A load equivalent resistance estimation method for a dual-transmit single-receive wireless charging system

Abstract

The application provides a load equivalent resistance estimation method of a double-transmitting single-receiving wireless charging system, and is used for solving the technical problem of low load resistance estimation accuracy and unstable measurement result of a wireless power transmission (WPT) system in the prior art. The specific steps are as follows: S1: constructing an impedance equation of the double-transmitting single-receiving wireless charging system and system constraint conditions, and optimizing the system impedance equation through the system constraint conditions; S2: based on the optimized impedance equation, calculating the effective values I r1 and I r2 of the currents on the two original side compensation inductors of the system and the mathematical relationship with the load resistance R L ; S3: collecting the effective values I r1 and I r2 of the currents on the two original side compensation inductors of the system and calculating the load resistance R L . The application uses a double-transmitting wireless power transmission system to estimate the load resistance, uses the effective values I r1 and I r2 of the currents on the two original side compensation inductors, estimates the resistance value of the system load, has better accuracy, and greatly improves the fault tolerance.

Description

Technical Field

[0001] This invention relates to the field of wireless power transmission, and in particular to a method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system. Background Technology

[0002] Methods for estimating load resistance in wireless power transfer (WPT) systems mainly include: Current phase detection: This method estimates load resistance by measuring the phase difference of the current in the transmission coil. The current phase changes with the load resistance, so changes in load resistance can be inferred by detecting the phase difference. Voltage measurement: Load resistance can be estimated by measuring the voltage across the transmission coil, particularly at the transformer output. This method is typically implemented using conventional voltage measurement equipment. Power transfer efficiency: This method indirectly infers changes in load resistance by monitoring the power transfer efficiency of the WPT system. Power transfer efficiency is also affected when the load resistance changes.

[0003] However, these methods all have some drawbacks: for example, they are sensitive to environmental and external conditions. Changes in external environment and conditions (such as temperature and humidity) may reduce the accuracy of these estimation methods, especially in complex electromagnetic environments where they are easily affected by interference. They also have a slow response time to load changes. Some methods respond relatively slowly to changes in load resistance, especially in high-frequency WPT systems, where rapidly changing loads may not be estimated accurately and in a timely manner. Furthermore, some methods rely on additional sensors; they may require additional sensors to measure parameters such as current and voltage, increasing system complexity and cost.

[0004] Because WPT systems often operate in complex environments, changes and uncertainties in external conditions can affect the accuracy of sensor measurements, thereby reducing the performance of the estimation method. At high frequencies, the propagation characteristics of electromagnetic waves are affected by their propagation in space, leading to instability in the measurement results. Furthermore, some WPT system designs may not have considered the impact of load variations on system performance, resulting in inherent shortcomings in practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide a method for estimating the equivalent load resistance of a dual-transmitter, single-receiver wireless charging system. This addresses the technical problems of low accuracy and unstable measurement results in the prior art for estimating the load resistance of wireless power transfer (WPT) systems.

[0006] A method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system includes the following steps:

[0007] S1: Construct the impedance equation and system constraints of the dual-transmitter single-receiver wireless charging system, and optimize the system impedance equation through the system constraints;

[0008] S2: Based on the optimized impedance equation, calculate the effective value I of the current on the two primary-side compensating inductors of the system. r1 and I r2 With load resistance R L Mathematical relationships;

[0009] S3: The effective value of the current on the two primary-side compensation inductors of the acquisition system (I) r1 and I r2 And calculate the load resistance R. L .

[0010] Preferably, in step S1, based on Kirchhoff's voltage and current laws, the impedance equation of the dual-transmitter single-receiver wireless charging system is constructed as follows:

[0011]

[0012] In the formula, L r1 L1 and L r2 L2 and L3 are the self-inductances of the two primary coils of the system, respectively, and C is the self-inductance of the secondary coil of the system. r1 C1 and C r2 C2 and C3 are the compensation capacitors for the two primary windings of the system, respectively; C3 is the compensation capacitor for the secondary winding of the system; M 13 M 23 M represents the mutual inductance between the two primary and secondary coils. 12 R is the mutual inductance between the two primary coils. r1 R1 and R r2 R1 and R2 are the equivalent internal resistances of the mutual inductance of the two primary windings of the system, respectively; R3 is the equivalent internal resistance of the secondary winding of the system; and R0 is the equivalent input impedance of the rectifier bridge of the system. and These are the AC input voltages of the two primary coils of the system, respectively. and These are the effective values ​​of the currents on the two primary winding inductors of the system, respectively. ω represents the effective value of the current in the secondary coil inductance of the system, j is the imaginary unit, and ω is the angular frequency of the system operation.

