Frequency modulation and phase shift hybrid modulation method of high-frequency LLC (Logical Link Control) and related device

Abstract

The invention provides a frequency modulation and phase shift hybrid modulation method for high-frequency LLC and a related device, which are applied to an LLC resonant converter and comprise the following steps: setting initial parameters of the LLC resonant converter; different system working frequencies are selected; for each system working frequency, determining a required phase shift angle according to a load demand and the system working frequency; and then judging whether the gain of the converter can meet the load requirement under the phase-shifting angle and the frequency, if not, adjusting the phase-shifting angle until the load requirement is met, and if so, taking the phase-shifting angle as a parameter combination. And then calculating system loss under parameter combinations corresponding to different frequencies, and finally selecting the combination with the minimum loss as a modulation parameter basis. The phase shift control is added on the basis of the traditional frequency modulation strategy, the output voltage can be accurately controlled without changing the topology of the converter, the influence of a dead zone under high frequency on the system is reduced, the optimal working point is determined through the balanced frequency modulation and phase shift strategy, the system loss is minimized, and the operation efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power conversion, and particularly relates to a frequency modulation and phase shift hybrid modulation method for high-frequency LLC and related devices. Background Art

[0002] LLC converters have advantages such as high efficiency, wide voltage output range, and high power density. They achieve the soft-switching function through the resonant working principle, significantly reducing switching losses, thereby improving the power conversion efficiency and being suitable for various power supply application scenarios. In addition, the high power density of LLC converters meets the requirements of miniaturization and portability of electronic devices. Through compact design and efficient energy conversion, high power output is achieved in a small space, greatly enhancing the power density. Therefore, LLC converters not only perform well in traditional AC-DC and DC-DC converters but also play an important role in emerging fields such as electric vehicle chargers, solar photovoltaic inverters, and wind power generation systems, with broad application prospects.

[0003] With the rapid development of the third-generation power semiconductor materials, especially GaN (gallium nitride) and SiC (silicon carbide) technologies, the operating frequency of switching power supplies has leaped from several hundred kHz to MHz. This frequency increase has promoted the miniaturization of key components such as inductors, capacitors, and transformers in power converters. However, with the continuous increase in the operating frequency, the limitations of traditional single modulation strategies have gradually emerged, making it difficult to meet the requirements of high-frequency application scenarios. For example, in a high-frequency operating environment, the proportion of dead time will increase, which will not only cause additional switching losses but also have a negative impact on the overall efficiency of the system. Current research mainly focuses on the impact on system gain when analyzing frequency modulation and phase shift control, while ignoring the balance problem between the two. Therefore, for high-frequency LLC converters, it is of great practical significance to study a hybrid modulation strategy that can minimize system losses. Summary of the Invention

[0004] In view of this, the present invention aims to provide a frequency modulation and phase shift hybrid modulation method for high-frequency LLC and related devices. By adopting a hybrid modulation strategy and comprehensively considering the complementary characteristics of frequency modulation and phase shift control, through precise parameter design and control algorithms, the efficient operation of LLC converters under high-frequency operating conditions is achieved, thereby effectively reducing system losses.

[0005] To achieve the above object, the technical solutions provided by the present invention are as follows:

[0006] In the first aspect, the present invention provides a frequency modulation and phase shift hybrid modulation method for high-frequency LLC, which is applied to an LLC resonant converter and includes the following steps:

[0007] Set the initial parameters of the LLC resonant converter;

[0008] Select different system operating frequencies;

[0009] For each system operating frequency, determine the required phase shift angle according to the load demand and the system operating frequency;

[0010] Based on the initial parameters, determine whether the gain of the LLC resonant converter meets the load demand at the determined phase shift angle and system operating frequency. If not, change the magnitude of the phase shift angle until the corresponding demand is met; if so, take the phase shift angle and system operating frequency as a parameter combination;

[0011] For different system operating frequencies, calculate the system losses under the corresponding parameter combinations;

[0012] Select the parameter combination with the minimum system loss as the parameter basis for the frequency modulation and phase shift hybrid modulation of the LLC resonant converter.

