Tandem wide-range LLC resonant converter topological structure

Abstract

The utility model belongs to the technical field of power electronic converters, and discloses a series connection type wide-range LLC resonant converter topological structure, a Buck circuit comprises a bridge arm, a full-bridge LLC circuit comprises two bridge arms, a half-bridge LLC circuit comprises two bridge arms, the half-bridge LLC circuit and the full-bridge LLC circuit share one bridge arm, and the half-bridge LLC circuit and the full-bridge LLC circuit share one bridge arm. And the full-bridge LLC circuit or the half-bridge LLC circuit of the converter is controlled to work by controlling the on and off of the non-shared bridge arm. The first MOS tube, the second MOS tube, the third MOS tube, the fourth MOS tube, the fifth MOS tube and the sixth MOS tube can be turned on in a zero-voltage mode, the Buck circuit only bears a part of load power, and the efficiency of the converter is high. According to the utility model, wide-range input can be realized, and the gain range of the converter is expanded. And meanwhile, the Buck circuit only bears a part of load power, so that the efficiency of the converter is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of power electronic converters, and particularly relates to a series-type wide-range LLC resonant converter topology structure. Background Art

[0002] With the rapid development of the new energy field, higher requirements are put forward for isolated DC / DC converters, which need to have the ability to operate efficiently and work within a wider voltage gain range. The two-stage DC / DC converter has a wide voltage regulation range, but its operating efficiency is low. The LLC converter has a simple structure and high conversion efficiency, but its gain range is narrow.

[0003] The Chinese patent publication number is CN115360924A, and the patent application named "A Switching Multiplexing Converter Topology Structure and Its Modulation Method" provides a switching multiplexing converter topology structure and its modulation method. The topology structure includes: a power supply end, a switching multiplexing Buck converter, a switching multiplexing LC resonant converter, and a load end; the switching multiplexing Buck converter includes a first switching tube, a second switching tube, a first inductor, and a first capacitor; the switching multiplexing LC resonant converter includes a first capacitor, a first switching loop, a second switching loop, and a resonant cavity; the first switching loop includes a first switching tube, a second switching tube, a third switching tube, and a fourth switching tube; the modulation method includes: defining the ratio of the conduction time of the second switching tube and the third switching tube to the switching period of the switching multiplexing converter as the duty cycle; adjusting the voltage across the capacitor by adjusting the duty cycle to change the voltage amplitude between the midpoints of the first bridge arm and the second bridge arm, so as to adjust the voltage gain of the switching multiplexing converter. However, the switching tubes of this patent application cannot achieve zero-voltage turn-on, and the conversion efficiency is not high. Summary of the Utility Model

[0004] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present utility model is to provide a series-type wide-range LLC resonant converter topology structure, so as to improve the conversion efficiency and wide gain range of the LLC resonant converter topology structure.

[0005] To achieve the above purpose, the technical solution adopted by the present utility model is:

