A dual-load electric vehicle wireless charging system with automatic switching between single and dual outputs

Abstract

The present invention relates to the technical field of wireless power transmission for electric vehicles, and specifically discloses a wireless charging system for electric vehicles with dual loads and automatic switching between single and dual outputs. By setting a primary switching circuit, the corresponding energy transmitting coil is automatically cut into the circuit according to the position of the energy receiving coil to transmit electric energy. Two electric vehicles can be charged at the same time, or only one electric vehicle can be charged, that is, automatic switching between single and dual outputs is realized. When charging an electric vehicle, the other non-working energy transmitting coil is replaced with a replacement inductor, which can prevent the transmitting coil from transmitting energy to objects in the surrounding space and causing unnecessary energy loss. The magnetic coupling mechanism designed in this system can eliminate cross-coupling of the two pairs of dual-receiving coils directly from the structure of the magnetic coupling mechanism, greatly enhancing the anti-interference ability of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission for electric vehicles, and in particular to a wireless charging system for electric vehicles with double loads and automatic switching between single and double outputs. Background Art

[0002] Wireless power transmission technology transmits energy through magnetic fields, electric fields and other media. Compared with wired charging technology, it has many advantages. Since wireless power transmission technology does not directly connect the power supply and the load with wires, it can directly avoid poor contact, electric sparks and other safety hazards caused by the aging of wires that transmit power. It is also more convenient to lay and install wireless power transmission systems than wired power transmission. Electric vehicles are developing rapidly, and applying wireless charging technology to electric vehicles will greatly increase the charging efficiency of electric vehicles.

[0003] In addition to powering a single load, wireless power transmission technology can also power two loads. Dual-load wireless power transmission technology greatly increases the power supply efficiency of electric vehicles. However, the current dual-load wireless power transmission system has disadvantages: regardless of whether it is a single-transmit-dual-receive or dual-transmit-dual-receive wireless power transmission system, the cross-coupling between the two receiving coils cannot be directly eliminated through the coil structure, causing the two receiving circuits to affect each other, and the addition of compensation impedance for decoupling will make the system circuit more complicated and affect its working stability; the two energy transmitting coils of the traditional dual-transmit-dual-receive wireless power transmission system have only two structures: parallel and series. For the parallel structure, two primary compensation circuits are required, which increases the cost. For the series structure, since the dual-output system will have a load connected, at this time, although the other energy transmitting coil has no load connected, it still emits electromagnetic waves into the environment, resulting in unnecessary energy loss. Summary of the invention

[0004] The present invention provides a single-double output automatic switching dual-load wireless charging system for electric vehicles, and solves the technical problems of how to reduce the use of primary compensation circuits in a dual-output wireless power transmission system without wasting more energy, and how to eliminate cross-coupling directly from the structure of a magnetic coupling mechanism for two pairs of dual-receiving coils.

[0005] In order to solve the above technical problems, the present invention provides a single-double output automatic switching dual-load electric vehicle wireless charging system, which is provided with a primary resonance compensation circuit and a magnetic coupling mechanism. The magnetic coupling mechanism includes a transmitting mechanism and a receiving mechanism. The transmitting mechanism includes a first energy transmitting coil L connected in series in series between one end and the other end of the primary resonance compensation circuit. 11 and the second energy transmitting coil L 21 The receiving mechanism includes the first energy transmitting coil L 11and the second energy transmitting coil L 21 The first energy receiving coil L is facing 12 and the second energy receiving coil L 22 , the system further comprises a primary side switching circuit;

[0006] The primary switching circuit includes a switch controller and a probe A, a probe B, a first switch S1, a second switch S2, a third switch S3 and a fourth switch S4 independently connected to the switch controller, and also includes a replacement inductor L3, the second switch S2 is connected in series between the primary resonance compensation circuit and the first energy transmitting coil L 11 The third switch S3 is connected in series between the primary resonance compensation circuit and the second energy transmitting coil L 21 The first switch S1 and the fourth switch S4 are sequentially connected in series between one end and the other end of the primary resonance compensation circuit, and the replacement inductor L3 is connected between the common connection end of the first switch S1 and the fourth switch S4 and the first energy transmitting coil L 11 With the second energy transmitting coil L 21 between the common connection ends;

[0007] The probe A and the probe B are respectively used to transmit the energy of the first energy transmitting coil L 11 , the second energy transmitting coil L 21 The charging position of the first energy receiving coil L is detected 12 , the second energy receiving coil L 22 When the probe A and the probe B send corresponding signals to the switch controller, the switch controller is used to control the on and off of the four switches according to the signals sent by the probe A and the probe B.

