LLC resonant converter
By splitting the resonant inductor and magnetically integrating, two loops are formed to allocate the voltage of the parasitic capacitance, the problem of voltage spike of the secondary rectifier tube is solved, and efficient voltage suppression and power density are achieved.
Patent Information
- Application Number
- CN202421373909.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-17
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-06-17
AI Technical Summary
When the switching frequency is high, especially when the transformer uses a planar transformer, the primary resonant current oscillates at a high frequency, resulting in problems such as oscillation of the drain-source voltage of the secondary rectifier tube and large spikes.
By splitting the resonant inductor into two inductors that are magnetically integrated in one core, and using a coupling or decoupling integration method, two loops are formed to allocate the voltage of the parasitic capacitance, thereby suppressing the voltage spike of the secondary rectifier tube.
It is achieved to suppress voltage spikes in the secondary side rectifier tube, reduce the volume of the resonant inductor, and improve the power density.
Smart Images
Figure CN222674147U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electric energy conversion, and in particular to an LLC resonant converter. Background Art
[0002] Figure 1 is a circuit diagram of an existing LLC resonant converter. Figure 1 The LLC resonant converter includes a switch Q1, a switch Q2, a switch Q3, a switch Q4, a switch Q5, a switch Q6, a transformer T1, an inductor L r With capacitor C r , voltage V IN The positive electrode is connected to the first end of the switch Q1, the second end of the switch Q1 is connected to the first end of the switch Q2, and the second end of the switch Q2 is connected to the voltage V IN The negative electrode of the switch Q2, the second end of the switch Q2 is connected to the primary ground PGND, the first end of the switch Q3 is connected to the first end of the switch Q1, the second end of the switch Q3 is connected to the first end of the switch Q4, the second end of the switch Q4 is connected to the second end of the switch Q2, and the second end of the switch Q1 is connected to the primary ground PGND through the inductor L r The first end of the primary winding of the transformer T1 is connected to the second end of the primary winding of the transformer T1 through the capacitor C r The first end of the secondary winding of the transformer T1 is connected to the first end of the switch Q5, the second end of the switch Q5 is connected to the secondary ground SGND, the second end of the secondary winding of the transformer T1 is connected to the first end of the switch Q6, the second end of the switch Q6 is connected to the second end of the switch Q5, and the middle end of the secondary winding of the transformer T1 is connected to the capacitor C O The first end of the capacitor C O The second end of the capacitor C is connected to the second end of the switch Q6. O The output voltage V O Wherein, the inductor L r is the resonant inductor, the capacitor C r is a resonant capacitor, and the switch Q5 and the switch Q6 are secondary rectifier tubes.
[0003] When the switching frequency is high, especially when the transformer T1 adopts a planar transformer and the primary and secondary capacitances of the transformer T1 are large, the primary resonant current will oscillate at a high frequency, and the parasitic capacitance C of the switch Q5 will oss5 The parasitic capacitance C of switch Q6 oss6 The voltage difference between the two ends is large, which causes the drain-source voltage of the secondary rectifier tube to oscillate and have large spikes. Utility Model Content
[0004] The utility model aims to provide an LLC resonant converter, which can suppress the voltage spike of a secondary-side rectifier tube.
[0005] In order to achieve the above-mentioned purpose, the technical solution of the utility model is:
[0006] An LLC resonant converter comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a transformer, a first inductor, a second inductor and a first capacitor, wherein the second end of the first switch is connected to the first end of the second switch, the first end of the third switch is connected to the first end of the first switch, the second end of the third switch is connected to the first end of the fourth switch, the second end of the fourth switch is connected to the second end of the second switch, the second end of the first switch is connected to the first end of the first inductor, the second end of the first inductor is connected to the first end of the primary winding of the transformer, the second end of the primary winding of the transformer is connected to the first end of the second inductor via the first capacitor, the second end of the second inductor is connected to the first end of the fourth switch, the first end of the secondary winding of the transformer is connected to the first end of the fifth switch, the second end of the secondary winding of the transformer is connected to the first end of the sixth switch, and the second end of the sixth switch is connected to the second end of the fifth switch; the first inductor and the second inductor are magnetically integrated in a magnetic core.
[0007] In a specific embodiment, the first inductor and the second inductor are coupled and integrated.
[0008] In a specific embodiment, the first end of the first inductor and the first end of the second inductor are the same end.
