Resonant converter control method and resonant converter

Abstract

The invention provides a resonant converter control method and a resonant converter, and relates to the technical field of resonant converters. The resonant converter comprises a primary side switch and a corresponding rectification switch, the primary side switch is controlled by a first control signal, the rectification switch is controlled by a second control signal, and the method comprises the steps that a voltage difference value is obtained, and the voltage difference value is obtained by subtracting a voltage value of output voltage of the resonant converter from a reference voltage value; and adjusting the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference value. According to the mode, when overboot occurs in the output voltage of the resonant converter, the gain effect of the resonant converter can be further suppressed through the turn-on dead time and / or the turn-off dead time, and the output voltage impulse of the resonant converter is prevented from being too high, so that the possibility of overvoltage protection of a rear-stage converter is reduced, and the risk of downtime is reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of resonant converters, and in particular to a resonant converter control method and a resonant converter. Background Art

[0002] In the field of resonant conversion technology, with the application of AI (Artificial Intelligence), the requirements of Peak load and EDPP (Electric Data Peak Processing) have also emerged, and the slope of the load borne by the resonant converter is getting higher and higher. In this case, due to the limited frequency adjustment bandwidth of the resonant converter and insufficient suppression of the gain, the output voltage of the resonant converter will produce a large overshoot.

[0003] However, the load of the resonant converter has a specified application range in terms of voltage. When the voltage is high, it will cause overvoltage protection of the subsequent converter, resulting in the risk of downtime. Therefore, how to avoid excessive voltage surge when the voltage output of the resonant converter overshoots is an urgent problem to be solved.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The present disclosure provides a resonant converter control method and a resonant converter, which at least to a certain extent provide a method for preventing the voltage from overshooting when the voltage output by the resonant converter overshoots.

[0006] According to one aspect of the present disclosure, a resonant converter control method is provided, wherein the resonant converter includes a primary switch and a corresponding rectifier switch, wherein the primary switch is controlled by a first control signal, and the rectifier switch is controlled by a second control signal, and the method includes: obtaining a voltage difference, wherein the voltage difference is obtained by subtracting a voltage value of the resonant converter output voltage from a reference voltage value; and adjusting a turn-on dead time and / or a turn-off dead time between the first control signal and the second control signal according to the voltage difference.

[0007] In one embodiment of the present disclosure, adjusting the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference includes: when the voltage difference is less than a first voltage threshold, adjusting the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference, wherein the first voltage threshold is less than or equal to 0V.

[0008] In one embodiment of the present disclosure, it also includes: when the voltage difference is less than the second voltage threshold, maintaining the duration of the turn-on dead time and / or the turn-off dead time as a target duration, the target duration is the duration of the turn-on dead time and / or the turn-off dead time when the voltage difference is equal to the second voltage threshold, and the second voltage threshold is less than the first voltage threshold; wherein, when the voltage difference is less than the second voltage threshold, the turn-on dead time and / or the turn-off dead time causes the rectifier switch to be in an off state.

[0009] In one embodiment of the present disclosure, the second voltage threshold is determined based on a rated voltage of a load carried by the resonant converter.

[0010] In one embodiment of the present disclosure, adjusting the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference includes: calculating the inverse of the voltage difference; calculating the product of the inverse and a first coefficient to obtain the turn-on dead time; and / or calculating the product of the inverse and a second coefficient to obtain the turn-off dead time; modulating the second control signal to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

[0011] In one embodiment of the present disclosure, the method further includes: adjusting the switching frequency of the primary switch and the rectifier switch according to the voltage difference to adjust the output voltage.

[0012] According to another aspect of the present disclosure, a resonant converter is provided, comprising: a switching circuit, comprising a primary switch controlled by a first control signal; a resonant tank; a transformer; a synchronous rectification unit, comprising a rectification switch controlled by a second control signal; and a control unit, for calculating a voltage difference obtained by subtracting a voltage value of an output voltage of the resonant converter from a reference voltage value, and adjusting a turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference.

