Wide-range constant current output method and system for wireless power supply system based on five-switch bridge topology

Abstract

The invention relates to the field of wireless power transmission, and particularly discloses a wide-range constant current output method and system for a wireless power supply system based on five-switch bridge topology. Aiming at the problems that the adjustment range of a traditional full-bridge inverter is limited when a load changes, and wide-range constant current output is difficult to realize, the system adopts a five-switch bridge inverter as a core topology and comprises two primary side transmitting modules and two secondary side energy pickup modules. By switching four working modes of the five-switch bridge inverter, the output current of the system is in a linear proportional relation of 1: 2: 3: 4, so that wide-range constant current output can be realized only by mode switching. The method comprises the steps of designing five-switch bridge topology and parameters, deducing an output current expression in each mode, optimizing coil mutual inductance and compensation capacitance, and verifying constant current characteristics through simulation and experiments. Complex communication and control mechanisms are not needed, and the problem that a traditional system is insufficient in output adjusting capacity is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless power transmission, and provides a wide-range constant current output method and system for a wireless power supply system based on a five-switch bridge topology. Background Art

[0002] Wireless power transfer (WPT) technology, due to its safety, reliability, ease of use, and flexibility, has been widely adopted in various fields, including consumer electronics, e-mobility, and medical devices, demonstrating promising development prospects. With the continuous development of WPT technology, inductive power transfer (IPT) has attracted widespread attention due to its advantages such as stable transmission performance and flexible and easy system parameter design, becoming a research hotspot in the WPT field. Currently, full-bridge inverters are commonly used as the main circuit topology in IPT systems. Despite their simple structure and mature control methods, their single operating mode makes it difficult to adapt to load fluctuations, resulting in a limited regulation range and insufficient output control capability. This limitation restricts overall system performance and poses challenges for system optimization. On the other hand, constant current power supplies are widely used in applications requiring high current stability, such as battery charging, LED driving, medical equipment, and industrial control. Achieving a stable constant current output over a wide range, especially under conditions of large load fluctuations, is crucial for ensuring operational stability, safety, and extending the life of the equipment. Therefore, how to achieve stable and reliable constant current power supply with wide range output characteristics in IPT system has become one of the key issues that need to be solved urgently in this field. Summary of the Invention

[0003] The purpose of the present invention is to solve the technical problem that the traditional wireless power supply system has a limited adjustment range due to a single working mode and is difficult to achieve a wide range constant current output.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical means:

[0005] The present invention provides a wireless power supply system based on a five-switch bridge topology, comprising:

[0006] DC voltage source E I ;

[0007] The five-switch bridge inverter consists of five switching devices Q1 to Q5, and has three output nodes a, b, and c.

[0008] The first primary transmitting module: DD transmitting coil L connected in series P1 and the first compensation capacitor C P1 , connected between node a and node b;

[0009] Second primary transmitting module: Q transmitting coils L connected in series P2 and the second compensation capacitor C P2 , connected between node b and node c;

[0010] The first secondary energy pickup module: DD receiving coil L connected in series S1 and the third compensation capacitor C S1 , through the first rectifier bridge composed of four diodes D1 to D4 and the first filter capacitor C 01 Output;

[0011] Second secondary energy pickup module: Q receiving coil L connected in series S2 and the fourth compensation capacitor C S2 , through the second rectifier bridge composed of four diodes D5 to D8 and the second filter capacitor C O2 Output;

[0012] Load end: The DC output ends of the first rectifier bridge and the second rectifier bridge are connected in parallel and connected to the load resistor R0;

[0013] The mutual inductance M1 between the DD transmitting coil and the DD receiving coil is equal to the mutual inductance M2 between the Q transmitting coil and the Q receiving coil.