[0006] A series-type wide-range LLC resonant converter topology structure includes: an input power supply V in , a first MOS transistor S 1 , a second MOS transistor S 2 , a third MOS transistor S 3 , a fourth MOS transistor S 4 , a fifth MOS transistor S 5 , a sixth MOS transistor S 6 , a seventh MOS transistor SB1 , the eighth MOS transistor S B2 , the first inductor L B , the first capacitor C 1 , the second capacitor C 2 , the resonant capacitor C r , the exciting inductor L m , the transformer T, the first diode D 1 , the second diode D 2 , the third diode D 3 , the fourth diode D 4 , the third capacitor C O and the output terminal; the drain of the seventh MOS transistor S B1 , the drain of the first MOS transistor S 1 is connected to the positive pole of the input power supply V in ; the source of the eighth MOS transistor S B2 , the source of the second MOS transistor S 2 , the source of the fourth MOS transistor S 4 are connected to the negative pole of the input power supply V in ; the drain of the eighth MOS transistor S B2 is connected to the source of the seventh MOS transistor S B1 , the drain of the second MOS transistor S 2 is connected to the source of the first MOS transistor S 1 , the drain of the fourth MOS transistor S 4 , the drain of the sixth MOS transistor S 6 is connected to the source of the third MOS transistor S 3 , the source of the fifth MOS transistor S 5 is connected to the source of the sixth MOS transistor S 6 ; the first end of the first inductor L B is connected to the source of the seventh MOS transistor S B1 , and the second end is connected to the positive pole of the first capacitor C 1 ; the negative pole of the second capacitor C 2 is connected to the negative pole of the input power supply V in ; the positive pole of the first capacitor C 1 , the drain of the third MOS transistor S 3 are connected to the second end of the first inductor L B , the negative pole of the first capacitor C 1 , the drain of the fifth MOS transistor S 5 are connected to the positive pole of the second capacitor C 2 ; one end of the resonant inductor Lr is connected to the source of the third MOS transistor S 3 , and the other end is connected to the same-named end of the primary side of the transformer T; one end of the resonant capacitor C r is connected to the source of the first MOS transistor S 1is connected to the source electrode, and the other end is connected to the opposite-named terminal of the primary side of the transformer T; the exciting inductor L m is connected in parallel with the primary side of the transformer T; the anode of the first diode D 1 , the cathode of the second diode D 2 are connected to the same-named terminal of the secondary side of the transformer T, and the anode of the third diode D 3 , the cathode of the fourth diode D 4 are connected to the opposite-named terminal of the secondary side of the transformer T; the cathode of the first diode D 1 , the cathode of the third diode D 3 , the positive electrode of the third capacitor C O are connected to the positive electrode of the output terminal, and the anode of the second diode D 2 , the anode of the fourth diode D 4 , the negative electrode of the third capacitor C O are connected to the negative electrode of the output terminal.

[0007] Optionally, a diode and a capacitor are connected between the source and drain of the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 and the sixth MOS transistor S 6 . The anode of each diode is respectively connected to the source of the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 and the sixth MOS transistor, and the cathode of each diode is respectively connected to the drain of the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 and the sixth MOS transistor.

[0008] Specifically, the capacitance values of the first capacitor C 1 and the second capacitor C 2 are equal, and the output voltage of the Buck circuit is evenly distributed.

[0009] Optionally, the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5and the sixth MOS transistor S 6 Both adopt chips integrated with drive circuits and protection circuits.

[0010] Optionally, the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 and the sixth MOS transistor S 6 All adopt gallium nitride power chips.

[0011] Optionally, the transformer T is a dual-winding transformer.

[0012] Optionally, it further includes a fourth capacitor C B , the positive electrode of the fourth capacitor C B is connected to the second end of the first inductor L B , and the negative electrode is connected to the negative electrode of the input power supply V in .

[0013] Optionally, the primary side of the transformer T is wound with Litz wire, and the secondary side is wound with copper foil.

[0014] Optionally, the resonant inductor Lr is wound with Litz wire.

[0015] Optionally, the capacitance values of the first capacitor C 1 and the second capacitor C 2 are equal.

[0016] Compared with the prior art, the present utility model has the following beneficial effects:

[0017] The present utility model provides a series-type wide-range LLC resonant converter topology structure. The first MOS transistor, the second MOS transistor, the third MOS transistor, the fourth MOS transistor, the fifth MOS transistor, and the sixth MOS transistor of the present utility model can all be turned on with zero voltage, and the Buck circuit only undertakes a part of the load power, so the converter has high efficiency. The present utility model can achieve wide-range input and expand the gain range of the converter. At the same time, the Buck circuit only undertakes a part of the load power, which improves the efficiency of the converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are only for explanatory purposes and are not intended to limit the scope of the disclosure of the present utility model in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to help understand the present utility model, rather than specifically limiting the shapes and proportional dimensions of the components of the present utility model. In the drawings:

[0019] Figure 1It is the topological structure diagram of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0020] Figure 2 It is the timing diagram of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0021] Figure 3 It is the first topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0022] Figure 4 It is the second topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0023] Figure 5 It is the third topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0024] Figure 6 It is the fourth topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0025] Figure 7 It is the fifth topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0026] Figure 8 It is the sixth topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0027] Figure 9 It is the seventh topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0028] Figure 10 It is the eighth topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0029] Figure 11 It is the ninth topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model;

[0030] Figure 12 It is the tenth topological mode of a series-type wide-range LLC resonant converter in the embodiment of the present utility model. Specific implementation manner

[0031] In order to enable those skilled in the art to better understand the technical solutions in the present utility model, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0032] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only embodiments.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs. The terms used in the description of the present utility model herein are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0034] The following will describe the present utility model in detail with reference to the accompanying drawings.