[0013] In one embodiment of the present disclosure, the control unit includes: a comparison unit, which is used to calculate a voltage difference value obtained by subtracting a voltage value of the output voltage of the resonant converter from a reference voltage value; a negation unit, which is used to calculate the opposite of the voltage difference value when the voltage difference value is less than a first voltage threshold value, wherein the first voltage threshold value is less than or equal to 0V; a dead time controller, which is used to generate a turn-on dead time and / or turn-off dead time corresponding to the opposite number; and a pulse width modulation generator, which is used to modulate the second control signal according to the turn-on dead time and / or turn-off dead time to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

[0014] In one embodiment of the present disclosure, the control unit is used to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference when the voltage difference is greater than or equal to the second voltage threshold and less than the first voltage threshold; and, when the voltage difference is less than the second voltage threshold, maintain the turn-on dead time and / or turn-off dead time at a target time, wherein the target time is the turn-on dead time and / or turn-off dead time when the voltage difference is equal to the second voltage threshold, the first voltage threshold is less than or equal to 0V, and the second voltage threshold is less than the first voltage threshold; wherein, when the voltage difference is equal to the second voltage threshold, the turn-on dead time and / or turn-off dead time causes the rectifier switch to be in an off state.

[0015] In one embodiment of the present disclosure, the control unit includes: a comparison unit, which is used to calculate a voltage difference value obtained by subtracting a voltage value of the output voltage of the resonant converter from a reference voltage value; an inversion unit, which is used to calculate the inverse of the voltage difference value when the voltage difference value is greater than or equal to the second voltage threshold and less than the first voltage threshold; a dead time controller, which is used to generate a turn-on dead time and / or turn-off dead time corresponding to the inverse number; a dead time maintainer, which is used to maintain the turn-on dead time and / or turn-off dead time at the target time when the voltage difference value is less than the second voltage threshold; and a pulse width modulation generator, which is used to modulate the second control signal according to the turn-on dead time and / or turn-off dead time to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

[0016] In one embodiment of the present disclosure, the control unit is further used to adjust the frequency of the first control signal and the second control signal according to the voltage difference, so as to adjust the switching frequency of the primary switch and the rectifier switch.

[0017] In one embodiment of the present disclosure, the control unit also includes: a frequency controller, used to generate instructions for controlling the frequencies of the first control signal and the second control signal according to the voltage difference; the pulse width modulation generator is also used to adjust the frequencies of the first control signal and the second control signal according to the instructions.

[0018] In one embodiment of the present disclosure, the second voltage threshold is determined based on a rated voltage of a load carried by the resonant converter.

[0019] In one embodiment of the present disclosure, the dead time controller is used to calculate the product of the opposite number and the first coefficient to obtain the turn-on dead time; and / or calculate the product of the opposite number and the second coefficient to obtain the turn-off dead time.

[0020] The technical solution provided by the embodiments of the present disclosure includes at least the following beneficial effects:

[0021] According to the technical solution provided by the embodiments of the present disclosure, the primary switch and the rectifier switch of the resonant converter are respectively controlled by a first control signal and a second control signal, and the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal are adjusted according to the voltage difference between the reference voltage value and the output voltage of the resonant converter. When the output voltage of the resonant converter overshoots, the gain effect of the resonant converter can be further suppressed by adjusting the turn-on dead time and / or the turn-off dead time, thereby avoiding the output voltage of the resonant converter from overshooting, reducing the possibility of overvoltage protection of the subsequent converter, and thus reducing the risk of downtime.

[0022] Furthermore, this method is simple to implement, has low cost requirements, does not require any additional devices in the resonant converter, and suppresses the gain effect stably and reliably.