[0013] As a preferred method, the method for constructing the constraints of the dual-transmitter single-receiver wireless charging system in step S1 is as follows:

[0014] Assume the parameters of the dual-transmitter single-receiver wireless charging system are perfectly harmonic, meaning the system parameters satisfy the following equality constraints:

[0015]

[0016] As a preferred embodiment, the specific method for optimizing the system impedance equation through system constraints in step S1 is as follows:

[0017] The impedance equation for a dual-transmitter, single-receiver wireless charging system is:

[0018]

[0019] From the equality constraints of the system parameters, we can obtain:

[0020]

[0021] From the simplified impedance equation of the system with equality constraints on system parameters, we can obtain:

[0022]

[0023] Preferably, in step S2, the effective value I of the current on the two primary-side compensation inductors of the system is calculated. r1 and I r2 With load resistance R L The specific method for determining the mathematical relationship is as follows:

[0024] Based on the optimized impedance equation, the expressions for each current in the system are calculated as follows:

[0025]

[0026] The effective value I of the current on the two primary-side compensating inductors is given by the expressions for the various currents in the system. r1 and I r2 for:

[0027]

[0028] In the formula, R0 is the equivalent input impedance R of the system rectifier bridge. o =8R L / π 2 R L The system load resistance R L .

[0029] Preferably, based on the expressions for each current in the system calculated in step S2, the expression for the system output voltage can be obtained as follows:

[0030]

[0031] As can be seen from equation (7), the output voltage of the system is independent of the load resistance and the coupling inductance between the transmitter and transmitter. The output voltage of the system is controlled by adjusting the proportional factors k1 and k2.

[0032] When the system uses phase-shift control, then:

[0033]

[0034] In the formula: E dc This refers to the DC input voltage of the system.

[0035] By employing the equivalent input voltage under phase-shift control, the effective value I of the current on the two primary-side compensation inductors is... r1 and I r2 The expression simplifies to:

[0036]

[0037] In the formula:

[0038]

[0039] The effective value I of the current on the two primary-side compensating inductors r1 and I r2 The simplified expression yields:

[0040]

[0041] Preferably, the load resistance R is calculated in step S3. L The estimation formula is:

[0042]

[0043] In the formula, m∈[0,1] is the weighting factor, μ c This is the compensation coefficient.

[0044] Preferably, the dual-transmitter single-receiver wireless charging system includes two symmetrically arranged LCC resonant networks and one SS resonant network. The two symmetrically arranged LCC resonant networks are the two primary coils of the system, and the SS resonant network is the secondary coil of the system.

[0045] Because of the adoption of the above technical solution, the present invention has the following advantages:

[0046] 1. This application uses a dual-transmitter wireless power transfer system to estimate the load resistance, and utilizes the effective value I of the current on two primary-side compensating inductors. r1 and I r2 It can estimate the resistance of the system load with better accuracy and greatly improve the fault tolerance.

[0047] 2. The equivalent resistance estimation method described in this application allows the system to still estimate the load resistance even when a problem occurs in one primary circuit, by utilizing another normal primary circuit, thus greatly improving system redundancy. Furthermore, for a dual-transmitter, single-receiver wireless power transmission system, the effective value I of the current on the two primary-side compensating inductors... r1 and I r2 The estimated load resistances can be verified against each other, which improves the system's fault tolerance and makes it easier for technicians to test the estimation results.

[0048] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained from the following description and claims. Attached Figure Description

[0049] The accompanying drawings of this invention are described below.

[0050] Figure 1 This is a flowchart illustrating the estimation method for the equivalent load resistance of the dual-transmitter single-receiver wireless charging system of the present invention.

