DC-DC converter of magnetic integrated foil position hybrid circuit

Abstract

The utility model belongs to the technical field of DC-DC converters, and discloses a DC-DC converter of a magnetic integrated foil position hybrid circuit, the converter integrates a phase-shifted full-bridge converter and a half-bridge LLC converter, a lagging bridge arm of the phase-shifted full-bridge converter at the primary side of the converter is shared with the half-bridge LLC converter, and the lagging bridge arm is shared with the half-bridge LLC converter. And the secondary side is formed by connecting the full-bridge rectifier with the rectifier of the half-bridge LLC converter in series, so that the converter can output higher voltage. The converter further comprises a novel clamping circuit which is composed of two diodes and a capacitor connected to the center of the transformer. The DC-DC converter provided by the utility model has the advantages of no circulating current loss, small reverse recovery current, small output inductance and the like, and the conversion efficiency and the power density of the converter are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of DC-DC converters, and in particular relates to a DC-DC converter of a magnetic integrated foil bit hybrid circuit. Background Art

[0002] On-board chargers (OBCs) consist of two power stages: a PFC stage and a DC-DC stage. The phase-shifted full-bridge (PSFB) converter is the most widely used DC / DC converter for OBCs. However, several limitations must be addressed. First, achieving hysteretic switching (ZVS) with the PSFB converter is difficult. Second, the large circulating current on the primary side during freewheeling increases conduction losses on the primary side. Third, the voltage stress on the secondary-side full-bridge rectifier is relatively high. Fourth, the reverse recovery current on the full-bridge rectifier is very high. In summary, the PSFB converter has certain limitations that need to be addressed to improve efficiency, power density, and cost.

[0003] The Chinese patent publication number is CN111313708A, titled "A Full-Bridge DC-DC Converter." Two split capacitors are added to the primary side, connected in series to the high-voltage DC input. The two split capacitors have different voltages, determined by the duty cycle of the switching transistor. The primary side contains two transformers, with the two primary windings connected to the midpoints of the switching transistor bridge arm and the midpoint of the series capacitor bridge arm, respectively. The secondary side comprises a rectifier bridge consisting of the transformer secondary windings and diodes. The outputs of all diodes share a filter inductor and an output filter capacitor. This patent application can reduce circulating current, switching loss, and conduction loss, but it does not address the high voltage stress of the secondary-side full-bridge rectifier. Utility Model Content