[0009] In a specific embodiment, the first inductor and the second inductor are decoupled and integrated.
[0010] In a specific embodiment, the above LLC resonant converter further includes a second capacitor, a first end of the second capacitor is connected to the second end of the first inductor, and a second end of the second capacitor is connected to the first end of the primary winding of the transformer.
[0011] In a specific embodiment, the fifth switch and the sixth switch are MOSFETs.
[0012] In a specific embodiment, the fifth switch and the sixth switch are diodes.
[0013] More specifically, the positive electrode of the first voltage is connected to the first end of the first switch, and the second end of the second switch is connected to the negative electrode of the first voltage.
[0014] More specifically, the above-mentioned LLC resonant converter also includes an output capacitor, the middle end of the secondary winding of the transformer is connected to the first end of the output capacitor, the second end of the output capacitor is connected to the second end of the sixth switch, and the two ends of the output capacitor output a second voltage.
[0015] Beneficial effect: The utility model provides an LLC resonant converter, which can suppress the voltage spike of the secondary rectifier tube; the magnetic integration method can reduce the volume of the resonant inductor and improve the power density.
[0016] In order to make the above features and advantages of the utility model more obvious and easy to understand, embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 It is a circuit diagram of an existing LLC resonant converter.
[0018] Figure 2 This is a circuit diagram of a first specific embodiment of an LLC resonant converter of the utility model.
[0019] Figure 3 It is the equivalent circuit diagram of LLC resonant converter using coupled integration.
[0020] Figure 4 It is the equivalent circuit diagram of LLC resonant converter with decoupling integration.
[0021] Figure 5 This is a circuit diagram of a second specific embodiment of an LLC resonant converter of the utility model.
[0022] Figure 6 for Figure 5 An equivalent circuit diagram of a specific embodiment in FIG.
[0023] Figure 7 This is a circuit diagram of a third specific embodiment of an LLC resonant converter of the utility model.
[0024] Figure 8 This is a circuit diagram of a fourth specific embodiment of an LLC resonant converter of the utility model. DETAILED DESCRIPTION
[0025] In order to make the purpose and technical solution of the embodiment of the utility model clearer, the technical solution of the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings of the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the described embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0026] Figure 2 This is a circuit diagram of a first specific embodiment of an LLC resonant converter of the utility model. In this specific embodiment, the resonant inductor is split into two. Figure 2 The LLC resonant converter includes a switch Q1, a switch Q2, a switch Q3, a switch Q4, a switch Q5, a switch Q6, a transformer T1, an inductor L r1 、Inductance L r2 With capacitor C r , voltage V IN The positive electrode is connected to the first end of the switch Q1, the second end of the switch Q1 is connected to the first end of the switch Q2, and the second end of the switch Q2 is connected to the voltage V IN The negative electrode of the switch Q2, the second end of the switch Q2 is connected to the primary ground PGND, the first end of the switch Q3 is connected to the first end of the switch Q1, the second end of the switch Q3 is connected to the first end of the switch Q4, the second end of the switch Q4 is connected to the second end of the switch Q2, and the second end of the switch Q1 is connected to the inductor L r1 The first end of the inductor L r1 The second end of the primary winding of the transformer T1 is connected to the first end of the primary winding of the transformer T1, and the second end of the primary winding of the transformer T1 is connected to the first end of the primary winding of the transformer T1 through the capacitor C r Connect the inductor L r2 The first end of the inductor L r2 The second end of the secondary winding of the transformer T1 is connected to the first end of the switch Q5, the second end of the switch Q5 is connected to the secondary ground SGND, the second end of the secondary winding of the transformer T1 is connected to the first end of the switch Q6, the second end of the switch Q6 is connected to the second end of the switch Q5, and the middle end of the secondary winding of the transformer T1 is connected to the capacitor C O The first end of the capacitor C O The second end of the capacitor C is connected to the second end of the switch Q6. O The output voltage V O .
[0027] More specifically, the switch Q1 , the switch Q2 , the switch Q3 , the switch Q4 , the switch Q5 , and the switch Q6 are MOSFETs.
[0028] Among them, the inductance L r1 , the inductor L r2 is the resonant inductor, the capacitor C r is a resonant capacitor; the switch Q5 and the switch Q6 are secondary rectifiers, and the parasitic capacitance of the switch Q5 is C oss5 , the parasitic capacitance of the switch Q6 is Coss6 .
