Stacked high capacitance bias magnetic coupling mechanism and design method based on anisotropic winding coils

Abstract

The present invention discloses a stacked high-capacitance magnetic coupling mechanism and design method based on anisotropically wound coils, wherein the coupling mechanism comprises a transmitting end and a receiving end; the transmitting end comprises a transmitting coil, a transmitting end magnetic core and a compensating coil; the transmitting end magnetic core is laid flat below the transmitting coil and is arranged close to the transmitting coil; the compensating coil is placed directly above the transmitting coil; the receiving end comprises a receiving coil and a receiving end magnetic core; the receiving coil is placed directly above the compensating coil of the transmitting end, and is used to couple with the transmitting coil to realize wireless charging; the receiving end magnetic core is laid flat above the receiving coil and is arranged close to the receiving coil; the transmitting coil, the compensating coil and the receiving coil are formed by two anisotropically wound coils connected in series. The high-capacitance magnetic coupling mechanism of the present invention has good anti-offset performance, and the mutual inductance of the coupling mechanism can still be kept relatively stable after the coil is offset.

Description

Technical Field

[0001] The invention belongs to the field of wireless power transmission, and in particular relates to a stacked high-capacitance-bias magnetic coupling mechanism based on anisotropically wound coils and a design method thereof. Background Art

[0002] Wireless power transmission refers to an energy transmission technology that transfers energy from the power supply side to the electrical equipment in a non-direct contact manner. It breaks away from the constraints of traditional charging methods such as wires and cables, has better adaptability and safety, and has received extensive attention and research from scholars at home and abroad as a new charging method.

[0003] The coupling mechanism is a key part of energy transfer in the wireless power transmission system. High-frequency alternating current is converted into a high-frequency magnetic field through the transmitting coil, and the high-frequency magnetic field is converted into the same-frequency alternating current through the receiving coil. After processing, the electric energy is transmitted to the load to realize wireless transmission of energy.

[0004] The existing magnetic coupling mechanism of wireless power transmission system focuses more on improving transmission efficiency and output power. However, the magnetic coupling mechanism is very prone to deviation, which leads to technical problems such as unstable transmission efficiency and transmission power in the system. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a stacked high-capacitance bias magnetic coupling mechanism and design method based on anisotropically wound coils. The advantage is that the coupling mechanism can improve the anti-deviation capability of the wireless charging system and solve the problem of poor anti-deviation performance of the existing magnetic coupling mechanism.

[0006] Invention content: The stacked high-capacitance-bias magnetic coupling mechanism based on anisotropically wound coils of the present invention includes a transmitting end and a receiving end; the transmitting end includes a transmitting coil, a transmitting end magnetic core and a compensating coil; the transmitting end magnetic core is laid flat under the transmitting coil and is arranged close to the transmitting coil; the compensating coil is placed directly above the transmitting coil; the receiving end includes a receiving coil and a receiving end magnetic core; the receiving coil is placed directly above the compensating coil of the transmitting end, and is used to couple with the transmitting coil to realize wireless charging; the receiving end magnetic core is laid flat above the receiving coil and is arranged close to the receiving coil; the transmitting coil, the compensating coil and the receiving coil are formed by two anisotropically wound coils connected in series.

[0007] The central axis of the transmitting coil, the central axis of the compensating coil, and the central axis of the receiving coil are coaxially arranged, which is the optimal alignment position, and the wireless charging efficiency is the highest at this time.

[0008] The transmitting coil and the compensating coil are wound with the same wire, which can avoid the generation of exposed wire interfaces and avoid additional losses at the wiring points.

[0009] The transmitting end magnetic core and the receiving end magnetic core are both made of rectangular ferrite material.

