Conversion circuit based on multi-phase magnetic integrated transformer and transformer leakage inductance adjustment method

Abstract

The present invention belongs to the technical field of power conversion, and specifically relates to a conversion circuit based on a multi-phase magnetic integrated transformer and a transformer leakage inductance adjustment method, which aims to solve the problem that the resonant inductor and transformer in the traditional high-frequency resonant converter are large in size and high in loss, and the conventional magnetic integrated transformer cannot accurately design the leakage inductance. The present invention includes: an input filter circuit, a half-bridge switching circuit, a multi-phase transformer, a resonant circuit, a rectifier circuit and an output filter circuit, wherein the multi-phase transformer is a multi-phase magnetic integrated transformer, and the resonant inductor in the resonant circuit is the secondary parasitic leakage inductance of the multi-phase magnetic integrated transformer. The present invention adopts a multi-phase magnetic integrated transformer with a simple structure, small size, low cost, and a flexibly adjustable winding turn ratio, so that the multi-phase high-frequency converter has high power density, small size and low cost.

Description

Background Art

[0002] With the rapid development of renewable energy power generation and new energy vehicles, the requirements for performance indicators such as efficiency and power density of power electronic devices are also increasing. As an indispensable part of the power conversion system, the DC converter mainly completes the power conversion link between the DC bus of the power supply and the DC load, and is responsible for the conversion of voltage levels between the DC buses in the system. The conversion efficiency, power density and reliability of the DC converter are crucial to the performance of the power conversion system. High-frequency resonant soft switching circuits such as LLC and CLL have the advantages of simple circuit structure, low voltage stress of the switch tube, and can achieve zero voltage switching (ZVS) of the main switch tube and zero current switching (ZCS) of the secondary switch tube within the full load range, which are highly valued by the industry and academia.

[0003] When the input / output voltage of LLC, CLL and other circuits varies over a wide range, a larger resonant inductor is required to achieve a wide range of voltage gain. The use of additional discrete inductors can achieve more accurate circuit parameter design, but it will increase the size and cost of the converter. At the same time, the use of discrete inductors will also reduce the conversion efficiency of the system. Using transformer leakage inductance as a resonant inductor, such as a magnetically integrated transformer, can achieve higher power density without increasing the cost of the converter. However, conventional magnetically integrated transformers cannot accurately design leakage inductance, and often use a "winding-measurement-adjustment" method for repeated iterations, resulting in the inability to accurately and optimally design the converter parameters.

[0004] Therefore, how to accurately design the leakage inductance of the magnetic integrated transformer over a large range is one of the key issues in achieving the optimal design of high-frequency resonant soft switching circuits. Summary of the invention

[0005] In order to solve the above-mentioned problems in the prior art, namely, the resonant inductor and transformer in the traditional high-frequency resonant converter are large in size and high in loss, and the conventional magnetic integrated transformer cannot accurately design the leakage inductance, the present invention provides a conversion circuit based on a multi-phase magnetic integrated transformer, the conversion circuit includes an input filter circuit, a half-bridge switch circuit, a multi-phase transformer, a resonant circuit, a rectifier circuit and an output filter circuit, characterized in that the multi-phase transformer is a multi-phase magnetic integrated transformer;

[0006] The resonant circuit includes a resonant capacitor and a resonant inductor, and the resonant inductor is the secondary side parasitic leakage inductance of the multi-phase magnetic integrated transformer.

[0007] In some preferred embodiments, the connection relationship of the resonant capacitor is:

[0008] One end of the resonant capacitor is connected to the midpoint of the bridge arm of the half-bridge switch circuit, and the other end is connected to one end of the primary winding of the multi-phase magnetic integrated transformer;

[0009] The other end of the primary winding of the multi-phase magnetic integrated transformer is connected to the bridge arm grounding point of the half-bridge switching circuit.

[0010] In some preferred embodiments, the rectifier circuit is connected to the secondary windings of each phase of the multi-phase magnetic integrated transformer to form a multi-phase rectifier circuit;

[0011] The outputs of the multi-phase rectifier circuits are connected in parallel and then connected to the output filter circuit as one output; or the outputs of the multi-phase rectifier circuits are respectively connected to the corresponding output filter circuits as multiple outputs.

[0012] In some preferred embodiments, the multi-phase magnetic integrated transformer comprises a magnetic core, a primary winding and a multi-phase secondary winding;

[0013] The magnetic core comprises an upper magnetic core cover, a lower magnetic core cover, and a first magnetic core column, a second magnetic core column, and a third magnetic core side column between the upper magnetic core cover and the lower magnetic core cover, wherein the first magnetic core column, the second magnetic core column, and the third magnetic core column form a closed magnetic flux loop with the upper magnetic core cover and the lower magnetic core cover;

[0014] The number of the multi-phase secondary windings is 2N, including first n-phase secondary windings and second n-phase secondary windings, wherein 1≤n≤N;

[0015] The multi-phase secondary windings are respectively connected to one-phase branches of the secondary output of the multi-phase circuit;

[0016] Among them, the excitation inductance and secondary resonant inductance of the multi-phase magnetic integrated transformer are adjusted by the turns ratio of the primary winding and the secondary winding and the air gap sizes of the first magnetic core column, the second magnetic core column and the third magnetic core column.

[0017] In some preferred embodiments, the second magnetic core column is a magnetic core column between the first magnetic core column and the third magnetic core column or two magnetic core side columns on both sides of the first magnetic core column and the third magnetic core column.

