A control method and device applied to an LLC resonant circuit

Abstract

The application discloses a control method and device applied to an LLC resonant circuit, responds to a circuit gain adjustment request, acquires a current operation state of the LLC resonant circuit, determines a corresponding action instruction based on the circuit gain adjustment request and the current operation state, switches on-off states of a first switch group, a second switch group and a third switch according to the action instruction, so that the LLC resonant circuit can be switched to different circuit modes according to different gain requirements, and the problem that when the output voltage variation range of a power module is large, the switching frequency of a three-phase LLC resonant circuit is changed greatly, the resonant current waveform is poor, and the stability of circuit operation is improved is avoided.

Description

Technical Field

[0001] This invention relates to the field of control technology for LLC resonant circuits, and more particularly to a control method and apparatus for LLC resonant circuits. Background Technology

[0002] With the country's vigorous development of the new energy vehicle industry, the number of electric vehicles is growing rapidly, and people's demand for electric vehicles is increasing. However, under the current battery technology, problems such as long charging time, high cost of charging piles, and high failure rate restrict the rapid development of electric vehicles. As the core component of charging piles, the charging module restricts the charging time of electric vehicles, the cost of charging piles, and their reliability. Under the current charging module technology, the output constant power range is relatively narrow, which prevents some electric vehicle models from charging at the maximum power point, thus limiting the charging time. Many manufacturers have tried to widen the constant power output range of charging modules by adding power devices, but this not only greatly increases the cost but also results in low efficiency and low reliability in the low-voltage constant power range.

[0003] In the existing technology, the charging pile module is mainly composed of a three-phase LLC resonant circuit structure. It has high gain linearity and high system efficiency near the amplitude frequency, and can output constant power in the range near the resonance point.

[0004] However, in the aforementioned prior art, when the output voltage of the power module varies within a large range, the switching frequency of the three-phase LLC resonant circuit will vary significantly, resulting in a poor resonant current waveform and reducing the stability of the circuit operation. Summary of the Invention

[0005] This invention provides a control method and apparatus for LLC resonant circuits, which solves the technical problem that when the output voltage of the power module varies greatly, the switching frequency of the LLC resonant circuit changes significantly, resulting in poor resonant current waveform and reduced circuit stability.

[0006] This invention provides a control method for an LLC resonant circuit. The LLC resonant circuit is equipped with a first switch group, a second switch group, and a third switch. The primary windings of a first isolation transformer, a second isolation transformer, and a third isolation transformer are connected through the first switch group. The secondary winding of the first isolation transformer is connected to two sets of power switching transistors through the third switch. The primary windings of the first, second, and third isolation transformers are respectively connected to the two sets of power switching transistors through the second switch group. The method includes:

[0007] In response to a circuit gain adjustment request, the current operating state of the LLC resonant circuit is obtained;

[0008] Based on the circuit gain adjustment request and the current operating state, determine the corresponding action command;

[0009] The on / off states of the first switch group, the second switch group, and the third switch are switched according to the action command.

[0010] Optionally, the step of responding to the gain adjustment request of the circuit and obtaining the current operating state of the LLC resonant circuit includes:

[0011] In response to a circuit gain adjustment request, the current on / off states of the first switch group, the second switch group, and the third switch of the LLC resonant circuit are obtained;

[0012] If the first switch group is closed and the third switch is open, then the current operating state is determined to be high voltage mode.

[0013] If the first switch group is open and the third switch is open, then the current operating state is determined to be low voltage mode.

[0014] If the first switch group is open and the third switch is closed, then the current operating state is determined to be low current mode.

[0015] Optionally, the second switch group includes a first gain switch, a second gain switch, and a third gain switch. When the circuit gain adjustment request is to output a high voltage, the step of determining the corresponding action command based on the circuit gain adjustment request and the current operating state includes:

[0016] If the current operating state is low voltage mode, then the action command is determined to be closing the first switch group, opening the first gain switch, the second gain switch and the third gain switch;

[0017] If the current operating state is low current mode, the action command is to close the first switch group, open the first gain switch and the third switch.

[0018] Optionally, when the circuit gain adjustment request is to output a low voltage, the step of determining the corresponding action command based on the circuit gain adjustment request and the current operating state includes:

[0019] If the current operating state is high voltage mode, then the action command is to disconnect the first switch group and close the second switch group;

[0020] If the current operating state is low current mode, then close the second gain switch and the third gain switch, and open the third switch.

