Power transmission control method and wireless power transmission system

Abstract

The present invention discloses a power transmission control method and a wireless power transmission system, which relate to the field of power transmission control. In this system, a second receiving module is connected in reverse parallel to a first receiving module and is used to connect to a load; a current search interval is determined and a first test duty cycle and a second test duty cycle are determined; the corresponding first ripple intensity and second ripple intensity are determined based on a preset enhanced ripple effective value determination strategy, and the test duty cycle corresponding to the smaller of the two is determined as the endpoint value and the search interval is updated accordingly; when the search termination condition is met, a first target duty cycle is determined according to the current search interval, so that the voltage ripple intensity in the total voltage is within a preset allowable range through the first target duty cycle. In this scheme, under the reverse parallel coupling connection setting, the voltage ripple in the second voltage is adjusted through the first target duty cycle, achieving active filtering and suppression of the voltage ripple intensity in the total voltage, improving the power supply stability to the load, and ensuring the power supply quality.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy transmission control, and in particular to an electric energy transmission control method and a wireless power transmission system. Background Art

[0002] Wireless power transmission overcomes the limitations of traditional wired power supply methods in terms of spatial layout and mechanical connection. For example, magnetically coupled resonant wireless power transmission systems offer high energy transmission efficiency and strong resistance to displacement interference, making them suitable for a variety of wireless power supply scenarios. However, in actual applications, it has been found that these wireless power transmission systems often exhibit significant voltage ripple at the output of the system. This ripple not only reduces the power supply quality to the load, but can also cause electromagnetic interference, reduce system stability, and even affect the normal operation of precision electronic equipment that requires high voltage stability.

[0003] To this end, a passive filtering network is typically deployed to suppress voltage ripple. This passive filtering network primarily utilizes a large-capacity capacitor or a multi-stage inductor-capacitor filtering structure, which then low-pass filters the ripple on the output side of the wireless power transmission system. However, this approach still has certain drawbacks: First, the passive filtering network responds unevenly to ripples of different frequency components, resulting in limited filtering effectiveness, particularly in high-frequency or non-sinusoidal ripple interference scenarios. Second, the passive filtering network relies on a fixed hardware circuit structure and cannot be dynamically adjusted to the state of the wireless power transmission system to achieve ripple filtering, making it unsuitable for practical application.

[0004] Therefore, how to provide a more effective ripple filtering solution is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, the present invention provides an electric energy transmission control method and a wireless power transmission system, which realize active and dynamic filtering and suppression of the voltage ripple intensity in the total voltage after voltage superposition, reduce the ripple amplitude in the total voltage, improve the power supply stability to the load, and ensure the power supply quality.

[0006] To solve the above technical problems, the present invention provides a power transmission control method, which is applied to a control module in a wireless power transmission system, wherein the wireless power transmission system also includes a primary power transmission module and a secondary power reception module, wherein the secondary power reception module includes a first reception module and a second reception module, wherein the output end of the second reception module is connected in reverse parallel to the output end of the first reception module for connection to a load; the control module is connected to a controllable switch in a voltage conversion module in the second reception module; the resonant frequency corresponding to the power transmission of the primary power transmission module is the same as the resonant frequency corresponding to the power reception of the secondary power reception module; the power transmission control method includes:

[0007] S11: In the current control cycle, determining a preset duty cycle interval as a current search interval;

[0008] S12: Determine a first test duty cycle and a second test duty cycle in the current search interval according to a test point selection strategy;

[0009] S13: Determine, based on a preset enhanced ripple effective value determination strategy, a first ripple intensity corresponding to the total voltage output to the load at the first test duty cycle and a second ripple intensity corresponding to the total voltage at the second test duty cycle, so as to determine a test duty cycle corresponding to the smaller of the first ripple intensity and the second ripple intensity as a new endpoint value for duty cycle search;

[0010] S14: determining a new search interval according to the current search interval and the endpoint value, and using the new search interval as the current search interval;

[0011] S15: Determine whether the search termination condition is met; if not, return to S12; if so, determine a first target duty cycle based on the current search interval, so as to adjust the voltage ripple in the second voltage output by the second receiving module through the first target duty cycle, so that the voltage ripple intensity in the total voltage after the first voltage output by the first receiving module and the second voltage are superimposed is within a preset allowable range.

[0012] Furthermore, step S12 includes:

[0013] Determine a first test duty cycle according to the current search interval and a first preset relationship;

[0014] The first preset relationship is:

[0015] ;

[0016] in, For the first test duty cycle, Indicates the right endpoint of the current search interval, Indicates the left endpoint of the current search interval, is the first preset parameter and 0< <1;

[0017] Determine a second test duty cycle according to the current search interval and a second preset relationship;

[0018] The second preset relationship is:

[0019] ;

[0020] in, represents the second test duty cycle.

[0021] Furthermore, based on a preset enhanced ripple effective value determination strategy, determining a first ripple intensity corresponding to the total voltage output to the load under the first test duty cycle includes:

[0022] determining a first PWM signal corresponding to the first test duty cycle, and controlling the controllable switch based on the first PWM signal;

[0023] Obtaining N consecutive sampled voltages of the total voltage output to the load at a preset sampling frequency to obtain a voltage sample sequence, where N is an integer greater than 1;

[0024] Performing sliding filtering on the voltage sample sequence to obtain a smoothed voltage sequence;

[0025] determining an average DC component corresponding to the smoothed voltage sequence;

[0026] Determine a difference between a smoothed voltage corresponding to an i-th voltage sampling point in a smoothed voltage sequence and the average DC component as a ripple deviation corresponding to the i-th voltage sampling point, where 1≤i≤N and i is an integer;

[0027] The first ripple intensity corresponding to the total voltage output to the load under the first test duty cycle is determined according to a third preset relationship and the ripple deviation; the third preset relationship is:

[0028] ;

[0029] in, is the ripple deviation corresponding to the i-th voltage sampling point, represents the first ripple intensity.

[0030] Furthermore, after determining the first target duty cycle according to the current search interval, the method further includes:

[0031] determining an adjusted basic duty cycle based on the first target duty cycle and its corresponding search interval, wherein the ripple intensity corresponding to the total voltage at the adjusted basic duty cycle is less than the ripple intensity corresponding to the total voltage at the first target duty cycle;

[0032] The duty cycle is fine-tuned according to the preset fine search strategy and the adjusted basic duty cycle until a preset adjustment termination condition is reached, and the duty cycle at this time is determined to be the second target duty cycle.