[0010] The present invention also includes a design method for a stacked high-capacitance-bias magnetic coupling mechanism based on anisotropically wound coils, comprising the following steps:

[0011] (i) Determine the size, number of turns and transmission height of the original transmitting coil and receiving coil, where the compensation coil radius R3=a, the number of turns of the compensation coil N3=1, and the transmission height h1=h;

[0012] (ii) Setting the minimum values ​​of the compensation coil structural parameters and the initial value of the transmission height;

[0013] (iii) setting the X and Y axis offset ranges, dividing the maximum offset distance into N intervals;

[0014] (iv) Set the initial values ​​x1 and x2 of the minimum and maximum offset tolerances in the X-axis offset direction, set the initial values ​​x3 and x4 of the minimum and maximum offset tolerances in the Y-axis offset direction, and set the original mutual inductance M tr1 The initial proportion of holdings a;

[0015] (V) Calculate the mutual inductance value M corresponding to the right endpoint value of the i-th interval in the X-axis offset direction i ; Calculate the mutual inductance value M corresponding to the right endpoint value of the i-th interval in the Y-axis offset direction j ; Where i,j=1,2,…,N;

[0016] (VI) Setting constraints, if the mutual inductance value M i and M j If the constraints are met, the compensation coil center radius R3, number of turns N3, and transmission height h1 are output.

[0017] In step (six), if the mutual inductance value M i and M j If the constraint condition is not met, the value of the compensation coil radius R3 is adjusted according to the formula R3=R3+ΔR3, where ΔR3=1mm, and it is determined whether the adjusted compensation coil radius R3 is not greater than the specified transmitting end size.

[0018] If the adjusted value of the compensation coil radius R3 is not greater than the specified transmitting end size, proceed to step (V).

[0019] If the adjusted value of the compensation coil radius R3 does not meet the requirement of being no greater than the specified transmitting end size, the value of the transmission height h1 is adjusted according to the formula R3=a, h1=h1+Δh1, where Δh1=1mm, and it is determined whether the adjusted value of the transmission height h1 meets the requirement of being no less than the set transmission gap.

[0020] If the adjusted transmission height h1 value does not meet the requirement of being not less than the set transmission gap, increase the number of turns of the compensation coil; determine whether the transmitting end meets the requirement of being not greater than the specified size after the number of turns of the compensation coil is increased. If not, proceed to step (iv).

[0021] The constraints set are:

[0022]

[0023] Where x1 and x2 are the initial values ​​of the minimum and maximum offset tolerance in the X-axis offset direction, respectively; x3 and x4 are the initial values ​​of the minimum and maximum offset tolerance in the Y-axis offset direction, respectively; σ i and σ j are the offset tolerance of each segmented test point on the X-axis and Y-axis respectively; M0 is the mutual inductance when the coupling mechanism is facing each other; M i and M j are the mutual inductance values ​​of each segmented test point on the X-axis and Y-axis after compensation; where i,j=1,2,…,N.

[0024] Beneficial effect: Compared with the prior art, the technical solution of the present invention has the following beneficial effects: the compensation coil can offset part of the magnetic flux directly above the center, reduce the magnetic flux density in the center, and reduce the magnetic flux coupling when the coupling mechanism is facing, so that the degree of magnetic flux coupling is similar to that in the offset situation, so that the mutual inductance before and after the offset is similar. Under ideal conditions, within a certain offset range, the mutual inductance does not change with the increase of the offset, and the mutual inductance offset curve remains horizontal, so the coupling mechanism has a higher anti-offset performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the stacked high-capacitance-bias magnetic coupling mechanism based on anisotropically wound coils according to the present invention;

[0026] Figure 2 A comparison diagram of magnetic field distribution of the stacked high capacitance ratio magnetic coupling mechanism based on anisotropically wound coils in the present invention before and after adding a supplementary coil;

[0027] Figure 3 It is a graph of the offset characteristic of the stacked high-capacitance-bias magnetic coupling mechanism based on the anisotropically wound coils according to the present invention;

[0028] Figure 4 This is a waveform diagram of the offset experiment of the stacked high-capacitance bias magnetic coupling mechanism based on the anisotropically wound coils according to the present invention;

[0029] Figure 5 The present invention is a flow chart of a design method for a stacked high-capacitance-bias magnetic coupling mechanism based on anisotropically wound coils. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings of the specification.

