A reciprocating distance-adjustable wireless power transmission system

Abstract

The present invention discloses a reciprocating distance-adjustable wireless power transmission system, comprising an excitation source, a wireless power transmission unit, a first magnet, a second magnet, a post-stage conversion unit and a controller, wherein the first magnet and the second magnet are permanent magnets or active magnets, and the first magnet and the second magnet are not permanent magnets at the same time; the front end of the excitation source is connected to a power supply, the rear end of the excitation source is connected to a transmitting coil of the wireless power transmission unit, and the receiving coil of the wireless power transmission unit is connected to the post-stage conversion unit. By flexibly adjusting the size and polarity of the active magnet, the magnetic force generated by the magnets at both ends of the transmitting end and the receiving end is changed to complete the distance change.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless power transmission, and in particular relates to a reciprocating distance-adjustable wireless power transmission system. Background Art

[0002] The transmission distance of wireless power transmission directly affects the system efficiency of wireless power transmission. If the resonant frequency remains unchanged after the transmission distance changes, the efficiency will often decrease. However, in practical applications, especially industrial and commercial applications, it is difficult to require the distance to be just right.

[0003] In the prior art, wireless power transmission systems using fixed spacing or other passive spacings have a reduced transmission efficiency of wireless power because the transmission distance is immutable or cannot be actively changed. Summary of the invention

[0004] The present invention provides a reciprocating distance-adjustable wireless power transmission system, which is used to solve the technical problem that the transmission distance cannot be actively adjusted.

[0005] The present invention provides a reciprocating distance-adjustable wireless power transmission system, comprising an excitation source, a wireless power transmission unit, a first magnet, a second magnet, a post-stage conversion unit, and a controller, wherein the first magnet and the second magnet are permanent magnets or active magnets, and the first magnet and the second magnet are not both permanent magnets;

[0006] The front end of the excitation source is connected to a power source, the rear end of the excitation source is connected to a transmitting coil of the wireless power transmission unit, and the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit;

[0007] Wherein, with the wireless power transmission unit as the boundary, the first magnet is located at the transmitting side, and the second magnet is located at the receiving side. When the first magnet is an active magnet, the first magnet includes a DC-DC conversion unit and an electromagnet connected in series in sequence, and the first magnet is connected to the power supply and then connected in parallel with the excitation source; when the second magnet is an active magnet, the second magnet includes an active rectification unit and an electromagnet connected in series in sequence, and the second magnet is connected to the receiving coil and then connected in parallel with the subsequent conversion unit;

[0008] The controller is used to control the active magnet and the subsequent conversion unit.

[0009] In some embodiments of the present invention, when the first magnet is a permanent magnet and the second magnet is an active magnet, the first magnet is located at the transmitting side as an independent unit, the front end of the excitation source is connected to a power source, and the rear end of the excitation source is connected to the transmitting coil of the wireless power transmission unit;

[0010] When the receiving coil includes a receiving coil A and a receiving coil B, the receiving coil A is specifically supplied to the second magnet, and the second magnet includes an active rectification unit and an electromagnet connected in series in sequence, and the receiving coil B is connected to the subsequent conversion unit, and the active rectification unit controls the magnitude of the active magnet magnetic field by controlling the output current, and controls the polarity of the second magnet by controlling the output polarity of the active rectification unit;

[0011] When there is only one receiving coil, the receiving coil is connected in parallel to the second magnet and the subsequent conversion unit, the second magnet includes an active rectification unit and an electromagnet connected in series in sequence, the active rectification unit controls the magnitude of the active magnet magnetic field by controlling the output current, and controls the polarity of the second magnet by controlling the output polarity of the active rectification unit;

[0012] In some embodiments of the present invention, the second magnet further includes a single-pole double-throw switch K1 and a single-pole double-throw switch K2;

[0013] The polarity of the output of the active rectification unit is fixed, positive at the top and negative at the bottom, the common end of the single-pole double-throw switch K1 is connected to the positive pole of the active rectification unit, the common end of the single-pole double-throw switch K2 is connected to the negative pole of the active rectification unit, the end 11 of the single-pole double-throw switch K1 and the end 11 of the single-pole double-throw switch K2 are both connected to one end of the electromagnet, and the end 22 of the single-pole double-throw switch K1 and the end 22 of the single-pole double-throw switch K2 are both connected to the other end of the electromagnet.

