Complementary coupling system applied to dynamic wireless power transmission

Abstract

The invention provides a complementary coupling system applied to dynamic wireless power transmission, which comprises a segmented direct current bus for supplying direct current obtained after a power frequency power grid is rectified to an inversion-control module of a corresponding road section, and the inversion-control module inverts the direct current into high-frequency alternating current; the inverted high-frequency alternating current completes resonance with the primary multi-pole transmitting coil or the primary single-pole transmitting coil through the primary compensation network, transmits energy to the integrated receiving coil based on a near-field resonance coupling principle, and completes resonance with the integrated receiving coil through the secondary compensation network; the high-frequency alternating current is converted into stable direct current through the rectifying and filtering module and is output to a vehicle battery; wherein the multi-pole type transmitting coil and the single-pole type transmitting coil which are located on the primary side are alternately laid, and the integrated receiving coil is formed by connecting and overlapping a multi-pole type receiving coil and a single-pole type receiving coil in series. According to the invention, the advantages of the single-pole coil and the multi-pole coil are utilized, so that stable and efficient dynamic wireless power transmission can be achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of wireless power transmission, and in particular, relates to a complementary coupling system applied to dynamic wireless power transmission. Background Art

[0002] Due to the convenience and speed of wireless charging, more and more power-consuming devices are adopting wireless charging, and dynamic wireless power transmission (DWPT) can realize charging while walking.

[0003] Existing dynamic wireless charging devices can be divided into two categories: long rails and segmented rails. Considering electromagnetic interference and charging efficiency, the current method of laying out the transmitting coils in segmented arrays is mostly adopted. However, in the existing coil coupling system, when the transmitting coils are laid out at a close distance, there will be cross-coupling between adjacent coils, which increases the complexity of the dynamic wireless charging system analysis and the uncertainty of the system transmission characteristics; when the laying distance is far, it will significantly cause the DC output voltage or current of the system receiving end to fluctuate too much, thereby affecting the charging quality and causing damage to the battery.

[0004] Therefore, efficient decoupling of the transmitting coil cannot be achieved, which greatly increases the difficulty of designing dynamic wireless charging compensation parameters and easily leads to resonance point offset, thereby reducing energy transfer efficiency. Summary of the invention

[0005] In view of this, the present application aims to propose a complementary coupling system for dynamic wireless power transmission to solve the problems of mutual inductance cross-coupling between multiple power transmitting coils in the dynamic wireless power transmission system and power zero point and power fluctuation at the receiving end during the movement of the power receiving body.

[0006] To achieve the above purpose, the technical solution of this application is implemented as follows:

[0007] The present application provides a complementary coupling system for dynamic wireless power transmission, including a segmented DC bus, an inverter-control module, a compensation network, a multi-pole transmitting coil, a monopole transmitting coil, an integrated receiving coil and a rectifier filter module;

[0008] The segmented DC bus supplies the DC power obtained after rectification of the industrial frequency power grid to the inverter-control module of the corresponding section, and the inverter-control module inverts the DC power into high-frequency AC power. The inverted high-frequency AC power resonates with the multi-pole transmitting coil or the monopole transmitting coil of the primary side through the compensation network of the primary side, transfers energy to the integrated receiving coil based on the near-field resonant coupling principle, resonates with the integrated receiving coil through the compensation network of the secondary side, and then converts the high-frequency AC power into stable DC power through the rectification and filtering module and outputs it to the vehicle battery;

[0009] The multipolar transmitting coil and the monopolar transmitting coil located on the primary side are alternately laid, and the integrated receiving coil is formed by superimposing a multipolar receiving coil and a monopolar receiving coil in series.

[0010] Furthermore, the DC power in the segmented DC bus is obtained by rectifying the 50Hz / 380V industrial frequency power grid through an electric energy converter, and the segmented DC bus power distribution is used to supply power to multiple wireless power supply segments in time and segment.

[0011] Furthermore, the monopole transmitting coil and the monopole receiving coil are composed of a single coil structure, and the current generated on the coil flows in a single direction, forming a relatively concentrated magnetic field region with a consistent direction.

[0012] Furthermore, the multipolar transmitting coil and the multipolar receiving coil are composed of a plurality of coils, and the number of magnetic poles is 2k (k=1, 2, . . . ), so as to generate magnetic fields in two directions and form a uniform and wide magnetic field area.

[0013] Furthermore, the coil shape adopts a square structure or a circular structure.

[0014] Further, the compensation network includes a primary side LCC compensation network and a secondary side LCC compensation network;

[0015] The primary LCC compensation network includes a primary compensation inductor and a primary compensation capacitor, and the secondary LCC compensation network includes a secondary compensation inductor and a secondary compensation capacitor; wherein both ends of the primary transmitting coil and the secondary transmitting coil are respectively connected to the common side endpoints of the primary and secondary compensation capacitors.

