Wireless power transmission system and parameter design method

Abstract

The invention discloses a wireless power transmission system and a parameter design method, and belongs to the technical field of wireless power transmission. The invention aims to solve the problem that the anti-offset capability of a DD type coil of a magnetic coupling mechanism in a wireless power transmission system along the orthogonal axis direction is poor. The wireless electric energy transmission system comprises an inverter, a magnetic coupling mechanism and a rectifier. Secondary side coils of the magnetic coupling mechanism are double receiving coils, the double receiving coils are connected in series through unlike terminals, and a midpoint tap is led out from the middle of the double receiving coils; the rectifier is connected with the midpoint tap through the decoupling capacitor CM. The method is used for improving the anti-offset capability of the wireless power transmission system.

Description

Technical Field

[0001] The present invention relates to a wireless power transmission system and a parameter design method, and belongs to the technical field of wireless power transmission. Background Art

[0002] In recent years, continuous innovation in power electronics technology has fundamentally altered traditional models of electricity production, transmission, and use, bringing about a new revolution in the energy sector. Wireless power transfer (WPT), with its contactless power transmission capabilities, breaks through the physical constraints of traditional cables. Its convenience, safety, low maintenance costs, and strong environmental adaptability have shown tremendous application potential in a variety of fields, including electric vehicles, consumer electronics, implantable medical devices, and underwater unmanned vehicles. Among them, electromagnetic induction wireless power transfer is the most mature and widely used wireless power supply method.

[0003] Energy transmission relies on the principle of electromagnetic induction. In practical applications, the primary and secondary coils of a magnetic coupling mechanism inevitably deviate from each other, causing a decrease in the coupling coefficient and impacting system operation. To improve the system's deflection resistance, multipolar magnetic field coils, such as the most common DD coil, are used. However, the DD coil structure exhibits strong deflection resistance only along the horizontal axis (y-axis). Its mutual inductance decreases significantly when deflected along the orthogonal axis (x-axis), resulting in large power fluctuations. Furthermore, when the DD coil deviates along the x-axis, the coupling crosses zero, causing the system to fail to transmit energy. For WPT systems with constant current output, when the coupling crosses zero, the transmitter power may even surge, potentially damaging the circuit. To address the large mutual inductance fluctuations, decoupled dual receiving coils, such as DDQ and BP coils, are used. These coils prevent mutual interference and avoid the introduction of reactive power due to cross-coupling. This dual-coil structure typically requires two separate rectifiers, which are then connected in series or parallel. However, the magnetic decoupling design of BP and DDQ coils imposes strict restrictions on the coil geometry.

[0004] In addition, polarized and non-polarized coils have interoperability issues because they decouple from each other when aligned and cannot transfer energy, such as square coils and DD coils, which limits the versatility and compatibility of chargers and receivers, such as Figure 1 shown. Summary of the Invention

[0005] To address the problem that a DD-type coil of a magnetic coupling mechanism in a wireless power transmission system has poor anti-deviating capability along the orthogonal axis direction, the present invention provides a wireless power transmission system and a parameter design method.

[0006] A wireless power transmission system of the present invention includes an inverter, a magnetic coupling mechanism, and a rectifier; the secondary coil of the magnetic coupling mechanism is a dual receiving coil, the dual receiving coils are connected in series through opposite-name terminals, and a midpoint tap is drawn from the middle of the dual receiving coils;

[0007] The rectifier is decoupled through the capacitor C M Connect to the midpoint tap.

[0008] According to the wireless power transmission system of the present invention, the secondary structure of the magnetic coupling mechanism includes a receiving coil L S1 , receiving coil L S2 , compensation capacitor C S1 and compensation capacitor C S2 ;

[0009] Receiving coil L S1 The opposite end is connected to the receiving coil L S2 The opposite end of the receiving coil L S1 and receiving coil L S2 A midpoint tap is drawn between the two terminals for connecting to a rectifier;

[0010] Receiving coil L S1 The same-name terminal is connected to the compensation capacitor C S1 One end of the compensation capacitor C S1 The other end of the receiving coil L S2 The same-name terminal is connected to the compensation capacitor C S2 One end of the compensation capacitor C S2 The other end is used as the connection end of the rectifier.

