LLC resonant converter control method, device and equipment and LLC resonant converter

Abstract

The invention discloses an LLC resonant converter control method, device and equipment and an LLC resonant converter, in the current period, it is determined that the LLC resonant converter is in an intermittent state, an upper tube of an LLC resonant conversion circuit is controlled to be switched off and a lower tube of the LLC resonant conversion circuit is controlled to be switched on or the upper tube and the lower tube of the LLC resonant conversion circuit are controlled to be switched off, and in the next period, after it is determined that the LLC resonant converter is switched from the intermittent state to a non-intermittent state, the LLC resonant converter is switched off. The upper tube and the lower tube are controlled to be switched on or switched off according to the first comparison value and the second comparison value, the first comparison value is smaller than the second comparison value, and the sum value of the first comparison value and the second comparison value is a periodic value. When the LLC resonant converter is in the intermittent state, the upper tube is controlled to be switched off, the lower tube is controlled to be switched on, or the upper tube is controlled to be switched on, and the lower tube is controlled to be switched off, so that the resonant current flows through the switched-on switching tube, the switched-on resonant inductor, the switched-on resonant capacitor and the switched-on primary side of the transformer, the amplitude of the resonant current is attenuated, and the probability that the voltage stress of the SR MOS tube exceeds the standard is reduced; and the damage probability of the MOS tube is reduced.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to an LLC resonant converter control method, device, equipment and LLC resonant converter. Background Art

[0002] LLC resonant converter is a type of switching power supply. In order to improve power density, the switching frequency is increased, which directly leads to an increase in switching losses. LLC resonant converter has the characteristics of soft switching, which can achieve ZVS of the primary switch tube of the LLC resonant conversion circuit and ZCS of the secondary rectifier tube of the LLC resonant conversion circuit in the LLC resonant converter within a wide range, thereby reducing switching losses.

[0003] In order to achieve a wide range of output, LLC resonant converter usually adopts a scheme of switching between multiple wave generation modes such as PFM (Pulse Frequency Modulation), PFM+PWM (Pulse-Width Modulation), PWM and intermittent wave generation. The wave generation modes of PFM, PFM+PWM, PWM and intermittent wave generation all adopt symmetrical wave generation. When the symmetrical wave generation mode is used to enter the non-intermittent zone from the intermittent zone, such as the PWM zone, since the switch tubes do not generate waves in the intermittent zone, when switching from the intermittent zone to the non-intermittent zone, a comparison is made based on the CMP value, and then each switch tube is driven according to the order of the comparison.

[0004] In the intermittent zone, each switch tube does not generate waves, the resonant circuit resonates freely, and the switch tube directly connected to the transformer will continuously charge and discharge in the direction of the resonant current. When the intermittent zone is exited, the Vds of the switch tube directly connected to the transformer is uncontrollable, and there may be a probability of hard switch conduction. When the switch tube directly connected to the transformer is hard turned on, the large voltage change rate (dv / dt) and current change rate (di / dt) of the primary side are coupled to the secondary SR (Synchronous Rectification) MOS tube through the main transformer, which may cause the voltage stress of the SR MOS tube to exceed the standard and damage the MOS tube. Summary of the invention

[0005] The present invention provides an LLC resonant converter control method, device, equipment and LLC resonant converter, which are used to solve the problem in the prior art that after a switch tube directly connected to a transformer in an LLC resonant converter is hard-turned on, large dv / dt and di / dt on the primary side are coupled to a secondary SR MOS tube through a main transformer, which may cause the voltage stress of the SR MOS tube to exceed the standard and damage the MOS tube.

[0006] In a first aspect, an embodiment of the present application provides a method for controlling an LLC resonant converter, wherein the LLC resonant converter includes an LLC resonant conversion circuit, and the method includes:

[0007] In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off;

[0008] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube and the lower tube are controlled to be turned on or off according to the first comparison value and the second comparison value, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a cycle value.

[0009] In an optional embodiment, the method further includes:

[0010] In the next cycle, the start time of the next cycle and the half cycle time of the next cycle are used as the switching time for controlling the opening or closing of the upper tube and the lower tube.

[0011] In an optional implementation, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0012] In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off, including:

[0013] If the switching tubes that are preferentially controlled to be turned on are the first upper tube and the first lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned off, and the first lower tube and the second lower tube are controlled to be turned on.

[0014] In an optional implementation, in the next cycle, after determining that the LLC resonant converter is switched from the intermittent state to the non-intermittent state, controlling the upper tube and the lower tube to be turned on or off according to the first comparison value and the second comparison value includes:

[0015] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the second lower tube to be turned off according to the first comparison value, and controlling the second upper tube to be turned on according to the second comparison value;

[0016] The half period of the next period is used as the switching period, the first lower tube is controlled to be turned off according to the second comparison value, and the first upper tube is controlled to be turned on according to the first comparison value.

[0017] In an optional implementation, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0018] In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off, including:

[0019] If the switching tubes that are preferentially controlled to be turned on are the second upper tube and the second lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned on, and the first lower tube and the second lower tube are controlled to be turned off.

[0020] In an optional implementation, in the next cycle, after determining that the LLC resonant converter is switched from the intermittent state to the non-intermittent state, controlling the upper tube and the lower tube to be turned on or off according to the first comparison value and the second comparison value includes:

[0021] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the first lower tube to be turned off according to the first comparison value, and controlling the first upper tube to be turned on according to the second comparison value;

[0022] The half period of the next period is used as the switching period, the second lower tube is controlled to be turned off according to the second comparison value, and the second upper tube is controlled to be turned on according to the first comparison value.

[0023] In a second aspect, an embodiment of the present application provides a control device for an LLC resonant converter, comprising:

[0024] A first control module is used for, in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, controlling the upper tube in the LLC resonant conversion circuit to turn off, controlling the lower tube in the LLC resonant conversion circuit to turn on, or controlling the upper tube to turn on, controlling the lower tube to turn off according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state;

[0025] The second control module is used to control the opening or closing of the upper tube and the lower tube according to the first comparison value and the second comparison value after determining in the next cycle that the LLC resonant converter switches from the intermittent state to the non-intermittent state, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a periodic value.

[0026] In an optional embodiment, the second control module is further used for:

[0027] In the next cycle, the start time of the next cycle and the half cycle time of the next cycle are used as the switching time for controlling the opening or closing of the upper tube and the lower tube.

[0028] In an optional embodiment, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0029] The first control module is specifically used for:

[0030] If the switching tubes that are preferentially controlled to be turned on are the first upper tube and the first lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned off, and the first lower tube and the second lower tube are controlled to be turned on.

[0031] In an optional embodiment, the second control module is specifically configured to:

[0032] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the second lower tube to be turned off according to the first comparison value, and controlling the second upper tube to be turned on according to the second comparison value;

[0033] The half period of the next period is used as the switching period, the first lower tube is controlled to be turned off according to the second comparison value, and the first upper tube is controlled to be turned on according to the first comparison value.