[0014] In the above technical solution, the five-switch bridge inverter is configured to switch between four operating modes:

[0015] Mode 1: The switch tube Q3 maintains a continuous conduction state, while Q2 and Q4 are always kept off, and Q1 and Q5 are alternately turned on in a complementary manner with a certain dead time, and the output current

[0016] Mode 2: Switches Q1 and Q3 maintain a continuous on state, while Q5 remains off. Q2 and Q4 are alternately turned on in a complementary manner with a certain dead time, and the output current

[0017] Mode 3: The switch tube Q3 maintains a continuous conduction state, while "Q1 and Q4" and "Q2 and Q5" are alternately turned on in a complementary manner with a certain dead time, and the output current

[0018] Mode 4: The switch tube Q5 maintains a continuous conduction state, while "Q1 and Q4" and "Q2 and Q3" are alternately turned on in a complementary manner with a certain dead time, and the output current

[0019] Among them, ω0 is the resonant angular frequency, M1=M2=M, and the output current ratio of the four modes is 1:2:3:4.

[0020] In the above technical solution, the compensation capacitor C P1 , C P2 , C S1 , C S2 Satisfy the resonance condition:

[0021]

[0022] Where ω0 is the system operating angular frequency, and j represents the imaginary unit.

[0023] The present invention provides a wide-range constant current output method for a wireless power supply system based on a five-switch bridge topology, comprising the following steps:

[0024] Step 1: Construct the wireless power supply system topology and switch the working mode through the five-switch bridge inverter;

[0025] Step 2: Based on the different operating modes of the five-switch bridge inverter, establish the corresponding equivalent circuit and solve the KVL equations;

[0026] By inputting the zero phase angle ZPA condition, the coil loops on both the primary and secondary sides are in a resonant state;

[0027] Substituting the resonance condition into the KVL equations, the primary and secondary current expressions are derived, and the mapping relationship between the output current and the operating mode is obtained;

[0028] Step 3: Determine the input voltage E I , operating frequency f, target maximum output current I Omax , according to the output current of mode 4, that is, according to the target maximum output current I Omax Calculate the target mutual inductance value M, and design the wire diameter, number of turns, and core structure of the D / Q coils based on the M value;

[0029] Determine the coil self-inductance L using simulation tools P1 , L P2 , L S1 , L S2 And compensation capacitor C P1 、C P2 、C S1 、C S2 ;

[0030] Step 4: Verify the output current proportional relationship and constant current characteristics of the system in different modes through simulation and experiments.

[0031] In the above scheme, step 2 includes the mapping relationship between the output current and the working mode:

[0032]

[0033] Where ω0 is the system operating angular frequency.

[0034] In the above solution, the mutual inductance M is calculated according to the output current formula of mode 4:

[0035]

[0036] In the above scheme, the compensation capacitance is calculated according to the resonance condition:

[0037]

[0038] Because the present invention adopts the above technical means, it has the following beneficial effects:

[0039] 1. The present invention adopts a five-switch bridge inverter composed of five switching devices and its four operating mode switching mechanism to solve the problem of limited output adjustment range caused by the single operating mode of traditional full-bridge inverters. It can achieve the effect of expanding the output current range according to the ratio of 1:2:3:4 without the need for additional communication and control circuits, and significantly improve the load adaptability of the system.

[0040] 2. The present invention is based on the modal switching mechanism and resonance condition design of the five-switch bridge inverter (i.e., satisfying This solves the problem of constant current output stability in multi-coil coupling systems, achieves the effect of maintaining load-independent constant current output characteristics under any load conditions, and ensures power supply reliability in application scenarios such as battery charging and LED driving.

[0041] 3. This invention addresses the technical issue of output current imbalance when multiple transmission channels work together by requiring the mutual inductance of the DD and Q coils to be equal (i.e., M1 = M2) and adopting a parallel secondary-side rectifier output structure. This achieves precise proportional current output in four modes through hardware topology design alone, significantly simplifying system complexity and control difficulty.

[0042] 4. The present invention designs the mutual inductance parameters based on the mapping relationship between the output current and the mode, which solves the problem of difficult parameter matching in a wide range constant current system, and achieves the effect of reversely deducing the coil parameters (wire diameter, number of turns, magnetic core) based on the target maximum output current, thereby improving the predictability and engineering applicability of the system design. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is the equivalent circuit of the wireless power supply system based on the five-switch bridge topology.

