Soft switching method and system for charging and discharging of switching power supply

Abstract

The application discloses a switching power supply charging and discharging soft switching method and system, and the method comprises the following steps: judging the current working mode of the switching power supply; in the charging mode and the discharging mode, the drive duty cycle of the primary side bridge switching group is controlled to be a preset first target value; in the charging mode, the drive duty cycle of the secondary side bridge switching group is continuously adjusted to a second target value at a predetermined rate, and the drive duty cycle of the secondary side bridge switching group is controlled to be kept at the second target value; in the discharging mode, the drive duty cycle of the secondary side bridge switching group is continuously adjusted to the first target value at a predetermined rate, and the drive duty cycle of the secondary side bridge switching group is controlled to be kept at the first target value; through the switching method, two sets of different drives are configured for the charging mode and the discharging mode of the switching power supply respectively, so that the working efficiency of the switching power supply in the charging mode and the discharging mode is effectively ensured, the problem of discontinuous working mode switching is solved, and the stability of the switching power supply is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of switching power supply technology, and in particular to a soft switching method and system for charging and discharging a switching power supply based on a bidirectional LLC resonant converter. Background Technology

[0002] Due to its high efficiency and ease of achieving bidirectional energy flow, LLC resonant converters are widely used in bidirectional power supplies. The synchronous rectification of LLC resonant converters differs from conventional synchronous rectification. During forward operation, when the LLC resonant converter operates above the higher of the two resonant points, the secondary current is continuous; when operating at the higher resonant point, the secondary current is in a critical state; and when operating below the higher resonant point, the secondary current is discontinuous. In the continuous state, the secondary-side switch drive can be synchronized with the primary side. In the discontinuous state, the duty cycle of the secondary-side switch must be less than that of the primary side to shut down synchronous rectification before the current reaches zero; otherwise, backflow current will cause the converter to fail.

[0003] Therefore, due to the special characteristics of synchronous rectification in LLC resonant converters, the existing control strategy is to set the secondary duty cycle to a fixed value that is smaller than the primary duty cycle, leaving sufficient margin to ensure that synchronous rectification is turned off in advance when the secondary current is zero.

[0004] However, when operating in reverse discharge mode, the LLC resonant converter degenerates into an LC resonant converter. In this case, the primary side acts as a synchronous rectifier, and the secondary side acts as a resonant generator. In this reverse operating state, to ensure operating efficiency, the primary and secondary drives of the LC resonant converter need to be configured with a fixed duty cycle of approximately 50%.

[0005] In summary, since the drive configuration of the LLC resonant converter differs between forward and reverse operation, the drive configuration must also switch synchronously when switching between charging and discharging. The current switching method is hard switching, which cannot achieve continuous, seamless switching. Forcing continuity leads to back-and-forth drive changes at the critical point of charge / discharge switching, causing system instability. Another approach is to keep the drive unchanged when changing from forward charging mode to reverse operating mode, still using the forward charging mode drive. This approach allows for continuous and seamless switching between charging and discharging; however, since discharging still uses the charging drive, the secondary drive is a fixed value and less than 50%, which is detrimental to improving discharging efficiency. This is because, in discharging mode, the secondary duty cycle should ideally be close to 50% for higher efficiency. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the aforementioned technical problems by providing a switching power supply charging and discharging soft switching method and system based on a bidirectional LLC resonant converter, which can achieve continuous soft switching of charging and discharging states and can also configure different drives for forward charging and reverse operation to ensure working efficiency.

[0007] To achieve the above objectives, this invention discloses a soft-switching method for charging and discharging a switching power supply based on a bidirectional LLC resonant converter. The switching power supply includes an LLC resonant circuit, a primary-side bridge switch group disposed on the primary side of the LLC resonant circuit, and a secondary-side bridge switch group disposed on the secondary side of the LLC resonant circuit. The switching power supply includes a charging mode and a discharging mode. The soft-switching method for charging and discharging the switching power supply includes:

[0008] Determine the current operating mode of the switching power supply;

[0009] In the charging mode and the discharging mode, the drive duty cycle of the primary-side bridge switch group is controlled to a preset first target value;

[0010] In the charging mode, it is determined whether the drive duty cycle of the secondary bridge switch group has reached a preset second target value. The second target value is less than the first target value. If not, the drive duty cycle of the secondary bridge switch group is controlled to be continuously adjusted to the second target value at a predetermined rate, and the drive duty cycle of the secondary bridge switch group is controlled to be maintained at the second target value.