[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 DC-DC converter with a magnetic integrated foil hybrid circuit. The lag branch of the phase-shifted full-bridge converter is shared with the half-bridge LLC converter. The half-bridge LLC converter replaces the traditional resonant inductor with a leakage inductor, overcomes many shortcomings of the traditional phase-shifted full-bridge converter, and improves the conversion efficiency and power density of the converter.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A DC-DC converter of a magnetic integrated foil bit hybrid circuit, comprising: a power supply V in , first switch tube S1, second switch tube S2, third switch tube S3, fourth switch tube S4, first transformer T1, second transformer T2, first leakage inductor L leak1 , the second leakage inductance L leak2 , resonant capacitor Cr , a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, a ninth diode D9, a ninth capacitor C9, a twelfth diode D12, a first power tube Q1, a second power tube Q2, a first output capacitor C12 and a second output capacitor C13; the power supply V in The positive electrode is connected to the drain of the first switch tube S1 and the drain of the second switch tube S2, and the power supply V in The negative electrode of the transistor is connected to the source of the third switch tube S3 and the source of the fourth switch tube S4 respectively; the source of the first switch tube S1 and the drain of the third switch tube S3 are connected to form a first bridge arm, and the source of the second switch tube S2 and the drain of the fourth switch tube S4 are connected to form a lagging bridge arm; the first transformer T1 is connected to the midpoint of the first bridge arm; the second leakage inductor L leak2 Integrated in the second transformer T2, the second leakage inductance L leak2 One end of the hysteresis bridge arm is connected to the midpoint of the bridge arm, and the other end is connected to the second transformer T2. The other end of the second transformer T2 is connected to the resonant capacitor C r The source of the third switch tube S3 and the source of the fourth switch tube S4 are connected to the resonant capacitor C r The anode of the fifth diode D5 is connected to the cathode of the seventh diode D7 to form a second bridge arm, and the anode of the sixth diode D6 is connected to the cathode of the eighth diode D8 to form a third bridge arm; the secondary side of the first transformer T1 is connected to the midpoint of the second bridge arm and the third bridge arm; the fifth diode D5 is connected to the cathode of the sixth diode D6; the cathode of the seventh diode D7 is connected to the cathode of the eighth diode D8; the anode of the twelfth diode D12 is connected to the midpoint of the secondary side of the first transformer T1; the anode of the ninth diode D9 is connected to the positive electrode of the ninth capacitor C9, the negative electrode of the ninth capacitor C9 is connected to the anode of the eighth diode D8, the cathode of the ninth diode D9 is connected to the cathode of the sixth diode D6, and the cathode of the twelfth diode D12 is connected to the anode of the ninth diode D9; The anode of the diode D12 is connected to the midpoint of the secondary side of the first transformer T1; the anode of the ninth diode D9 is connected to the positive electrode of the ninth capacitor C9, the negative electrode of the ninth capacitor C9 is connected to the anode of the eighth diode D8, the cathode of the ninth diode D9 is connected to the cathode of the sixth diode D6, and the cathode of the twelfth diode D12 is connected to the anode of the ninth diode D9; the first output capacitor C12 is connected to the cathode of the ninth diode D9, and the other end of the first output capacitor C12 is connected to the anode of the eighth diode D8; the collector of the first power transistor Q1 is connected to the collector of the second power transistor Q2, the negative electrode of the second output capacitor C13 is also connected to the collectors of the first power transistor Q1 and the second power transistor Q2, and the positive electrode of the second output capacitor C13 is connected to the center point of the secondary side of the second transformer T2.

[0007] Optionally, a load R0 is further included, and two ends of the load R0 are connected to the first output capacitor C12 and the second output capacitor C13 respectively.

[0008] Optionally, the first switch tube S1 , the second switch tube S2 , the third switch tube S3 , and the fourth switch tube S4 are all MOSFET switch tubes.

[0009] Optionally, the first switch tube S1 , the second switch tube S2 , the third switch tube S3 , and the fourth switch tube S4 all have parasitic diodes and parasitic capacitors.

[0010] Optionally, the first transformer T1 and the second transformer T2 are both planar transformers; the first leakage inductance L leak1 The magnetic is integrated in the first transformer T1, the second leakage inductor L leak2 The magnetics are integrated into the second transformer T2.

[0011] Optionally, the secondary side of the second transformer T2 has a center tap, and the emitter of the first switch tube Q1 is connected to the secondary side N of the second transformer T2. s1 The same-named ends are connected.

[0012] Optionally, the fifth diode D5, the sixth diode D6, the seventh diode D7 and the eighth diode D8 are all rectifier diodes, and the model is IDH15S120; the model of the twelfth diode D12 is 20CTH03.

[0013] Optionally, the fifth diode D5 , the sixth diode D6 , the seventh diode D7 and the eighth diode D8 all have parasitic capacitance.

[0014] Optionally, a filter inductor L2 is further included, one end of the filter inductor L2 is connected to the cathode of the ninth diode D9, and the other end of the filter inductor L2 is connected to the first output capacitor C12.

[0015] Optionally, both the first power tube Q1 and the second power tube Q2 are IGBT power tubes.

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

[0017] The utility model discloses an improved DC-DC converter with a magnetically integrated foil-bit hybrid circuit. The lag branch of the phase-shifted full-bridge converter is shared with the half-bridge LLC converter, and the half-bridge LLC converter uses leakage inductance instead of the traditional resonant inductor. The secondary side of the DC-DC converter is a full-bridge rectifier and a rectifier of a half-bridge LLC converter connected in series, so that the converter can output a higher voltage. The clamping circuit of the DC-DC converter of the utility model consists of two diodes and a capacitor, and is connected to the midpoint of the secondary side transformer. The utility model has the advantages of no circulating current loss, small voltage stress of the rectifier diode on the secondary side of the converter, small reverse recovery current, small output inductance and small output current, thereby improving the conversion efficiency and power density of the converter.