[0034] In an optional embodiment, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0035] The first control module is specifically used for:

[0036] If the switching tubes that are preferentially controlled to be turned on are the second upper tube and the second lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned on, and the first lower tube and the second lower tube are controlled to be turned off.

[0037] In an optional embodiment, the second control module is specifically configured to:

[0038] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the first lower tube to be turned off according to the first comparison value, and controlling the first upper tube to be turned on according to the second comparison value;

[0039] The half period of the next period is used as the switching period, the second lower tube is controlled to be turned off according to the second comparison value, and the second upper tube is controlled to be turned on according to the first comparison value.

[0040] In a third aspect, an embodiment of the present application provides a control device for an LLC resonant converter, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of any one of the methods described in the first aspect when executing the computer program.

[0041] In a fourth aspect, an embodiment of the present application provides an LLC resonant converter, comprising an LLC resonant conversion circuit and a control device of the LLC resonant converter as described in the third aspect.

[0042] The beneficial effects of the present invention are as follows:

[0043] An LLC resonant converter control method, apparatus, device and LLC resonant converter provided by an embodiment of the present application, the method comprising: in a current cycle, after determining that the LLC resonant converter is in an intermittent state, preferentially controlling the on switch tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, controlling the upper tube in the LLC resonant conversion circuit to be turned off, and controlling the lower tube in the LLC resonant conversion circuit to be turned on, or controlling the upper tube to be turned on and controlling the lower tube to be turned off, in the next cycle, after determining that the LLC resonant converter switches from an intermittent state to a non-intermittent state, controlling the upper tube and the lower tube to be turned on or off according to a first comparison value and a second comparison value, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a cycle value. When the LLC resonant converter is in an intermittent state, the upper tube is controlled to be turned off and the lower tube is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off, so as to realize soft turning on of the tube connected to the transformer, so that the resonant current flows through the turned-on switch tube, the resonant inductor, the resonant capacitor and the primary side of the transformer in the intermittent state, thereby attenuating the amplitude of the resonant current, reducing the large di / dt and dv / dt caused by the hard turning on of the primary side switch tube, reducing the amplitude of the coupling current, reducing the loss of the switch tube, reducing the voltage overcharge coupled to the secondary side, and when the LLC resonant converter exits the intermittent state, the Vds of the tube to be turned on is reduced to 0V in advance, reducing the probability of excessive voltage stress of the SR MOS tube, thereby reducing the probability of damage to the MOS tube, and improving the performance of the LLC resonant converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0045] Figure 1 A schematic diagram of the structure of an LLC resonant converter provided for related technology;

[0046] Figure 2 A schematic diagram of the structure of another LLC resonant converter provided in the related art;

[0047] Figure 3 A schematic diagram of a symmetrical wave waveform provided for related technology;

[0048] Figure 4 A schematic diagram of a driving waveform in an intermittent state and a non-intermittent state provided for the related technology;

[0049] Figure 5 A schematic diagram of the flow direction of a resonant current provided for related technology;

[0050] Figure 6 A flow chart of a LLC resonant converter control method is provided for an embodiment of the present application;

[0051] Figure 7 A schematic diagram of a driving waveform provided in an embodiment of the present application;

[0052] Figure 8 A schematic diagram of a driving waveform in an intermittent state and a non-intermittent state provided in an embodiment of the present application;

[0053] Fig. 9 A schematic diagram of another driving waveform in an intermittent state and a non-intermittent state provided in an embodiment of the present application;

[0054] Fig.10 A schematic diagram of another driving waveform in an intermittent state and a non-intermittent state provided in an embodiment of the present application;

[0055] Fig.11a A schematic diagram of a resonant current flow provided in an embodiment of the present application;

[0056] Fig.11b A schematic diagram of another resonant current flow direction provided in an embodiment of the present application;

[0057] Fig.11c A schematic diagram of another resonant current flow direction provided in an embodiment of the present application;

[0058] Fig.11d A schematic diagram of another resonant current flow direction provided in an embodiment of the present application;

[0059] Fig.11e A schematic diagram of another resonant current flow direction provided in an embodiment of the present application;

[0060] Fig.11f A schematic diagram of another resonant current flow direction provided in an embodiment of the present application;

[0061] Fig.12 A schematic diagram of another driving waveform provided in an embodiment of the present application;

[0062] Fig.13 A schematic diagram of a driving waveform in an intermittent state and a non-intermittent state provided in an embodiment of the present application;

[0063] Fig.14 A schematic diagram of another driving waveform in an intermittent state and a non-intermittent state provided in an embodiment of the present application;

[0064] Fig.15 A schematic diagram of another driving waveform in an intermittent state and a non-intermittent state provided in an embodiment of the present application;

[0065] Fig.16 A schematic diagram of another driving waveform in an intermittent state and a non-intermittent state provided in an embodiment of the present application;

[0066] Fig.17 A schematic diagram of the structure of a control device for an LLC resonant converter provided in an embodiment of the present application;

[0067] Fig.18 A schematic diagram of the structure of a control device for an LLC resonant converter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] like Figure 1 As shown, it is a structural schematic diagram of an LLC resonant converter provided by the related art, Figure 1 The LLC resonant converter in the embodiment is a single-phase full-bridge LLC resonant converter, the primary side of which adopts a full-bridge structure and the secondary side adopts full-wave rectification. The first switch tube Q1 and the second switch tube Q2 are connected in series to form a leading bridge arm of the primary side, the third switch tube Q3 and the fourth switch tube Q4 are connected in series to form a lagging bridge arm of the primary side, the first diode D1 is a body diode corresponding to the first switch tube Q1, the second diode D2 is a body diode corresponding to the second switch tube Q2, the third diode D3 is a body diode corresponding to the third switch tube Q3, the fourth diode D4 is a body diode corresponding to the fourth switch tube Q4, the first capacitor C1 is a junction capacitor corresponding to the first switch tube Q1, the second capacitor C2 is a junction capacitor corresponding to the second switch tube Q2, the third capacitor C3 is a junction capacitor corresponding to the third switch tube Q3, the fourth capacitor C4 is a junction capacitor corresponding to the fourth switch tube Q4, the capacitor Cr is a resonant capacitor, the inductor Lr and the inductor Lm are resonant inductors, the fifth switch tube Sr1 and the sixth switch tube Sr2 are two synchronous rectification MOS tubes of the secondary side, the capacitor C0 is an output filter capacitor, and RLd is a load. In the LLC resonant converter, the resonant element includes a first resonant inductor Lr, a second resonant inductor Lm and a resonant capacitor Cr, wherein the second resonant inductor Lm is connected in parallel with the transformer T and can be realized by the excitation inductor of the transformer T. The resonant capacitor Cr is connected in series in the primary loop and also plays a role of direct current isolation.