[0014] In some embodiments of the present invention, when the first magnet is an active magnet and the second magnet is a permanent magnet, the first magnet includes a DC-DC conversion unit and an electromagnet connected in series in sequence;

[0015] The DC-DC conversion unit is connected in parallel with the excitation source and both are connected to the power supply. The excitation source is connected to the transmitting coil of the wireless power transmission unit, and the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit. The controller samples the transmission distance d, controls the DC-DC conversion unit and the subsequent conversion unit, and controls the magnitude and polarity of the magnetic field of the first magnet by controlling the magnitude and polarity of the output current Ia of the DC-DC conversion unit, thereby controlling the magnetic force between the first magnet and the second magnet, and further controlling the transmission distance d according to the change in the magnetic force.

[0016] In some embodiments of the present invention, the first magnet further includes a single-pole double-throw switch K1 and a single-pole double-throw switch K2;

[0017] The polarity of the output of the DC-DC conversion unit is fixed, with positive at the top and negative at the bottom. The common end of the single-pole double-throw switch K1 is connected to the positive pole of the DC-DC conversion unit, and the common end of the single-pole double-throw switch K2 is connected to the negative pole of the DC-DC conversion unit. The 11 end of the single-pole double-throw switch K1 and the 11 end of the single-pole double-throw switch K2 are both connected to one end of the electromagnet, and the 22 end of the single-pole double-throw switch K1 and the 22 end of the single-pole double-throw switch K2 are both connected to the other end of the electromagnet.

[0018] In some embodiments of the present invention, when both the first magnet and the second magnet are active magnets,

[0019] The first magnet comprises a DC-DC conversion unit and an electromagnet connected in series in sequence, the DC-DC conversion unit is connected in parallel with the excitation source, and both are connected to a power supply, the excitation source is connected to a transmitting coil of the wireless power transmission unit, the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit and the second magnet, and the subsequent conversion unit is connected in parallel with the second magnet;

[0020] The second magnet includes an active rectification unit and an electromagnet connected in series in sequence. The controller samples the transmission distance d, controls the DC-DC conversion unit, the active rectification unit and the post-stage conversion unit, changes the magnetic field size and polarity of the first magnet by controlling the size of the output current of the DC-DC conversion unit, changes the magnetic field size and polarity of the second magnet by controlling the size of the output current of the active rectification unit, and then controls the magnetic force between the first magnet and the second magnet, so that the transmission distance d is controlled according to the change of the magnetic force.

[0021] In some embodiments of the present invention, the active rectification unit adopts an H-bridge circuit topology, switches Q1 and Q2 are connected in series to form a bridge arm, the common end of switches Q1 and Q2 is A connected to one end of the receiving coil, switches Q3 and Q4 are connected in series to form a bridge arm, the common end of switches Q3 and Q4 is B connected to the other end of the receiving coil, the common end of switch Q1 and switch Q3 is C connected to one end of the electromagnet, and the common end of switch Q2 and switch Q4 is D connected to the other end of the electromagnet;

[0022] The polarity control of the active rectifying unit is as follows: when the input voltage of the active rectifying unit is When the switch Q1 and switch Q4 are closed and the switch Q2 and switch Q3 are open, the output voltage of the active rectifier unit is positive;

[0023] When the input voltage of the active rectifier unit When the output voltage of the active rectifier unit is negative, the switches Q1 and Q4 are disconnected and the switches Q2 and Q3 are closed. is negative;

[0024] When the input voltage of the active rectifier unit When the switch Q1 and switch Q4 are turned off and the switch Q2 and switch Q3 are turned on, the output voltage of the active rectifier unit is positive;

[0025] When the input voltage of the active rectifier unit When the output voltage of the active rectifier unit is negative, the switches Q1 and Q4 are closed and the switches Q2 and Q3 are open. is negative;

[0026] In the polarity control of the active rectifying unit, the output voltage of the active rectifying unit is adjusted by controlling the duty cycle. size.