[0029] Furthermore, the inductor L r1 With the inductance L r2 The magnets are integrated into a core.
[0030] Optionally, the inductor L r1 With the inductance L r2 By adopting the coupling integration method, the inductor L r1 The first end of the inductor L r2 The first end of the same name.
[0031] Figure 3 The equivalent circuit diagram of the LLC resonant converter using coupled integration is shown. Among them, B is the midpoint of the bridge arm composed of switch Q1 and switch Q2, and A is the midpoint of the bridge arm composed of switch Q3 and switch Q4. When the LLC resonant converter is working normally, the voltage of point A to the primary ground PGND and the voltage of point B to the primary ground PGND can be regarded as square waves u A With square wave u B , square wave u A With square wave u B The frequency is the switching frequency of switch Q1, switch Q2, switch Q3 and switch Q4, square wave u A With square wave u B The amplitude is the voltage V IN Capacitor C ps is the primary and secondary equivalent capacitance of transformer T1, and the inductor L k1 With inductance L k2 is the secondary leakage inductance of transformer T1, capacitor C Y It is the equivalent capacitance between the primary ground PGND and the secondary ground SGND. r1 For inductance L r2 The mutual inductance is M 12 , inductance L r2 For inductance L r1 The mutual inductance is M 21 , M 12 =M 21 , the equivalent inductance between point A and transformer T1 is L r2 +M 21 , the equivalent inductance between point B and transformer T1 is L r1 +M 12 .
[0032] When switch Q6 is turned off, point B and inductor L r1 、M 12 , capacitor C ps 、Inductance L k2 , parasitic capacitance C oss6 , capacitor CY A loop is formed between point A and inductor L r2 、M 21 , capacitor C r , capacitor C ps 、Inductance L k2 , parasitic capacitance C oss6 , capacitor C Y A loop is formed between them, due to the inductance L r1 With inductance L r2 The impedance is large, the inductance L r1 With inductance L r2 The voltage at both ends is also large. When the total voltage of the circuit is constant, the parasitic capacitance C in the two circuits oss6 The voltages divided at both ends are small, so that the voltage spikes generated by point A and point B on the secondary rectifier are close, which can suppress the voltage spike of the secondary rectifier.
[0033] Similarly, when switch Q5 is turned off, point B and inductor L r1 、M 12 , capacitor C ps 、Inductance L k1 , parasitic capacitance C oss5 , capacitor C Y A loop is formed between point A and inductor L r2 、M 21 , capacitor C r , capacitor C ps 、Inductance L k1 , parasitic capacitance C oss5 , capacitor C Y A loop is formed between them, due to the inductance L r1 With inductance L r2 The impedance is large, the inductance L r1 With inductance L r2 The voltage at both ends is also large. When the total voltage of the circuit is constant, the parasitic capacitance C in the two circuits oss5 The voltages divided at both ends are small, so that the voltage spikes generated by point A and point B on the secondary rectifier are close, which can suppress the voltage spike of the secondary rectifier.
[0034] Optionally, the inductor L r1 With the inductance L r2 Using decoupled integration, the inductor L r1 With the inductance L r2 The coupling coefficient between them is 0.
[0035] Figure 4The equivalent circuit diagram of the LLC resonant converter using decoupled integration is shown. Among them, B is the midpoint of the bridge arm composed of switch Q1 and switch Q2, and A is the midpoint of the bridge arm composed of switch Q3 and switch Q4. When the LLC resonant converter is working normally, the voltage of point A to the primary ground PGND and the voltage of point B to the primary ground PGND can be regarded as square waves u A With square wave u B , square wave u A With square wave u B The frequency is the switching frequency of switch Q1, switch Q2, switch Q3 and switch Q4, square wave u A With square wave u B The amplitude is the voltage V IN Capacitor C ps is the primary and secondary equivalent capacitance of transformer T1, and the inductor L k1 With inductance L k2 is the secondary leakage inductance of transformer T1, capacitor C Y is the equivalent capacitance between the primary ground PGND and the secondary ground SGND, and the inductor L r1 With inductance L r2 There is no mutual induction between them.