[0023] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0025] Figure 1 is a schematic diagram of a resonant converter in one embodiment of the present disclosure;

[0026] Figure 2 A schematic diagram of a turn-on dead time and a turn-off dead time in one embodiment of the present disclosure;

[0027] Figure 3 Schematic diagram of an LLC resonant converter in one embodiment of the present disclosure;

[0028] Figure 4 is a schematic diagram of a control unit in one embodiment of the present disclosure;

[0029] Figure 5 is a schematic diagram of a control unit in another embodiment of the present disclosure;

[0030] Figure 6 is a schematic diagram of a control unit in yet another embodiment of the present disclosure;

[0031] Figure 7 is a schematic diagram of a control unit in yet another embodiment of the present disclosure;

[0032] Figure 8 This is a flow chart of a resonant converter control method according to an embodiment of the present disclosure;

[0033] Fig. 9 It is a schematic diagram of simulation results when a dead zone ring is not configured in one embodiment of the present disclosure;

[0034] Fig.10 It is a schematic diagram of simulation results when a dead zone ring is configured in one embodiment of the present disclosure;

[0035] Fig.11 It is a schematic diagram of simulation results before and after configuring the dead zone ring in another embodiment of the present disclosure. DETAILED DESCRIPTION

[0036] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0037] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0038] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0039] The present disclosure provides a resonant converter. Figure 1 As shown, the resonant converter may include: a switching circuit 101 , a resonant tank 102 , a transformer 103 , a synchronous rectification unit 104 and a control unit 105 .

[0040] The switching circuit 101 includes a primary switch controlled by a first control signal, and the synchronous rectification unit 104 includes a rectification switch controlled by a second control signal.

[0041] Figure 1 In, V in is the input voltage of the resonant converter and also the voltage of the front-stage bus. V0 is the output voltage of the resonant converter. The primary switch includes two switches, a first primary switch Q1 and a second primary switch Q2. The resonant tank 102 is coupled to the switching circuit 101 and the primary side of the transformer 103. The switching of Q1 and Q2 can cause the resonant tank 102 to resonate. Among them, the resonant tank 102 may include a resonant circuit composed of a capacitor and an inductor. The synchronous rectification unit 104 is coupled between the secondary side of the transformer 103 and the load, and the rectification switch may include a first synchronous rectification switch SR1 and a second synchronous rectification switch SR2. The first synchronous rectification switch SR1 has the same conduction timing as the first primary switch Q1 in the switching circuit 101, and the second synchronous rectification switch SR2 has the same conduction timing as the second primary switch Q2.

[0042] The first control signal and the second control signal are generated by the control unit 105. The control unit 105 can also calculate the voltage difference obtained by subtracting the voltage value of the output voltage of the resonant converter from the reference voltage value, and adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference.

[0043] The turn-on dead time is the time during which the synchronous rectifier switch turns on later than the primary switch with the same turn-on timing in a conduction cycle. The turn-off dead time is the time during which the synchronous rectifier switch turns off earlier than the primary switch with the same turn-on timing in a conduction cycle.

[0044] The turn-on dead time and turn-off dead time can be Figure 2 As shown, V gs is the voltage of the primary switch, V gs_SR is the voltage of the synchronous rectification switch, S1 corresponds to the first primary switch, S2 corresponds to the second primary switch, SR1 corresponds to the first synchronous rectification switch, SR2 corresponds to the second synchronous rectification switch, the time indicated by time period 1 is the turn-on dead time, and the time indicated by time period 2 is the turn-off dead time.

[0045] It should be noted that the turn-on dead time and the turn-off dead time can be the same or different. The turn-on dead time can be greater than the turn-off dead time, or the turn-on dead time can be less than the turn-off dead time. The embodiments of the present disclosure do not limit this and can be determined according to the specific configuration.

[0046] The embodiments of the present disclosure do not limit the specific type of resonant converter. In one embodiment, the resonant converter of the present disclosure may be an LLC resonant converter or any other type of resonant converter.

