Wide-range voltage regulation control method of LLC resonant conversion circuit and charging equipment

Abstract

The invention provides a wide-range voltage regulation control method of an LLC resonant conversion circuit and charging equipment. The method comprises the following steps: acquiring the current output voltage of the LLC resonant conversion circuit, and determining a corresponding frequency limit value based on the current output voltage; inputting the output voltage given value and the current output voltage into a frequency control loop of an LLC resonant conversion circuit, and calculating to obtain a switching frequency control quantity; and limiting the switching frequency control quantity by adopting the frequency limit value, and modulating by adopting the limited switching frequency control quantity so as to generate a pulse signal for controlling the LLC resonant conversion circuit. According to the method, the current switching frequency can be subjected to amplitude limiting based on the frequency limiting values corresponding to different voltages, the problem that the actual value of the output voltage deviates from the given value due to the fact that the frequency changes too fast and enters the capacitive interval of the LLC resonant conversion circuit is solved, and safe operation of the LLC resonant conversion circuit is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of LLC resonant conversion circuits, and in particular to a wide-range voltage regulation control method and charging equipment for LLC resonant conversion circuits. Background Art

[0002] The LLC resonant converter combines the advantages of the series resonant converter and the parallel resonant converter, and has the characteristics of wide output voltage range, high efficiency, low switching stress, low noise and low electromagnetic interference, etc. It realizes the opening and closing of the switch tube under zero voltage or zero current conditions through the resonance of the resonant inductor and the resonant capacitor, thereby significantly reducing the switching loss and improving the overall efficiency of the system.

[0003] At present, with the increasing demand for increasing the output voltage range of LLC resonant converters, the control strategy for a wide output voltage range also needs to be improved accordingly. When the output voltage range is large, in the process of controlling the actual output voltage value to adjust to the voltage set value, the switching frequency may enter the gain capacitive region due to the large adjustment range of the output voltage, causing the actual output voltage value and its changing trend to seriously deviate from the output voltage set value, and even create a risk of explosion. Summary of the invention

[0004] The present application provides a wide-range voltage regulation control method and a charging device for an LLC resonant conversion circuit to solve the problem of frequency regulation deviation of an LLC resonant converter with a wide output voltage range.

[0005] In a first aspect, the present application provides a wide range voltage regulation control method for an LLC resonant conversion circuit, comprising: Acquire a current output voltage of the LLC resonant conversion circuit, and determine a corresponding frequency limit value based on the current output voltage; Obtaining an output voltage given value, and inputting the output voltage given value and the current output voltage into a frequency control loop of an LLC resonant conversion circuit to calculate a switching frequency control amount; The switching frequency control amount is limited by using the frequency limit value, and the limited switching frequency control amount is used for modulation to generate a pulse signal for controlling the LLC resonant conversion circuit.

[0006] In a second aspect, the present application provides a terminal, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the method described in the first aspect or any possible implementation of the first aspect are implemented.

[0007] In a third aspect, an embodiment of the present application provides a charging device, comprising at least one charging module, wherein the charging module comprises an LLC resonant conversion circuit and a terminal as described in the second aspect above.

[0008] The embodiment of the present application provides a wide range voltage regulation control method and charging device of an LLC resonant conversion circuit. The method first obtains the current output voltage of the LLC resonant conversion circuit, determines the corresponding frequency limit value based on the current output voltage; then inputs the output voltage given value and the current output voltage into the frequency control loop of the LLC resonant conversion circuit, and calculates the switching frequency control amount; finally, the switching frequency control amount is limited by the frequency limit value, and the limited switching frequency control amount is used to generate a pulse signal for controlling the LLC resonant conversion circuit. The above method can limit the current switching frequency control amount based on the frequency limit values ​​corresponding to different voltages, so that the frequency modulation process of the loop can be compatible with the actual circuit output voltage adjustment process, avoid the frequency change too fast beyond the output voltage adjustment capacity of the circuit, so that the LLC resonant conversion circuit will not enter the capacitive interval under a certain process voltage in the process voltage adjustment interval during the voltage regulation process, resulting in excessive frequency modulation, and then causing the actual value of the output voltage and its change trend to seriously deviate from the given value, thereby ensuring the safe and stable operation of the LLC resonant conversion circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0010] Figure 1 It is a flow chart of the implementation of the wide range voltage regulation control method of the LLC resonant conversion circuit provided in the embodiment of the present application; Figure 2 is a schematic diagram of a gain-frequency curve provided in an embodiment of the present application; Figure 3 is a schematic diagram of a frequency control loop of an LLC resonant conversion circuit provided in an embodiment of the present application; Figure 4 It is a structural schematic diagram of a wide-range voltage regulation control device of an LLC resonant conversion circuit provided in an embodiment of the present application; Figure 5 It is a schematic diagram of a terminal provided in an embodiment of the present application. DETAILED DESCRIPTION