[0018] Furthermore, the transformer of the present invention uses a planar transformer, which has the advantage of high power density, and the leakage inductance is integrated into the transformer in a magnetic integration manner, thereby reducing the volume of the DC-DC converter of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are merely schematic and are used to help understand the present invention, and are not intended to specifically limit the shapes and proportional dimensions of the components of the present invention. In the drawings:

[0020] Figure 1 This is a schematic diagram of the circuit of the utility model;

[0021] Figure 2 This is a current flow diagram of a mode 1 converter in Example 2 of the present utility model;

[0022] Figure 3 This is the current flow diagram of the mode 2 converter of embodiment 2 of the utility model

[0023] Figure 4 This is the current flow diagram of the modal three converter of Example 2 of the present utility model;

[0024] Figure 5 This is the current flow diagram of the modal four-converter of Example 2 of the present utility model;

[0025] Figure 6 This is the current flow diagram of the mode five converter in Example 2 of the present utility model;

[0026] Figure 7 This is the current flow diagram of the modal six converter of Example 2 of the present utility model;

[0027] Figure 8 This is a working timing diagram of Example 2 of the present utility model. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0029] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an element centered thereon. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an element centered thereon. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of this invention are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] The present invention will be described in detail below with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the utility model is a DC-DC converter of a magnetic integrated foil hybrid circuit, including: a power supply V in , first switch tube S1, second switch tube S2, third switch tube S3, fourth switch tube S4, first transformer T1, second transformer T2, first leakage inductor L leak1 , the second leakage inductance L leak2 , resonant capacitor C r , fifth diode D5, sixth diode D6, seventh diode D7, eighth diode D8, ninth capacitor C9, twelfth diode D12, first power tube Q1, second power tube Q2, filter inductor L2, first output capacitor C12 and second output capacitor C13.

[0033] Among them, the power supply V in , the first switch tube S1, the second switch tube S2, the third switch tube S3, the fourth switch tube S4, the first transformer T1, the second transformer T2, the first leakage inductor L leak1 , the second leakage inductance L leak2 , resonant capacitor Cr Belongs to the primary side of the converter.

[0034] The fifth diode D5, the sixth diode D6, the seventh diode D7, the eighth diode D8, the ninth capacitor C9, the ninth diode D9, the twelfth diode D12, the first power tube Q1, and the second power tube Q2 belong to the secondary side of the converter.

[0035] The fifth diode D5, the sixth diode D6, the seventh diode D7, and the eighth diode D8 belong to the full-bridge rectifier part of the phase-shifted full-bridge converter.

[0036] The first switch tube S1, the second switch tube S2, the second transformer T2, the second leakage inductor L leak2 , resonant capacitor C r Belonging to the primary side of the half-bridge LLC converter, the first power tube Q1, the second power tube Q2 and the second output capacitor C13 belong to the half-bridge LLC converter.