[0021] Optionally, when the circuit gain adjustment request is to output low current, the step of determining the corresponding action command based on the circuit gain adjustment request and the current operating state includes:

[0022] If the current operating state is high voltage mode, then the action command is to disconnect the first switch group, close the first gain switch and the third switch;

[0023] If the current operating state is low voltage mode, the action command is to disconnect the second gain switch and the third gain switch, and close the third switch.

[0024] A second aspect of the present invention provides a control device for an LLC resonant circuit, wherein the LLC resonant circuit is provided with a first switch group, a second switch group, and a third switch. The primary windings of a first isolation transformer, a second isolation transformer, and a third isolation transformer are connected through the first switch group. The secondary winding of the first isolation transformer is connected to two sets of power switching transistors through the third switch. The primary windings of the first isolation transformer, the second isolation transformer, and the third isolation transformer are respectively connected to two sets of power switching transistors through the second switch group. The device includes:

[0025] The operating status acquisition module is used to respond to circuit gain adjustment requests and acquire the current operating status of the LLC resonant circuit;

[0026] The data processing module is used to determine the corresponding action command based on the circuit gain adjustment request and the current operating state;

[0027] The execution module is used to switch the on / off states of the first switch group, the second switch group, and the third switch according to the action command.

[0028] Optionally, the running status acquisition module includes:

[0029] The switch status acquisition submodule is used to respond to circuit gain adjustment requests and obtain the current on / off status of the first switch group, the second switch group, and the third switch of the LLC resonant circuit.

[0030] The first state determination submodule is used to determine that the current operating state is high voltage mode if the on / off state of the first switch group is closed and the on / off state of the third switch is open.

[0031] The second state determination submodule is used to determine that the current operating state is low voltage mode if the on / off state of the first switch group is open and the on / off state of the third switch is open.

[0032] The third state determination submodule is used to determine that the current operating state is low current mode if the on / off state of the first switch group is open and the on / off state of the third switch is closed.

[0033] Optionally, the second switch group includes a first gain switch, a second gain switch, and a third gain switch. When the circuit gain adjustment request is to output a high voltage, the data processing module includes:

[0034] The first state execution submodule is used to determine the action command as closing the first switch group, opening the first gain switch, the second gain switch and the third gain switch if the current operating state is low voltage mode.

[0035] The second state execution submodule is used to, if the current operating state is low current mode, then the action command is to close the first switch group, open the first gain switch and the third switch.

[0036] Optionally, when the circuit gain adjustment request is to output a low voltage, the data processing module includes:

[0037] The third state execution submodule is used to, if the current operating state is high voltage mode, then the action command is to disconnect the first switch group and close the second switch group;

[0038] The fourth state execution submodule is used to close the second gain switch and the third gain switch and open the third switch if the current operating state is low current mode.

[0039] Optionally, when the circuit gain adjustment request is for low output current, the data processing module includes:

[0040] The fifth state execution submodule is used to, if the current operating state is high voltage mode, then the action command is to disconnect the first switch group, close the first gain switch and the third switch;

[0041] The sixth state execution submodule is used to, if the current operating state is low voltage mode, then the action command is to disconnect the second gain switch and the third gain switch, and close the third switch.

[0042] As can be seen from the above technical solutions, the present invention has the following advantages:

[0043] When this invention receives a circuit gain adjustment request from a technician, it acquires the current operating state of the LLC resonant circuit, analyzes the circuit gain adjustment request, determines the operating state that the LLC resonant circuit needs to switch to, and determines the action instructions to be executed by the first switch group, the second switch group, and the third switch based on the current operating state and the required switching operating state. It then switches the on / off states of the first switch group, the second switch group, and the third switch according to the action instructions. This allows the LLC resonant circuit to adjust its circuit gain according to changes in the output voltage, thereby solving the technical problem in the prior art where a large range of power module output voltage changes leads to large variations in the switching frequency of the LLC resonant circuit, resulting in poor resonant current waveforms and reduced circuit stability. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a flowchart illustrating the steps of a control method applied to an LLC resonant circuit according to Embodiment 1 of the present invention.