[0016] Furthermore, the relationship between the output power and input power of the LCC resonant compensation network under the lossless model is expressed as:

[0017]

[0018] Where U in is the input voltage, I f2 is the secondary resonant current, L f1 and L f2 are the primary compensation inductor and the secondary compensation inductor respectively, M is the mutual inductance between the primary and secondary coils, R L is the equivalent load.

[0019] Compared with the prior art, the complementary coupling system for dynamic wireless power transmission described in this application has the following beneficial effects:

[0020] The present application describes a complementary coupling system for dynamic wireless power transmission. The system utilizes the different characteristics of unipolar coils and multipolar coils to overcome the cross-coupling problem between primary coils without adding additional compensation devices, greatly simplifying the difficulty of designing compensation parameters. It adopts an integrated coupling compensation strategy between a receiving coil and different types of transmitting coils. It only requires simple adjustment of the number of coil turns to make the mutual inductance smooth and stable, thereby making the output power smooth and stable, which is of great significance to further improving the dynamic wireless power transmission technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0022] Figure 1 A schematic diagram of a complementary coupling system for dynamic wireless power transmission according to an embodiment of the present application;

[0023] Figure 2 This is a schematic diagram of a monopolar coil according to an embodiment of the present application;

[0024] Figure 3 This is a schematic diagram of a multi-pole coil according to an embodiment of the present application;

[0025] Figure 4 This is a complementary waveform diagram of the mutual inductance during the freezing process of the power receiving body described in the embodiment of the present application;

[0026] Figure 5 This is an equivalent circuit diagram of the bilateral LCC topology described in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0028] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0029] See also Figure 1 As shown, this embodiment provides a complementary coupling system for dynamic wireless power transmission, including a segmented DC bus, an inverter-control module, a compensation network, a multi-pole transmitting coil, a monopole transmitting coil, an integrated receiving coil and a rectifier filter module;

[0030] The segmented DC bus supplies the DC power obtained after rectification of the industrial frequency power grid to the inverter-control module of the corresponding section. The inverter-control module inverts the DC power into high-frequency AC power. The inverted high-frequency AC power resonates with the multi-pole transmitting coil or the monopole transmitting coil of the primary side through the compensation network of the primary side, and transfers energy to the integrated receiving coil based on the near-field resonant coupling principle. The secondary side compensation network resonates with the integrated receiving coil, and then the high-frequency AC power is converted into stable DC power through the rectification and filtering module and output to the vehicle battery.

[0031] Among them, the multipolar transmitting coil and the monopolar transmitting coil located on the primary side are laid alternately, and the integrated receiving coil is formed by superimposing the multipolar receiving coil and the monopolar receiving coil in series.

[0032] Specifically, in this embodiment, the dynamic wireless power transmission system uses an alternating magnetic field as a medium for energy transfer between the receiving and transmitting coils, and starts and stops the transmitting coil at the corresponding position in real time according to the position of the mobile power receiver. The segmented DC bus supplies the DC power obtained after rectification of the industrial frequency power grid to the inverter-control module of the corresponding section. The inverter-control module inverts the DC power into high-frequency AC power, generates a high-frequency electromagnetic field in space, and controls the start and stop of the corresponding transmitting coil at the same time. The inverted high-frequency AC power resonates with the multi-polar transmitting coil or unipolar transmitting coil of the primary side through the compensation network of the primary side, and transfers energy to the integrated receiving coil based on the principle of near-field resonant coupling, and resonates with the integrated receiving coil through the compensation network of the secondary side. Finally, the high-frequency AC power is converted into stable DC power through the rectification and filtering module and output to the battery.

[0033] The system can provide efficient power transmission for dynamic wireless charging devices; at the same time, during the movement of the mobile power receiver, it can overcome the power zero point phenomenon and power fluctuation phenomenon that occur at its receiving end, and there is no need to consider the influence of cross-inductance between the power transmitting coils. It can provide stable and reliable power supply guarantee for the mobile power receiver and has broad market prospects.

[0034] The transmitting end of the system does not require additional compensation devices to reduce the impact of cross-coupling between power transmitting coils, which reduces costs and simplifies the design of compensation parameters. The receiving end uses a superposition design of two different types of coils to achieve complementary coupling between different types of coils, greatly improving the transmission performance. The system has the advantages of both unipolar coils and multi-polar coils, and can achieve smooth, reliable and efficient dynamic wireless power transmission.

[0035] Furthermore, in the present application, the DC power in the segmented DC bus is obtained by rectifying the 50Hz / 380V industrial frequency power grid through an electric energy converter. The use of segmented DC bus power distribution can realize time-sharing and segmented power supply for the required wireless power supply segments, reduce guide rail losses and electromagnetic radiation, and is simpler and easier to implement than the AC bus power supply structure, with higher overall efficiency.