[0070] like Figure 2 As shown, it is a structural schematic diagram of another LLC resonant converter provided by the related art, Figure 2 The LLC resonant converter in is a single-phase half-bridge LLC resonant converter, such as Figure 2 As shown, the primary side of the LLC resonant converter adopts a half-bridge structure, that is, the primary side only includes a bridge arm composed of a seventh switch tube Q5 and an eighth switch tube Q6 connected in series, wherein the fifth diode D5 is a body diode corresponding to the seventh switch tube Q5, the sixth diode D6 is a body diode corresponding to the eighth switch tube Q6, the fifth capacitor C5 is a junction capacitor corresponding to the seventh switch tube Q5, the sixth capacitor C6 is a junction capacitor corresponding to the eighth switch tube Q6, the capacitor Cr is a resonant capacitor, the inductor Lr and the inductor Lm are resonant inductors, the ninth switch tube Sr3 and the tenth switch tube Sr4 are two synchronous rectification MOS tubes on the secondary side, the capacitor C0 is an output filter capacitor, and RLd is a load.

[0071] Figure 1 The switch tube directly connected to the transformer is the fourth switch tube Q4. Figure 2 The switch tube directly connected to the transformer is the eighth switch tube Q6. Figure 1 The LLC resonant circuit shown is taken as an example for detailed description.

[0072] like Figure 3 As shown, it is a waveform diagram of a symmetrical wave provided by the related technology, wherein the driving waveforms of the first switch tube Q1 and the fourth switch tube Q4 are consistent, the driving waveforms of the second switch tube Q2 and the third switch tube Q3 are consistent, and the driving waveforms of the first switch tube Q1 and the second switch tube Q2 have a phase difference of 180 degrees.

[0073] like Figure 4 As shown in the figure, it is a waveform diagram of the switching of the first wave when exiting the intermittent zone. Figure 4 It can be seen that in the intermittent area, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 do not send waveforms. According to the existing PWM register, when the time base counter counts to 0, the value in the shadow register is loaded to update the CMP value used for action. According to the comparison action sequence, the first comparison and issuance are the drive waveforms of the first switch tube Q1 and the fourth switch tube Q4. After half a carrier cycle, the drive waveforms of the second switch tube Q2 and the third switch tube Q3 are issued.

[0074] It should be noted that Figure 4 In the embodiment, the driving waveforms of the second switch tube Q2 and the third switch tube Q3 are at a high level for a period of time. Since the period of time is shorter than the dead time period, even at a high level, the second switch tube Q2 and the third switch tube Q3 will not be driven to turn on.

[0075] like Figure 5 As shown, Figure 1Schematic diagram of the flow direction of the resonant current of the LLC resonant converter during free resonance, the resonant current Ir flows from one end of the resonant capacitor Cr, through the first resonant inductor Lr, the second resonant inductor Lm and the fourth switch tube Q4, to the negative electrode of the power supply, and the resonant current Ir is coupled to the secondary side of the transformer T through the transformer T, forming the following Figure 5 The coupling current shown in FIG. 1 flows through the filter capacitor C0 and the sixth switch tube Sr2 . If the dv / dt and di / dt of the resonant current Ir are large, the coupling current may exceed the voltage stress of the sixth switch tube Sr2 , thereby damaging the sixth switch tube Sr2 .

[0076] Based on the above technical problems, an embodiment of the present application provides an LLC resonant converter control method, wherein the LLC resonant converter includes an LLC resonant conversion circuit, such as Figure 6 As shown, the method comprises the following steps:

[0077] S601, in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off;

[0078] S602. In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube and the lower tube are controlled to be turned on or off according to a first comparison value and a second comparison value, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a cycle value.

[0079] In an embodiment of the present application, in the current cycle, after determining that the LLC resonant converter is in an intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, and the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off. In the next cycle, after determining that the LLC resonant converter is switched from an intermittent state to a non-intermittent state, the upper tube and the lower tube are controlled to be turned on or off according to a first comparison value and a second comparison value, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is the periodic value. When the LLC resonant converter is in an intermittent state, the upper tube is controlled to be turned off and the lower tube is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off, so as to realize the soft turning on of the tube connected to the transformer, so that the resonant current flows through the turned-on switch tube, the resonant inductor, the resonant capacitor and the primary side of the transformer in the intermittent state, thereby attenuating the amplitude of the resonant current, reducing the large di / dt and dv / dt caused by the hard turning on of the primary side switch tube, reducing the amplitude of the coupling current, reducing the loss of the switch tube, reducing the voltage overcharge coupled to the secondary side, and when the LLC resonant converter exits the intermittent state, the Vds of the tube to be turned on is reduced to 0V in advance, reducing the probability of the SR MOS tube voltage stress exceeding the standard, thereby reducing the probability of the MOS tube being damaged, and improving the performance of the LLC resonant converter.

[0080] It should be noted that, refer to Figure 1 The first switch tube Q1 is the upper tube of the leading bridge arm (first bridge arm), that is, the first upper tube, the second switch tube Q2 is the lower tube of the leading bridge arm, that is, the first lower tube, the third switch tube Q3 is the upper tube of the lagging bridge arm (second bridge arm), that is, the second upper tube, and the fourth switch tube Q4 is the lower tube of the lagging bridge arm, that is, the second lower tube.

[0081] In a specific implementation, after determining that the LLC resonant converter is in an intermittent state in the current cycle, controlling the upper tube to turn off and controlling the lower tube to turn on, or controlling the upper tube to turn on and controlling the lower tube to turn off is determined according to the pre-set driving sequence of the switch tubes when the LLC resonant converter switches from the intermittent state to the non-intermittent state. Specifically, it can be determined according to the switch tube that is preferentially controlled to be turned on, for example, combined with Figure 1At the switching moment from the intermittent state to the non-intermittent state, if the switch tubes driven first are preset as the upper tube of the leading bridge arm and the lower tube of the lagging bridge arm, that is, the first switch tube Q1 and the fourth switch tube Q4, then after determining that the LLC resonant converter is in the intermittent state, the upper tubes (the first switch tube Q1 and the third switch tube Q3) of the LLC resonant conversion circuit are controlled to be turned off, and the lower tubes (the second switch tube Q2 and the fourth switch tube Q4) of the LLC resonant conversion circuit are controlled to be turned on; if the switch tubes driven first are preset as the lower tube of the leading bridge arm and the upper tube of the lagging bridge arm, that is, the second switch tube Q2 and the third switch tube Q3, then after determining that the LLC resonant converter is in the intermittent state, the upper tubes (the first switch tube Q1 and the third switch tube Q3) of the LLC resonant conversion circuit are controlled to be turned on, and the lower tubes (the second switch tube Q2 and the fourth switch tube Q4) of the LLC resonant conversion circuit are controlled to be turned off.

[0082] The embodiments of the present application are described in detail below based on the above two situations.

[0083] Case 1: The switch tubes to be driven first are preset to be the upper tube of the leading bridge arm and the lower tube of the lagging bridge arm, that is, the first switch tube Q1 and the fourth switch tube Q4.

