Dynamic wireless power supply system based on double receiving coil and current doubling rectifier

Abstract

The application provides a kind of dynamic wireless power supply system based on double receiving coil and current doubling rectifier, including transmitting end and receiving end, characterized in that: transmitting end is provided with segmented transmitting coil along the moving path of receiving end, and receiving end is provided with two receiving coils side by side along the moving direction, each receiving coil is connected to the corresponding current doubling rectifier input group through the corresponding secondary side resonance compensation circuit, filter capacitor and power load are connected on the output group of current doubling rectifier, and the transmitting end changes the opening and closing state of the corresponding energy switching switch according to the position of the receiving end in the same moment only with the adjacent two transmitting coils energized at the same time. The effect is: it can effectively maintain the stability of the output power of the dynamic wireless power supply system during the movement of the receiving end, without complex closed-loop control means, and can reduce the laying cost of the segmented transmitting coil, with good applicability.

Description

Technical Field

[0001] This invention relates to wireless power supply technology, specifically to a dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier. Background Technology

[0002] Wireless Power Transfer (WPT), also known as wireless power transmission or contactless power transfer, refers to the process of converting electrical energy into other forms of relay energy (such as electromagnetic field energy, laser, microwave, and mechanical waves) through a transmitter, transmitting it over a distance, and then converting the relay energy back into electrical energy through a receiver. Due to limitations in energy and environmental pollution, battery capacity, and charging infrastructure, charging has become the biggest bottleneck in the development of electric vehicles. Both wired charging and static wireless charging technologies suffer from frequent charging, short driving range, large battery consumption, and high costs. Therefore, the development of dynamic wireless power transfer technology is increasingly urgent.

[0003] In current low-voltage, high-current wireless power supply systems, the large current at the energy receiving side causes problems such as device overheating and coil losses, affecting the efficient operation of the system. In dynamic wireless power supply systems, the mutual inductance between the transmitting and receiving coils fluctuates due to changes in their relative positions, leading to significant variations in the system's output current. This greatly impacts the safe and reliable operation of the receiving equipment. Therefore, low-voltage, high-current dynamic wireless power supply systems urgently need a solution to address the problem of significant output current fluctuations during receiver movement. Summary of the Invention

[0004] In view of this, the present invention proposes a dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier. This system can effectively maintain the stability of the output power of the dynamic wireless power supply system during the movement of the receiving end, without the need for complex closed-loop control methods, and can reduce the laying cost of segmented transmitting coils.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier includes a transmitter and a receiver. The key features are: the transmitter has segmented transmitting coils arranged along the moving path of the receiver; each segment of the transmitting coil is connected to an AC bus via a corresponding primary-side resonant compensation network and a corresponding energy switching switch; the front end of the AC bus is connected to a DC power supply via a high-frequency inverter; the receiver has two receiving coils arranged side-by-side along the moving direction; each receiving coil is connected to a corresponding current multiplier rectifier input group via a corresponding secondary-side resonant compensation circuit; a filter capacitor and a load are connected to the output group of the current multiplier rectifier; the transmitter, based on the position of the receiver, sequentially changes the opening and closing state of the corresponding energy switching switch in a manner where only two adjacent transmitting coils are energized simultaneously.

[0007] Optionally, both the primary-side resonant compensation circuit and the secondary-side resonant compensation circuit are LCC compensation circuits.

[0008] Optionally, both the transmitting coil and the receiving coil are rectangular planar coils, and the transmitting coil and the receiving coil have the same dimensions in the width direction.

[0009] Optionally, a coil gap is reserved between two adjacent transmitting coil sections.

[0010] Optionally, the current-doubling rectifier circuit includes diodes D1, D2, D3, D4, and an anti-coupling transformer T. Diodes D1, D2, D3, and D4 form a full-bridge rectifier circuit. The two coil windings of the anti-coupling transformer T are connected in series on the two common arms of the full-bridge rectifier circuit. The upper ends of the first and second coil windings of the anti-coupling transformer T serve as the first input terminal group and are connected to the secondary resonant compensation circuit corresponding to the first receiving coil. The lower ends of the first and second coil windings of the anti-coupling transformer T serve as the second input terminal group and are connected to the secondary resonant compensation circuit corresponding to the second receiving coil. The upper ends of the first coil winding and the lower ends of the second coil winding are terminals of the same name.