[0011] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0012] In the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0013] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0014] In addition, the “plurality” mentioned in the embodiments of the present application should be interpreted as two or more.

[0015] In order to make the purpose, technical solutions and advantages of the present application clearer, specific embodiments will be described below in conjunction with the accompanying drawings.

[0016] See also Figure 1 , which shows a flow chart of the implementation of the wide range voltage regulation control method of the LLC resonant conversion circuit provided by the embodiment of the present application, which is described in detail as follows: S101: Acquire a current output voltage of an LLC resonant conversion circuit, and determine a corresponding frequency limit value based on the current output voltage.

[0017] In this embodiment, Figure 2 The gain-frequency characteristic curve diagram of the LLC resonant conversion circuit corresponding to the two working conditions (output voltage Uo=650V and Uo=400V) provided in this embodiment is shown, with reference to Figure 2 The horizontal axis of the gain-frequency characteristic curve is the switching frequency, and the vertical axis is the voltage gain; different combinations of output voltage, output current and quality factor will result in different gain-frequency characteristic curves. Taking the gain characteristic curve of Uo=400V as an example, under normal circumstances, the LLC resonant conversion circuit is in the inductive range, that is, Figure 2In the right interval of the maximum frequency point 1 of the middle gain value, the inductive reactance is greater than the capacitive reactance, the feedback polarity of the LLC resonant conversion circuit is negative feedback, and the output voltage will increase with the decrease of the switching frequency; when the output voltage set value is much greater than the actual output voltage value, the switching frequency will change rapidly. When the actual output voltage value does not change in time, the switching frequency will decrease along the gain-frequency characteristic curve (Uo=400V) corresponding to the original output voltage. When the switching frequency decreases to the left side of the frequency 1 corresponding to the maximum gain value in the current gain-frequency characteristic curve, it will enter the capacitive interval of the LLC resonant conversion circuit. The capacitive reactance in this interval is greater than the inductive reactance. At this time, the feedback polarity of the LLC resonant conversion circuit is converted to positive feedback, that is, the output voltage will decrease with the decrease of the switching frequency. In this way, controlling the output voltage according to the original switching frequency control strategy will make the actual value far away from the set value, and even cause the machine to explode.

[0018] In order to solve the above problem, the present embodiment can set a frequency limit to limit the range of change of the switching frequency, avoid the problem of too fast change of the switching frequency causing change of feedback polarity, make the switching frequency change within a certain range, and after the actual value of the output voltage has completed the change, that is, after the gain-frequency characteristic curve changes to the curve corresponding to Uo=650V, the range of change of the switching frequency is correspondingly released, so that the output voltage gradually approaches the given value of the output voltage, reducing the risk of explosion caused by the actual value of the output voltage and its change trend seriously deviating from the given value of the output voltage.

[0019] Specifically, the controller of the LLC resonant conversion circuit uses a voltage transformer to collect the actual value of the output voltage of the LLC resonant conversion circuit in real time. Since different output voltages correspond to different gain curves, the frequency points corresponding to the corresponding maximum gain values ​​are also different. This embodiment can obtain the corresponding frequency limit based on the current actual value of the output voltage, and the frequency limit is greater than or equal to the frequency point corresponding to the maximum gain value.