[0084] In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off and the lower tube is controlled to be turned on. In the next cycle, after it is determined that the LLC resonant converter switches from an intermittent state to a non-intermittent state, the upper tube of the leading bridge arm and the lower tube of the lagging bridge arm are controlled to be turned off and on according to the first comparison value, and the lower tube of the leading bridge arm and the upper tube of the lagging bridge arm are controlled to be turned on and off according to the second comparison value.

[0085] For example, Figure 1 For the LLC resonant converter shown, if the switch tubes to be driven first are pre-set to be the first switch tube Q1 and the fourth switch tube Q4, in the current cycle, when it is determined that the LLC resonant converter is in the intermittent state, the first switch tube Q1 and the third switch tube Q3 are controlled to be turned off, and the second switch tube Q2 and the fourth switch tube Q4 are controlled to be turned on. In the next cycle, after it is determined that the LLC resonant converter switches from the intermittent state to the non-intermittent state, a drive signal for controlling the first switch tube Q1 and the third switch tube Q3 is generated according to the first comparison value CMP1, and a drive signal for controlling the second switch tube Q2 and the fourth switch tube Q4 is generated according to the second comparison value CMP2.

[0086] Specifically, the first switch tube Q1 and the third switch tube Q3 are controlled to be turned on and off according to the first comparison value CMP1, and the second switch tube Q2 and the fourth switch tube Q4 are controlled to be turned on and off according to the second comparison value CMP2.

[0087] like Figure 7, which is a schematic diagram of a driving waveform in an intermittent state provided by an embodiment of the present application. Figure 7 It can be seen that the driving waveforms of the first switch tube Q1 and the second switch tube Q2 are complementary, and the driving waveforms of the third switch tube Q3 and the fourth switch tube Q4 are complementary. At the end of the previous cycle, the driving signals of the first switch tube Q1 and the fourth switch tube Q4 are high level, controlling the first switch tube Q1 and the fourth switch tube Q4 to be turned on, and the driving signals of the second switch tube Q2 and the third switch tube Q3 are low level, controlling the second switch tube Q2 and the third switch tube Q3 to be turned off, CTR (time base counter) = 0, at this time, CTR restarts counting, when CTR counts up to CMP1, the driving signal of the first switch tube Q1 is triggered to switch from high level to low level, and the driving signal of the second switch tube Q2 is triggered to switch from low level to high level, when CTR counts up to CMP2, the trigger The driving signal of the third switch tube Q3 switches from a low level to a high level, triggering the driving signal of the fourth switch tube Q4 to switch from a high level to a low level. When CTR=PRD, CTR starts to decrease. When CTR counts down to=MP2, the driving signal of the third switch tube Q3 is triggered to switch from a high level to a low level, and the driving signal of the fourth switch tube Q4 is triggered to switch from a low level to a high level. When CTR counts down to CMP1, the driving signal of the first switch tube Q1 is triggered to switch from a low level to a high level, and the driving signal of the second switch tube Q2 is triggered to switch from a high level to a low level. When CTR=0, the cycle ends.

[0088] In the specific implementation, Figure 8 As shown, it is a schematic diagram of a driving change of an exit intermittent moment provided by an embodiment of the present application, from Figure 8 It can be seen from the figure that in the intermittent state, the first switch tube Q1 and the third switch tube Q3 are turned off, and the second switch tube Q2 and the fourth switch tube Q4 are turned on. When the intermittent state needs to be exited, that is, when the intermittent state is switched to the non-intermittent state, the CMP value updates the register at the zero crossing point. The first group of drives issued after the update, that is, the first group of drives issued at the switching moment, are the drives of the first switch tube Q1 and the fourth switch tube Q4. The timing starts from the switching moment. When CTR counts up to the first comparison value CMP1, the first switch tube Q1 and the fourth switch tube Q4 are driven. The driving signal of Q4 is converted to a low level. When CTR counts upward to the second comparison value CMP2, the driving signals driving the second switch tube Q2 and the third switch tube Q3 are converted to a high level. After counting to PRD, CTR starts to decrease. When CTR counts downward to the second comparison value CMP2, the driving signals driving the second switch tube Q2 and the third switch tube Q3 are converted to a low level. When CTR counts downward to the first comparison value CMP1, the driving signals driving the first switch tube Q1 and the fourth switch tube Q4 are converted to a high level.

[0089] from Figure 7 and Figure 8 It can be seen that in the embodiment of the present application, in the intermittent state, the Figure 7 The driving waveform shown controls the switch tube. Figure 8 Although the driving signal of the third switch tube Q3 is at a high level for a period of time in the intermittent state, since the period is shorter than the dead zone period, the driving signal cannot actually be issued, that is, the level change within the period can be ignored.

[0090] Figure 7 and Figure 8 According to the value of the CMP register, the driving signal of the second switch tube Q2 and the driving signal of the fourth switch tube Q4 in the intermittent state are controlled to be the on signal, and the driving signal of the first switch tube Q1 and the third switch tube Q3 are controlled to be the off signal, that is, the second switch tube Q2 and the fourth switch tube Q4 are controlled to be turned on, and the first switch tube Q1 and the third switch tube Q3 are controlled to be turned off.

[0091] from Figure 8 It can be seen that at the start of the current cycle, the driving signal of the first switch tube Q1 is high, the driving signal of the second switch tube Q2 is low, the driving signal of the third switch tube Q3 is low, and the driving signal of the fourth switch tube Q4 is high. When CTR counts up to CMP1', the driving signal of the first switch tube Q1 is controlled to switch to a low level, the driving signal of the second switch tube Q2 is controlled to switch to a high level, the driving signal of the third switch tube Q3 remains at a low level, and the driving signal of the fourth switch tube Q4 remains at a high level. When CTR counts up to CMP2', the driving signal of the third switch tube Q3 is controlled to switch to a high level, and the driving signal of the fourth switch tube Q4 is controlled to switch to a high level. When CTR=PRD, CTR starts to decrease. When CTR counts down to CMP2', the drive signal of the third switch tube Q3 is controlled to switch to a low level, and the drive signal of the fourth switch tube Q4 is controlled to switch to a high level. The drive signal of the first switch tube Q1 and the drive signal of the second switch tube Q2 remain unchanged. When CTR counts down to CMP1', the drive signal of the first switch tube Q1 is controlled to switch to a high level, and the drive signal of the second switch tube Q2 is controlled to switch to a low level. The drive signal of the third switch tube Q3 and the drive signal of the fourth switch tube Q4 remain unchanged.

[0092] Figure 8 In the embodiment, the high level duration of the driving signal of the third switch tube Q3 is shorter than the dead zone duration, and thus can be ignored. Figure 8It can be seen that the driving signal of the first switch tube Q1 and the driving signal of the third switch tube Q3 are at a low level, and the driving signal of the second switch tube Q2 and the driving signal of the fourth switch tube Q4 are at a high level, so as to control the first switch tube Q1 and the third switch tube Q3 to be turned off, and control the second switch tube Q2 and the fourth switch tube Q4 to be turned on.