[0011] Optionally, each segment of the transmitting coil has the same shape and size, and the two receiving coils have the same shape and size, and satisfy the following condition for at least a certain period of time: M 11 +M 12 =M 21 +M 22 ,in:

[0012] M 11 This represents the mutual inductance between the first receiving coil and the first energized transmitting coil;

[0013] M 12This represents the mutual inductance between the first receiving coil and the second energized transmitting coil;

[0014] M 21 This represents the mutual inductance between the second receiving coil and the first energized transmitting coil;

[0015] M 22 This represents the mutual inductance between the second receiving coil and the second energized transmitting coil.

[0016] The effects of this invention are:

[0017] (1) When the dual receiving coils move, the sum of the mutual inductance between one receiving coil and the adjacent segment transmitting coil is always maintained at the rated value, which avoids power fluctuations in the system when crossing the segmented no-power area, thus providing stable power supply to the system.

[0018] (2) The present invention innovatively designs a receiver topology structure with dual receiving coils and current multiplier rectifier, which not only realizes stable power supply of the system, but also achieves automatic switching of working mode when mutual inductance fluctuates without the need to build a complex closed-loop control system, thereby reducing the complexity of the system and making it easier to apply and promote.

[0019] (3) Unlike the traditional method of closely arranging segmented transmitting coils, the coupling mechanism structure of segmented transmitting coils and dual receiving coils proposed in this invention can be designed with a wider spacing between adjacent segmented transmitting coils according to different application scenarios, thereby reducing the amount of wire used in segmented transmitting coils, reducing the construction cost of dynamic wireless power supply system, and at the same time avoiding magnetic field cancellation caused by the reverse current in the width direction due to the excessive proximity of two adjacent transmitting coils. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a circuit diagram of the system in a specific embodiment of the present invention;

[0022] Figure 2 This is an equivalent circuit diagram of the system in a specific embodiment of the present invention;

[0023] Figure 3 The diagram shows the mutual inductance fluctuations of the segmented transmitting coil and dual receiving coils as their positions change;

[0024] Figure 4To simplify the system topology and operating waveforms when the system is operating in mode A;

[0025] Figure 5 The system topology and operating waveforms are simplified when the system is operating in mode B. Detailed Implementation

[0026] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0027] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0028] like Figure 1 and Figure 2 As shown, this embodiment provides a dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier, including a transmitter and a receiver. The transmitter has segmented transmitting coils arranged along the moving path of the receiver, with a coil gap reserved between adjacent transmitting coil segments. Each transmitting coil segment is connected to an AC bus through a corresponding primary-side resonant compensation network and a corresponding energy switching switch. The front end of the AC bus is connected to a DC power supply V through a high-frequency inverter. dc Connection; The high-frequency inverter consists of Q1, Q2, Q3, and Q4. The primary-side resonant compensation network is an LCC compensation circuit. Taking a four-segment coil as an example, the corresponding segmented transmitting coil is L... P1 L P2 L P3 L P4The corresponding energy switching switches are S1, S2, S3, and S4. Two receiving coils, labeled receiving coil #1 and receiving coil #2, are arranged side-by-side along the direction of movement. Each receiving coil is connected to the corresponding input group of a current multiplier rectifier via a corresponding secondary resonant compensation circuit. A filter capacitor and a load are connected to the output group of the current multiplier rectifier. The secondary resonant compensation circuit is also an LCC compensation circuit. The current multiplier rectifier circuit includes diodes D1, D2, D3, and D4, and an anti-coupling transformer T. Diodes D1 and D2... Diodes D3 and D4 form a full-bridge rectifier circuit. The two coil windings of the anti-coupling transformer T are connected in series on the two common arms of the full-bridge rectifier circuit. The upper ends of the first and second coil windings of the anti-coupling transformer T serve as the first input terminal group, connected to the secondary resonant compensation circuit corresponding to the first receiving coil. The lower ends of the first and second coil windings of the anti-coupling transformer T serve as the second input terminal group, connected to the secondary resonant compensation circuit corresponding to the second receiving coil. The upper ends of the first and second coil windings are terminals with the same name. The transmitting end changes the opening and closing state of the corresponding energy switching switch one by one according to the position of the receiving end, in a manner that only two adjacent transmitting coils are energized at the same time.

