Half-turn winding transformer, circuit topology and power device

Abstract

The invention discloses a half-turn winding transformer, a circuit topology and a power device. The half-turn winding transformer comprises a magnetic core, two high-voltage windings and four low-voltage windings, the magnetic core comprises two magnetic substrates and at least three magnetic columns, and the at least three magnetic columns are arranged in a line. According to the half-turn winding transformer, the step-down ratio between various input voltages and output voltages of the intermediate bus conversion device can be achieved, application of different output voltage requirements is met, and on the other hand, the loss of the transformer is reduced and the size of the transformer is reduced by designing the winding mode and the device layout of the transformer.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-frequency power supplies, and particularly relates to a half-turn winding transformer, a circuit topology, and a power device. Background Art

[0002] With the development of artificial intelligence, the power requirements of artificial intelligence data processing chips, such as CPUs, GPUs, TPUs, etc. (collectively referred to as xPUs), are getting higher and higher, resulting in a significant increase in the power of servers, and the supply voltage of server motherboards has risen from 12V to 54V. In applications where the supply voltage of server motherboards is 54V, a two-stage buck conversion circuit architecture has gradually become mainstream.

[0003] The intermediate bus conversion device in the two-stage buck conversion circuit architecture is a conversion device used to achieve voltage conversion between the input bus and the output bus, including a buck ratio between the input voltage and the output voltage of 4:1, 8:1, or 12:1, etc. With the diversification of application requirements, the requirements for the output voltage of the intermediate bus conversion device are also becoming more diverse. The present invention proposes a circuit topology and a half-turn transformer; the low-voltage winding of the transformer is 0.5 turns, and the high-voltage winding is (N - 0.5) turns, and a transformer winding winding method and a component layout diagram are proposed, so that the circuit topology can not only meet the requirements of various output voltages, but also obtain the advantages of low transformer loss and overall machine loss, high product efficiency, and small volume. Summary of the Invention

[0004] In view of this, one of the objectives of the present invention is to provide a half-turn winding transformer, including a magnetic core and windings, the windings including a first high-voltage winding, a second high-voltage winding, a first low-voltage winding combination, and a second low-voltage winding combination; the magnetic core includes two magnetic substrates, two side columns, and a middle column, the two side columns and a middle column are arranged between the two magnetic substrates, the two side columns and a middle column are arranged in the same direction, and the middle column is arranged between the two side columns; the two channels between the two side columns and the middle column are respectively a first channel and a second channel;

[0005] The magnetic core includes a first side surface, a second side surface, a third side surface, and a fourth side surface, the first side surface and the third side surface are opposite, the second side surface and the fourth side surface are opposite, and both the first channel and the second channel penetrate the second side surface and the fourth side surface;

[0006] Each of the windings includes a first end and a second end, and the first end and the second end of each high-voltage winding are arranged adjacent to the same side surface of the magnetic core; the second end of the first low-voltage winding combination and the first end of the second low-voltage winding combination are both arranged adjacent to the fourth side surface of the magnetic core, and the first end of the first low-voltage winding combination and the second end of the second low-voltage winding combination are both arranged adjacent to the second side surface of the magnetic core;

[0007] Each of the low-voltage winding combinations includes two low-voltage windings, and the two low-voltage windings in each low-voltage winding combination respectively pass through the first channel and the second channel; the first high-voltage winding sequentially passes through the second side surface, the first channel, and the fourth side surface from the first end to the second end; the second high-voltage winding sequentially passes through the fourth side surface, the second channel, and the second side surface from the first end to the second end.

[0008] Preferably, the voltage waveforms at both ends of the two low-voltage windings passing through the same channel are out of phase by 180 degrees; the voltage waveforms at both ends of the two low-voltage windings within the same low-voltage winding combination are out of phase by 180 degrees.

[0009] Preferably, the first high-voltage winding first passes through the second side surface from the first end to the second end, then passes through the first channel, winds around the middle column for at least one turn, and finally passes through the fourth side surface; the second high-voltage winding first passes through the fourth side surface from the first end to the second end, then passes through the second channel, winds around the middle column for at least one turn, and finally passes through the second side surface.