[0033] Furthermore, determining and adjusting the basic duty cycle based on the first target duty cycle and its corresponding search interval includes:

[0034] S21: determining a dynamic step size update interval based on a search interval corresponding to the first target duty cycle, so as to determine a first adjustment step size according to the dynamic step size update interval;

[0035] S22: Determine that a difference between the first target duty cycle and the first adjustment step is a first candidate duty cycle, and a sum of the first target duty cycle and the first adjustment step is a second candidate duty cycle;

[0036] S23: Determine, based on the preset enhanced ripple effective value determination strategy, a third ripple intensity corresponding to the total voltage under the first candidate duty cycle and a fourth ripple intensity corresponding to the total voltage under the second candidate duty cycle;

[0037] S24: Determine the smaller of the third ripple intensity and the fourth ripple intensity;

[0038] S25: Determine whether the smaller one is smaller than the ripple intensity corresponding to the total voltage under the first target duty cycle; if so, proceed to S26; if not, proceed to S27;

[0039] S26: Determine the candidate duty cycle corresponding to the smaller one as the basic duty cycle for adjustment;

[0040] S27: re-determine a second adjustment step size according to the dynamic step size update interval, where the second adjustment step size is smaller than the first adjustment step size; use the second adjustment step size as a new first adjustment step size and return to S22.

[0041] Further, the duty cycle is fine-tuned according to the preset fine search strategy and the adjusted basic duty cycle until a preset adjustment termination condition is reached, and the duty cycle at this time is determined to be the second target duty cycle, including:

[0042] According to the first step length iterative relationship for determining the iterative step length in the j+1th search, the search is gradually conducted in the first direction starting from the regulated basic duty cycle until the fifth ripple intensity corresponding to the regulated basic duty cycle in the j+1th search is greater than the fifth ripple intensity corresponding to the regulated basic duty cycle in the jth search, and the regulated basic duty cycle in the jth search is determined to be a candidate duty cycle; wherein the first direction is the direction in which the first target duty cycle points to the regulated basic duty cycle, and the first step length iterative relationship is:

[0043] ;

[0044] represents the iterative step size for the j+1th search, represents the iterative step size under the j-th search, is the second preset parameter and , and is the third preset parameter, represents the right endpoint of the search interval corresponding to the first target duty cycle, represents the left endpoint of the search interval corresponding to the first target duty cycle;

[0045] According to a second step length iterative relationship for determining an iterative step length in the s+1th search, a search is performed starting from the candidate duty cycle and stepping in a second direction until a preset adjustment termination condition is reached, whereupon the duty cycle at that time is determined to be a second target duty cycle; wherein the second direction is opposite to the first direction; and the second step length iterative relationship is:

[0046] ;

[0047] Indicates the iterative step size for the s+1th search, represents the iterative step size under the s-th search, is the fourth preset parameter and , and This is the fifth preset parameter.

[0048] To solve the above technical problems, the present invention further provides a wireless power transmission system, comprising a primary power transmitting module, a secondary power receiving module, and a control module; the secondary power receiving module comprises a first receiving module and a second receiving module, the output end of the second receiving module being connected in reverse parallel to the output end of the first receiving module for connection to a load; the control module is connected to a controllable switch in a voltage conversion module in the second receiving module; the resonant frequency corresponding to power transmission by the primary power transmitting module is the same as the resonant frequency corresponding to power reception by the secondary power receiving module;

[0049] The control module is used to execute the steps of the power transmission control method as described above.

[0050] Furthermore, the primary power transmission module includes an inverter module, a first inductor, a first capacitor, a second capacitor, and a transmitting coil; the inverter module includes a first bridge arm and a second bridge arm arranged in parallel, and the first end of the first circuit formed by the parallel connection is connected to the positive output terminal of the power supply, and the second end of the first circuit is connected to the negative output terminal of the power supply;

[0051] The first end of the transmitting coil is connected to one end of the first capacitor, and the second end is connected to one end of the second capacitor and the midpoint of the second bridge arm;

[0052] One end of the first inductor is connected to the other end of the first capacitor and the other end of the second capacitor respectively, and the other end of the first inductor is connected to the midpoint of the first bridge arm.

[0053] Furthermore, the first receiving module includes a first receiving coil, a third capacitor, and a first rectifier module; the first rectifier module includes a third bridge arm and a fourth bridge arm arranged in parallel, and the first end of the second circuit formed by the parallel connection is connected to the second output end of the second receiving module, and the second end of the second circuit is connected to the first output end of the second receiving module;

[0054] The first end of the first receiving coil is connected to one end of the third capacitor, and the second end is connected to the midpoint of the third bridge arm;

[0055] The other end of the third capacitor is connected to the midpoint of the fourth bridge arm.

[0056] Furthermore, the second receiving module includes a second receiving coil, a fourth capacitor, a fifth capacitor, a second inductor, a second rectifier module and a voltage conversion module; the second rectifier module includes a fifth bridge arm and a sixth bridge arm arranged in parallel, a first end of a third circuit formed by the parallel connection is connected to the first end of the voltage conversion module, and the common end of the connections serves as the first output end of the second receiving module, and a second end of the third circuit is connected to the second end of the voltage conversion module, and the common end of the connections serves as the second output end of the second receiving module;

[0057] The control end of the controllable switch in the voltage conversion module is connected to the control module;

[0058] A first end of the second receiving coil is connected to one end of the fourth capacitor, a second end is connected to one end of the fifth capacitor, and a common end of the connections is connected to the midpoint of the fifth bridge arm;

[0059] One end of the second inductor is connected to the other end of the fourth capacitor and the other end of the fifth capacitor respectively, and the other end of the second inductor is connected to the midpoint of the sixth bridge arm.

[0060] The beneficial effects of this application are:

[0061] The present application provides an electric energy transmission control method and a wireless power transmission system, wherein the secondary side electric energy receiving module in the wireless power transmission system includes a first receiving module and a second receiving module, the output end of the second receiving module is reversely connected in parallel with the output end of the first receiving module for connection to a load, and the control module is connected to a controllable switch in a voltage conversion module in the second receiving module. Then, under the current control cycle, a preset duty cycle interval is determined as the current search interval; the first test duty cycle and the second test duty cycle in the current search interval are determined according to the test point selection strategy; and the total voltage output to the load under the first test duty cycle is determined based on the preset enhanced ripple effective value determination strategy. The first ripple intensity corresponding to the first ripple intensity and the second ripple intensity corresponding to the total voltage under the second test duty cycle are used to determine the test duty cycle corresponding to the smaller of the first ripple intensity and the second ripple intensity as the new endpoint value for the duty cycle search; a new search interval is determined based on the current search interval and the endpoint value, and the new search interval is used as the current search interval; when it is determined that the search termination condition has been met, a first target duty cycle is determined based on the current search interval, so as to adjust the voltage ripple in the second voltage output by the second receiving module using the first target duty cycle, so that the voltage ripple intensity in the total voltage after the superposition of the first voltage and the second voltage output by the first receiving module is within a preset allowable range. It can be seen that this solution is not limited by the frequency of the voltage ripple. Under the reverse parallel coupling connection setting between the first receiving module and the second receiving module, the voltage ripple in the second voltage is adjusted by the first target duty cycle, achieving active and dynamic filtering and suppression of the voltage ripple intensity in the total voltage after the voltage superposition, reducing the ripple amplitude in the total voltage, improving the power supply stability to the load, ensuring the power supply quality, and facilitating practical application.