[0047] For example, an LLC resonant converter can be Figure 3 It should be noted that Figure 3 The structure of the LLC resonant converter shown is only exemplary, and LLC resonant converters with other structures may also be applied here.

[0048] According to the technical solution provided by the embodiments of the present disclosure, the primary switch and the rectifier switch of the resonant converter are respectively controlled by a first control signal and a second control signal, and the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal are adjusted according to the voltage difference between the reference voltage value and the output voltage of the resonant converter. When the output voltage of the resonant converter overshoots, the gain of the resonant converter can be further suppressed by adjusting the turn-on dead time and / or the turn-off dead time, thereby avoiding the output voltage of the resonant converter from overshooting, reducing the possibility of overvoltage protection of the subsequent converter, and thus reducing the risk of downtime.

[0049] Furthermore, this method is simple to implement, has low cost requirements, does not require any additional devices in the resonant converter, and suppresses the gain effect stably and reliably.

[0050] In one embodiment, the control unit 105 may be configured as follows: Figure 4 As shown, it includes: a comparison unit 1051, which is used to calculate a voltage difference value obtained by subtracting the voltage value of the output voltage of the resonant converter from the reference voltage value; an inversion unit 1052, which is used to calculate the opposite of the voltage difference value when the voltage difference value is less than a first voltage threshold value, wherein the first voltage threshold value is less than or equal to 0; a dead time controller 1053, which is used to generate a turn-on dead time and / or turn-off dead time corresponding to the opposite number; a pulse width modulation generator 1054 (PWM Generator), which is used to modulate the second control signal according to the turn-on dead time and / or turn-off dead time, so as to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

[0051] Figure 4 In, V ref The reference voltage is a reference voltage. The embodiments of the present disclosure do not limit the value of the reference voltage. In one embodiment, the reference voltage can be determined according to the rated voltage of the load. For example, the reference voltage is the optimal input voltage specified by the load.

[0052] The embodiment of the present disclosure does not limit the specific value of the first voltage threshold, and it can be set according to the needs. For example, the first voltage threshold is 0V (volt). For another example, the first voltage threshold is -0.1V. For another example, the first voltage threshold is -1V. For another example, the first voltage threshold is -2V, etc.

[0053] In one embodiment, the first voltage threshold may be determined based on the rated voltage of the load. For example, the first voltage threshold is 0.1 times, or 0.05 times, of the value obtained by subtracting the maximum value of the rated voltage of the load from the reference voltage, or other multiples greater than or equal to 0 and less than 1. It should be noted that the value obtained by subtracting the maximum value of the rated voltage of the load from the reference voltage is a negative value.

[0054] In some embodiments, when the output voltage of the resonant converter generates overshoot, the voltage difference value obtained by subtracting the voltage value of the output voltage of the resonant converter from the reference voltage value is a negative value. Therefore, when the voltage difference value is less than the first voltage threshold, it can be considered that the output voltage of the resonant converter generates overshoot, and it is necessary to adjust the turn-on dead time and / or turn-off dead time to further suppress the voltage gain of the resonant converter, thereby avoiding excessive voltage surges and damaging the load.

[0055] It should be noted that the method of modulating the second control signal to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal is to achieve voltage reduction by using a diode in parallel with the synchronous rectification switch after the synchronous rectification switch is turned off. This is a method based on a soft switch to lower the voltage gain.

[0056] In another embodiment, Figure 5 As shown, in Figure 4 On the basis of the control unit 105 shown, the control unit 105 may further include a frequency controller 1055, which is used to generate an instruction for controlling the frequency of the first control signal and the second control signal according to the voltage difference; the pulse width modulation generator 1054 may also adjust the frequency of the first control signal and the second control signal according to the instruction, thereby increasing or suppressing the voltage gain of the resonant converter, so that the output voltage of the resonant converter remains stable.