[0011] According to the wireless power transmission system of the present invention, the rectifier includes a decoupling capacitor C M , diode D1, diode D2, diode D3, diode D4, filter capacitor C F1 and filter capacitor C F2 ;

[0012] The anode of diode D1 is connected to the cathode of diode D2, the anode of diode D2 is connected to the cathode of diode D3, the anode of diode D3 is connected to the cathode of diode D4, and the anode of diode D4 is connected to the filter capacitor C. F2 The positive pole of the filter capacitor C F2 The negative pole of the filter capacitor C is connected F1 The positive pole of the filter capacitor C F1 The negative electrode of the filter capacitor C is connected to the cathode of the diode D1; F1 The negative electrode and filter capacitor C F2 Connect a load resistor R between the positive terminals of L ;

[0013] Compensation capacitor CS1 The other end is connected to the anode of diode D1; compensation capacitor C S2 The other end is connected to the anode of diode D3;

[0014] The midpoint tap is connected to the decoupling capacitor C M One end of the decoupling capacitor C M The other end is connected to the anode of diode D2 and the filter capacitor C F1 positive electrode.

[0015] The present invention also provides a parameter design method for a wireless power transmission system, which is used to design parameters of the wireless power transmission system, including designing a decoupling capacitor C M Method:

[0016] Obtain the controlled source equivalent model diagram of the magnetic coupling mechanism, based on the T equivalent theory of mutual inductance, the receiving coil L S1 and receiving coil L S2 Mutual inductance M S1S2 Through the decoupling capacitor C M To make compensation:

[0017]

[0018] Where ω is the resonant angular frequency.

[0019] According to the parameter design method of the wireless power transmission system of the present invention, the compensation capacitor C S1 and compensation capacitor C S2 Design method:

[0020]

[0021] Where L S1 ' is the receiving coil L in the equivalent model diagram of the controlled source of the magnetic coupling mechanism S1 The equivalent inductance, L S2 ' is the receiving coil L in the equivalent model diagram of the controlled source of the magnetic coupling mechanism S2 The equivalent inductance of

[0022]

[0023] Beneficial effects of the present invention: The present invention proposes a wireless power transmission system with strong anti-offset capability and interoperability, and designs a new rectifier series circuit, which is suitable for dual receiving coils that do not need to be decoupled from each other and has a high degree of design freedom. For the most commonly used DD coil, the secondary DD coil is divided into two sections, and the midpoint tap is connected in series with a capacitor to achieve a magnetic decoupling effect. Without affecting the efficiency of the system, the present invention realizes the summation of the absolute values of the mutual inductance on the primary and secondary sides, thereby improving the fluctuation of the equivalent mutual inductance curve in the x-axis direction and improving the anti-offset capability of the system. At the same time, the present invention has the characteristics of self-adaptation for different types of dual receiving coils. This method improves the interoperability of the system and can be effectively compatible with DD coils and square coils at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the interoperability of the primary and secondary coils of the magnetic coupling mechanism;

[0025] Figure 2 This is a schematic diagram of the circuit structure of the wireless power transmission system of the present invention; is the inverter output voltage, is the inverter output current, The receiving coil L S1 The current, The receiving coil L S2 The current, for The corresponding rectifier input voltage, for The corresponding rectifier input voltage;

[0026] Figure 3 It is the controlled source equivalent model diagram of the magnetic coupling mechanism;

[0027] Figure 4 This is the equivalent model diagram of the controlled source when the rectifier input currents are in phase;

[0028] Figure 5 This is the equivalent model diagram of the controlled source when the rectifier input current is reversed;

[0029] Figure 6 It is a schematic diagram of the rectifier and diode current waveforms in the same phase state;

[0030] Figure 7 It is a schematic diagram of the rectifier and diode current waveforms in the reverse state;

[0031] Figure 8 The decoupling capacitor C M Schematic diagram of the first circuit structure achieved by splitting into three branches;

[0032] Figure 9The decoupling capacitor C M Schematic diagram of the second circuit structure realized by splitting into three branches;

[0033] Figure 10 The decoupling capacitor C M Schematic diagram of the third circuit structure realized by splitting into three branches;