[0027] The reciprocating distance-adjustable wireless power transmission system of the present application flexibly adjusts the size and polarity of the active magnet to change the magnetic force generated by the magnets at both ends of the transmitting end and the receiving end to achieve variable distance. Compared with the wireless power transmission methods with fixed spacing or other passive spacing in the prior art, it can effectively improve the transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 The structural block diagram of a reciprocating distance-adjustable wireless power transmission system;

[0030] Figure 2 The system structure block diagram is when the permanent magnet is on the transmitting side and the active magnet is on the receiving side;

[0031] Figure 3 The block diagram of the system structure is when the permanent magnet is on the transmitting side and the active magnet is on the receiving side and the switch changes the polarity of the magnet;

[0032] Figure 4 This is a system structure block diagram when the active magnet is on the transmitting side and the permanent magnet is on the receiving side;

[0033] Figure 5 The block diagram of the system structure when the active magnet is on the transmitting side and the permanent magnet is on the receiving side and the switch changes the polarity of the magnet;

[0034] Figure 6 is a system structure block diagram when both the first magnet and the second magnet are active magnets;

[0035] Figure 7 This is the main circuit diagram of the active rectifier unit;

[0036] Figure 8 This is a schematic diagram of the polarity control of the active rectifier unit;

[0037] Fig. 9 The main circuit diagram of the active rectification unit and electromagnet built for MOSFET. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0039] Figure 1 The structural block diagram of a reciprocating distance-adjustable wireless power transmission system.

[0040] The reciprocating distance-adjustable wireless power transmission system of the present application includes an excitation source, a wireless power transmission unit, a first magnet, a second magnet, a subsequent conversion unit, and a controller. The front end of the excitation source is connected to a power supply, the rear end of the excitation source is connected to a transmitting coil of the wireless power transmission unit, and the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit. The first magnet and the second magnet are both of two types: permanent magnets or active magnets. When the first magnet or the second magnet is a permanent magnet, there is no need to install a controllable power supply as an independent body. When the first magnet is an active magnet, the first magnet is connected to the power supply and then connected in parallel with the excitation source. When the second magnet is an active magnet, the second magnet is connected to the receiving coil and then connected in parallel with the subsequent conversion unit. The first magnet and the second magnet cannot be permanent magnets at the same time. The controller controls the active magnet and the subsequent conversion unit.

[0041] The wireless power transmission unit includes a transmitting coil and a receiving coil. The wireless power transmission unit allows a relay solution, that is, it has a relay coil. The wireless power transmission unit is divided into a transmitting side and a receiving side, with the first magnet located on the transmitting side and the second magnet located on the receiving side.

[0042] According to the classification of magnet types, there are three types of reciprocating distance-adjustable wireless power transmission systems, including Type 1: the first magnet is a permanent magnet and the second magnet is an active magnet; Type 2: the first magnet is an active magnet and the second magnet is a permanent magnet; Type 3: both the first magnet and the second magnet are active magnets.

[0043] The reciprocating distance-adjustable wireless power transmission system of the present application changes the generated magnetic force and achieves distance change by flexibly adjusting the magnetic field size and polarity of the active magnet.

[0044] Embodiment 1: The first magnet is a permanent magnet, and the second magnet is an active magnet; Figure 2 , Figure 3 All of them are applications of Example 1.

[0045] Figure 2 This is the system block diagram when the permanent magnet is on the transmitting side and the active magnet is on the receiving side.

[0046] Embodiment 1: When the first magnet is a permanent magnet, the second magnet is an active magnet, the permanent magnet is on the transmitting side and the active magnet is on the receiving side, the system:

[0047] The first magnet is a permanent magnet, which is located on the transmitting side as an independent unit. The front end of the excitation source is connected to the power supply, and the rear end of the excitation source is connected to the transmitting coil of the wireless power transmission unit. According to the different receiving coils, there are two types of schemes on the receiving side, corresponding to Figure 2 Middle (a), Figure 2 (b) in the middle. The controller controls the active rectifier unit and the subsequent conversion unit. The control target of the active rectifier unit is to meet the transmission distance requirements of the system, so that variable distance control can be achieved. By controlling the output current Ia of the active rectifier unit, the magnetic field size and polarity of the electromagnet are controlled, and then the size and direction of the magnetic force F are changed to resist or strengthen gravity G or other types of applied forces Fa, such as elastic force Fs; finally, reciprocating distance adjustable variable distance control is achieved.

[0048] Regardless of whether the first magnet and the second magnet are permanent magnets or active magnets, in order to increase the magnetic force F, the distance between the permanent magnet and the electromagnet needs to be as short as possible. Therefore, the permanent magnet and the electromagnet are as close to the edge of the transmitting side or the receiving side as possible during physical layout.

[0049] Example 1 has three schemes, namely, Example 1-(a), 1-(b), and 1-(c).

[0050] Figure 2 (a) is a block diagram of the active magnet solution system provided by a dedicated receiving coil.