[0035] As Figure 1 shown, a series-type wide-range LLC resonant converter topology structure of the present utility model includes: an input power supply V in , a Buck circuit, a full-bridge LLC circuit, a half-bridge LLC circuit, and a load resistor RL.

[0036] The bridge arm of the Buck circuit is directly connected to the input power supply V in ; the first capacitor C 1 and the second capacitor C 2 are connected in series to evenly distribute the output voltage of the Buck circuit. The first bridge arm of the primary side of the LLC circuit is connected in series with the output end of the Buck circuit. The fifth MOS transistor S 5 and the sixth MOS transistor S 6 are connected in reverse series and then connected between the Buck circuit and the LLC circuit. The second bridge arm of the primary side of the LLC circuit is directly connected to the input power supply V in . The two ends of the third capacitor C O are the output ends of the converter topology structure.

[0037] The Buck circuit includes the seventh MOS transistor S B1 , the eighth MOS transistor S B2 , the first inductor L B and the fourth capacitor C B . The full-bridge LLC circuit includes the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the resonant inductor Lr, the resonant capacitor C r , the exciting inductor L m , the transformer T, the first diode D 1 , the second diode D 2 , the third diode D 3 , the fourth diode D 4 and the third capacitor C O . Among them, the transformer T is a dual-winding transformer.

[0038] The bridge arms shared by the full-bridge LLC circuit and the half-bridge LLC circuit include the first MOS transistor S 1 and the second MOS transistor S 2 .

[0039] The half-bridge LLC circuit includes the first MOS transistor S 1 , the second MOS transistor S 2 , the fifth MOS transistor S 5 , the sixth MOS transistor S 6 , the resonant inductor Lr, the resonant capacitor C r , the exciting inductor L m , the transformer T, the first diode D 1 , the second diode D 2 , the third diode D 3 , the fourth diode D 4 and the third capacitor C O .

[0040] The drain of the seventh MOS transistor S B1 , the drain of the first MOS transistor S 1 are connected to the positive pole of the input power supply V in ; the source of the eighth MOS transistor S B2 , the source of the second MOS transistor S 2 , the source of the fourth MOS transistor S 4 are connected to the negative pole of the input power supply; the drain of the eighth MOS transistor S B2 is connected to the source of the seventh MOS transistor S B1 , the drain of the second MOS transistor S 2 is connected to the source of the first MOS transistor S 1 , the fourth MOS transistor S4 The drain of the sixth MOS transistor S 6 The drain of the third MOS transistor S 3 is connected to the source of the fifth MOS transistor S 5 The source of the fifth MOS transistor S 6 is connected to the source of the sixth MOS transistor S B One end of the first inductor L B1 is connected to the source of the seventh MOS transistor S 1 and the other end is connected to the positive electrode of the first capacitor C 2 The negative electrode of the second capacitor C in is connected to the negative electrode of the input power supply V 3 The drain of the third MOS transistor S 1 is connected to the positive electrode of the first capacitor C 1 The negative electrode of the first capacitor C 5 The drain of the fifth MOS transistor S 2 is connected to the positive electrode of the second capacitor C 3 One end of the resonant inductor Lr is connected to the source of the third MOS transistor S r and the other end is connected to the same-name terminal of the primary side of the transformer T; One end of the resonant capacitor C 1 is connected to the source of the first MOS transistor S m and the other end is connected to the different-name terminal of the primary side of the transformer T; The exciting inductor L 1 is connected in parallel with the primary side of the transformer T; The anode of the first diode D 2 The cathode of the second diode D 3 is connected to the same-name terminal of the secondary side of the transformer T, The anode of the third diode D 4 The cathode of the fourth diode D 1 The cathode of the first diode D 3 The cathode of the third diode D O The positive electrode of the third capacitor C 2 is connected to the positive electrode of the output terminal, The anode of the second diode D 4 The anode of the fourth diode D O The negative electrode of the third capacitor C

[0041] The Buck circuit includes one leg, the full-bridge LLC circuit includes two legs, the half-bridge LLC circuit includes two legs, the half-bridge LLC circuit and the full-bridge LLC circuit share one leg, that is, the LLC circuit has a total of three legs, and the operation of the full-bridge LLC circuit or the half-bridge LLC circuit of the converter is controlled by controlling the conduction and turn-off of the non-shared legs.

