Start control method of LLC converter

Abstract

The invention discloses a starting control method of an LLC converter. The method comprises the following steps: acquiring resonant frequency and oscillation frequency of the LLC converter; determining a central angle corresponding to the LLC converter according to the resonant frequency, wherein the central angle is a central angle corresponding to an arc of a state track of the LLC converter; and calculating the starting frequency of the LLC converter by adopting the central angle and the oscillation frequency, and controlling the LLC converter to start according to the starting frequency. According to the invention, the resonant frequency and the oscillation frequency of the LLC converter can be obtained; determining a central angle corresponding to the LLC converter according to the resonant frequency; the starting frequency of the LLC converter is calculated through the central angle and the oscillation frequency, and the LLC converter is controlled to be started according to the starting frequency; according to the method, the starting frequency required by starting of the LLC converter can be accurately calculated, so that current and voltage stress are prevented from being generated in the resonant cavity, the LLC converter can be started more stably, and the output voltage of the LLC converter is more stable.

Description

Background Art

[0002] LLC converter, also known as LLC resonant converter, is a high-efficiency, low-voltage, high-frequency DC-DC converter. Its main working principle is to use a resonant network to achieve control circuit. The working topology of LLC converter is mainly composed of inductors, capacitors and transistors, among which inductors and capacitors form a resonant network, and transistors control the switch of the resonant network to achieve energy transfer.

[0003] In order to make the LLC converter operate near the resonant frequency point and maintain its optimal efficiency, the currently commonly used control method is to build the voltage from zero to a steady-state value to prevent it from entering the zero current switching region. During the hold time operation, its input voltage is reduced to keep the output voltage constant, thereby reducing the switching frequency, increasing the voltage gain, and allowing the LLC converter to maintain optimal efficiency.

[0004] However, the commonly used methods currently have the following technical problems: generally, large voltage and current stresses will be generated at the startup time. For example, during the soft start process, if the switching frequency drops too quickly, large voltage and current stresses will be generated, which will trigger overcurrent protection and affect the normal use of the LLC converter. Summary of the invention

[0005] The present invention provides a startup control method, device, equipment and medium for an LLC converter, which can solve the technical problem of generating large voltage and current stress during startup in the prior art.

[0006] A first aspect of an embodiment of the present invention provides a startup control method for an LLC converter, the method comprising:

[0007] Obtain the resonant frequency and oscillation frequency of the LLC converter;

[0008] Determine a center angle corresponding to the LLC converter according to the resonant frequency, wherein the center angle is a center angle corresponding to an arc of a state trajectory of the LLC converter;

[0009] The starting frequency of the LLC converter is calculated using the central angle and the oscillation frequency, and the LLC converter is controlled to start according to the starting frequency.

[0010] In combination with the first aspect, in one implementation, determining the center angle corresponding to the LLC converter according to the resonant frequency includes:

[0011] Extracting the switch on time from a state trajectory of the LLC converter, wherein the state trajectory is constructed based on the resonant inductor current and the resonant capacitor voltage of the LLC converter before the LLC converter is started;

[0012] The switch on time and the resonant frequency are used to calculate the center angle corresponding to the LLC converter.

[0013] In conjunction with the first aspect, in one implementation, the operation of constructing a state trajectory of the LLC converter includes:

[0014] Before the LLC converter is started, the resonant inductor current and the resonant capacitor voltage are obtained and normalized to obtain a normalized current and a normalized voltage;

[0015] After constructing a state plane with the normalized current as the abscissa and the normalized voltage as the ordinate, the normalized current and the normalized voltage are used to construct a trajectory equation of the LLC converter;

[0016] The trajectory of the trajectory equation in the state plane is determined to obtain the state trajectory.

[0017] In combination with the first aspect, in one implementation, the calculating the central angle corresponding to the LLC converter by using the switch on time and the resonant frequency includes:

[0018] According to the following formula, calculate the center angle corresponding to the LLC converter:

[0019]

[0020] Where T1 is the on-time of LLC converter switch Q1, T2 is the on-time of LLC converter switch Q2, ω0 is the resonant frequency, and the center angle of the LLC converter is

[0021] The resonant frequency ω0 is expressed as follows:

[0022]

[0023] L r is the resonant inductor, C r is the resonant capacitor.