[0044] Figure 2 It is the equivalent circuit of the four operating modes of the five-switch bridge inverter;

[0045] Figure 3This is the equivalent circuit of a wireless power supply system based on a five-switch bridge topology operating in mode l.

[0046] Figure 4 It is the equivalent circuit of a wireless power supply system based on a five-switch bridge topology operating in mode 2 / 3 / 4.

[0047] Figure 5 This is a flow chart for parameter design of a wireless power supply system based on a five-switch bridge topology.

[0048] Figure 6 It is a simulation model of a wireless power supply system based on a five-switch bridge topology.

[0049] Figure 7 It is an experimental prototype of a wireless power supply system based on a five-switch bridge topology.

[0050] Figure 8 This is the simulation result of the wide-range constant current output of the wireless power supply system based on the five-switch bridge topology.

[0051] Figure 9 This is the experimental result of wide-range constant current output of a wireless power supply system based on a five-switch bridge topology. DETAILED DESCRIPTION

[0052] The following is a detailed description of the embodiments of the present invention. Although the present invention will be described and illustrated in conjunction with certain specific embodiments, it should be noted that the present invention is not limited to these embodiments. On the contrary, modifications or equivalent substitutions of the present invention are intended to fall within the scope of the claims of the present invention.

[0053] In addition, in order to better illustrate the present invention, numerous specific details are given in the following detailed description. It will be understood by those skilled in the art that the present invention can also be implemented without these specific details.

[0054] In response to the shortcomings of the above-mentioned background technology, the present invention proposes a wireless power supply system based on a five-switch bridge topology. The system can operate in four different working modes, and the output current sizes working in modes 1 to 4 show a ratio of 1:2:3:4. Therefore, a wide range of constant current output can be achieved only by mode switching without the need for complex communication and control mechanisms.

[0055] The present invention adopts the following technical solutions to achieve the above-mentioned purpose:

[0056] 1. Product invention:

[0057] 1. Description of product connection and structure:

[0058] This invention discloses a wireless power supply system based on a five-switch bridge topology. This system, which belongs to the field of wireless power transmission, aims to address the difficulty of achieving wide-range constant current output in traditional wireless power supply systems. The system primarily consists of two primary-side transmitting modules and two secondary-side energy pickup modules.

[0059] The equivalent circuit of the wireless power supply system based on the five-switch bridge topology is as follows: Figure 1 As shown in FIG, the wireless power supply system uses two sets of DDQ coil structures as energy transmission units. The two primary transmitting modules share a DC voltage source E. I A five-switch bridge inverter is formed by five NMOS power devices Q1 to Q5, and the inverter has three output nodes a, b, and c.

[0060] Specifically, the power supply E I The positive electrode is electrically connected to the drain of Q1 and Q2, and the power supply E I The negative electrode is electrically connected to the source of Q3 and Q4;

[0061] The source of Q1 is electrically connected to the drain of Q5, and an output node a is derived between the source of Q1 and the drain of Q5;

[0062] The source of Q5 is electrically connected to the drain of Q3, and an output node c is derived between the source of Q5 and the drain of Q3;

[0063] The source of Q2 is electrically connected to the drain of Q4, and an output node b is derived between the source of Q2 and the drain of Q4;

[0064] The two primary transmission modules include a first primary transmission module and a second primary transmission module. The first primary transmission module includes a DD transmission coil L P1 and its series compensation capacitor C P1 , the connection path is: inverter output node a→C P1 →L P1 →Output node b, forming a closed loop.

[0065] The second primary transmitting module includes a Q transmitting coil L P2 and its series compensation capacitor C P2 , the connection path is: inverter output node b→C P2 →L P2 →Output node c, forming another closed loop.

[0066] The two secondary energy pickup modules include a first secondary energy pickup module and a second secondary energy pickup module, and are coupled to the two primary transmitting modules respectively. The first secondary energy pickup module includes a DD receiving coil L S1 , compensation capacitor C S1 The first rectifier consists of four diodes D1 to D4 and a filter capacitor C01 , where L S1 with C S1 The second secondary energy pickup module includes a Q receiving coil L S2 , compensation capacitor C S2 The second rectifier consists of four diodes D5 to D8 and a filter capacitor C O2 , where L S2 with C S2 After being connected in series, they are connected to the AC input terminals f and g of the second rectifier bridge to form a closed loop. The DC output terminals of the first rectifier and the second rectifier are connected through filter capacitors C 01 , filter capacitor C 02 After filtering, they are connected in parallel and connected to the load resistor R0.