[0042] By changing the duty cycle D of the Buck circuit 1and the duty cycle D of the first leg of the LLC circuit 2 Adjust the output voltage of the converter. The Buck circuit only undertakes a part of the load power, which can improve the efficiency of the converter.

[0043] Specifically, a diode and a capacitor are respectively connected between the source and drain of the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 , the sixth MOS transistor S 6 . The anode of the diode is connected to the source of the MOS transistor, and the cathode of the diode is connected to the drain of the MOS transistor.

[0044] The first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 , the sixth MOS transistor S 6 of the present utility model are selected as gallium nitride power chips, which integrate a drive circuit and a protection circuit inside. By controlling the conduction and cutoff of the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 , the sixth MOS transistor S 6 , control the LLC circuit to work in the full-bridge mode or the half-bridge mode.

[0045] The fifth MOS transistor S 5 , the sixth MOS transistor S 6 of the present utility model are connected in reverse series to the circuit, which can control the bidirectional flow of current.

[0046] The present utility model utilizes the second leg of the LLC circuit to work in the fixed-frequency mode, changes the duty cycle of the Buck circuit and the duty cycle of the first leg of the LLC circuit to adjust the output voltage of the converter, achieves wide-range input, and expands the gain range of the converter. At the same time, the Buck circuit only undertakes a part of the load power, improving the efficiency of the converter.

[0047] Embodiment

[0048] For a series-type wide-range LLC resonant converter topology of the present utility model, when the switching frequencies of the Buck circuit and the LLC circuit are the same, its working timing is divided into 10 time periods, as Figure 2 shown, the time is t 0 -t 10 , and the following will be gradually analyzed according to different timing diagrams respectively.

[0049] As shown Figure 1 in the figure, a diode and a capacitor are respectively connected between the source and drain of the first MOS transistor S 1 , the second MOS transistor S 2 , the third MOS transistor S 3 , the fourth MOS transistor S 4 , the fifth MOS transistor S 5 , and the sixth MOS transistor S 6 . The anode of the diode is connected to the source of the MOS transistor, and the cathode of the diode is connected to the drain of the MOS transistor.

[0050] As shown Figure 3 in the figure, in mode 1 during the time period t0 - t1: the first MOS transistor S 1 , the fourth MOS transistor S 4 , the sixth MOS transistor S 6 , and the eighth MOS transistor S B2 are turned on; the current of the Buck circuit flows from the first inductor L B to the positive electrode of the fourth capacitor C B and the positive electrode of the first capacitor C 1 , then from the negative electrode of the fourth capacitor C B and the negative electrode of C 2 to the eighth MOS transistor S B2 , and finally flows back to the first inductor L B ; the resonant inductor Lr of the LLC circuit and the resonant capacitor C r participate in resonance, the resonant current is not equal to the exciting current, and there is current flowing through the primary side of the transformer T. The current flows out from the positive electrode of the input power supply, passes through the first MOS transistor S 1 and then flows to the resonant capacitor C r , the exciting inductor L m and the opposite-named end of the primary side of the transformer T, the resonant inductor Lr, and finally flows back to the negative electrode of the input power supply V 4 after passing through the fourth MOS transistor S in ; the current on the secondary side of the transformer T flows in from the opposite-named end, passes through the third diode D 3 and then flows to the positive electrode of the third capacitor C O , the positive electrode of the load end, and finally flows back to the same-named end of the secondary side of the transformer T after passing through the second diode D 2 ; the fourth MOS transistor S 4 is turned off, and mode 1 ends.

