Anti-offset constant-current hybrid compensation topological structure and parameter construction method thereof

Abstract

The invention discloses an anti-offset constant-current hybrid compensation topological structure and a parameter construction method thereof, belongs to the technical field of wireless power transmission, and aims to solve the problems of large output voltage or current fluctuation and low transmission efficiency caused by offset of a primary side coil and a secondary side coil in an IPT system. The structure comprises a direct-current power supply, a single-phase full-bridge inverter circuit, two primary side transmitting circuits, two secondary side receiving circuits, a rectification filter circuit and a load, by introducing an adjustment factor, the output gain of the first compensation topology circuit is adjusted, the output curve is slowed down, and the balance of the output gain of the system is realized; compensation structural element parameters are reasonably designed, so that the sum of output gains of the two compensation topologies is relatively constant in an offset range, and the anti-offset constant-current output characteristic of the system is enhanced; according to the invention, the regulation factor and the hybrid compensation structure are utilized to effectively cope with the output current change caused by coil offset, so that constant current output is realized, the system stability and transmission efficiency are improved, the coil design difficulty is reduced, and the application range is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless power transmission, and in particular to a hybrid compensation topology structure of an anti-offset constant current and a parameter construction method thereof. Background Art

[0002] As an emerging contactless energy transmission method, inductive power transfer (IPT) has shown significant advantages and broad application prospects compared to traditional wired charging. This technology uses the principle of electromagnetic induction to achieve complete electrical isolation between the power supply and the load, fundamentally avoiding the risk of electric shock caused by traditional plug-in charging, and greatly improving the safety of the charging process. In addition, IPT technology also eliminates the fire hazard caused by loose or aging wire interfaces, further reducing safety risks.

[0003] In terms of convenience, inductive wireless power transmission technology also performs well. Users only need to place the device on the charging base to start the charging process without complicated plugging and unplugging operations. This feature enables IPT technology to easily adapt to various charging environments such as home, office, and public places, providing users with more flexible and diverse charging solutions.

[0004] However, as IPT technology gradually becomes practical, a problem that cannot be ignored gradually emerges: the primary and secondary coils of the IPT system will inevitably shift during the charging process. This shift will directly affect the mutual inductance between the coils, which will in turn cause large fluctuations in the output voltage or current, significantly reduce the transmission efficiency, and be detrimental to the overall stability of the system. In order to deal with this problem, the industry currently adopts the following solutions: First, improvements can be made from the perspective of control strategy; by monitoring the changes in output voltage or current in real time, the control parameters of the system can be dynamically adjusted to maintain a stable output. However, this method requires high-precision sensors and fast-response control algorithms, which not only increases the complexity of the system, but may also lead to increased costs.

[0005] Secondly, starting from the design of the coupling coil, the structure and layout of the coil are optimized to improve the system's anti-drift capability. Among them, the use of a hybrid compensation structure is one of the better solutions for achieving IPT system anti-drift. However, most hybrid compensation structures have limitations in parameter design and cannot improve the system's anti-drift capability by effectively regulating the compensation capacitor parameters. Most parameter optimizations are still focused on the parameter optimization of the coil, which to a certain extent limits the flexibility and freedom of system design.

[0006] In the prior art, for example, CN108695957B discloses a parameter optimization method for a wireless power transmission device with constant current output that is resistant to offset, which relates to the field of wireless charging; it includes the following steps 1: constructing a topological structure in which two variables that are superimposed on each other change relatively with the change of mutual inductance; step 2: setting the initial value of the ratio between the mutual inductance and the compensation inductance according to the topological structure; step 3: solving the initial value of the ratio according to the output current change amount and the output current ratio when the coil of the topological structure is offset and the given range of the change amount to complete the optimization; the method uses two compensation topologies that are in direct and inverse proportion to the output gain to achieve constant current charging, the first receiving module can output constant current charging that is independent of the load, and in the engineering of coil offset, the output current will decrease accordingly, the second receiving module can also output constant current output that is independent of the load, and in the engineering of coil offset, the output current will increase accordingly, the two output currents are superimposed to achieve a constant method, the invention can achieve constant current charging with offset resistance, and can have good offset resistance for the offset of the coil within a small range. However, once the coil offset is too large, the output current of the second receiving module will dominate. At this time, the output current is completely dependent on the second receiving module. Then the output current of the first receiving module will have little effect on the system, and the system will no longer have the ability to resist offset.