[0051] The receiving coil of embodiment 1-(a) includes a receiving coil A and a receiving coil B. The receiving coil A is specifically supplied to the second magnet. In this case, the second magnet is an active magnet. The second magnet includes an active rectifier unit and an electromagnet connected in series in sequence. The receiving coil B of the wireless power transmission unit is connected to the subsequent conversion unit. The active rectifier unit controls the magnetic field size of the active magnet by controlling the output current, and controls the polarity of the active magnet by controlling the output polarity of the active rectifier unit.

[0052] The advantage of this solution is that the active magnet is relatively independent from the subsequent conversion and load, thus avoiding mutual influence.

[0053] Figure 2 (b) is the system block diagram of the shared receiving coil solution.

[0054] Embodiment 1-(b) has only one receiving coil, and the receiving coil is connected in parallel with a second magnet and a subsequent conversion unit. The second magnet is an active magnet, and the second magnet includes an active rectifier unit and an electromagnet connected in series. The active rectifier unit controls the magnitude of the active magnet's magnetic field by controlling the output current, and controls the polarity of the active magnet by controlling the output polarity of the active rectifier unit. The advantage of this solution is that the cost is lower.

[0055] Figure 3 The block diagram of the system structure is when the permanent magnet is on the transmitting side and the active magnet is on the receiving side and the switch changes the polarity of the magnet;

[0056] Embodiment 1-(c): The difference of the system in which the permanent magnet is on the transmitting side and the active magnet is on the receiving side and the switch changes the polarity of the magnet is that the second magnet includes three parts connected in series: an active rectifier unit, a single-pole double-throw switch K1 and a single-pole double-throw switch K2, and an electromagnet; the polarity of the output of the active rectifier unit is fixed, positive at the top and negative at the bottom, the common end of the single-pole double-throw switch K1 is connected to the positive pole of the active rectifier unit, the common end of the single-pole double-throw switch K2 is connected to the negative pole of the active rectifier unit, the 11 end of the single-pole double-throw switch K1 and the 11 end of the single-pole double-throw switch K2 are both connected to one end of the electromagnet, the 22 end of the single-pole double-throw switch K1 and the 22 end of the single-pole double-throw switch K2 are both connected to the other end of the electromagnet; the rest is the same as the special receiving coil supplying the active magnet scheme. The single-pole double-throw switch selection relay or power electronic switch is composed and controlled by a controller; the active rectifier unit is only used to control the current size but not the current polarity.

[0057] Among the three sub-schemes of Example 1, Examples 1-(a) and 1-(b) are preferred.

[0058] Figure 3 (a) is a block diagram of a system that uses a switch to change the polarity of the magnet when a dedicated receiving coil supplies an active magnet.

[0059] Figure 3 (b) is a system block diagram of a shared receiving coil solution using a switch to change the polarity of the magnet.

[0060] Embodiment 1 preferably uses an active rectifier unit to control the magnitude and polarity of the magnetic field of the electromagnet, that is, Figure 2 plan.

[0061] Embodiment 2: The first magnet is an active magnet, and the second magnet is a permanent magnet; Figure 4 , Figure 5 All of them are applications of Example 2.

[0062] Figure 4 This is a system structure block diagram when the active magnet is on the transmitting side and the permanent magnet is on the receiving side;

[0063] Embodiment 2: A system in which the first magnet is an active magnet, the second magnet is a permanent magnet, the active magnet is on the transmitting side and the permanent magnet is on the receiving side, and a switch changes the polarity of the magnets comprises a first magnet, an excitation source, a wireless power transmission unit, a subsequent conversion unit, and a second magnet;

[0064] Among them, Example 2 has two schemes, Example 2-(a) and 2-(b).

[0065] Embodiment 2-(a): The first magnet is an active magnet, and the first magnet includes a DC-DC conversion unit and an electromagnet connected in series in sequence; the DC-DC conversion unit is connected in parallel with the excitation source, and both are connected after the power supply, the excitation source is connected to the transmitting coil of the wireless power transmission unit, and the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit. The controller samples the transmission distance d, controls the DC-DC conversion unit and the subsequent conversion unit, and controls the magnetic field size and polarity of the first magnet by controlling the size and polarity of the output current Ia of the DC-DC conversion unit, thereby controlling the magnetic force between the first magnet and the second magnet, and further controlling the transmission distance d according to the change of the magnetic force.