[0024] In combination with the first aspect, in one implementation, the calculating the starting frequency of the LLC converter by using the central angle and the oscillation frequency includes:

[0025] The starting frequency of the LLC converter is calculated according to the following formula:

[0026]

[0027] In the above formula, f s_ini is the starting frequency, ω 0，m is the oscillation frequency, is the center angle corresponding to the LLC converter;

[0028] The oscillation frequency is expressed as follows:

[0029]

[0030] Among them, L r is the resonant inductor, C r,age is the capacitance value of the resonant capacitor after aging.

[0031] In conjunction with the first aspect, in one implementation, the operation of monitoring the capacitance value of the resonant capacitor after aging includes:

[0032] When the LLC converter is shut down and the LLC converter resonant cavity forms a discharge loop, the digital controller is called to sample the resonant current zero-crossing period T cm , and passes through the zero period T cm Calculate the capacitance value of the resonant capacitor after aging.

[0033] A second aspect of an embodiment of the present invention provides a startup control device for an LLC converter, the device comprising:

[0034] A frequency acquisition module is used to obtain the resonant frequency and oscillation frequency of the LLC converter;

[0035] A module for determining a center angle of a circle, used to determine a center angle of a circle corresponding to the LLC converter according to the resonant frequency, wherein the center angle of a circle is a center angle of a circular arc corresponding to a state trajectory of the LLC converter;

[0036] A starting module is used to calculate a starting frequency of the LLC converter by using the central angle and the oscillation frequency, and control the starting of the LLC converter according to the starting frequency.

[0037] In conjunction with the second aspect, in one implementation, determining the center angle corresponding to the LLC converter according to the resonant frequency includes:

[0038] Extracting the switch on time from a state trajectory of the LLC converter, wherein the state trajectory is constructed based on the resonant inductor current and the resonant capacitor voltage of the LLC converter before the LLC converter is started;

[0039] The switch on time and the resonant frequency are used to calculate the center angle corresponding to the LLC converter.

[0040] In conjunction with the second aspect, in one implementation, the operation of constructing a state trajectory of the LLC converter includes:

[0041] Before the LLC converter is started, the resonant inductor current and the resonant capacitor voltage are obtained and normalized to obtain a normalized current and a normalized voltage;

[0042] After constructing a state plane with the normalized current as the abscissa and the normalized voltage as the ordinate, the normalized current and the normalized voltage are used to construct a trajectory equation of the LLC converter;

[0043] The trajectory of the trajectory equation in the state plane is determined to obtain the state trajectory.

[0044] In conjunction with the second aspect, in one implementation, the calculating the center angle corresponding to the LLC converter by using the switch on time and the resonant frequency includes:

[0045] According to the following formula, calculate the center angle corresponding to the LLC converter:

[0046]

[0047] Where T1 is the on-time of LLC converter switch Q1, T2 is the on-time of LLC converter switch Q2, ω0 is the resonant frequency, and the center angle of the LLC converter is

[0048] The resonant frequency ω0 is expressed as follows:

[0049]

[0050] L r is the resonant inductor, C r is the resonant capacitor.

[0051] In conjunction with the second aspect, in one implementation, the calculating the starting frequency of the LLC converter by using the central angle and the oscillation frequency includes:

[0052] The starting frequency of the LLC converter is calculated according to the following formula:

[0053]

[0054] In the above formula, f s_ini is the starting frequency, ω 0，m is the oscillation frequency, is the center angle corresponding to the LLC converter;

[0055] The oscillation frequency is expressed as follows:

[0056]

[0057] Among them, L r is the resonant inductor, C r,age is the capacitance value of the resonant capacitor after aging.

[0058] In conjunction with the second aspect, in one implementation, the operation of monitoring the capacitance value of the resonant capacitor after aging includes:

[0059] When the LLC converter is shut down and the LLC converter resonant cavity forms a discharge loop, the digital controller is called to sample the resonant current zero-crossing period T cm , and passes through the zero period T cm Calculate the capacitance value of the resonant capacitor after aging.