[0007] In summary, the prior art still has many deficiencies in dealing with the offset problem of the primary and secondary coils of the IPT system, especially in the parameter design of the hybrid compensation structure, which still needs further research and optimization. Therefore, the present invention proposes a hybrid compensation topology structure with anti-offset constant current and a parameter construction method thereof, aiming to adjust the output current change trend of the first compensation topology circuit by introducing an adjustment factor, thereby solving the problem of excessive output current change caused by excessive offset, and improving the system's anti-offset capability and stability. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a hybrid compensation topology structure with anti-offset constant current and a parameter construction method thereof, so as to solve the problem of large output voltage or current fluctuation and reduced transmission efficiency caused by the offset between the primary and secondary coils in the inductive power transmission (IPT) system.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: an anti-offset constant current hybrid compensation topology structure, including a DC power supply, a DC power supply connected in series with a single-phase full-bridge inverter circuit, the full-bridge inverter circuit provides high-frequency AC power to a first primary transmitting circuit and a second primary transmitting circuit, the first primary transmitting circuit includes a first primary compensation inductor, a first primary parallel compensation capacitor, a first primary series compensation capacitor and a first primary transmitting coil connected in series and parallel, the first secondary receiving circuit includes a first secondary receiving coil and a first secondary compensation capacitor connected in series, the first secondary receiving circuit is electromagnetically coupled with the first primary transmitting coil of the first primary transmitting circuit through the first secondary receiving coil, the second primary transmitting circuit includes a second primary compensation inductor, a second primary parallel compensation capacitor, a second primary series compensation capacitor and a second primary transmitting coil connected in series and parallel, and the second secondary receiving circuit includes a second secondary receiving coil, a second secondary series compensation capacitor, a second secondary parallel compensation capacitor and a second secondary compensation inductor connected in series and parallel.

[0010] In a preferred embodiment, the hybrid compensation structure with anti-offset constant current is characterized in that: the first primary transmitting circuit and the first secondary receiving circuit together constitute a first compensation topology circuit, the second primary transmitting circuit and the second secondary receiving circuit together constitute a second compensation topology circuit, an input end of the first compensation topology circuit and an input end of the second compensation topology circuit are connected, and both are connected to an output end of the full-bridge inverter circuit, the other input end of the first compensation topology circuit and the other input end of the second compensation topology circuit are connected, and both are connected to the other output end of the full-bridge inverter circuit, an output end of the first compensation topology circuit and an output end of the second compensation topology circuit are connected, and both are connected to an input end of the rectifier and filter circuit, the other output end of the first compensation topology circuit and the other output end of the second compensation topology circuit are connected, and both are connected to the other input end of the rectifier and filter circuit, and both ends of the output of the rectifier and filter circuit are respectively connected to both ends of the load.

[0011] In a preferred embodiment, the hybrid compensation topology structure with anti-offset constant current is characterized in that: one end of the first primary compensation inductor is connected to one end of the single-phase full-bridge inverter circuit, the other end of the first primary compensation inductor is connected to one end of the first primary parallel compensation capacitor, and both are connected to one end of the first primary series compensation capacitor, one end of the first primary transmitting coil is connected to the other end of the first primary series compensation capacitor, the other end of the first primary parallel compensation capacitor is connected to the other end of the first primary transmitting coil, and both are connected to the other end of the single-phase full-bridge inverter circuit, one end of the second primary compensation inductor is connected to one end of the single-phase full-bridge inverter circuit, the other end of the second primary compensation inductor is connected to one end of the second primary parallel compensation capacitor, and both are connected to one end of the second primary series compensation capacitor, one end of the second primary transmitting coil is connected to the other end of the second primary series compensation capacitor, the other end of the second primary parallel compensation capacitor is connected to the other end of the second primary transmitting coil, and both are connected to the other end of the single-phase full-bridge inverter circuit.

[0012] In a preferred embodiment, the hybrid compensation topology structure with anti-offset constant current is characterized in that: one end of the first secondary receiving coil is connected to one end of the first secondary compensation capacitor, the other end of the first secondary receiving coil is connected to one end of the rectifier and filter circuit, the other end of the first secondary compensation capacitor is connected to the other end of the rectifier and filter circuit, one end of the second secondary receiving coil is connected to one end of the rectifier and filter circuit, the other end of the second secondary receiving coil is connected to one end of the second secondary series compensation capacitor, the other end of the second secondary series compensation capacitor is connected to one end of the second secondary parallel compensation capacitor, and both are connected to one end of the second secondary compensation inductor, the other end of the second secondary parallel compensation capacitor is connected to one end of the rectifier and filter circuit, and the other end of the second secondary compensation inductor is connected to the other end of the rectifier and filter circuit.

[0013] In a preferred solution, the hybrid compensation topology structure with anti-offset constant current is characterized in that the first primary transmitting coil and the first secondary receiving coil are mutual inductance coils with the same end, and the second primary transmitting coil and the second secondary receiving coil are mutual inductance coils with the same end.

[0014] In a preferred embodiment, the hybrid compensation topology structure with anti-offset constant current is characterized in that: the first secondary side receiving circuit output port and the second secondary side receiving circuit output port are connected in parallel to form a combined hybrid compensation topology output port, and the output current of the first secondary side receiving circuit and the output current of the second secondary side receiving circuit jointly provide input current for the rectifier and filter circuit.