[0093] In another embodiment, in the intermittent state, an AQ (Action-Qualifier) ​​module can also be used to cooperate with CTR to be configured in the intermittent state, and the driving signals for driving the first switch tube Q1 and the third switch tube Q3 are generated as turn-off signals, and the driving signals for driving the second switch tube Q2 and the fourth switch tube Q4 are generated as turn-on signals. When exiting the intermittent state, when CTR counts to 0, the wave transmission mode is switched according to the comparison value, such as Fig. 9 shown.

[0094] In the embodiment of the present application, in the non-intermittent state, the drive AQ module of the first switch tube Q1 and the fourth switch tube Q4 can be configured by enabling the shadow register at the zero-crossing moment of the next cycle, that is, when CTR=0 in the next cycle, the drive signal of the first switch tube Q1 and the drive signal of the fourth switch tube Q4 are controlled to be high level, and the drive signal of the second switch tube Q2 and the drive signal of the third switch tube Q3 are controlled to be low level. When CTR=CMP1, the drive signal of the first switch tube Q1 and the drive signal of the fourth switch tube Q4 are controlled to be low level. The signal switches to a low level. When CTR=CMP2, the drive signal of the second switch tube Q2 and the drive signal of the third switch tube Q3 are switched to a high level. When CTR=PRD time, CTR starts to count down. When CTR=CMP2, the drive signal of the second switch tube Q2 and the drive signal of the third switch tube Q3 are switched to a low level. When CTR=CMP1, the drive signal of the first switch tube Q1 and the drive signal of the fourth switch tube Q4 are switched to a high level. When CTR=0, the cycle ends.

[0095] In another embodiment, in the non-intermittent state, the first switch tube Q1 and the second switch tube Q2 can be configured to drive AQ at the CTR=PRD moment of the next cycle by enabling the shadow register, and the third switch tube Q3 and the fourth switch tube Q4 can be controlled to drive AQ at the CTR=0 moment of the next cycle. Fig.10In the non-intermittent state, when CTR=CMP1, only the drive signal of the fourth switch tube Q4 is switched to a low level, when CTR=CMP2, only the drive signal of the third switch tube Q3 is switched to a high level, at the moment CTR=PRD, the shadow register is enabled to configure the drive signals of the first switch tube Q1 and the second switch tube Q2, when CTR=CMP2, the drive signals of the second switch tube Q2 and the third switch tube Q3 are switched to a low level, when CTR=CMP1, the drive signals of the first switch tube Q1 and the fourth switch tube Q4 are switched to a high level, and when CTR=0, the cycle ends.

[0096] In the embodiment of the present application, the wave generation mode in the intermittent state ensures that when both the positive and negative flow paths of the free resonant current of the resonant tank realize the reduction of the Vds of the two lower tubes of the bridge arms to 0V, when the intermittent state is exited, the Vds of the switch tube to be turned on has been reduced to 0V in advance, so that when switching from the intermittent state to the non-intermittent state wave generation, the ZVS (zero voltage) soft switch of the lower tube of the bridge arm is realized to reduce the loss, thereby achieving a smooth transition between the square wave mode in the intermittent state and the wave generation mode in the non-intermittent state.

[0097] Combine the following Figure 11a to Figure 11f The current flow diagram of this application is described in detail.

[0098] When the LLC resonant converter is in the intermittent state, the driving signals of the second switch tube Q2 and the fourth switch tube Q4 are effective driving signals. According to the opening conditions of the second switch tube Q2 and the fourth switch tube Q4 and the direction of the Ir self-resonant current, the working state of the LLC resonant circuit can be divided into the following: Figure 11a to Figure 11f 6 stages.

[0099] like Fig.11a As shown, the resonant current Ir flows through the second diode D2 and the fourth switch tube Q4, and returns to the anode of the second diode D2 through the second diode D2, the resonant capacitor Cr, the first resonant inductor Lr, the primary coil of the transformer T and the fourth switch tube Q4.

[0100] like Fig.11b As shown, through the freewheeling of the second switch tube Q2 and the fourth switch tube Q4, the resonant current Ir passes through the second switch tube Q2, the resonant capacitor Cr, the first resonant inductor Lr, the primary coil of the transformer T and the fourth switch tube Q4, and returns to the first end of the second switch tube Q2.

[0101] like Fig.11c As shown, the resonant current Ir flows from the negative electrode of the input end through the second switch tube Q2, the resonant capacitor Cr, the first resonant inductor Lr, the primary coil of the transformer T and the third diode D3, and returns to the positive electrode of the input end.

[0102] like Fig.11d As shown, the resonant current Ir returns to the second end of the second switch tube Q2 through the second switch tube Q2, the fourth diode D4, the primary coil of the transformer T, the first resonant inductor Lr and the resonant capacitor Cr through the second switch tube Q2 and the fourth diode D4.

[0103] like Fig.11e As shown, through the freewheeling of the second switch tube Q2 and the fourth switch tube Q4, the resonant current Ir passes through the second switch tube Q2, the fourth switch tube Q4, the primary coil of the transformer T, the first resonant inductor Lr and the resonant capacitor Cr, and returns to the second end of the second switch tube Q2.

[0104] like Fig.11f As shown, the resonant current Ir flows out from the negative electrode of the input end through the first diode D1 and the fourth switch tube Q4, passes through the fourth switch tube Q4, the primary coil of the transformer T, the first resonant inductor Lr, the resonant capacitor Cr and the first diode D1, and returns to the positive electrode of the input end.

[0105] from Figure 11a to Figure 11f It can be seen that Figure 11a to Figure 11c The resonant current Ir in is the forward current, Figure 11e to Figure 11f The resonant current Ir in is a negative current.

[0106] Combination Figure 11a to Figure 11f It can be seen that during intermittent operation, that is, the intermittent state, the amplitude of the resonant current Ir can be quickly attenuated, so that the zero voltage turn-on of the fourth switch tube Q4 can be achieved when exiting the intermittent state (switching from the intermittent state to the non-intermittent state), that is, Vds is 0. After switching to the non-intermittent state, the fourth switch tube Q4 will not be suddenly turned on hard, resulting in the previous large dv / dt problem.

[0107] If the direction of the resonant current Ir is positive in the previous stage before switching, after the first switch tube Q1 and the fourth switch tube Q4 are turned on, the resonant current Ir becomes positive and increases; if the direction of the resonant current Ir is negative in the previous stage before switching, after the first switch tube Q1 and the fourth switch tube Q4 are turned on, the resonant current Ir first flows through the first diode D1 and the fourth switch tube Q4, and decreases in the reverse direction. After crossing the zero point, the current flowing through the first switch tube Q1 and the fourth switch tube Q4 becomes positive and increases, and then enters the normal wave transmission logic.

[0108] Case 2: The switch tubes to be driven first are preset to be the lower tube of the leading bridge arm and the upper tube of the lagging bridge arm, that is, the second switch tube Q2 and the third switch tube Q3.