[0031] like Figure 1 As shown, the stacked high capacitance rate magnetic coupling mechanism based on the anisotropic winding coils of the present invention comprises a transmitting end and a receiving end, wherein the transmitting end comprises a transmitting coil 1, a transmitting end magnetic core 2 and a compensating coil 3; and the receiving end comprises a receiving coil 4 and a receiving end magnetic core 5. The transmitting coil 1, the compensating coil 3 and the receiving coil 4 are all composed of two anisotropic wound circular coils connected in series, and the two circular coils are in the same horizontal plane. In particular, the two circular coils in the transmitting coil 1 and the compensating coil 3 are wound by a wire. The transmitting end magnetic core 2 is laid flat below the transmitting coil 1 and is arranged close to the transmitting coil 1, and the transmitting end magnetic core 2 completely covers the area of ​​the transmitting coil 1; the compensating coil 3 is placed directly above the transmitting coil 1; the receiving coil 4 is placed directly above the compensating coil 3 of the transmitting end, and is used to couple with the transmitting coil 1 to realize wireless charging; the receiving end magnetic core 5 is laid flat above the receiving coil 4 and is arranged close to the receiving coil 4, and the receiving end magnetic core completely covers the area of ​​the receiving coil 4. The central axis of the transmitting coil 1, the central axis of the compensating coil 3 and the central axis of the receiving coil 4 are coaxially arranged, which is the optimal alignment position, and the wireless charging efficiency is the highest at this time. The transmitting end magnetic core 2 and the receiving end magnetic core 5 are both made of rectangular ferrite material.

[0032] In the existing wireless charging magnetic coupling mechanism, the magnetic flux density is the largest when the transmitting coil is directly above the center, and the coupling with the receiving coil is also the strongest. As the coil deviates, the magnetic flux density decreases and the coupling gradually decreases. Therefore, in general, the mutual inductance is the highest when the coils are directly opposite, and as the coil offset gradually increases, the mutual inductance of the coupling mechanism gradually decreases. The compensation coil 3 in this scheme can offset part of the magnetic flux directly above the center, reduce the magnetic flux density at the center, and reduce the magnetic flux coupling when the coupling mechanism is directly opposite, so that the degree of magnetic flux coupling is similar to that in the offset situation, so that the mutual inductance before and after the offset is similar. Under ideal conditions, within a certain offset range, the mutual inductance does not change with the increase of the offset, and the mutual inductance offset curve remains horizontal.

[0033] like Figure 2 As shown, compared Figure 2 It can be seen from (a) and (b) that the magnetic field intensity directly above the transmitting coil 1 is relatively high when the compensation coil 3 is not added, and the magnetic field intensity directly above the transmitting coil 1 is significantly reduced after the compensation coil 3 is added. Therefore, the mutual inductance when the coupling mechanism is facing each other will also be reduced, and will be closer to the mutual inductance of the coupling mechanism after the coil is offset, thereby making the mutual inductance offset curve smoother, which proves the anti-offset ability of the present invention.

[0034] like Figure 3As shown, when the coils are facing each other, the mutual inductance of the coupling mechanism is the highest. When an offset occurs, the mutual inductance gradually decreases overall. However, since the magnetic coupling mechanism proposed in the present invention has good anti-offset performance, the offset curve is relatively stable, and the X-axis anti-offset performance is better than the Y-axis, which shows that the present invention has good anti-offset performance.

[0035] like Figure 4 As shown, compared Figure 4 (a) and Figure 4 (b) It can be seen that after adding the compensation coil, the waveform of the coupling mechanism changes smoothly during the continuous offset process, and is almost consistent before and after the offset, which proves that the coupling mechanism proposed in the present invention has a high anti-offset performance. The specific parameter values ​​are as follows: the input voltage is 20V, the resonant frequency is uniformly set to 190kHz, the load is set to 24Ω, the number of turns of the offset coil is 7 turns, the radius is 103mm, the number of turns of the transmitting coil is 10 turns, the radius is 205mm, the number of turns of the receiving coil is 20 turns, the radius is 109mm, where Figure 4 (a) is the experimental waveform diagram during the offset process without adding the compensation coil (after the Y-axis direction offsets 100mm, the X-axis direction continues to offset 100mm), and the transmission distance is 150mm; Figure 4 (b) is the experimental waveform diagram during the offset process after adding the compensation coil (after offsetting 100mm in the Y-axis direction, the X-axis direction continues to offset 100mm). The distance between the transmitting coil and the receiving coil is 150mm, and the distance between the offset coil and the transmitting coil is 45mm. Figure 4 Middle,U s -Primary voltage, U out -output voltage, I1-primary current, I2-output current.