[0015] In a preferred embodiment, the hybrid compensation topology structure with anti-offset constant current is characterized in that the first primary transmitting coil, the second primary transmitting coil, the first secondary receiving coil and the second secondary receiving coil are all wound on a magnetic core with Litz wire, and the magnetic core is made of magnetic conductive material.

[0016] A method for constructing parameters of a hybrid compensation topology structure for resisting offset constant current, characterized in that the hybrid compensation topology structure for resisting offset constant current described in any one of the above is adopted, and the method comprises the following steps: Step 1: Determine the system operating frequency according to actual needs 、DC power supply (1) voltage , Input voltage , output current , load (8); Step 2: Determine the first primary transmitting coil , the second primary transmitting coil , the first secondary receiving coil and the second secondary receiving coil The self-inductance, the first primary transmitting coil With the first secondary receiving coil Mutual inductance , the second primary transmitting coil With the second secondary receiving coil Mutual inductance ; Step 3: According to the requirements of system resonance, write Kirchhoff's Voltage Law equation for the first compensation topology circuit and the second compensation topology circuit. The equation is as follows: (1) (2) In the formula is the first primary compensation inductor, is the first primary parallel compensation capacitor, is the first primary series compensation capacitor, is the first secondary compensation capacitor, For the second primary compensation inductor, is the second primary parallel compensation capacitor, is the second primary series compensation capacitor, The second secondary side series compensation capacitor is connected. The second secondary side parallel compensation capacitor is connected. For the second secondary compensation inductor, is the imaginary number symbol, is the input current of the first primary transmitting circuit (3), is the input current of the second primary transmitting circuit (4), is the current flowing through the first primary transmitting coil, is the current flowing through the second primary transmitting coil, is the current flowing through the first secondary receiving coil, is the current flowing through the second secondary receiving coil, is the output current of the second secondary receiving circuit (6), is the angular frequency, is the equivalent load; The current expressions of each branch of the first compensation topology circuit can be solved as follows: (3) definition is the adjustment factor, which is defined as follows: (4) definition is the first influencing parameter, is the second influencing parameter, and its expression is as follows: (5) The second compensation topology circuit satisfies the following conditions: (6) It can be solved that the second compensation topology circuit is obtained in and The expression is as follows: (7); Step 4: From formula (3), we can know that if the output current of the first compensation topology circuit is Regardless of the load, the first compensation topology circuit must satisfy the following equation to satisfy the ZPA input: (8) The currents of the first compensation topology circuit that satisfies the above equation are: (9) Then the output current I o It can be expressed as: (10) When the system is offset, the mutual inductance of the coils of the two compensation topology circuits will decrease accordingly. Obviously, it can be seen from the above formula that the output current gain is inversely proportional to the first compensation topology circuit and proportional to the second compensation topology circuit. If the mutual inductance of the coils changes too much, the output current of the first compensation topology circuit will increase sharply. Therefore, introducing an adjustment factor to adjust the equivalent mutual inductance can prevent the problem of excessive changes in the output current of the first compensation topology circuit. Step 5: Combine the actual system coil parameters and then through reasonable parameter design, the adjustment factor can be determined. Therefore, the values ​​of each compensation capacitor can be obtained as follows: (11).