[0037] The power supply V in The positive electrode is connected to the drain of the first switch tube S1 and the drain of the second switch tube S2, and the power supply V in The negative electrode of the transistor is connected to the source of the third switch tube S3 and the source of the fourth switch tube S4 respectively; the source of the first switch tube S1 and the drain of the third switch tube S3 are connected to form a first bridge arm, and the source of the second switch tube S2 and the drain of the fourth switch tube S4 are connected to form a lagging bridge arm; the first transformer T1 is connected to the midpoint of the first bridge arm; the second leakage inductor L leak2 Integrated in the second transformer T2, the first leakage inductance L leak1 One end of the hysteresis bridge arm is connected to the midpoint of the bridge arm, and the other end is connected to the second transformer T2. The other end of the second transformer T2 is connected to the resonant capacitor C r The source of the third switch tube S3 and the source of the fourth switch tube S4 are connected to the resonant capacitor C rThe anode of the fifth diode D5 is connected to the cathode of the seventh diode D7 to form a second bridge arm, and the anode of the sixth diode D6 and the cathode of the eighth diode D8 are connected to form a third bridge arm; the secondary side of the first transformer T1 is connected to the midpoint of the second bridge arm and the third bridge arm; the fifth diode D5 and the cathode of the sixth diode D6 are connected; the cathode of the seventh diode D7 and the cathode of the eighth diode D8 are connected; the anode of the twelfth diode D12 is connected to the midpoint of the secondary side of the first transformer T1; the anode of the ninth diode D9 is connected to the positive electrode of the ninth capacitor C9, the negative electrode of the ninth capacitor C9 is connected to the anode of the eighth diode D8, the cathode of the ninth diode D9 is connected to the cathode of the sixth diode D6, and the cathode of the twelfth diode D12 is connected to the anode of the ninth diode D9; the anode of the twelfth diode D12 is connected to the midpoint of the secondary side of the first transformer T1. The anode of the ninth diode D9 is connected to the positive electrode of the ninth capacitor C9, the negative electrode of the ninth capacitor C9 is connected to the anode of the eighth diode D8, the cathode of the ninth diode D9 is connected to the cathode of the sixth diode D6, and the cathode of the twelfth diode D12 is connected to the anode of the ninth diode D9; the filter inductor L2 is connected to the cathode of the ninth diode D9, the first output capacitor C12 is connected to the filter inductor L2, and the other end of the first output capacitor C12 is connected to the anode of the eighth diode D8; the collector of the first power tube Q1 is connected to the collector of the second power tube Q2, the negative electrode of the second output capacitor C13 is also connected to the collectors of the first power tube Q1 and the second power tube Q2, and the positive electrode of the second output capacitor C13 is connected to the center point of the secondary side of the second transformer T2.

[0038] The lag branch of the phase-shifted full-bridge converter of this utility model is shared with the half-bridge LLC converter, which replaces the traditional resonant inductor with a leakage inductor. The secondary side of the DC-DC converter consists of a full-bridge rectifier and the rectifier of the half-bridge LLC converter connected in series, enabling the converter to output a higher voltage. The clamping circuit consists of two diodes and a capacitor and is connected to the midpoint of the secondary transformer. This utility model overcomes many shortcomings of traditional phase-shifted full-bridge converters and improves the converter's conversion efficiency and power density.

[0039] Example 1

[0040] Figure 1 In the power supply V in It is the power supply of the DC / DC converter, and the input terminal voltage is a DC voltage.

[0041] Power supply V in The positive electrode is connected to the drain of the first switch tube S1 and the drain of the second switch tube S2, and the power supply V inThe negative electrodes of the first and second switching transistors S1 and S2 are connected to the sources of the third and fourth switching transistors S3 and S4, respectively. The source of the first switching transistor S1 and the drain of the third switching transistor S3 are connected to form a first bridge arm, and the source of the second switching transistor S2 and the drain of the fourth switching transistor S4 are connected to form a lagging bridge arm. The two bridge arms form the inverter portion of the phase-shifted full-bridge converter.

[0042] The first transformer T1 and the first leakage inductor L leak1 Connected to the midpoint of the first bridge arm and the lagging bridge arm. In fact, the second leakage inductance L leak2 It is integrated into the second transformer T2 and when working, L leak2 The function of the traditional resonant inductor is replaced, which reduces the number of circuit components and reduces the cost. The hysteresis bridge arm formed by the connection of the source of the second switch tube S2 and the drain of the fourth switch tube S4 is also the bridge arm of the half-bridge LLC circuit.

[0043] The first leakage inductance L leak1 One end of the hysteresis bridge arm is connected to the midpoint of the bridge arm, and the other end is connected to the second transformer T2. The other end of the second transformer T2 is connected to the resonant capacitor C r The negative electrode of the third switch tube S3 and the source of the fourth switch tube S4 are connected to the resonant capacitor C r The positive electrode is connected.

[0044] Specifically, the first switch tube S1 , the second switch tube S2 , the third switch tube S3 , and the fourth switch tube S4 are all MOSFET switch tubes, model IPP90R340C3.

[0045] The first switching transistor S1, the second switching transistor S2, the third switching transistor S3, and the fourth switching transistor S4 all have parasitic diodes and parasitic capacitors. The parasitic diodes are respectively a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4; and the parasitic capacitors are respectively a first capacitor C1, a second capacitor C2, a third capacitor C3, and a fourth capacitor C4.