[0008] Specifically, the switch controller is used to control the on and off of the four switches according to the signals sent by the probes A and B:

[0009] When only the probe A is in the first energy transmitting coil L 11 The charging position of the first energy receiving coil L is detected 12 When the switch controller controls the second switch S2 and the fourth switch S4 to be turned on, and the first switch S1 and the third switch S3 to be turned off, the replacement inductor L3 and the first energy transmitting coil L 11 is switched into the circuit, the second energy transmitting coil L 21 The circuit is cut out to realize the first energy receiving coil L 12 Single output power supply;

[0010] When only the probe B is in the second energy transmitting coil L 21 The charging position of the second energy receiving coil L is detected 22 When the switch controller controls the second switch S2 and the fourth switch S4 to be disconnected, and the first switch S1 and the third switch S3 to be connected, the replacement inductor L3 and the second energy transmitting coil L 21 is switched into the circuit, the first energy transmitting coil L 11 The circuit is cut out to realize the second energy receiving coil L 22 Single output power supply;

[0011] When the probe A is in the first energy transmitting coil L 11 The charging position of the first energy receiving coil L is detected 12 , the probe B is simultaneously in the second energy transmitting coil L 21 The charging position of the second energy receiving coil L is detected 22 When the switch controller controls the second switch S2 and the third switch S3 to be turned on, and the first switch S1 and the fourth switch S4 to be turned off, the replacement inductor L3 is cut out of the circuit, and two energy transmitting coils are connected to the circuit to realize dual output power supply for two energy receiving coils at the same time.

[0012] Specifically, the first energy transmitting coil L 11 With the first energy receiving coil L 12 A first DD-type coil with the same structure and size and parallel to each other is used, wherein the first DD-type coil is composed of two first D-type coils arranged transversely and wound in opposite directions and connected in series;

[0013] The second energy transmitting coil L 21 The second energy receiving coil L 22 A second DD-type coil having the same structure and size and being parallel to each other is used, wherein the second DD-type coil is formed by two second D-type coils arranged longitudinally and wound in opposite directions and connected in series.

[0014] Specifically, the transmitting mechanism further includes an intermediate magnetic core sandwiched between the two energy transmitting coils, and the receiving mechanism further includes a magnetic core close to the first energy receiving coil L 12 The first secondary magnetic core and the second energy receiving coil L are close to each other 22 The second secondary magnetic core;

[0015] The first secondary magnetic core is formed by a plurality of first strip-shaped magnetic cores placed transversely and arranged longitudinally at equal distances;

[0016] The second secondary magnetic core is formed by a plurality of second strip magnetic cores placed longitudinally and arranged laterally at equal distances;

[0017] The middle magnetic core is formed by orthogonally overlapping two magnetic cores that are respectively identical to the first secondary magnetic core and the second secondary magnetic core.

[0018] Specifically, the first D-type coil and the second D-type coil are both D-type coils, i.e. rectangular coils, with a length of a and a width of 0.5a; the first bar magnetic core and the second bar magnetic core are both bar magnets with a length of a, a thickness of h, and a width of w.

[0019] Specifically, the thickness h and width w of the bar magnet are determined by the first energy transmitting coil L. 11 With the first energy receiving coil L 12 The required coupling coefficient k between the two and the minimum volume of each bar magnet when the required coupling coefficient k is achieved are jointly determined.

[0020] Specifically, the specific steps of determining the thickness h and width w of the bar magnet include:

[0021] S1, using simulation software to draw a contour image P1 of the coupling coefficient k as the thickness h and width w change;

[0022] S2, according to the system input voltage U i and the required output voltage U o Determine the coupling coefficient And obtain the contour line l1 of the coupling coefficient k on the contour image P1;

[0023] S3, draw contour images P2 of the volume V=a·h·w of different bar magnets as the thickness h and width w of the bar magnetic core change, and the two coordinate axes of the contour images P1 and P2 are exactly the same;

[0024] S4. Take the contour line l2 on the contour image P2 corresponding to the contour line l1 on the contour image P1, take the contour line l3 on the contour image P2 that intersects with the contour line l2 and minimizes V=a·hw, and take the thickness h and width w corresponding to the intersection of the contour line l2 and the contour line l3.