[0036] The inverter-control module includes a full-bridge inverter circuit and a circuit control unit with STM32 as the main control chip. The full-bridge inverter circuit consists of four switching devices (MOSFET) and works according to a specific switching sequence to convert direct current into high-frequency alternating current. At the same time, the high-frequency alternating current generates a high-frequency alternating magnetic field and transfers energy through a coupling mechanism. The circuit control unit is responsible for starting and stopping the transmitting coil on the primary side in real time according to the changes in the moving position of the receiving body, so as to improve the utilization rate of electric energy and reduce electromagnetic interference.

[0037] The compensation network is divided into the primary side LCC compensation network and the secondary side LCC compensation network;

[0038] The primary LCC compensation network includes the primary compensation inductor L f1 And the primary compensation capacitor C f1 , C p ; The secondary side LCC compensation network includes the secondary side compensation inductor L f2 and the secondary compensation capacitor C f2 , C s ; Among them, the primary transmitting coil L p and the secondary transmitting coil L s The two ends are respectively connected to the common side endpoints of the two compensation capacitors on the primary and secondary sides.

[0039] The coupling mechanism is the core device of the complementary coupling system of dynamic wireless power transmission, including a primary transmitting coil and a secondary receiving coil, wherein the primary transmitting coil includes a multi-pole transmitting coil and a monopole transmitting coil, which are alternately laid.

[0040] like Figure 2 As shown, the monopolar coil consists of a single coil structure. The current flows in a single direction on the coil, which can form a relatively concentrated magnetic field with consistent direction. The monopolar coil has only one main magnetic pole, and the generated magnetic field is mainly concentrated in one direction.

[0041] like Figure 3 As shown, the multipolar coil is composed of multiple coil units, with at least two magnetic poles, and can generate magnetic fields in two directions to form a more uniform and extensive magnetic field area. When placed on the same horizontal plane as the monopolar coil according to the laying requirements, the magnetic flux flowing into the monopolar coil generated by the multipolar coil is equal to the magnetic flux flowing out of it, and the magnetic flux flowing in and out of the two cancel each other out. In theory, the mutual inductance between the two different types of coils is zero, which can achieve the effect of decoupling between the transmitting coils. The coil shape can be a square structure or a circular structure.

[0042] The secondary receiving coil is an integrated receiving coil, which is composed of the multipolar coil and the unipolar coil connected in series and superimposed, and the overall size is the same as the transmitting coil. Due to the particularity of the structure, when the unipolar receiving coil and the symmetrical multipolar transmitting coil are facing each other, the magnetic flux flowing into the coil and the magnetic flux flowing out of the coil cancel each other, and the mutual inductance of the receiving and transmitting coils is close to zero, and vice versa; when the same-polarity receiving and transmitting coils are facing each other, the magnetic fields between the two are mutually enhanced, and the mutual inductance is almost the maximum value at this time. The continuous fluctuation of the mutual inductance will lead to the existence of zero transmission power and violent power fluctuations during the operation of the system.

[0043] When the receiving coil adopts an integrated structure of two different types of coils connected in series, when the receiving coil moves along the transmitting rail, the peaks and troughs of the mutual inductance values ​​between the two groups of different types of coils can be compensated for each other, and the mutual inductance fluctuations will be smoother and more stable after superposition.

[0044] The complementary waveform of the mutual inductance during the movement of the power receiving body in this application is as follows Figure 4 As shown, the multipolar coil and the monopolar coil of the primary transmitting coil are laid alternately, waveform M1 is a schematic diagram of the change of the mutual inductance waveform when the receiving coil has only the multipolar coil, and waveform M2 is a schematic diagram of the change of the mutual inductance waveform when the receiving coil has only the monopolar coil. When the receiving coil is an integrated coil after the two are superimposed in series, the mutual inductance between the receiving coil and the transmitting coil during the movement is the sum of the two waveforms, that is, waveform MSUM. At this time, the mutual inductance waveform achieves a smooth and stable effect.

[0045] like Figure 5 As shown in the bilateral LCC topology equivalent circuit diagram, U in is the input voltage, U0 is the output voltage, I f1 and I f2 is the primary-secondary resonant current, I p is the primary coil current, I s is the secondary coil current, L f1 and L f2 They are the primary compensation inductor and the secondary compensation inductor, C f1 and C p is the primary compensation capacitor, C f2 and C s is the secondary compensation capacitor, L p and L s are the self-inductance of the primary coil and the self-inductance of the secondary coil, M is the mutual inductance between the primary and secondary coils, R L is the equivalent load. Analyze the circuit in the figure and use Kirchhoff's voltage law mesh loop method to get four expressions, namely:

[0046]

[0047] In the formula, d=-jωM,

[0048] The circuit resonance condition is:

[0049]

[0050] In the formula, ω0 is the coupling resonant frequency. When the entire system is in a resonant state, the circuit is purely resistive to the outside.