[0046] The first transformer T1 and the second transformer T2 are both planar transformers, and the core material of both is PQ3535. The first transformer T1 is a planar transformer of the phase-shifted full-bridge converter. The leakage inductance and stray inductance of the first transformer T1 integrate the first leakage inductance L leak1 , the first leakage inductance L leak1 Integrated in the planar first transformer T1.

[0047] The second transformer T2 is a planar transformer of the half-bridge LLC converter. The second transformer T2 has an excitation inductance L m2 and resonant capacitor C r , the leakage inductance and stray inductance of the second transformer T2 integrate the second leakage inductance L leak2 , the L leak2Integrated in the second planar transformer T2, when the converter is working, L leak2 Replace the traditional resonant inductor and resonant capacitor C r Resonance occurs.

[0048] The connection mode of the secondary side of the converter of the utility model is:

[0049] The anode of the fifth diode D5 and the cathode of the seventh diode D7 are connected to form a second bridge arm, and the anode of the sixth diode D6 and the cathode of the eighth diode D8 are connected to form a third bridge arm; the secondary side of the first transformer T1 is connected to the midpoint of the second bridge arm and the third bridge arm.

[0050] The cathodes of the fifth diode D5 and the sixth diode D6 are connected. The cathodes of the seventh diode D7 and the eighth diode D8 are connected.

[0051] In the clamping circuit, the anode of the twelfth diode D12 is connected to the midpoint of the secondary side of the first transformer T1. The anode of the ninth diode D9 is connected to the positive electrode of the ninth capacitor C9, the negative electrode of the ninth capacitor C9 is connected to the anode of the eighth diode D8, the cathode of the ninth diode D9 is connected to the cathode of the sixth diode D6, and the cathode of the twelfth diode D12 is connected to the anode of the ninth diode D9.

[0052] The filter inductor L2 is connected to the cathode of the ninth diode D9 , the first output capacitor C12 of the phase-shifted full-bridge converter is connected to the filter inductor L2 , and the other end of the first output capacitor C12 is connected to the anode of the eighth diode D8 .

[0053] The secondary side of the second transformer T2 has a center tap, and the emitter of the first switch tube Q1 is connected to the secondary side N of the second transformer T2. s1 The same-named ends are connected.

[0054] The collector of the first switching tube Q1 is connected to the collector of the second switching tube Q2, the negative electrode of the second output capacitor C13 is also connected to the collectors of the first switching tube Q and the second switching tube Q2, and the positive electrode of the second output capacitor C13 is connected to the center point of the secondary side of the second transformer T2.

[0055] The emitter of the second switch tube Q2 is connected to the secondary side N of the second transformer T2. s2 The output of the half-bridge LLC converter is connected in series with the output of the phase-shifted full-bridge converter, making the converter suitable for fast chargers in DC / DC converters that require high output voltage.

[0056] Specifically, the fifth diode D5, the sixth diode D6, the seventh diode D7 and the eighth diode D8 are all rectifier diodes of the phase-shifted full-bridge circuit, and the model is IDH15S120.

[0057] The fifth capacitor C5 , the sixth capacitor C6 , the seventh capacitor C7 and the eighth capacitor C8 are parasitic capacitances of the fifth diode D5 , the sixth diode D6 , the seventh diode D7 and the eighth diode D8 , respectively.

[0058] The ninth diode D9, the twelfth diode D12 and the ninth capacitor C9 form a clamping circuit. The twelfth diode D12 is 20CTH03, the ninth diode D9 is 10ETF02 (600V), and the tenth capacitor C10 is the output capacitor of the phase-shifted full-bridge converter.

[0059] The secondary side of the first transformer T1 is nT1, where n is the turns ratio of the transformer. The secondary side of the second transformer T2 is N s1 、N s2 The first power tube Q1 and the second power tube Q2 are two switch tubes on the secondary side of the LLC circuit. The first power tube Q1 and the second power tube Q2 are both IGBT power tubes, model DXG25N120CN. The thirteenth capacitor C13 is the output capacitor of the LLC circuit.