[0046] Figure 2 This is a flowchart illustrating the steps of a control method applied to an LLC resonant circuit according to Embodiment 2 of the present invention.

[0047] Figure 3 This is a circuit diagram of the high-voltage mode of the LLC resonant circuit provided in Embodiment 2 of the present invention;

[0048] Figure 4 This is a circuit schematic diagram of the low-voltage mode of the LLC resonant circuit provided in Embodiment 2 of the present invention;

[0049] Figure 5 This is a circuit schematic diagram of the low-current mode of the LLC resonant circuit provided in Embodiment 2 of the present invention;

[0050] Figure 6 This is a structural block diagram of a control device applied to an LLC resonant circuit, provided in Embodiment 3 of the present invention. Detailed Implementation

[0051] This invention provides a control method and apparatus for LLC resonant circuits, which addresses the technical problem that in the prior art, when the output voltage of the power module varies within a large range, the switching frequency of the three-phase LLC resonant circuit changes significantly, resulting in poor resonant current waveform and reduced circuit stability.

[0052] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0053] Please see Figure 1 , Figure 1 The flowchart illustrates the steps of a control method for an LLC resonant circuit provided in Embodiment 1 of the present invention.

[0054] This invention provides a control method for an LLC resonant circuit. The LLC resonant circuit includes a first switch group, a second switch group, and a third switch. The primary windings of the first, second, and third isolation transformers are connected via the first switch group. The secondary winding of the first isolation transformer is connected to two sets of power switching transistors via the third switch. The primary windings of the first, second, and third isolation transformers are respectively connected to two sets of power switching transistors via the second switch group. The method includes:

[0055] Step 101: Respond to the circuit gain adjustment request and obtain the current operating status of the LLC resonant circuit.

[0056] A circuit gain adjustment request refers to a control request issued by an engineer to achieve different gain requirements at the input and output of an LLC resonant circuit. For example, when the LLC resonant circuit needs to output a high voltage, a low voltage, or a low current.

[0057] The current operating state refers to the control mode in which the input and output gains of the LLC resonant circuit are currently located. For example, high-voltage mode, low-voltage mode, and low-current mode.

[0058] In this embodiment of the invention, when a circuit gain adjustment is received from a person skilled in the art, the control mode of the LLC resonant circuit is obtained by reading the on / off states of the first switch group, the second switch group, and the third switch through the operation platform.

[0059] Step 102: Determine the corresponding action command based on the circuit gain adjustment request and the current operating status.

[0060] Action commands refer to the switching of the open and closed states of the first, second, and third switch groups in an LLC resonant circuit. For example, closing circuit breakers, disconnectors, air switches, knife switches, and relays, and opening circuit breakers, disconnectors, air switches, knife switches, and relays.

[0061] In this embodiment of the invention, after obtaining the current control mode of the LLC resonant circuit and the control mode that the LLC resonant circuit needs to switch, the action instructions that the first switch group, the second switch group, and the third switch need to execute are adjusted according to the on / off state of the current LLC resonant circuit's first switch group, the second switch group, and the third switch and the control mode that the LLC resonant circuit needs to switch.

[0062] Step 103: Switch the on / off state of the first switch group, the second switch group, and the third switch according to the action command.

[0063] In this embodiment of the invention, after obtaining the action command, the first switch group, the second switch group, and the third switch are controlled to close or open according to the action command.

[0064] In this embodiment of the invention, when a request for LLC resonant circuit gain adjustment is received from a technician, the current control mode of the LLC resonant circuit is obtained by reading the on / off states of the first, second, and third switch groups through the operating platform. Based on the current control mode of the LLC resonant circuit and the required switching control mode, the action commands to be executed by the first, second, and third switch groups are determined, and then the first, second, and third switch groups are controlled to close or open according to the action commands. This solves the technical problem that when using a traditional LLC resonant circuit, the switching frequency of the LLC resonant circuit changes significantly when the output voltage of the power module varies within a large range, resulting in poor resonant current waveforms and reduced circuit stability. It achieves wide gain adjustment of the LLC resonant circuit and improves the stability of circuit operation.

[0065] Please see Figure 2 , Figure 2 This is a flowchart illustrating the steps of a control method applied to an LLC resonant circuit, as provided in Embodiment 2 of the present invention.