[0010] Preferably, in the first channel, the fundamental waves flowing through the high-voltage winding and the fundamental waves flowing through the two low-voltage windings are positive and negative to each other and cancel each other out; in the second channel, the fundamental waves flowing through the high-voltage winding and the fundamental waves flowing through the two low-voltage windings are positive and negative to each other and cancel each other out.

[0011] Another object of the present invention is to provide a circuit topology, including an input positive terminal, an input negative terminal, an output positive terminal, an input capacitor, an output capacitor, a high-voltage side circuit, and a low-voltage side circuit. The input capacitor is connected across the input positive terminal and the input negative terminal, the high-voltage side circuit is connected across the input positive terminal and the output positive terminal, and the low-voltage side circuit is connected across the output positive terminal and the input negative terminal; the low-voltage side circuit is a center-tapped rectifier circuit, and the low-voltage side circuit includes a first low-voltage winding combination and a first synchronous rectifier switch combination. The first low-voltage winding combination includes a first low-voltage winding and a second low-voltage winding, and the first synchronous rectifier switch combination includes a first synchronous rectifier switch and a second synchronous rectifier switch; the first low-voltage winding and the first synchronous rectifier switch are connected in series across the output positive terminal and the input negative terminal, and the second low-voltage winding and the second synchronous rectifier switch are connected in series across the output positive terminal and the input negative terminal; the output capacitor is connected across the output positive terminal and the input negative terminal.

[0012] Preferably, the high-voltage side circuit includes a switch bridge arm, a capacitor bridge arm, and a high-voltage side winding; the high-voltage side winding is connected across the midpoints of the switch bridge arm and the capacitor bridge arm; the switch bridge arm includes an upper switch and a lower switch, and the upper switch is electrically connected to the input positive terminal.

[0013] Preferably, it further includes a first control signal and a second control signal, and the first control signal and the second control signal are complementary; the upper switch and the first synchronous rectifier switch are controlled by the first control signal to turn on and off simultaneously, and the lower switch and the second synchronous rectifier switch are controlled by the second control signal to turn on and off simultaneously.

[0014] Preferably, the first end of the high-voltage winding is electrically connected to the switch bridge arm; the second ends of the first low-voltage winding and the second low-voltage winding are electrically connected to the positive output terminal, and the first ends of the first low-voltage winding and the second low-voltage winding are electrically connected to the corresponding synchronous rectifier switches; the first end of the high-voltage winding, the second end of the first low-voltage winding, and the first end of the second low-voltage winding are homologous ends.

[0015] Another object of the present invention is to provide a power device, including a first synchronous rectifier switch combination, a second synchronous rectifier switch combination, and the half-turn winding transformer as described in claim 1, wherein the first synchronous rectifier switch combination is disposed adjacent to the second side surface, and the second synchronous rectifier switch combination is disposed adjacent to the fourth side surface.

[0016] Preferably, it further includes a positive input terminal, a negative input terminal, a positive output terminal, an input capacitor, an output capacitor, and a high-voltage side circuit; the input capacitor is connected in parallel between the positive input terminal and the negative input terminal; the high-voltage side circuit is connected in parallel between the positive input terminal and the positive output terminal, each of the low-voltage winding combinations includes a first low-voltage winding and a second low-voltage winding, and each of the synchronous rectifier switch combinations includes a first synchronous rectifier switch and a second synchronous rectifier switch; the first low-voltage winding and the first synchronous rectifier switch are connected in series across the positive output terminal and the negative input terminal, and the second low-voltage winding and the second synchronous rectifier switch are connected in series across the positive output terminal and the negative input terminal; the output capacitor is connected in parallel between the positive output terminal and the negative input terminal, and is disposed adjacent to the second side surface and the fourth side surface of the magnetic core.