[0051] Figure 2 This is a schematic diagram of the circuit structure of the dual LCC-S-WPT system of the present invention.

[0052] Figure 3 This is the equivalent circuit diagram of the dual LCC-S-WPT system of the present invention.

[0053] Figure 4 This is a three-dimensional diagram of the coupling mechanism of the dual LCC-S-WPT system of the present invention.

[0054] Figure 5 This is a system simulation model in an embodiment of the present invention.

[0055] Figure 6 This is a comparison chart of the estimated load resistance calculated in the embodiments of the present invention and the actual system resistance.

[0056] Figure 4 In the middle: 1-coupling mechanism core; 2-secondary coil; 3-primary coil. Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0058] Example 1:

[0059] In high-power wireless charging scenarios, to adapt to diverse loads and maintain stable power output even when external factors cause spatial deflection of the load during charging, a single excitation unit has limited power transmission capability and faces high voltage and current stress. Employing a dual-excitation unit can improve power transmission capability while reducing voltage and current stress. Furthermore, the system exhibits better output robustness under varying parameters.

[0060] Therefore, this application provides as follows Figure 2 The illustrated wireless charging system includes a dual-transmitter, single-receiver power supply E. dc Inverter a and inverter b are connected, and the output terminals of inverter a and inverter b are respectively connected to an LCC resonant network. The two LCC resonant networks are symmetrically arranged, and the two symmetrically arranged LCC resonant networks are the two primary coils of the wireless charging system.

[0061] It also includes an SS resonant network, which is the secondary coil of the wireless charging system. The output of the SS resonant network is connected to a rectifier bridge, and the output of the rectifier bridge is connected to a load.

[0062] In this embodiment, the two symmetrical LCC resonant networks and the SS resonant network together form a tree resonant structure, which reduces the system's sensitivity to load changes and cross-coupling between coils.

[0063] In this embodiment, only the fundamental component of the system is considered. The equivalent circuit diagram of the dual LCC-S-WPT system, which consists of two LCC resonant networks and an SS resonant network, is shown below. Figure 2 The equivalent circuit diagram of the dual LCC-S-WPT system is shown below.

[0064] In this embodiment, as Figure 3 As shown, the secondary coil 2, the two overlapping primary coils 3, and the coupling mechanism core 1 constitute the coupling mechanism of the dual LCC-S-WPT system.

[0065] In this embodiment, as Figure 2 and Figure 3 As shown, L r1 L1 and L r2 L2 and L3 are the self-inductances of the two primary coils of the system, respectively, and C is the self-inductance of the secondary coil of the system. r1 C1 and C r2 C2 and C3 are the compensation capacitors for the two primary windings of the system, respectively; C3 is the compensation capacitor for the secondary winding of the system; M 13 M 23 M represents the mutual inductance between the two primary and secondary coils. 12 R is the mutual inductance between the two primary coils. r1R1 and R r2 R1 and R2 are the equivalent internal resistances of the mutual inductance of the two primary windings of the system, respectively; R3 is the equivalent internal resistance of the secondary winding of the system; R0 is the equivalent input impedance of the rectifier bridge of the system; U s1 with U s2 These are the AC input voltages of the two primary coils of the system, I. r1 , I1 and I r2 I2 and I3 are the effective values ​​of the currents on the two primary winding inductors of the system, respectively, and I3 is the effective value of the current on the secondary winding inductor of the system. 1a -S 4a For the MOSFET of inverter a, S 1b -S 4b D1-D4 are the MOSFETs of inverter b, D1-D4 are the rectifier bridge diodes, and C is the MOSFET. f For filtering capacitors; R L For load.