[0011] In the discharge mode, it is determined whether the drive duty cycle of the secondary bridge switch group has reached the first target value. If not, the drive duty cycle of the secondary bridge switch group is controlled to be continuously adjusted to the first target value at a predetermined rate, and the drive duty cycle of the secondary bridge switch group is kept at the first target value.

[0012] Preferably, in the charging mode, the second target value is a variation range, and the different duty cycles within the variation range correspond to the operating frequency of the secondary bridge switch group. Furthermore, the driving duty cycle of the secondary bridge switch group is controlled to dynamically change in accordance with the operating frequency of the secondary bridge switch group within the variation range.

[0013] Preferably, the method for determining the operating mode of the switching power supply includes:

[0014] Determine whether the current is greater than or equal to a first preset current. If yes, the switching power supply is in the charging mode; otherwise, the switching power supply is in the discharging mode.

[0015] Preferably, the method for determining the operating mode of the switching power supply further includes:

[0016] If the current is less than the first preset current, it is determined again whether the current is less than or equal to the second preset current. If the second preset current is less than the first preset current, the switching power supply is in the discharge mode. If not, it is determined that the switching power supply remains in the current working state.

[0017] Preferably, the first target value is 50%, and the range of variation is [35%, 41%].

[0018] The present invention also discloses a soft switching system for charging and discharging of a switching power supply based on a bidirectional LLC resonant converter. The switching power supply includes an LLC resonant circuit, a primary-side bridge switch group disposed on the primary side of the LLC resonant circuit, and a secondary-side bridge switch group disposed on the secondary side of the LLC resonant circuit. The switching power supply includes a charging mode and a discharging mode. The switching system includes a working mode determination module, a charging drive adjustment module, and a discharging drive adjustment module.

[0019] The operating mode determination module is used to determine the current operating mode of the switching power supply;

[0020] The charging drive adjustment module is used to continuously adjust the drive duty cycle of the secondary bridge switch group to a second target value at a predetermined rate in the charging mode, and control the drive duty cycle of the primary bridge switch group to a preset first target value, wherein the second target value is less than the first target value.

[0021] The discharge drive adjustment module is used to continuously adjust the drive duty cycle of the secondary bridge switch group to a second target value at a predetermined rate in the discharge mode, and control the drive duty cycle of the secondary bridge switch group to continuously adjust to the first target value at a predetermined rate, so that the drive duty cycle of the secondary bridge switch group is maintained at the first target value.

[0022] Preferably, in the charging mode, the second target value is a variation range, and the different duty cycles within the variation range correspond to the operating frequency of the secondary bridge switch group. Furthermore, the charging drive adjustment module controls the drive duty cycle of the secondary bridge switch group to dynamically change within the variation range following the operating frequency of the secondary bridge switch group.

[0023] Preferably, the operating mode determination module includes a first determination module and a second determination module. The first determination module is used to determine whether the current current is greater than or equal to a first preset current. If yes, the switching power supply is in the charging mode; if no, the switching power supply is in the discharging mode. The second determination module is used to determine whether the current current is less than or equal to a second preset current when the current current is less than the first preset current. If the second preset current is less than the first preset current, the switching power supply is in the discharging mode; if no, the switching power supply is determined to remain in the current operating state.

[0024] The present invention also discloses another soft-switching system for charging and discharging a switching power supply, comprising:

[0025] One or more processors;

[0026] Memory;

[0027] And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for executing the switching power supply charge / discharge soft switching method based on the bidirectional LLC resonant converter as described above.

[0028] The present invention also discloses a computer-readable storage medium, characterized in that it includes a computer program, which can be executed by a processor to perform the soft switching method for charging and discharging of a switching power supply based on a bidirectional LLC resonant converter as described above.