[0066] This invention provides a control method for an LLC resonant circuit. The LLC resonant circuit includes a first switch group, a second switch group, and a third switch. The primary windings of the first, second, and third isolation transformers are connected via the first switch group. The secondary winding of the first isolation transformer is connected to two sets of power switching transistors via the third switch. The primary windings of the first, second, and third isolation transformers are respectively connected to two sets of power switching transistors via the second switch group. The method includes:

[0067] Step 201: Respond to the circuit gain adjustment request and obtain the current on / off state of the first switch group, the second switch group, and the third switch of the LLC resonant circuit.

[0068] The first switch group, the second switch group, and the third switch refer to relays or intelligent circuit breakers, etc.

[0069] On / off state refers to whether the switch in the circuit is closed or open.

[0070] In this embodiment of the invention, when a request for circuit gain adjustment is received from a technician, the on / off status of the first switch group, the second switch group, and the third switch is obtained through the operation platform.

[0071] Step 202: If the first switch group is closed and the third switch is open, then the current operating state is determined to be high voltage mode.

[0072] Please see Figure 3 The second switch group includes a first gain switch S21, a second gain switch S22, and a third gain switch S23. The first switch group includes S11, S12, and S13. The third switch S3 is open, and the first switch group is closed. In the second switch group, the first gain switch S21, the second gain switch S22, and the third gain switch S23 are all open. At this time, all the switches in the LLC resonant circuit are used to adjust the output voltage, resulting in a high circuit gain. Therefore, the LLC resonant circuit operates in high-voltage mode at this time.

[0073] High-voltage mode refers to the electrical connection structure when the LLC resonant circuit outputs a high voltage.

[0074] In this embodiment of the invention, when the on / off state of the first switch group is closed and the on / off state of the third switch is open, the current operating state of the LLC resonant circuit is determined to be high voltage mode.

[0075] Step 203: If the on / off state of the first switch group is open and the on / off state of the third switch is open, then the current operating state is determined to be low voltage mode.

[0076] Please see Figure 4 The first switch group is closed, the first gain switch S21, the second gain switch S22 and the third gain switch S23 are all closed, and the third switch S3 is open. At this time, the resonant cavity of the LLC resonant circuit is switched from the star connection of the traditional LLC resonant circuit to the delta connection. At the same switching frequency, the gain of the LLC resonant circuit can be reduced. Therefore, the operating state of the LLC resonant circuit is low voltage mode at this time.

[0077] Low-voltage mode refers to the electrical connection structure of an LLC resonant circuit when the output voltage is low.

[0078] In this embodiment of the invention, when the on / off state of the first switch group is on / off and the on / off state of the third switch is off, it is determined that the current operating state of the LLC resonant circuit is low voltage mode.

[0079] Step 204: If the first switch group is open and the third switch is closed, then the current operating state is determined to be low current mode.

[0080] Please see Figure 5 The first switch group is open, the first gain switch S21 is closed, the second gain switch S22 and the third gain switch S23 are both open, and the third switch S3 is open. At this time, only the switches Q1p, Q2p, Q4p, Q5p, Q1s, Q2s, Q4s and Q5s are working in the LLC resonant circuit, which reduces the output current of the LLC resonant circuit. Therefore, the LLC resonant circuit is in low current mode at this time.

[0081] In this embodiment of the invention, when the first switch group is open and the third switch is closed, the current operating state of the LLC resonant circuit is determined to be low current mode.

[0082] Step 205: Determine the corresponding action command based on the circuit gain adjustment request and the current operating status.

[0083] Furthermore, step 205 may include the following sub-steps:

[0084] S11. The second switch group includes a first gain switch, a second gain switch, and a third gain switch. When the circuit gain adjustment request is to output a high voltage, the steps for determining the corresponding action command based on the circuit gain adjustment request and the current operating state include:

[0085] If the current operating state is low voltage mode, the action command is determined to be to close the first switch group and open the first gain switch, the second gain switch and the third gain switch;

[0086] If the current operating state is low current mode, the action command is to close the first switch group, open the first gain switch and the third switch.

[0087] In this embodiment of the invention, when the circuit gain adjustment request is to output a high voltage, the LLC resonant circuit needs to be switched to the high voltage mode. If the current operating state is the low voltage mode, the action command is determined to close the first switch group and open the first gain switch, the second gain switch and the third gain switch. If the current operating state is the low current mode, the action command is determined to close the first switch group and open the first gain switch and the third switch.