[0051] As shown Figure 4 in the figure, in mode 2 during the time period t1 - t2: the first MOS transistor S 1 , the sixth MOS transistor S 6 , and the eighth MOS transistor S B2 are turned on, and the fourth MOS transistor S4 Turn off; the current flow in the Buck circuit remains the same as in Mode 1; the resonant current starts to charge the capacitor connected to the fourth MOS transistor S 4 ; the capacitor connected to the third MOS transistor S 3 and the capacitor connected to the fifth MOS transistor S 5 start to discharge, preparing for the zero-voltage turn-on of the fifth MOS transistor S 5 ; the current flows out from the positive pole of the input power supply, passes through the first MOS transistor S 1 and then flows to the resonant capacitor C r , the exciting inductor L m and the opposite-named terminal of the primary side of the transformer T, the resonant inductor Lr, and then charges the capacitor and finally flows back to the negative pole of the power supply; the current flow in the secondary side of the transformer T remains the same as in Mode 1; the fifth MOS transistor S 5 conducts, and Mode 2 ends.

[0052] As Figure 5 shown, in Mode 3 during the time period t2 - t3: the first MOS transistor S 1 , the fifth MOS transistor S 5 , the sixth MOS transistor S 6 , and the eighth MOS transistor S B2 conduct; the current flow in the Buck circuit remains the same as in Mode 1; the resonant current is not equal to the exciting current, and there is current flowing through the primary side of the transformer T. The current flows out from the positive pole of the input power supply, passes through the first MOS transistor S 1 and then flows to the resonant capacitor C r , the exciting inductor L m and the opposite-named terminal of the primary side of the transformer T, the resonant inductor Lr, the sixth MOS transistor S 6 , the fifth MOS transistor S 5 , and finally passes through the second capacitor C 2 and flows back to the negative pole of the input power supply; the current flow in the secondary side of the transformer T remains the same as in Mode 1; until the resonant current is equal to the exciting current, Mode 3 ends.

[0053] As Figure 6 shown, in Mode 4 during the time period t3 - t4: the conduction situation of the MOS transistors, the current flow in the Buck circuit, and the resonant current flow remain the same as in Mode 3; the resonant current is equal to the exciting current, and there is no current flowing through the transformer T. The third capacitor C O supplies power to the load; the first MOS transistor S 1 , the sixth MOS transistor S 6 turn off, and Mode 4 ends.

[0054] As Figure 7 shown, in Mode 5 during the time period t4 - t5: the fifth MOS transistor S 5 conducts, the first MOS transistor S 1 , the sixth MOS transistor S6 Turn off; the current flow in the Buck circuit remains consistent with Mode 1; the resonant current starts to charge the capacitor connected to the first MOS tube S 1 , the capacitor connected to the fourth MOS tube S 4 , the capacitor connected to the sixth MOS tube S 6 ; the capacitor connected to the second MOS tube S 2 and the capacitor connected to the third MOS tube S 3 discharge until the diode connected to the second MOS tube S 2 and the diode connected to the third MOS tube S 3 conduct, preparing for the zero-voltage turn-on of the second MOS tube S 2 and the third MOS tube S 3 ; the current on the secondary side of the transformer T flows in from the same-named terminal, passes through the first diode D 1 and then flows to the positive electrode of the third capacitor C O , the positive electrode of the load terminal, and finally passes through the fourth diode D 4 and then flows back to the same-named terminal of the secondary side of the transformer T; the second MOS tube S 2 , the third MOS tube S 3 conduct, and Mode 5 ends.

[0055] As Figure 8 shown, in Mode 6 during the time period t5 - t6: the second MOS tube S 2 , the third MOS tube S 3 , the fifth MOS tube S 5 , the seventh MOS tube S B1 conduct; the current in the Buck circuit flows out from the positive electrode of the input power supply V in , passes through the seventh MOS tube S B1 and then flows to the first inductor L B , the positive electrode of the fourth capacitor C B and the positive electrode of the first capacitor C 1 , and then flows back to the negative electrode of the output power supply from the negative electrode of the fourth capacitor C B and the negative electrode of the second capacitor C 2 ; the resonant inductor Lr of the LLC circuit and the resonant capacitor C r participate in resonance, the resonant current is not equal to the exciting current, and there is current flowing through the primary side of the transformer T. The current flows out from the positive electrode of the first capacitor C 1 , passes through the third MOS tube S 3 and then flows to the resonant inductor Lr, the exciting inductor L m and the opposite-named terminal of the primary side of the transformer T, the resonant capacitor C r , and finally passes through the second MOS tube S 2 and then flows back to the negative electrode of the second capacitor C 2 ; the current on the secondary side of the transformer T remains consistent with Mode 5; the third MOS tube S3 Turn off, end of Mode Six.