[0017] The present invention provides a hybrid compensation topology structure with anti-offset constant current and a parameter construction method thereof, which has the following beneficial effects: 1. The present invention utilizes the phenomenon that the mutual inductance is reduced due to the coil offset, and through reasonable parameter design, the output gain of the two compensation topology circuits is proportional and inversely proportional to the change of the coil mutual inductance, respectively, and the output current is superimposed together to realize the system output anti-offset characteristic; 2. Compared with the traditional hybrid compensation topology, the present invention can adjust the function of parameters according to the actual environment, and use the adjustment factor to adjust the output current of the first compensation topology circuit, which effectively prevents the output current of the first compensation topology circuit from fluctuating too much due to excessive offset, thereby causing the system to lose its anti-offset ability; 3. Through reasonable parameter design, the system can achieve constant current output under different load conditions, realize constant current output independent of load, and have the ability of output anti-drift, which further improves the stability and practicality of the system; 4. The present invention introduces an adjustment factor to adjust the output gain of the first compensation topology circuit, slows down the output curve of the first compensation topology circuit, and is used to balance the overall output gain of the system, thereby solving the problem that the output gain of the hybrid supplementary topology depends on the mutual inductance ratio of the coil, and provides a new parameter design scheme for the hybrid topology compensation constant current output; 5. The present invention can reduce the fluctuation of output current by introducing an adjustment factor, and solve the problem of excessive output current variation caused by excessive offset; 6. The present invention transfers the degree of freedom of coil design to the parameter optimization of the compensation topology, which greatly reduces the difficulty of system design. Through reasonable parameter design, the sum of the output gains of the two complementary topologies can be relatively constant within a certain offset range, so that the system has a strong anti-offset constant current output characteristic, ensuring that the system can still output a constant current when the mutual inductance of the coil changes greatly; 7. The technical solution of the present invention does not require high-precision sensors and fast-response control algorithms, thus reducing the complexity and cost of the system; 8. The present invention transfers the freedom of coil design to the parameter optimization of compensation topology, improves the freedom of coil design, and provides greater flexibility for coil design; 9. The present invention has significant innovation and practicality in the field of wireless power transmission technology, and provides a new and effective solution to the offset problem in the IPT system. This solution dynamically adjusts the position and parameters of the transmitting and receiving coils to achieve efficient and stable power transmission when the device position is offset, greatly improving the adaptability of the IPT system and user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 is a schematic diagram of a wireless power transmission system of the present invention; Figure 2 It is a schematic diagram of a hybrid compensation topology circuit of the present invention; Figure 3 Schematic diagram of an equivalent circuit of the hybrid compensation topology circuit of the present invention; Figure 4 A schematic diagram of input voltage and input current of the wireless power transmission system of the present invention; Figure 5 A schematic diagram of output current variation of the wireless charging system of the present invention under different load conditions; Figure 6 A schematic diagram of the output current change of the hybrid compensation topology circuit during the coil deviation process with different modulation factors of the present invention; In the figure: a DC power supply 1, a single-phase full-bridge inverter circuit 2, a first primary transmitting circuit 3, a second primary transmitting circuit 4, a first secondary receiving circuit 5, a second secondary receiving circuit 6, a rectifier and filter circuit 7, and a load 8. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments: Example 1 like Figure 1 As shown, a hybrid compensation structure for anti-offset constant current includes a DC power supply 1, the DC power supply 1 is connected in series with a single-phase full-bridge inverter circuit 2, the full-bridge inverter circuit 2 provides high-frequency AC power to a first primary transmitting circuit 3 and a second primary transmitting circuit 4, the first primary transmitting circuit 3 includes a first primary compensation inductor connected in series and in parallel , the first primary parallel compensation capacitor , the first primary series compensation capacitor and the first primary transmitting coil The first secondary receiving circuit 5 includes a first secondary receiving coil connected in series and the first secondary compensation capacitor The first secondary receiving circuit 5 receives the first secondary receiving coil The first primary transmitting coil of the first primary transmitting circuit 3 Electromagnetic coupling, the second primary transmitting circuit 4 includes a second primary compensation inductor connected in series and parallel , Second primary parallel compensation capacitor , the second primary series compensation capacitor and the second primary transmitting coil The second secondary receiving circuit 6 includes a second secondary receiving coil connected in series and in parallel , the second secondary side series compensation capacitor , the second secondary side parallel compensation capacitor and the second secondary compensation inductor .

[0020] In this embodiment, the hybrid compensation structure with anti-offset constant current is characterized in that: the first primary transmitting circuit 3 and the first secondary receiving circuit 5 together constitute a first compensation topology circuit, the second primary transmitting circuit 4 and the second secondary receiving circuit 6 together constitute a second compensation topology circuit, an input end of the first compensation topology circuit is connected to an input end of the second compensation topology circuit, and both are connected to an output end of the full-bridge inverter circuit 2, the other input end of the first compensation topology circuit is connected to the other input end of the second compensation topology circuit, and both are connected to the other output end of the full-bridge inverter circuit 2, an output end of the first compensation topology circuit is connected to an output end of the second compensation topology circuit, and both are connected to an input end of the rectifier and filter circuit 7, the other output end of the first compensation topology circuit is connected to the other output end of the second compensation topology circuit, and both are connected to the other input end of the rectifier and filter circuit 7, and the two output ends of the rectifier and filter circuit 7 are respectively connected to the two ends of the load 8.

[0021] Furthermore, the hybrid compensation topology structure with anti-offset constant current is characterized in that: the first primary compensation inductor One end is connected to one end of the single-phase full-bridge inverter circuit 2, and the first primary compensation inductor The other end is connected in parallel with the first primary side to compensate for the capacitor One end is connected to the first primary side and the compensation capacitor is connected in series with the first primary side. One end is connected to the first primary transmitting coil One end is connected in series with the first primary side compensation capacitor The other end is connected to the first primary side, and the compensation capacitor is connected in parallel The other end is connected to the first primary transmitting coil The other end is connected to the other end of the single-phase full-bridge inverter circuit 2, and the second primary compensation inductor One end is connected to one end of the single-phase full-bridge inverter circuit 2, and the second primary compensation inductor The other end is connected in parallel with the second primary side to compensate for the capacitor One end is connected to the second primary side and the compensation capacitor is connected in series with the One end is connected to the second primary transmitting coil One end is connected in series with the second primary side compensation capacitor The other end is connected to the second primary side, and the compensation capacitor is connected in parallel The other end is connected to the second primary transmitting coil The other end is connected to the other end of the single-phase full-bridge inverter circuit 2.