[0013] Furthermore, when selecting different system operating frequencies, at a set step size The initial frequency sequence for selecting the system operating frequency is , and ;

[0014] Then, for different system operating frequencies, calculate the system losses under the corresponding parameter combinations, including:

[0015] Calculate the three system losses under the parameter combinations corresponding to the frequency sequence , and in sequence as , and ;

[0016] Judge whether it satisfies , if so, delete the frequency and add a new frequency at the end of the sequence;

[0017] Recalculate whether the system losses of the new frequency sequence meet the corresponding relationship. If so, modify the frequency sequence until the corresponding relationship is met, and then output the parameter combination that minimizes the system losses.

[0018] Furthermore, when determining whether the gain of the LLC resonant converter meets the load demand, determine the gain according to the LLC gain function under the phase shift and frequency modulation hybrid modulation strategy. The LLC gain function is as follows:

[0019]

[0020] In the formula, and They are the gain function of the LLC controlled by the frequency modulation strategy and the gain function of the LLC under the phase-shifting and frequency modulation hybrid modulation strategy respectively; is the ratio of the switching frequency to the resonant frequency, is the ratio of the resonant inductor to the exciting inductor, is the load size; is the phase-shifting time, is the switching period.

[0021] Furthermore, the system loss includes the body diode loss of the MOS transistor for part of the time considering the dead time. The calculation expression of the body diode loss of the MOS transistor for part of the time considering the dead time is as follows:

[0022]

[0023] In the formula, is the body diode loss of the MOS transistor; is the dead time, is the phase-shifting time, is the input voltage, is the switching period, is the exciting inductor, is the forward voltage drop of the diode, is the time variable.

[0024] Furthermore, the system loss also includes the primary conduction loss considering only the fundamental wave. The calculation expression of the primary conduction loss considering only the fundamental wave is as follows:

[0025]

[0026] In the formula, is the primary conduction loss, is the switching period, is the current, is the angular frequency, is the phase-shifting time, is the input voltage, is the switching period, is the exciting inductor, is the resistance, is the time variable.

[0027] Furthermore, the LLC resonant converter includes:

[0028] A full-bridge inverter module for converting the DC input voltage into a high-frequency AC voltage;

[0029] A resonant module for stabilizing the high-frequency AC voltage;

[0030] A high-frequency transformer for stepping up or stepping down the high-frequency AC voltage on the input side;

[0031] A full-wave rectification system for converting the high-frequency AC voltage output by a high-frequency transformer into a DC voltage.

[0032] In a second aspect, the present invention provides a frequency modulation and phase shift hybrid modulation device for a high-frequency LLC, which is applied to an LLC resonant converter and includes:

[0033] A parameter setting module for setting the initial parameters of the LLC resonant converter; and also for selecting different system operating frequencies;

[0034] A phase shift angle module for determining the required phase shift angle according to the load demand and the system operating frequency for each system operating frequency;

[0035] A judgment module for judging whether the gain of the LLC resonant converter meets the load demand at the determined phase shift angle and system operating frequency based on the initial parameters. If not, the size of the phase shift angle is replaced until the corresponding demand is met; if so, the phase shift angle and the system operating frequency are used as a parameter combination;

[0036] A system loss calculation module for calculating the system loss under the corresponding parameter combination for different system operating frequencies;

[0037] A parameter selection module for selecting the parameter combination with the minimum system loss as the parameter basis for the frequency modulation and phase shift hybrid modulation of the LLC resonant converter.

[0038] In a third aspect, the present invention provides a frequency modulation and phase shift hybrid modulation system for a high-frequency LLC, which is implemented based on a frequency modulation and phase shift hybrid modulation method for a high-frequency LLC as in the first aspect and includes:

[0039] An LLC system and a control system;

[0040] The LLC system includes an LLC resonant converter for realizing DC / DC power conversion;

[0041] The control system includes a frequency modulation module and a phase shift modulation module;

[0042] The frequency modulation module and the phase shift modulation module are respectively used to realize the hybrid modulation of the LLC resonant converter according to the system operating frequency and the phase shift angle in the determined parameter combination.

[0043] In a fourth aspect, the present invention provides a computer device, which includes a processor and a memory:

[0044] The memory is used for storing a computer program and sending the instructions of the computer program to the processor;

[0045] The processor executes a frequency modulation and phase shift hybrid modulation method for a high-frequency LLC according to the instructions of a computer program as in the first aspect.