[0062] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0064] Figure 1 A flow chart of a power transmission control method provided by the present invention;

[0065] Figure 2 A schematic structural diagram of a wireless power transmission system provided by the present invention;

[0066] Figure 3 A schematic structural diagram of a Buck-Boost DC-DC conversion circuit provided by the present invention;

[0067] Figure 4 This is a schematic diagram of the first voltage, the second voltage and the total voltage changing with time provided by the present invention. DETAILED DESCRIPTION

[0068] The core of the present invention is to provide an electric energy transmission control method and a wireless power transmission system to achieve active and dynamic filtering and suppression of the voltage ripple intensity in the total voltage after voltage superposition, reduce the ripple amplitude in the total voltage, improve the power supply stability to the load, and ensure the power supply quality.

[0069] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0070] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0071] Please refer to Figure 1 and Figure 2 , Figure 1 A flow chart of a power transmission control method provided by the present invention; Figure 2 This is a structural diagram of a wireless power transmission system provided by the present invention.

[0072] The power transmission control method is applied to a control module 1 in a wireless power transmission system. The wireless power transmission system also includes a primary power transmission module 2 and a secondary power receiving module. The secondary power receiving module includes a first receiving module 31 and a second receiving module 32. The output end of the second receiving module 32 is connected in reverse parallel with the output end of the first receiving module 31 and is used to connect to the load R L connection; the control module 1 is connected to the controllable switch in the voltage conversion module 322 in the second receiving module 32; the resonant frequency corresponding to the primary side power transmission module 2 when transmitting power is the same as the resonant frequency corresponding to the secondary side power receiving module when receiving power; the power transmission control method includes:

[0073] S11: In the current control cycle, determining a preset duty cycle interval as a current search interval;

[0074] S12: Determine a first test duty cycle and a second test duty cycle in the current search interval according to a test point selection strategy;

[0075] S13: Determine the output to the load R under the first test duty cycle based on the preset enhanced ripple effective value determination strategy L a first ripple intensity corresponding to the total voltage of the first ripple and a second ripple intensity corresponding to the total voltage under the second test duty cycle, so as to determine the test duty cycle corresponding to the smaller one of the first ripple intensity and the second ripple intensity as a new endpoint value for duty cycle search;

[0076] S14: Determine a new search interval based on the current search interval and endpoint values, and use the new search interval as the current search interval;

[0077] S15: Determine whether the search termination condition is met; if not, return to S12; if so, enter S16;

[0078] S16: Determine a first target duty cycle based on the current search interval, so as to adjust the voltage ripple in the second voltage output by the second receiving module 32 through the first target duty cycle, so that the voltage ripple intensity in the total voltage after the first voltage output by the first receiving module 31 and the second voltage are superimposed is within a preset allowable range.

[0079] In this embodiment, the primary power transmission module 2 in the wireless power transmission system is used for wireless power transmission, and the secondary power receiving module is used for wireless power reception, and the corresponding resonant frequency during the wireless power transmission is the same as the corresponding resonant frequency during the power reception by the secondary power receiving module, so as to ensure the smooth generation of resonance and the correct superposition of the subsequent first voltage and the second voltage. Specifically, the reverse parallel connection described in this application means that the first output terminal of the second receiving module 32 is connected to the second output terminal of the first receiving module 31, and the second output terminal of the second receiving module 32 is connected to the first output terminal of the first receiving module 31, such as Figure 2 As shown; the load R L It can be any electrical load and is not particularly limited here.

[0080] Specifically, the preset duty cycle interval in step S11 is essentially based on the load R L An initial duty cycle search interval is determined according to the power supply requirements and covers the area where the minimum voltage ripple amplitude corresponding to the expected total voltage is located; in step S13, the first ripple intensity corresponding to the first test duty cycle is determined based on the preset enhanced ripple effective value determination strategy, and the second ripple intensity corresponding to the second test duty cycle is determined based on the preset enhanced ripple effective value determination strategy. When the first ripple intensity is less than the second ripple intensity, the first test duty cycle is the new endpoint value for the duty cycle search, and when the second ripple intensity is less than the first ripple intensity, the second test duty cycle is the new endpoint value for the duty cycle search.

[0081] The search termination condition in step S15 can be set as the length of the current search interval being less than a preset threshold. The step of determining the first target duty cycle based on the current search interval in step S16 can be as follows: determining the average of the difference between the right endpoint and the left endpoint of the current search interval as the first target duty cycle. Based on the first target duty cycle, a corresponding PWM (Pulse Width Modulation) signal can be generated and sent to the control terminal of the controllable switch to control the on and off of the controllable switch, thereby regulating the voltage ripple in the second voltage output by the second receiving module 32 so that the voltage ripple intensity of the total voltage, which is the sum of the first voltage and the second voltage output by the first receiving module 31, is within a preset allowable range. In other words, the voltage ripple in the first voltage and the voltage ripple in the second voltage are offset by the sum of the two voltages, minimizing the ripple amplitude of the total voltage.

[0082] It should also be noted that the voltage conversion module 322 here includes but is not limited to a DC-DC converter module (Direct Current-Direct Current, DC-DC), and more specifically can be a Buck-Boost type DC-DC conversion circuit. The corresponding circuit structure is described in the following embodiment and will not be repeated here.

[0083] In summary, the present application provides a method for controlling electric energy transmission, which is not limited by the frequency of the voltage ripple. Under the reverse parallel coupling connection between the first receiving module 31 and the second receiving module 32, the voltage ripple in the second voltage is adjusted to achieve active and dynamic filtering and suppression of the voltage ripple intensity in the total voltage after voltage superposition, reduce the ripple amplitude in the total voltage, keep the voltage ripple in the total voltage at a minimum state, have good dynamic adaptability and robustness, and achieve adaptive closed-loop regulation of ripple control; and this active and dynamic filtering and suppression scheme enables the wireless power transmission system to eliminate the dependence on large-capacity filter capacitors or complex passive filtering networks, and is more adaptable to the current development trend of lightweight, miniaturization, and high power density of wireless power transmission systems; it is beneficial to suppress electromagnetic interference, improve the overall electromagnetic compatibility and operational stability of the wireless power transmission system, improve the power supply stability to the load, ensure the power supply quality, and facilitate practical applications.

[0084] Based on the above embodiment:

[0085] In some embodiments, step S12 includes:

[0086] Determine a first test duty cycle according to the current search interval and a first preset relationship;

[0087] The first preset relationship is:

[0088] ;

[0089] in, For the first test duty cycle, Indicates the right endpoint of the current search interval, Indicates the left endpoint of the current search interval, is the first preset parameter and 0< <1;

[0090] Determine a second test duty cycle according to the current search interval and a second preset relationship;

[0091] The second preset relationship is:

[0092] ;

[0093] in, Indicates the second test duty cycle.

[0094] Specifically, the current search interval is [ , ], as a preferred setting, when the search termination condition is that the length of the current search interval is less than a preset threshold, The value may be 0.618, which can make the search speed for the first target duty cycle the fastest.