[0060] Compared with the prior art, the startup control method, device, equipment and medium of an LLC converter provided by the embodiment of the present invention have the following beneficial effects: the present invention can obtain the resonant frequency and oscillation frequency of the LLC converter; determine the center angle corresponding to the LLC converter according to the resonant frequency; calculate the startup frequency of the LLC converter using the center angle and the oscillation frequency, and control the startup of the LLC converter according to the startup frequency. In the above manner, the startup frequency required for the LLC converter to start can be accurately calculated, thereby avoiding the generation of current and voltage stress in the resonant cavity, allowing the LLC converter to start more stably, and making the output voltage of the LLC converter more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a flow chart of a startup control method of an LLC converter provided by one embodiment of the present invention;

[0062] Figure 2 1 is a schematic diagram of a first operating mode of a circuit topology of an LLC converter provided by an embodiment of the present invention;

[0063] Figure 3 is a schematic diagram of a second operating mode of a circuit topology of an LLC converter provided by an embodiment of the present invention;

[0064] Figure 4 is a schematic diagram of a state trajectory of an LLC converter provided by an embodiment of the present invention;

[0065] Figure 5 It is a schematic diagram of limiting waveform of resonant current within a symmetrical current band during the startup process of an LLC converter provided by an embodiment of the present invention;

[0066] Figure 6 is a schematic diagram of an optimal state trajectory within a current limiting band as the output voltage increases, provided by an embodiment of the present invention;

[0067] Figure 7 It is a structural schematic diagram of a startup control device for an LLC converter provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] LLC converter, also known as LLC resonant converter, is a high-efficiency, low-voltage, high-frequency DC-DC converter. Its main working principle is to use a resonant network to achieve control circuit. The working topology of LLC converter is mainly composed of inductors, capacitors and transistors, among which inductors and capacitors form a resonant network, and transistors control the switch of the resonant network to achieve energy transfer.

[0070] In order to make the LLC converter operate near the resonant frequency point and maintain its optimal efficiency, the currently commonly used control method is to build the voltage from zero to a steady-state value to prevent it from entering the zero current switching region. During the hold time operation, its input voltage is reduced to keep the output voltage constant, thereby reducing the switching frequency, increasing the voltage gain, and allowing the LLC converter to maintain optimal efficiency.

[0071] However, the commonly used methods currently have the following technical problems: generally, large voltage and current stresses will be generated at the startup time. For example, during the soft start process, if the switching frequency drops too quickly, large voltage and current stresses will be generated, which will trigger overcurrent protection and affect the normal use of the LLC converter.

[0072] In order to solve the above problems, a startup control method, device, equipment and medium of an LLC converter provided in an embodiment of the present application will be introduced and explained in detail through the following specific embodiments.

[0073] Reference Figure 1 , shows a flow chart of a startup control method of an LLC converter provided by an embodiment of the present invention.

[0074] In one embodiment, the startup control method of the LLC converter may be applicable to a control system or a control device of the LLC converter.

[0075] Wherein, as an example, the startup control method of the LLC converter may include:

[0076] S11. Obtain the resonant frequency and oscillation frequency of the LLC converter.

[0077] In one embodiment, the resonant frequency and the oscillation frequency of the LLC converter may be acquired respectively, wherein the resonant frequency and the oscillation frequency may be the resonant frequency and the oscillation frequency before the LLC converter is started.

[0078] In one implementation, the resonant frequency is ω0, and the resonant frequency ω0 can be expressed as follows:

[0079]

[0080] In the above formula, L r is the resonant inductor, C r is the resonant capacitor.

[0081] Considering that the LLC converter will age due to long-term service, the resonant capacitor used in the oscillation frequency should adopt the actual capacitor aging value C r,age .

[0082] In one implementation, the oscillation frequency is ω 0，m , the oscillation frequency ω 0，m It can be shown as follows:

[0083]

[0084] Among them, L r is the resonant inductor, C r,age is the capacitance value of the resonant capacitor after aging.

[0085] Reference Figure 2-3 , respectively show a first operating mode schematic diagram of a circuit topology of an LLC converter provided in an embodiment of the present invention and a second operating mode schematic diagram of a circuit topology of an LLC converter provided in an embodiment of the present invention.

[0086] In order to accurately measure the real-time capacitance value of the resonant capacitor after aging, the operation of monitoring the capacitance value of the resonant capacitor after aging may include the following sub-steps, as an example:

[0087] When the LLC converter is shut down and the LLC converter resonant cavity forms a discharge loop, the digital controller is called to sample the resonant current zero-crossing period T cm , and passes through the zero period T cm Calculate the capacitance value of the resonant capacitor after aging.