[0057] In another embodiment of the present disclosure, the control unit 105 is used to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference when the voltage difference is greater than or equal to the second voltage threshold and less than the first voltage threshold, wherein the first voltage threshold is less than or equal to 0V and the second voltage threshold is less than the first voltage threshold; and, when the voltage difference is less than the second voltage threshold, maintain the turn-on dead time and / or turn-off dead time as a target time, the target time being the turn-on dead time and / or turn-off dead time when the voltage difference is equal to the second voltage threshold.

[0058] Wherein, when the voltage difference is equal to the second voltage threshold, the turn-on dead time and / or turn-off dead time make the rectifier switch in the off state, that is, as the voltage difference increases (increases in the negative direction), the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal also increase accordingly, and when the voltage difference is equal to the second voltage threshold, the turn-on dead time and / or turn-off dead time make the rectifier switch controlled by the second control signal in the off state. And when the voltage difference continues to increase, the turn-on dead time and / or turn-off dead time are maintained at the target duration unchanged, thereby continuously maintaining the maximum gain suppression.

[0059] The embodiment of the present disclosure does not limit the specific value of the second voltage threshold. In one embodiment, the second voltage threshold is determined based on the rated voltage of the load carried by the resonant converter. For example, the second voltage threshold is 0.5 times, or 0.6 times, or 0.7 times, or 0.8 times, or 0.9 times, or other multiples greater than 0 and less than 1, of the maximum value of the rated voltage of the load minus the reference voltage.

[0060] In one embodiment, the control unit 105 may be configured as follows: Figure 6 As shown, it includes: a comparison unit 1051, which is used to calculate the voltage difference value obtained by subtracting the voltage value of the output voltage of the resonant converter from the reference voltage value; an inversion unit 1052, which is used to calculate the opposite of the voltage difference value when the voltage difference value is greater than or equal to the second voltage threshold and less than the first voltage threshold; a dead time controller 1053, which is used to generate a turn-on dead time and / or turn-off dead time corresponding to the opposite number; a dead time maintainer 1056, which is used to maintain the turn-on dead time and / or turn-off dead time as the target duration when the voltage difference value is less than the second voltage threshold; a pulse width modulation generator 1054, which is used to modulate the second control signal according to the turn-on dead time and / or turn-off dead time to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

[0061] In another embodiment, Figure 7 As shown, in Figure 6 Based on the control unit 105 shown, the control unit 105 may further include a frequency controller 1055 .

[0062] In one embodiment, the dead time controller is used to calculate the product of the opposite number and the first coefficient to obtain the turn-on dead time; and / or calculate the product of the opposite number and the second coefficient to obtain the turn-off dead time.

[0063] The first coefficient and the second coefficient may be the same or different. The first coefficient may be greater than the second coefficient or less than the second coefficient, and the embodiments of the present disclosure do not limit this.

[0064] The embodiment of the present disclosure also provides a resonant converter control method, wherein the resonant converter includes a primary switch and a corresponding rectifier switch, the primary switch is controlled by a first control signal, and the rectifier switch is controlled by a second control signal, such as Figure 8 As shown, the resonant converter control method may include the following S801 to S802. For the specific implementation of S801 to S802, reference may be made to the above-mentioned embodiment corresponding to the resonant converter.

[0065] S801, obtaining a voltage difference value, where the voltage difference value is obtained by subtracting a voltage value of the resonant converter output voltage from a reference voltage value.

[0066] S802: Adjust a turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference.

[0067] According to the technical solution provided by the embodiments of the present disclosure, the primary switch and the rectifier switch of the resonant converter are respectively controlled by a first control signal and a second control signal, and the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal are adjusted according to the voltage difference between the reference voltage value and the output voltage of the resonant converter. When the output voltage of the resonant converter overshoots, the gain effect of the resonant converter can be further suppressed by adjusting the turn-on dead time and / or the turn-off dead time, thereby avoiding the output voltage of the resonant converter from overshooting, reducing the possibility of overvoltage protection of the subsequent converter, and thus reducing the risk of downtime.

