satisfies Kirchhoff's voltage law:

[0043]

[0044] From this, the secondary current can be deduced as:

[0045]

[0046] set up but:

[0047]

[0048]

[0049] Where, let the impedance angle of mesh 2 be k=ω / Z, we get:

[0050]

[0051] At this time, the charging load equivalent resistance R L The power obtained is:

[0052]

[0053] Considering that if the current flowing through the load equivalent resistance is a complex number, unnecessary reactive current components will be generated, reducing the efficiency of power transmission, the two mesh current phasors can be made symmetrical about the real axis, which can minimize the reactive component of the current flowing through the load after the two meshes are superimposed. When the amplitudes of the two mesh currents on the secondary side are equal, the current phase angle δ flowing through the load is equal to 0°, which is a pure real number, such as Figure 2 By adjusting the compensation inductor C S1 , C S2 , the current phasor angles of the two meshes on the secondary side can be made symmetrical about the real axis:

[0054]

[0055] Since the mutual inductance waveforms of the two receiving coils on the secondary side and the primary side differ by 90° in the rotating coordinate system, the following approximation can be made:

[0056] M PS1 =Msinθ

[0057] M PS2 =Mcosθ

[0058] Considering that the current modulus flowing through the load equivalent resistance and the current modulus of the two meshes on the secondary side should satisfy the Pythagorean theorem, the current phasor angles of the two meshes should be complementary:

[0059] φ-(-φ)=90°φ=45°

[0060] The current flowing through the load equivalent resistance is for:

[0061]

[0062] The phase angle δ is taken as Figure 3 As shown:

[0063] That is, the charging load equivalent resistance R L The power obtained is:

[0064]

[0065] It can be seen that its complex power only contains the real part, and is only related to the amplitude of the mutual inductance waveform between the coupled coils, and has nothing to do with the instantaneous value of the mutual inductance of the primary and secondary coils. Therefore, the embodiment of the present invention adopts an orthogonal decoupling dual coil structure, so that the mutual inductance between the receiving coil and the transmitting coil changes according to the sine and cosine laws respectively, and then uses the wireless receiving circuit to configure the impedance parameters so that the synthesized output current is output stably, that is, a group of receiving units with the same topology and different impedance parameters are connected in parallel at both ends of the equivalent load resistor, so that the current phasors of the two receiving units are conjugate complex numbers and mutually orthogonal, ensuring that the modulus value of the two current phasors is constant after superposition, and the phase angle δ of the phasor changes within a fixed range of -45° to 45°. When the secondary receiving coil is directly above the primary transmitting coil or at any position, the sum of the squares of the current flowing through the load equivalent resistor remains unchanged, thereby achieving a stable output of charging power during the dynamic movement of the electric vehicle.

[0066] As a possible implementation, see Figure 4 As shown, the wireless receiving circuit also includes:

[0067] Rectification unit.

[0068] The output ends of the receiving units S1 and S2 each include a first output end and a second output end. The first output ends of the two receiving units are connected to the first input end of the rectifier unit (the midpoint of D1 and D3), and the second output ends of the two receiving units are connected to the second input end of the rectifier unit (the midpoint of D2 and D4). The first output end and the second output end of the rectifier unit are used to connect to the same external load R L both ends of .

[0069] As a possible implementation, see Figure 4 As shown, a filter capacitor C is also connected between the first output terminal and the second output terminal of the rectifier unit. L .

[0070] An embodiment of the present invention provides a dynamic wireless power supply device, see Figure 5 As shown, the dynamic wireless power supply device includes a wireless transmitting circuit and a wireless receiving circuit as described above. The wireless transmitting circuit includes a plurality of transmitting units ( Figure 5 Only one transmitting unit is used as an example), each transmitting unit includes a transmitting coil L P , transmitting coil L P Used to perform mutual inductance with two receiving coils in a wireless receiving circuit.

[0071] As a possible implementation, the wireless transmitting circuit further includes:

[0072] DC power supply U and inverter unit.