[0025] Specifically, the system is further provided with an AC source, a primary side rectifier circuit, an inverter circuit connected in sequence, a first secondary side resonant compensation circuit, a first secondary side rectifier circuit, a first automobile load connected in sequence, a second secondary side resonant compensation circuit, a second secondary side rectifier circuit, and a second automobile load connected in sequence, wherein the inverter circuit is connected to the primary side resonant compensation circuit, and the first secondary side resonant compensation circuit is connected to the first energy receiving coil L 12 The second secondary resonance compensation circuit is connected to the second energy receiving coil L22 Connection

[0026] Specifically, the primary resonant compensation circuit adopts an LCC compensation network, including a primary series resonant inductor L0, a primary series resonant capacitor C0, and a primary parallel resonant capacitor C1. The first secondary resonant compensation circuit adopts a first secondary series resonant capacitor C 12 , and the second secondary resonant compensation circuit adopts a second secondary series resonant capacitor C 22 .

[0027] Specifically, the inductance values of the 2 energy transmitting coils, the 2 energy receiving coils, and the replacement inductor L3 are all L;

[0028] The primary series resonant inductor L0 = 2pL, where 0 < p < 1, and p is a scaling factor such that the primary series resonant inductor L0 is less than the total inductance 2L of the two energy transmitting coils;

[0029] The primary series resonant capacitor ω represents the operating angular frequency of the system;

[0030] The primary parallel compensation capacitor

[0031] The first secondary series resonant capacitor

[0032] A single - double output automatic - switching dual - load electric vehicle wireless charging system provided by the present invention, by setting a primary switching circuit, automatically cuts the corresponding energy transmitting coil into the circuit according to the position of the energy receiving coil for power transmission, can charge two electric vehicles simultaneously, or can only charge one electric vehicle, that is, realizes the automatic switching of single - double output. And when charging one electric vehicle, the other non - working energy transmitting coil is replaced by a replacement inductor, which can prevent this transmitting coil from emitting energy to objects in the surrounding space, causing unnecessary energy loss. The magnetic coupling mechanism designed in this system can directly eliminate cross - coupling from the structure of the magnetic coupling mechanism for the two pairs of double - receiving coils, greatly enhancing the anti - interference ability of the system. Brief Description of the Drawings

[0033] Figure 1 is the circuit topology diagram of a single - double output automatic - switching dual - load electric vehicle wireless charging system provided by an embodiment of the present invention;

[0034] Figure 2 is the structural schematic diagram of the magnetic coupling mechanism provided by an embodiment of the present invention;

[0035] Figure 3 is the contour map of the coupling coefficient k between the energy transmitting coil and the energy receiving coil provided by an embodiment of the present invention varying with the thickness h and width w of the bar magnet;

[0036] Figure 4 is a contour diagram of the volume V of each bar magnet provided by an embodiment of the present invention as a function of its thickness h and width w;

[0037] Figure 5 It is a schematic diagram of the simulation value of the coupling coefficient of the magnetic coupling mechanism in Maxwell provided by an embodiment of the present invention;

[0038] Figure 6 is a waveform diagram of the system input voltage and input current under double load in the simulation provided by the embodiment of the present invention;

[0039] Figure 7 is a waveform diagram of the system input voltage and input current under single load in the simulation provided by an embodiment of the present invention;

[0040] Figure 8 is the second energy receiving coil L in the simulation provided by the embodiment of the present invention 22 Waveforms of the two load voltages when replaced by the replaced inductor L3;

[0041] Fig. 9 is the second energy receiving coil L in the simulation provided by the embodiment of the present invention 22 The waveforms of the two load voltages when the circuit is switched in and the inductor L3 is replaced and switched out. DETAILED DESCRIPTION

[0042] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and cannot be understood as limiting the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention, because many changes can be made to the present invention without departing from the spirit and scope of the present invention.