[0088] S12. When the circuit gain adjustment request is a low output voltage, the steps for determining the corresponding action command based on the circuit gain adjustment request and the current operating state include:

[0089] If the current operating state is high voltage mode, the action command is to open the first switch group and close the second switch group;

[0090] If the current operating state is low current mode, then close the second gain switch and the third gain switch, and open the third switch.

[0091] In this embodiment of the invention, when the circuit gain adjustment request is to output a low voltage, the LLC resonant circuit needs to be switched to the low voltage mode. If the current operating state is the high voltage mode, the action command is determined to disconnect the first switch group, close the first gain switch, the second gain switch and the third gain switch. If the current operating state is the low current mode, the action command is determined to close the second gain switch and the third gain switch and disconnect the third switch.

[0092] S13. When the circuit gain adjustment request is to output low current, the steps for determining the corresponding action command based on the circuit gain adjustment request and the current operating state include:

[0093] If the current operating state is high voltage mode, the action command is to disconnect the first switch group, close the first gain switch and the third switch;

[0094] If the current operating state is low voltage mode, the action command is to disconnect the second gain switch and the third gain switch, and close the third switch.

[0095] In this embodiment of the invention, when the circuit gain request is to output low current, the LLC resonant circuit needs to be switched to low current mode. If the current operating state is high voltage mode, the action command is determined to disconnect the first switch group and close the first gain switch and the third switch. If the current operating state is low voltage mode, the action command is determined to disconnect the second gain switch and the third gain switch and close the third switch.

[0096] In this embodiment of the invention, after obtaining the current operating state and circuit gain request of the LLC resonant circuit, the required operating mode of the LLC resonant circuit is determined according to the circuit gain request. If the LLC resonant circuit switches from a low-voltage mode to a high-voltage mode, the action command is determined to close the first switch group and open the first gain switch, the second gain switch, and the third gain switch. If the LLC resonant circuit switches from a low-current mode to a high-voltage mode, the action command is determined to close the first switch group and open the first gain switch and the third switch. If the LLC resonant circuit switches from a high-voltage mode to a low-voltage mode, then... The action command is determined as follows: disconnect the first switch group, close the first gain switch, the second gain switch, and the third gain switch. If the LLC resonant circuit switches from low current mode to low voltage mode, the action command is determined as follows: close the second gain switch and the third gain switch, and disconnect the third switch. If the LLC resonant circuit switches from high voltage mode to low current mode, the action command is determined as follows: disconnect the first switch group, close the first gain switch and the third switch. If the LLC resonant circuit switches from low voltage mode to low current mode, the action command is determined as follows: disconnect the second gain switch and the third gain switch, and close the third switch.

[0097] Step 206: Switch the on / off state of the first switch group, the second switch group, and the third switch according to the action command.

[0098] In this embodiment of the invention, after obtaining the action command, the first switch group, the first gain switch, the second gain switch and the third switch are controlled to close or open according to the action command.

[0099] In this embodiment of the invention, when a gain adjustment request for the LLC resonant circuit is received from a technician, the request is analyzed to determine the control mode that the LLC resonant circuit needs to switch to. The on / off states of the first, second, and third switch groups are obtained through the operation display interface to determine the current control mode of the LLC resonant circuit. Based on the current control mode and the required switching mode, the action commands to be executed by the first, second, and third switch groups are determined. Then, the first, second, and third switch groups are controlled to close or open according to the action commands. This solves the technical problem that when the output voltage of the power module varies widely, the switching frequency of the LLC resonant circuit changes significantly, resulting in a poor resonant current waveform and reduced circuit stability. It achieves wide gain adjustment of the LLC resonant circuit and improves the stability of circuit operation.

[0100] Please see Figure 6 , Figure 6 This is a structural block diagram of a control device applied to an LLC resonant circuit, provided in Embodiment 3 of the present invention.