[0018] In some preferred embodiments, the primary winding is wound on the first magnetic core column and the third magnetic core column respectively, and the number of turns of the primary winding wound on the first magnetic core column is the same as the number of turns of the primary winding wound on the third magnetic core column;

[0019] The first n-phase secondary winding is wound on the first magnetic core column, and the first n-phase secondary winding is wound in the same direction as the primary winding wound on the first magnetic core column; the second n-phase secondary winding is wound on the third magnetic core column, and the second n-phase secondary winding is wound in the opposite direction to the primary winding wound on the third magnetic core column;

[0020] The first n-phase secondary winding and the second n-phase secondary winding are arranged in mirror symmetry with respect to a center line of the second magnetic core column or a center line of the first magnetic core column and the third magnetic core column.

[0021] In some preferred embodiments, the multi-phase magnetic integrated transformer is a flat transformer, the first n-phase secondary winding and the second n-phase secondary winding are distributed on the top layer or the bottom layer of the PCB circuit board, the primary winding is distributed on the middle layer of the PCB circuit board, each phase winding is an arc surrounding the corresponding magnetic core column, the curvature of each arc winding is constrained by the transformer ratio, and the sum of the curvatures of each winding is not greater than

[0022] In some preferred embodiments, the currents in the windings with the same arc in the first n-phase secondary windings and the second n-phase secondary windings are the same in magnitude and have a phase difference of 180°.

[0023] In some preferred embodiments, during the switching cycle of the multi-phase magnetic integrated transformer, the circuit conduction relationship is:

[0024] In the positive half cycle of the switching cycle, the first n-phase secondary windings and the corresponding rectifier circuits are turned on, and the second n-phase secondary windings and the corresponding rectifier circuits are turned off;

[0025] In the negative half cycle of the switching cycle, the second n-phase secondary windings and the corresponding rectifier circuits are turned on, and the first n-phase secondary windings and the corresponding rectifier circuits are turned off;

[0026] The first n-phase secondary winding and the second n-phase secondary winding work alternately in the switching cycle of the multi-phase magnetic integrated transformer. The magnetic flux in the magnetic core of the multi-phase magnetic integrated transformer is unbalancedly distributed, and the magnetic flux generated by the primary winding is not completely coupled to the secondary winding, forming a secondary leakage inductance greater than a set threshold.

[0027] Another aspect of the present invention provides a method for adjusting the leakage inductance of a multi-phase magnetic integrated transformer in a conversion circuit based on a multi-phase magnetic integrated transformer. Based on the above-mentioned conversion circuit based on a multi-phase magnetic integrated transformer, the adjustment method includes:

[0028] Step S10, according to the turns ratio requirement n of the multi-phase magnetic integrated transformer, the number of turns of the primary winding wound on the first magnetic core column and the third magnetic core column is set to N1, and the number of turns of each phase of the multi-phase secondary winding is set to N2;

[0029] Step S20, recording the air gap magnetic resistance of the first magnetic core column and the third magnetic core column as R1, and recording the air gap magnetic resistance of the second magnetic core column as R2;

[0030] Step S30, obtaining the excitation inductance L according to the relationship between the inductance, current and voltage of the multi-phase magnetic integrated transformer m 、Primary leakage inductance L rp and secondary leakage inductance L rs A first adjustment relationship with the air gap magnetic resistance R1, the air gap magnetic resistance R2, the number of turns N1 of the primary winding and the number of turns N2 of the secondary winding;

[0031] Step S40, based on the excitation inductance L m and secondary leakage inductance L rs , calculate the ratio of the excitation inductance to the equivalent resonant inductance L n ;

[0032] Step S50, obtaining the cross-sectional area S1 of the first magnetic core column and the third magnetic core column, and the cross-sectional area S2 of the second magnetic core column, and calculating the air gap size l between the first magnetic core column and the third magnetic core column g1 And the air gap size l of the second magnetic core column g2 With the ratio L n , the number of turns of the primary winding N1, the excitation inductance L m The second adjustment relationship;

[0033] Step S60: adjusting the excitation inductance and leakage inductance of the multi-phase magnetic integrated transformer based on the first adjustment relationship and the second adjustment relationship.

[0034] Beneficial effects of the present invention:

[0035] (1) The present invention is based on a conversion circuit of a multi-phase magnetic integrated transformer, and uses the secondary leakage inductance of the multi-phase magnetic integrated transformer as a resonant inductor. The secondary side can adopt a multi-phase circuit output parallel structure to achieve soft switching of all switch tubes on the primary and secondary sides, and is suitable for applications with larger output currents. It can also be filtered separately as multi-channel outputs, and has the advantages of simple structure, small size, high efficiency, and flexible adaptability.

[0036] (2) The present invention is based on the multi-phase magnetic integrated transformer in the conversion circuit of the multi-phase magnetic integrated transformer. Through the principle of magnetic flux cancellation in the magnetic core cover, a magnetic core with three magnetic core columns (such as a conventional E-type magnetic core) is used to realize the integration of the multi-phase transformer. Compared with discrete multi-phase transformers, it has the advantages of small size, low cost and high efficiency.

[0037] (3) The present invention is based on a multi-phase magnetic integrated transformer in a conversion circuit of a multi-phase magnetic integrated transformer. A larger leakage inductance is achieved by generating an unbalanced magnetic flux distribution in the magnetic core. The number of winding turns and the air gap of the magnetic core can be adjusted to achieve precise design of the transformer's excitation inductance and leakage inductance, thereby solving the problem that the leakage inductance in conventional high-frequency transformers cannot be precisely designed. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0039] Figure 1 It is a schematic diagram of a power conversion circuit based on a two-phase magnetic integrated transformer in one embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0040] Figure 2 It is a schematic diagram of a CLL power conversion circuit with two-phase parallel output in the prior art;

[0041] Figure 3 It is a schematic diagram of the positive half cycle operation of the switching cycle of a CLL power conversion circuit with two-phase parallel output in the prior art;