[0029] In practice, both the transmitting and receiving coils are rectangular planar coils, and their width dimensions are the same. When the receiving end moves on adjacent segmented transmitting coils, energy switching switches S1 and S2 close, and energy flows through the segmented transmitting coil L. P1 and L P2 Transmitted to the receiving end, and L P1 and L P2 The sum of the mutual inductances of receiving coil #1 is M 11 +M 12 L P1 and L P2 The sum of the mutual inductances of receiving coil #2 is M 21 +M 22 If the mutual inductance between the two receiving coils and the segmented transmitting coils is the same, the current multiplier rectifier operates in full-bridge rectifier mode, and the output current is twice the AC output current of a single receiving coil. If the mutual inductance between the two receiving coils and the transmitting coils is different, the current multiplier rectifier uses one of the receiving coils with a larger mutual inductance as the main energy channel (taking receiving coil #2 as an example). Its rectified output current is twice the AC output current of receiving coil #2, while the mutual inductance fluctuation of receiving coil #1 does not affect the stability of the system output current.

[0030] The specific working principle of the above system is analyzed as follows:

[0031] When the dual receiving coils move, to reduce system losses, only the resonant compensation mechanisms of two adjacent segmented transmitting coils are activated at any given time (S1, S2 are activated). According to Kirchhoff's voltage law, the dynamic wireless power supply system at this time can be described as follows:

[0032]

[0033] Where ω is the system's operating angular frequency; M nm The mutual inductance between the receiving coil #n and the segmented transmitting coil #m (n,m=1,2) is represented by the following: The inductance, capacitance, and impedance of the parallel segmented transmitting coil LCC resonant compensation mechanism are respectively expressed as: Z Lri Z Cri Z CPi and Z LPi (i=1,2); The inductance and capacitance impedances of the dual-receiving coil LCC resonant compensation mechanism are respectively expressed as: Z LSi Z CSi Z Cti and Z Lti (i=1,2); and the magnitude of the impedance can be expressed as:

[0034]

[0035] Based on the principle of resonance compensation, when the system operates at the resonant frequency, i.e., when the LCC resonant compensation mechanism satisfies the following relationship, the AC side output current characteristics of the dynamic wireless power supply system can be solved:

[0036]

[0037] By combining equations (1), (2), and (3), the output current i on the AC side of the receiving end can be obtained. t1 with i t2 Constant current output characteristics:

[0038]

[0039] Among them, u P1 This is the output voltage of the high-frequency inverter.

[0040] The operating mode analysis of the low-voltage, high-current dynamic wireless power supply system with dual receiving coils and a current-doubling rectifier is as follows:

[0041] The mutual inductance between the segmented transmitting and receiving coils in a dynamic wireless power supply system is constantly changing. When the dual receiving coils move along the segmented transmitting coils, the change in mutual inductance between the coils can occur in two ways: A. The sum of the mutual inductance between segmented transmitting coils #1,2 and receiving coil #1 equals the sum of the mutual inductance between segmented transmitting coils #1,2 and receiving coil #2; B. The sum of the mutual inductance between segmented transmitting coils #1,2 and receiving coil #1 does not equal the sum of the mutual inductance between segmented transmitting coils #1,2 and receiving coil #2. Therefore, the mutual inductance relationship between the coils can be expressed as:

[0042]

[0043] Among them, M 11 +M 12 M represents the mutual inductance between receiving coil #1 and segmented transmitting coils #1,2. 21 +M 22 This represents the mutual inductance between receiving coil #2 and segmented transmitting coils #1,2; when M 11 +M 12 =M 22 +M 12 When M is in mode A, the system's operating state is defined as mode A; when M is in mode M... 11 +M 12 ≠M 22 +M 12 At that time, the system's operating state is defined as mode B.

[0044] When the system operates in mode A, since the mutual inductance between the receiving coils #1,2 and the segmented transmitting coils #1,2 is equal, the AC output current of the two receiving coils is equal, which can be expressed as:

[0045]

[0046] When the system is operating in the positive half-cycle, the system output current is:

[0047] I out =|i d1 |=|i t1 +i t2 | (7)

[0048] When the system is operating in the negative half-cycle, the system output is:

[0049] I out =|i d2 |=|i t1 +i t2 | (8)

[0050] By combining equations (6), (7), and (8), we can obtain:

[0051] I out =|2it1 |=|2i t2 | (9)

[0052] Among them, i d1 i d2 This represents the current of rectifier diodes D1 and D2; clearly, throughout the entire cycle, the system output current is twice that of a single receiving coil.