[0029] Compared with existing technologies, the soft switching method for charging and discharging of the switching power supply of the present invention has the following characteristics: In the discharging mode, the drive duty cycle of both the primary-side bridge switch group and the secondary-side bridge switch group is a fixed first target value; in the charging mode, the drive duty cycle of the primary-side bridge switch group is the first target value, and the secondary-side bridge switch group is a smaller second target value. Moreover, whether switching from the charging mode to the discharging mode or vice versa, the duty cycle is continuously adjusted to achieve the switching purpose. Thus, it can be seen that, through the above switching method, firstly, two different drives are configured for the charging mode and the discharging mode of the switching power supply, thereby effectively ensuring the working efficiency of the switching power supply in the charging mode and the discharging mode. In addition, the soft switching strategy solves the problem of discontinuous switching of working modes and effectively improves the stability of the switching power supply. Attached Figure Description

[0030] Figure 1 This is a flowchart of a soft switching method for charging and discharging a switching power supply according to one embodiment of the present invention.

[0031] Figure 2This is a flowchart of a soft switching method for charging and discharging a switching power supply according to another embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the resonant transformation topology of a switching power supply operating in forward charging mode in an embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram of the resonant transformation topology of a switching power supply operating in reverse discharge mode in an embodiment of the present invention. Detailed Implementation

[0034] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0035] This embodiment discloses a soft-switching method for charging and discharging a switching power supply based on a bidirectional LLC resonant converter, for switching the operating mode of the switching power supply, such as... Figure 3 The switching power supply in this embodiment includes an LLC resonant circuit P0, a primary-side bridge switch group Q1 disposed on the primary side of the LLC resonant circuit, and a secondary-side bridge switch group Q2 disposed on the secondary side of the LLC resonant circuit. The switching power supply includes a charging mode and a discharging mode. In the charging mode, such as... Figure 3 Current flows from the primary side to the secondary side of the LLC resonant circuit. In discharge mode, such as... Figure 4 The current flows from the secondary side to the primary side of the LLC resonant circuit.

[0036] like Figure 1 The soft switching method for charging and discharging of the switching power supply in this embodiment includes the following:

[0037] S1: Determines the current operating mode of the switching power supply;

[0038] S20: In charging mode, control the drive duty cycle of the primary bridge switch group Q1 to a preset first target value, and determine whether the drive duty cycle of the secondary bridge switch group Q2 reaches a preset second target value. If the second target value is less than the first target value, proceed to S21; otherwise, proceed to S22.

[0039] S21: Control the drive duty cycle of the secondary bridge switch group Q2 to be continuously adjusted to the second target value at a predetermined rate;

[0040] S22: Control the drive duty cycle of the secondary bridge switch group Q2 to maintain the second target value;

[0041] S30: In discharge mode, control the drive duty cycle of the primary bridge switch group Q1 to the preset first target value, and determine whether the drive duty cycle of the secondary bridge switch group Q2 has reached the first target value. If not, proceed to S31; if yes, proceed to S32.

[0042] S31: Control the drive duty cycle of the secondary bridge switch group Q2 to be continuously adjusted to the first target value at a predetermined rate;

[0043] S32: Controls the drive duty cycle of the secondary bridge switch group Q2 to maintain the first target value.

[0044] In this embodiment, the first target value is preferably 50%.

[0045] Based on the above switching method, the switching power supply achieves continuous and seamless switching between forward charging mode and reverse discharging mode, solving the problem of discontinuous switching of the switching power supply's working mode. Moreover, two different drives are configured for discharging mode and charging mode respectively, effectively ensuring the working efficiency of the switching power supply in discharging mode and charging mode, thereby achieving stable constant voltage output of the switching power supply.

[0046] With the initial default operating mode set to charging mode, upon power-up, the switching power supply enters charging mode. The initial duty cycle of the secondary bridge switch group Q2 is zero, and then it continuously increases to a second target value according to a predetermined rate. Since the second target value is less than the duty cycle of the primary bridge switch group Q1 (50%), it ensures that the synchronous rectification is shut down before the current reaches zero, preventing backflow and potential damage. When it is determined that the switching power supply is transitioning from charging mode to discharging mode, since the duty cycle of the secondary bridge switch group Q2 is less than 50% at this time, the duty cycle of the secondary bridge switch group Q2 is continuously increased to 50% at a predetermined rate and maintained at 50% operating status. When the switching power supply enters the charging mode from the discharging mode, since the driving duty cycle of the secondary bridge switch group Q2 is 50%, which is greater than the second target value, the driving duty cycle of the secondary bridge switch group Q2 is continuously reduced to the second target value at a predetermined rate, and the driving duty cycle of the secondary bridge switch group Q2 is controlled to remain at the second target value, thereby realizing the soft switching of the working mode.