[0042] Figure 4 It is a schematic diagram of the positive half cycle operation of the switching cycle of a power conversion circuit based on a two-phase magnetic integrated transformer in one embodiment of the conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0043] Figure 5 It is a structural schematic diagram of a multi-phase magnetic integrated transformer according to an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0044] Figure 6 It is a side sectional view of a multi-phase magnetic integrated transformer according to an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0045] Figure 7 It is a two-phase magnetic integrated transformer and circuit principle diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0046] Figure 8 It is a four-phase magnetic integrated transformer and circuit principle diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0047] Fig. 9 It is a six-phase magnetic integrated transformer and circuit principle diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0048] Fig.10 It is an eight-phase magnetic integrated transformer and circuit principle diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0049] Fig.11 It is a ten-phase magnetic integrated transformer and circuit principle diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0050] Fig.12 It is a twelve-phase magnetic integrated transformer and circuit principle diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0051] Fig.13 It is a six-phase magnetic integrated transformer with a turn ratio of 1:0.167 and a circuit schematic diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0052] Fig.14 It is a six-phase magnetic integrated transformer with a turn ratio of 1:0.167 and 1:0.33 and a circuit schematic diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0053] Fig.15 It is a four-phase magnetic integrated transformer with a turns ratio of 1:1 and a circuit schematic diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0054] Fig.16 It is an equivalent magnetic circuit diagram of a multi-phase magnetic integrated transformer according to an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention;

[0055] Fig.17 It is an equivalent magnetic circuit diagram of the positive half cycle of the switching period of a multi-phase magnetic integrated transformer according to one embodiment of the conversion circuit based on the multi-phase magnetic integrated transformer of the present invention;

[0056] Fig.18 It is an equivalent magnetic circuit diagram of the negative half cycle of the switching period of a multi-phase magnetic integrated transformer according to an embodiment of the conversion circuit of the multi-phase magnetic integrated transformer of the present invention. DETAILED DESCRIPTION

[0057] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0058] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0059] A conversion circuit based on a multi-phase magnetic integrated transformer of the present invention comprises an input filter circuit, a half-bridge switch circuit, a multi-phase transformer, a resonant circuit, a rectifier circuit and an output filter circuit;

[0060] The multiphase transformer is a multiphase magnetic integrated transformer;

[0061] The resonant circuit includes a resonant capacitor and a resonant inductor, and the resonant inductor is the secondary side parasitic leakage inductance of the multi-phase magnetic integrated transformer.

[0062] In order to more clearly illustrate the conversion circuit based on the multi-phase magnetic integrated transformer of the present invention, each module in the embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0063] The conversion circuit based on the multi-phase magnetic integrated transformer of the first embodiment of the present invention includes an input filter circuit, a half-bridge switch circuit, a multi-phase transformer, a resonant circuit, a rectifier circuit and an output filter circuit. Each module is described in detail as follows:

[0064] The multi-phase transformer is a multi-phase magnetic integrated transformer, the resonant circuit includes a resonant capacitor and a resonant inductor, and the resonant inductor is the secondary side parasitic leakage inductance of the multi-phase magnetic integrated transformer.

[0065] like Figure 1 As shown, it is a schematic diagram of a power conversion circuit based on a two-phase magnetic integrated transformer according to an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention, including an input filter circuit 41, a half-bridge switch circuit 42, a resonant capacitor 43, a two-phase transformer 44, a rectifier circuit 45 and an output filter circuit 46. Among them, the two-phase transformer 44 is a two-phase magnetic integrated transformer corresponding to an embodiment of a multi-phase magnetic integrated transformer.

[0066] The resonant capacitor 43 and the resonant inductor L sra1 , L sra2 , L srb1 , L srb2 A resonant circuit is formed to transfer energy and realize soft switching of the switching device. The resonant inductor is not an external inductor, but the secondary parasitic leakage inductance of the two-phase magnetic integrated transformer.

[0067] One end of the resonant capacitor is connected to the midpoint of the bridge arm of the half-bridge switching circuit, and the other end is connected to one end of the primary winding of the multi-phase magnetic integrated transformer. The other end of the primary winding of the multi-phase magnetic integrated transformer is connected to the grounding point of the bridge arm of the half-bridge switching circuit.

[0068] Attached Figure 1It can be seen that one end of the resonant capacitor 43 is connected to the midpoint of the bridge arm of the half-bridge switch circuit 42, and the other end is connected to one end of the primary winding of the two-phase magnetic integrated transformer 44, and the other end of the primary winding of the two-phase magnetic integrated transformer 44 is connected to the grounding point of the bridge arm of the half-bridge switch circuit 42.

[0069] In addition, the outputs of the multi-phase rectifier circuits are connected in parallel and then connected to the output filter circuit as one output; or the outputs of the multi-phase rectifier circuits are respectively connected to the corresponding output filter circuits as multiple outputs.

[0070] Attached Figure 1 What is given in the figure is a schematic diagram of a two-phase output in parallel structure, where the rectifier circuit 45 is connected to the A-phase secondary winding and the B-phase secondary winding of the two-phase magnetic integrated transformer 44 to form an A-phase rectifier circuit and a B-phase rectifier circuit; the outputs of the A-phase rectifier circuit and the B-phase rectifier circuit are connected in parallel to the output filter circuit 46.

[0071] The unbalanced distribution of magnetic flux in the two-phase magnetic integrated transformer in the above embodiment is the key to realize the accurate design of the excitation inductance and leakage inductance of the present invention, which is formed by the different working modes of the CLL power conversion circuit. Figure 2 As shown in FIG. 1 , it is a schematic diagram of a CLL power conversion circuit with two-phase parallel output in the prior art. The winding method of the two-phase secondary windings is exactly the same, that is, they have the same terminals with the same name, so their working modes in the positive and negative half cycles of the switching cycle are exactly the same, as shown in FIG. Figure 3 As shown, it is a schematic diagram of the positive half cycle of the switching cycle of the CLL power conversion circuit with two phases in parallel output in the prior art. In the positive half cycle, S S1 and S S3 Open, in the negative half cycle S S2 and S S4 is turned on, so its flux distribution is balanced, that is, a larger leakage inductance cannot be achieved through flux imbalance.