[0034] Figure 11 The decoupling capacitor C M Schematic diagram of the fourth circuit structure realized by splitting into three branches;

[0035] Figure 12 The decoupling capacitor C M Schematic diagram of the fifth circuit structure realized by splitting into three branches;

[0036] Figure 13 The decoupling capacitor C M Schematic diagram of the sixth circuit structure realized by splitting into three branches;

[0037] Figure 14 It is a schematic diagram of the primary and secondary DD coils of the magnetic coupling mechanism;

[0038] Figure 15 This is the equivalent circuit diagram of the wireless power transmission system using the traditional DD coil;

[0039] Figure 16 2. It is a schematic diagram of a curve showing a change in mutual inductance of the wireless power transmission system according to the present invention with respect to an offset distance;

[0040] Figure 17 Schematic diagram of a WPT system prototype in the embodiment;

[0041] Figure 18 Schematic diagram of output voltage and efficiency curves when the primary and secondary coils of the WPT system are aligned in the embodiment;

[0042] Figure 19 2 is a schematic diagram of an output voltage curve when the primary and secondary coils of the WPT system are offset in the embodiment; in the figure, x-axis represents the x-axis, and y-axis represents the y-axis;

[0043] Figure 20 The following are experimental waveforms of inverter voltage and current under four offset and load conditions;

[0044] Figure 21 The following are experimental waveforms of the rectifier voltage and current under various offset conditions when the load is 40Ω. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0047] The present invention will be further described below with reference to the accompanying drawings, but is not intended to limit the present invention.

[0048] Specific implementation method 1. Combination Figure 2 As shown, the present invention provides a wireless power transmission system, including an inverter, a magnetic coupling mechanism and a rectifier;

[0049] The secondary coil of the magnetic coupling mechanism is a double receiving coil, the double receiving coils are connected in series through opposite-name terminals, and a midpoint tap is drawn out from the middle of the double receiving coils;

[0050] The rectifier is decoupled through the capacitor C M Connect to the midpoint tap.

[0051] Combine Figure 2 The following is a circuit diagram of a WPT system with LCC / S compensation topology, dual receiving coils and a new rectifier. in and i in is the inverter output voltage and current; L f1 , C f1 , C P1 , C S1 , C S2 is the compensation inductance and capacitance; L P is the self-inductance of the primary coil; L S1 and L S2 is the self-inductance of the secondary coil; M PS1 , M PS2 , M S1S2 L P With L S1 , L P With L S2 , L S1 With L S2 Mutual inductance between M is a decoupling capacitor; D1~D4 are rectifier diodes; C F1 and C F2 is the filter capacitor; R L is the load resistance; U ois the DC output voltage; u re1 ,u re2 ,i re1 ,i re2 are the rectifier input voltage and current. A and B are the inverter output terminals.

[0052] Furthermore, the secondary side structure of the magnetic coupling mechanism includes a receiving coil L S1 , receiving coil L S2 , compensation capacitor C S1 and compensation capacitor C S2 ;

[0053] Receiving coil L S1 The opposite end is connected to the receiving coil L S2 The opposite end of the receiving coil L S1 and receiving coil L S2 A midpoint tap is drawn between the two terminals for connecting to a rectifier;

[0054] Receiving coil L S1 The same-name terminal is connected to the compensation capacitor C S1 One end of the compensation capacitor C S1 The other end of the receiving coil L S2 The same-name terminal is connected to the compensation capacitor C S2 One end of the compensation capacitor C S2 The other end is used as the connection end of the rectifier.

[0055] The rectifier includes a decoupling capacitor C M , diode D1, diode D2, diode D3, diode D4, filter capacitor C F1 and filter capacitor C F2 ;

[0056] The anode of diode D1 is connected to the cathode of diode D2, the anode of diode D2 is connected to the cathode of diode D3, the anode of diode D3 is connected to the cathode of diode D4, and the anode of diode D4 is connected to the filter capacitor C. F2 The positive pole of the filter capacitor C F2 The negative pole of the filter capacitor C is connected F1 The positive pole of the filter capacitor C F1 The negative electrode of the filter capacitor C is connected to the cathode of the diode D1; F1 The negative electrode and filter capacitor C F2 Connect a load resistor R between the positive terminals of L ;

[0057] Compensation capacitor C S1 The other end is connected to the anode of diode D1; compensation capacitor C S2 The other end is connected to the anode of diode D3;

[0058] The midpoint tap is connected to the decoupling capacitor C M One end of the decoupling capacitor C M The other end is connected to the anode of diode D2 and the filter capacitor C F1 positive electrode.