[0060] Example 2

[0061] The converter of the present invention has a total of 12 modes in one cycle, 6 modes in the upper half cycle and 6 modes in the lower half cycle. Since the modes of the upper and lower half cycles are symmetrical to each other, only the 6 working modes of the upper half cycle are introduced here.

[0062] Mode 1: When the commutation from the clamped twelfth diode D12 to the fifth diodes D5 and D8 of the full-bridge rectifier is completed, the mode starts. In this mode, the first switch tube S1 and the fourth switch tube S4 are in the on state, and the current flows from the power supply V in The positive electrode passes through the first switch tube S1 and the leakage inductance L of the first transformer T1. leak1 , the first transformer T1, the fourth switch tube S4, and finally back to the power supply V in The negative pole of the second transformer T2. leak2 and the resonant capacitor C r Resonance occurs, and the resonant current passes through the leakage inductance L leak2 , the fourth switch tube S4, the resonant capacitor C r A loop is formed, and the loop flow direction is as follows Figure 2 When the twelfth clamping diode D12 is turned on, it provides a clamping path so that the voltage at the center point of the secondary side of T1 is V c9 , which causes the output voltage of the phase-shifted full-bridge converter to be clamped at 2V c9 , effectively reducing the voltage stress, and this clamping circuit can use diodes with lower rated voltage, thereby reducing the conduction loss of the full-bridge rectifier.

[0063] The secondary rectifier current flows as follows Figure 2 As shown, the current flows through the fifth diode D5, the filter inductor L2, the first output capacitor C12, the eighth diode D8, and then returns to the anode of the fifth diode D5 through the transformer. The current in the clamping circuit flows from the center point of the secondary side of the first transformer T1 to the anode of the twelfth clamping diode D12, then through the ninth capacitor C9 and the eighth diode D8 to complete the loop. The current on the secondary side of the half-bridge LLC converter flows to capacitor C13, completing the loop through the second switch Q2. The outputs of the full-bridge rectifier and the half-bridge LLC resonant converter are connected in series, and the two converters together supply energy to the load R0.

[0064] Mode 2: When the first switch S1 is turned off, mode 2 begins. The junction capacitance of the first switch S1 and S3 is connected through the first leakage inductance L leak1 The first capacitor C1 of the first switch tube S1 is charged and discharged. The charging circuit is as follows Figure 3 As shown, from the power supply V in The positive electrode passes through the junction capacitance of the first switch tube S1 and the leakage inductance L of the first transformer T1. leak1 , the first transformer T1, the fourth switch tube S4 and finally return to the power supply V in of the negative electrode.

[0065] The junction capacitance discharge loop of the third switch tube S3 is: the positive electrode of the third capacitor C3 of the third switch tube S3, the first leakage inductance L of the first transformer T1 leak1 The first transformer T1, the fourth switch S4, and finally the negative electrode of the junction capacitor S3 are discharged. After the parasitic capacitance of S3 is discharged, preparations are made for the next phase of zero-voltage switching. In this mode, the current in the full-bridge rectifier on the secondary side of the converter flows through the fifth diode D5, the filter inductor L2, the first output capacitor C12, the eighth diode D8, and then returns to the anode of the fifth diode D5 through the transformer. The secondary current flow of the LLC converter is the same as in mode 1. Similarly, the output of the phase-shifted full-bridge converter and the output of the half-bridge LLC converter combine to provide energy to the load.

[0066] Mode 3: In this mode, the commutation is transferred from the fifth diode D5 and D8 of the full-bridge rectifier to the ninth clamp diode D9. Since switches S3, S4 and diodes D5, D8 and D9 are turned on, the voltage V c9 Reflected to the primary side of the first transformer T1, making V Lleak1 =-V C9 / nT1, due to V Lleak1 is negative, so the current i p1 Gradually decreases, i p1 The current loop is as follows Figure 4As shown, a loop is formed through the first transformer T1, the fourth switch tube S4, and the third switch tube S3. The primary current flows through the first transformer T1, the fourth switch tube S4, the third switch tube S3, and finally back to the first transformer T1. At the primary end of the converter, the current flow of the half-bridge LLC converter is the same as the aforementioned mode. The current flow of the full-bridge rectifier on the secondary side of the converter is through the fifth diode D5, the filter inductor L2, the first output capacitor C12, the eighth diode D8, and then returns to the anode of the fifth diode D5 through the transformer. The current flow of the clamping circuit is through the positive electrode of the ninth capacitor C9, the filter inductor L2, the first output capacitor C12, and finally back to the negative electrode of the ninth capacitor C9.