[0072] In the power conversion circuit based on the two-phase magnetic integrated transformer of the present invention, the winding methods of the two-phase secondary windings are opposite, that is, they have opposite same-name terminals. The currents in the A-phase rectifier circuit and the B-phase rectifier circuit are the same in magnitude and 180° out of phase with each other.

[0073] like Figure 4 As shown, it is a schematic diagram of the positive half cycle operation of the switching cycle of the power conversion circuit based on the two-phase magnetic integrated transformer of an embodiment of the conversion circuit based on the multi-phase magnetic integrated transformer of the present invention. In the positive half cycle, S S1 and S S2 Open, in the negative half cycle S S3 and S S4It is turned on, resulting in an imbalance in the magnetic flux distribution. In the positive half of the switching cycle, energy is provided to the load from the input voltage through the half-bridge switching circuit, the resonant circuit, the two-phase transformer, the A-phase rectifier circuit and the filter circuit; in the negative half of the switching cycle, energy is provided to the load from the input voltage through the half-bridge switching circuit, the resonant circuit, the two-phase transformer, the B-phase rectifier circuit and the filter circuit.

[0074] like Figure 5 As shown, it is a structural schematic diagram of a multi-phase magnetic integrated transformer of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention. The multi-phase magnetic integrated transformer includes a magnetic core, a primary winding 106 and a multi-phase secondary winding:

[0075] The magnetic core includes an upper magnetic core cover 101, a lower magnetic core cover 102, and a first magnetic core column 103, a second magnetic core column 104 and a third magnetic core column 105 between the upper magnetic core cover and the lower magnetic core cover. The first magnetic core column 103, the second magnetic core column 104 and the third magnetic core column 105 form a closed magnetic flux loop with the upper magnetic core cover 101 and the lower magnetic core cover 102.

[0076] The second magnetic core column 104 may be a magnetic core column arranged between the first magnetic core column 103 and the third magnetic core column 105 , or the second magnetic core column 104 may be replaced by magnetic core side columns on both sides of the first magnetic core column 103 and the third magnetic core column 105 .

[0077] The primary winding 107 is wound around the first magnetic core column 103 and the third magnetic core column 105 respectively, and the number of turns wound around the first magnetic core column 103 and the third magnetic core column 105 is the same.

[0078] The number of multi-phase secondary windings is 2N, including a first n-phase secondary winding 106 and a second n-phase secondary winding 108, wherein 1≤n≤N.

[0079] The first n-phase secondary winding 106 is wound on the first magnetic core column 103, and the winding direction of the first n-phase secondary winding 106 is consistent with that of the primary winding 107 wound on the first magnetic core column 103. The second n-phase secondary winding 108 is wound on the third magnetic core column 105, and the winding direction of the second n-phase secondary winding 108 is opposite to that of the primary winding 107 wound on the third magnetic core column 105.

[0080] When the second magnetic core column 104 exists, the first n-phase secondary winding 106 and the second n-phase secondary winding 108 are arranged in a mirror-symmetrical manner with respect to the second magnetic core column 104; when a magnetic core side column is used to replace the second magnetic core column 104, the first n-phase secondary winding 106 and the second n-phase secondary winding 108 are arranged in a mirror-symmetrical manner with respect to the center line of the first magnetic core column 103 and the third magnetic core column 105.

[0081] like Figure 6As shown, it is a side sectional view of a multiphase magnetic integrated transformer according to an embodiment of a conversion circuit based on a multiphase magnetic integrated transformer of the present invention. The multiphase magnetic integrated transformer is a flat transformer. The first n-phase secondary winding 106 and the second n-phase secondary winding 108 are distributed on the top layer or the lower layer of the PCB circuit board (the places shown in 201, 203, 204, and 205 in the attached figure), and the primary winding 107 is distributed on the middle layer of the PCB circuit board (the place shown in 202 in the attached figure). Each phase winding is an arc surrounding the corresponding magnetic core column. The curvature of each arc winding is constrained by the transformation ratio of the transformer (that is, the curvature of each arc winding is determined by the transformation ratio of the transformer), and the sum of the curvatures of each winding is not greater than

[0082] The currents in the windings with the same arc in the first n-phase secondary winding 106 and the second n-phase secondary winding 108 are the same in magnitude and have a phase difference of 180°.

[0083] The multi-phase secondary windings are respectively connected to one-phase branches (rectifier circuits) of the secondary output of the multi-phase circuit, and the output side of the rectifier circuit is connected to one or more common output terminals to form a single-port or multi-port output circuit.

[0084] The excitation inductance and secondary resonant inductance of the multi-phase magnetic integrated transformer are adjusted by the turns ratio of the primary winding 107 and the secondary windings 106 and 108 and the air gap sizes of the first magnetic core column 103 , the second magnetic core column 104 and the third magnetic core column 105 .

[0085] During the switching cycle of the multi-phase magnetic integrated transformer, the circuit conduction relationship is:

[0086] In the positive half cycle of the switching cycle, the first n-phase secondary winding 106 and the corresponding rectifier circuit are turned on, and the second n-phase secondary winding 108 and the corresponding rectifier circuits are not turned on;

[0087] In the negative half cycle of the switching cycle, the second n-phase secondary winding 108 and the corresponding rectifier circuit are turned on, and the first n-phase secondary winding 106 and the corresponding rectifier circuits are not turned on;

[0088] The first n-phase secondary winding 106 and the second n-phase secondary winding 108 work alternately in the switching cycle of the multi-phase magnetic integrated transformer. The magnetic flux in the magnetic core of the multi-phase magnetic integrated transformer is unbalancedly distributed, and the magnetic flux generated by the primary winding 107 is not completely coupled to the secondary side, forming a secondary leakage inductance (larger leakage inductance) greater than a set threshold, which is the leakage inductance that subsequently serves as a replacement for the resonant inductance in the resonant circuit.