[0059] Specific implementation method 2: Figure 2 and Figure 3 As shown, the present invention also provides a parameter design method for a wireless power transmission system, which is used to design parameters of the wireless power transmission system described in the first embodiment, including designing a decoupling capacitor C M Method:

[0060] The equivalent model diagram of the controlled source of the magnetic coupling mechanism is as follows: Figure 3 As shown, based on the T equivalent theory of mutual inductance, the receiving coil L S1 and receiving coil L S2 Mutual inductance M S1S2 Through the decoupling capacitor C M To make compensation:

[0061]

[0062] Where ω is the resonant angular frequency.

[0063] Also includes compensation capacitor C S1 and compensation capacitor C S2 Design method:

[0064]

[0065] Where L S1 ' is the receiving coil L in the equivalent model diagram of the controlled source of the magnetic coupling mechanism S1 The equivalent inductance, L S2 ' is the receiving coil L in the equivalent model diagram of the controlled source of the magnetic coupling mechanism S2 The equivalent inductance of

[0066]

[0067] The compensation parameter design method of this implementation is the same as that of the traditional LCC / S compensation topology:

[0068]

[0069] Combine Figure 4 and Figure 5 Perform modal analysis on the rectifier. When M PS1 ·M PS2 >0, the rectifier input current is in phase, when M PS1 ·M PS2<0, the rectifier input current is in reverse phase. It is worth mentioning that the voltage and current reference phases are defined based on the positive mutual inductance. For example, Figure 4 and Figure 5 The corresponding cases in M are PS1 >0,M PS2 >0 and M PS1 >0,M PS2 <0.

[0070] There are two operating states in one cycle, such as the same phase, Figure 6 shown, including:

[0071] [State I]: During t0~t1, D1 is on, and C F1 and R L Power supply, D3 is turned on and continues current flow.

[0072] [State II]: During t1~t2, D2 is conducting and the current continues to flow, D4 is conducting, and the current is C F2 and R L powered by.

[0073] The situation of current reversal is similar, such as Figure 7 As shown, no further details are given.

[0074] Since the filter capacitor C F1 and C F2 The output voltage U o It is equivalent to the sum of the output DC voltages of the two half-bridge rectifiers, so the output voltage U o Satisfies the following formula:

[0075]

[0076] The equivalent load R of the half-bridge rectifier re It can be obtained by combining the power conservation principle with the series relationship:

[0077]

[0078] From the output voltage U o In the figure, the total equivalent mutual inductance M of the primary and secondary sides is PS The following formula is satisfied, which is essentially the sum of the absolute values of all mutual inductances between the primary and secondary sides:

[0079] M PS =|M PS1 |+|M PS2 |.

[0080] Apart from Figure 2 In the circuit topology, the capacitor C M Can be split into 3 branches, namely C M1 , C M2 , CM3 , respectively connected to the midpoints of D2 and D3, the cathode of D1 and the anode of D4, the same characteristics can be achieved, such as Figures 8 to 13 Among them, one or two of the three branches can be removed at will, so the total is This circuit, as long as the sum of the capacitance of each branch is equal to C M The specific working mode will not be described in detail.

[0081] Verification experiment: The rectifier designed by the present invention is particularly suitable for DD coils. Figure 14 For example, the primary and secondary coils have the same external dimensions, and their turns are 12 and 11 respectively. The secondary DD coil is divided into two D coils. The traditional DD coil is equivalent to two coils connected in series in the forward direction. In the traditional DD structure, the mutual inductance M PS and self-sensing L S Satisfies the following formula:

[0082] M PS =M PS1 +M PS2 ,

[0083] L S =L S1 +L S2 +2M S1S2 .