[0020] S102: Inputting the output voltage set value and the current output voltage into a frequency control loop of an LLC resonant conversion circuit to calculate a switching frequency control value.

[0021] In this embodiment, the control loop of the LLC resonant conversion circuit can be a voltage loop, which inputs the current output voltage actual value and the current output voltage set value into the voltage loop, outputs the voltage loop control quantity, and converts the voltage loop control quantity into a switching frequency, and then generates a pulse signal based on the switching frequency, and sends the pulse signal to each switch tube of the LLC resonant conversion circuit to control the conduction and shutdown of each switch tube, thereby changing the output voltage of the LLC resonant conversion circuit.

[0022] The pulse signal may be a PWM (Pulse Width Modulation) signal, a PFM (Pulse Frequency Modulation) signal, or a combination of the two.

[0023] S103: using the frequency limit value to limit the switching frequency control amount, and using the limited switching frequency control amount for modulation to generate a pulse signal for controlling the LLC resonant conversion circuit.

[0024] It can be seen from the above embodiments that the above method can limit the current switching frequency control amount based on the frequency limit values ​​corresponding to different voltages, so that the frequency modulation process of the loop can be compatible with the actual circuit output voltage adjustment process, avoiding the frequency change too fast exceeding the output voltage adjustment capability of the circuit, so that the LLC resonant conversion circuit will not enter the capacitive interval under a certain process voltage in the process voltage regulation interval during the voltage regulation process, resulting in excessive frequency modulation, and further causing the actual value of the output voltage and its change trend to seriously deviate from the given value, thereby ensuring the safe and stable operation of the LLC resonant conversion circuit.

[0025] In a possible implementation, the specific implementation process of S101 includes: According to the corresponding relationship between the output voltage and the frequency limit, the frequency limit corresponding to the current output voltage is determined.

[0026] In a possible implementation manner, before S101, the method provided in this embodiment further includes: Obtaining a gain curve corresponding to the LLC resonant conversion circuit at different output voltages; Find the frequency corresponding to the maximum gain in the gain curve corresponding to each output voltage respectively, and use it as the inflection point frequency of the corresponding output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; For any output voltage, a frequency between the inflection point frequency corresponding to the output voltage and the operating frequency is selected as the frequency limit of the output voltage; Based on the frequency limit value corresponding to each output voltage, a corresponding relationship between the output voltage and the frequency limit value is established.

[0027] In this embodiment, firstly, based on the output voltage, output current and quality factor of the LLC resonant conversion circuit, the gain curve corresponding to the LLC resonant conversion circuit at different output voltages and output currents is drawn, and then the frequency corresponding to the maximum gain value in each gain curve is found, and the frequency is used as the inflection point frequency. The right side of the inflection point frequency is the inductive interval, and the left side is the capacitive interval. Therefore, it is necessary to set the frequency limit to a value greater than the inflection point frequency to prevent the switching frequency of the LLC resonant conversion circuit from changing to the capacitive area.

[0028] Specifically, after determining the minimum value of the frequency limit, it is also necessary to determine the maximum value of the frequency limit. In this embodiment, the operating frequency of the LLC resonant conversion circuit under the preset load is used as the maximum value of the frequency limit to avoid the problem that the actual value of the output voltage cannot be adjusted to a given value due to the frequency limit being too large. The preset load can be the real-time load of the LLC resonant conversion circuit or the full load.

[0029] Afterwards, when selecting the frequency limit between the operating frequency and the inflection point frequency, you can select any frequency between the operating frequency and the inflection point frequency as the frequency limit, or you can select a value at a specific position between the operating frequency and the inflection point frequency, such as the middle value of the operating frequency and the inflection point frequency, the value at 1 / 3, etc.; then construct a corresponding relationship between the output voltage and the frequency limit, and the corresponding relationship between the output voltage and the frequency limit can be a tabular corresponding relationship or a fitting formula, wherein the fitting formula is constructed with the output voltage as the independent variable and the frequency limit as the dependent variable.