[0068] Furthermore, this method is simple to implement, has low cost requirements, does not require any additional devices in the resonant converter, and suppresses the gain effect stably and reliably.

[0069] In one embodiment, adjusting the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference may include: when the voltage difference is less than a first voltage threshold, adjusting the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference, wherein the first voltage threshold is less than or equal to 0V.

[0070] In one embodiment, the resonant converter control method may also include: when the voltage difference is less than the second voltage threshold, maintaining the duration of the turn-on dead time and / or the turn-off dead time as the target duration, the target duration being the duration of the turn-on dead time and / or the turn-off dead time when the voltage difference is equal to the second voltage threshold, and the second voltage threshold is less than the first voltage threshold; wherein, when the voltage difference is less than the second voltage threshold, the turn-on dead time and / or the turn-off dead time causes the rectifier switch to be in the off state.

[0071] In one embodiment, the second voltage threshold is determined based on a rated voltage of a load carried by the resonant converter.

[0072] In one embodiment, adjusting the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference may include: calculating the inverse of the voltage difference; calculating the product of the inverse and the first coefficient to obtain the turn-on dead time; and / or calculating the product of the inverse and the second coefficient to obtain the turn-off dead time; modulating the second control signal to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

[0073] In one embodiment, the switching frequencies of the primary switch and the rectifier switch may be adjusted according to the voltage difference to adjust the output voltage.

[0074] In one embodiment, the overshoot peak value is also affected by the PFC (Power Factor Correction) circuit. When switching from a heavy load to a light load, the voltage loop integration is still there, resulting in a high bus voltage charge, that is, a high input voltage of the resonant converter. At this time, the bulk voltage can be prevented from rising by manual de-integration.

[0075] The effects of the technical solutions provided by the embodiments of the present disclosure are illustrated below by taking two groups of simulation experiments as examples.

[0076] Simulation 1: Fig. 9 As shown, when no dead zone ring is set (such as Figure 4 As shown, the overshoot peak voltage is 12.51V (volts), when the load slope is 2.5A / microseconds and the inversion unit 1052 and the dead time controller 1053 are formed. Fig.10 As shown in FIG. 1 , when the dead-band loop is set and the slope of the load is 2.5A / μs, the peak voltage of the overshoot is 12.26V.

[0077] Simulation 2: Fig.11 As shown in FIG. 1 , when the dead-band loop is not set, the peak voltage of the overshoot is 13 V. When the dead-band loop is set and other conditions are exactly the same, the peak voltage of the overshoot is 12.73 V.

[0078] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope of the present disclosure is indicated by the appended claims.

Claims

1. A resonant converter control method, characterized in that: The resonant converter includes a primary switch and a corresponding rectifier switch, wherein the primary switch is controlled by a first control signal and the rectifier switch is controlled by a second control signal, including: Obtaining a voltage difference value, wherein the voltage difference value is obtained by subtracting a voltage value of the resonant converter output voltage from a reference voltage value; According to the voltage difference, a turn-on dead time and / or a turn-off dead time between the first control signal and the second control signal are adjusted.

2. The method according to claim 1, characterized in that: The adjusting, according to the voltage difference, the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal comprises: When the voltage difference is less than a first voltage threshold, the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal are adjusted according to the voltage difference, wherein the first voltage threshold is less than or equal to 0V.

3. The method according to claim 2, characterized in that Also includes: When the voltage difference is less than a second voltage threshold, maintaining the duration of the turn-on dead time and / or the turn-off dead time as a target duration, the target duration being the duration of the turn-on dead time and / or the turn-off dead time when the voltage difference is equal to the second voltage threshold, and the second voltage threshold is less than the first voltage threshold; Wherein, when the voltage difference is less than a second voltage threshold, the turn-on dead time and / or turn-off dead time causes the rectifier switch to be in an off state.

4. The method according to claim 3, characterized in that: The second voltage threshold is determined based on a rated voltage of a load carried by the resonant converter.