[0046] In a fifth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements a frequency modulation and phase shift hybrid modulation method for a high-frequency LLC as in the first aspect.

[0047] In summary, the present invention provides a frequency modulation and phase shift hybrid modulation method and related devices for a high-frequency LLC, which are applied to an LLC resonant converter, including setting initial parameters of the LLC resonant converter; selecting different system operating frequencies; for each system operating frequency, determining the required phase shift angle according to the load demand and the system operating frequency; based on the initial parameters, judging whether the gain of the LLC resonant converter meets the load demand at the determined phase shift angle and system operating frequency. If not, then change the magnitude of the phase shift angle until the corresponding demand is met; if so, then take the phase shift angle and the system operating frequency as a parameter combination; for different system operating frequencies, calculate the system losses under the corresponding parameter combinations; select the parameter combination with the minimum system loss as the parameter basis for the frequency modulation and phase shift hybrid modulation of the LLC resonant converter. The present invention introduces a phase shift control strategy on the basis of the traditional frequency modulation control strategy, and realizes precise control of the output voltage without changing the topology of the traditional LLC converter, reducing the influence of dead time on the system in the high-frequency case. At the same time, by balancing the frequency modulation and phase shift hybrid control strategy, the optimal operating point of the system is determined, realizing the minimization of system losses, thereby improving the overall operating efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0049] Figure 1 It is a flowchart of a frequency modulation and phase shift hybrid modulation method for a high-frequency LLC provided by an embodiment of the present invention;

[0050] Figure 2 It is a frequency modulation and phase shift hybrid modulation strategy diagram for LLC provided by an embodiment of the present invention;

[0051] Figure 3 It is a gain comparison diagram provided by an embodiment of the present invention;

[0052] Figure 4 It is a system loss diagram provided by an embodiment of the present invention;

[0053] Figure 5 Flow chart for determining the operating frequency and phase shift angle of the hybrid modulation method provided by the embodiment of the present invention;

[0054] Figure 6 Output waveform diagrams of different control strategies under full load provided by the embodiment of the present invention;

[0055] Figure 7 Output waveform diagrams of different control strategies under light load provided by the embodiment of the present invention;

[0056] Figure 8 Block diagram of the composition of a frequency modulation and phase shift hybrid modulation device for a high-frequency LLC provided by the embodiment of the present invention;

[0057] Figure 9 Block diagram of the composition of a computer device provided by the embodiment of the present invention. Detailed implementation manners

[0058] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0059] Please refer to Figure 1 , this embodiment provides a frequency modulation and phase shift hybrid modulation method for a high-frequency LLC, which is applied to an LLC resonant converter. The LLC resonant converter is a circuit topology that realizes efficient power conversion based on a resonant network composed of an inductor (L), a capacitor (C), and a transformer. It is commonly used in devices such as power adapters and industrial power supplies that need to convert DC voltage, and can achieve soft switching through resonance, reduce switching losses, and improve power conversion efficiency.

[0060] It includes the following steps:

[0061] S1: Set the initial parameters of the LLC resonant converter.

[0062] It should be noted that the initial parameters include gain, power, resonant frequency, etc. The setting of these parameters is based on the voltage and power requirements of the load and the objectives of the circuit design. For example, the gain can be determined according to the required output voltage of the load and the known input voltage; the power parameter can be determined according to the power requirement of the load; and the resonant frequency is determined by the values of the inductor and capacitor in the circuit.

[0063] This step can provide a basis for subsequent operations such as selecting the system operating frequency and calculating the phase shift angle, ensuring that the design and operation of the converter can meet the basic requirements of the load.

[0064] S2: Select different system operating frequencies.

[0065] It should be noted that the selection range of the system operating frequency is usually determined according to the characteristics of circuit components and design requirements. Different operating frequencies will affect the gain, loss, and soft-switching implementation conditions of the converter. For example, when the operating frequency is close to the resonance frequency, the converter may have better gain characteristics and soft-switching conditions.

[0066] By selecting multiple different operating frequencies in this step, the system performance at different frequencies can be compared in subsequent steps to find the optimal operating frequency.

[0067] S3: For each system operating frequency, determine the required phase shift angle according to the load demand and the system operating frequency.