[0089] Figure 7 to Figure 12 This is a circuit principle diagram and a structural diagram of the magnetic integrated transformer of the present invention under different secondary phase numbers. To simplify the analysis, the number of turns of the primary winding on the first magnetic core column and the third magnetic core column is set to 1 turn.

[0090] like Figure 7 As shown, a two-phase magnetic integrated transformer and a circuit schematic diagram of an embodiment of the conversion circuit based on a multi-phase magnetic integrated transformer of the present invention, the upper part is a circuit schematic diagram of the two-phase magnetic integrated transformer, and the lower part is a winding structure diagram of the two-phase secondary winding in the magnetic core, wherein the left side is the first-phase secondary winding, and the right side is the second-phase secondary winding. The first-phase secondary winding and the second-phase secondary winding are both distributed on the top layer of the PCB, and the number of turns is 1 turn, so the turns ratio of each phase of the transformer is 1:1. In actual work, in the positive half cycle of the switching cycle, the first-phase secondary winding is turned on with SR1, and in the negative half cycle of the switching cycle, the second-phase secondary winding is turned on with SR2. The first-phase secondary winding and the second-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0091] like Figure 8 As shown, a four-phase magnetic integrated transformer and a circuit schematic diagram of an embodiment of the conversion circuit based on a multi-phase magnetic integrated transformer of the present invention, the upper part is a circuit schematic diagram of the four-phase magnetic integrated transformer, and the lower part is a winding structure diagram of the four-phase secondary winding in the magnetic core. The first 2-phase secondary winding and the second 2-phase secondary winding are both distributed on the top layer of the PCB, and the number of turns is 0.5 turns, so the turns ratio of each phase of the transformer is 1:0.5. In actual work, in the positive half cycle of the switching cycle, the first 2-phase secondary winding is turned on with SR1 and SR2, and in the negative half cycle of the switching cycle, the second 2-phase secondary winding is turned on with SR3 and SR4. The first 2-phase secondary winding and the second 2-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0092] like Fig. 9 As shown, a six-phase magnetic integrated transformer and a circuit schematic diagram of an embodiment of the conversion circuit based on a multi-phase magnetic integrated transformer of the present invention, the upper part is a circuit schematic diagram of the six-phase magnetic integrated transformer, and the lower part is a winding structure diagram of the six-phase secondary winding in the magnetic core. The first three-phase secondary winding and the second three-phase secondary winding are distributed on the top layer of the PCB, and the number of turns is 0.33 turns, so the turns ratio of each phase of the transformer is 1:0.33. In actual work, in the positive half cycle of the switching cycle, the first three-phase secondary winding is turned on with SR1~SR3, and in the negative half cycle of the switching cycle, the second three-phase secondary winding is turned on with SR4~SR6. The first three-phase secondary winding and the second three-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0093] like Fig.10As shown, an eight-phase magnetic integrated transformer and circuit schematic diagram of an embodiment of the conversion circuit based on a multi-phase magnetic integrated transformer of the present invention, the upper part is the circuit schematic diagram of the eight-phase magnetic integrated transformer, and the lower part is the winding structure diagram of the eight-phase secondary winding in the magnetic core. The first 4-phase secondary winding and the second 4-phase secondary winding are all distributed on the top layer of the PCB, and the number of turns is 0.25 turns, so the turns ratio of each phase of the transformer is 1:0.25. In actual work, in the positive half cycle of the switching cycle, the first 4-phase secondary winding is turned on with SR1~SR4, and in the negative half cycle of the switching cycle, the second 4-phase secondary winding is turned on with SR5~SR8. The first 4-phase secondary winding and the second 4-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0094] like Fig.11 As shown, a ten-phase magnetic integrated transformer and a circuit schematic diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention, the upper part is a circuit schematic diagram of a ten-phase magnetic integrated transformer, and the lower part is a winding structure diagram of a ten-phase secondary winding in a magnetic core, the first 5-phase secondary winding and the second 5-phase secondary winding are both distributed on the top layer of the PCB, and the number of turns is 0.2 turns, so the turns ratio of each phase of the transformer is 1:0.2. In actual work, in the positive half cycle of the switching cycle, the first 5-phase secondary winding is turned on with SR1~SR5, and in the negative half cycle of the switching cycle, the second 5-phase secondary winding is turned on with SR6~SR10. The first 5-phase secondary winding and the second 5-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0095] like Fig.12 As shown, a twelve-phase magnetic integrated transformer and a circuit schematic diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention, the upper part is a circuit schematic diagram of the twelve-phase magnetic integrated transformer, and the lower part is a winding structure diagram of the twelve-phase secondary winding in the magnetic core. The first six-phase secondary winding and the second six-phase secondary winding are both distributed on the top layer of the PCB, and the number of turns is 0.167 turns, so the turns ratio of each phase of the transformer is 1:0.167. In actual work, in the positive half cycle of the switching cycle, the first six-phase secondary winding is turned on with SR1~SR6, and in the negative half cycle of the switching cycle, the second six-phase secondary winding is turned on with SR7~SR12. The first six-phase secondary winding and the second six-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0096] In the above embodiments, the sum of the arcs of the multi-phase secondary windings is 360 degrees. In practical applications, the arc of the secondary winding of each phase can be flexibly adjusted according to different primary-secondary turns ratios.