[0088] Specifically, at the start-up time, there is no energy in the resonant cavity of the LLC converter, and the resonant inductor current and capacitor voltage of the LLC converter are both zero (i.e., Lr =0 and V Cr =0). Before operation, the output voltage of the LLC converter is zero. When the switch Q1 of the LLC converter is turned on for the first time, the equivalent circuit is as follows: Figure 2 shown.

[0089] During the shutdown process of the LLC converter, the LLC converter can Figure 2The mode switches to Figure 3 The resonant cavity forms an independent discharge loop and oscillates in the form of an oscillating current with an oscillation frequency ω 0，m The resonant current zero-crossing period T can be sampled by a digital controller cm Determine that the oscillation frequency ω 0，m It can be shown as follows:

[0090]

[0091] In actual use, since the inductance of magnetic components is usually not easy to change and can be ignored, the oscillation frequency ω 0，m In fact, due to the aging of the resonant capacitor, the oscillation frequency ω 0，m It can be shown as follows:

[0092]

[0093] S12. Determine a center angle corresponding to the LLC converter according to the resonant frequency, where the center angle is a center angle corresponding to an arc of a state trajectory of the LLC converter.

[0094] After obtaining the resonant frequency, the center angle corresponding to the LLC converter can be calculated using the resonant frequency. The center angle is the value of the LLC converter in the following example: Figure 2 and Figure 3 In the mode of , the center angle of the arc corresponding to its state trajectory.

[0095] Wherein, as an example, determining the center angle corresponding to the LLC converter according to the resonant frequency may include the following sub-steps:

[0096] S121. Extracting switch on time from a state trajectory of the LLC converter, wherein the state trajectory is constructed based on a resonant inductor current and a resonant capacitor voltage of the LLC converter before the LLC converter is started.

[0097] S122: Calculate the center angle corresponding to the LLC converter using the switch on time and the resonant frequency.

[0098] In one embodiment, it can be determined that the LLC converter is in a state such as Figure 2 The mode and Figure 3 In the mode of, the trajectory corresponding to its state is obtained, and the state trajectory can be determined specifically that the LLC converter is in the following state: Figure 2 The modal trajectory of the LLC converter is Figure 3 The mode trajectory is obtained by calculating the state trajectory. According to the time proportion of each mode trajectory in the state trajectory, the on-time of switch Q1 and switch Q2 is determined respectively to obtain the switch on-time.

[0099] Finally, the switch on-time and resonant frequency are used to calculate the center angle of the LLC converter.

[0100] Wherein, as an example, the calculating of the center angle corresponding to the LLC converter by using the switch on time and the resonant frequency may include the following sub-steps:

[0101] According to the following formula, calculate the center angle corresponding to the LLC converter:

[0102]

[0103] Where T1 is the on-time of LLC converter switch Q1, T2 is the on-time of LLC converter switch Q2, ω0 is the resonant frequency, and the center angle of the LLC converter is

[0104] In one embodiment, T1 = T2.

[0105] Wherein, as an example, the operation of constructing the state trajectory of the LLC converter may include the following sub-steps:

[0106] S21. Before starting the LLC converter, the resonant inductor current and the resonant capacitor voltage are obtained and normalized to obtain a normalized current and a normalized voltage.

[0107] S22. After constructing a state plane with the normalized current as the horizontal coordinate and the normalized voltage as the vertical coordinate, the normalized current and the normalized voltage are used to construct a trajectory equation of the LLC converter.

[0108] S23, determining the trajectory of the trajectory equation in the state plane to obtain a state trajectory.

[0109] Specifically, according to the above analysis, before starting, there is no energy in the resonant cavity of the LLC converter, and the resonant inductor current and resonant capacitor voltage of the LLC converter are both zero (i.e., Lr =0 and V Cr =0). in and current factor V in / Z(here ) for the resonant inductor current i Lr and the resonant capacitor voltage V Cr Normalization is performed as follows to obtain normalized current and normalized voltage. Specifically, the normalized current i LrN and the normalized voltage v CrN It can be shown as follows:

[0110] i LrN =i Lr Z / V in ;

[0111] v CrN =v Cr / V in ;

[0112] Then the normalized current i LrN is the horizontal axis, with normalized voltage v CrN As the ordinate, construct the state plane. At the start-up time, the initial point of the LLC converter's running trajectory is (0, 0). Before operation, the LLC converter's output voltage is zero. When the LLC converter's switch Q1 is turned on for the first time, the equivalent circuit is as follows: Figure 2 As shown, the voltage across the resonant circuit is V in , resonant inductor current i Lr and the resonant capacitor voltage V Cr The trajectory equation is shown as follows:

[0113] (v CrN -1) 2 +i LrN 2 =1.