[0036] When switch Q6 is turned off, point B and inductor L r1 , capacitor C ps 、Inductance L k2 , parasitic capacitance C oss6 , capacitor C Y A loop is formed between point A and inductor L r2 , capacitor C r , capacitor C ps 、Inductance L k2 , parasitic capacitance C oss6 , capacitor C Y A loop is formed between them, due to the inductance L r1 With inductance L r2 The impedance is large, the inductance L r1 With inductance L r2 The voltage at both ends is also large. When the total circuit voltage is constant, the parasitic capacitance C in the two circuits oss6 The voltages divided at both ends are small, so that the voltage spikes generated by point A and point B on the secondary rectifier are close, which can suppress the voltage spike of the secondary rectifier.
[0037] Similarly, when switch Q5 is turned off, point B and inductor L r1 , capacitor C ps 、Inductance L k1 , parasitic capacitance C oss5 , capacitor C Y A loop is formed between point A and inductor L r2 , capacitor Cr , capacitor C ps 、Inductance L k1 , parasitic capacitance C oss5 , capacitor C Y A loop is formed between them, due to the inductance L r1 With inductance L r2 The impedance is large, the inductance L r1 With inductance L r2 The voltage at both ends is also large. When the total circuit voltage is constant, the parasitic capacitance C in the two circuits oss5 The voltages divided at both ends are small, so that the voltage spikes generated by point A and point B on the secondary rectifier are close, which can suppress the voltage spike of the secondary rectifier.
[0038] Figure 5 This is a circuit diagram of a second specific embodiment of an LLC resonant converter of the utility model. In this specific embodiment, the resonant inductor and the resonant capacitor are both split into two. Figure 5 The LLC resonant converter includes a switch Q1, a switch Q2, a switch Q3, a switch Q4, a switch Q5, a switch Q6, a transformer T1, an inductor L r1 、Inductance L r2 , capacitor C r1 With capacitor C r2 , voltage V IN The positive electrode is connected to the first end of the switch Q1, the second end of the switch Q1 is connected to the first end of the switch Q2, and the second end of the switch Q2 is connected to the voltage V IN The negative electrode of the switch Q2, the second end of the switch Q2 is connected to the primary ground PGND, the first end of the switch Q3 is connected to the first end of the switch Q1, the second end of the switch Q3 is connected to the first end of the switch Q4, the second end of the switch Q4 is connected to the second end of the switch Q2, and the second end of the switch Q1 is connected to the inductor L r1 The first end of the inductor L r1 The second end passes through the capacitor C r1 The first end of the primary winding of the transformer T1 is connected to the second end of the primary winding of the transformer T1 through the capacitor C r2 Connect the inductor L r2 The first end of the inductor L r2 The second end of the secondary winding of the transformer T1 is connected to the first end of the switch Q5, the second end of the switch Q5 is connected to the secondary ground SGND, the second end of the secondary winding of the transformer T1 is connected to the first end of the switch Q6, the second end of the switch Q6 is connected to the second end of the switch Q5, and the middle end of the secondary winding of the transformer T1 is connected to the capacitor C O The first end of the capacitor C OThe second end of the capacitor C is connected to the second end of the switch Q6. O The output voltage V O .
[0039] More specifically, the switch Q1 , the switch Q2 , the switch Q3 , the switch Q4 , the switch Q5 , and the switch Q6 are MOSFETs.
[0040] Among them, the inductance L r1 , the inductor L r2 is the resonant inductor, the capacitor C r1 , the capacitor C r2 is a resonant capacitor; the switch Q5 and the switch Q6 are secondary rectifiers, and the parasitic capacitance of the switch Q5 is C oss5 , the parasitic capacitance of the switch Q6 is C oss6 .
[0041] Optionally, the inductor L r1 With the inductance L r2 Adopt coupled integration or decoupled integration, Figure 3 or Figure 4 The same as the embodiment in, which will not be repeated here.
[0042] Figure 6 Show Figure 5 The equivalent circuit diagram of the specific embodiment in Figure 6 In the r1 With the inductance L r2 The decoupling integration method is adopted. Among them, B is the midpoint of the bridge arm composed of switch Q1 and switch Q2, and A is the midpoint of the bridge arm composed of switch Q3 and switch Q4. When the LLC resonant converter is working normally, the voltage of point A to the primary ground PGND and the voltage of point B to the primary ground PGND can be regarded as square waves u A With square wave u B , square wave u A With square wave u B The frequency is the switching frequency of switch Q1, switch Q2, switch Q3 and switch Q4, square wave u A With square wave u B The amplitude is the voltage V IN Capacitor C ps is the primary and secondary equivalent capacitance of transformer T1, and the inductor L k1 With inductance L k2 is the secondary leakage inductance of transformer T1, capacitor C Y is the equivalent capacitance between the primary ground PGND and the secondary ground SGND, and the inductor L r1 With inductance L r2 There is no mutual induction between them.