[0043] In order to reduce the use of primary compensation circuits in dual-output wireless power transmission systems without wasting more energy, such as Figure 1 As shown in the system circuit topology diagram, an embodiment of the present invention provides a single-dual output automatic switching dual-load electric vehicle wireless charging system, which is provided with a sequentially connected AC source (AC input), a primary side rectifier circuit (rectifier link), an inverter circuit (inverter link), a primary side resonance compensation circuit, and a magnetic coupling mechanism. The magnetic coupling mechanism includes a transmitting mechanism and a receiving mechanism. The transmitting mechanism includes a first energy transmitting coil L sequentially connected in series between one end and the other end of the primary side resonance compensation circuit. 11 and the second energy transmitting coil L 21 The receiving mechanism includes a first energy transmitting coil L 11 and the second energy transmitting coil L 21 The first energy receiving coil L is facing 12and the second energy receiving coil L 22 , where the first energy receiving coil L 12 Installed in electric vehicle A, the second energy receiving coil L 22 Installed in electric vehicle B, electric vehicle A is also provided with a first secondary side resonant compensation circuit, a first secondary side rectifier circuit (rectifier link), and a first vehicle load R1 connected in sequence, and electric vehicle B is also provided with a second secondary side resonant compensation circuit, a second secondary side rectifier circuit (rectifier link), and a second vehicle load R2 connected in sequence, and the first secondary side resonant compensation circuit is connected to the first energy receiving coil L 12 The second secondary resonance compensation circuit is connected to the second energy receiving coil L 22 The primary resonance compensation circuit adopts an LCC compensation network, including a primary series resonant inductor L0, a primary series resonant capacitor C0 and a primary parallel resonant capacitor C1. The first secondary resonance compensation circuit adopts a first secondary series resonant capacitor C 12 The second secondary side resonant compensation circuit uses the second secondary side series resonant capacitor C 22 .

[0044] The above designs are all conventional designs and will not be described in detail in this example. The key point of this system is that the system also has a primary side switching circuit. Figure 1 The primary switching circuit includes a switch controller and a probe A, a probe B, a first switch S1, a second switch S2, a third switch S3 and a fourth switch S4 independently connected to the switch controller, and also includes a replacement inductor L3, the second switch S2 is connected in series between the primary resonance compensation circuit and the first energy transmitting coil L 11 The third switch S3 is connected in series between the primary resonance compensation circuit and the second energy transmitting coil L 21 The first switch S1 and the fourth switch S4 are sequentially connected in series between one end and the other end of the primary resonance compensation circuit, and the replacement inductor L3 is connected between the common connection end of the first switch S1 and the fourth switch S4 and the first energy transmitting coil L 11 With the second energy transmitting coil L 21 between the common connection terminals.

[0045] Probe A and probe B are used to transmit energy in the first energy transmitting coil L 11 , the second energy transmitting coil L 21 The charging position detects the first energy receiving coil L 12 , the second energy receiving coil L 22 The switch controller is used to control the on and off of the four switches according to the signals sent by probe A and probe B. The specific control process is as follows:

[0046] When only probe A is in the first energy transmitting coil L 11 The charging position detects the first energy receiving coil L 12 When the switch controller controls the second switch S2 and the fourth switch S4 to be turned on, the first switch S1 and the third switch S3 to be turned off, and the inductor L3 and the first energy transmitting coil L are replaced. 11 The second energy transmitting coil L is cut into the circuit. 21 The circuit is cut out, L0, C0, C1, L 11 , L3 form a resonant circuit to ensure the normal operation of the compensation circuit, and to achieve only the first energy receiving coil L 12 Single output power supply.

[0047] When only probe B is in the second energy transmitting coil L 21 The charging position detects the second energy receiving coil L 22 When the switch controller controls the second switch S2 and the fourth switch S4 to be disconnected, the first switch S1 and the third switch S3 to be connected, and the inductor L3 and the second energy transmitting coil L are replaced. 21 The first energy transmitting coil L is cut into the circuit. 11 Cut out circuit, L0, C0, C1, L3, L 21 A resonant circuit is formed to ensure that the compensation circuit works normally and only the second energy receiving coil L 22 Single output power supply.

[0048] When the probe A is in the first energy transmitting coil L 11 The charging position detects the first energy receiving coil L 12 , probe B is simultaneously in the second energy transmitting coil L 21 The charging position detects the second energy receiving coil L 22 When the switch controller controls the second switch S2 and the third switch S3 to be turned on, the first switch S1 and the fourth switch S4 to be turned off, at which time the replacement inductor L3 is cut out of the circuit, and the two energy transmitting coils are connected to the circuit, L0, C0, C1, L 11 , L 21 A resonant circuit is formed to realize dual-output power supply for two energy receiving coils at the same time.

[0049] When neither probe A nor probe B detects an electric vehicle, the system does not work.