[0097] The principle diagram and winding structure of a magnetic integrated transformer with more phases can also be deduced by referring to the above embodiment, and the present invention will not be described in detail here.

[0098] like Fig.13 As shown, a six-phase magnetic integrated transformer with a turn ratio of 1:0.167 and a circuit schematic diagram of an embodiment of the conversion circuit based on a multi-phase magnetic integrated transformer of the present invention is shown. The upper part is a circuit schematic diagram of the six-phase magnetic integrated transformer, and the lower part is a winding structure diagram of the six-phase secondary winding in the magnetic core. The first three-phase secondary winding and the second three-phase secondary winding are all distributed on the top layer of the PCB, and the number of turns is 0.167 turns. Then, the turn ratio of each phase of the transformer is 1:0.167. In actual work, in the positive half cycle of the switching cycle, the first three-phase secondary winding is turned on with SR1~SR3, and in the negative half cycle of the switching cycle, the second three-phase secondary winding is turned on with SR4~SR6. The first three-phase secondary winding and the second three-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0099] like Fig.14 As shown, a six-phase magnetic integrated transformer and a circuit schematic diagram with a turn ratio of 1:0.167 and 1:0.33 according to an embodiment of the conversion circuit of the present invention based on a multi-phase magnetic integrated transformer are shown. The arc of each phase of the multi-phase secondary winding is flexibly adjusted according to the specific application. The upper part is the circuit schematic diagram of the six-phase magnetic integrated transformer, and the lower part is the winding structure diagram of the six-phase secondary winding in the magnetic core. The first two-phase secondary winding and the second two-phase secondary winding are both distributed on the top layer of the PCB, wherein the turns of the two-phase secondary winding are 0.33 turns and 0.167 turns respectively, and the corresponding transformer ratio is 1:0.33 and 1:0.167, so the two-phase secondary winding can output two different voltages after passing through the rectifier circuit, which can be applied to a multi-port converter. In actual work, in the positive half cycle of the switching cycle, the first two-phase secondary winding is turned on with SR1 and SR2, and in the negative half cycle of the switching cycle, the second two-phase secondary winding is turned on with SR3 and SR4. The first 2-phase secondary winding and the second 2-phase secondary winding have the same current magnitude and a phase difference of 180 degrees in one switching cycle.

[0100] In addition, a third N-phase secondary winding, a fourth N-phase secondary winding and a corresponding rectifier circuit are placed on the top or bottom layer of the PCB circuit board, which are symmetrical to the first N-phase secondary winding and the second N-phase secondary winding, respectively, so that the number of secondary multi-phase circuits reaches 4N, which can improve the power capacity and power density of the circuit, wherein the first N-phase secondary winding and the third N-phase secondary winding located on the first magnetic core column have the same working mode, and the second N-phase secondary winding and the fourth N-phase secondary winding located on the third magnetic core column have the same working mode.

[0101] like Fig.15As shown, a four-phase magnetic integrated transformer with a turn ratio of 1:1 and a circuit schematic diagram of an embodiment of a conversion circuit based on a multi-phase magnetic integrated transformer of the present invention is shown. The upper part is a circuit schematic diagram of a four-phase magnetic integrated transformer, and the lower part is a winding structure diagram of a four-phase secondary winding in a magnetic core. The first-phase secondary winding and the second-phase secondary winding are both distributed on the top layer of the PCB, and the third-phase secondary winding and the fourth-phase secondary winding are both distributed on the bottom layer of the PCB, and the number of turns is 1 turn, so the turn ratio of each phase of the transformer is 1:1. It can be seen that by using the same winding structure, by adding the third-phase secondary winding and the fourth-phase secondary winding on the bottom layer of the PCB, Fig.11 The secondary winding phase number of the four-phase magnetic integrated transformer shown reaches Figure 8 The current of the first-phase secondary winding and the third-phase secondary winding is the same as that of the four-phase magnetic integrated transformer shown in FIG. In actual operation, in the positive half cycle of the switching cycle, the first-phase secondary winding and the third-phase secondary winding are connected with SR1 and SR2, and in the negative half cycle of the switching cycle, the second-phase secondary winding and the fourth-phase secondary winding are connected with SR3 and SR4. The current of the first-phase secondary winding and the third-phase secondary winding is the same as that of the second-phase secondary winding and the fourth-phase secondary winding in one switching cycle, and the phase difference is 180 degrees.

[0102] A method for adjusting leakage inductance of a multi-phase magnetic integrated transformer in a conversion circuit based on a multi-phase magnetic integrated transformer according to a second embodiment of the present invention is based on the above-mentioned conversion circuit based on a multi-phase magnetic integrated transformer, and the adjustment method includes:

[0103] Step S10, according to the turns ratio requirement n of the multi-phase magnetic integrated transformer, the number of turns of the primary winding wound on the first magnetic core column and the third magnetic core column is set to N1, and the number of turns of each phase of the multi-phase secondary winding is set to N2.

[0104] In step S20, the air gap magnetic resistance of the first magnetic core column and the third magnetic core column is recorded as R1, and the air gap magnetic resistance of the second magnetic core column is recorded as R2.

[0105] like Fig.16 As shown, it is an equivalent magnetic circuit diagram of a multi-phase magnetic integrated transformer according to an embodiment of the conversion circuit of the multi-phase magnetic integrated transformer of the present invention, ignoring the magnetic core reluctance, assuming that the leakage flux in the air is very small and negligible, and in order to simplify the analysis, the curvature of the multi-phase secondary winding is set to be the same. The air gaps on the first magnetic core column 103 and the third magnetic core column 105 are the same, and their equivalent reluctance is R1. The air gaps on the second magnetic core column 104 and the first magnetic core column 103 and the third magnetic core column 105 are different, and their equivalent reluctance is R2. The primary current of the multi-phase magnetic integrated transformer is I p , the secondary current is I s The primary winding voltage on the first magnetic core column 103 is V p1 , the primary winding voltage on the second magnetic core column 104 is V p2 , the primary winding voltage on the third magnetic core column 105 is Vp3 The magnetic flux on the first magnetic core column 103 is Φ a , the magnetic flux on the second magnetic core column 104 is Φ b , the magnetic flux of the third magnetic core column 105 is Φ c .