[0068] It should be noted that based on the load demand (such as load current and output voltage requirements) and the currently selected system operating frequency, an initial phase shift angle can be selected.

[0069] S4: Based on the initial parameters, determine whether the gain of the LLC resonant converter meets the load demand at the determined phase shift angle and system operating frequency. If not, change the magnitude of the phase shift angle until the corresponding demand is met; if so, take the phase shift angle and system operating frequency as a parameter combination.

[0070] It should be noted that according to the preset gain (determined based on the load's demand for output voltage and input voltage), by calculating or measuring the actual gain of the converter at the current phase shift angle and system operating frequency, it is judged whether it is consistent with the initially set gain. If not, adjust the phase shift angle because changing the phase shift angle will affect the energy transfer path and time, thereby changing the gain.

[0071] This step can ensure that the converter can provide an appropriate output voltage for the load at the selected operating frequency and phase shift angle. Only when the gain meets the load demand can the normal operation of the load be guaranteed.

[0072] S5: Calculate the system losses under the corresponding parameter combinations for different system operating frequencies.

[0073] It should be noted that the system losses can include the switching losses and conduction losses of the switching transistors, as well as the losses of magnetic components such as transformers and inductors. For each selected operating frequency and the corresponding phase shift angle that meets the gain requirement (i.e., the parameter combination), the system losses are calculated through relevant loss calculation formulas. These formulas are usually based on factors such as the parameters of circuit components (such as the on-resistance of the switching transistors, the equivalent resistance of the transformers, etc.), the operating frequency, and the phase shift angle.

[0074] This step can evaluate the energy loss situation of the system under different combinations of operating frequencies and phase shift angles, so as to find the combination with the minimum loss and improve the efficiency of the converter.

[0075] S6: Select the parameter combination with the minimum system loss as the parameter basis for the frequency modulation and phase shift hybrid modulation of the LLC resonant converter.

[0076] It should be noted that by comparing the system losses calculated at different operating frequencies, the combination of the operating frequency and the phase shift angle that minimizes the system loss is selected. In a power electronics system, reducing the system losses can improve the efficiency of the converter, reduce heat generation, and improve the reliability and service life of the system.

[0077] This step can determine the optimal frequency modulation and phase shift hybrid modulation parameters, enabling the LLC resonant converter to operate with the highest efficiency while meeting the load voltage requirements.

[0078] This embodiment provides a frequency modulation and phase shift hybrid modulation method for high-frequency LLC. Based on the operating principle and performance characteristics of the LLC resonant converter, by systematically changing the operating frequency and the phase shift angle, and combining the evaluation of gain and loss, the operating parameters that enable the converter to achieve the lowest loss under the premise of meeting the load requirements are found. This method comprehensively considers two key aspects: voltage regulation (through gain control) and efficiency improvement (through loss minimization) of the converter.

[0079] This embodiment adopts the frequency modulation and phase shift hybrid modulation method, which can adjust the performance of the converter more flexibly compared with single frequency modulation or phase shift control. By combining the advantages of the two control methods, efficient and stable operation can be achieved within a wider load range and input voltage variation range. At the same time, selecting the parameter combination with the minimum system loss as the goal helps to significantly improve the power conversion efficiency of the LLC resonant converter. In the context of the increasing demand for power supply efficiency currently, this method has important practical value.

[0080] As Figure 2 shown, Figure 2 illustrates the LLC frequency modulation and phase shift hybrid modulation strategy, which is based on the LLC resonant converter ( Figure 2The upper part). The following introduces other embodiments of the present invention in conjunction with the LLC resonant converter shown in the figure.

[0081] In one embodiment, when determining whether the gain of the LLC resonant converter meets the load demand, the gain is determined according to the LLC gain function under the hybrid modulation strategy of phase shift and frequency modulation.