[0017] The beneficial effects of the present invention are as follows:

[0018] (1) The half-turn winding transformer of the present invention can achieve the step-down ratio between various input voltages and output voltages of the intermediate bus conversion device, and meet the applications with different output voltage requirements.

[0019] (2) Through the winding method and device layout of the transformer, the present invention reduces the loss of the transformer and reduces the volume of the transformer. Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0021] Figure 1 Schematic diagram of a half-bridge LLC circuit topology for the prior art;

[0022] Figure 2A Schematic diagram of circuit topology 1a of the present invention;

[0023] Figure 2B Control timing diagram for each power switch of circuit topology 1a;

[0024] Figure 3A Schematic diagram of circuit topology 1b of the present invention;

[0025] Figure 3B Winding method of the low-voltage winding of the transformer in circuit topology 1b;

[0026] Figure 3C Device layout of the low-voltage circuit in circuit topology 1b;

[0027] Figure 3D Winding method of the half-turn high-voltage winding of the transformer in circuit topology 1b;

[0028] Figure 3E and Figure 3F Winding method of the 1.5-turn high-voltage winding of the transformer in circuit topology 1b;

[0029] Wherein:

[0030] 1a / 1b circuit topology; 2 high-voltage side circuit; 3 low-voltage side circuit; 11 / 13 side columns; 12 middle column; 21 first channel; 22 second channel; 31 first side; 32 second side; 33 third side; 34 fourth side; A / B / C / D / Ca / Cb / Da / Db connection points; Cin / input capacitor; Cr1 / Cr2 half-bridge capacitors; Co output capacitor; I1 / I2 currents; PWM1 first pulse width control signal; PWM2 second pulse width control signal;

[0031] SR1 / SR2 / SR1a / SR1b / SR2a / SR2b synchronous rectifier switches; Ts switching period;

[0032] High-voltage winding of TW11 / TW11a / TW11b; low-voltage winding of TW21 / TW22 / TW21a / TW21b / TW22a / TW22b; half-bridge switches of Q1 / Q2; positive input terminal of Vin+; negative input terminal of Vin-; positive output terminal of Vo+. Detailed implementation manner

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] As Figure 1 Shown in the schematic diagram of the traditional half-bridge LLC circuit, which includes a high-voltage side circuit 2, a low-voltage side circuit 3, and an input capacitor Cin; wherein, the input capacitor Cin is connected across the positive input terminal Vin+ and the negative input terminal Vin-; the power switch on the high-voltage side can achieve zero-voltage turn-on, and the synchronous rectification switch on the low-voltage side can achieve zero-current turn-on and turn-off. This half-bridge LLC circuit has the advantages of fewer primary power switch devices, simple circuit, and small size. When the half-bridge LLC circuit is applied to the occasion of large output current, in order to reduce the winding loss of the transformer, the number of turns of the low-voltage side windings TW21 and TW22 of the transformer is usually selected as 1 or 0.5. However, when the number of turns of the low-voltage side windings TW21 and TW22 of the transformer is selected as 1 or 0.5, the step-down ratio of the input voltage Vin to the output voltage Vo of this circuit topology is always a multiple of 2 or 4, and it is difficult to achieve an odd step-down ratio K of the input voltage to the output voltage, resulting in a limited adaptation range of the output voltage of this circuit topology, and thus limiting the application scenarios of this circuit topology. Specifically, when the turn ratio of TW11, TW21, and TW22 is N:1:1, Vin = 2N * Vo; when the turn ratio of TW11, TW21, and TW22 is N:0.5:0.5, Vin = 4N * Vo; here N is a natural number.

[0035] The embodiments of the present invention can achieve an odd step-down ratio K of the input voltage and the output voltage, making the adaptation range of the output voltage Vo wider and broadening the application scenarios of the ratio converter.