[0095] It should also be noted that in step S14, a new search interval is determined based on the current search interval and the endpoint value, including: when the first test duty cycle is the new endpoint value for duty cycle search, determining the left endpoint is and the right endpoint is the search interval of the first test duty cycle as the new search interval; when the second test duty cycle is the new endpoint value for duty cycle search, determine that the left endpoint is the second test duty cycle and the right endpoint is The search interval is the new search interval.

[0096] In some embodiments, based on a preset enhanced ripple effective value determination strategy, the output to the load R under the first test duty cycle is determined. L The total voltage corresponding to the first ripple intensity includes:

[0097] Determining a first PWM signal corresponding to a first test duty cycle, and controlling the controllable switch based on the first PWM signal;

[0098] Get the output to load R L The total voltage of , N consecutive sampled voltages collected at a preset sampling frequency to obtain a voltage sample sequence, where N is an integer greater than 1;

[0099] Perform sliding filtering on the voltage sample sequence to obtain a smooth voltage sequence;

[0100] Determine the average DC component corresponding to the smoothed voltage sequence;

[0101] Determine the difference between the smoothed voltage corresponding to the i-th voltage sampling point in the smoothed voltage sequence and the average DC component as the ripple deviation corresponding to the i-th voltage sampling point, where 1≤i≤N and i is an integer;

[0102] According to the third preset relationship and the ripple deviation, the output to the load R under the first test duty cycle is determined. L The first ripple intensity corresponding to the total voltage; the third preset relationship is:

[0103] ;

[0104] in, is the ripple deviation corresponding to the i-th voltage sampling point, Indicates the first ripple intensity.

[0105] In this embodiment, the on and off of the controllable switch can be controlled based on the first PWM signal, thereby obtaining the output to the load R L The total voltage of N consecutive sampled voltages collected at a preset sampling frequency, specifically, Figure 2 As shown, the control module 1 here may include a voltage sampling circuit, a microprocessor and a switch tube driving circuit connected in sequence, based on the load R L The voltage across the two ends is the total voltage. The voltage sampling circuit is also connected to the load R L Connection for collecting load R L The voltage at both ends is sent to the microprocessor; the microprocessor is used to obtain the load R converted into a digital signal through ADC sampling (Analog to Digital Converter, analog to digital conversion) L The voltage at both ends is sensed, and the above steps are executed accordingly to output different duty cycles; the switch tube driving circuit is also connected to the control end of the controllable switch, and is used to generate a corresponding PWM signal according to the received duty cycle; it can be understood that the voltage sampling circuit, microprocessor and switch tube driving circuit here can be powered by an auxiliary power supply; the microprocessor can also support interrupt scheduling, etc., which is not particularly limited here.

[0106] The preset sampling frequency here can preferably be set to no less than 10 times the above-mentioned resonant frequency. The reason for this setting is that, according to the Nyquist sampling theorem, in order to accurately reconstruct the signal and more accurately capture the details of the ripple signal in the total voltage (such as peak value, phase, etc.), avoid spectrum aliasing, and improve the accuracy of subsequent filtering and ripple intensity calculation, the preset sampling frequency is set ≥ (10 times the above-mentioned resonant frequency) to achieve high-frequency sampling, capture more signal details, and avoid mistaking the ripple in the total voltage for noise and filtering it out due to the sampling frequency being too low, resulting in distortion of the ripple intensity determination result. In addition, this high-frequency sampling is conducive to real-time tracking of changes in the ripple signal, ensuring the accuracy and reliability of the ripple intensity determination result.

[0107] It should also be noted that the voltage sample sequence is subjected to sliding filtering to eliminate sudden noise interference and obtain a smoothed voltage sequence; the step of determining the average DC component corresponding to the smoothed voltage sequence may be: determining the sum of the smoothed voltages corresponding to each voltage sampling point under the smoothed voltage sequence, and determining the result of dividing the sum by N as the average DC component.

[0108] It can be seen that the above settings are conducive to reliably determining the ripple intensity corresponding to the total voltage under different duty cycles, thereby guiding the convergence direction of the power transmission control method and improving the stability and accuracy of the ripple intensity determination results in the presence of sampling noise and transient disturbances.

[0109] In some embodiments, after determining the first target duty cycle according to the current search interval, the method further includes:

[0110] Determining an adjustment base duty cycle based on the first target duty cycle and its corresponding search interval, wherein the ripple intensity corresponding to the total voltage at the adjustment base duty cycle is smaller than the ripple intensity corresponding to the total voltage at the first target duty cycle;

[0111] According to the preset fine search strategy, the basic duty cycle is adjusted to perform duty cycle fine-tuning until a preset adjustment termination condition is reached, and the duty cycle at this time is determined to be the second target duty cycle.

[0112] Specifically, considering that in actual applications where the control accuracy requirements are not very high, it is sufficient to rely on the first target duty cycle to achieve voltage ripple suppression. However, for certain situations where the control accuracy requirements are very high, the above method can be used to conduct further search based on the first target duty cycle to determine the second target duty cycle, and then through this two-stage search method, it is ensured that the voltage ripple suppression effect meets the expected requirements.

[0113] In some embodiments, determining and adjusting the base duty cycle based on the first target duty cycle and its corresponding search interval includes:

[0114] S21: determining a dynamic step length update interval based on a search interval corresponding to the first target duty cycle, so as to determine a first adjustment step length according to the dynamic step length update interval;

[0115] S22: Determine that the difference between the first target duty cycle and the first adjustment step is a first candidate duty cycle, and the sum of the first target duty cycle and the first adjustment step is a second candidate duty cycle;

[0116] S23: Determine a third ripple intensity corresponding to the total voltage under the first candidate duty cycle and a fourth ripple intensity corresponding to the total voltage under the second candidate duty cycle based on a preset enhanced ripple effective value determination strategy;

[0117] S24: determining the smaller of the third ripple intensity and the fourth ripple intensity;

[0118] S25: Determine whether the smaller one is smaller than the ripple intensity corresponding to the total voltage under the first target duty cycle; if so, proceed to S26; if not, proceed to S27;

[0119] S26: Determine the candidate duty cycle corresponding to the smaller one as the basic duty cycle for adjustment;

[0120] S27: re-determine a second adjustment step size according to the dynamic step size update interval, where the second adjustment step size is smaller than the first adjustment step size; use the second adjustment step size as the new first adjustment step size and return to S22.

[0121] Specifically, step S21 may include: determining the difference between the right endpoint and the left endpoint of the search interval corresponding to the first target duty cycle, and determining the dynamic step size update interval as [ , ],in, is the sixth preset parameter, is the seventh preset parameter and , is the difference; and any value within the dynamic step size update interval is determined as the first adjustment step size. It can be seen that the above setting can ensure rapid local exploration without losing control and going out of bounds. It should be noted that, preferably, the sixth preset parameter can be 0.1, and the seventh preset parameter can be 0.2.

[0122] When the smaller one is not less than the ripple intensity corresponding to the total voltage under the first target duty cycle, it means that no ripple improvement is brought about in the downward direction and the upward direction (the downward direction is the direction in which the first target duty cycle points to the first candidate duty cycle, and the upward direction is the direction in which the first target duty cycle points to the second candidate duty cycle), which means that the first adjustment step currently being searched is too large, so step S27 is entered to select a second adjustment step that is smaller than the current first adjustment step within the dynamic step update interval, and the search is continued until the basic adjustment duty cycle is found.