[0067] Among them, I 01 and I 02 They represent the output currents of the two sets of rectifiers respectively. The output current, i.e. the current flowing through the resistor, is I0, and the output voltage, i.e. the voltage across the resistor, is U0. P1 and I S1 Respectively represent the current flowing through the primary and secondary DD coils, I P2 and I S2 They represent the current flowing through the primary and secondary Q coils respectively, and M1 and M2 represent the mutual inductance between the primary and secondary DD coils and the primary and secondary Q coils respectively.

[0068] 2. Working principle description:

[0069] The equivalent circuits of the four operating modes of the five-switch bridge inverter are as follows: Figure 2 As shown in Table 1, the fundamental harmonic analysis (FHA) method is used to analyze the fundamental effective value of the inverter bridge output voltage under different working modes.

[0070] Since the wireless power supply system directly inherits the topological characteristics of the inverter, its working mode also forms a one-to-one correspondence with it. The wireless power supply system uses a series connection method for energy transmission in the two primary coils only in mode 1. In the other three modes, the primary coils all maintain an independent energy transmission state. In order to simplify the calculation, the present invention uses FHA to analyze each working mode. Considering that under the action of high-frequency alternating current, the impedance of the coil is much greater than its parasitic resistance, the parasitic resistance of the coil is ignored when modeling the circuit, and the focus is on analyzing its circuit characteristics. The equivalent circuit of the wireless power supply system based on the five-switch bridge topology working in mode 1 is as follows Figure 3 As shown, the equivalent circuit of the system working in mode 2 / 3 / 4 is as follows Figure 4 shown.

[0071] Table 1 Fundamental RMS value of the bridge voltage at the five-switch bridge inverter

[0072]

[0073] According to FHA:

[0074]

[0075] where R O1 and R O2 are the equivalent resistance of the DC side of the rectifier bridge, R eq1 and R eq2 R O1 and R O2 The AC equivalent resistance, U de and U fg is the fundamental RMS value of the rectifier midpoint voltage. Define ω as the switching angular frequency and ω0 as the resonant angular frequency.

[0076] Then there is

[0077]

[0078] Substituting formula (1) into formula (2) yields:

[0079]

[0080] According to Figure 1 Can be obtained:

[0081]

[0082] Then the output current I0 can be expressed as:

[0083]

[0084] a. Modal l

[0085] according to Figure 3 , from KVL we can get:

[0086]

[0087] The equivalent impedance of each node in the circuit is:

[0088]

[0089] To ensure the ZPA conditions of input voltage and current, the input impedance should be resistive, which should satisfy:

[0090]

[0091] Substituting formula (8) into formula (7) yields the equivalent impedance of each node in the circuit at the resonant frequency:

[0092]

[0093] Substituting formula (7) into formula (6) we can get the primary-secondary current:

[0094]

[0095] From the equivalent circuit, we can see that:

[0096]

[0097] Substituting formula (11) into formula (10) yields:

[0098]

[0099] That is, the mutual inductance of the two sets of coils needs to be equal, so:

[0100] M1=M2=M (13)

[0101] Substituting formula (13) into formula (10) yields:

[0102]

[0103] According to formula (5), I0 can be obtained:

[0104]

[0105] The five-switch bridge inverter in Table 1 is operated in mode 1. ac Substituting the value of , we can get:

[0106]

[0107] b. Mode 2 / 3 / 4

[0108] according to Figure 4 From KVL we can know that:

[0109]

[0110] The equivalent impedance of each node in the circuit is:

[0111]

[0112] To ensure the ZPA conditions of input voltage and current, the input impedance should be resistive, which should satisfy:

[0113]

[0114] Substituting formula (19) into formula (18) yields the equivalent impedance of each node in the circuit at the resonant frequency:

[0115]