[0043] When switch Q6 is turned off, point B and inductor L r1 , capacitor C r1 , capacitor C ps 、Inductance L k2 , parasitic capacitance C oss6 , capacitor C Y A loop is formed between point A and inductor L r2 , capacitor C r2 , capacitor C ps 、Inductance L k2 , parasitic capacitance C oss6 , capacitor C Y A loop is formed between them, and the impedance of the two loops is close, making the parasitic capacitance C oss6 The voltages divided in the two circuits are close, so that the voltage spikes generated by point A and point B on the secondary rectifier tube are close, which can suppress the voltage spike of the secondary rectifier tube.
[0044] Similarly, when switch Q5 is turned off, point B and inductor L r1 , capacitor C r1 , capacitor C ps 、Inductance L k1 , parasitic capacitance C oss5 , capacitor C Y A loop is formed between point A and inductor L r2 , capacitor C r2 , capacitor C ps 、Inductance L k1 , parasitic capacitance C oss5 , capacitor C Y A loop is formed between them, and the impedance of the two loops is close, making the parasitic capacitance C oss5 The voltages divided in the two circuits are close, so that the voltage spikes generated by point A and point B on the secondary rectifier tube are close, which can suppress the voltage spike of the secondary rectifier tube.
[0045] When a diode is used as the secondary rectifier tube of the LLC resonant converter, since the diode also has parasitic capacitance, the LLC resonant converter of the utility model can also suppress the voltage spike of the secondary diode.
[0046] Figure 7 This is a circuit diagram of a third specific embodiment of an LLC resonant converter of the utility model. In this specific embodiment, the resonant inductor is split into two. Figure 7 The LLC resonant converter includes a switch Q1, a switch Q2, a switch Q3, a switch Q4, a diode D5, a diode D6, a transformer T1, an inductor L r1 、Inductance L r2 With capacitor C r , voltage V INThe positive electrode is connected to the first end of the switch Q1, the second end of the switch Q1 is connected to the first end of the switch Q2, and the second end of the switch Q2 is connected to the voltage V IN The negative electrode of the switch Q2, the second end of the switch Q2 is connected to the primary ground PGND, the first end of the switch Q3 is connected to the first end of the switch Q1, the second end of the switch Q3 is connected to the first end of the switch Q4, the second end of the switch Q4 is connected to the second end of the switch Q2, and the second end of the switch Q1 is connected to the inductor L r1 The first end of the inductor L r1 The second end of the primary winding of the transformer T1 is connected to the first end of the primary winding of the transformer T1, and the second end of the primary winding of the transformer T1 is connected to the first end of the primary winding of the transformer T1 through the capacitor C r Connect the inductor L r2 The first end of the inductor L r2 The second end of the secondary winding of the transformer T1 is connected to the first end of the diode D5, the second end of the diode D5 is connected to the secondary ground SGND, the second end of the secondary winding of the transformer T1 is connected to the first end of the diode D6, the second end of the diode D6 is connected to the second end of the diode D5, and the middle end of the secondary winding of the transformer T1 is connected to the capacitor C O The first end of the capacitor C O The second end of the diode D6 is connected to the second end of the capacitor C O The output voltage V O .
[0047] More specifically, the switch Q1 , the switch Q2 , the switch Q3 , and the switch Q4 are MOSFETs.
[0048] Among them, the inductance L r1 , the inductor L r2 is the resonant inductor, the capacitor C r is the resonant capacitor; the diode D5 and the diode D6 are secondary rectifiers, and the parasitic capacitance of the diode D5 is C D5 , the parasitic capacitance of the diode D6 is C D6 .
[0049] Optionally, the inductor L r1 With the inductance L r2 Adopt coupled integration or decoupled integration approach.
[0050] The working principle of this specific embodiment is Figure 2 The working principle of the specific embodiment is similar and will not be repeated here.