[0047] Furthermore, in charging mode, the second target value is a variation range, and different duty cycles within this range correspond to the operating frequency of the secondary bridge switch group Q2. For example... Figure 2The method for switching charging modes further includes S23: controlling the drive duty cycle of the secondary bridge switch group Q2 to dynamically change within a range following the operating frequency of the secondary bridge switch group Q2. In this embodiment, the preferred range for the second target value is [35%, 41%]. After the switching power supply enters the charging mode, the drive duty cycle of the secondary bridge switch group Q2 is controlled to be within this range according to the current operating frequency of the switching power supply. Furthermore, as the operating frequency of the switching power supply changes, the drive duty cycle of the secondary bridge switch group Q2 dynamically changes within this range, and the drive duty cycle of the secondary bridge switch group Q2 is positively correlated with the operating frequency of the switching power supply. Since the operating frequency of the switching power supply changes accordingly with the load size during actual operation, and the load change directly affects the current change, the switching method in this embodiment allows the drive duty cycle of the secondary bridge switch group Q2 to follow the loop current change. When the loop current is small, a smaller drive duty cycle is generated, thereby maintaining a small turn-off current and reducing turn-off losses.

[0048] Furthermore, such as Figure 2 Methods for determining the operating mode of a switching power supply include:

[0049] S10: Determine whether the current current is greater than or equal to the first preset current, such as -2A. If yes, the switching power supply is in charging mode; otherwise, the switching power supply is in discharging mode.

[0050] In addition, to avoid frequent adjustments to the switching power supply due to current fluctuations, the method for determining the operating mode of the switching power supply also includes S11: if the current current is less than the first preset current, it is further determined whether the current current is less than or equal to the second preset current. For example, -7A, where the second preset current is less than the first preset current. If yes, the switching power supply is in discharge mode; otherwise, it is determined that the switching power supply remains in its current operating state. In this embodiment, a hysteresis region with a certain width is formed between the first preset current and the second preset current. When the current fluctuates into the hysteresis region, the switching power supply is still considered to be in its current operating mode, and the drive duty cycle strategy is not adjusted. This avoids frequent adjustments to the switching power supply caused by current fluctuations, making the operating performance of the switching power supply more stable.

[0051] In summary, the working process of the soft switching method for charging and discharging of the switching power supply disclosed in the above embodiments is as follows:

[0052] After power-on, it automatically enters the forward charging state, with the circuit current greater than -2A. The primary-side bridge switch group Q1 operates at a fixed first target value (50%), and the secondary-side bridge switch group Q2 continuously adjusts its drive duty cycle from zero to the variation range [35%, 41%] at a predetermined rate. During charging, as the load charging power changes, the operating frequency of the switching power supply changes accordingly in the forward direction. Correspondingly, according to a preset relationship, the drive duty cycle of the secondary-side bridge switch group Q2 changes accordingly within the variation range. When the switching power supply switches to discharge mode, the loop current is less than -7A. Based on the detected current loop current value, it is determined that the switching power supply has entered discharge mode. At this time, since the drive duty cycle of the secondary bridge switch group Q2 is within the variation range [35%, 41%] and less than the first target value (50%), the drive duty cycle of the secondary bridge switch group Q2 is continuously increased to 50% at a predetermined rate and then fixed at 50%. When the switching power supply switches from discharge mode to charging mode, the loop current returns to above -2A. At this time, the drive duty cycle of the secondary bridge switch group Q2 is 50%. The drive duty cycle of the secondary bridge switch group Q2 is then continuously decreased from 50% to within the variation range [35%, 41%] at a predetermined rate. In this way, the switching power supply switches between charging mode and discharge mode.