[0066] Figure 5 The block diagram of the system is when the active magnet is on the transmitting side and the permanent magnet is on the receiving side and the switch changes the polarity of the magnet;

[0067] Embodiment 2-(b): The first magnet is an active magnet, the second magnet is a permanent magnet, the active magnet is on the transmitting side and the permanent magnet is on the receiving side, the system comprises the first magnet, an excitation source, a wireless power transmission unit, a post-stage conversion unit, and the second magnet; the first magnet is an active magnet, the first magnet comprises a DC-DC conversion unit, a single-pole double-throw switch K1 and a single-pole double-throw switch K2 and an electromagnet connected in series in sequence; the single-pole double-throw switch selection relay or power electronic switch is controlled by a controller; the DC-DC conversion unit is connected in parallel with the excitation source, and both are connected In the power supply, the excitation source is connected to the transmitting coil of the wireless power transmission unit, the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit, the controller samples the transmission distance d, controls the DC-DC conversion unit and the subsequent conversion unit, controls the magnetic field size of the first magnet by controlling the size of the output current Ia of the DC-DC conversion unit, controls the magnetic field polarity of the first magnet by controlling the single-pole double-throw switch K1 and the single-pole double-throw switch K2, and then controls the magnetic force between the first magnet and the second magnet, and further controls the transmission distance d according to the change of the magnetic force.

[0068] The polarity of the output of the DC-DC conversion unit is fixed, positive at the top and negative at the bottom. The common end of the single-pole double-throw switch K1 is connected to the positive pole of the active rectification unit, the common end of the single-pole double-throw switch K2 is connected to the negative pole of the active rectification unit, the end 11 of the single-pole double-throw switch K1 and the end 11 of the single-pole double-throw switch K2 are both connected to one end of the electromagnet, and the end 22 of the single-pole double-throw switch K1 and the end 22 of the single-pole double-throw switch K2 are both connected to the other end of the electromagnet.

[0069] Embodiment 3: Both the first magnet and the second magnet are active magnets.

[0070] Figure 6 This is a system structure block diagram when the first magnet and the second magnet are both active magnets.

[0071] When both the first magnet and the second magnet are active magnets, the system includes the first magnet, an excitation source, a wireless power transmission unit, a subsequent conversion unit, and the second magnet; the first magnet is an active magnet, the first magnet includes a DC-DC conversion unit and an electromagnet connected in series in sequence, the DC-DC conversion unit is connected in parallel with the excitation source, and both are connected after the power supply, the excitation source is connected to the transmitting coil of the wireless power transmission unit, the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit and the second magnet, the subsequent conversion unit is connected in parallel with the second magnet, the second magnet is an active magnet, and the second magnet includes an active rectification unit and an electromagnet connected in series in sequence; the controller samples the transmission distance d, controls the DC-DC conversion unit, the active rectification unit, and the subsequent conversion unit, controls the magnetic field size and magnetic field polarity of the first magnet by controlling the size of the output current of the DC-DC conversion unit, controls the magnetic field size and polarity of the second magnet by controlling the output current of the active rectification unit, thereby controlling the magnetic force between the first magnet and the second magnet, and further controlling the transmission distance d according to the change of the magnetic force.

[0072] Supplementary explanation: In Example 3: the first magnet and the second magnet are both active magnets. Although the first magnet and the second magnet can both change polarity, and both can be changed by adding switches such as single-pole double-throw switch K1 and single-pole double-throw switch K2, in application, only one of the first magnet and the second magnet needs to be able to change polarity. It is preferred that the active rectification unit implements polarity control and does not insert a switch.

[0073] In the application, one of the three embodiments can be selected, and embodiment 1 and embodiment 2 are preferred.

[0074] Figure 7 This is the main circuit diagram of the active rectifier unit;

[0075] The active rectification unit adopts an H-bridge circuit topology. Switch Q1 and switch Q2 are connected in series to form a bridge arm. The common end of switch Q1 and switch Q2 is A, which is connected to one end of the receiving coil. Switch Q3 and switch Q4 are connected in series to form a bridge arm. The common end of switch Q3 and switch Q4 is B, which is connected to the other end of the receiving coil. The common end of switch Q1 and switch Q3 is C, which is connected to one end of the electromagnet. The common end of switch Q2 and switch Q4 is D, which is connected to the other end of the electromagnet.