[0022] Furthermore, the hybrid compensation topology structure with anti-offset constant current is characterized in that: the first secondary receiving coil One end and the first secondary compensation capacitor One end is connected to the first secondary receiving coil The other end is connected to one end of the rectifier filter circuit 7, and the first secondary compensation capacitor The other end is connected to the other end of the rectifier filter circuit 7, and the second secondary receiving coil One end is connected to one end of the rectifier filter circuit 7, and the second secondary receiving coil The other end is connected in series with the second secondary compensation capacitor One end is connected, and the second secondary side is connected in series with a compensation capacitor The other end is connected in parallel with the second secondary side to compensate for the capacitor and connected to the second secondary compensation inductor One end is connected, and the second secondary side is connected in parallel with the compensation capacitor The other end is connected to one end of the rectifier filter circuit 7, and the second secondary compensation inductor The other end is connected to the other end of the rectifying and filtering circuit 7.

[0023] Furthermore, the hybrid compensation topology structure with anti-offset constant current is characterized in that: the first primary transmitting coil With the first secondary receiving coil The mutual inductance coil at the same end, the second primary transmitting coil With the second secondary receiving coil It is a mutual inductance coil with the same end.

[0024] Furthermore, the hybrid compensation topology structure with an anti-offset constant current is characterized in that: the output port of the first secondary receiving circuit 5 and the output port of the second secondary receiving circuit 6 are connected in parallel to form a combined hybrid compensation topology output port, and the output current of the first secondary receiving circuit 5 The output current of the second secondary receiving circuit 6 Together they provide input current to the rectifier and filter circuit 7.

[0025] Furthermore, the hybrid compensation topology structure with anti-offset constant current is characterized in that: the first primary transmitting coil , the second primary transmitting coil , the first secondary receiving coil and the second secondary receiving coil Both are wound on the magnetic core with Litz wire, and the magnetic core is made of magnetic conductive material.

[0026] Example 2 In another preferred embodiment, based on Embodiment 1, a parameter construction method of a hybrid compensation topology structure with an anti-offset constant current described in any one of Embodiments 1 is adopted, and the method comprises the following steps: Step 1: Determine the system operating frequency according to actual needs 、DC power supply (1) voltage , Input voltage , output current , load 8; Step 2: Determine the first primary transmitting coil , the second primary transmitting coil , the first secondary receiving coil and the second secondary receiving coil The self-inductance, the first primary transmitting coil With the first secondary receiving coil Mutual inductance , the second primary transmitting coil With the second secondary receiving coil Mutual inductance ; Step 3: According to the requirements of system resonance, write Kirchhoff's Voltage Law equations for the first compensation topology circuit and the second compensation topology circuit. The equations are as follows: (1) (2) In the formula, is the imaginary number symbol, is the input current of the first primary transmitting circuit (3), is the input current of the second primary transmitting circuit (4), is the current flowing through the first primary transmitting coil, is the current flowing through the second primary transmitting coil, is the current flowing through the first secondary receiving coil, is the current flowing through the second secondary receiving coil, is the output current of the second secondary receiving circuit (6), is the angular frequency, is an equivalent load, which is the equivalent load of the rectifier circuit and the load; The current expressions of each branch of the first compensation topology circuit can be solved as follows: (3) definition is the adjustment factor, which is defined as follows: (4) definition is the first influencing parameter, is the second influencing parameter, and its expression is as follows: (5) The second compensation topology circuit satisfies the following conditions: (6) It can be solved that the second compensation topology circuit is obtained in and The expression is as follows: (7); Step 4: From formula (3), we can know that if the output current of the first compensation topology circuit is Regardless of the load, the following equation must be satisfied to make the first compensation topology circuit satisfy the input impedance angle (ZPA) of zero: (8) The currents of the first compensation topology circuit that satisfies the above equation are: (9) Then the output current It can be expressed as (10) When the system is offset, the mutual inductance of the coils of the two compensation topology circuits will decrease accordingly. Obviously, it can be seen from the above formula that the output current gain is inversely proportional to the first compensation topology circuit and proportional to the second compensation topology circuit. If the mutual inductance of the coils changes too much, the output current of the first compensation topology circuit will increase sharply. Therefore, introducing an adjustment factor to adjust the equivalent mutual inductance can prevent the problem of excessive changes in the output current of the first compensation topology circuit. Step 5: Combine the actual system coil parameters and then through reasonable parameter design, the adjustment factor can be determined. α Therefore, the value of each compensation capacitor can be obtained as (11).