[0116] Substituting formula (20) into formula (17) can obtain the primary-secondary current:

[0117]

[0118] According to formula (5), I0 can be obtained:

[0119]

[0120] The five-switch bridge inverter in Table 1 is operated in mode 2, mode 3, and mode 4. ab 、U bc Substituting the values ​​of into the equation, we can get:

[0121]

[0122] To maintain consistency, let the mutual inductance of the two sets of coils be equal. Substituting formula (13) into it, we can get:

[0123]

[0124] In summary, the wireless power supply system operating in mode 1 requires that the mutual inductance of the two coils be equal. Therefore, when configuring subsequent parameters, it is necessary to ensure that the mutual inductance between the DD coils is equal to the mutual inductance between the Q coils. On this basis, the output current of the wireless power supply system operating in various modes can be summarized in Table 2.

[0125] Table 2 Output current of wireless power supply system based on five-switch bridge topology

[0126]

[0127] As can be seen from Table 2, the wireless power supply system based on the five-switch bridge topology proposed in this paper has a load-independent constant current output characteristic, and the output current is different in different working modes. The output current values ​​of mode 1, mode 2, mode 3 and mode 4 have a ratio of 1:2:3:4, that is, the system can achieve a wide range of constant current output through mode switching.

[0128] 2. Method Inventions:

[0129] The present invention proposes a wide-range constant current output method for a wireless power supply system based on a five-switch bridge topology. The steps for implementing the method are as follows:

[0130] Step 1: Design the system topology. Figure 1As shown in the figure, the wireless power supply system based on the five-switch bridge topology consists of two primary-side transmitting modules and two secondary-side energy pickup modules. Since the five-switch bridge inverter has three output nodes, the two primary-side transmitting modules can share one inverter, and the two secondary-side energy pickup modules are connected in parallel to supply power to the load resistor. The system can achieve load-independent current output in each working mode. By switching the working mode of the five-switch bridge inverter, the output current can be changed, so a wide range of constant current output can be achieved. The system mainly includes a five-switch bridge inverter, a DD transmitting coil L P1 and its series compensation capacitor C P1 , Q transmitting coil L P2 and its series compensation capacitor C P2 ,DD receiving coil L S1 and its series compensation capacitor C S1 , Q receiving coil L S2 and its series compensation capacitor C S2 , rectifier bridge 1 and its filter capacitor C O1 , rectifier bridge 2 and its filter capacitor C 02 And load resistor R0. DD transmitting coil L Pl and DD receiving coil L P2 The mutual inductance between the transmitting coils is M1, Q and L P1 and Q receiving coil L P2 The mutual inductance between them is M2.

[0131] Step 2: Theoretically derive the proposed circuit topology. First, draw the equivalent circuits under different working modes, and write the KVL equations according to the equivalent circuits. Based on the circuit derivation, the resonance condition of the input ZPA can be realized, that is, the condition that all four coil loops of the primary and secondary sides can achieve resonance. Substituting the resonance condition into the KVL equations, the current expression in the primary and secondary coils can be obtained, and finally the output current expression can be obtained. The feasibility and effectiveness of the wide-range constant current output method can be theoretically achieved through mode switching in the wireless power supply system based on the five-switch bridge topology. Finally, the output current expression under each working mode is obtained:

[0132]

[0133] Step 3: Design the system parameters. Figure 5 The system parameters are designed by following the flowchart shown in the figure. First, the system input DC voltage E is determined. I , operating frequency f, maximum output current, i.e., the output current I when the system operates in mode 4 Omax , thereby determining the mutual inductance M and obtaining the maximum primary and secondary current, that is, the primary and secondary current I when the system works in mode 4 P1max , I P2max , I S1max , IS2max Based on this, we choose the wire material specifications for the coil, then determine the outer diameter of the coil and the size and specifications of the core. In Maxwell, we simulate and determine the number of coil turns and transmission distance to get the closest to the mutual inductance determined above, thereby determining the self-inductance of each coil. Finally, we calculate the resonant compensation capacitance of each coil according to the input ZPA conditions. At this point, the system parameter design is complete.