[0114] Therefore, during the conduction period of switch Q1, the trajectory of the LLC converter is a circle with a center (1,0). In the half cycle of switch Q1 conduction, the operating point of the LLC converter moves from (0,0) to (2,0), that is, v CrN =2,i CrN = 0. Then, switch Q2 is turned on, as Figure 3 As shown. Since the output voltage of the LLC converter has not yet been established, the voltage across the entire resonant tank is 0, and the initial condition when the switch Q2 is turned on is v CrN =2,i CrN = 0. Correspondingly, on the state plane, the resonant inductor current i Lr and the resonant capacitor voltage V Cr The trajectory equation is shown as follows:

[0115] v CrN 2 +i LrN 2 =2 2 ;

[0116] Therefore, during the conduction period of switch Q2, the trajectory of the LLC converter is a trajectory circle with the center at (0,0). In the half cycle of switch Q2 conduction, the operating point of the LLC converter moves from (2,0) to (-2,0). In the entire cycle, the trajectory is from the initial point (0,0) through a semicircle with a radius of 1 to (2,0), and then from (2,0) through another semicircle with a radius of 2. The larger the radius of the circle, the greater the current and voltage stress in the resonant cavity.

[0117] By setting the resonant capacitor voltage V Cr Build to V in / 2, the current limit band is changed to be symmetrical (±I MAXN ) to maximize energy transfer. At the beginning, since the output voltage has not yet been established (i.e., V o =0), the centers of the trajectory circles are located at (0,0) and (1,0) respectively. In order to Lr Restricted within the symmetric band, two local arcs can be uniquely determined and the state trajectory of the LLC converter can be obtained.

[0118] Reference Figure 4 , which is a schematic diagram showing the state trajectory of an LLC converter provided by an embodiment of the present invention. The state trajectory of the LLC converter is as follows Figure 4 The conduction angle is shown as an ellipse. It can be defined as:

[0119]

[0120] according to Figure 4 The state trajectory of the arc is Therefore, the conduction time of Q1 and Q2 is the same, that is, the center angle corresponding to the LLC converter can be shown as follows:

[0121]

[0122] S13, using the central angle and the oscillation frequency to calculate a starting frequency of the LLC converter, and controlling the LLC converter to start according to the starting frequency.

[0123] In one embodiment, the step of calculating the starting frequency of the LLC converter by using the central angle and the oscillation frequency may include the following sub-steps:

[0124] The starting frequency of the LLC converter is calculated according to the following formula:

[0125]

[0126] In the above formula, f s_ini is the starting frequency, ω 0，m is the oscillation frequency, is the center angle of the LLC converter. Figure 5 , shows a schematic diagram of limiting waveform of the resonant current within the symmetrical current band during the startup process of the LLC converter provided by an embodiment of the present invention.

[0127] The corresponding time domain waveform is as follows Figure 5 The asymmetric band is set to establish the resonant capacitor voltage to Vin / 2. After that, the current limit is changed to a symmetrical frequency band. Among them, the above starting frequency is the best starting frequency, and the best judgment standard is the resonant current i Lr is well confined to a predetermined band, e.g. Figure 5 shown.

[0128] Reference Figure 6 , which shows a schematic diagram of the optimal state trajectory within the current limiting band as the output voltage increases, provided by an embodiment of the present invention.

[0129] As startup continues, the output voltage V o Start increasing smoothly. There will be four operation modes, such as Figure 6 By limiting iLr to the symmetrical current band, the trajectory is also uniquely determined, consisting of four partial circles, as shown in Figure 6 As the output voltage increases, the current limit band gradually decreases to the full load steady state current. There is no current pressure during startup, V o Build smoothly and quickly.