[0036] Figure 2AThe figure shows a schematic diagram of the circuit topology 1a disclosed by the present invention. The circuit topology 1a includes a high-voltage side circuit 2, a low-voltage side circuit 3, an input positive terminal Vin+, an input negative terminal Vin-, and an output positive terminal Vo+. The high-voltage side circuit 2 includes a switching bridge arm, a capacitor bridge arm, and a high-voltage winding TW11; the switching bridge arm includes half-bridge switches Q1 and Q2, and the source electrode of the half-bridge switch Q1 is short-circuited with the drain electrode of Q2 to form a connection point A; the capacitor bridge arm includes half-bridge capacitors Cr1 and Cr2, and Cr1 and Cr2 are connected in series to form a connection point B. The input capacitor Cin is still connected across the input positive terminal Vin+ and the input negative terminal Vin-; the switching bridge arm and the capacitor bridge arm are connected in parallel and connected across the input positive terminal Vin+ and the output positive terminal Vo+. The low-voltage side circuit 3 is a center-tapped rectifier circuit, including synchronous rectifier switches SR1 and SR2, low-voltage windings TW21 and TW22, and an output capacitor Co. The second ends of the low-voltage windings TW21 and TW22 are short-circuited to the output positive terminal Vo+; the first ends of the low-voltage windings TW21 and TW22 are respectively electrically connected to the drain electrodes of the corresponding synchronous rectifier switches SR1 and SR2; the source electrodes of the synchronous rectifier switches SR1 and SR2 are short-circuited, and the output capacitor Co is connected across the output positive terminal Vo+ and the source electrodes of the synchronous rectifier switches SR1 and SR2. The high-voltage winding TW11 is magnetically coupled with the low-voltage windings TW21 and TW22 to form a transformer, that is, the high-voltage winding TW11 of the transformer and the low-voltage windings TW21 and TW22 of the transformer are wound on the same magnetic core, and further wound on the same magnetic column of the same magnetic core; and the first end of the high-voltage winding TW11 (i.e., the end electrically connected to the connection point A), the second end of the low-voltage winding TW21 (i.e., the end electrically connected to the output positive terminal Vo+), and the first end of the low-voltage winding TW22 (i.e., the end electrically connected to the drain electrode of the synchronous rectifier switch SR2) are mutually corresponding ends, marked as dot ends.

[0037] In the circuit topology 1a, the leakage inductance of the transformer resonates with the half-bridge capacitors Cr1 and Cr2; because the magnetizing inductance of the transformer is small, a large magnetizing current can be generated to achieve zero-voltage turn-on of the half-bridge switch Q1 or Q2.

[0038] As Figure 2B shown, the half-bridge switch Q1 and the synchronous rectifier switch SR1 are controlled by the first pulse width control signal PWM1; the half-bridge switch Q2 and the synchronous rectifier switch SR2 are controlled by the second pulse width control signal PWM2. In a switching period Ts (i.e., the interval 0 to t4), the intervals t1 to t2 and the interval t3 to t4 are dead times; in the interval 0 to t1, the half-bridge switch Q2 and the synchronous rectifier switch SR2 are approximately turned on and off simultaneously; in the interval t2 to t3, the half-bridge switch Q1 and the synchronous rectifier switch SR1 are approximately turned on and off simultaneously. If the dead time is ignored, the first pulse width control signal PWM1 and the second pulse width control signal PWM2 are complementary, and the duty cycles are both close to 0.5.

[0039] When the number of turns of the low-voltage windings TW21 and TW22 is 1 turn each, the turn ratio of the high-voltage winding TW11 to the low-voltage windings TW21 and TW22 is N:1:1, where N is a natural number. The input voltage Vin and the output voltage Vo satisfy Equation (1):

[0040] Vin = (2N + 1) * Vo (1)

[0041] The step-down ratio K of the input voltage Vin to the output voltage Vo is K = 2N + 1. Taking N as 1, 2, and 3 respectively as examples, the corresponding step-down ratios K are 3, 5, and 7 respectively. Therefore, through the circuit topology 1a and the control method disclosed in the present invention, the step-down ratio K of the input voltage and the output voltage can be made an odd number, making the applicable range of the output voltage Vo wider and broadening the application scenarios of the proportional converter.