[0053] It should also be noted that the specific adjustment methods for the drive duty cycle of the primary bridge switch group Q1 and the secondary bridge switch group Q2 in the above embodiments are common technical knowledge in the field and will not be elaborated here. For example, the frequency of the switching transistors can be adjusted by using PWM waves or PFM waves to achieve the purpose of adjusting the drive duty cycle.

[0054] This invention also discloses a soft-switching system for charging and discharging a switching power supply based on a bidirectional LLC resonant converter. The switching power supply includes an LLC resonant circuit, a primary-side bridge switch group disposed on the primary side of the LLC resonant circuit, and a secondary-side bridge switch group disposed on the secondary side of the LLC resonant circuit. The switching power supply includes a charging mode and a discharging mode. The switching system includes a working mode determination module, a charging drive adjustment module, and a discharging drive adjustment module.

[0055] The operating mode determination module is used to determine the current operating mode of the switching power supply.

[0056] The charging drive adjustment module is used to continuously adjust the drive duty cycle of the secondary bridge switch group to a second target value at a predetermined rate in the charging mode, and control the drive duty cycle of the primary bridge switch group to a preset first target value, wherein the second target value is less than the first target value.

[0057] The discharge drive adjustment module is used to continuously adjust the drive duty cycle of the secondary bridge switch group to a second target value at a predetermined rate in the discharge mode, and control the drive duty cycle of the secondary bridge switch group to continuously adjust to the first target value at a predetermined rate, so that the drive duty cycle of the secondary bridge switch group is maintained at the first target value.

[0058] In the charging mode, the second target value is a variation range, and the different duty cycles within the variation range correspond to the operating frequency of the secondary bridge switch group. Furthermore, the charging drive adjustment module controls the drive duty cycle of the secondary bridge switch group to dynamically change within the variation range following the operating frequency of the secondary bridge switch group.

[0059] The operating mode determination module includes a first determination module and a second determination module. The first determination module is used to determine whether the current current is greater than or equal to a first preset current. If yes, the switching power supply is in the charging mode; if no, the switching power supply is in the discharging mode. The second determination module is used to determine whether the current current is less than or equal to a second preset current when the current current is less than the first preset current. If the second preset current is less than the first preset current, the switching power supply is in the discharging mode; if no, the switching power supply is determined to remain in the current operating state.

[0060] The working principle and operation mode of the switching power supply charging and discharging soft switching system in this embodiment are detailed in the above-mentioned switching power supply charging and discharging soft switching method, and will not be repeated here.

[0061] This invention also discloses another switching power supply charge / discharge soft switching system, which includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors. The programs include instructions for executing the switching power supply charge / discharge soft switching method as described above. The processor can be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, used to execute the relevant programs to implement the functions required by the modules in the switching power supply charge / discharge soft switching system of this application embodiment, or to execute the switching power supply charge / discharge soft switching method of this application method embodiment.

[0062] This invention also discloses a computer-readable storage medium comprising a computer program executable by a processor to perform the soft-switching method for charging and discharging a switching power supply as described above. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, magnetic tapes, magnetic disks, or optical media, such as digital versatile discs (DVDs), or semiconductor media, such as solid-state disks (SSDs).

[0063] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. The processor of an electronic device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the electronic device to perform the aforementioned soft-switching method for charging and discharging a switching power supply.

[0064] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A soft-switching method for charging and discharging of a switching power supply based on a bidirectional LLC resonant converter, the switching power supply comprising an LLC resonant circuit, a primary-side bridge switch group disposed on the primary side of the LLC resonant circuit, and a secondary-side bridge switch group disposed on the secondary side of the LLC resonant circuit, the switching power supply comprising a charging mode and a discharging mode, characterized in that, The soft switching method for charging and discharging the switching power supply includes: Determine the current operating mode of the switching power supply; The method for determining the operating mode of the switching power supply includes: Determine whether the current is greater than or equal to a first preset current. If yes, the switching power supply is in the charging mode; otherwise, the switching power supply is in the discharging mode. In the charging mode and the discharging mode, the drive duty cycle of the primary-side bridge switch group is controlled to a preset first target value; In the charging mode, it is determined whether the drive duty cycle of the secondary bridge switch group has reached a preset second target value. The second target value is less than the first target value. If not, the drive duty cycle of the secondary bridge switch group is controlled to be continuously adjusted to the second target value at a predetermined rate, and the drive duty cycle of the secondary bridge switch group is controlled to be maintained at the second target value. In the discharge mode, it is determined whether the drive duty cycle of the secondary bridge switch group has reached the first target value. If not, the drive duty cycle of the secondary bridge switch group is controlled to be continuously adjusted to the first target value at a predetermined rate, and the drive duty cycle of the secondary bridge switch group is kept at the first target value.