[0036] like Figure 5 As shown, the present invention also includes a design method for a stacked high-capacitance magnetic coupling mechanism based on anisotropically wound coils, comprising the following steps:

[0037] (i) Determine the size, number of turns and transmission height of the original transmitting coil and receiving coil, where the compensation coil radius R3=a, the number of turns of the compensation coil N3=1, and the transmission height h1=h;

[0038] (ii) Setting the minimum values ​​of the compensation coil structural parameters and the initial value of the transmission height;

[0039] (iii) setting the X and Y axis offset ranges, dividing the maximum offset distance into N intervals;

[0040] (iv) Set the initial values ​​x1 and x2 of the minimum and maximum offset tolerances in the X-axis offset direction, set the initial values ​​x3 and x4 of the minimum and maximum offset tolerances in the Y-axis offset direction, and set the original mutual inductance M tr1 The initial proportion of holdings a;

[0041] (V) Calculate the mutual inductance value M corresponding to the right endpoint value of the i-th interval in the X-axis offset direction i ; Calculate the mutual inductance value M corresponding to the right endpoint value of the i-th interval in the Y-axis offset direction j ; Where i,j=1,2,…,N;

[0042] (VI) Setting constraints, if the mutual inductance value M i and M j If the constraints are met, the compensation coil center radius R3, number of turns N3, and transmission height h1 are output.

[0043] The constraints set are:

[0044]

[0045] Where x1 and x2 are the initial values ​​of the minimum and maximum offset tolerance in the X-axis offset direction, respectively; x3 and x4 are the initial values ​​of the minimum and maximum offset tolerance in the Y-axis offset direction, respectively; σ i and σ j are the offset tolerance of each segmented test point on the X-axis and Y-axis respectively; M0 is the mutual inductance when the coupling mechanism is facing each other; M i and M j are the mutual inductance values ​​of each segmented test point on the X-axis and Y-axis after compensation; where i,j=1,2,…,N.

[0046] In step (six), if the mutual inductance value M i and M j If the constraint condition is not met, the value of the compensation coil radius R3 is adjusted according to the formula R3=R3+ΔR3, where ΔR3=1mm, and it is determined whether the adjusted compensation coil radius R3 is not greater than the specified transmitting end size.

[0047] If the adjusted value of the compensation coil radius R3 satisfies the requirement of not being greater than the specified transmitting end size, proceed to step (five); if the adjusted value of the compensation coil radius R3 does not satisfy the requirement of not being greater than the specified transmitting end size, adjust the value of the transmission height h1 according to the formula R3=a, h1=h1+Δh1, where Δh1=1mm, and determine whether the adjusted value of the transmission height h1 satisfies the requirement of not being less than the set transmission gap.

[0048] If the adjusted transmission height h1 value does not meet the requirement of being not less than the set transmission gap, increase the number of turns of the compensation coil; determine whether the transmitting end meets the requirement of being not greater than the specified size after the number of turns of the compensation coil is increased. If not, proceed to step (iv).