[0042] In order to further reduce the conduction loss of the transformer, the number of turns of the low-voltage side winding of the transformer can be designed to be 0.5 turn, and the turn ratio of the high-voltage winding TW11 to the low-voltage windings TW21 and TW22 is N:0.5:0.5; at this time, the input voltage Vin and the output voltage Vo satisfy Equation (2):

[0043] Vin = (4N + 1) * Vo (2)

[0044] The step-down ratio K of the input voltage Vin to the output voltage Vo is K = 4N + 1. Taking N as 1, 2, and 3 respectively as examples, the number of turns of the high-voltage winding TW11 is 1, 2, and 3 respectively, and the corresponding step-down ratios K are 5, 9, and 13 respectively. In this application, although a high step-down ratio is achieved, since the minimum step-down ratio is 5, the applicable range of the output voltage Vo is limited. On this basis, the high-voltage winding TW11 can also adopt a half-turn design, that is, the turn ratio of the high-voltage winding TW11 to the low-voltage windings TW21 and TW22 is (N - 0.5):0.5:0.5, where N is a natural number. At this time, the input voltage Vin and the output voltage Vo satisfy Equation (3):

[0045] Vin = (4N - 1) * Vo (3)

[0046] The step-down ratio K of the input voltage Vin to the output voltage Vo is K = 4N - 1. Taking N as 1, 2, and 3 respectively as examples, the number of turns of the high-voltage winding TW11 is 0.5, 1.5, and 2.5 respectively, and the corresponding step-down ratios K are 3, 7, and 11 respectively. In this application, there are more applicable choices for the step-down ratio K of the input voltage Vin to the output voltage Vo.

[0047] The present invention also discloses a structure of a transformer and a winding winding method, which can achieve a half-turn design of the high-voltage winding and a half-turn design of the low-voltage winding. The equivalent circuit schematic diagram is as Figure 3AAs shown, the difference between circuit topology 1b and circuit topology 1a is that the high-voltage winding includes TW11a and TW11b, and the two are connected in parallel; the low-voltage winding includes TW21a, TW21b, TW22a, and TW22b, and the second end of each low-voltage winding is electrically connected to the output positive terminal Vo+. The first end of each low-voltage winding is respectively connected to the drain of a synchronous rectifier switch, corresponding to the drains of SR1a, SR1b, SR2a, and SR2b. The first end of the low-voltage winding TW21a and the drain of the synchronous rectifier switch SR1a are electrically connected to the connection point Ca; the first end of the low-voltage winding TW21b and the drain of the synchronous rectifier switch SR1b are electrically connected to the connection point Cb; the first end of the low-voltage winding TW22a and the drain of the synchronous rectifier switch SR2a are electrically connected to the connection point Da; the first end of the low-voltage winding TW22b and the drain of the synchronous rectifier switch SR2b are electrically connected to the connection point Db. That is, the low-voltage side circuit 3 includes two center-tapped rectifier circuits connected in parallel. The high-voltage windings TW11a and TW11b and the low-voltage windings TW21a, TW21b, TW22a, and TW22b are magnetically coupled to form a transformer, that is, the high-voltage windings TW11a and TW11b of the transformer and the low-voltage windings TW21a, TW21b, TW22a, and TW22b of the transformer are wound on the same magnetic core. Further, they are wound on the same magnetic column of the same magnetic core; and the first ends of the high-voltage windings TW11a and TW11b (i.e., the ends electrically connected to the connection point A), the second ends of the low-voltage windings TW21a and TW21b (i.e., the ends electrically connected to the output positive terminal Vo+), and the first ends of the low-voltage windings TW22a and TW22b (i.e., the ends respectively electrically connected to the synchronous rectifier switch SR2a or SR2b) are homologous ends, marked as dot ends. As Figure 3B and Figure 3CThe shown transformer core structure and the winding method of the low-voltage winding. The core adopted in the present invention includes a first side surface 31, a second side surface 32, a third side surface 33, and a fourth side surface 34, where the first side surface 31 and the third side surface 33 are opposite, and the second side surface 32 and the fourth side surface 34 are opposite. The core further includes two magnetic substrates (not shown in the figure), side columns 11 and 13, and a middle column 12. The side columns 11 and 13 and the middle column 12 are arranged between the two magnetic substrates, and the side column 11, the middle column 12, and the side column 13 are arranged in sequence in the same direction. The channel between the side column 11 and the middle column 12 is the first channel 21, and the channel between the side column 13 and the middle column 12 is the second channel 22. Both the first channel 21 and the second channel 22 penetrate through the second side surface 32 and the fourth side surface 34. The high-voltage windings TW11a and TW11b and the low-voltage windings TW21a and TW21b and TW22a and TW22b can be arranged in the circuit board PCB, and the high-voltage winding and the two low-voltage windings are respectively arranged on different wiring layers of the circuit board PCB. The core is buckled to the circuit board and magnetically coupled with the windings to form a transformer, but the winding method disclosed in the present invention is not limited to this implementation. The circuit topology 1b can also adopt Figure 2B The shown control timing, where the half-bridge switch Q1, the synchronous rectifier switches SR1a and SR1b are controlled by the first pulse width control signal PWM1, and the half-bridge switch Q2, the synchronous rectifier switches SR2a and SR2b are controlled by the second pulse width control signal PWM2.