[0027] Example 3 In another preferred embodiment, based on the above embodiments 1 and 2, refer to the attached Figure 2 and Figure 3 The hybrid compensation topology structure utilizes two compensation topology circuits in parallel and superimposes the output currents of the two compensation topology circuits to improve the system's anti-offset capability, wherein Figure 2 This is a schematic diagram of the hybrid compensation topology circuit of the present invention. Figure 3 The equivalent circuit diagram of the hybrid compensation topology circuit of the present invention is shown in FIG. Introducing the adjustment factor to adjust the output current of the first compensation topology circuit can effectively prevent the problem of the system output anti-offset capability decreasing due to excessive offset.

[0028] Secondly, the present invention adopts cross-shaped spiral coils at both the transmitting end and the receiving end of the system. This type of coil can decouple the cross-inductance between the coils through reasonable design. Therefore, the equivalent mutual inductance involved in the present invention is only the mutual inductance and mutual inductance , Figure 2 This is a schematic diagram of the hybrid compensation topology circuit of the present invention. Figure 3 The equivalent circuit diagram of the hybrid compensation topology circuit of the present invention is shown in FIG. The circuit theory analysis is performed on it, and Kirchhoff's Voltage Law equation is listed to obtain: According to the requirements of system resonance, Kirchhoff's Voltage Law equation is written for the first compensation topology circuit and the second compensation topology circuit, and the equation is as follows: (1) (2) The current expressions of each branch of the first compensation topology circuit can be solved as follows: (3) definition is the adjustment factor, which is defined as follows: (4) definition is the first influencing parameter, is the second influencing parameter, and its expression is as follows: (5) The second compensation topology circuit satisfies the following conditions: (6) It can be solved that the second compensation topology circuit is obtained in and The expression is as follows: (7); Step 4: From formula (3), we can know that if the output current of the first compensation topology circuit is Regardless of the load, the following equation must be satisfied to make the first compensation topology circuit satisfy the input impedance angle (ZPA) of zero: (8) The currents of the first compensation topology circuit that satisfies the above equation are: (9) Then the output current It can be expressed as (10) When the system is offset, the mutual inductance of the coils of the two compensation topology circuits will decrease accordingly. Obviously, it can be seen from the above formula that the output current gain is inversely proportional to the first compensation topology circuit and proportional to the second compensation topology circuit. If the mutual inductance of the coils changes too much, the output current of the first compensation topology circuit will increase sharply. Therefore, introducing an adjustment factor to adjust the equivalent mutual inductance can prevent the problem of excessive changes in the output current of the first compensation topology circuit. Step 5: Combine the actual system coil parameters and then through reasonable parameter design, the adjustment factor can be determined. α Therefore, the value of each compensation capacitor can be obtained as (11).

[0029] Example 4 In another preferred embodiment, based on the above embodiments 1, 2, and 3, in order to verify the feasibility of the present invention, the first primary transmitting coil , the first secondary receiving coil , the second primary transmitting coil With the second secondary receiving coil Experimental verification is carried out, and the specific parameters are shown in Table 1: Table 1 Wireless charging system parameters

[0030] Depend on Figure 4 It can be seen that the input voltage and the output current are almost in phase, so the hybrid compensation topology of the present invention meets the condition of ZPA=0. However, it can be seen from this figure that the output current value is relatively large, so the efficiency may be reduced. In order to avoid this phenomenon, the compensation inductor , It should not be too small. At the same time, the parameter design of the modulation factor must also take into account the problem that the input current may be too large.

[0031] Depend on Figure 5 It can be seen that when the load changes between 5Ω and 20Ω, the output current changes between 3.734A and 3.423A, and the output current fluctuation rate is 8.23%, which is within the range allowed by the system. Therefore, it can be considered that the system output hardly changes with the change of load, and the system achieves constant current output that is independent of the load.

[0032] Figure 6The figure shows the offset conditions of different adjustment factors within the offset range of 160mm (50% of the system device size). Since the traditional hybrid compensation topology cannot regulate the output current, it is equivalent to an adjustment factor of 1. Obviously, compared with the hybrid compensation topology with adjustable output current provided by the present invention, the traditional hybrid compensation topology has a strong anti-offset capability within the offset range of 120mm. Once the offset exceeds 120mm, the output current will fluctuate greatly. The present invention can use the adjustment factor to reduce the output current fluctuation of the first compensation topology circuit, thereby reducing the fluctuation of the system output current. Therefore, compared with the traditional compensation topology, the hybrid compensation structure with an anti-offset constant current designed by the present invention and its parameter construction method can provide a stronger anti-offset constant current output solution for the IPT system.