[0130] In this embodiment, the embodiment of the present invention provides a startup control method for an LLC converter, and its beneficial effects are: the present invention can obtain the resonant frequency and oscillation frequency of the LLC converter; determine the center angle corresponding to the LLC converter according to the resonant frequency; use the center angle and the oscillation frequency to calculate the startup frequency of the LLC converter, and control the startup of the LLC converter according to the startup frequency. In the above manner, the startup frequency required for the LLC converter to start can be accurately calculated, thereby avoiding the generation of current and voltage stress in the resonant cavity, allowing the LLC converter to start more stably, and making the output voltage of the LLC converter more stable.

[0131] The embodiment of the present invention also provides a startup control device for an LLC converter, see Figure 7 , shows a structural schematic diagram of a startup control device for an LLC converter provided by an embodiment of the present invention.

[0132] Wherein, as an example, the startup control device of the LLC converter may include:

[0133] A frequency acquisition module 710 is used to acquire the resonant frequency and oscillation frequency of the LLC converter;

[0134] A center angle determination module 720 is used to determine a center angle corresponding to the LLC converter according to the resonant frequency, wherein the center angle is a center angle corresponding to an arc of a state trajectory of the LLC converter;

[0135] The starting module 730 is used to calculate the starting frequency of the LLC converter by using the central angle and the oscillation frequency, and control the starting of the LLC converter according to the starting frequency.

[0136] Optionally, determining the center angle corresponding to the LLC converter according to the resonant frequency includes:

[0137] Extracting the switch on time from a state trajectory of the LLC converter, wherein the state trajectory is constructed based on the resonant inductor current and the resonant capacitor voltage of the LLC converter before the LLC converter is started;

[0138] The switch on time and the resonant frequency are used to calculate the center angle corresponding to the LLC converter.

[0139] Optionally, the operation of constructing the state trajectory of the LLC converter includes:

[0140] Before the LLC converter is started, the resonant inductor current and the resonant capacitor voltage are obtained and normalized to obtain a normalized current and a normalized voltage;

[0141] After constructing a state plane with the normalized current as the abscissa and the normalized voltage as the ordinate, the normalized current and the normalized voltage are used to construct a trajectory equation of the LLC converter;

[0142] The trajectory of the trajectory equation in the state plane is determined to obtain the state trajectory.

[0143] Optionally, the calculating the center angle corresponding to the LLC converter by using the switch on time and the resonant frequency includes:

[0144] According to the following formula, calculate the center angle corresponding to the LLC converter:

[0145]

[0146] Where T1 is the on-time of LLC converter switch Q1, T2 is the on-time of LLC converter switch Q2, ω0 is the resonant frequency, and the center angle of the LLC converter is

[0147] The resonant frequency ω0 is expressed as follows:

[0148]

[0149] L r is the resonant inductor, C r is the resonant capacitor.

[0150] Optionally, the calculating the starting frequency of the LLC converter by using the central angle and the oscillation frequency includes:

[0151] The starting frequency of the LLC converter is calculated according to the following formula:

[0152]

[0153] In the above formula, f s_ini is the starting frequency, ω 0，m is the oscillation frequency, is the center angle corresponding to the LLC converter;

[0154] The oscillation frequency is expressed as follows:

[0155]

[0156] Among them, L r is the resonant inductor, C r,age is the capacitance value of the resonant capacitor after aging.

[0157] Optionally, the operation of monitoring the capacitance value of the resonant capacitor after aging includes:

[0158] When the LLC converter is shut down and the LLC converter resonant cavity forms a discharge loop, the digital controller is called to sample the resonant current zero-crossing period T cm , and passes through the zero period T cm Calculate the capacitance value of the resonant capacitor after aging.

[0159] Those skilled in the art can clearly understand that, for the sake of convenience and brevity of description, the specific working process of the device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0160] Furthermore, an embodiment of the present application also provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the startup control method of the LLC converter as described in the above embodiment is implemented.

[0161] Furthermore, an embodiment of the present application also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer-executable program, and the computer-executable program is used to enable a computer to execute the startup control method of the LLC converter as described in the above embodiment.