[0067] The current flow on the LLC converter's secondary side is the same as in Mode 1. The secondary-side full-bridge rectifier and the half-bridge LLC converter output are connected in series, and together they supply energy to the load. There is no circulating current in this stage because power continues to be delivered to the secondary side at a positive voltage through the first transformer T1. This means that the clamping circuit eliminates circulating current on the primary side, reducing conduction losses.

[0068] Mode 4: When the fifth diode D5 and the eighth diode D8 are turned off, this mode begins. In this mode, the reverse voltage of the fifth diode D5 and the eighth diode D8 rises to V c9 This voltage is smaller than the voltage observed in a conventional phase-shifted full-bridge converter. Therefore, due to the small reverse voltage, the losses of the fifth diode D5 and the eighth diode D8 are significantly reduced.

[0069] According to the equivalent circuit of mode 4, the output voltage of the full-bridge rectifier is limited to V c9 , which results in a much lower voltage on the filter inductor L2, thereby reducing the size of L2. The four diodes of the full-bridge rectifier are all turned off, and since the magnetizing inductance of the first transformer T1 is large, the first leakage inductor L leak1 Current i p1 is zero, so only the half-bridge LLC converter at the primary end of the converter transfers energy to the secondary side. The current flow direction of the LLC circuit in this mode is the same as that in the aforementioned mode 1. This stage ends when the excitation current and the resonant current are equal.

[0070] Mode 5: When the hysteresis switch S4 is closed, this mode starts. In this stage, the primary side of the converter does not transfer energy to the secondary side, that is, the current i p1 The current flow on the primary side of the half-bridge LLC converter is as follows: Figure 6 As shown, at this time the excitation inductance L m2 The current gradually decreases (LLC converter secondary current decreases to 0), when the Np current is greater than L m2 When the current flows, the current will discharge the capacitor C2 and charge the capacitor C4, and the charge and discharge circuit of the capacitor C4 is as follows: Figure 6After capacitors C2 and C4 have completed charging and discharging, the current will form a loop through the parasitic diode of the second switch S2, waiting for the second switch S2 to turn on. On the secondary side of the converter, the first output capacitor C12 of the phase-shifted full-bridge converter and the second output capacitor C13 of the LLC converter are connected in series to power the load.

[0071] Mode 6: When the drain-source voltage of S4 V Ds4 When it reaches 0, the mode starts. In this mode, the current is commutated from D9 to the sixth diode D6 and D7 of the full bridge rectifier. When S2, S3, D9, D6, and D7 are turned on, the voltage V c9 Reflected to the original side, so that i p1 The current decreases. In this mode, the current on the primary side of the converter flows as follows Figure 7 As shown, the power supply V in The positive electrode flows back to the power supply V through the first transformer T1 and the third switch tube S3. in The negative pole of the half-bridge LLC converter; the leakage inductance L leak2 and the resonant capacitor C r Resonance occurs, the excitation inductance L m2 Energy storage, LLC converter secondary current gradually increases. The converter secondary current flow direction is as follows Figure 7 As shown, the current returns to the other end of the secondary side of the first transformer T1 through the anode of the sixth diode D6, the filter inductor L2, the first output capacitor C12, and the seventh diode D7. The first output capacitors C12 and C13 together supply energy to the load.

[0072] Unless otherwise specified, the device components involved in the above embodiments are all conventional device components, and the structural settings, working modes or control modes involved are all conventional settings, working modes or control modes in the art unless otherwise specified.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not limiting. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.