[0134] Step 4: Evaluate the performance of the circuit topology. Build a simulation model of the system in MATLAB / Simulink based on the equivalent circuit and the system parameters designed in step 3. Figure 6 As shown, the experimental prototype is built as Figure 7 As shown, simulation analysis and experimental verification are then carried out to verify the feasibility and effectiveness of the method of achieving wide-range constant current output through mode switching in a wireless power supply system based on a five-switch bridge topology.

[0135] Example 1

[0136] The wide-range constant current output method of the wireless power supply system based on the five-switch bridge topology proposed in this patent is illustrated by taking the wide-range constant current output with a maximum output current of 2A as an example. The specific implementation method is as follows:

[0137] Step 1: Design the system topology. Figure 1 As shown in the figure, the wireless power supply system based on the five-switch bridge topology consists of two primary-side transmitting modules and two secondary-side energy pickup modules. Since the five-switch bridge inverter has three output nodes, the two primary-side transmitting modules can share one inverter, and the two secondary-side energy pickup modules are connected in parallel to supply power to the load resistor. The system can achieve load-independent current output in each working mode. By switching the working mode of the five-switch bridge inverter, the output current can be changed, so a wide range of constant current output can be achieved. The system mainly includes a five-switch bridge inverter, a DD transmitting coil L P1 and its series compensation capacitor C P1 , Q transmitting coil L P2 and its series compensation capacitor C P2 ,DD receiving coil L S1 and its series compensation capacitor C S1 , Q receiving coil L S2 and its series compensation capacitor C S2 , rectifier bridge 1 and its filter capacitor C O1 , rectifier bridge 2 and its filter capacitor C O2 And load resistor R0. DD transmitting coil L P1 and DD receiving coil L P2 The mutual inductance between them is M l , Q transmitting coil L P1 and Q receiving coil LP2 The mutual inductance between them is M2.

[0138] Step 2: Theoretical derivation of the proposed circuit topology.

[0139] according to Figure 3 The equivalent circuit of the system shown in mode l can obtain the KVL equations:

[0140]

[0141] according to Figure 4 The equivalent circuit of the system shown in Figure 2 works in mode 2 / 3 / 4, and the KVL equations can be obtained:

[0142]

[0143] And according to the circuit characteristics:

[0144] M1=M2=M(28)

[0145] The resonance condition for the system to achieve input ZPA is obtained:

[0146]

[0147] The primary and secondary current expressions of the system in working mode l are derived as follows:

[0148]

[0149] The primary and secondary current expressions of the system in working mode 2 / 3 / 4 are derived as follows:

[0150]

[0151] The output current expression under each working mode is derived:

[0152]

[0153] Step 3: Design the system parameters. Figure 5 The system parameters are designed according to the flowchart shown.

[0154] 1. Determine the system input DC voltage E I , operating frequency f, maximum output current, i.e., the output current I when the system operates in mode 4 Omax :

[0155] E I =24V,f=200kHz,I Omax =2A (33)

[0156] ω0=2πf(34)2. Determine the mutual inductance M. Combining formulas (32), (33) and (34) yields:

[0157] M=15.48μH(35)

[0158] 3. Obtain the maximum primary and secondary current, that is, the primary and secondary current I when the system operates in mode 4. PImax , I P2max , I Slmax , I S2max :

[0159] From formula (31), we can know that if we want to find I PImax , I P2max Need to ask R eq1 、R eq2 , combining formula (3), formula (11) and formula (31) to obtain

[0160]

[0161] From formula (36), we can know that R eq1 、R eq2 It is proportional to R0, so let the maximum load of the system be R Omax for:

[0162] R Omax =30Ω (37)

[0163] By combining formula (31), formula (33), formula (34), formula (36), formula (37) and formula (38), and substituting the fundamental effective value of the output voltage of the five-switch bridge inverter under mode 4 in Table 1 into the formula, we can obtain:

[0164] I P1max =I P2max =2.78A, I S1max =I S2max =1.11A (38)

[0165] 4. Choose coil wire rules:

[0166] The coil wire is usually made of high-frequency Litz wire. According to the manufacturer's data sheet, a 0.1mm*200-strand high-frequency Litz wire with a current resistance of 7.85A is used, and its outer diameter is 1.98mm.