[0106] like Fig.17 and Fig.18 As shown, they are equivalent magnetic circuit diagrams of the positive half cycle and the negative half cycle of the switching cycle of the multi-phase magnetic integrated transformer of one embodiment of the conversion circuit based on the multi-phase magnetic integrated transformer of the present invention. Taking the positive half cycle as an example, at this time, the first n-phase secondary winding 106 and the rectifier circuits connected to each other are turned on, and the magnetic fluxes in the magnetic core are shown in formula (1):

[0107]

[0108] According to Faraday's formula, the voltage of the primary winding 106 of the multi-phase magnetic integrated transformer is V p , the voltage of the secondary winding of one phase is V s , the total voltage of the multi-phase secondary winding is V ds , then V p and V ds As shown in formula (2):

[0109]

[0110] The turns ratio of the magnetic integrated transformer is shown in formula (3):

[0111]

[0112] Step S30, obtaining the excitation inductance L according to the relationship between the inductance, current and voltage of the multi-phase magnetic integrated transformer m 、Primary leakage inductance L rp and secondary leakage inductance L rs The first adjustment relationship between the air gap magnetic resistance R1, the air gap magnetic resistance R2, the number of turns N1 of the primary winding and the number of turns N2 of the secondary winding is as shown in formula (4):

[0113]

[0114] Step S40, based on the excitation inductance L m and secondary leakage inductance L rs , calculate the ratio of the excitation inductance to the equivalent resonant inductance L n , as shown in formula (5):

[0115]

[0116] Step S50, obtaining the cross-sectional area S1 of the first magnetic core column and the third magnetic core column, and the cross-sectional area S2 of the second magnetic core column, and calculating the air gap size l between the first magnetic core column and the third magnetic core column g1 And the air gap size l of the second magnetic core column g2 With the ratio L n , the number of turns of the primary winding N1, the excitation inductance L m The second adjustment relationship is shown in formula (6):

[0117]

[0118] Step S60: adjusting the excitation inductance and leakage inductance of the multi-phase magnetic integrated transformer based on the first adjustment relationship and the second adjustment relationship.

[0119] From the above formula, we can know that the excitation inductance L m , secondary resonant inductance (i.e. secondary leakage inductance L rs ) can be adjusted by adjusting the number of turns N1, N2 and the air gap l g1 , l g2 To make accurate calculations and adjustments.

[0120] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the method described above can refer to the corresponding process in the aforementioned system embodiment, and will not be repeated here.

[0121] It should be noted that the conversion circuit based on the multi-phase magnetic integrated transformer and the transformer leakage inductance adjustment method provided in the above embodiment are only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in the embodiments of the present invention are only for distinguishing the modules or steps, and are not regarded as improper limitations of the present invention.

[0122] A device according to a third embodiment of the present invention includes:

[0123] at least one processor; and

[0124] a memory communicatively connected to at least one of the processors; wherein,

[0125] The memory stores instructions executable by the processor, and the instructions are used to be executed by the processor to implement the above-mentioned method for adjusting the leakage inductance of a multi-phase magnetic integrated transformer in a conversion circuit based on a multi-phase magnetic integrated transformer.

[0126] A computer-readable storage medium according to a fourth embodiment of the present invention stores computer instructions, and the computer instructions are used to be executed by the computer to implement the above-mentioned method for adjusting the leakage inductance of a multi-phase magnetic integrated transformer in a conversion circuit based on a multi-phase magnetic integrated transformer.

[0127] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process and related instructions of the storage device and processing device described above can refer to the corresponding process in the aforementioned method embodiment and will not be repeated here.

[0128] Those skilled in the art should be able to appreciate that the modules and method steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, computer software or a combination of the two, and the programs corresponding to the software modules and method steps can be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disks, removable disks, CD-ROMs, or any other form of storage medium known in the technical field. In order to clearly illustrate the interchangeability of electronic hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are performed in electronic hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0129] The terms "first", "second", etc. are used to distinguish similar objects rather than to describe or indicate a particular order or sequence.

[0130] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0131] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A conversion circuit based on a multi-phase magnetic integrated transformer, It is characterized in that The conversion circuit comprises an input filter circuit, a half-bridge switch circuit, a multi-phase transformer, a resonant circuit, a rectifier circuit and an output filter circuit, wherein the multi-phase transformer is a multi-phase magnetic integrated transformer; The resonant circuit includes a resonant capacitor and a resonant inductor, and the resonant inductor is the secondary side parasitic leakage inductance of the multi-phase magnetic integrated transformer; The multi-phase magnetic integrated transformer comprises a magnetic core, a primary winding and a multi-phase secondary winding; The magnetic core comprises an upper magnetic core cover, a lower magnetic core cover, and a first magnetic core column, a second magnetic core column, and a third magnetic core side column between the upper magnetic core cover and the lower magnetic core cover, wherein the first magnetic core column, the second magnetic core column, and the third magnetic core column form a closed magnetic flux loop with the upper magnetic core cover and the lower magnetic core cover; The number of the multi-phase secondary windings is 2N, including first n-phase secondary windings and second n-phase secondary windings, wherein 1≤n≤N; The multi-phase secondary windings are respectively connected to one-phase branches of the secondary output of the multi-phase circuit; Among them, the excitation inductance and secondary resonant inductance of the multi-phase magnetic integrated transformer are adjusted by the turns ratio of the primary winding and the secondary winding and the air gap sizes of the first magnetic core column, the second magnetic core column and the third magnetic core column.