[0109] In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned on and the lower tube is turned off. In the next cycle, after it is determined that the LLC resonant converter switches from an intermittent state to a non-intermittent state, a drive signal for controlling the lower tube of the leading bridge arm and the upper tube of the lagging bridge arm is generated according to the first comparison value, and a drive signal for controlling the upper tube of the leading bridge arm and the upper tube of the lagging bridge arm is generated according to the second comparison value.

[0110] For example, Figure 1 For the resonant converter shown, if the switch tubes to be driven first are pre-set to be the second switch tube Q2 and the third switch tube Q3, in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first switch tube Q1 and the third switch tube Q3 are controlled to be turned on, and the second switch tube Q2 and the fourth switch tube Q4 are controlled to be turned off. In the next cycle, after it is determined that the LLC resonant converter switches from the intermittent state to the non-intermittent state, a drive signal for controlling the second switch tube Q2 and the fourth switch tube Q4 is generated according to the first comparison value CMP1, and a drive signal for controlling the first switch tube Q1 and the third switch tube Q3 is generated according to the second comparison value CMP2.

[0111] like Fig.12 FIG. 1 is a schematic diagram of another driving waveform provided by an embodiment of the present application. Fig.12 It can be seen that the driving waveforms of the first switch tube Q1 and the second switch tube Q2 are complementary, and the driving waveforms of the third switch tube Q3 and the fourth switch tube Q4 are complementary. At the end of the previous cycle, the driving signals of the first switch tube Q1 and the fourth switch tube Q4 are low level, and the driving signals of the second switch tube Q2 and the third switch tube Q3 are high level. CTR=0. At this time, CTR restarts counting. When CTR counts up to CMP1, the driving signal of the third switch tube Q3 is switched from high level to low level, and the driving signal of the fourth switch tube Q4 is switched from low level to high level. When CTR counts up to CMP2, the driving signal of the first switch tube Q1 is switched from low level to high level, and the driving signal of the second switch tube Q2 and the third switch tube Q3 is switched from low level to high level. The driving signal of the second switch tube Q2 is switched from a high level to a low level. When CTR=PRD, CTR starts to decrease. When CTR counts down to CMP2, the driving signal of the third switch tube Q3 is triggered to switch from a high level to a low level, and the driving signal of the first switch tube Q1 is triggered to switch from a high level to a low level. When CTR counts down to CMP1, the driving signal of the third switch tube Q3 is triggered to switch from a low level to a high level, and the driving signal of the fourth switch tube Q4 is triggered to switch from a high level to a low level. When CTR counts down to 0, the cycle ends.

[0112] In the specific implementation, Fig.13 As shown, it is a schematic diagram of another driving change of the exit intermittent moment provided by the embodiment of the present application, from Fig.13 It can be seen that in the intermittent state, the first switch tube Q1 and the third switch tube Q3 are turned on, and the second switch tube Q2 and the fourth switch tube Q4 are turned off. When it is necessary to exit the intermittent state, that is, when switching from the intermittent state to the non-intermittent state, the CMP value updates the register at the zero crossing point. The first group of drives issued after the update, that is, the first group of drives issued at the switching moment, are the drives of the second switch tube Q2 and the third switch tube Q3. The timing starts from the switching moment. When CTR counts up to the first comparison value CMP1, the second switch tube Q2 and the third switch tube Q3 will be driven. 3 is converted to a low level. When CTR counts upward to the second comparison value CMP2, the driving signals driving the first switch tube Q1 and the fourth switch tube Q4 are converted to a high level. After counting to PRD, CTR starts to decrease. When CTR counts downward to the second comparison value CMP2, the driving signals driving the first switch tube Q1 and the fourth switch tube Q4 are converted to a low level. When CTR counts downward to the first comparison value CMP1, the driving signals driving the second switch tube Q2 and the third switch tube Q3 are converted to a high level.

[0113] from Fig.12 and Fig.13 It can be seen that in the embodiment of the present application, in the intermittent state, the Fig.12 The driving waveform shown drives the switch tube. It should be noted that: Fig.13 Although the driving signal of the fourth switch tube Q4 is at a high level for a period of time in the intermittent state, since the period is shorter than the dead zone period, the driving signal cannot actually be issued, that is, the level change within the period can be ignored.

[0114] Fig.12 and Fig.13 In the intermittent state, the driving signal of the first switch tube Q1 and the driving signal of the third switch tube Q3 are controlled to be on signals according to the value of the CMP register, and the driving signal of the second switch tube Q2 and the fourth switch tube Q4 are controlled to be off signals, that is, the first switch tube Q1 and the third switch tube Q3 are controlled to be on, and the second switch tube Q2 and the fourth switch tube Q4 are controlled to be off.

[0115] In another embodiment, in the intermittent state, the AQ module can also be used to cooperate with the CTR to be configured in the intermittent state, and the driving signals for driving the second switch tube Q2 and the fourth switch tube Q4 are generated as the off signals, and the driving signals for driving the first switch tube Q1 and the third switch tube Q3 are generated as the on signals. When exiting the intermittent state, when the CTR counts to 0, the wave transmission mode is switched according to the comparison value, such as Fig.14 shown.

[0116] In the embodiment of the present application, in the non-intermittent state, the drive AQ module of the second switch tube Q2 and the third switch tube Q3 can be configured by enabling the shadow register at the zero-crossing moment of the next cycle, that is, when CTR=0 in the next cycle, the drive signal of the second switch tube Q2 and the drive signal of the third switch tube Q3 are controlled to be high level, and the drive signal of the first switch tube Q1 and the drive signal of the fourth switch tube Q4 are controlled to be low level. When CTR counts up to CMP1, the drive signal of the second switch tube Q2 and the drive signal of the third switch tube Q3 are controlled to switch to When CTR counts up to CMP2, the drive signal of the first switch tube Q1 and the drive signal of the fourth switch tube Q4 are switched to a high level. When CTR=PRD, CTR starts to decrease. When CTR counts down to CMP2, the drive signal of the first switch tube Q1 and the drive signal of the fourth switch tube Q4 are switched to a low level. When CTR counts down to CMP1, the drive signal of the second switch tube Q2 and the drive signal of the third switch tube Q3 are switched to a high level. When CTR counts down to 0, the cycle ends.

[0117] In another embodiment, in the non-intermittent state, the third switch tube Q3 and the fourth switch tube Q4 can also be configured to drive AQ at the CTR=PRD moment of the next cycle by enabling the shadow register, and the first switch tube Q1 and the second switch tube Q2 can be controlled to drive AQ at the CTR=0 moment of the next cycle. Fig.15 In the non-intermittent state, when CTR=CMP1, only the drive signal of the second switch tube Q2 is switched to a low level, when CTR=CMP2, only the drive signal of the first switch tube Q1 is switched to a high level, at the moment of CTR=PRD, the shadow register is enabled to configure the drive signals of the third switch tube Q3 and the fourth switch tube Q4, when CTR=CMP2, the drive signals of the first switch tube Q1 and the fourth switch tube Q4 are switched to a low level, when CTR=CMP1, the drive signals of the second switch tube Q2 and the third switch tube Q3 are switched to a high level, and when CTR=0, the cycle ends.