[0048] Figure 3B For the winding method of the low-voltage winding, the low-voltage winding TW21a passes through the first channel 21. The first end (i.e., the connection point Ca) of the low-voltage winding TW21a is arranged adjacent to the second side surface 32, and the second end (i.e., the output positive terminal Vo+) of the low-voltage winding TW21a is arranged adjacent to the fourth side surface 34; the low-voltage winding TW22a passes through the second channel 22. The first end (i.e., the connection point Da) of the low-voltage winding TW22a is arranged adjacent to the second side surface 32, and the second end (i.e., the output positive terminal Vo+) of the low-voltage winding TW22a is arranged adjacent to the fourth side surface 34; the low-voltage winding TW21b passes through the second channel 22. The first end (i.e., the connection point Cb) of the low-voltage winding TW21b is arranged adjacent to the fourth side surface 34, and the second end (i.e., the output positive terminal Vo+) of the low-voltage winding TW21b is arranged adjacent to the second side surface 32; the low-voltage winding TW22b passes through the first channel 21. The first end (i.e., the connection point Db) of the low-voltage winding TW22b is arranged adjacent to the fourth side surface 34, and the second end (i.e., the output positive terminal Vo+) of the low-voltage winding TW22b is arranged adjacent to the second side surface 32.

[0049] Figure 3CShown is the device layout of the low-voltage side circuit 3. The synchronous rectifier switches SR1a and SR2a are arranged adjacent to the second side 32. The synchronous rectifier switch SR1a is connected in parallel across the connection point Ca and the ground terminal (i.e., the input negative terminal Vin-). The synchronous rectifier switch SR2a is connected in parallel across the connection point Da and the ground terminal (i.e., the input negative terminal Vin-). The synchronous rectifier switches SR1b and SR2b are arranged adjacent to the fourth side 34. The synchronous rectifier switch SR1b is connected in parallel across the connection point Cb and the ground terminal (i.e., the input negative terminal Vin-). The synchronous rectifier switch SR2b is connected in parallel across the connection point Db and the ground terminal. The output capacitor Co is arranged adjacent to the second side 32 and the fourth side 34 respectively, and is connected in parallel across the output positive terminal Vo+ and the ground terminal.