[0123] In some embodiments, when the base duty cycle is adjusted according to a preset fine search strategy and the duty cycle is fine-tuned until a preset adjustment termination condition is reached, determining the duty cycle at this time as the second target duty cycle includes:

[0124] S31: According to the first step length iterative relationship for determining the iterative step length in the j+1th search, gradually search from the adjustment base duty cycle in the first direction until the fifth ripple intensity corresponding to the adjustment base duty cycle in the j+1th search is greater than the fifth ripple intensity corresponding to the adjustment base duty cycle in the jth search, determining that the adjustment base duty cycle in the jth search is a candidate duty cycle; wherein the first direction is the direction in which the first target duty cycle points to the adjustment base duty cycle, and the first step length iterative relationship is:

[0125] ;

[0126] represents the iterative step size for the j+1th search, represents the iterative step size under the j-th search, is the second preset parameter and , and is the third preset parameter, represents the right endpoint of the search interval corresponding to the first target duty cycle, represents the left endpoint of the search interval corresponding to the first target duty cycle;

[0127] According to the second step length iteration relationship for determining the iteration step length in the s+1th search, the search is gradually conducted from the candidate duty cycle in the second direction until the preset adjustment termination condition is reached, and the duty cycle at this time is determined to be the second target duty cycle; wherein the second direction is opposite to the first direction; the second step length iteration relationship is:

[0128] ;

[0129] Indicates the iterative step size for the s+1th search, represents the iterative step size under the s-th search, is the fourth preset parameter and , and This is the fifth preset parameter.

[0130] In this embodiment, in order to accurately obtain the second target duty cycle, a fine search is performed using the variable step size search method. Specifically, step S31 may include:

[0131] S41: let j = 1;

[0132] S42: Determine that the adjustment basic duty cycle is the current duty cycle, and the first adjustment step corresponding to the adjustment basic duty cycle is the iterative step in the j-th search;

[0133] S43: Determine the iterative step length for the j+1th search according to the first step length iteration relation and the iterative step length for the jth search;

[0134] S44: Determine the duty cycle under the j+1th search as the result of a first operation performed on the current duty cycle and the iterative step size under the j+1th search; the first operation is performed when the adjustment base duty cycle is [ , the first target duty cycle] is a subtraction operation, and the first operation is performed when the adjustment basic duty cycle is in the range of [the first target duty cycle, ]When it is within this range, it is an addition operation;

[0135] S45: Determine, based on the preset enhanced ripple effective value determination strategy, a fifth ripple intensity corresponding to the total voltage at the duty cycle in the j+1th search;

[0136] S46: Determine whether the fifth ripple intensity corresponding to the total voltage at the duty cycle under the j+1th search is smaller than the fifth ripple intensity corresponding to the total voltage at the current duty cycle; if so, proceed to S47; if not, proceed to S48;

[0137] S47: Determine the duty cycle under the j+1th search as the new current duty cycle, set j=j+1 and return to S43;

[0138] S48: Determine the current duty cycle as a candidate duty cycle.

[0139] It should be noted that, preferably, You can take 1.1, It can be taken as 0.2; when it is determined that the fifth ripple intensity corresponding to the duty cycle under the j+1th search is not less than the fifth ripple intensity corresponding to the current duty cycle, it means that the j+1th search can no longer bring about improvement in ripple suppression, so step S48 is entered.

[0140] Furthermore, taking the preset adjustment termination condition as the ripple improvement amplitude being less than the preset slight improvement threshold for T consecutive times as an example (T is an integer not less than 1, and preferably T can be set to 5), step S32 may include:

[0141] S51: Let s=1;

[0142] S52: Determine that the candidate duty cycle is the current duty cycle, and the iteration step corresponding to the current duty cycle is the iteration step in the s-th search;

[0143] S53: Determine the iterative step length for the s+1th search according to the second step length iteration relation and the iterative step length for the sth search;

[0144] S54: Determine the duty cycle in the s+1th search as a result of a second operation performed on the current duty cycle and the iteration step size in the s+1th search; the second operation is an addition operation when the first operation is a subtraction operation, and is a subtraction operation when the first operation is an addition operation;

[0145] S55: Determine, based on the preset enhanced ripple effective value determination strategy, a sixth ripple intensity corresponding to the total voltage at the duty cycle in the (s+1)th search;

[0146] S56: Determine whether the sixth ripple intensity corresponding to the total voltage at the duty cycle under the s+1th search is less than the sixth ripple intensity corresponding to the total voltage at the current duty cycle; if so, proceed to S57; if not, proceed to S59;

[0147] S57: Determine whether the difference is less than a preset slight improvement threshold; if so, proceed to S58; if not, proceed to S60;

[0148] S58: Determine whether the event that the difference is less than the preset slight improvement threshold has occurred T times; if so, determine that the duty cycle under the s+1th search is the second target duty cycle; if not, proceed to S60;

[0149] S59: Keep the current duty cycle unchanged, set s=s+1 and return to S53;

[0150] S60: Determine the duty cycle under the s+1th search as the new current duty cycle, set s=s+1 and return to S53.

[0151] It is understandable that the preset adjustment termination condition can also be that the iteration step size at the s+1th moment determined by the second step size iteration relationship is not greater than , then step S32 can be set in the same manner as above, which will not be described in detail here. It should also be noted that, preferably, can be 0.9 and It can be 0.01.

[0152] The present invention also provides a wireless power transmission system, including a primary power transmitting module 2, a secondary power receiving module and a control module 1; the secondary power receiving module includes a first receiving module 31 and a second receiving module 32, the output end of the second receiving module 32 is connected in reverse parallel with the output end of the first receiving module 31 and is used to connect to the load R L connection; the control module 1 is connected to the controllable switch in the voltage conversion module 322 of the second receiving module 32; the resonant frequency corresponding to the primary power transmitting module 2 when transmitting power is the same as the resonant frequency corresponding to the secondary power receiving module when receiving power;

[0153] The control module 1 is used to execute the steps of the power transmission control method as described above.

[0154] For an introduction to the wireless power transmission system provided in this application, please refer to the embodiment of the power transmission control method described above, and no further details will be given here. It is understood that the switch tube drive circuit in the control module 1 is specifically connected to the voltage conversion module 322 in the second receiving module 32 (more specifically, to the control terminal of the controllable switch in the voltage conversion module 322).

[0155] In some embodiments, the primary power transmission module 2 includes an inverter module 21, a first inductor Lp, a first capacitor C1, a second capacitor Cp1, and a transmitting coil L1. The inverter module 21 includes a first bridge arm and a second bridge arm connected in parallel. The first end of the first circuit formed by the parallel connection is connected to the positive output terminal of the power supply Vin, and the second end of the first circuit is connected to the negative output terminal of the power supply Vin.