[0050] When only L 11 or L 21When one of the energy transmitting coils is working, that is, only one load is connected to the circuit, the replacement inductor L3 is connected to the circuit to replace the non-working energy transmitting coil, the purpose of which is to keep the system parameters unchanged and keep the system in a resonant state. If the replacement inductor L3 is not used to replace the non-working energy transmitting coil, the energy transmitting coil will still transmit energy into the space, causing eddy current loss in the surrounding metal and other objects that generate eddy current, resulting in unnecessary energy loss.

[0051] In order to eliminate the cross coupling of the two pairs of coils for dual reception directly from the structure of the magnetic coupling mechanism, such as Figure 2 As shown in the structural diagram, this embodiment sets a first energy transmitting coil L 11 With the first energy receiving coil L 12 A first DD-type coil with the same structure, size and parallel to each other is used, and the first DD-type coil is composed of two first D-type coils arranged horizontally and wound in opposite directions in series. 21 With the second energy receiving coil L 22 A second DD-type coil having the same structure and size and being parallel to each other is adopted, and the second DD-type coil is composed of two second D-type coils arranged longitudinally and wound in opposite directions and connected in series.

[0052] The transmitting mechanism also includes an intermediate magnetic core sandwiched between the two energy transmitting coils, and the receiving mechanism also includes a first energy receiving coil L 12 The first secondary magnetic core and the second energy receiving coil L are close to each other. 22 The second secondary core;

[0053] The first secondary magnetic core is formed by a plurality of first strip magnetic cores placed transversely and arranged longitudinally at equal distances;

[0054] The second secondary magnetic core is formed by a plurality of second strip magnetic cores placed longitudinally and arranged laterally at equal distances;

[0055] The middle magnetic core is formed by orthogonally overlapping two magnetic cores which are respectively identical to the first secondary magnetic core and the second secondary magnetic core.

[0056] With such a design, the coupling coefficient between any coil in the first pair of transceiver coils and any coil in the second pair of transceiver coils is equal to 0 due to the characteristics of the DD type coils and their orthogonal relationship, which means that no induced voltage will be generated between the two pairs of coils, that is, decoupling.

[0057] For better system performance, the first D-type coil and the second D-type coil both use D-type coils with a length of a and a width of 0.5a, i.e. rectangular coils, and the first bar core and the second bar core both use bar magnets with a length of a, a thickness of h, and a width of w. The thickness h and width w of the bar magnet are determined by the first energy transmitting coil L. 11With the first energy receiving coil L 12 The required coupling coefficient k between the two and the minimum volume of each bar magnet when the required coupling coefficient k is achieved are jointly determined, and the specific steps of determining include:

[0058] S1, using simulation software to draw a contour image P1 of the coupling coefficient k as the thickness h and width w change;

[0059] S2, according to the system input voltage U i and the required output voltage U o Determine the coupling coefficient And obtain the contour line l1 of the coupling coefficient k on the contour image P1;

[0060] S3, draw contour images P2 of the volume V=a·h·w of different bar magnets as the thickness h and width w of the bar magnetic core change, and the two coordinate axes of the contour images P1 and P2 are exactly the same;

[0061] S4. Take the contour line l2 on the contour image P2 corresponding to the contour line l1 on the contour image P1, take the contour line l3 on the contour image P2 that intersects with the contour line l2 and minimizes V=a·hw, and take the thickness h and width w corresponding to the intersection of the contour line l2 and the contour line l3.

[0062] This core selection method not only takes into account the optimization of the system's output performance, but also minimizes the material usage of the core.

[0063] In the specific experiment, a=300mm, and there are 6 bar magnets. Figure 3 P1 is the contour image of the coupling coefficient k between the energy transmitting coil and the energy receiving coil changing with the thickness h and width w of the magnet. The abscissa is the thickness h of the bar magnet, and the ordinate is the ratio of the total width 6w of the 6 bar magnets to the side length a of the coil. In the figure, L1 (also known as l1) is the contour line of k=0.455, which is approximately equal to 0.46. Figure 4 The contour image P2 is a graph showing the volume V of each bar magnet as it changes with the thickness h and width w of the magnet. In the graph, l2 is the contour line of k=0.46, and l3 is the contour line of the minimum volume V passing through l2. The intersection points D1 and D2 are the thickness h and width w values ​​of the magnet that satisfy k=0.46 and obtain the minimum bar magnet volume V. In this example, (4, 0.65) is taken, that is, h=4mm, w=32.5mm.