[0066] Example 2:

[0067] like Figure 1 The method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system, as shown, includes the following steps:

[0068] S1: Construct the impedance equation and system constraints of the dual-transmitter single-receiver wireless charging system, and optimize the system impedance equation through the system constraints; the specific steps are as follows:

[0069] S1.1: Based on Kirchhoff's voltage and current laws, the impedance equation for the dual-transmitter single-receiver wireless charging system is as follows:

[0070]

[0071] In the formula, L r1 L1 and L r2 L2 and L3 are the self-inductances of the two primary coils of the system, respectively, and C is the self-inductance of the secondary coil of the system. r1 C1 and C r2 C2 and C3 are the compensation capacitors for the two primary windings of the system, respectively; C3 is the compensation capacitor for the secondary winding of the system; M 13 M 23 M represents the mutual inductance between the two primary and secondary coils. 12 R is the mutual inductance between the two primary coils. r1 R1 and R r2 R1 and R2 are the equivalent internal resistances of the mutual inductance of the two primary windings of the system, respectively; R3 is the equivalent internal resistance of the secondary winding of the system; and R0 is the equivalent input impedance of the rectifier bridge of the system. and These are the AC input voltages of the two primary coils of the system, respectively. and These are the effective values ​​of the currents on the two primary winding inductors of the system, respectively. ω represents the effective value of the current in the secondary coil inductance of the system, j is the imaginary unit, and ω is the angular frequency of the system operation.

[0072] S1.2: Construct the constraints for the dual-transmitter single-receiver wireless charging system. Assume that the parameters of the dual-transmitter single-receiver wireless charging system are completely harmonic, that is, the system parameters satisfy the following equality constraints:

[0073]

[0074] S1.3: The specific method for optimizing the system impedance equation through system constraints is as follows:

[0075] The impedance equation for a dual-transmitter, single-receiver wireless charging system is:

[0076]

[0077] From the equality constraints of the system parameters, we can obtain:

[0078]

[0079] From the simplified impedance equation of the system with equality constraints on system parameters, we can obtain:

[0080]

[0081] S2: Based on the optimized impedance equation, calculate the effective value I of the current on the two primary-side compensating inductors of the system. r1 and I r2 With load resistance R L The mathematical relationship is as follows:

[0082] S2.1: Based on the optimized impedance equation, the expressions for each current in the system are calculated as follows:

[0083]

[0084] The effective value I of the current on the two primary-side compensating inductors is given by the expressions for the various currents in the system. r1 and I r2 for:

[0085]

[0086] In the formula, R0 is the equivalent input impedance R of the system rectifier bridge. o =8R L / π 2 R L The system load resistance R L .

[0087] S2.2: Based on the calculated expressions for each current in the system, the expression for the system output voltage can be obtained as follows:

[0088]

[0089] As can be seen from equation (7), the output voltage of the system is independent of the load resistance and the coupling inductance between the transmitter and transmitter. The output voltage of the system is controlled by adjusting the proportional factors k1 and k2.

[0090] When the system uses phase-shift control, then:

[0091]

[0092] In the formula: E dc This refers to the DC input voltage of the system.

[0093] By employing the equivalent input voltage under phase-shift control, the effective value I of the current on the two primary-side compensation inductors is... r1 and I r2 The expression simplifies to:

[0094]

[0095] In the formula:

[0096]

[0097] The effective value I of the current on the two primary-side compensating inductors r1 and I r2 The simplified expression yields:

[0098]

[0099] S3: The effective value of the current on the two primary-side compensation inductors of the acquisition system (I) r1 and I r2 And calculate the load resistance R. L Load resistance R L The estimation formula is:

[0100]

[0101] In the formula, m∈[0,1] is the weighting factor, μ c As a compensation coefficient, in this embodiment, μ c Choose 1.1.

[0102] S4 method verification:

[0103] Set the system parameters according to Table 1, and use Matlab / Simulink simulation software to build a simulation platform for simulation. The simulation system is as follows: Figure 5 As shown.

[0104] Table 1. Parameter Table of Dual LCC-S-WPT System

[0105]

[0106] The simulation results are as follows Figure 6 As shown, by Figure 6 As can be seen, the actual system resistances are given as 30Ω, 35Ω, 40Ω, 45Ω, 50Ω, 55Ω, and 60Ω, respectively. The load resistance values ​​estimated using the method described in this application are 30.91Ω, 35.59Ω, 40.34Ω, 45.52Ω, 50.84Ω, 54.5Ω, and 57.95Ω, respectively. It can be seen that the estimation algorithm is effective in the range of 30Ω to 60Ω.