[0084] In fact, when the secondary coil is changed to the traditional DD coil, Figure 2 The circuit can be connected with Figure 15 The circuit is equivalent. When |M PS1 +M PS2 |=|M PS1 |+|M PS2 |, both topologies have the same output voltage under load, which means that both rectifiers have the same losses at the same output power. In addition, Figure 2 and Figure 15 The rectifier has the same losses as a normal full-bridge rectifier at the same output power, and they have the same number of diodes.

[0085] When the transmission distance is 9.5 cm, the curves of mutual inductance and x-axis and y-axis offset can be obtained, such as Figure 16As shown. Since the coil is a centrally symmetrical structure, only the cases of x>0 and y>0 are shown. According to formulas (6) and (7), comparing the mutual inductance curves, the proposed structure has a stronger anti-offset capability in the x-axis. Although the mutual inductance curves of the traditional structure and the proposed structure are the same in the y-axis offset, the DD coil itself has a stronger anti-offset capability in the y-axis. According to the calculation formulas of the mutual inductance in the two cases, comparing the mutual inductance curves, the structure proposed by the present invention has a stronger anti-offset capability in the x-axis. Although the mutual inductance curves of the traditional structure and the structure of the present invention are the same in the y-axis offset, the DD coil itself has a stronger anti-offset capability in the y-axis.

[0086] In fact, when M PS1 ·M PS2 <0, the structure proposed in the present invention can realize the automatic switching of the secondary coil from DD to square coil. This improves the disadvantage of DD coil, that is, the poor anti-offset capability in the x-axis direction. Figure 16 As shown, the equivalent mutual inductance is reduced by 29.1%, while the traditional structure has a mutual inductance zero crossing point.

[0087] Example:

[0088] In order to verify the anti-drift capability of the structure of the present invention, a 1kW experimental prototype with DD coil and LCC / S compensation topology was constructed. Figure 17 As shown, the secondary DD coil is divided into two coils and connected to the new rectifier. The circuit diagram is as follows Figure 2 The WPT system circuit parameters are shown in Table 1. The inverter frequency f is 82kHz.

[0089] Table 1 Circuit parameters

[0090]

[0091] When the coils are aligned, the output voltage and efficiency curves are as follows: Figure 18 As shown in the figure, within a 10-fold load variation range, the output voltage rises from 200V to 216.5V with a fluctuation rate of 8.2% and a maximum efficiency of 91.3%.

[0092] The output voltage curve of the coil offset is as follows Figure 19 As shown in the figure, using a rated load of 1kW as a reference, the system exhibits strong offset resistance in the y-axis direction, with a maximum voltage drop of 41.2% within a 50% offset of the coil's y-axis length. In the x-axis, offset resistance is also enhanced, with a maximum voltage drop of 68.5% within a 72% offset of the coil's x-axis length. Zero output voltage does not occur, indicating that the primary and secondary equivalent mutual inductance does not reach zero.

[0093] When the coil is offset, it exhibits a constant voltage output characteristic that is independent of the load. When the load changes from 40Ω to 400Ω, the voltage fluctuation rate is the largest at 8.2% under the coil alignment condition. This is because the power variation is the largest at this time, resulting in a larger voltage drop across the coil's parasitic resistance, and therefore greater output voltage fluctuation.

[0094] The experimental waveforms of the inverter voltage and current under various offset and load conditions are as follows: Figure 20 In all cases, the inverter consistently achieves zero voltage switching (ZVS).

[0095] When the load is 40Ω, the experimental waveforms of the rectifier voltage and current under various offset conditions are as follows Figure 21 As shown. When x = 10cm, the current i re1 and i re2 is inversely proportional to the phase, while in other cases it is in phase, which verifies the above theoretical analysis. The total mutual inductance between the primary and secondary sides is equal to M PS1 and M PS2 The sum of the absolute values of .

[0096] It is worth noting that although Figure 19 The output voltage variation in the rectifier looks significant, but this is mainly due to the design of the DD coil size. The present invention only selects a specific size of DD coil to verify the performance of the rectifier.

[0097] In fact, this method is not limited to DD coils, but can also be extended to other dual-receiver coil structures, such as BP and DDQ coils. By optimizing the design of the mutual inductance curve, a coupling-independent constant voltage output can be effectively achieved.