[0064] In addition, in other parameter designs, in order to improve transmission efficiency and reduce system losses, the imaginary part of the system input impedance should be zero. From the perspective of system resonance, see Figure 1 The primary series resonant inductor L0 and the primary parallel resonant capacitor C1 form a resonant circuit. The two energy transmitting coils L11 +L 21 The primary - side series - resonance capacitor C0 and the primary - side parallel - resonance capacitor C1 form a resonance circuit. The first secondary - side series - resonance capacitor C 12 and the first energy - receiving coil L 12 form a resonance circuit. The second secondary - side series - resonance capacitor C 22 and the second energy - receiving coil L 22 form a resonance circuit. Then

[0065]

[0066] Therefore, the value of the primary - side series - resonance inductor L0 should be less than the total inductance of the two energy - transmitting coils L 11 +L 21 . Let L0 = p(L 11 +L 21 ), where 0 < p < 1, and p is the proportionality factor that makes the primary - side series - resonance inductor L0 less than the total inductance of the two energy - transmitting coils L 11 +L 21 .

[0067] Since L 11 = L 21 = L3 = L 12 = L 22 = L, that is, L0 = 2pL(0 < p < 1).

[0068] Therefore, the capacitance value should satisfy:

[0069]

[0070] As Figure 5 shown, it is the simulation value of the coupling coefficient of the magnetic - coupling mechanism of the present invention in Maxwell, where h = 4mm, w = 32.5mm. Group1, Group2, Group3, and Group4 are the first energy - transmitting coil, the first energy - receiving coil, the second energy - transmitting coil, and the second energy - receiving coil respectively. The coupling coefficient between the first energy - transmitting coil and the second energy - transmitting coil is approximately 1.414×10 -4 , the coupling coefficient between the first energy - transmitting coil and the second energy - receiving coil is approximately 1.538×10 -6 , the coupling coefficient between the second energy - transmitting coil and the first energy - receiving coil is approximately 3.860×10 -6 , and the coupling coefficient between the first energy - transmitting coil and the second receiving - transmitting coil is approximately 2.622×10 -6, can be considered equal to 0 within the simulation error range of Maxwell, that is, the coupling coefficient between any coil in the first pair of coils and any coil in the second pair of coils is zero, indicating that the invented magnetic coupling mechanism can completely eliminate the cross-coupling between the two pairs of coils in its own structure.

[0071] This example follows Figure 1 , the corresponding Simulink simulation model was built, where the load equivalent resistance R1 = R2 = 5Ω, the system input sinusoidal voltage effective value U i =100V, frequency f is 85kHz, L 11 =L 21 =L 12 =L 22 =L3=150μH, p is 0.6, then the system parameters are:

[0072] L0=2pL=180μH,

[0073]

[0074] The system switches from the dual-load state to the single-load state at 0.1s, the load R2 is cut out of the circuit, and the inductor L3 replaces the second energy transmitting coil L 21 The circuit is connected and switched from a single load state to a double load state at 0.2s. Load R2 is switched into the circuit and inductor L3 is replaced and switched out of the circuit. The second energy transmitting coil L 21 Access circuit.

[0075] Figure 6 The input voltage and input current of the system under double load are shown in Figure 2. Figure 7 The image of the system input voltage and input current under single load is shown by Figure 6 , Figure 7 It can be seen that no matter in double load or single load, the phase difference between the input voltage and input current of the system is 0, and the system is in resonance state. This shows that the system can make the dual-transmitter-dual-receiver system work normally while saving the use of one primary resonant circuit.

[0076] Figure 8 L is the second energy transmitting coil in the system 21 When the replaced inductor L3 is replaced, that is, when the system changes from a double load to a single load state, the voltage image of the two loads of the system. In this process, the voltage U of load R1 o1 The voltage U of load R2 increases first and returns to normal after 0.001s. o2 Gradually decrease to 0 within 0.001s.

[0077] Fig. 9 L is the second energy transmitting coil in the system21 When the circuit is switched on and the inductor L3 is replaced and switched off, that is, when the system changes from a single load to a double load state, the voltage image of the two loads of the system. In this process, the voltage U of the load R1 o1 The voltage U of load R2 decreases first and then returns to normal after 0.001s. o2 It gradually increases to the normal value within 0.001s, which shows that the system can still work stably when the load quantity changes.

[0078] Figures 6 to 9 It shows that after the primary switching circuit is designed in this system, the dual-transmitting and dual-receiving system can work normally and stably while saving the use of one primary-side resonant circuit.