[0030] In a possible implementation manner, before S101, another specific implementation process of the method for constructing the corresponding relationship between the output voltage and the frequency limit provided in this embodiment includes: Obtaining a gain curve corresponding to the LLC resonant conversion circuit at different output voltages; Find the frequency corresponding to the maximum gain in the gain curve corresponding to each output voltage respectively, and use it as the inflection point frequency of the corresponding output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; For any output voltage, a frequency between the inflection point frequency corresponding to the output voltage and the operating frequency is selected as the frequency limit of the output voltage; The full voltage range is divided into a plurality of voltage ranges, and a frequency limit value in each voltage range is selected as the frequency limit value corresponding to the voltage range; Based on the frequency limit of each voltage range, a corresponding relationship between the voltage range and the frequency limit is established.

[0031] In this embodiment, the voltage range of the LLC resonant conversion circuit is relatively wide. If the frequency limit is calculated for each output voltage, not only will the amount of calculation be large, but the frequency limit will also change frequently, resulting in unstable control.

[0032] In this embodiment, for an LLC resonant circuit with a wide voltage range, the experimental process of constructing a corresponding relationship between a voltage range and a frequency limit is as follows: First, the frequency corresponding to the maximum gain point of the output voltage is taken as the inflection point frequency. Based on the characteristic that the inflection point frequencies corresponding to similar output voltages are also relatively similar, the frequency at the maximum gain point corresponding to the full voltage range can be determined. Then, based on the frequency at the similar maximum gain point, the entire output voltage full range value is divided into multiple voltage ranges. For each voltage range, the maximum frequency at the maximum gain point corresponding to multiple output voltages in the voltage range is found. Then, the frequency limit corresponding to the voltage range is set to be greater than the maximum inflection point frequency corresponding to the voltage range, thereby obtaining the frequency limit corresponding to each voltage range, and determining and storing the corresponding relationship between the voltage range and the frequency limit. In the subsequent application process, after obtaining the current output voltage, the voltage range in which the current output voltage is located can be first determined, and then the frequency limit corresponding to the current voltage range can be determined based on the corresponding relationship between the voltage range and the frequency limit.

[0033] In this embodiment, another specific process of establishing the corresponding relationship between the voltage range and the frequency limit includes: After calculating the frequency limit corresponding to each output voltage, the frequency limits are clustered, and the voltage range of the frequency limit of this type is determined based on the output voltage corresponding to the frequency limit clustered into one type. The frequency limit corresponding to the cluster center is used as the frequency limit of this type, thereby determining the frequency limit of each voltage range within the full range, and then constructing the corresponding relationship between the voltage range and the frequency limit.

[0034] Specifically, a specific implementation method of selecting a frequency limit value in each voltage range as the frequency limit value corresponding to the voltage range may include: Select the frequency limit value that appears most frequently in each voltage range as the frequency limit value corresponding to the voltage range; Alternatively, the frequency limit value corresponding to the cluster center in each voltage range is selected as the frequency limit value corresponding to the voltage range.

[0035] In a possible implementation, the further implementation process of S101 includes: If the current output voltage is less than the given voltage value, the frequency limit value corresponding to the current output voltage is determined based on the first association relationship; the first association relationship is the correspondence between the output voltage and the frequency limit value when the output voltage is adjusted in the increasing direction; If the current output voltage is greater than the given voltage value, the frequency limit corresponding to the current output voltage is determined based on a second association relationship; the second association relationship is the correspondence between the output voltage and the frequency limit when the output voltage is adjusted in a decreasing direction.

[0036] In this embodiment, there are two situations for output voltage regulation. One is that the current output voltage is less than the given voltage value, then the current output voltage needs to be increased to approach the given voltage value. In this case, the first association relationship used is the corresponding relationship between the output voltage and the frequency limit values ​​constructed in the process of adjusting the output voltage from small to large. The other is that the current output voltage is greater than the given voltage value, then the current output voltage needs to be reduced to approach the given voltage value. In this case, the second association relationship used is the corresponding relationship between the output voltage and the frequency limit values ​​constructed in the process of adjusting the output voltage from large to small.

[0037] Correspondingly, the corresponding relationships between the output voltage and the frequency limit in the above two directions may also be corresponding relationships between the voltage range and the frequency limit.