[0156] The first end of the transmitting coil L1 is connected to one end of the first capacitor C1, and the second end is connected to one end of the second capacitor Cp1 and the midpoint of the second bridge arm;

[0157] One end of the first inductor Lp is connected to the other end of the first capacitor C1 and the other end of the second capacitor Cp1 respectively, and the other end is connected to the midpoint of the first bridge arm.

[0158] In this embodiment, the inverter module 21 here can be a full-bridge high-frequency inverter circuit, which is used to invert the direct current output by the power supply Vin into alternating current with a preset specific frequency, specifically, Figure 2 As shown, the inverter module 21 includes a first bridge arm formed by a first power field effect transistor Q1 and a second power field effect transistor Q2 connected in series, and a second bridge arm formed by a third power field effect transistor Q3 and a fourth power field effect transistor Q4 connected in series. The midpoint of the first bridge arm refers to the common terminal connected to the first power field effect transistor Q1 and the second power field effect transistor Q2, and the midpoint of the second bridge arm refers to the common terminal connected to the third power field effect transistor Q3 and the fourth power field effect transistor Q4. The common terminal connected to the drain of the first power field effect transistor Q1 and the drain of the third power field effect transistor Q3 serves as the first terminal of the first circuit, and the source of the second power field effect transistor Q2 and the source of the fourth power field effect transistor Q4 serve as the second terminal of the first circuit. It can be understood that the control terminals of the first power field effect transistor Q1, the second power field effect transistor Q2, the third power field effect transistor Q3, and the fourth power field effect transistor Q4 are connected to a controller for controlling inversion to ensure that the full-bridge high-frequency inverter circuit reliably implements the inversion function. Figure 2 Due to the limitation of showing the key points in the picture and avoiding confusion in the connection, the illustration of the controller is omitted for the time being.

[0159] The first inductor Lp, first capacitor C1, second capacitor Cp1, and transmitting coil L1 form a first magnetically coupled resonant circuit (using an LCC resonant network). Combined with the output of inverter module 21, this circuit achieves resonance in the primary circuit, efficiently transferring energy from the primary to the secondary. The closed loop formed by the first inductor Lp and second capacitor Cp1 is the first resonant cavity, while the closed loop formed by the first capacitor C1, second capacitor Cp1, and transmitting coil L1 is the second resonant cavity. The first and second resonant cavities operate at the same resonant frequency.

[0160] In some embodiments, the first receiving module 31 includes a first receiving coil L2, a third capacitor C2, and a first rectifier module 311; the first rectifier module 311 includes a third bridge arm and a fourth bridge arm arranged in parallel, and the first end of the second circuit formed by the parallel connection is connected to the second output end of the second receiving module 32, and the second end of the second circuit is connected to the first output end of the second receiving module 32;

[0161] A first end of the first receiving coil L2 is connected to one end of the third capacitor C2, and a second end is connected to the midpoint of the third bridge arm;

[0162] The other end of the third capacitor C2 is connected to the midpoint of the fourth bridge arm.

[0163] In this embodiment, the first rectifier module 311 here can be a full-bridge high-frequency rectifier circuit, specifically, as Figure 2 As shown, the first rectifier module 311 includes a third bridge arm formed by a first rectifier diode D1 and a third rectifier diode D3 connected in series, and a fourth bridge arm formed by a second rectifier diode D2 and a fourth rectifier diode D4 connected in series. The midpoint of the third bridge arm refers to the common end connected to the first rectifier diode D1 and the third rectifier diode D3, and the midpoint of the fourth bridge arm refers to the common end connected to the second rectifier diode D2 and the fourth rectifier diode D4. The common end where the cathode of the first rectifier diode D1 and the cathode of the second rectifier diode D2 are connected serves as the first end of the second circuit, and the common end where the anode of the third rectifier diode D3 and the anode of the fourth rectifier diode D4 are connected serves as the second end of the second circuit.

[0164] The first receiving coil L2 and the third capacitor C2 form a second magnetically coupled resonant circuit (using an S-series resonant network). The closed loop formed by the first receiving coil L2 and the third capacitor C2 is a third resonant cavity. The first resonant cavity, the second resonant cavity, and the third resonant cavity all have the same corresponding resonant frequency during operation.

[0165] In some embodiments, the second receiving module 32 includes a second receiving coil L3, a fourth capacitor C3, a fifth capacitor Cs, a second inductor Ls, a second rectifier module 321, and a voltage conversion module 322; the second rectifier module 321 includes a fifth bridge arm and a sixth bridge arm arranged in parallel, and a first end of a third circuit formed by the parallel connection is connected to a first end of the voltage conversion module 322, and the common end of the connection serves as a first output end of the second receiving module 32; a second end of the third circuit is connected to a second end of the voltage conversion module 322, and the common end of the connection serves as a second output end of the second receiving module 32;

[0166] The control end of the controllable switch in the voltage conversion module 322 is connected to the control module 1;

[0167] A first end of the second receiving coil L3 is connected to one end of the fourth capacitor C3, a second end is connected to one end of the fifth capacitor Cs, and a common end of the connections is connected to the midpoint of the fifth bridge arm;

[0168] One end of the second inductor Ls is connected to the other end of the fourth capacitor C3 and the other end of the fifth capacitor Cs respectively, and the other end is connected to the midpoint of the sixth bridge arm.

[0169] In this embodiment, the second rectifier module 321 here can be a full-bridge high-frequency rectifier circuit, specifically, as Figure 2 As shown, the second rectifier module 321 includes a fifth bridge arm formed by a fifth rectifier diode D5 and a seventh rectifier diode D7 connected in series, and a sixth bridge arm formed by a sixth rectifier diode D6 and an eighth rectifier diode D8 connected in series. The midpoint of the fifth bridge arm refers to the common end connected to the fifth rectifier diode D5 and the seventh rectifier diode D7, and the midpoint of the sixth bridge arm refers to the common end connected to the sixth rectifier diode D6 and the eighth rectifier diode D8. The common end where the cathode of the fifth rectifier diode D5 and the cathode of the sixth rectifier diode D6 are connected serves as the first end of the third circuit, and the common end where the anode of the seventh rectifier diode D7 and the anode of the eighth rectifier diode D8 are connected serves as the second end of the third circuit.

[0170] The second receiving coil L3, the fourth capacitor C3, the fifth capacitor Cs, and the second inductor Ls form a third magnetically coupled resonant circuit (using an LCC resonant network). The closed loop formed by the second receiving coil L3, the fourth capacitor C3, and the fifth capacitor Cs is a fourth resonant cavity. The closed loop formed by the fifth capacitor Cs and the second inductor Ls is a fifth resonant cavity. The first, second, third, fourth, and fifth resonant cavities all have the same corresponding resonant frequencies during operation.

[0171] It can be understood that through the structural setting in the above embodiment, the second receiving module 32 can achieve efficient wireless energy reception and rectification output, while ensuring that the output second voltage has a clear phase characteristic, so as to facilitate superposition with the first voltage output by the first receiving module 31, thereby achieving voltage ripple suppression of the total voltage.