[0079] In summary, the embodiment of the present invention provides a dual-load wireless charging system for electric vehicles with automatic switching between single and dual outputs. By setting a primary switching circuit, the corresponding energy transmitting coil is automatically cut into the circuit according to the position of the energy receiving coil to transmit electric energy. It can charge two electric vehicles at the same time, or only charge one electric vehicle, that is, it realizes automatic switching between single and dual outputs. When charging an electric vehicle, the other non-working energy transmitting coil is replaced with a replacement inductor, which can prevent the transmitting coil from transmitting energy to objects in the surrounding space and causing unnecessary energy loss. The magnetic coupling mechanism designed in this system can eliminate cross-coupling of the two pairs of dual-receiving coils directly from the structure of the magnetic coupling mechanism, greatly enhancing the anti-interference ability of the system.

[0080] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A single-dual output automatic switching dual-load electric vehicle wireless charging system, provided with a primary resonance compensation circuit, a magnetic coupling mechanism, the magnetic coupling mechanism includes a transmitting mechanism and a receiving mechanism, the transmitting mechanism includes a first energy transmitting coil (L) connected in series between one end and the other end of the primary resonance compensation circuit 11 ) and the second energy transmitting coil (L 21 ), the receiving mechanism includes the first energy transmitting coil (L 11 ) and the second energy transmitting coil (L 21 ) is facing the first energy receiving coil (L 12 ) and the second energy receiving coil (L 22 ), characterized in that The system further includes a primary side switching circuit; The primary switching circuit includes a switch controller and a probe A, a probe B, a first switch (S1), a second switch (S2), a third switch (S3) and a fourth switch (S4) independently connected to the switch controller, and also includes a replacement inductor (L3), wherein the second switch (S2) is connected in series between the primary resonance compensation circuit and the first energy transmitting coil (L 11 ), the third switch (S3) is connected in series between the primary resonance compensation circuit and the second energy transmitting coil (L 21 ), the first switch (S1) and the fourth switch (S4) are sequentially connected in series between one end and the other end of the primary resonance compensation circuit, and the replacement inductor (L3) is connected between the common connection end of the first switch (S1) and the fourth switch (S4) and the first energy transmitting coil (L 11 ) and the second energy transmitting coil (L 21 ) between the common connection ends; The probe A and the probe B are used to respectively transmit the energy of the first energy transmitting coil (L 11 )、The second energy transmitting coil (L 21 ) detects the first energy receiving coil (L 12 ), the second energy receiving coil (L 22 ) sends a corresponding signal to the switch controller, and the switch controller is used to control the on and off of the four switches according to the signals sent by the probes A and B; The first energy transmitting coil (L 11 ) and the first energy receiving coil (L 12 ) using a first DD-type coil with the same structure and size and parallel to each other, wherein the first DD-type coil is composed of two first D-type coils arranged transversely and wound in opposite directions in series; The second energy transmitting coil (L 21 ) and the second energy receiving coil (L 22 ) using a second DD-type coil with the same structure and size and parallel to each other, wherein the second DD-type coil is composed of two second D-type coils arranged longitudinally and wound in opposite directions connected in series; The transmitting mechanism also includes an intermediate magnetic core sandwiched between the two energy transmitting coils, and the receiving mechanism also includes a magnetic core close to the first energy receiving coil (L 12 ) of the first secondary magnetic core and the second energy receiving coil (L 22 ) of the second secondary core; The first secondary core is formed by arranging a plurality of first strip cores placed horizontally at equal intervals in the longitudinal direction; The second secondary core is formed by arranging a plurality of second strip cores placed vertically at equal intervals in the transverse direction; The intermediate core is formed by orthogonally overlapping two cores that are respectively the same as the first secondary core and the second secondary core.