[0038] Exemplarily, the output voltage range of the LLC resonant conversion circuit can be 100V~1000V. When the output voltage is adjusted in the increasing direction, the voltage range-frequency limit corresponding relationship is shown in Table 1. When the output voltage is adjusted in the decreasing direction, the voltage range-frequency limit corresponding relationship is shown in Table 2.

[0039] Table 1

[0040] Table 2

[0041] In one possible implementation, if the LLC resonant conversion circuit includes a full range of voltages in multiple gears, such as a high voltage gear (100V~1000V) and a low voltage gear (100V~500V), it is necessary to conduct experiments on the full range of voltage for each gear to divide the corresponding voltage range and frequency limit.

[0042] In a possible implementation manner, this embodiment can calculate the frequency limit value corresponding to the current output voltage in real time after acquiring the current output voltage. Specifically, another implementation process of S101 includes: Obtaining a gain curve of the LLC resonant conversion circuit at the current output voltage; Selecting the frequency with the largest gain value in the gain curve under the current output voltage as the inflection point frequency corresponding to the current output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; Any frequency between the inflection point frequency and the operating frequency is selected as the frequency limit corresponding to the current output voltage.

[0043] Specifically, the inflection point frequency may be multiplied by a preset coefficient to obtain a frequency limit corresponding to the current output voltage. The preset coefficient may be set between 1 and 1.15, and avoids the calculated frequency limit being greater than the operating frequency.

[0044] In a possible implementation, the specific implementation process of S103 includes: If the current output voltage is less than the voltage set value, the frequency limit value is used to limit the minimum value of the switching frequency control amount; If the current output voltage is greater than the voltage set value, the larger value between the frequency limit value and the switching frequency control amount is selected as the final switching frequency control amount.

[0045] In this embodiment, when the output voltage is adjusted in an increasing direction, the frequency limit is used to limit the switching frequency in the adjustment direction. When the output voltage is adjusted in a decreasing direction, the larger value of the frequency limit and the switching frequency control amount is selected. This can avoid the problem of the LLC resonant conversion circuit entering the capacitive range due to excessively fast switching frequency adjustment, thereby improving the safety of the wide range voltage regulation control of the LLC resonant conversion circuit.

[0046] In one possible implementation, Figure 3 FIG. 1 shows a wide range voltage regulation control loop diagram of the LLC resonant conversion circuit provided in this embodiment, referring to FIG. Figure 3 , the specific implementation process of S102 includes: Inputting the current output voltage into the voltage loop of the LLC resonant conversion circuit to obtain a voltage loop control amount; Acquiring a current output current of the LLC resonant conversion circuit, and inputting the current output current into a current loop of the LLC resonant conversion circuit to obtain a current loop control amount; The voltage loop control amount and the current loop control amount are input into a competition module to obtain a switching frequency control amount of the resonant conversion circuit.

[0047] Specifically, the actual value of the current output voltage U out And the output voltage given value U out-ref Input voltage loop, get voltage loop control quantity, and convert the actual value of current output current I out And the output current given value I out-refInput the current loop to obtain the current loop control amount, then input the voltage loop control amount and the current loop control amount into the competition module to obtain the switching frequency control amount, wherein the competition module can be set to take the smaller algorithm, that is, the smaller value of the voltage loop control amount and the current loop control amount is used as the switching frequency control amount. Then the switching frequency control amount is input into the modulation module to generate a PWM signal / PFM signal.

[0048] It can be seen from the above embodiments that this embodiment limits the switching frequency using frequency limits corresponding to different output voltage ranges, thereby avoiding the problem of the LLC resonant conversion circuit entering the capacitive range due to excessively fast switching frequency changes, so that the actual value of the output voltage follows the change in the switching frequency and then relaxes the frequency limit based on the actual value of the output voltage after the change, so that the output voltage gradually approaches the given value of the output voltage, thereby improving the wide range voltage regulation control stability of the LLC resonant conversion circuit.

[0049] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0050] The following is an embodiment of the device of the present application. For details not described in detail, please refer to the corresponding method embodiment described above.