[0082] According to the analysis of the operating state of the LLC resonant converter under the hybrid modulation strategy of frequency modulation and phase shift, the voltage across the transformer can be expressed as:

[0083] (1)

[0084] The input voltage is Fourier-transformed to obtain the fundamental voltage as follows:

[0085] (2)

[0086] Therefore, the LLC gain function under the hybrid modulation strategy of phase shift and frequency modulation is:

[0087] (3)

[0088] In the formula, and are the gain functions of controlling LLC by the frequency modulation strategy and the LLC gain function under the hybrid modulation strategy of phase shift and frequency modulation, respectively; is the ratio of the switching frequency to the resonant frequency, is the ratio of the resonant inductance to the magnetizing inductance, is the load size; is the phase shift time, is the switching period.

[0089] Comparing the above formula with the gain function of controlling LLC by the traditional frequency modulation strategy, as Figure 3 shown. In the traditional frequency modulation control strategy (as Figure 3 (a) shown), the gain M1 is only related to the frequency ratio f n . That is, to control the output voltage, it can only be achieved by adjusting the frequency. However, the adjustment of the frequency may be restricted by factors such as the characteristics of circuit components (such as the limitation of the resonant frequency) and electromagnetic compatibility (EMC) requirements, resulting in difficulty in accurately controlling the output voltage in some cases. While in the hybrid control strategy (as Figure 3 (b) shown), the gain M2 is not only related to the frequency ratio f nIt is related to the phase shift time T1 in addition to the frequency. This provides an additional degree of control freedom. By adjusting the frequency and phase shift time simultaneously, the gain can be controlled more flexibly, thereby achieving precise control of the output voltage. For example, when the frequency ratio is near a specific value, the gain can be finely adjusted by fine-tuning the phase shift time, and then the output voltage can be precisely controlled. It can be seen that adding the phase shift control method can achieve precise control of the output voltage.

[0090] In one embodiment, the system loss includes the body diode loss of the MOS transistor during part of the dead time. The calculation expression for the body diode loss of the MOS transistor during part of the dead time is as follows:

[0091] (4)

[0092] In the formula, is the body diode loss of the MOS transistor; is the dead time, is the phase shift time, is the input voltage, is the switching period, is the exciting inductance, is the forward voltage drop of the diode, is the time variable.

[0093] In one embodiment, the system loss also includes the primary conduction loss considering only the fundamental wave. The calculation expression for the primary conduction loss considering only the fundamental wave is as follows:

[0094] (5)

[0095] In the formula, is the primary conduction loss, is the switching period, is the current, is the angular frequency, is the phase shift time, is the input voltage, is the switching period, is the exciting inductance, is the resistance, is the time variable.

[0096] According to formulas (4) and (5), draw the relationship diagram between the phase shift angle and the system loss, as Figure 4 shown, where the horizontal axis is the phase shift angle and the vertical axis is the system loss value. Analyze Figure 4It can be seen that when the phase-shift angle is 0, the system adopts a single frequency modulation control strategy, and the system loss is the largest. After that, the system loss will first decrease and then increase with the increase of the phase-shift angle, forming a "U" curve, that is, when the hybrid modulation strategy is adopted, the system loss can be effectively reduced, and there is an optimal phase-shift angle, which can balance the frequency modulation and phase-shift control strategies, minimize the loss of the LLC converter, and correspond to the high-efficiency operating point.

[0097] In one embodiment, when selecting different system operating frequencies, according to the set step size The initial frequency sequence for selecting the system operating frequency is 、 and ; then for different system operating frequencies, calculate the system losses under the corresponding parameter combinations, including:

[0098] 1) Calculate the three system losses under the parameter combinations corresponding to the frequency sequence 、 and in sequence as 、 and ;

[0099] 2) Judge whether it satisfies , if so, delete the frequency and add a new frequency at the end of the sequence;

[0100] 3) Recalculate whether the system loss of the new frequency sequence satisfies the corresponding relationship. If so, modify the frequency sequence until it satisfies the corresponding relationship, and then output the parameter combination that minimizes the system loss.

[0101] Figure 5 r is the flowchart of the specific implementation method of the high-frequency LLC frequency modulation and phase-shift hybrid modulation strategy. The core purpose of this process is to ensure efficient energy conversion of the LLC converter under different loads and operating conditions by optimizing system parameters. First, set the initial system parameter gains M, power P, and resonant frequency f r r , which are used to guide subsequent frequency selection and modulation strategies. On this basis, select an appropriate system operating frequency f. The selection of the operating frequency should not only match the resonant frequency f

[0102] In one embodiment, the LLC resonant converter includes: a full-bridge inverter module for converting a DC input voltage into a high-frequency AC voltage; a resonant module for stabilizing the high-frequency AC voltage; a high-frequency transformer for stepping up or stepping down the high-frequency AC voltage on the input side; and a full-wave rectification system for converting the high-frequency AC voltage output by the high-frequency transformer into a DC voltage.