[0162] It should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. When an element such as a layer, region or substrate is referred to as being "on" or "above" another element, it can be directly on the other element, or there can also be an intermediate element. On the contrary, when an element is referred to as "directly on" or "above" another element, there is no intermediate element. It should also be understood that when an element is referred to as being "under" or "below" another element, it can be directly under or below the other element, or there can also be an intermediate element. On the contrary, when an element is referred to as being "directly under" or "below" another element, there is no intermediate element. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0163] Those skilled in the art will appreciate that the embodiments of the present application may also provide computer program products. Therefore, the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program codes.

[0164] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), apparatuses, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0165] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0166] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0167] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A startup control method for an LLC converter, characterized in that: The method comprises: Obtain the resonant frequency and oscillation frequency of the LLC converter; Determine a center angle corresponding to the LLC converter according to the resonant frequency, wherein the center angle is a center angle corresponding to an arc of a state trajectory of the LLC converter; The starting frequency of the LLC converter is calculated using the central angle and the oscillation frequency, and the LLC converter is controlled to start according to the starting frequency.

2. The LLC converter startup control method according to claim 1, characterized in that: The determining the center angle corresponding to the LLC converter according to the resonant frequency includes: Extracting the switch on time from a state trajectory of the LLC converter, wherein the state trajectory is constructed based on the resonant inductor current and the resonant capacitor voltage of the LLC converter before the LLC converter is started; The switch on time and the resonant frequency are used to calculate the center angle corresponding to the LLC converter.

3. The startup control method of LLC converter according to claim 2, characterized in that: The operation of constructing the state trajectory of the LLC converter includes: Before the LLC converter is started, the resonant inductor current and the resonant capacitor voltage are obtained and normalized to obtain a normalized current and a normalized voltage; After constructing a state plane with the normalized current as the abscissa and the normalized voltage as the ordinate, the normalized current and the normalized voltage are used to construct a trajectory equation of the LLC converter; The trajectory of the trajectory equation in the state plane is determined to obtain the state trajectory.

4. The LLC converter startup control method according to claim 2, characterized in that: The calculating the center angle corresponding to the LLC converter by using the switch on time and the resonant frequency includes: According to the following formula, calculate the center angle corresponding to the LLC converter: Where T1 is the on-time of LLC converter switch Q1, T2 is the on-time of LLC converter switch Q2, ω0 is the resonant frequency, and the center angle of the LLC converter is The resonant frequency ω0 is expressed as follows: L r is the resonant inductor, C r is the resonant capacitor.

5. The LLC converter startup control method according to claim 1, characterized in that: The step of calculating the starting frequency of the LLC converter by using the central angle and the oscillation frequency includes: The starting frequency of the LLC converter is calculated according to the following formula: In the above formula, f s_ini is the starting frequency, ω 0，m is the oscillation frequency, is the center angle corresponding to the LLC converter; The oscillation frequency is expressed as follows: Among them, L r is the resonant inductor, C r,age is the capacitance value of the resonant capacitor after aging.

6. The LLC converter startup control method according to claim 5, characterized in that: The operation of monitoring the capacitance value of the resonant capacitor after aging includes: When the LLC converter is shut down and the LLC converter resonant cavity forms a discharge loop, the digital controller is called to sample the resonant current zero-crossing period T cm , and passes through the zero period T cm Calculate the capacitance value of the resonant capacitor after aging.

7. A startup control device for an LLC converter, characterized in that: The device comprises: A frequency acquisition module is used to obtain the resonant frequency and oscillation frequency of the LLC converter; A module for determining a center angle of a circle, used to determine a center angle of a circle corresponding to the LLC converter according to the resonant frequency, wherein the center angle of a circle is a center angle of a circular arc corresponding to a state trajectory of the LLC converter; A starting module is used to calculate a starting frequency of the LLC converter by using the central angle and the oscillation frequency, and control the starting of the LLC converter according to the starting frequency.

8. The startup control device of LLC converter according to claim 7, characterized in that: The determining the center angle corresponding to the LLC converter according to the resonant frequency includes: Extracting the switch on time from a state trajectory of the LLC converter, wherein the state trajectory is constructed based on the resonant inductor current and the resonant capacitor voltage of the LLC converter before the LLC converter is started; The switch on time and the resonant frequency are used to calculate the center angle corresponding to the LLC converter.

9. An electronic device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the startup control method of the LLC converter as described in any one of claims 1 to 6 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer-executable program, and the computer-executable program is used to enable a computer to execute the startup control method of the LLC converter according to any one of claims 1 to 6.

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