2. The conversion circuit based on the multi-phase magnetic integrated transformer according to claim 1, It is characterized in that The connection relationship of the resonant capacitor is: One end of the resonant capacitor is connected to the midpoint of the bridge arm of the half-bridge switch circuit, and the other end is connected to one end of the primary winding of the multi-phase magnetic integrated transformer; The other end of the primary winding of the multi-phase magnetic integrated transformer is connected to the bridge arm grounding point of the half-bridge switching circuit.

3. The conversion circuit based on the multi-phase magnetic integrated transformer according to claim 2, It is characterized in that The rectifier circuit is connected to the secondary windings of each phase of the multi-phase magnetic integrated transformer to form a multi-phase rectifier circuit; The outputs of the multi-phase rectifier circuits are connected in parallel and then connected to the output filter circuit as one output; or the outputs of the multi-phase rectifier circuits are respectively connected to the corresponding output filter circuits as multiple outputs.

4. The conversion circuit based on a multi-phase magnetic integrated transformer according to claim 1, It is characterized in that The second magnetic core column is a magnetic core column between the first magnetic core column and the third magnetic core column or two magnetic core side columns on both sides of the first magnetic core column and the third magnetic core column.

5. The conversion circuit based on a multi-phase magnetic integrated transformer according to claim 1 or 4, It is characterized in that The primary winding is wound on the first magnetic core column and the third magnetic core column respectively, and the number of turns of the primary winding wound on the first magnetic core column is the same as the number of turns of the primary winding wound on the third magnetic core column; The first n-phase secondary winding is wound on the first magnetic core column, and the first n-phase secondary winding is wound in the same direction as the primary winding wound on the first magnetic core column; the second n-phase secondary winding is wound on the third magnetic core column, and the second n-phase secondary winding is wound in the opposite direction to the primary winding wound on the third magnetic core column; The first n-phase secondary winding and the second n-phase secondary winding are arranged in mirror symmetry with respect to a center line of the second magnetic core column or a center line of the first magnetic core column and the third magnetic core column.

6. The conversion circuit based on the multi-phase magnetic integrated transformer according to claim 5, It is characterized in that The multi-phase magnetic integrated transformer is a flat transformer, the first n-phase secondary winding and the second n-phase secondary winding are distributed on the top layer or the bottom layer of the PCB circuit board, the primary winding is distributed on the middle layer of the PCB circuit board, each phase winding is an arc around the corresponding magnetic core column, the curvature of each arc winding is constrained by the transformer ratio, and the sum of the curvatures of each winding is not greater than 7. The conversion circuit based on the multi-phase magnetic integrated transformer according to claim 6, It is characterized in that The currents in the windings with the same arc in the first n-phase secondary windings and the second n-phase secondary windings are the same in magnitude and have a phase difference of 180°.

8. The conversion circuit based on a multi-phase magnetic integrated transformer according to claim 1, It is characterized in that During the switching cycle of the multi-phase magnetic integrated transformer, the circuit conduction relationship is: In the positive half cycle of the switching cycle, the first n-phase secondary windings and the corresponding rectifier circuits are turned on, and the second n-phase secondary windings and the corresponding rectifier circuits are turned off; In the negative half cycle of the switching cycle, the second n-phase secondary windings and the corresponding rectifier circuits are turned on, and the first n-phase secondary windings and the corresponding rectifier circuits are turned off; The first n-phase secondary winding and the second n-phase secondary winding work alternately in the switching cycle of the multi-phase magnetic integrated transformer. The magnetic flux in the magnetic core of the multi-phase magnetic integrated transformer is unbalancedly distributed, and the magnetic flux generated by the primary winding is not completely coupled to the secondary winding, forming a secondary leakage inductance greater than a set threshold.

9. A method for adjusting leakage inductance of a multi-phase magnetic integrated transformer in a conversion circuit based on a multi-phase magnetic integrated transformer, It is characterized in that Based on the conversion circuit based on the multi-phase magnetic integrated transformer according to any one of claims 1 to 8, the adjustment method comprises: Step S10: according to the turn ratio requirement n of the multi-phase magnetic integrated transformer, the number of turns of the primary winding wound on the first magnetic core column and the third magnetic core column is set to N. 1 , the number of turns of each phase of the multi-phase secondary winding is N 2 ; Step S20: record the air gap magnetic resistance of the first magnetic core column and the third magnetic core column as R 1 , the air gap reluctance of the second core column is recorded as R 2 ; Step S30, obtaining the excitation inductance L according to the relationship between the inductance, current and voltage of the multi-phase magnetic integrated transformer m 、Primary leakage inductance L rp and secondary leakage inductance L rs and air gap reluctance R 1 , air gap reluctance R 2 、N turns of the primary winding 1 and the number of turns of the secondary winding N 2 The first adjustment relationship; Step S40, based on the excitation inductance L m and secondary leakage inductance L rs , calculate the ratio of the excitation inductance to the equivalent resonant inductance L n ; Step S50, obtaining the cross-sectional area S of the first magnetic core column and the third magnetic core column 1 , the cross-sectional area of ​​the second magnetic core column S 2 , calculate the air gap size l between the first and third magnetic core columns g1 And the air gap size l of the second magnetic core column g2 With the ratio L n 、N turns of the primary winding 1 , Excitation inductance L m The second adjustment relationship; Step S60: adjusting the excitation inductance and leakage inductance of the multi-phase magnetic integrated transformer based on the first adjustment relationship and the second adjustment relationship.

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