[0103] For the frequency modulation and phase-shift hybrid modulation method of the high-frequency LLC proposed in the above embodiment, the frequency modulation control strategy and the hybrid modulation strategy are respectively used for testing, and the output voltage and current waveforms are as Figure 6 、 Figure 7 shown, where Figure 6 (a) and Figure 6 (b) are the output voltage and current of the frequency modulation control under full load, Figure 6 (c) and Figure 6 (d) are the output voltage and current of the hybrid control under full load; Figure 7 (a) and Figure 7 (b) are the output voltage and current of the frequency modulation control under light load, Figure 7 (c) and Figure 7 (d) are the output voltage and current of the hybrid control under light load.

[0104] Under light load, the output power of the frequency modulation control strategy is 56.31 W, the system loss is 4.6 W, and the system efficiency is 92.44%; the output power of the hybrid modulation strategy is 56.41 W, the system loss is 4 W, and the system efficiency is 93.28%, with an efficiency improvement of 0.84%.

[0105] The experimental results show that, compared with the traditional frequency modulation control strategy, the hybrid modulation strategy proposed by the present invention can effectively reduce the system loss and improve the system efficiency, especially under light load conditions, where the advantage is more obvious. This is mainly attributed to the fact that the hybrid modulation strategy can effectively balance the frequency modulation and phase-shift control strategies, reduce the loss of the MOS body diode and the on-resistance while ensuring the output voltage gain, thereby improving the system efficiency.

[0106] The present invention is applicable to the LLC resonant converter system considering dead time. By introducing a phase-shift control strategy on the basis of the traditional frequency modulation control strategy, precise control of the output voltage can be achieved without changing the topology of the traditional LLC converter, and the influence of dead time on the system under high frequency can be reduced. At the same time, by balancing the frequency modulation and phase-shift hybrid control strategy, the optimal operating point of the system is determined, and the minimization of the system loss is realized, thereby improving the overall operating efficiency of the system.

[0107] Based on the same inventive concept, an embodiment of the present application further provides a high-frequency LLC frequency modulation and phase-shift hybrid modulation device for implementing the high-frequency LLC frequency modulation and phase-shift hybrid modulation method involved above. The implementation solution provided by this device to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations in the embodiment of the high-frequency LLC frequency modulation and phase-shift hybrid modulation device provided below can refer to the limitations on the high-frequency LLC frequency modulation and phase-shift hybrid modulation method in the above text, and will not be repeated here.

[0108] Please refer to Figure 8 , an embodiment of the present invention further provides a high-frequency LLC frequency modulation and phase-shift hybrid modulation device, which is applied to an LLC resonant converter and includes:

[0109] A parameter setting module, configured to set the initial parameters of the LLC resonant converter; and is also configured to select different system operating frequencies;

[0110] A phase-shift angle module, configured to determine the required phase-shift angle according to the load demand and the system operating frequency for each system operating frequency;

[0111] A judgment module, configured to judge whether the gain of the LLC resonant converter meets the load demand at the determined phase-shift angle and system operating frequency based on the initial parameters. If not, the size of the phase-shift angle is replaced until the corresponding demand is met; if so, the phase-shift angle and the system operating frequency are used as a parameter combination;

[0112] A system loss calculation module, configured to calculate the system loss under the corresponding parameter combination for different system operating frequencies;

[0113] A parameter selection module, configured to select the parameter combination with the minimum system loss as the parameter basis for the frequency modulation and phase-shift hybrid modulation of the LLC resonant converter.

[0114] An embodiment of the present invention further provides a high-frequency LLC frequency modulation and phase-shift hybrid modulation system, which is implemented based on a high-frequency LLC frequency modulation and phase-shift hybrid modulation method as described in the foregoing embodiment, and includes: an LLC system and a control system;

[0115] The LLC system includes an LLC resonant converter for implementing DC / DC power conversion;

[0116] The control system includes a frequency modulation module and a phase-shift modulation module;

[0117] The frequency modulation module and the phase-shift modulation module are respectively configured to implement hybrid modulation of the LLC resonant converter according to the system operating frequency and the phase-shift angle in the determined parameter combination.