2. According to claim 1, a dual-load electric vehicle wireless charging system with automatic switching between single and dual outputs is characterized in that: The switch controller is used to control the on / off of the 4 switching switches according to the signals sent by the probe A and the probe B. Specifically: When only the probe A is in the first energy transmitting coil (L 11 ) detects the first energy receiving coil (L 12 ), the switch controller controls the second switch (S2) and the fourth switch (S4) to be turned on, and the first switch (S1) and the third switch (S3) to be turned off. At this time, the replacement inductor (L3) and the first energy transmitting coil (L 11 ) is cut into the circuit, the second energy transmitting coil (L 21 ) is cut out of the circuit, so that only the first energy receiving coil (L 12 ) single output power supply; When only the probe B is in the second energy transmitting coil (L 21 ) detects the second energy receiving coil (L 22 ), the switch controller controls the second switch (S2) and the fourth switch (S4) to be disconnected, and the first switch (S1) and the third switch (S3) to be connected, at which time the replacement inductor (L3) and the second energy transmitting coil (L 21 ) is cut into the circuit, the first energy transmitting coil (L 11 ) is cut out of the circuit, so that only the second energy receiving coil (L 22 ) single output power supply; When the probe A is in the first energy transmitting coil (L 11 ) detects the first energy receiving coil (L 12 ), the probe B is simultaneously in the second energy transmitting coil (L 21 ) detects the second energy receiving coil (L 22 ), the switch controller controls the second switch (S2) and the third switch (S3) to be turned on, and the first switch (S1) and the fourth switch (S4) to be turned off. At this time, the replacement inductor (L3) is cut out of the circuit, and the two energy transmitting coils are connected to the circuit, so as to realize dual output power supply for the two energy receiving coils at the same time.

3. According to claim 1, a dual-load electric vehicle wireless charging system with automatic switching between single and dual outputs is characterized in that: Both the first D-shaped coil and the second D-shaped coil are D-shaped coils (i.e., rectangular coils) with a length of a and a width of 0.5a; both the first strip core and the second strip core are strip magnets with a length of a, a thickness of h, and a width of w.

4. According to claim 3, a dual-load electric vehicle wireless charging system with automatic switching between single and dual outputs is characterized in that: The thickness h and width w of the bar magnet are determined by the first energy transmitting coil (L 11 ) and the first energy receiving coil (L 12 ) and the minimum volume of each of the bar magnets when the required coupling coefficient k is achieved are jointly determined.

5. The single-double output automatic switching dual-load electric vehicle wireless charging system according to claim 4 is characterized in that: The specific steps for determining the thickness h and width w of the strip magnet include: S1. Use simulation software to draw the contour line image P1 of the coupling coefficient k varying with the thickness h and width w; S2, according to the system input voltage U i and the required output voltage U o Determine the coupling coefficient And obtain the contour line l1 of the coupling coefficient k on the contour image P1; S3. Draw the contour line image P2 of the volume V = a·h·w of different strip magnets varying with the thickness h and width w of the strip core. The two coordinate axes of the contour line image P1 and the contour line image P2 are exactly the same; S4. Take the contour line l2 on the contour line image P2 corresponding to the contour line l1 on the contour line image P1, take the contour line l3 on the contour line image P2 that intersects with the contour line l2 and makes V = a·h·w the smallest, and take the thickness h and width w corresponding to the intersection point of the contour line l2 and the contour line l3.

6. The single-double output automatic switching dual-load electric vehicle wireless charging system according to claim 1 is characterized in that: The system is also provided with an AC source, a primary side rectifier circuit, an inverter circuit connected in sequence, a first secondary side resonant compensation circuit, a first secondary side rectifier circuit, a first automobile load connected in sequence, a second secondary side resonant compensation circuit, a second secondary side rectifier circuit, and a second automobile load connected in sequence, wherein the inverter circuit is connected to the primary side resonant compensation circuit, the first secondary side resonant compensation circuit is connected to the first energy receiving coil (L 12 ), the second secondary resonant compensation circuit is connected to the second energy receiving coil (L 22 )connect.

7. A single-double output automatic switching dual-load electric vehicle wireless charging system according to claim 6, characterized in that: The primary resonance compensation circuit adopts an LCC compensation network, including a primary series resonant inductor L0, a primary series resonant capacitor C0 and a primary parallel resonant capacitor C1. The first secondary resonance compensation circuit adopts a first secondary series resonant capacitor C 12 The second secondary side resonant compensation circuit adopts the second secondary side series resonant capacitor C 22 .

8. A dual-load electric vehicle wireless charging system with automatic single / double output switching according to claim 7, wherein The inductance values of the 2 energy transmitting coils, the 2 energy receiving coils, and the replacement inductor (L3) are all L; The primary side series resonance inductor L0 = 2pL, where 0 < p < 1, and p is a proportionality factor such that the primary side series resonance inductor L0 is less than the total inductance 2L of the two energy transmitting coils. Primary series resonant capacitor ω represents the operating angular frequency of the system; Primary parallel compensation capacitor

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