[0053] When the system operates in mode B, since the operating principle is the same in both the positive and negative half-cycles, and there are two operating states in each half-cycle, to simplify the analysis, we will analyze the operating state of the positive half-cycle of mode B; because the mutual inductance between the receiving coils #1,2 and the segmented transmitting coils #1,2 is not equal, let i t2 >i t1 For example (i t1 >i t2 Similarly, analyze the system output characteristics under state ①:

[0054]

[0055] Among them, V out Indicates the system output voltage, u t1 and u t2 The AC output voltage at the receiving end, u n1 and u n2 i n1 and i n2 M represents the voltage and current on the primary and secondary sides of the anti-coupling transformer. t L is the primary winding of the anti-coupling transformer in the current multiplier rectifier. n1 With secondary side L n2 Mutual inductance, and the original edge L n1 With secondary side L n2 The magnitudes are equal, and the coupling coefficient is k, which can be expressed as:

[0056]

[0057] When the coupling coefficient k approaches 1, by combining equations (10) and (11), the system output voltage relationship can be obtained:

[0058] 2V out =|u t2 | (12)

[0059] Further analysis reveals the system output characteristics when operating in mode B, state ②:

[0060]

[0061] Similarly, the system output voltage relationship can be solved:

[0062] 2Vout =|u t1 | (14)

[0063] It can be seen that regardless of whether the system is operating in state ① or state ②, its output voltage is always half of the AC output voltage of a single receiving coil, that is, the output current is always twice the AC output current of a single receiving coil.

[0064] Therefore, when the dual receiving coils move along the segmented transmitting coil, the side-by-side placement of the two receiving coils ensures that when one receiving coil passes through the segment of the transmitting coil, the other receiving coil is in a position with relatively stable mutual inductance. Thus, even if the mutual inductance of receiving coil #1 drops significantly at the segment, the current output by receiving coil #2, which is in a relatively stable position, through the current doubler rectifier can always maintain a current gain of 2. This solves the problem of output power fluctuation when passing through segments in traditional dynamic wireless power supply systems, achieving stable system output.

[0065] The correctness of the above conclusions was further verified through testing, and the test results are as follows: Figures 3-5 As shown, where:

[0066] Figure 3 The diagram shows the mutual inductance fluctuations of the segmented transmitting coil and dual receiving coils as their positions change; M 11 +M 12 This indicates the change in mutual inductance of receiving coil #1; M 21 +M 22 This indicates the change in mutual inductance of receiving coil #2. (From...) Figure 3 It is known that when the coil moves, the discontinuity of coupling at the segment will cause the mutual inductance to drop. However, due to the use of a dual-receiving coil structure, when one receiving coil is located at the segment, the other receiving coil will necessarily be located in the stable operating range of mutual inductance. Therefore, when the mutual inductance between one receiving coil and the transmitting coil drops, the mutual inductance between the other receiving coil and the transmitting coil will always be at a stable point, ultimately resulting in stable output power.

[0067] Figure 4 The figure shows the simplified topology and operating waveforms of the system when it is operating in mode A. Taking the positive half-cycle as an example, when the sum of the mutual inductances between the receiving coils #1 and #2 and the segmented transmitting coils is the same, the system is operating in mode A. At this time, the output current i of the receiving coil #1 is... t1 With the output current i of receiving coil #2 t2 Same; i t1 Through diodes D1 and D4, load R L and anti-coupling transformer winding L n2 Forming a loop, i t2 Through the anti-coupling transformer winding L n1Diode D1, load R L When diode D4 forms a circuit, the current i in the diode is... d1 For i t1 i t2 Twice that, the output current I out This is the current multiplier output; the working principle is the same in the negative half-cycle.