[0118] In the embodiment of the present application, when exiting the intermittent state, the switching transition process between the wave generation mode in the intermittent state and the wave generation mode in the non-intermittent state is realized with a smooth transition.

[0119] The above is Figure 1 The control of the switch tube in the LLC resonant converter circuit shown in FIG. Figure 2 The control of the switch tube in the LLC resonant conversion circuit in the LLC resonant converter shown is briefly explained.

[0120] like Fig.16As shown, in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the upper tube (fifth switch tube Q7) of the LLC resonant conversion circuit is controlled to be turned off, and the lower tube (sixth switch tube Q8) of the LLC resonant conversion circuit is controlled to be turned on. In the next cycle, when it is determined that the LLC resonant converter is in a non-intermittent state, the fifth switch tube Q7 and the sixth switch tube Q8 are controlled to be turned on or off according to the comparison value. Specifically, when CTR counts up, if CTR counts up to CMP1, the fifth switch tube Q7 is controlled to be turned off, and the sixth switch tube Q8 is controlled to be turned on. When CTR counts down, if CTR counts down to CMP1, the fifth switch tube Q7 is controlled to be turned on, and the sixth switch tube Q8 is controlled to be turned off.

[0121] right Figure 2 Other control methods of the switch tube in the LLC resonant converter in the LLC resonant conversion circuit can refer to the above Figure 1 The description of the control of the switch tube in the LLC resonant conversion circuit in the LLC resonant converter shown will not be repeated any more.

[0122] Based on the same inventive concept, an embodiment of the present application also provides a control device for an LLC resonant converter. The principle of solving the technical problem by the device is similar to the principle of the LLC resonant converter control method provided above, and the repeated parts will not be repeated.

[0123] like Fig.17 As shown, a control device for an LLC resonant converter provided in an embodiment of the present application includes:

[0124] The first control module 1301 is used for, in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, controlling the upper tube in the LLC resonant conversion circuit to turn off, controlling the lower tube in the LLC resonant conversion circuit to turn on, or controlling the upper tube to turn on, controlling the lower tube to turn off according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state;

[0125] The second control module 1302 is used to control the opening or closing of the upper tube and the lower tube according to the first comparison value and the second comparison value after determining in the next cycle that the LLC resonant converter switches from the intermittent state to the non-intermittent state, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a periodic value.

[0126] In one embodiment, the second control module 1302 is further configured to:

[0127] In the next cycle, the start time of the next cycle and the half cycle time of the next cycle are used as the switching time for controlling the opening or closing of the upper tube and the lower tube.

[0128] In one embodiment, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0129] The first control module 1301 is specifically used for:

[0130] If the switching tubes that are preferentially controlled to be turned on are the first upper tube and the first lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned off, and the first lower tube and the second lower tube are controlled to be turned on.

[0131] In one embodiment, the second control module 1302 is specifically configured to:

[0132] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the second lower tube to be turned off according to the first comparison value, and controlling the second upper tube to be turned on according to the second comparison value;

[0133] The half period of the next period is used as the switching period, the first lower tube is controlled to be turned off according to the second comparison value, and the first upper tube is controlled to be turned on according to the first comparison value.

[0134] In one embodiment, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0135] The first control module 1301 is specifically used for:

[0136] If the switching tubes that are preferentially controlled to be turned on are the second upper tube and the second lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned on, and the first lower tube and the second lower tube are controlled to be turned off.

[0137] In one embodiment, the second control module 1302 is specifically configured to:

[0138] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the first lower tube to be turned off according to the first comparison value, and controlling the first upper tube to be turned on according to the second comparison value;

[0139] The half period of the next period is used as the switching period, the second lower tube is controlled to be turned off according to the second comparison value, and the second upper tube is controlled to be turned on according to the first comparison value.

[0140] Based on the same inventive concept, an embodiment of the present application also provides a control device for an LLC resonant converter. The principle of the device for solving the technical problem is similar to the principle of the LLC resonant converter control method provided above, and the repeated parts will not be repeated.

[0141] like Fig.18 As shown, it is a structural schematic diagram of a control device of an LLC resonant converter provided in an embodiment of the present application, including a memory 1401, a processor 1402, and a computer program stored in the memory 1401 and executable on the processor 1402. When the processor 1402 executes the computer program, the following steps are implemented:

[0142] In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off;

[0143] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube and the lower tube are controlled to be turned on or off according to the first comparison value and the second comparison value, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a cycle value.

[0144] In one embodiment, the processor 1402 is further configured to:

[0145] In the next cycle, the start time of the next cycle and the half cycle time of the next cycle are used as the switching time for controlling the opening or closing of the upper tube and the lower tube.

[0146] In one embodiment, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0147] The processor 1402 is specifically configured to:

[0148] If the switching tubes that are preferentially controlled to be turned on are the first upper tube and the first lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned off, and the first lower tube and the second lower tube are controlled to be turned on.

[0149] In one embodiment, the processor 1402 is specifically configured to:

[0150] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the second lower tube to be turned off according to the first comparison value, and controlling the second upper tube to be turned on according to the second comparison value;

[0151] The half period of the next period is used as the switching period, the first lower tube is controlled to be turned off according to the second comparison value, and the first upper tube is controlled to be turned on according to the first comparison value.

[0152] In one embodiment, the LLC resonant conversion circuit includes a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series;

[0153] The processor 1402 is specifically configured to:

[0154] If the switching tubes that are preferentially controlled to be turned on are the second upper tube and the second lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned on, and the first lower tube and the second lower tube are controlled to be turned off.

[0155] In one embodiment, the processor 1402 is specifically configured to:

[0156] In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the first lower tube to be turned off according to the first comparison value, and controlling the first upper tube to be turned on according to the second comparison value;

[0157] The half period of the next period is used as the switching period, the second lower tube is controlled to be turned off according to the second comparison value, and the second upper tube is controlled to be turned on according to the first comparison value.

[0158] Based on the same inventive concept, an embodiment of the present application also provides an LLC resonant converter. The principle of the LLC resonant converter for solving the technical problem is similar to the principle of the LLC resonant converter control method provided above, and the repeated parts will not be repeated.

[0159] An LLC resonant converter provided in an embodiment of the present application includes an LLC resonant conversion circuit and a control device of the LLC resonant converter as described in any one of the above.

[0160] Specifically, the LLC resonant conversion circuit can refer to Figure 1 and Figure 2 The resonant conversion circuit disclosed in will not be repeated here.