Claims

1. A design method for a stacked high-capacitance magnetic coupling mechanism based on anisotropically wound coils, characterized in that: The method is applied to a stacked high-capacitance-rate magnetic coupling mechanism based on anisotropically wound coils. The stacked high-capacitance-rate magnetic coupling mechanism based on anisotropically wound coils comprises a transmitting end and a receiving end; the transmitting end comprises a transmitting coil (1), a transmitting end magnetic core (2) and a compensation coil (3); the transmitting end magnetic core (2) is laid flat below the transmitting coil (1) and is arranged close to the transmitting coil (1); the compensation coil (3) is placed directly above the transmitting coil (1); The receiving end comprises a receiving coil (4) and a receiving end magnetic core (5); the receiving coil (4) is placed directly above the compensation coil (3) of the transmitting end and is used to couple with the transmitting coil (1) to achieve wireless charging; the receiving end magnetic core (5) is laid flat above the receiving coil (4) and is arranged close to the receiving coil (4); the transmitting coil (1), the compensation coil (3) and the receiving coil (4) are formed by two coils wound in opposite directions connected in series; The design method of the stacked high-capacitance-bias magnetic coupling mechanism based on anisotropically wound coils comprises the following steps: (i) Determine the size, number of turns and transmission height of the original transmitting coil and receiving coil, where the compensation coil radius R3=a, the number of turns of the compensation coil N3=1, and the transmission height h1=h; (ii) Setting the minimum values ​​of the compensation coil structural parameters and the initial value of the transmission height; (iii) setting the X and Y axis offset ranges, dividing the maximum offset distance into N intervals; (iv) Set the initial values ​​x1 and x2 of the minimum and maximum offset tolerances in the X-axis offset direction, set the initial values ​​x3 and x4 of the minimum and maximum offset tolerances in the Y-axis offset direction, and set the original mutual inductance M tr1 The initial proportion of holdings a; (V) Calculate the mutual inductance value M corresponding to the right endpoint value of the i-th interval in the X-axis offset direction i ; Calculate the mutual inductance value M corresponding to the right endpoint value of the i-th interval in the Y-axis offset direction j ; Where i,j=1,2,…,N; (VI) Setting constraints, if the mutual inductance value M i and M j If the constraints are met, the compensation coil center radius R3, number of turns N3, and transmission height h1 are output; In step (six), if the mutual inductance value M i and M j If the constraint condition is not met, the value of the compensation coil radius R3 is adjusted according to the formula R3=R3+ΔR3, where ΔR3=1mm, and it is determined whether the adjusted compensation coil radius R3 is not greater than the specified transmitting end size; The constraints set are: Where x1 and x2 are the initial values ​​of the minimum and maximum offset tolerance in the X-axis offset direction, respectively; x3 and x4 are the initial values ​​of the minimum and maximum offset tolerance in the Y-axis offset direction, respectively; σ i and σ j are the offset tolerance of each segmented test point on the X-axis and Y-axis respectively; M0 is the mutual inductance when the coupling mechanism is facing each other; M i and M j are the mutual inductance values ​​of each segmented test point on the X-axis and Y-axis after compensation; where i,j=1,2,…,N.

2. The design method of the stacked high-capacitance-bias magnetic coupling mechanism based on anisotropically wound coils according to claim 1 is characterized in that: The central axis of the transmitting coil (1), the central axis of the compensating coil (3), and the central axis of the receiving coil (4) are coaxially arranged.

3. The design method of the stacked high capacitance ratio magnetic coupling mechanism based on the anisotropically wound coils according to claim 1 is characterized by: The transmitting coil (1) and the compensating coil (3) are wound using the same wire.

4. The design method of the stacked high capacitance ratio magnetic coupling mechanism based on the anisotropically wound coils according to claim 1 is characterized in that: The transmitting end magnetic core (2) and the receiving end magnetic core (5) are both made of rectangular ferrite material.

5. The design method of the stacked high capacitance ratio magnetic coupling mechanism based on the anisotropically wound coils according to claim 1 is characterized by: If the adjusted value of the compensation coil radius R3 is not greater than the specified transmitting end size, proceed to step (V).

6. The design method of the stacked high capacitance ratio magnetic coupling mechanism based on the anisotropically wound coils according to claim 1 is characterized by: If the adjusted value of the compensation coil radius R3 does not meet the requirement of being no greater than the specified transmitting end size, the value of the transmission height h1 is adjusted according to the formula R3=a, h1=h1+Δh1, where Δh1=1mm, and it is determined whether the adjusted value of the transmission height h1 meets the requirement of being no less than the set transmission gap.

7. The design method of the stacked high capacitance ratio magnetic coupling mechanism based on the anisotropically wound coils according to claim 6 is characterized by: If the adjusted transmission height h1 value does not meet the requirement of being not less than the set transmission gap, increase the number of turns of the compensation coil; determine whether the transmitting end meets the requirement of being not greater than the specified size after the number of turns of the compensation coil is increased. If not, proceed to step (iv).

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