[0068] Figure 5 The figure shows the simplified topology and operating waveforms of the system when it is operating in mode B. Taking the positive half-cycle as an example, when the sum of the mutual inductances between the receiving coils #1 and #2 and the segmented transmitting coils is different, the system is operating in mode B. At this time, the output current i of the receiving coil #1 is... t1 With the output current i of receiving coil #2 t2 Different. (Based on i) t2 >i t1 For example, in state ①, i t1 After passing through diodes D1 and D4, the load R L and anti-coupling transformer winding L n2 Forming a loop; i t2 Through the anti-coupling transformer winding L n1 Diode D1, load R L It forms a circuit with diode D4; due to the primary winding L of the anti-coupling transformer n1 With secondary winding L n2 The coupling coefficient is approximately 1; therefore, the primary and secondary currents of the anti-coupled transformer are approximately the same, i.e., i t2 =i n1 =i n2 Additionally, the secondary winding output current i n2 Not only does it flow to receiving coil #1, forming i t1 The excess portion of the circuit supplies power to the load through diode D2; therefore, the sum of the currents in diodes D1 and D2 is i. t2 +i n1 Output current I out Approximate current multiplier output; in state ②, due to the output current i of receiving coil #2 t2 The decrease causes the output current i of receiving coils #1 and #2 to decrease. t1 with i t2 The similarity leads to the secondary winding output current i n2 Only the current of receiving coil #1 can be supplied, therefore diode D2 is turned off; due to the primary winding current i of the autotransformer n1 There cannot be a sudden change. At this time, diode D3 conducts and freewheels, and the output current is the current of diode D1, i.e., i d1 =i t1 +i t2 Therefore, the output current I outIt is also approximately a doubled output.

[0069] In summary, when the dual receiving coils move along the segmented transmitting coils, the side-by-side placement of the two receiving coils ensures that when one receiving coil passes through the segment of the transmitting coil, the other receiving coil is in a position of relatively stable mutual inductance. Therefore, even if the mutual inductance of receiving coil #1 drops significantly at the segment, the current output by receiving coil #2, which is in a relatively stable position, through the current doubler rectifier can always maintain a current gain of 2. This solves the problem of output power fluctuation when passing through segments in traditional dynamic wireless power supply systems, achieving stable system output.

[0070] Finally, it should be noted that the above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that all or part of the processes for implementing the above embodiments, and equivalent variations made in accordance with the claims of the present invention, still fall within the scope of the invention.

Claims

1. A dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier, comprising a transmitter and a receiver, characterized in that: The transmitter has segmented transmitting coils arranged along the moving path of the receiver. Each transmitting coil is connected to an AC bus via a corresponding primary-side resonant compensation circuit and a corresponding energy switching switch. The front end of the AC bus is connected to a DC power supply via a high-frequency inverter. The receiver has two receiving coils arranged side by side along the moving direction. Each receiving coil is connected to a corresponding current doubler rectifier input group via a corresponding secondary-side resonant compensation circuit. A filter capacitor and an electrical load are connected to the output group of the current doubler rectifier. The transmitter changes the opening and closing state of the corresponding energy switching switch one by one according to the position of the receiver, in a manner that only two adjacent transmitting coils are energized at the same time. The current multiplier rectifier includes diodes D1, D2, D3, D4, and an anti-coupling transformer T. Diodes D1, D2, D3, and D4 form a full-bridge rectifier circuit. The two coil windings of the anti-coupling transformer T are connected in series on the two common arms of the full-bridge rectifier circuit. The upper ends of the first and second coil windings of the anti-coupling transformer T serve as the first input terminal group and are connected to the secondary resonant compensation circuit corresponding to the first receiving coil. The lower ends of the first and second coil windings of the anti-coupling transformer T serve as the second input terminal group and are connected to the secondary resonant compensation circuit corresponding to the second receiving coil. The upper ends of the first coil winding and the lower ends of the second coil winding are terminals with the same name. Each transmitting coil segment has the same shape and size, and the two receiving coils have the same shape and size, and satisfy the following conditions for at least a certain period of time: ,in: This represents the mutual inductance between the first receiving coil and the first energized transmitting coil; This represents the mutual inductance between the first receiving coil and the second energized transmitting coil; This represents the mutual inductance between the second receiving coil and the first energized transmitting coil; This represents the mutual inductance between the second receiving coil and the second energized transmitting coil.

2. The dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier according to claim 1, characterized in that: Both the primary-side resonant compensation circuit and the secondary-side resonant compensation circuit are LCC compensation circuits.

3. The dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier according to claim 1, characterized in that: Both the transmitting coil and the receiving coil are rectangular planar coils, and the transmitting coil and the receiving coil have the same dimensions in the width direction.

4. The dynamic wireless power supply system based on dual receiving coils and a current multiplier rectifier according to claim 3, characterized in that: A coil gap is reserved between two adjacent transmitting coil sections.

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