[0056] As Figure 9 shown, in Mode Seven during the time period t6 - t7: The second MOS transistor S 2 , the fifth MOS transistor S 5 , the seventh MOS transistor S B1 conduct, and the third MOS transistor S 3 turns off; The current flow in the Buck circuit remains the same as in Mode Six; The resonant current starts to charge the capacitor connected to the third MOS transistor S 3 , and the capacitors connected to the fourth MOS transistor S 4 and the sixth MOS transistor S 6 start to discharge, preparing for the zero - voltage turn - on of the sixth MOS transistor S 6 ; The current flows out from the positive electrode of the first capacitor C 1 , passes through the third MOS transistor S 3 and then flows to the resonant inductor Lr, the exciting inductor L m and the opposite - named terminal of the primary side of the transformer T, the resonant capacitor C r , and then charges the capacitor, and finally flows back to the negative terminal of the power supply; The current flow in the secondary side of the transformer T remains the same as in Mode Five; The sixth MOS transistor S 6 conducts, and Mode Seven ends.

[0057] As Figure 10 shown, in Mode Eight during the time period t7 - t8: The second MOS transistor S 2 , the fifth MOS transistor S 5 , the sixth MOS transistor S 6 conduct, and the seventh MOS transistor S B1 conducts; The current flow in the Buck circuit remains the same as in Mode Six; The resonant current and the exciting current are not equal, and there is current flowing through the primary side of the transformer T. The current flows out from the positive electrode of the second capacitor C 2 , passes through the fifth MOS transistor S 5 , the sixth MOS transistor S 6 and then flows to the resonant inductor Lr, the exciting inductor L m and the opposite - named terminal of the primary side of the transformer T, the resonant capacitor C r , and finally flows back to the negative electrode of the second capacitor C 2 ; The current flow in the secondary side of the transformer T remains the same as in Mode Five; Until the resonant current and the exciting current are equal, Mode Eight ends.

[0058] As Figure 11 shown, in Mode Nine during the time period t8 - t9: The conduction situation of the MOS transistors, the current flow in the Buck circuit, and the resonant current flow are the same as in Mode Eight; The resonant current and the exciting current are equal, and there is no current flowing through the transformer T. The third capacitor C O supplies power to the load terminal; The second MOS transistor S2 and the fifth MOS transistor S 5 is turned off, and Mode Nine ends.

[0059] As Figure 12 shown, in Mode Ten during the time period t9 - t10: the sixth MOS transistor S 6 is turned on, and the second MOS transistor S 2 and the fifth MOS transistor S 5 are turned off; the current flow direction of the Buck circuit remains the same as that in Mode Six; the resonant current starts to charge the capacitors connected to the second MOS transistor S 2 , the third MOS transistor S 3 , and the fifth MOS transistor S 5 ; the capacitors connected to the first MOS transistor S 1 and the fourth MOS transistor S 4 are discharged until the diodes connected to the first MOS transistor S 1 and the fourth MOS transistor S 4 are turned on, preparing for the zero - voltage turn - on of the first MOS transistor S 1 and the fourth MOS transistor S 4 ; the current flow direction of the secondary side of the transformer T remains the same as that in Mode One; the first MOS transistor S 1 and the fourth MOS transistor S 4 are turned on, and Mode Ten ends.

[0060] In the series - type wide - range LLC resonant converter proposed by the present utility model, the voltage across the fourth capacitor C B1 can be controlled by changing the duty cycle D 1 of S B in the Buck circuit. When the second bridge arm in the LLC circuit operates at a fixed frequency and conducts complementarily, the output voltage of the converter is controlled by controlling the conduction time of the MOS transistors in the first bridge arm of the LLC circuit. This application can achieve a wide gain range while maintaining high efficiency.

[0061] In the above embodiments, the device components involved are all conventional device components without special instructions. The structural setting methods, working methods, or control methods involved are all conventional setting methods, working methods, or control methods in the art without special instructions.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model and are not intended to limit them. Other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present utility model should be covered within the scope of the claims of the present utility model as long as they do not depart from the spirit and scope of the technical solutions of the present utility model.