[0051] Figure 4 The structure diagram of the wide range voltage regulation control device of the LLC resonant conversion circuit provided by the embodiment of the present application is shown. For the convenience of explanation, only the part related to the embodiment of the present application is shown, which is described in detail as follows: like Figure 4 As shown, the wide range voltage regulation control device 100 of the LLC resonant conversion circuit includes: A frequency limit value determination module 110 is used to obtain a current output voltage of the LLC resonant conversion circuit and determine a corresponding frequency limit value based on the current output voltage; The switching frequency determination module 120 is used to obtain a given output voltage value, and input the given output voltage value and the current output voltage into a frequency control loop of the LLC resonant conversion circuit to calculate a switching frequency control amount; The frequency limiting module 130 is used to limit the switching frequency control amount by using the frequency limit value, and to modulate the switching frequency control amount after the limit to generate a pulse signal for controlling the LLC resonant conversion circuit.

[0052] It can be seen from the above embodiments that the above device can limit the current switching frequency control amount based on the frequency limit values ​​corresponding to different voltages, so that the frequency modulation process of the loop can be compatible with the actual circuit output voltage adjustment process, avoiding the frequency change too fast exceeding the output voltage adjustment capability of the circuit, so that the LLC resonant conversion circuit will not enter the capacitive interval under a certain process voltage in the process voltage regulation interval during the voltage regulation process, resulting in excessive frequency modulation, and further causing the actual value of the output voltage and its change trend to seriously deviate from the given value, thereby ensuring the safe and stable operation of the LLC resonant conversion circuit.

[0053] In a possible implementation manner, the frequency limit value determining module 110 is specifically configured to: According to the corresponding relationship between the output voltage and the frequency limit, the frequency limit corresponding to the current output voltage is determined.

[0054] In a possible implementation, the wide-range voltage regulation control device 100 of the LLC resonant conversion circuit further includes a voltage-frequency relationship acquisition module, which is used to: Obtaining a gain curve corresponding to the LLC resonant conversion circuit at different output voltages; Find the frequency corresponding to the maximum gain in the gain curve corresponding to each output voltage respectively, and use it as the inflection point frequency of the corresponding output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; For any output voltage, a frequency between the inflection point frequency corresponding to the output voltage and the operating frequency is selected as the frequency limit of the output voltage; Based on the frequency limit value corresponding to each output voltage, a corresponding relationship between the output voltage and the frequency limit value is established.

[0055] In a possible implementation, the wide-range voltage regulation control device 100 of the LLC resonant conversion circuit further includes a voltage range-frequency relationship acquisition module, which is used to: Obtaining a gain curve corresponding to the LLC resonant conversion circuit at different output voltages; Find the frequency corresponding to the maximum gain in the gain curve corresponding to each output voltage respectively, and use it as the inflection point frequency of the corresponding output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; For any output voltage, a frequency between the inflection point frequency corresponding to the output voltage and the operating frequency is selected as the frequency limit of the output voltage; The full voltage range is divided into a plurality of voltage ranges, and a frequency limit value in each voltage range is selected as the frequency limit value corresponding to the voltage range; Based on the frequency limit of each voltage range, a corresponding relationship between the voltage range and the frequency limit is established.

[0056] In a possible implementation manner, the frequency limit value determining module 110 specifically includes: If the current output voltage is less than the given voltage value, the frequency limit value corresponding to the current output voltage is determined based on the first association relationship; the first association relationship is the correspondence between the output voltage and the frequency limit value when the output voltage is adjusted in the increasing direction; If the current output voltage is greater than the given voltage value, the frequency limit corresponding to the current output voltage is determined based on a second association relationship; the second association relationship is the correspondence between the output voltage and the frequency limit when the output voltage is adjusted in a decreasing direction.

[0057] In a possible implementation manner, the frequency limit value determining module 110 is specifically configured to: Obtaining a gain curve of the LLC resonant conversion circuit at the current output voltage; Selecting the frequency with the largest gain value in the gain curve under the current output voltage as the inflection point frequency corresponding to the current output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; Any frequency between the inflection point frequency and the operating frequency is selected as the frequency limit corresponding to the current output voltage.