Claims

1. A DC-DC converter of a magnetic integrated foil hybrid circuit, characterized in that: include: Power supply V in , first switch tube S1, second switch tube S2, third switch tube S3, fourth switch tube S4, first transformer T1, second transformer T2, first leakage inductor L leak1 , the second leakage inductance L leak2 , resonant capacitor C r , a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, a ninth diode D9, a ninth capacitor C9, a twelfth diode D12, a first power tube Q1, a second power tube Q2, a first output capacitor C12 and a second output capacitor C13; the power supply V in The positive electrode is connected to the drain of the first switch tube S1 and the drain of the second switch tube S2, and the power supply V in The negative electrode of the transistor is connected to the source of the third switch tube S3 and the source of the fourth switch tube S4 respectively; the source of the first switch tube S1 and the drain of the third switch tube S3 are connected to form a first bridge arm, and the source of the second switch tube S2 and the drain of the fourth switch tube S4 are connected to form a lagging bridge arm; the first transformer T1 is connected to the midpoint of the first bridge arm; the second leakage inductor L leak2 Integrated in the second transformer T2, the second leakage inductance L leak2 One end of the hysteresis bridge arm is connected to the midpoint of the bridge arm, and the other end is connected to the second transformer T2. The other end of the second transformer T2 is connected to the resonant capacitor C r The source of the third switch tube S3 and the source of the fourth switch tube S4 are connected to the resonant capacitor C r The anode of the fifth diode D5 is connected to the cathode of the seventh diode D7 to form a second bridge arm, and the anode of the sixth diode D6 is connected to the cathode of the eighth diode D8 to form a third bridge arm; the secondary side of the first transformer T1 is connected to the midpoint of the second bridge arm and the third bridge arm; the fifth diode D5 is connected to the cathode of the sixth diode D6; the cathode of the seventh diode D7 is connected to the cathode of the eighth diode D8; the anode of the twelfth diode D12 is connected to the midpoint of the secondary side of the first transformer T1; the anode of the ninth diode D9 is connected to the positive electrode of the ninth capacitor C9, and the negative electrode of the ninth capacitor C9 is connected to the negative electrode of the eighth diode The anode of the ninth diode D8 is connected to the cathode of the ninth diode D9, the cathode of the sixth diode D6 is connected to the cathode of the twelfth diode D12 is connected to the anode of the ninth diode D9; the first output capacitor C12 is connected to the cathode of the ninth diode D9, and the other end of the first output capacitor C12 is connected to the anode of the eighth diode D8; the collector of the first power tube Q1 is connected to the collector of the second power tube Q2, the cathode of the second output capacitor C13 is also connected to the collectors of the first power tube Q1 and the second power tube Q2, and the positive electrode of the second output capacitor C13 is connected to the center point of the secondary side of the second transformer T2.

2. The DC-DC converter of a magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The device further includes a load R0 , wherein both ends of the load R0 are connected to the first output capacitor C12 and the second output capacitor C13 , respectively.

3. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The first switch tube S1 , the second switch tube S2 , the third switch tube S3 , and the fourth switch tube S4 are all MOSFET switch tubes.

4. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The first switch tube S1 , the second switch tube S2 , the third switch tube S3 , and the fourth switch tube S4 all have parasitic diodes and parasitic capacitors.

5. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The first transformer T1 and the second transformer T2 are both planar transformers; the first leakage inductor L leak1 The magnetic is integrated in the first transformer T1, the second leakage inductor L leak2 The magnetics are integrated into the second transformer T2.

6. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The secondary side of the second transformer T2 has a center tap, and the emitter of the first switch tube Q1 is connected to the secondary side N of the second transformer T2. s1 The same-named ends are connected.

7. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The fifth diode D5, the sixth diode D6, the seventh diode D7 and the eighth diode D8 are all rectifier diodes, and the model is IDH15S120; the model of the twelfth diode D12 is 20CTH03.

8. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The fifth diode D5 , the sixth diode D6 , the seventh diode D7 and the eighth diode D8 all have parasitic capacitance.

9. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The device further includes a filter inductor L2 , one end of which is connected to the cathode of the ninth diode D9 , and the other end of which is connected to the first output capacitor C12 .

10. The DC-DC converter of the magnetic integrated foil bit hybrid circuit according to claim 1, characterized in that: The first power tube Q1 and the second power tube Q2 are both IGBT power tubes.

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