Claims

1. A series wide-range LLC resonant converter topology, characterized in that: include: Input power V in , resonant inductor Lr, first MOS tube S1, second MOS tube S2, third MOS tube S3, fourth MOS tube S4, fifth MOS tube S5, sixth MOS tube S6, seventh MOS tube S B1 、The eighth MOS tube S B2 , the first inductor L B , first capacitor C1, second capacitor C2, resonant capacitor C r , Excitation inductance L m , transformer T, first diode D1, second diode D2, third diode D3, fourth diode D4, third capacitor C O and output end; the seventh MOS tube S B1 The drain of the first MOS tube S1 and the input power supply V in The eighth MOS tube S B2 The source of the second MOS tube S2, the source of the fourth MOS tube S4 and the input power supply V in The eighth MOS tube S B2 The drain of the seventh MOS tube S B1 The source of the second MOS tube S2 is connected to the source of the first MOS tube S1, the drain of the fourth MOS tube S4 and the drain of the sixth MOS tube S6 are connected to the source of the third MOS tube S3, and the source of the fifth MOS tube S5 is connected to the source of the sixth MOS tube S6; the first inductor L B The first end of the seventh MOS tube S B1 The source of the second end is connected to the positive electrode of the first capacitor C1; the negative electrode of the second capacitor C2 is connected to the input power supply V in The positive electrode of the first capacitor C1, the drain of the third MOS tube S3 and the first inductor L B The second end of the first capacitor C1 is connected to the negative electrode, the drain of the fifth MOS tube S5 is connected to the positive electrode of the second capacitor C2; one end of the resonant inductor Lr is connected to the source of the third MOS tube S3, and the other end is connected to the same end of the primary side of the transformer T; the resonant capacitor C r One end of the excitation inductor L is connected to the source of the first MOS tube S1, and the other end is connected to the opposite end of the primary side of the transformer T; m The anode of the first diode D1 and the cathode of the second diode D2 are connected to the same-name end of the secondary side of the transformer T, and the anode of the third diode D3 and the cathode of the fourth diode D4 are connected to the opposite-name end of the secondary side of the transformer T; the cathode of the first diode D1, the cathode of the third diode D3, and the third capacitor C O The positive electrode of is connected to the positive electrode of the output terminal, the anode of the second diode D2, the anode of the fourth diode D4, the third capacitor C O The negative pole of is connected to the negative pole of the output terminal.

2. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: A diode and a capacitor are connected between the source and drain of the first MOS transistor S1, the second MOS transistor S2, the third MOS transistor S3, the fourth MOS transistor S4, the fifth MOS transistor S5 and the sixth MOS transistor S6, wherein the anode of each diode is respectively connected to the source of the first MOS transistor S1, the second MOS transistor S2, the third MOS transistor S3, the fourth MOS transistor S4, the fifth MOS transistor S5 and the sixth MOS transistor, and the cathode of each diode is respectively connected to the drain of the first MOS transistor S1, the second MOS transistor S2, the third MOS transistor S3, the fourth MOS transistor S4, the fifth MOS transistor S5 and the sixth MOS transistor.

3. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: The first MOS transistor S1 , the second MOS transistor S2 , the third MOS transistor S3 , the fourth MOS transistor S4 , the fifth MOS transistor S5 and the sixth MOS transistor S6 all adopt chips integrating a driving circuit and a protection circuit.

4. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: The first MOS transistor S1 , the second MOS transistor S2 , the third MOS transistor S3 , the fourth MOS transistor S4 , the fifth MOS transistor S5 and the sixth MOS transistor S6 all adopt gallium nitride power chips.

5. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: The transformer T is a double-winding transformer.

6. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: Also includes a fourth capacitor C B , the fourth capacitor C B The positive electrode and the first inductor L B The second end is connected to the negative terminal of the input power supply V in Negative pole connected.

7. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: The primary side of the transformer T is wound with Litz wire, and the secondary side is wound with copper foil.

8. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: The resonant inductor Lr is wound with Litz wire.

9. A series wide range LLC resonant converter topology structure according to claim 1, characterized in that: The first capacitor C1 and the second capacitor C2 have the same capacitance.

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