2. The soft-switching method for charging and discharging a switching power supply based on a bidirectional LLC resonant converter according to claim 1, characterized in that, In the charging mode, the second target value is a variation range, and the different duty cycles within the variation range correspond to the operating frequency of the secondary bridge switch group. Furthermore, the driving duty cycle of the secondary bridge switch group is dynamically changed within the variation range following the operating frequency of the secondary bridge switch group.

3. The soft-switching method for charging and discharging a switching power supply based on a bidirectional LLC resonant converter according to claim 1, characterized in that, The method for determining the operating mode of the switching power supply also includes: If the current is less than the first preset current, it is determined again whether the current is less than or equal to the second preset current. If the second preset current is less than the first preset current, the switching power supply is in the discharge mode. If not, it is determined that the switching power supply remains in the current working state.

4. The soft-switching method for charging and discharging a switching power supply based on a bidirectional LLC resonant converter according to claim 2, characterized in that, The first target value is 50%, and the range of variation is [35%, 41%].

5. A soft-switching system for charging and discharging a switching power supply based on a bidirectional LLC resonant converter, the switching power supply comprising an LLC resonant circuit, a primary-side bridge switch group disposed on the primary side of the LLC resonant circuit, and a secondary-side bridge switch group disposed on the secondary side of the LLC resonant circuit, the switching power supply comprising a charging mode and a discharging mode, characterized in that, The switching system includes a working mode determination module, a charging drive adjustment module, and a discharging drive adjustment module; The operating mode determination module is used to determine the current operating mode of the switching power supply; The charging drive adjustment module is used to continuously adjust the drive duty cycle of the secondary bridge switch group to a second target value at a predetermined rate in the charging mode, and control the drive duty cycle of the primary bridge switch group to a preset first target value, wherein the second target value is less than the first target value. The discharge drive adjustment module is used to continuously adjust the drive duty cycle of the secondary bridge switch group to a second target value at a predetermined rate in the discharge mode, and control the drive duty cycle of the secondary bridge switch group to continuously adjust to the first target value at a predetermined rate, so that the drive duty cycle of the secondary bridge switch group is maintained at the first target value; the working mode judgment module includes a first judgment module, which is used to judge whether the current is greater than or equal to a first preset current. If yes, the switching power supply is in the charging mode; if no, the switching power supply is in the discharging mode.

6. The soft-switching charging and discharging system for a switching power supply based on a bidirectional LLC resonant converter according to claim 5, characterized in that, In the charging mode, the second target value is a variation range, and the different duty cycles within the variation range correspond to the operating frequency of the secondary bridge switch group. Furthermore, the charging drive adjustment module controls the drive duty cycle of the secondary bridge switch group to dynamically change in accordance with the operating frequency of the secondary bridge switch group within the variation range.

7. The soft-switching charging and discharging system for a switching power supply based on a bidirectional LLC resonant converter according to claim 5, characterized in that, The working mode determination module further includes a second determination module. The second determination module is used to determine whether the current current is less than or equal to the second preset current when the current current is less than the first preset current. If the second preset current is less than the first preset current, the switching power supply is in the discharge mode. If not, the switching power supply is determined to remain in the current working state.

8. A soft-switching system for charging and discharging a switching power supply, characterized in that, include: One or more processors; Memory; And one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the switching power supply charge / discharge soft switching method based on a bidirectional LLC resonant converter as described in any one of claims 1 to 4.

9. A computer-readable storage medium, characterized in that, The method includes a computer program that can be executed by a processor to perform the soft switching method for charging and discharging a switching power supply based on a bidirectional LLC resonant converter as described in any one of claims 1 to 4.

Images