[0098] Since the equivalent mutual inductance is the sum of absolute values, the present invention effectively solves the zero-crossing problem in bipolar coil coupling, realizes automatic polarity adaptation of the coils, and improves the operability, compatibility and adaptability between coils.

[0099] Eliminating the zero crossings in coupling also improves the safety of WPT systems. In constant current output systems, such as S / S compensation, zero crossings in coupling can cause power surges that can damage the system.

[0100] In summary, the secondary DD coil is center-tapped and connected in series with a capacitor to achieve magnetic decoupling. This structure is then connected to a novel rectifier topology, which makes it possible to sum the absolute value of the mutual inductance of the two parts of the DD coil relative to the primary coil. As a result, the anti-offset capability along the x-axis is significantly enhanced, and automatic switching of the DD coil to a square coil can also be achieved. The rectifier proposed in the present invention uses the same number of diodes as a conventional full-bridge rectifier and maintains the same efficiency. In a 1kW experimental prototype, the results showed that even at an offset distance of 72% relative to the x-axis length of the coil, the output voltage remained at no less than 31.5% of the rated value, and there was no zero crossing in the equivalent mutual inductance.

[0101] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in conjunction with other described embodiments.

Claims

1. A wireless power transmission system comprising an inverter, a magnetic coupling mechanism, and a rectifier; characterized in that: The secondary coil of the magnetic coupling mechanism is a double receiving coil, the double receiving coils are connected in series through opposite-name terminals, and a midpoint tap is drawn out from the middle of the double receiving coils; The rectifier is decoupled through the capacitor C M Connect to the midpoint tap.

2. The wireless power transmission system according to claim 1, wherein: The secondary side structure of the magnetic coupling mechanism includes a receiving coil L S1 , receiving coil L S2 , compensation capacitor C S1 and compensation capacitor C S2 ; Receiving coil L S1 The opposite end is connected to the receiving coil L S2 The opposite end of the receiving coil L S1 and receiving coil L S2 A midpoint tap is drawn between the two terminals for connecting to a rectifier; Receiving coil L S1 The same-name terminal is connected to the compensation capacitor C S1 One end of the compensation capacitor C S1 The other end of the receiving coil L S2 The same-name terminal is connected to the compensation capacitor C S2 One end of the compensation capacitor C S2 The other end is used as the connection end of the rectifier.

3. The wireless power transmission system according to claim 2, wherein: The rectifier includes a decoupling capacitor C M , diode D1, diode D2, diode D3, diode D4, filter capacitor C F1 and filter capacitor C F2 ; The anode of diode D1 is connected to the cathode of diode D2, the anode of diode D2 is connected to the cathode of diode D3, the anode of diode D3 is connected to the cathode of diode D4, and the anode of diode D4 is connected to the filter capacitor C. F2 The positive pole of the filter capacitor C F2 The negative pole of the filter capacitor C is connected F1 The positive pole of the filter capacitor C F1 The negative electrode of the filter capacitor C is connected to the cathode of the diode D1; F1 The negative electrode and filter capacitor C F2 Connect a load resistor R between the positive terminals of L ; Compensation capacitor C S1 The other end is connected to the anode of diode D1; compensation capacitor C S2 The other end is connected to the anode of diode D3; The midpoint tap is connected to the decoupling capacitor C M One end of the decoupling capacitor C M The other end is connected to the anode of diode D2 and the filter capacitor C F1 positive electrode.

4. A parameter design method for a wireless power transmission system, used for parameter design of the wireless power transmission system according to claim 3, characterized in that Including design of decoupling capacitor C M Method: Obtain the controlled source equivalent model diagram of the magnetic coupling mechanism, based on the T equivalent theory of mutual inductance, the receiving coil L S1 and receiving coil L S2 Mutual inductance M S1S2 Through the decoupling capacitor C M To make compensation: Where ω is the resonant angular frequency.

5. The parameter design method of the wireless power transmission system according to claim 4, characterized in that Also includes compensation capacitor C S1 and compensation capacitor C S2 Design method: Where L S1 ' is the receiving coil L in the equivalent model diagram of the controlled source of the magnetic coupling mechanism S1 The equivalent inductance, L S2 ' is the receiving coil L in the equivalent model diagram of the controlled source of the magnetic coupling mechanism S2 The equivalent inductance of

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