[0161] The embodiments of the present application provide an LLC resonant converter control method, apparatus, device and LLC resonant converter. In the current cycle, after determining that the LLC resonant converter is in an intermittent state, the switching tube that is turned on is preferentially controlled when the LLC resonant converter switches from an intermittent state to a non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, and the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off. In the next cycle, after determining that the LLC resonant converter switches from an intermittent state to a non-intermittent state, the upper tube and the lower tube are controlled to be turned on or off according to a first comparison value and a second comparison value, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is the cycle value. When the LLC resonant converter is in an intermittent state, the upper tube is controlled to be turned off and the lower tube is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off, so as to realize soft turning on of the tube connected to the transformer, so that the resonant current flows through the turned-on switch tube, the resonant inductor, the resonant capacitor and the primary side of the transformer in the intermittent state, thereby attenuating the amplitude of the resonant current, reducing the large di / dt and dv / dt caused by the hard turning on of the primary side switch tube, reducing the amplitude of the coupling current, reducing the loss of the switch tube, reducing the voltage overcharge coupled to the secondary side, and when the LLC resonant converter exits the intermittent state, the Vds of the tube to be turned on is reduced to 0V in advance, reducing the probability of excessive voltage stress of the SR MOS tube, thereby reducing the probability of damage to the MOS tube, and improving the performance of the LLC resonant converter.

[0162] The present application is described above with reference to the block diagrams and / or flow charts showing the methods, devices (systems) and / or computer program products according to the embodiments of the present application. It should be understood that a block of the block diagram and / or flow chart diagram and a combination of blocks of the block diagram and / or flow chart diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer and / or other programmable data processing device to produce a machine, so that the instructions executed by the computer processor and / or other programmable data processing device create a method for implementing the functions / actions specified in the block diagram and / or flow chart block.

[0163] Accordingly, the present application may also be implemented with hardware and / or software (including firmware, resident software, microcode, etc.). Furthermore, the present application may take the form of a computer program product on a computer-usable or computer-readable storage medium, which has a computer-usable or computer-readable program code implemented in the medium, for use by an instruction execution system or in conjunction with an instruction execution system. In the context of the present application, a computer-usable or computer-readable medium may be any medium that may contain, store, communicate, transmit, or convey a program for use by an instruction execution system, device, or apparatus, or in conjunction with an instruction execution system, device, or apparatus.

[0164] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A LLC resonant converter control method, characterized in that: The LLC resonant converter includes an LLC resonant conversion circuit, and the method includes: In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off; In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube and the lower tube are controlled to be turned on or off according to the first comparison value and the second comparison value, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a cycle value.

2. The method according to claim 1, characterized in that The method further includes: In the next cycle, the start time of the next cycle and the half cycle time of the next cycle are used as the switching time for controlling the opening or closing of the upper tube and the lower tube.

3. The method according to claim 2, characterized in that The LLC resonant conversion circuit comprises a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series; In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off, including: If the switching tubes that are preferentially controlled to be turned on are the first upper tube and the first lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned off, and the first lower tube and the second lower tube are controlled to be turned on.

4. The method according to claim 3, characterized in that In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, controlling the upper tube and the lower tube to be turned on or off according to the first comparison value and the second comparison value, comprises: In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the second lower tube to be turned off according to the first comparison value, and controlling the second upper tube to be turned on according to the second comparison value; The half period of the next period is used as the switching period, the first lower tube is controlled to be turned off according to the second comparison value, and the first upper tube is controlled to be turned on according to the first comparison value.

5. The method according to claim 2, characterized in that The LLC resonant conversion circuit comprises a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series; In the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from the intermittent state to the non-intermittent state, the upper tube in the LLC resonant conversion circuit is controlled to be turned off, the lower tube in the LLC resonant conversion circuit is controlled to be turned on, or the upper tube is controlled to be turned on and the lower tube is controlled to be turned off, including: If the switching tubes that are preferentially controlled to be turned on are the second upper tube and the second lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned on, and the first lower tube and the second lower tube are controlled to be turned off.

6. The method according to claim 5, characterized in that In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, controlling the upper tube and the lower tube to be turned on or off according to the first comparison value and the second comparison value, comprises: In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the first lower tube to be turned off according to the first comparison value, and controlling the first upper tube to be turned on according to the second comparison value; The half period of the next period is used as the switching period, the second lower tube is controlled to be turned off according to the second comparison value, and the second upper tube is controlled to be turned on according to the first comparison value.

7. A control device for an LLC resonant converter, characterized in that: include: A first control module is used for, in the current cycle, when it is determined that the LLC resonant converter switches from an intermittent state to an intermittent state, controlling the upper tube in the LLC resonant conversion circuit to turn off, controlling the lower tube in the LLC resonant conversion circuit to turn on, or controlling the upper tube to turn on, controlling the lower tube to turn off according to the switch tube that is preferentially controlled to be turned on when the LLC resonant converter switches from an intermittent state to a non-intermittent state; The second control module is used to control the opening or closing of the upper tube and the lower tube according to the first comparison value and the second comparison value after determining in the next cycle that the LLC resonant converter switches from the intermittent state to the non-intermittent state, wherein the first comparison value is less than the second comparison value, and the sum of the first comparison value and the second comparison value is a periodic value.

8. The device according to claim 7, characterized in that The second control module is also used for: In the next cycle, the start time of the next cycle and the half cycle time of the next cycle are used as the switching time for controlling the opening or closing of the upper tube and the lower tube.

9. The device according to claim 8, characterized in that The LLC resonant conversion circuit comprises a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series; The first control module is specifically used for: If the switching tubes that are preferentially controlled to be turned on are the first upper tube and the first lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned off, and the first lower tube and the second lower tube are controlled to be turned on.

10. The device according to claim 9, characterized in that The second control module is specifically used for: In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the second lower tube to be turned off according to the first comparison value, and controlling the second upper tube to be turned on according to the second comparison value; The half period of the next period is used as the switching period, the first lower tube is controlled to be turned off according to the second comparison value, and the first upper tube is controlled to be turned on according to the first comparison value.

11. The device according to claim 8, characterized in that The LLC resonant conversion circuit comprises a first bridge arm formed by a first upper tube and a first lower tube connected in series, and a second bridge arm formed by a second upper tube and a second lower tube connected in series; The first control module is specifically used for: If the switching tubes that are preferentially controlled to be turned on are the second upper tube and the second lower tube when the LLC resonant converter switches from an intermittent state to a non-intermittent state, then in the current cycle, when it is determined that the LLC resonant converter is in an intermittent state, the first upper tube and the second upper tube are controlled to be turned on, and the first lower tube and the second lower tube are controlled to be turned off.

12. The device according to claim 11, characterized in that The second control module is specifically used for: In the next cycle, after determining that the LLC resonant converter switches from the intermittent state to the non-intermittent state, taking the start time of the next cycle as the switching time, controlling the first lower tube to be turned off according to the first comparison value, and controlling the first upper tube to be turned on according to the second comparison value; The half period of the next period is used as the switching period, the second lower tube is controlled to be turned off according to the second comparison value, and the second upper tube is controlled to be turned on according to the first comparison value.

13. A control device for an LLC resonant converter, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of claims 1 to 6 when executing the computer program.

14. An LLC resonant converter, characterized in that: The invention comprises an LLC resonant converter circuit and a control device of the LLC resonant converter as claimed in claim 13.

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