[0118] Please refer to again Figure 2 , Figure 2It includes an LLC system, which includes a full-bridge inverter module, a resonant module, a high-frequency transformer, and a full-wave rectification system, and is used to realize DC / DC power conversion; a control system, which includes a voltage and current sampling module to collect the output voltage and current, a PID control module to realize the closed-loop control of the system, a frequency comparison link for frequency control, and a delay module for PWM wave delay to realize the phase-shift control of the system. This modulation strategy realizes the precise regulation of the output voltage by integrating phase-shift control on the basis of the traditional frequency modulation (PFM) technology. In addition, the modulation strategy effectively reduces the system loss by balancing the ratio of frequency modulation and phase-shift control, especially effectively improves the efficiency under light load conditions. Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the above-mentioned division of each functional unit and module is used for illustration. In practical applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the system is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0119] Referring to Figure 9 , an embodiment of the present invention further provides a computer device, including: a memory, a processor, and a computer program stored on the memory. When the computer program is executed on the processor, it realizes the frequency modulation and phase-shift hybrid modulation method of high-frequency LLC as described in any one of the above methods.

[0120] The computer device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The computer device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that Figure 9 merely examples of computer devices do not constitute a limitation on computer devices, and may include more or fewer components than shown in the figure, or combine some components, or different components. For example, it may also include input / output devices, network access devices, etc.

[0121] The so-called processor may be a Central Processing Unit (CPU), and the processor may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0122] In some embodiments, the memory may be an internal storage unit of the computer device, such as the hard disk or memory of the computer device. In other embodiments, the memory may also be an external storage device of the computer device, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, etc. equipped on the computer device. Further, the memory may also include both the internal storage unit and the external storage device of the computer device. The memory is used to store an operating system, application programs, a BootLoader, data, and other programs, such as the program code of the computer program, etc. The memory may also be used to temporarily store data that has been output or is to be output.

[0123] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is run by a processor, it implements the frequency modulation and phase shift hybrid modulation method of high-frequency LLC as described in any one of the above methods.

[0124] In this embodiment, if the integrated 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, to implement all or part of the processes in the above embodiment methods of this application, a computer program can be used to instruct relevant hardware to complete. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can at least include: any entity or device capable of carrying the computer program code to the photographing device / terminal device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk, or an optical disc, etc. In some jurisdictions, according to legislation and patent practice, the computer-readable medium cannot be an electrical carrier signal and a telecommunication signal.

[0125] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0126] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

[0127] In the embodiments disclosed in this application, it should be understood that the disclosed device / terminal device and method can be implemented in other ways. For example, the device / terminal device embodiments described above are merely illustrative. For example, the division of the modules or units is only a logical function division. In actual implementation, there can be other division methods. For example, 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 displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0128] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A frequency modulation and phase shift hybrid modulation method for high-frequency LLC, characterized in that, Applied to an LLC resonant converter, it includes the following steps: Set the initial parameters of the LLC resonant converter; Select different system operating frequencies; For each of the system operating frequencies, determine the required phase shift angle according to the load demand and the system operating frequency; Based on the initial parameters, determine whether the gain of the LLC resonant converter meets the load demand at the determined phase shift angle and system operating frequency. If not, change the magnitude of the phase shift angle until the corresponding demand is met; if so, take the phase shift angle and the system operating frequency as a parameter combination; For different system operating frequencies, calculate the system losses under the corresponding parameter combinations; Select the parameter combination with the minimum system loss as the parameter basis for the frequency modulation and phase shift hybrid modulation of the LLC resonant converter.

2. The frequency modulation and phase shift hybrid modulation method of the high-frequency LLC according to claim 1, characterized in that When selecting different system operating frequencies, according to the set step size The initial frequency sequence for selecting the system operating frequency is , and ; Then, for different system operating frequencies, calculate the system losses under the corresponding parameter combinations, including: Calculate the three system losses under the parameter combinations corresponding to the frequency sequences , and in sequence, which are , and ; Determine whether it meets , if so, delete the frequency and add a new frequency at the end of the sequence ; Recalculate whether the system losses of the frequency sequence of the newly added frequency meet the corresponding relationship. If so, modify the frequency sequence until the corresponding relationship is met, and then output the parameter combination that minimizes the system losses.