[0073] Each transmitting unit also includes a matching capacitor CP , matching capacitor C P With the transmitting coil L P The two ends of the series line are used as input ends of the transmitting unit, the input end of each transmitting unit is connected to the output end of the inverter unit, and the input end of the inverter unit is connected to the output end of the DC power supply U.

[0074] In this embodiment, the transmitting unit adopts a solenoid coil structure, which is connected to the inverter unit and the DC power supply and provides electrical energy. The receiving unit corresponds to the transmitting unit and is connected to the rectifier unit. The dual receiving coil structure of the orthogonal solenoid and the Q coil can be used to achieve decoupling, and ensure that the mutual inductance between the two receiving coils and the transmitting coil changes in an approximately sine and cosine law during dynamic operation, and stable output is achieved by configuring the impedance of the wireless receiving circuit. The inverter unit is connected to the DC power supply U and the transmitting unit, and is used to convert a constant DC voltage into a high-frequency AC voltage with adjustable pulse width. The rectifier unit is connected to the receiving unit and the load R L (such as a car battery) to rectify high-frequency AC current into a stable DC current.

[0075] As a possible implementation, the inverter unit in the wireless transmission circuit is as follows Figure 5 The full-bridge inverter shown in FIG. 1 and the rectifier unit in the wireless receiving circuit are as follows: Figure 5 The full bridge rectifier is shown.

[0076] As a possible implementation method, the receiving coil and the transmitting coil can both be solenoid coils, the two receiving units are arranged side by side, and the transmitting units are arranged in sequence, specifically, they can be arranged in sequence along the road direction to achieve stable output of charging power during the movement of the car.

[0077] This embodiment realizes orthogonal superposition of secondary currents by configuring the impedances of two secondary loops, so that the output current can achieve a constant output independent of the position, and realizes the stability of dynamic power supply without control, thereby reducing the difficulty of coupling mechanism design, reducing costs, and effectively solving the problems of low coupling coefficient, low power transmission power and transmission efficiency, and large leakage magnetic field in the prior art.

[0078] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A wireless receiving circuit, characterized in that: include: Two receiving units; Each of the receiving units includes a receiving coil and a compensating inductor, the receiving coil is used for mutual inductance with the transmitting coil, the receiving coil and the compensating inductor are connected in series, the two ends of the series circuit serve as the output ends of the receiving unit, and the output ends of the two receiving units are used for parallel connection to the same external load; The magnitude of the compensation inductance of the two receiving units is determined by the inductive reactance of the two receiving coils, and is configured to make the current phasors in the two receiving units conjugate complex numbers and orthogonal to each other; The wireless receiving circuit further includes: a rectifying unit; The output end of the receiving unit includes a first output end and a second output end, the first output ends of the two receiving units are connected to the first input end of the rectifying unit, and the second output ends of the two receiving units are connected to the second input end of the rectifying unit; The first output terminal and the second output terminal of the rectifier unit are used to connect two ends of the same external load; A filter capacitor is also connected between the first output end and the second output end of the rectifier unit; The receiving coils in the two receiving units are both solenoid coils, and the two receiving units are arranged side by side.

2. A dynamic wireless power supply device, characterized in that: include: A wireless transmitting circuit and a wireless receiving circuit as claimed in claim 1; The wireless transmitting circuit includes a plurality of transmitting units, each of which includes a transmitting coil, and the transmitting coil is used for mutual induction with two receiving coils in the wireless receiving circuit.

3. The dynamic wireless power supply device according to claim 2, characterized in that: The wireless transmission circuit also includes: DC power supply and inverter unit; Each transmitting unit also includes a matching capacitor, which is connected in series with the transmitting coil. The two ends of the series line serve as input ends of the transmitting unit. The input end of each transmitting unit is connected to the output end of the inverter unit, and the input end of the inverter unit is connected to the output end of the DC power supply.

4. The dynamic wireless power supply device according to claim 2, characterized in that: The transmitting coils in each transmitting unit are solenoid coils, and the transmitting units are arranged in sequence.

5. The dynamic wireless power supply device according to claim 2, characterized in that: The inverter unit in the wireless transmitting circuit is a full-bridge inverter, and the rectifier unit in the wireless receiving circuit is a full-bridge rectifier.

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