[0172] It should also be noted that the voltage conversion module 322 includes but is not limited to a DC-DC converter module, and more specifically can be a Buck-Boost type DC-DC conversion circuit, please refer to Figure 3 , Figure 3 This is a schematic diagram of the structure of a Buck-Boost DC-DC conversion circuit provided by the present invention. Figure 3 Due to the limitation of the picture display focus and to avoid confusion of the connection lines, the control module 1 is illustrated in the form of a circle plus a reference mark; Figure 3As shown, the Buck-Boost DC-DC conversion circuit includes a controllable switch S1, a freewheeling diode D9, an energy storage inductor L4 and an output capacitor C4. The control end of the controllable switch S1 is connected to the control module 1, and the first end of the controllable switch S1 is used to be connected to the first end of the third circuit. One end of the energy storage inductor L4 is connected to the second end of the controllable switch S1 and the cathode of the freewheeling diode D9. The other end of the energy storage inductor L4 is connected to one end of the output capacitor C4, and the connected end is led out for connection to the second end of the third circuit, and the other end is led out for connection to the first end of the third circuit. The other end of the output capacitor C4 is connected to the anode of the freewheeling diode D9, and the common end of the connection is used to be connected to the second end of the third circuit. For the sake of clarity, Figure 3 The terminal connected to the first end of the third circuit is marked with a +, and the terminal connected to the second end of the third circuit is marked with a -. Furthermore, the controllable switch S1 herein can be any switching transistor, such as a field-effect transistor, a bipolar transistor, or other semiconductor device suitable for switching operation, and is not particularly limited herein.

[0173] Based on the above embodiments, it can be seen that the solution provided by the present application does not require the introduction of large-capacity filter capacitors or complex passive filter networks, which is conducive to the lightweight and miniaturized integrated design of the system, and is conducive to further integration with other systems or platforms. It has good portability and flexible adaptability, and is combined with an active ripple suppression solution on the basis of the above wireless power transmission system, which can effectively suppress the output to the load R on the basis of ensuring compact structure and high efficiency. L The voltage ripple in the total voltage and maintain high power transmission efficiency make the load R L Obtain higher quality, low interference stable DC output, improve power supply stability, and help meet the power supply requirements of precision loads and high-reliability electronic equipment.

[0174] More specifically, combined Figure 2 The structural setting of the above-mentioned wireless power transmission system is further explained: the first receiving module 31 and the second receiving module 32 have different circuit topology voltage output characteristics at the system operating frequency (i.e., resonant frequency), wherein, ignoring the parasitic internal resistance of the first receiving coil L2 and the second receiving coil L3, the first magnetic coupling resonant circuit and the second magnetic coupling resonant circuit constitute an LCC-S type resonant network, which is a constant voltage output, corresponding to the first voltage gain ;in, is the output voltage of the second magnetic coupling resonant circuit, is the input voltage of the first magnetic coupling resonant circuit, The first magnetic coupling resonant circuit and the third magnetic coupling resonant circuit form an LCC-LCC type resonant network, which is a constant current output, corresponding to the current gain. ;in, represents the mutual inductance between the transmitting coil L1 and the second receiving coil L3, is the inductance value of the second inductor Ls, represents the current flowing through the second inductor Ls, j represents a complex number; and since ,in, represents the output voltage of the third magnetic coupling resonant circuit, is the equivalent resistance at the output end of the third magnetic coupling resonant circuit, is the resonant angular frequency, then there is a corresponding second voltage gain , so that the output voltage of the second magnetic coupling resonant circuit The output voltage of the third magnetic coupling resonant circuit There is a 90° phase difference, and After passing through the first rectifier module 311, the first voltage After passing through the second rectifier module 321 and the voltage conversion module 322, the second voltage still maintains a phase difference of 90 degrees. With the help of the phase orthogonal interference mechanism, the ripple voltage amplitude of the total voltage after the first voltage and the second voltage are superimposed is effectively reduced, thereby improving the stability of the DC component of the total voltage, improving the power supply quality and the stability of the total output voltage. Figure 4 , Figure 4 A schematic diagram of a first voltage, a second voltage, and a total voltage varying with time provided by the present invention, wherein waveform A represents a waveform of the first voltage output by the first receiving module 31, waveform B represents a waveform of the second voltage output by the second receiving module 32, and waveform C represents the waveform of the first voltage and the second voltage superimposed and output to the load R. L The waveform of the total voltage is shown in the figure. The up and down fluctuations here are due to the ripple. It can be seen that after superposition, the ripple is suppressed and within an acceptable range.

[0175] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. Relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements limited by the sentence "comprising a" do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

[0176] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling power transmission, characterized in that: A control module applied to a wireless power transmission system, the wireless power transmission system further comprising a primary power transmitting module and a secondary power receiving module, the secondary power receiving module comprising a first receiving module and a second receiving module, the output end of the second receiving module being connected in reverse parallel to the output end of the first receiving module for connection to a load; the control module being connected to a controllable switch in a voltage conversion module in the second receiving module; the resonant frequency corresponding to power transmission by the primary power transmitting module being the same as the resonant frequency corresponding to power reception by the secondary power receiving module; The electric energy transmission control method comprises: S11: In the current control cycle, determining a preset duty cycle interval as a current search interval; S12: Determine a first test duty cycle and a second test duty cycle in the current search interval according to a test point selection strategy; S13: Determine, based on a preset enhanced ripple effective value determination strategy, a first ripple intensity corresponding to the total voltage output to the load at the first test duty cycle and a second ripple intensity corresponding to the total voltage at the second test duty cycle, so as to determine a test duty cycle corresponding to the smaller of the first ripple intensity and the second ripple intensity as a new endpoint value for duty cycle search; The step of determining a first ripple intensity corresponding to a total voltage output to the load at the first test duty cycle based on a preset enhanced ripple effective value determination strategy includes: determining a first PWM signal corresponding to the first test duty cycle, and controlling the controllable switch based on the first PWM signal; Obtaining N consecutive sampled voltages of the total voltage output to the load at a preset sampling frequency to obtain a voltage sample sequence, where N is an integer greater than 1; Performing sliding filtering on the voltage sample sequence to obtain a smoothed voltage sequence; determining an average DC component corresponding to the smoothed voltage sequence; Determine a difference between a smoothed voltage corresponding to an i-th voltage sampling point in a smoothed voltage sequence and the average DC component as a ripple deviation corresponding to the i-th voltage sampling point, where 1≤i≤N and i is an integer; The first ripple intensity corresponding to the total voltage output to the load under the first test duty cycle is determined according to a third preset relationship and the ripple deviation; the third preset relationship is: ； in, is the ripple deviation corresponding to the i-th voltage sampling point, represents the first ripple intensity; S14: Determine a new search interval based on the current search interval and the endpoint value, and use the new search interval as the current search interval; wherein the current search interval is [ , ], the new search interval is determined according to the current search interval and the endpoint value, including: when the first test duty cycle is the new endpoint value for duty cycle search, determining the left endpoint is and the right endpoint is the search interval of the first test duty cycle as the new search interval; when the second test duty cycle is the new endpoint value for duty cycle search, determine that the left endpoint is the second test duty cycle and the right endpoint is The search interval is the new search interval; S15: Determine whether the search termination condition is met; if not, return to S12; if so, determine a first target duty cycle based on the current search interval, so as to adjust the voltage ripple in the second voltage output by the second receiving module through the first target duty cycle, so that the voltage ripple intensity in the total voltage after the first voltage output by the first receiving module and the second voltage are superimposed is within a preset allowable range.