[0033] To sum up, a hybrid compensation structure with anti-offset constant current and its parameter construction method can achieve constant current output through reasonable parameter design, and the system output current also has strong anti-offset performance. The introduced adjustment factor can transfer the parameter optimization target from coil parameter optimization to compensation capacitor parameter optimization, which greatly relieves the difficulty of parameter optimization. At the same time, the present invention complies with charging specifications and effectively improves the charging efficiency. The introduction of the adjustment factor: Based on the traditional hybrid compensation topology, the adjustment factor is introduced to adjust the output current change trend of the first compensation topology circuit. This innovation reduces the output current fluctuation and effectively solves the problem of excessive output current variation caused by excessive offset. The anti-offset constant current output adopted by the present invention makes the sum of the output gains of the two compensation topologies relatively constant within a certain offset range by reasonably designing the parameters of each component of the compensation structure, thereby realizing the anti-offset constant current output characteristic of the system. It liberates the freedom of coil design to a certain extent, and transfers the parameter optimization of the coil to the parameter optimization of the compensation topology, greatly reducing the difficulty of system design. The innovative application of the hybrid compensation topology of the present invention adopts a hybrid compensation topology structure, combined with the introduction of an adjustment factor, to realize the anti-offset and constant current characteristics of the output current of the IPT system. This innovative application not only improves the stability and reliability of the system, but also expands the hybrid compensation. The application scope of the topology; a new parameter construction method is proposed. By combining actual measurement with theoretical calculation, key parameters such as system operating frequency, DC power supply voltage, input voltage, output current and load are determined. This innovative method makes the design and optimization of the system more accurate and efficient; utilizing the phenomenon that the mutual inductance decreases due to coil offset, the output gains of the two compensation topology circuits are proportional and inversely proportional to the changes in the coil mutual inductance through reasonable parameter design. This flexible response mechanism enables the system to maintain a stable output current when facing coil offset; in order to verify the feasibility of the scheme, detailed experimental verification is carried out, and the design scheme is continuously optimized and improved during the experiment, which improves the reliability and practicability of the scheme and provides strong support for subsequent practical applications.

Claims

1. A hybrid compensation topology structure with anti-offset constant current, characterized in that: The invention comprises a direct current power supply (1), the direct current power supply (1) is connected in series with a single-phase full-bridge inverter circuit (2), the full-bridge inverter circuit (2) provides high-frequency alternating current to a first primary transmitting circuit (3) and a second primary transmitting circuit (4), the first primary transmitting circuit (3) comprises a first primary compensation inductor, a first primary parallel compensation capacitor, a first primary series compensation capacitor and a first primary transmitting coil connected in series and in parallel, the first secondary receiving circuit (5) comprises a first secondary receiving coil and a first secondary compensation capacitor connected in series, the first secondary receiving circuit (5) is electromagnetically coupled to the first primary transmitting coil of the first primary transmitting circuit (3) via the first secondary receiving coil, the second primary transmitting circuit (4) comprises a second primary compensation inductor, a second primary parallel compensation capacitor, a second primary series compensation capacitor and a second primary transmitting coil connected in series and in parallel, and the second secondary receiving circuit (6) comprises a second secondary receiving coil, a second secondary series compensation capacitor, a second secondary parallel compensation capacitor and a second secondary compensation inductor connected in series and in parallel.

2. According to claim 1, a hybrid compensation topology structure with anti-offset constant current, characterized in that: The first primary transmitting circuit (3) and the first secondary receiving circuit (5) together form a first compensation topology circuit, the second primary transmitting circuit (4) and the second secondary receiving circuit (6) together form a second compensation topology circuit, an input end of the first compensation topology circuit and an input end of the second compensation topology circuit are connected, and are both connected to an output end of the full-bridge inverter circuit (2), the other input end of the first compensation topology circuit and the other input end of the second compensation topology circuit are connected, and are both connected to the other output end of the full-bridge inverter circuit (2), an output end of the first compensation topology circuit and an output end of the second compensation topology circuit are connected, and are both connected to an input end of the rectifier and filter circuit (7), the other output end of the first compensation topology circuit and the other output end of the second compensation topology circuit are connected, and are both connected to the other input end of the rectifier and filter circuit (7), and both ends of the output of the rectifier and filter circuit (7) are respectively connected to two ends of the load (8).

3. According to claim 2, a hybrid compensation topology structure with anti-offset constant current, characterized in that: One end of the first primary compensation inductor is connected to one end of the single-phase full-bridge inverter circuit (2), the other end of the first primary compensation inductor is connected to one end of the first primary parallel compensation capacitor, and both are connected to one end of the first primary series compensation capacitor; one end of the first primary transmitting coil is connected to the other end of the first primary series compensation capacitor, the other end of the first primary parallel compensation capacitor is connected to the other end of the first primary transmitting coil, and both are connected to the other end of the single-phase full-bridge inverter circuit (2); one end of the second primary compensation inductor is connected to one end of the single-phase full-bridge inverter circuit (2), the other end of the second primary compensation inductor is connected to one end of the second primary parallel compensation capacitor, and both are connected to one end of the second primary series compensation capacitor; one end of the second primary transmitting coil is connected to the other end of the second primary series compensation capacitor, the other end of the second primary parallel compensation capacitor is connected to the other end of the second primary transmitting coil, and both are connected to the other end of the single-phase full-bridge inverter circuit (2).