[0101] This invention provides a control device for an LLC resonant circuit. The LLC resonant circuit includes a first switch group, a second switch group, and a third switch. The primary windings of the first, second, and third isolation transformers are connected via the first switch group. The secondary winding of the first isolation transformer is connected to two sets of power switching transistors via the third switch. The primary windings of the first, second, and third isolation transformers are respectively connected to two sets of power switching transistors via the second switch group. The device includes:

[0102] The operating status acquisition module 601 is used to respond to circuit gain adjustment requests and acquire the current operating status of the LLC resonant circuit;

[0103] Data processing module 602 is used to determine the corresponding action command based on the circuit gain adjustment request and the current operating status;

[0104] The execution module 603 is used to switch the on / off states of the first switch group, the second switch group, and the third switch according to the action command.

[0105] Furthermore, the operation status acquisition module 601 includes:

[0106] The switch status acquisition submodule is used to respond to circuit gain adjustment requests and obtain the current on / off status of the first switch group, the second switch group, and the third switch of the LLC resonant circuit.

[0107] The first state determination submodule is used to determine that the current operating state is high voltage mode if the on / off state of the first switch group is closed and the on / off state of the third switch is open.

[0108] The second state determination submodule is used to determine that the current operating state is low voltage mode if the on / off state of the first switch group is open and the on / off state of the third switch is open.

[0109] The third state determination submodule is used to determine that the current operating state is low current mode if the on / off state of the first switch group is open and the on / off state of the third switch is closed.

[0110] Furthermore, the second switch group includes a first gain switch, a second gain switch, and a third gain switch. When the circuit gain adjustment request is to output a high voltage, the data processing module 602 includes:

[0111] The first state execution submodule is used to determine the action command as closing the first switch group, opening the first gain switch, the second gain switch and the third gain switch if the current operating state is low voltage mode.

[0112] The second state execution submodule is used to perform the action command of closing the first switch group, opening the first gain switch and the third switch if the current operating state is low current mode.

[0113] Furthermore, when the circuit gain adjustment request is for a low output voltage, the data processing module 602 also includes:

[0114] The third state execution submodule is used to disconnect the first switch group and close the second switch group if the current operating state is high voltage mode.

[0115] The fourth state execution submodule is used to close the second and third gain switches and open the third switch if the current operating state is low current mode.

[0116] Furthermore, when the circuit gain adjustment request is for low output current, the data processing module 602 also includes:

[0117] The fifth state execution submodule is used to perform the following actions if the current operating state is high voltage mode: disconnect the first switch group, close the first gain switch and the third switch.

[0118] The sixth state execution submodule is used to disconnect the second and third gain switches and close the third switch if the current operating state is low voltage mode.

[0119] In this embodiment, when the operating status acquisition module receives a circuit gain adjustment request, it acquires the current operating status of the LLC resonant circuit. Then, the data processing module analyzes the request to determine the required control mode for the LLC resonant circuit. Based on the current control mode and the required switching mode, it determines the action commands to be executed for the first, second, and third switch groups. The execution module then controls the first, second, and third switch groups to close or open according to the action commands. This solves the technical problem that when the output voltage varies significantly, the switching frequency of the LLC resonant circuit changes greatly, resulting in a poor resonant current waveform and reduced circuit stability. It achieves wide gain adjustment for the LLC resonant circuit and improves its operational stability.

[0120] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and unit can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0122] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0123] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method applied to LLC resonant circuits, characterized in that, The LLC resonant circuit is provided with a first switch group, a second switch group, and a third switch. The primary windings of the first isolation transformer, the second isolation transformer, and the third isolation transformer are connected through the first switch group. The secondary winding of the first isolation transformer is connected to two sets of power switching transistors through the third switch. The primary windings of the first isolation transformer, the second isolation transformer, and the third isolation transformer are respectively connected to two sets of power switching transistors through the second switch group. The method includes: In response to a circuit gain adjustment request, the current operating state of the LLC resonant circuit is obtained; Based on the circuit gain adjustment request and the current operating state, determine the corresponding action command; The on / off states of the first switch group, the second switch group, and the third switch are switched according to the action command.

2. The control method applied to LLC resonant circuits according to claim 1, characterized in that, The step of responding to the gain adjustment request of the circuit and obtaining the current operating state of the LLC resonant circuit includes: In response to a circuit gain adjustment request, the current on / off states of the first switch group, the second switch group, and the third switch of the LLC resonant circuit are obtained; If the first switch group is closed and the third switch is open, then the current operating state is determined to be high voltage mode. If the first switch group is open and the third switch is open, then the current operating state is determined to be low voltage mode. If the first switch group is open and the third switch is closed, then the current operating state is determined to be low current mode.