[0076] Figure 8 This is a schematic diagram of the polarity control of the active rectifier unit;

[0077] The polarity control of the active rectifier unit is: when the input voltage of the active rectifier unit When the switch Q1 and switch Q4 are closed and the switch Q2 and switch Q3 are open, the output voltage of the active rectifier unit is positive, such as Figure 8 As shown in (a); when the input voltage of the active rectifier unit When the output voltage of the active rectifier unit is negative, the switches Q1 and Q4 are disconnected and the switches Q2 and Q3 are closed. is negative, such as Figure 8 As shown in (b); when the input voltage of the active rectifier unit When the switch Q1 and switch Q4 are turned off and the switch Q2 and switch Q3 are turned on, the output voltage of the active rectifier unit is positive, such as Figure 8 As shown in (c); when the input voltage of the active rectifier unit When the output voltage of the active rectifier unit is negative, the switches Q1 and Q4 are closed and the switches Q2 and Q3 are open. is negative, such as Figure 8 As shown in (d) in the figure; the above working conditions all control the output voltage of the active rectifier unit by controlling the duty cycle. size.

[0078] Supplementary explanation: The DC-DC conversion unit can adopt an H-bridge circuit topology, that is, can adopt the same circuit topology and polarity control scheme as the active rectification unit. The DC-DC conversion unit can also adopt other suitable DC-DC topologies.

[0079] Fig. 9 The main circuit diagram of the active rectification unit and electromagnet built for MOSFET.

[0080] For the convenience of description, the present invention provides a practical active rectification unit + electromagnet main circuit diagram, the circuit is composed of an H bridge composed of switch Q1, switch Q2, switch Q3, and switch Q4, and switch Q1, switch Q2, switch Q3, and switch Q4 are all metal oxide semiconductor field effect tubes MOSFET, and the electromagnet is used as a filter inductor. In actual applications, other suitable power electronic devices can be flexibly selected according to needs.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A reciprocating distance-adjustable wireless power transmission system, characterized in that: The invention comprises an excitation source, a wireless power transmission unit, a first magnet, a second magnet, a post-stage conversion unit and a controller, wherein the first magnet and the second magnet are permanent magnets or active magnets, and the first magnet and the second magnet are not permanent magnets at the same time; The front end of the excitation source is connected to a power source, the rear end of the excitation source is connected to a transmitting coil of the wireless power transmission unit, and the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit; Wherein, with the wireless power transmission unit as the boundary, the first magnet is located at the transmitting side, and the second magnet is located at the receiving side. When the type of the first magnet is an active magnet, the first magnet includes a DC-DC conversion unit and an electromagnet connected in series in sequence, and the first magnet is connected to the power supply and then connected in parallel with the excitation source; when the type of the second magnet is an active magnet, the second magnet includes an active rectification unit and an electromagnet connected in series in sequence, and the second magnet is connected to the receiving coil and then connected in parallel with the subsequent conversion unit, wherein the active rectification unit adopts an H-bridge circuit topology, switches Q1 and Q2 are connected in series to form a bridge arm, the common end of switches Q1 and Q2 is A connected to one end of the receiving coil, switches Q3 and Q4 are connected in series to form a bridge arm, the common end of switches Q3 and Q4 is B connected to the other end of the receiving coil, the common end of switch Q1 and switch Q3 is C connected to one end of the electromagnet, and the common end of switch Q2 and switch Q4 is D connected to the other end of the electromagnet; The polarity control of the active rectifying unit is as follows: when the input voltage of the active rectifying unit is positive, the switches Q1 and Q4 are closed and the switches Q2 and Q3 are opened, then the output voltage of the active rectifying unit is positive; When the input voltage of the active rectifying unit is negative, the switches Q1 and Q4 are disconnected and the switches Q2 and Q3 are closed, and the output voltage of the active rectifying unit is negative; When the input voltage of the active rectifying unit is positive, the switches Q1 and Q4 are disconnected and the switches Q2 and Q3 are closed, and the output voltage of the active rectifying unit is positive; When the input voltage of the active rectifying unit is negative, the switch Q1 and the switch Q4 are closed and the switch Q2 and the switch Q3 are opened, and the output voltage of the active rectifying unit is negative; In the polarity control of the active rectifying unit, the magnitude of the output voltage of the active rectifying unit is adjusted by controlling the duty cycle; The controller is used to control the active magnet and the subsequent conversion unit.