[0051] Figure 8This is a circuit diagram of a fourth specific embodiment of an LLC resonant converter of the utility model. In this specific embodiment, the resonant inductor and the resonant capacitor are split into two. Figure 8 The LLC resonant converter includes a switch Q1, a switch Q2, a switch Q3, a switch Q4, a diode D5, a diode D6, a transformer T1, an inductor L r1 、Inductance L r2 , capacitor C r1 With capacitor C r2 , voltage V IN The positive electrode is connected to the first end of the switch Q1, the second end of the switch Q1 is connected to the first end of the switch Q2, and the second end of the switch Q2 is connected to the voltage V IN The negative electrode of the switch Q2, the second end of the switch Q2 is connected to the primary ground PGND, the first end of the switch Q3 is connected to the first end of the switch Q1, the second end of the switch Q3 is connected to the first end of the switch Q4, the second end of the switch Q4 is connected to the second end of the switch Q2, and the second end of the switch Q1 is connected to the inductor L r1 The first end of the inductor L r1 The second end passes through the capacitor C r1 The first end of the primary winding of the transformer T1 is connected to the second end of the primary winding of the transformer T1 through the capacitor C r2 Connect the inductor L r2 The first end of the inductor L r2 The second end of the secondary winding of the transformer T1 is connected to the first end of the diode D5, the second end of the diode D5 is connected to the secondary ground SGND, the second end of the secondary winding of the transformer T1 is connected to the first end of the diode D6, the second end of the diode D6 is connected to the second end of the diode D5, and the middle end of the secondary winding of the transformer T1 is connected to the capacitor C O The first end of the capacitor C O The second end of the diode D6 is connected to the second end of the capacitor C O The output voltage V O .
[0052] More specifically, the switch Q1 , the switch Q2 , the switch Q3 , and the switch Q4 are MOSFETs.
[0053] Among them, the inductance L r1 , the inductor L r2 is the resonant inductor, the capacitor C r1 , the capacitor C r2 is the resonant capacitor; the diode D5 and the diode D6 are secondary rectifiers, and the parasitic capacitance of the diode D5 is C D5, the parasitic capacitance of the diode D6 is C D6 .
[0054] Optionally, the inductor L r1 With the inductance L r2 Adopt coupled integration or decoupled integration approach.
[0055] The working principle of this specific embodiment is Figure 5 The working principle of the specific embodiment is similar and will not be repeated here.
[0056] Although the present invention has been disclosed as above by the embodiments, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.
Claims
1. An LLC resonant converter, characterized in that: The invention comprises a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a transformer, a first inductor, a second inductor and a first capacitor, wherein the second end of the first switch is connected to the first end of the second switch, the first end of the third switch is connected to the first end of the first switch, the second end of the third switch is connected to the first end of the fourth switch, the second end of the fourth switch is connected to the second end of the second switch, the second end of the first switch is connected to the first end of the first inductor, the second end of the first inductor is connected to the first end of the primary winding of the transformer, the second end of the primary winding of the transformer is connected to the first end of the second inductor via the first capacitor, the second end of the second inductor is connected to the first end of the fourth switch, the first end of the secondary winding of the transformer is connected to the first end of the fifth switch, the second end of the secondary winding of the transformer is connected to the first end of the sixth switch, and the second end of the sixth switch is connected to the second end of the fifth switch; the first inductor and the second inductor are magnetically integrated in a magnetic core.
2. An LLC resonant converter as claimed in claim 1, characterized in that: The first inductor and the second inductor are coupled and integrated.
3. An LLC resonant converter as claimed in claim 2, characterized in that: The first end of the first inductor and the first end of the second inductor are the same end.
4. An LLC resonant converter as claimed in claim 1, characterized in that: The first inductor and the second inductor are decoupled and integrated.
5. An LLC resonant converter according to any one of claims 1 to 4, characterized in that: It also includes a second capacitor, a first end of the second capacitor is connected to the second end of the first inductor, and a second end of the second capacitor is connected to the first end of the primary winding of the transformer.
6. An LLC resonant converter as claimed in claim 1, characterized in that: The fifth switch and the sixth switch are MOSFETs.
7. An LLC resonant converter as claimed in claim 1, characterized in that: The fifth switch and the sixth switch are diodes.
8. An LLC resonant converter as claimed in claim 1, characterized in that: The positive electrode of the first voltage is connected to the first end of the first switch, and the second end of the second switch is connected to the negative electrode of the first voltage.
9. An LLC resonant converter as claimed in claim 1, characterized in that: It also includes an output capacitor, the middle end of the secondary winding of the transformer is connected to the first end of the output capacitor, the second end of the output capacitor is connected to the second end of the sixth switch, and the two ends of the output capacitor output a second voltage.