2. The power transmission control method according to claim 1, wherein: Step S12 includes: Determine a first test duty cycle according to the current search interval and a first preset relationship; The first preset relationship is: ； in, For the first test duty cycle, Indicates the right endpoint of the current search interval, Indicates the left endpoint of the current search interval, is the first preset parameter and 0< <1; Determine a second test duty cycle according to the current search interval and a second preset relationship; The second preset relationship is: ； in, represents the second test duty cycle.

3. The power transmission control method according to claim 1 or 2, characterized in that: After determining the first target duty cycle according to the current search interval, the method further includes: determining an adjusted basic duty cycle based on the first target duty cycle and its corresponding search interval, wherein the ripple intensity corresponding to the total voltage at the adjusted basic duty cycle is less than the ripple intensity corresponding to the total voltage at the first target duty cycle; The duty cycle is fine-tuned according to the preset fine search strategy and the adjusted basic duty cycle until a preset adjustment termination condition is reached, and the duty cycle at this time is determined to be the second target duty cycle.

4. The power transmission control method according to claim 3, wherein: Determining and adjusting the basic duty cycle based on the first target duty cycle and its corresponding search interval includes: S21: determining a dynamic step size update interval based on a search interval corresponding to the first target duty cycle, so as to determine a first adjustment step size according to the dynamic step size update interval; S22: Determine that a difference between the first target duty cycle and the first adjustment step is a first candidate duty cycle, and a sum of the first target duty cycle and the first adjustment step is a second candidate duty cycle; S23: Determine, based on the preset enhanced ripple effective value determination strategy, a third ripple intensity corresponding to the total voltage under the first candidate duty cycle and a fourth ripple intensity corresponding to the total voltage under the second candidate duty cycle; S24: Determine the smaller of the third ripple intensity and the fourth ripple intensity; S25: Determine whether the smaller one is smaller than the ripple intensity corresponding to the total voltage under the first target duty cycle; if so, proceed to S26; if not, proceed to S27; S26: Determine the candidate duty cycle corresponding to the smaller one as the basic duty cycle for adjustment; S27: re-determine a second adjustment step size according to the dynamic step size update interval, where the second adjustment step size is smaller than the first adjustment step size; use the second adjustment step size as a new first adjustment step size and return to S22.

5. The power transmission control method according to claim 3, wherein: Fine-tuning the duty cycle according to the preset fine search strategy and the adjusted basic duty cycle until a preset adjustment termination condition is reached, and determining the duty cycle at this time as a second target duty cycle, including: According to the first step length iterative relationship for determining the iterative step length in the j+1th search, the search is gradually conducted in the first direction starting from the regulated basic duty cycle until the fifth ripple intensity corresponding to the regulated basic duty cycle in the j+1th search is greater than the fifth ripple intensity corresponding to the regulated basic duty cycle in the jth search, and the regulated basic duty cycle in the jth search is determined to be a candidate duty cycle; wherein the first direction is the direction in which the first target duty cycle points to the regulated basic duty cycle, and the first step length iterative relationship is: ； represents the iterative step size for the j+1th search, represents the iterative step size under the j-th search, is the second preset parameter and , and is the third preset parameter, represents the right endpoint of the search interval corresponding to the first target duty cycle, represents the left endpoint of the search interval corresponding to the first target duty cycle; According to a second step length iterative relationship for determining an iterative step length in the s+1th search, a search is performed starting from the candidate duty cycle and stepping in a second direction until a preset adjustment termination condition is reached, whereupon the duty cycle at that time is determined to be a second target duty cycle; wherein the second direction is opposite to the first direction; and the second step length iterative relationship is: ； Indicates the iterative step size for the s+1th search, represents the iterative step size under the s-th search, is the fourth preset parameter and , and This is the fifth preset parameter.

6. A wireless power transmission system, characterized in that: It includes a primary power transmission module, a secondary power receiving module and a control module; the secondary power receiving module includes a first receiving module and a second receiving module, the output end of the second receiving module is connected in reverse parallel with the output end of the first receiving module and is used to connect to a load; the control module is connected to a controllable switch in a voltage conversion module in the second receiving module; the resonant frequency corresponding to the power transmission of the primary power transmission module is the same as the resonant frequency corresponding to the power reception of the secondary power receiving module; The control module is used to execute the steps of the power transmission control method according to any one of claims 1 to 5.

7. The wireless power transmission system according to claim 6, wherein: The primary power transmission module includes an inverter module, a first inductor, a first capacitor, a second capacitor, and a transmitting coil; the inverter module includes a first bridge arm and a second bridge arm arranged in parallel, and the first end of the first circuit formed by the parallel connection is connected to the positive output terminal of the power supply, and the second end of the first circuit is connected to the negative output terminal of the power supply; The first end of the transmitting coil is connected to one end of the first capacitor, and the second end is connected to one end of the second capacitor and the midpoint of the second bridge arm; One end of the first inductor is connected to the other end of the first capacitor and the other end of the second capacitor respectively, and the other end of the first inductor is connected to the midpoint of the first bridge arm.

8. The wireless power transmission system according to claim 7, wherein: The first receiving module includes a first receiving coil, a third capacitor, and a first rectifier module; the first rectifier module includes a third bridge arm and a fourth bridge arm arranged in parallel, and the first end of the second circuit formed by the parallel connection is connected to the second output end of the second receiving module, and the second end of the second circuit is connected to the first output end of the second receiving module; The first end of the first receiving coil is connected to one end of the third capacitor, and the second end is connected to the midpoint of the third bridge arm; The other end of the third capacitor is connected to the midpoint of the fourth bridge arm.

9. The wireless power transmission system according to claim 8, wherein: The second receiving module includes a second receiving coil, a fourth capacitor, a fifth capacitor, a second inductor, a second rectifier module, and a voltage conversion module; the second rectifier module includes a fifth bridge arm and a sixth bridge arm arranged in parallel, a first end of a third circuit formed by the parallel connection is connected to the first end of the voltage conversion module, and the common end of the connections serves as the first output end of the second receiving module, and a second end of the third circuit is connected to the second end of the voltage conversion module, and the common end of the connections serves as the second output end of the second receiving module; The control end of the controllable switch in the voltage conversion module is connected to the control module; A first end of the second receiving coil is connected to one end of the fourth capacitor, a second end is connected to one end of the fifth capacitor, and a common end of the connections is connected to the midpoint of the fifth bridge arm; One end of the second inductor is connected to the other end of the fourth capacitor and the other end of the fifth capacitor respectively, and the other end of the second inductor is connected to the midpoint of the sixth bridge arm.

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