[0058] In a possible implementation, the frequency limiting module 130 includes: If the current output voltage is less than the voltage set value, the frequency limit value is used to limit the minimum value of the switching frequency control amount; If the current output voltage is greater than the voltage set value, the larger value between the frequency limit value and the switching frequency control amount is selected as the final switching frequency control amount.

[0059] In a possible implementation, the switching frequency determination module 120 includes: Inputting the current output voltage into the voltage loop of the LLC resonant conversion circuit to obtain a voltage loop control amount; Acquiring a current output current of the LLC resonant conversion circuit, and inputting the current output current into a current loop of the LLC resonant conversion circuit to obtain a current loop control amount; The voltage loop control amount and the current loop control amount are input into a competition module to obtain a switching frequency control amount of the resonant conversion circuit.

[0060] Figure 5 is a schematic diagram of a terminal provided in an embodiment of the present application. Figure 5As shown, the terminal 5 of this embodiment includes: a processor 50, a memory 51, and a computer program 52 stored in the memory 51 and executable on the processor 50. When the processor 50 executes the computer program 52, the steps of the wide range voltage regulation control method embodiments of the above-mentioned LLC resonant conversion circuit are implemented, for example Figure 1 Alternatively, when the processor 50 executes the computer program 52, the functions of each module / unit in the above-mentioned device embodiments are realized, for example Figure 4 The functions of the modules 110 to 130 are shown.

[0061] Exemplarily, the computer program 52 may be divided into one or more modules / units, which are stored in the memory 51 and executed by the processor 50 to complete / implement the solution provided by the present application. The one or more modules / units may be a series of computer program instruction segments capable of completing specific functions, which are used to describe the execution process of the computer program 52 in the terminal 5.

[0062] The terminal 5 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The terminal 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art will appreciate that Figure 5 It is only an example of terminal 5 and does not constitute a limitation on terminal 5. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the terminal may also include input and output devices, network access devices, buses, etc.

[0063] The processor 50 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0064] The memory 51 may be an internal storage unit of the terminal 5, such as a hard disk or memory of the terminal 5. The memory 51 may also be an external storage device of the terminal 5, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. equipped on the terminal 5. Further, the memory 51 may include both an internal storage unit of the terminal 5 and an external storage device. The memory 51 is used to store the computer program and other programs and data required by the terminal. The memory 51 may also be used to temporarily store data that has been output or is to be output.

[0065] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0066] This embodiment provides an LLC resonant conversion circuit, which includes the terminal as described above.

[0067] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0068] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0069] In the embodiments provided in the present application, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0070] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0071] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0072] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the wide-range voltage regulation control method embodiment of each LLC resonant conversion circuit can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practices in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practices, computer-readable media does not include electrical carrier signals and telecommunication signals.

[0073] In addition, the embodiments shown in the drawings of the present application or the features of the various embodiments mentioned in this specification are not necessarily understood as independent embodiments. Instead, each feature described in one example of an embodiment can be combined with one or more other desired features from other embodiments to produce other embodiments not described in words or with reference to the drawings.

[0074] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A wide range voltage regulation control method for LLC resonant conversion circuit, characterized in that: include: Acquire a current output voltage of the LLC resonant conversion circuit, and determine a corresponding frequency limit value based on the current output voltage; Obtaining an output voltage given value, and inputting the output voltage given value and the current output voltage into a frequency control loop of an LLC resonant conversion circuit to calculate a switching frequency control amount; The switching frequency control amount is limited by using the frequency limit value, and the limited switching frequency control amount is used for modulation to generate a pulse signal for controlling the LLC resonant conversion circuit.

2. The wide range voltage regulation control method of LLC resonant conversion circuit according to claim 1, characterized in that: The determining the corresponding frequency limit value based on the current output voltage includes: According to the corresponding relationship between the output voltage and the frequency limit, the frequency limit corresponding to the current output voltage is determined.