[0051] After rearranging the above formula, the expressions of each current phasor in the system resonance state are obtained as follows:

[0052]

[0053] because Figure 5 The resistance of the primary and secondary coils and the parasitic resistance of the inductors and capacitors are ignored, so the model is a lossless model. Under the lossless model, the output power of the LCC resonant compensation network DWPT is consistent with the input power, which can be expressed as:

[0054]

[0055] The conclusion can be drawn from the formula: output power P out With ω0 2 Inversely proportional to U in 2 Proportional to M 2 Proportional to R L Directly proportional.

[0056] When the system parameters are determined, P out It is only positively correlated with the mutual inductance M of the magnetic coupling mechanism. When the primary and secondary coils are decoupled, the resonant network is in a high-impedance open-circuit state to the voltage source. The power output mainly depends on the mutual inductance M. Therefore, under this condition, when the mutual inductance is stable, the output power reaches a stable state, that is, when the mutual inductance is stable during the movement of the power receiving body, the purpose of suppressing power fluctuations is achieved.

[0057] The rectifier and filter module is a single-phase bridge rectifier circuit, which includes four rectifier diodes and filter capacitors, and plays the role of rectification and filtering. It can convert the received high-frequency AC power into stable DC power to supply the battery.

[0058] The complementary coupling system for dynamic wireless power transmission described in the present application adopts dynamic wireless power transmission technology to solve the range anxiety problem of many mobile power receivers. It utilizes the different characteristics of monopole coils and multipole coils to overcome the cross-coupling problem between primary coils without adding additional compensation devices, greatly simplifying the design difficulty of compensation parameters. It adopts an integrated coupling compensation strategy between receiving coils and different types of transmitting coils. It only needs to simply adjust the number of coil turns to make the mutual inductance smooth and stable, thereby making the output power smooth and stable, which is of great significance to further improve the dynamic wireless power transmission technology.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0060] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A complementary coupling system for dynamic wireless power transmission, characterized in that: It includes a segmented DC bus, an inverter-control module, a compensation network, a multi-pole transmitting coil, a monopole transmitting coil, an integrated receiving coil and a rectifier filter module; The segmented DC bus supplies the DC power obtained after rectification of the industrial frequency power grid to the inverter-control module of the corresponding section, and the inverter-control module inverts the DC power into high-frequency AC power. The inverted high-frequency AC power resonates with the multi-pole transmitting coil or the monopole transmitting coil of the primary side through the compensation network of the primary side, transfers energy to the integrated receiving coil based on the near-field resonant coupling principle, resonates with the integrated receiving coil through the compensation network of the secondary side, and then converts the high-frequency AC power into stable DC power through the rectification and filtering module and outputs it to the vehicle battery; The multipolar transmitting coil and the monopolar transmitting coil located on the primary side are alternately laid, and the integrated receiving coil is formed by superimposing a multipolar receiving coil and a monopolar receiving coil in series.

2. The system according to claim 1, characterized in that: The DC power in the segmented DC bus is obtained by rectifying the 50Hz / 380V industrial frequency power grid through an electric energy converter, and the segmented DC bus power distribution is used to supply power to multiple wireless power supply segments in time and segment.

3. The system according to claim 1, characterized in that: The monopole transmitting coil and the monopole receiving coil are composed of a single coil structure, and the current generated on the coil flows in a single direction, forming a relatively concentrated magnetic field region with consistent direction.

4. The system according to claim 1, characterized in that: The multi-pole transmitting coil and the multi-pole receiving coil are composed of a plurality of coils, and the number of magnetic poles is 2k (k=1, 2, . . . ), so as to generate magnetic fields in two directions and form a uniform and wide magnetic field area.

5. The system according to claim 1, characterized in that: The coil shape adopts a square structure or a circular structure.

6. The system according to claim 1, characterized in that: The compensation network includes a primary side LCC compensation network and a secondary side LCC compensation network; The primary LCC compensation network includes a primary compensation inductor and a primary compensation capacitor, and the secondary LCC compensation network includes a secondary compensation inductor and a secondary compensation capacitor; wherein both ends of the primary transmitting coil and the secondary transmitting coil are respectively connected to the common side endpoints of the primary and secondary compensation capacitors.

7. The system according to claim 6, characterized in that The relationship between the output power and input power of the LCC resonant compensation network under the lossless model is expressed as: Where U in is the input voltage, I f2 is the secondary resonant current, L f1 and L f2 are the primary compensation inductor and the secondary compensation inductor respectively, M is the mutual inductance between the primary and secondary coils, R L is the equivalent load.

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