3. The control method applied to LLC resonant circuits according to claim 2, characterized in that, The second switch group includes a first gain switch, a second gain switch, and a third gain switch. When the circuit gain adjustment request is to output a high voltage, the step of determining the corresponding action command based on the circuit gain adjustment request and the current operating state includes: If the current operating state is low voltage mode, then the action command is determined to be closing the first switch group, opening the first gain switch, the second gain switch and the third gain switch; If the current operating state is low current mode, the action command is to close the first switch group, open the first gain switch and the third switch.

4. The control method applied to LLC resonant circuits according to claim 3, characterized in that, When the circuit gain adjustment request is to output a low voltage, the step of determining the corresponding action command based on the circuit gain adjustment request and the current operating state includes: If the current operating state is high voltage mode, then the action command is to disconnect the first switch group and close the second switch group; If the current operating state is low current mode, then close the second gain switch and the third gain switch, and open the third switch.

5. The control method applied to LLC resonant circuits according to claim 3, characterized in that, When the circuit gain adjustment request is to output low current, the step of determining the corresponding action command based on the circuit gain adjustment request and the current operating state includes: If the current operating state is high voltage mode, then the action command is to disconnect the first switch group, close the first gain switch and the third switch; If the current operating state is low voltage mode, the action command is to disconnect the second gain switch and the third gain switch, and close the third switch.

6. A control device applied to an LLC resonant circuit, characterized in that, The LLC resonant circuit is provided with a first switch group, a second switch group, and a third switch. The primary windings of the first isolation transformer, the second isolation transformer, and the third isolation transformer are connected through the first switch group. The secondary winding of the first isolation transformer is connected to two sets of power switching transistors through the third switch. The primary windings of the first isolation transformer, the second isolation transformer, and the third isolation transformer are respectively connected to two sets of power switching transistors through the second switch group. The device includes: The operating status acquisition module is used to respond to circuit gain adjustment requests and acquire the current operating status of the LLC resonant circuit; The data processing module is used to determine the corresponding action command based on the circuit gain adjustment request and the current operating state; The execution module is used to switch the on / off states of the first switch group, the second switch group, and the third switch according to the action command.

7. The control device for an LLC resonant circuit according to claim 6, characterized in that, The operation status acquisition module includes: The switch status acquisition submodule is used to respond to circuit gain adjustment requests and obtain the current on / off status of the first switch group, the second switch group, and the third switch of the LLC resonant circuit. The first state determination submodule is used to determine that the current operating state is high voltage mode if the on / off state of the first switch group is closed and the on / off state of the third switch is open. The second state determination submodule is used to determine that the current operating state is low voltage mode if the on / off state of the first switch group is open and the on / off state of the third switch is open. The third state determination submodule is used to determine that the current operating state is low current mode if the on / off state of the first switch group is open and the on / off state of the third switch is closed.

8. The control device for an LLC resonant circuit according to claim 7, characterized in that, The second switch group includes a first gain switch, a second gain switch, and a third gain switch. When the circuit gain adjustment request is to output a high voltage, the data processing module includes: The first state execution submodule is used to determine the action command as closing the first switch group, opening the first gain switch, the second gain switch and the third gain switch if the current operating state is low voltage mode. The second state execution submodule is used to, if the current operating state is low current mode, then the action command is to close the first switch group, open the first gain switch and the third switch.

9. The control device for an LLC resonant circuit according to claim 8, characterized in that, When the circuit gain adjustment request is to output a low voltage, the data processing module includes: The third state execution submodule is used to, if the current operating state is high voltage mode, then the action command is to disconnect the first switch group and close the second switch group; The fourth state execution submodule is used to close the second gain switch and the third gain switch and open the third switch if the current operating state is low current mode.

10. The control device applied to an LLC resonant circuit according to claim 8, characterized in that, When the circuit gain adjustment request is to output low current, the data processing module includes: The fifth state execution submodule is used to, if the current operating state is high voltage mode, then the action command is to disconnect the first switch group, close the first gain switch and the third switch; The sixth state execution submodule is used to, if the current operating state is low voltage mode, then the action command is to disconnect the second gain switch and the third gain switch, and close the third switch.

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