[0167] 5. Determine coil size and core specifications:

[0168] The primary and secondary coils both use DDQ coils. Both the DD coil and the Q coil are rectangular with a length of 200mm and a width of 100mm. The magnetic core is made of two square PC95 pieces with a side length of 100mm and a thickness of 5mm.

[0169] 6. Simulate in Maxwell to determine the number of coil turns and transmission distance:

[0170] First, the transmission distance is determined to be 50 mm. Then, by adjusting the number of coil turns in the simulation, the target mutual inductance value given in formula (35) is gradually approached. Since the DD and Q coils have been decoupled, the change in the number of turns of the DD coil will not affect the mutual inductance between the Q coils. Similarly, the change in the number of turns of the Q coil will not affect the mutual inductance between the DD coils. In Maxwell, the number of turns of the DD coil and the Q coil are swept from 10 turns to 17 turns, stepping 1 turn, to obtain the corresponding mutual inductance data. The simulation results show that when the number of turns of the DD coil is 14, the mutual inductance is 15.09 μH, which is closest to the target mutual inductance value. When the number of turns of the Q coil is 16, the mutual inductance is 15.37 μH, which is closest to the target mutual inductance value.

[0171] 7. Determine the self-inductance L of each coil P1 , L P2 , L S1 , L S2 :

[0172] Set the number of turns of the DD coil to 14 and the number of turns of the Q coil to 16, and re-run the simulation in Maxwell to obtain the self-inductance value L of each coil. P1 , L P2 , L S1 , L S2 :

[0173] L P1 =74.88μH, L P2 =65.88μH, L S1 =74.83μH, L S2 =65.91μH (39)

[0174] The simulation results also show that the mutual inductance between the primary DD coil and the primary Q coil, the primary DD coil and the secondary Q coil, the secondary DD coil and the primary Q coil, and the secondary DD coil and the secondary Q coil are all at the nanohenry level, indicating that decoupling has been achieved between the primary DD coil and the primary-secondary Q coil, and between the secondary DD coil and the primary-secondary Q coil.

[0175] 8. Determine the compensation capacitance C of each coil P1 、C P2 、C S1 、C S2 , substituting formula (39) into formula (29), we can get:

[0176] C P1 =8.46nF,C P2 =9.61nF,C S1=8.46nF,C S2 =9.61nF (40)

[0177] In summary, the system parameters can be summarized in Table 3.

[0178] Table 3 System parameters

[0179]

[0180] Step 4: Evaluate the performance of the circuit topology. Build a simulation model of the system in MATLAB / Simulink based on the equivalent circuit and the system parameters designed in step 3. Figure 6 As shown, the system is operated in four working modes respectively, and the load resistance is increased from 5Ω to 30Ω at a time. The output current under each load condition is recorded, and the output current change curve is drawn as shown in FIG. Figure 8 As shown. And build the experimental prototype as shown Figure 7 As shown, the system is operated in four modes respectively, and the load resistance value is gradually adjusted, starting from 1Ω and increasing by 1Ω each time until 25Ω. The output current under each load condition is recorded, and the curve of output current changing with load is drawn as shown in the figure. Figure 9 As shown in Figure 2 , both simulation and experimental results show that as the load resistance increases, the output power increases and the output current decreases slightly, resulting in a good overall constant-current output characteristic for the system. Furthermore, the system's maximum output current is approximately 2A, meeting the design goal. Furthermore, the output currents of modes 1 through 4 exhibit an approximate ratio of 1:2:3:4. This demonstrates the feasibility and effectiveness of achieving a wide-range constant-current output through mode switching in a wireless power supply system based on a five-switch bridge topology, both from simulation and experimental perspectives.