[0050] As Figure 3C shown, the structure and winding method of 0.5 turns of the low-voltage winding and the corresponding layout of the low-voltage circuit make the path of the low-voltage winding short and the impedance low, reducing the losses generated on the low-voltage winding. By arranging the synchronous rectifier switches on the opposite sides of the magnetic core respectively, the space on the opposite sides of the magnetic core can be utilized more fully. Not only the number of synchronous rectifier switches doubles, but also the conduction loss of the power module is further reduced. Furthermore, the low-voltage windings TW21a and TW22a are arranged in different channels respectively. Comparing the current flowing through the low-voltage winding TW21a and the current flowing through the low-voltage winding TW22a, the magnitudes and directions of their DC currents are the same, the frequencies and magnitudes of their AC currents are basically the same, and the phases are out of phase by 180 degrees. The low-voltage windings TW21b and TW22b are arranged in different channels respectively. Comparing the current flowing through the low-voltage winding TW21b and the current flowing through the low-voltage winding TW22b, the magnitudes and directions of their DC currents are the same, the frequencies and magnitudes of their AC currents are basically the same, and the phases are out of phase by 180 degrees. The low-voltage windings TW21a and TW22b are arranged in the first channel 21. Comparing the current flowing through the low-voltage winding TW21a and the current flowing through the low-voltage winding TW22b, the directions of their DC currents are opposite and the magnitudes are approximately the same. Further, the superposition of these two currents can form a complete sine wave. The low-voltage windings TW21b and TW22a are arranged in the second channel 22. Comparing the current flowing through the low-voltage winding TW21b and the current flowing through the low-voltage winding TW22a, the directions of their DC currents are opposite and the magnitudes are approximately the same. Further, the superposition of these two currents can form a complete sine wave.

[0051] Figure 3DThe winding methods of the high-voltage windings TW11a and TW11b with 0.5 turns are shown. The first ends of the high-voltage windings TW11a and TW11b are both electrically connected to the midpoint of the switch bridge arm (i.e., connection point A), and the first ends are both arranged adjacent to the second side surface 32; starting from the first end, the high-voltage winding TW11a passes through the second channel 22 and winds along the fourth side surface 34 and the first side surface 31, and the second end is electrically connected to the midpoint of the capacitor bridge arm (i.e., connection point B); the midpoint of the capacitor bridge arm is arranged adjacent to the first side surface 31 and the second side surface 32; after passing through the first side surface 31 of the magnetic core, the first end of the high-voltage winding TW11b passes through the first channel 21 from the fourth side surface 34 of the magnetic core, and the second end is electrically connected to the midpoint of the capacitor bridge arm (i.e., connection point B). Here, the setting positions of the first end and the second end of the high-voltage winding are not limited to this, as long as they are adjacent to the same side surface of the magnetic core, the requirements of this embodiment can be met.

[0052] In the second channel 22, the fundamental wave current of the high-voltage winding TW11a has the same frequency and amplitude but opposite direction compared with the fundamental wave current after being superimposed with the currents of the low-voltage windings TW21b and TW22a; so that the fundamental wave current in the second channel 22 is close to being canceled; and because the high-voltage winding TW11a, the low-voltage windings TW21b and TW22a overlap in position in the circuit board and their arrangements in different wiring layers satisfy the interleaving relationship, the AC resistance of the windings passing through the second channel 22 is small and the winding loss is low. In the first channel 21, the direction of the fundamental wave current of the high-voltage winding TW11b has the same frequency and amplitude but opposite direction compared with the fundamental wave current after being superimposed with the currents of the low-voltage windings TW21a and TW22b; so that the fundamental wave current in the first channel 21 is close to being canceled; and because the high-voltage winding TW11b, the low-voltage windings TW21a and TW22b overlap in position in the circuit board and their arrangements in different wiring layers satisfy the interleaving relationship, the AC resistance of the windings passing through the first channel 21 is small and the winding loss is low. At the same time, outside the magnetic core, that is, at the position adjacent to the first side surface 31, the current directions of the high-voltage windings TW11a and TW11b are opposite and the current magnitudes are approximately equal. Also, because the two high-voltage windings overlap in position in the circuit board and their arrangements in different wiring layers satisfy the interleaving relationship, the AC resistance of the windings in the outer part of the magnetic core is small and the winding loss is low; similarly, at the position adjacent to the second side surface 32 or at the position adjacent to the fourth side surface 34, the current directions of the high-voltage windings TW11a and TW11b are opposite and the current magnitudes are approximately equal, and the two high-voltage windings overlap in position in the circuit board and their arrangements in different wiring layers satisfy the interleaving relationship. In the present invention, the high-voltage winding is divided into two branches of the high-voltage windings TW11a and TW11b, which not only realizes the winding of 0.5 turns of the high-voltage winding, makes the turn ratio relationship between the high-voltage winding and the low-voltage winding of the transformer meet the requirements of the output voltage, but also reduces the AC resistance of the winding.