3. The frequency modulation and phase shift hybrid modulation method of the high-frequency LLC according to claim 1, characterized in that, When determining whether the gain of the LLC resonant converter meets the load demand, determine the gain according to the LLC gain function under the phase shift and frequency modulation hybrid modulation strategy. The LLC gain function is as follows: Wherein, and are the gain functions of the LLC controlled by the frequency modulation strategy and the LLC gain function under the phase-shift and frequency modulation hybrid modulation strategy, respectively; is the ratio of the switching frequency to the resonant frequency, is the ratio of the resonant inductor to the exciting inductor, is the load size; is the phase-shift time, is the switching period.

4. The frequency modulation and phase shift hybrid modulation method of the high-frequency LLC according to claim 1, characterized in that, The system losses include the body diode losses of the MOS tube during part of the time considering the dead zone. The calculation expression of the body diode losses of the MOS tube during part of the time considering the dead zone is as follows: Wherein, is the MOS body diode loss; is the dead time, is the phase-shift time, is the input voltage, is the switching period, is the exciting inductance, is the forward voltage drop of the diode, is the time variable.

5. The frequency modulation and phase shift hybrid modulation method of the high-frequency LLC according to claim 1, characterized in that, The system losses also include the primary side conduction losses considering only the fundamental wave. The calculation expression of the primary side conduction losses considering only the fundamental wave is as follows: Wherein, is the primary side conduction loss, is the switching period, is the current, is the angular frequency, is the phase-shift time, is the input voltage, is the switching period, is the exciting inductance, is the resistance, is the time variable.

6. The frequency modulation and phase shift hybrid modulation method of the high-frequency LLC according to claim 1, characterized in that, The LLC resonant converter includes: A full-bridge inverter module for converting the DC input voltage into a high-frequency AC voltage; A resonant module for stabilizing the high-frequency AC voltage; A high-frequency transformer for stepping up or stepping down the high-frequency AC voltage on the input side; A full-wave rectification system for converting the high-frequency AC voltage output by the high-frequency transformer into a DC voltage.

7. A frequency modulation and phase shift hybrid modulation device for high-frequency LLC, characterized in that Applied to an LLC resonant converter, it includes: A parameter setting module for setting the initial parameters of the LLC resonant converter; and also for selecting different system operating frequencies; A phase shift angle module for determining the required phase shift angle according to the load demand and the system operating frequency for each of the system operating frequencies; A judgment module for determining whether the gain of the LLC resonant converter meets the load demand based on the initial parameters at the determined phase shift angle and system operating frequency. If not, change the magnitude of the phase shift angle until the corresponding demand is met; if so, take the phase shift angle and the system operating frequency as a parameter combination; A system loss calculation module for calculating the system losses under the corresponding parameter combinations for different system operating frequencies; A parameter selection module for selecting the parameter combination with the minimum system loss as the parameter basis for the frequency modulation and phase shift hybrid modulation of the LLC resonant converter.

8. A frequency modulation and phase shift hybrid modulation system for high-frequency LLC, which is implemented based on a frequency modulation and phase shift hybrid modulation method for high-frequency LLC according to any one of claims 1-6, characterized in that It includes: LLC system and control system; The LLC system includes an LLC resonant converter for realizing DC / DC power conversion; The control system includes a frequency modulation module and a phase shift modulation module; The frequency modulation module and the phase shift modulation module are respectively used to realize hybrid modulation of the LLC resonant converter according to the system operating frequency and phase shift angle in the determined parameter combination.

9. A computer device, characterized in that, The device includes a processor and a memory: The memory is used to store a computer program and send instructions of the computer program to the processor; The processor executes, according to the instructions of the computer program, a method for hybrid frequency modulation and phase shift of a high-frequency LLC as described in any one of claims 1-6.

10. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by the processor, a method for hybrid frequency modulation and phase shift of a high-frequency LLC as described in any one of claims 1-6 is realized.

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