Claims

1. A wireless power supply system based on a five-switch bridge topology, characterized in that: include: DC voltage source E I ; A five-switch bridge inverter consisting of five switching devices Q1 to Q5 has three output nodes a, b, and c; The first primary transmitting module: DD transmitting coil L connected in series P1 and the first compensation capacitor C P1 , connected between node a and node b; Second primary transmitting module: Q transmitting coils L connected in series P2 and the second compensation capacitor C P2 , connected between node b and node c; The first secondary energy pickup module: DD receiving coil L connected in series S1 and the third compensation capacitor C S1 , through the first rectifier bridge composed of four diodes D1 to D4 and the first filter capacitor C 01 Output; Second secondary energy pickup module: Q receiving coil L connected in series S2 and the fourth compensation capacitor C S2 , through the second rectifier bridge composed of four diodes D5 to D8 and the second filter capacitor C O2 Output; Load end: The DC output ends of the first rectifier bridge and the second rectifier bridge are connected in parallel and connected to the load resistor R0; The mutual inductance M1 between the DD transmitting coil and the DD receiving coil is equal to the mutual inductance M2 between the Q transmitting coil and the Q receiving coil.

2. The wireless power supply system according to claim 1, wherein: Power Supply E I The positive electrode is electrically connected to the drain of Q1 and Q2, and the power supply E I The negative electrode is electrically connected to the source of Q3 and Q4; The source of Q1 is electrically connected to the drain of Q5, and an output node a is derived between the source of Q1 and the drain of Q5; The source of Q5 is electrically connected to the drain of Q3, and an output node c is derived between the source of Q5 and the drain of Q3; The source of Q2 is electrically connected to the drain of Q4 , and an output node b is derived between the source of Q2 and the drain of Q4 .

3. The wireless power supply system according to claim 2, wherein: The five-switch bridge inverter is configured to switch between four operating modes: Mode 1: Switch Q3 maintains a continuous conduction state, while Q2 and Q4 remain in the off state, and Q1 and Q5 are alternately turned on in a complementary manner with dead time, and the output current Mode 2: Switches Q1 and Q3 maintain a continuous on state, while Q5 remains off. Q2 and Q4 are turned on alternately in a complementary manner with dead time, and the output current Mode 3: Switch Q3 maintains a continuous conduction state, while "Q1 and Q4" and "Q2 and Q5" are alternately turned on in a complementary manner with dead time, and the output current Mode 4: Switch Q5 maintains a continuous conduction state, while "Q1 and Q4" and "Q2 and Q3" are alternately turned on in a complementary manner with a certain dead time, and the output current Among them, ω0 is the resonant angular frequency, M1=M2=M, and the output current ratio of the four modes is 1:2:3:

4.

4. The system according to claim 1, wherein: The compensation capacitor C P1 , C P2 , C S1 , C S2 Satisfy the resonance condition: Where ω0 is the system operating angular frequency, and j represents the imaginary unit.

5. A wide range constant current output method for a wireless power supply system based on a five-switch bridge topology, characterized in that The following steps are involved: Step 1: constructing a wireless power supply system topology as described in any one of claims 1 to 3, and switching the operating mode through a five-switch bridge inverter; Step 2: Based on the different operating modes of the five-switch bridge inverter, establish the corresponding equivalent circuit and solve the KVL equations; By inputting the zero phase angle ZPA condition, the coil loops on both the primary and secondary sides are in a resonant state; Substituting the resonance condition into the KVL equations, the primary and secondary current expressions are derived, and the mapping relationship between the output current and the operating mode is obtained; Step 3: Determine the input voltage E I , operating frequency f, target maximum output current I Omax , according to the output current of mode 4, that is, according to the target maximum output current I Omax Calculate the target mutual inductance value M, and design the wire diameter, number of turns, and core structure of the DD / Q coil based on the M value; Determine the coil self-inductance L using simulation tools P1 、L P2 、L S1 、L S2 And compensation capacitor C P1 、C P2 、C S1 、C S2 ; Step 4: Verify the output current proportional relationship and constant current characteristics of the system in different modes through simulation and experiments.

6. The method according to claim 4, characterized in that: The mapping relationship between output current and working mode in step 2 is: Where ω0 is the system operating angular frequency.

7. The method according to claim 5, characterized in that: Calculate the mutual inductance M according to the output current formula of mode 4:

8. The method according to claim 5, characterized in that: Calculate the compensation capacitance according to the resonance condition:

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