3. The wide range voltage regulation control method of LLC resonant conversion circuit according to claim 2, characterized in that: Before determining the frequency limit value corresponding to the current output voltage according to the correspondence between the output voltage and the frequency limit value, the method further includes: Obtaining a gain curve corresponding to the LLC resonant conversion circuit at different output voltages; Find the frequency corresponding to the maximum gain in the gain curve corresponding to each output voltage respectively, and use it as the inflection point frequency of the corresponding output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; For any output voltage, a frequency between the inflection point frequency corresponding to the output voltage and the operating frequency is selected as the frequency limit of the output voltage; Based on the frequency limit value corresponding to each output voltage, a corresponding relationship between the output voltage and the frequency limit value is established.

4. The wide range voltage regulation control method of LLC resonant conversion circuit according to claim 2, characterized in that: Before determining the frequency limit value corresponding to the current output voltage according to the correspondence between the output voltage and the frequency limit value, the method further includes: Obtaining a gain curve corresponding to the LLC resonant conversion circuit at different output voltages; Find the frequency corresponding to the maximum gain in the gain curve corresponding to each output voltage respectively, and use it as the inflection point frequency of the corresponding output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; For any output voltage, a frequency between the inflection point frequency corresponding to the output voltage and the operating frequency is selected as the frequency limit of the output voltage; The full voltage range is divided into a plurality of voltage ranges, and a frequency limit value in each voltage range is selected as the frequency limit value corresponding to the voltage range; Based on the frequency limit of each voltage range, a corresponding relationship between the voltage range and the frequency limit is established.

5. The wide range voltage regulation control method of LLC resonant conversion circuit according to claim 2, characterized in that: The determining the frequency limit value corresponding to the current output voltage according to the corresponding relationship between the output voltage and the frequency limit value includes: If the current output voltage is less than the given voltage value, the frequency limit value corresponding to the current output voltage is determined based on the first association relationship; the first association relationship is the correspondence between the output voltage and the frequency limit value when the output voltage is adjusted in the increasing direction; If the current output voltage is greater than the given voltage value, the frequency limit corresponding to the current output voltage is determined based on a second association relationship; the second association relationship is the correspondence between the output voltage and the frequency limit when the output voltage is adjusted in a decreasing direction.

6. The wide range voltage regulation control method of LLC resonant conversion circuit according to claim 1, characterized in that: The determining the corresponding frequency limit value based on the current output voltage includes: Obtaining a gain curve of the LLC resonant conversion circuit at the current output voltage; Selecting the frequency with the largest gain value in the gain curve under the current output voltage as the inflection point frequency corresponding to the current output voltage; Obtaining an operating frequency of the LLC resonant conversion circuit under a preset load; Any frequency between the inflection point frequency and the operating frequency is selected as the frequency limit corresponding to the current output voltage.

7. The wide range voltage regulation control method of LLC resonant conversion circuit according to claim 1, characterized in that: The adopting the frequency limit value to limit the switching frequency control amount includes: If the current output voltage is less than the voltage set value, the frequency limit value is used to limit the minimum value of the switching frequency control amount; If the current output voltage is greater than the voltage set value, the larger value between the frequency limit value and the switching frequency control amount is selected as the final switching frequency control amount.

8. The wide range voltage regulation control method of LLC resonant conversion circuit according to claim 1, characterized in that: The step of inputting the output voltage given value and the current output voltage into the frequency control loop of the LLC resonant conversion circuit to calculate the switching frequency control amount includes: Inputting the current output voltage into the voltage loop of the LLC resonant conversion circuit to obtain a voltage loop control amount; Acquiring a current output current of the LLC resonant conversion circuit, and inputting the current output current into a current loop of the LLC resonant conversion circuit to obtain a current loop control amount; The voltage loop control amount and the current loop control amount are input into a competition module to obtain a switching frequency control amount of the resonant conversion circuit.

9. A terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the wide-range voltage regulation control method for the LLC resonant conversion circuit as described in any one of claims 1 to 8 are implemented.

10. A charging device, characterized in that: The device comprises at least one charging module, wherein the charging module comprises an LLC resonant conversion circuit and the terminal as claimed in claim 9.

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