4. The hybrid compensation topology structure with anti-offset constant current according to claim 1, characterized in that: One end of the first secondary receiving coil is connected to one end of the first secondary compensation capacitor, the other end of the first secondary receiving coil is connected to one end of the rectifier filter circuit (7), the other end of the first secondary compensation capacitor is connected to the other end of the rectifier filter circuit (7), one end of the second secondary receiving coil is connected to one end of the rectifier filter circuit (7), the other end of the second secondary receiving coil is connected to one end of the second secondary series compensation capacitor, the other end of the second secondary series compensation capacitor is connected to one end of the second secondary parallel compensation capacitor, and both are connected to one end of the second secondary compensation inductor, the other end of the second secondary parallel compensation capacitor is connected to one end of the rectifier filter circuit (7), and the other end of the second secondary compensation inductor is connected to the other end of the rectifier filter circuit (7).

5. The hybrid compensation topology structure with anti-offset constant current according to claim 1, characterized in that: The first primary transmitting coil and the first secondary receiving coil are mutual inductance coils at the same end, and the second primary transmitting coil and the second secondary receiving coil are mutual inductance coils at the same end.

6. The hybrid compensation topology structure with anti-offset constant current according to claim 1, characterized in that: The output port of the first secondary receiving circuit (5) and the output port of the second secondary receiving circuit (6) are connected in parallel to form a combined hybrid compensation topology output port, and the output current of the first secondary receiving circuit (5) and the output current of the second secondary receiving circuit (6) together provide input current for the rectifier filter circuit (7).

7. The hybrid compensation topology structure with anti-offset constant current according to claim 1, characterized in that: The first primary transmitting coil, the second primary transmitting coil, the first secondary receiving coil and the second secondary receiving coil are all wound on a magnetic core using Litz wire, and the magnetic core is made of magnetic conductive material.

8. A method for constructing parameters of a hybrid compensation topology structure with an anti-offset constant current, characterized in that: Using the anti-offset constant current hybrid compensation topology structure described in any one of claims 1 to 7, the method comprises the following steps: Step 1: Determine the system operating frequency according to actual needs 、DC power supply (1) voltage , Input voltage , output current , load (8); Step 2: Determine the first primary transmitting coil , the second primary transmitting coil , the first secondary receiving coil and the second secondary receiving coil The self-inductance, the first primary transmitting coil With the first secondary receiving coil Mutual inductance , the second primary transmitting coil With the second secondary receiving coil Mutual inductance ; Step 3: According to the requirements of system resonance, write Kirchhoff's Voltage Law equation for the first compensation topology circuit and the second compensation topology circuit. The equation is as follows: （1）； （2）； In the formula is the first primary compensation inductor, is the first primary parallel compensation capacitor, is the first primary series compensation capacitor, is the first secondary compensation capacitor, For the second primary compensation inductor, is the second primary parallel compensation capacitor, is the second primary series compensation capacitor, The second secondary side series compensation capacitor is connected. is the parallel compensation capacitor of the second secondary side, For the second secondary compensation inductor, is the imaginary number symbol, is the input current of the first primary transmitting circuit (3), is the input current of the second primary transmitting circuit (4), is the current flowing through the first primary transmitting coil, is the current flowing through the second primary transmitting coil, is the current flowing through the first secondary receiving coil, is the current flowing through the second secondary receiving coil, is the output current of the second secondary receiving circuit (6), is the angular frequency, is the equivalent load; The current expressions of each branch of the first compensation topology circuit can be solved as follows: （3）； definition is the adjustment factor, which is defined as follows: （4）； definition is the first influencing parameter, is the second influencing parameter, and its expression is as follows: （5）； The second compensation topology circuit satisfies the following conditions: （6）； It can be solved that the second compensation topology circuit is obtained in and The expression is as follows: （7）； Step 4: From formula (3), we can know that if the output current of the first compensation topology circuit is Regardless of the load, the first compensation topology circuit must satisfy the following equation to satisfy the ZPA input: （8）； The currents of the first compensation topology circuit that satisfies the above equation are: （9）； Then the output current It can be expressed as: （10）； When the system is offset, the mutual inductance of the coils of the two compensation topology circuits will decrease accordingly. Obviously, it can be seen from the above formula that the output current gain is inversely proportional to the first compensation topology circuit and proportional to the second compensation topology circuit. If the mutual inductance of the coils changes too much, the output current of the first compensation topology circuit will increase sharply. Therefore, introducing an adjustment factor to adjust the equivalent mutual inductance can prevent the problem of excessive changes in the output current of the first compensation topology circuit. Step 5: Combine the actual system coil parameters and then through reasonable parameter design, the adjustment factor can be determined. Therefore, the values ​​of each compensation capacitor can be obtained as follows: （11）。

Images