5. The method according to any one of claims 1 to 4, characterized in that: The adjusting, according to the voltage difference, the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal comprises: Calculating the inverse of the voltage difference; Calculating the product of the opposite number and the first coefficient to obtain the turn-on dead time; and / or calculating the product of the opposite number and the second coefficient to obtain the turn-off dead time; The second control signal is modulated to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

6. The method according to any one of claims 1 to 4, characterized in that: Also includes: According to the voltage difference, the switching frequencies of the primary switch and the rectifier switch are adjusted to adjust the output voltage.

7. A resonant converter, characterized in that: include: A switching circuit, comprising a primary switch controlled by a first control signal; Resonance tank; transformer; a synchronous rectification unit, comprising a rectification switch controlled by a second control signal; A control unit is used to calculate a voltage difference obtained by subtracting a voltage value of the output voltage of the resonant converter from a reference voltage value, and to adjust a turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference.

8. The resonant converter according to claim 7, characterized in that: The control unit comprises: A comparison unit, configured to calculate a voltage difference value obtained by subtracting a voltage value of an output voltage of the resonant converter from a reference voltage value; a negation unit, configured to calculate a negative number of the voltage difference when the voltage difference is less than a first voltage threshold, wherein the first voltage threshold is less than or equal to 0V; A dead time controller, used to generate a turn-on dead time and / or turn-off dead time corresponding to the inverse number; A pulse width modulation generator is used to modulate the second control signal according to the turn-on dead time and / or turn-off dead time to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

9. The resonant converter according to claim 7, characterized in that: The control unit is configured to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal according to the voltage difference when the voltage difference is greater than or equal to the second voltage threshold and less than the first voltage threshold; And, when the voltage difference is less than the second voltage threshold, the duration of the turn-on dead time and / or the turn-off dead time is maintained as a target duration, the target duration is the duration of the turn-on dead time and / or the turn-off dead time when the voltage difference is equal to the second voltage threshold, the first voltage threshold is less than or equal to 0V, and the second voltage threshold is less than the first voltage threshold; Wherein, when the voltage difference is equal to the second voltage threshold, the turn-on dead time and / or turn-off dead time causes the rectifier switch to be in the turn-off state.

10. The resonant converter according to claim 9, characterized in that The control unit comprises: A comparison unit, configured to calculate a voltage difference value obtained by subtracting a voltage value of an output voltage of the resonant converter from a reference voltage value; a negation unit, configured to calculate a negation of the voltage difference when the voltage difference is greater than or equal to the second voltage threshold and less than the first voltage threshold; A dead time controller, used to generate a turn-on dead time and / or turn-off dead time corresponding to the inverse number; A dead time maintainer, configured to maintain the duration of the on-dead time and / or the off-dead time at the target duration when the voltage difference is less than the second voltage threshold; A pulse width modulation generator is used to modulate the second control signal according to the turn-on dead time and / or turn-off dead time to adjust the turn-on dead time and / or turn-off dead time between the first control signal and the second control signal.

11. The resonant converter according to claim 8 or 10, characterized in that: The control unit is further configured to adjust the frequencies of the first control signal and the second control signal according to the voltage difference, so as to adjust the switching frequencies of the primary switch and the rectifier switch.

12. The resonant converter according to claim 11, characterized in that The control unit further comprises: a frequency controller, configured to generate an instruction for controlling the frequencies of the first control signal and the second control signal according to the voltage difference; The pulse width modulation generator is further used to adjust the frequencies of the first control signal and the second control signal according to the instruction.

13. The resonant converter according to claim 9 or 10, characterized in that: The second voltage threshold is determined based on a rated voltage of a load carried by the resonant converter.

14. The resonant converter according to claim 7 or 10, characterized in that: The dead time controller is used to calculate the product of the opposite number and the first coefficient to obtain the opening dead time; and / or, The product of the inverse number and the second coefficient is calculated to obtain the turn-off dead time.

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