[0107] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0108] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0109] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0110] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system, characterized in that, Includes the following steps: S1: Construct the impedance equation and system constraints of the dual-transmitter single-receiver wireless charging system, and optimize the system impedance equation through the system constraints; S2: Based on the optimized impedance equation, calculate the effective value I of the current on the two primary-side compensating inductors of the system. r1 and I r2 With load resistance R L Mathematical relationships; S3: The effective value of the current on the two primary-side compensation inductors of the acquisition system (I) r1 and I r2 And calculate the load resistance R. L ; In step S1, based on Kirchhoff's voltage and current laws, the impedance equation for the dual-transmitter single-receiver wireless charging system is constructed as follows: （1） In the formula, L r1 L1 and L r2 L2 and L3 are the self-inductances of the two primary coils of the system, respectively, and C is the self-inductance of the secondary coil of the system. r1 C1 and C r2 C2 and C3 are the compensation capacitors for the two primary windings of the system, respectively; C3 is the compensation capacitor for the secondary winding of the system; M 13 M 23 M represents the mutual inductance between the two primary and secondary coils. 12 R is the mutual inductance between the two primary coils. r1 R1 and R r2 R1 and R2 are the equivalent internal resistances of the mutual inductance of the two primary windings of the system, respectively; R3 is the equivalent internal resistance of the secondary winding of the system; and R0 is the equivalent input impedance of the rectifier bridge of the system. and These are the AC input voltages of the two primary coils of the system, respectively. , and , These are the effective values ​​of the currents on the two primary winding inductors of the system, respectively. This represents the effective value of the current in the secondary winding inductor of the system. The imaginary unit, The angular frequency at which the system operates; The method for constructing the constraints of the dual-transmitter single-receiver wireless charging system in step S1 is as follows: Assume the parameters of the dual-transmitter single-receiver wireless charging system are perfectly harmonic, meaning the system parameters satisfy the following equality constraints: （2）。 2. The method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system as described in claim 1, characterized in that, The specific method for optimizing the system impedance equation through system constraints in step S1 is as follows: The impedance equation for a dual-transmitter, single-receiver wireless charging system is: （3） From the equality constraints of the system parameters, we can obtain: （4） From the simplified impedance equation of the system with equality constraints on system parameters, we can obtain: （5）。 3. The method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system as described in claim 2, characterized in that, In step S2, the effective value I of the current on the two primary-side compensating inductors of the system is calculated. r1 and I r2 With load resistance R L The specific method for determining the mathematical relationship is as follows: Based on the optimized impedance equation, the expressions for each current in the system are calculated as follows: （6） The effective value I of the current on the two primary-side compensating inductors is given by the expressions for the various currents in the system. r1 and I r2 for: （7） In the formula, R0 is the equivalent input impedance R of the system rectifier bridge. o =8R L / π 2 R L The system load resistance R L .

4. The method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system as described in claim 3, characterized in that, Based on the expressions for each current in the system calculated in step S2, the expression for the system output voltage can be obtained as follows: （8） As can be seen from equation (7), the output voltage of the system is independent of the load resistance and the coupling inductance between the transmitter and transmitter. The output voltage of the system is controlled by adjusting the proportional factors k1 and k2. When the system uses phase-shift control, then: （9） In the formula: This refers to the DC input voltage of the system. By employing the equivalent input voltage under phase-shift control, the effective value I of the current on the two primary-side compensation inductors is... r1 and I r2 The expression simplifies to: （10） In the formula: The effective value I of the current on the two primary-side compensating inductors r1 and I r2 The simplified expression yields: （11）。 5. The method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system as described in claim 4, characterized in that, In step S3, the load resistance R is calculated. L The estimation formula is: （12） In the formula, m∈[0,1] is the weighting factor, μ c This is the compensation coefficient.

6. The method for estimating the equivalent load resistance of a dual-transmitter single-receiver wireless charging system as described in claim 1, characterized in that, The dual-transmitter single-receiver wireless charging system includes two symmetrically arranged LCC resonant networks and one SS resonant network. The two symmetrically arranged LCC resonant networks are the two primary coils of the system, and the SS resonant network is the secondary coil of the system.

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