2. A reciprocating distance-adjustable wireless power transmission system according to claim 1, characterized in that: When the first magnet is a permanent magnet and the second magnet is an active magnet, the first magnet is located at the transmitting side as an independent unit, the front end of the excitation source is connected to a power source, and the rear end of the excitation source is connected to a transmitting coil of the wireless power transmission unit; When the receiving coil includes a receiving coil A and a receiving coil B, the receiving coil A is specifically supplied to the second magnet, and the second magnet includes an active rectification unit and an electromagnet connected in series in sequence, and the receiving coil B is connected to the subsequent conversion unit, and the active rectification unit controls the magnitude of the active magnet magnetic field by controlling the output current, and controls the polarity of the second magnet by controlling the output polarity of the active rectification unit; When there is only one receiving coil, the receiving coil is connected in parallel to the second magnet and the subsequent conversion unit. The second magnet includes an active rectification unit and an electromagnet connected in series in sequence. The active rectification unit controls the magnetic field size of the active magnet by controlling the output current, and controls the polarity of the second magnet by controlling the output polarity of the active rectification unit.

3. A reciprocating distance-adjustable wireless power transmission system according to claim 2, characterized in that: in, The second magnet also includes a single-pole double-throw switch K1 and a single-pole double-throw switch K2; The polarity of the output of the active rectification unit is fixed, positive at the top and negative at the bottom, the common end of the single-pole double-throw switch K1 is connected to the positive pole of the active rectification unit, the common end of the single-pole double-throw switch K2 is connected to the negative pole of the active rectification unit, the end 11 of the single-pole double-throw switch K1 and the end 11 of the single-pole double-throw switch K2 are both connected to one end of the electromagnet, and the end 22 of the single-pole double-throw switch K1 and the end 22 of the single-pole double-throw switch K2 are both connected to the other end of the electromagnet.

4. The reciprocating distance-adjustable wireless power transmission system according to claim 1, characterized in that: When the first magnet is an active magnet and the second magnet is a permanent magnet, the first magnet includes a DC-DC conversion unit and an electromagnet connected in series in sequence; The DC-DC conversion unit is connected in parallel with the excitation source and both are connected to the power supply. The excitation source is connected to the transmitting coil of the wireless power transmission unit, and the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit. The controller samples the transmission distance d, controls the DC-DC conversion unit and the subsequent conversion unit, and controls the magnitude and polarity of the magnetic field of the first magnet by controlling the magnitude and polarity of the output current Ia of the DC-DC conversion unit, thereby controlling the magnetic force between the first magnet and the second magnet, and further controlling the transmission distance d according to the change in the magnetic force.

5. A reciprocating distance-adjustable wireless power transmission system according to claim 4, characterized in that: in, The first magnet also includes a single-pole double-throw switch K1 and a single-pole double-throw switch K2; The polarity of the output of the DC-DC conversion unit is fixed, with positive at the top and negative at the bottom. The common end of the single-pole double-throw switch K1 is connected to the positive pole of the DC-DC conversion unit, and the common end of the single-pole double-throw switch K2 is connected to the negative pole of the DC-DC conversion unit. The 11 end of the single-pole double-throw switch K1 and the 11 end of the single-pole double-throw switch K2 are both connected to one end of the electromagnet, and the 22 end of the single-pole double-throw switch K1 and the 22 end of the single-pole double-throw switch K2 are both connected to the other end of the electromagnet.

6. The reciprocating distance-adjustable wireless power transmission system according to claim 1, characterized in that: When the first magnet and the second magnet are both active magnets, The first magnet includes a DC-DC conversion unit and an electromagnet connected in series in sequence, the DC-DC conversion unit is connected in parallel with the excitation source, and both are connected to a power supply, the excitation source is connected to a transmitting coil of the wireless power transmission unit, the receiving coil of the wireless power transmission unit is connected to the subsequent conversion unit and the second magnet, and the subsequent conversion unit is connected in parallel with the second magnet; the second magnet includes an active rectification unit and an electromagnet connected in series in sequence, the controller samples the transmission distance d, controls the DC-DC conversion unit, the active rectification unit and the subsequent conversion unit, changes the magnetic field size and polarity of the first magnet by controlling the output current of the DC-DC conversion unit, changes the magnetic field size and polarity of the second magnet by controlling the output current of the active rectification unit, and further controls the magnetic force between the first magnet and the second magnet, so that the transmission distance d is controlled according to the change of the magnetic force.

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