[0053] Figure 3DThe winding method of the half-turn high-voltage winding shown can also be extended to 1.5 turns, 2.5 turns, or even N + 0.5 turns. As Figure 3E and Figure 3F shown, Figure 3E shows the winding method of the high-voltage winding TW11a with 1.5 turns, Figure 3F shows the winding method of the high-voltage winding TW11b with 1.5 turns.

[0054] For the high-voltage winding TW11a from the first end to the second end, first pass through the second channel 22 from the second side 32, then wind around the middle column 12 counterclockwise for one turn, then pass out from the fourth side 34, and be electrically connected to the midpoint of the capacitor bridge arm (i.e., connection point B) along the fourth side 34 and the first side 31; for the high-voltage winding TW11b from the first end to the second end, first pass through the first side 31, then pass through the first channel 21 from the fourth side 34, then wind around the middle column 12 counterclockwise for one turn, pass through the second side 32, and the other end is electrically connected to the midpoint of the capacitor bridge arm (i.e., connection point B). With this embodiment, multiple step-down ratios of the input voltage to the output voltage can be achieved, enabling the circuit topology 1b to meet more output voltage requirements.

[0055] In addition, realizing the parallel connection of the high-voltage winding and the parallel connection of the low-voltage winding within the same magnetic core not only expands the load-carrying capacity of the power conversion device adopting this circuit topology, but also reduces the volume of the magnetic core, achieving a high power density of the power conversion device.

[0056] The switching tubes disclosed in the present invention can be SiMOSFET, SiCMOSFET, GaNMOSFET, or IGBTMOSFET, etc., all of which can achieve the switching functions disclosed in the present invention.

[0057] The power conversion device described in the above embodiments can be an independent module or a part of an electronic device, as long as it can meet the technical features and benefits disclosed in the present invention.

[0058] For the "equal" or "same" or "equal to" disclosed in the present invention, the engineering parameter distribution must be considered, and the error distribution is within ±30%; the definition of "parallel" for two line segments or two straight lines is that the included angle between the two line segments or two straight lines is less than or equal to 45 degrees; the definition of "perpendicular" for two line segments or two straight lines is that the included angle between the two line segments or two straight lines is in the range of [60, 120] degrees; the definition of "phase misalignment" of the phase also needs to consider the engineering parameter distribution, and the error distribution of the misalignment degree is within ±30%.

[0059] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0060] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A half-turn winding transformer, characterized in that, It includes a magnetic core and windings. The windings include a first high-voltage winding, a second high-voltage winding, a first low-voltage winding combination, and a second low-voltage winding combination. The magnetic core includes two magnetic substrates, two side columns, and a middle column. The two side columns and the middle column are arranged between the two magnetic substrates. The two side columns and the middle column are arranged in the same direction, and the middle column is arranged between the two side columns. The two channels between the two side columns and the middle column are the first channel and the second channel respectively. The magnetic core includes a first side, a second side, a third side, and a fourth side. The first side and the third side are opposite to each other, and the second side and the fourth side are opposite to each other. Both the first channel and the second channel penetrate through the second side and the fourth side. Each winding includes a first end and a second end. The first end and the second end of each high-voltage winding are arranged adjacent to the same side of the magnetic core. The second end of the first low-voltage winding combination and the first end of the second low-voltage winding combination are both arranged adjacent to the fourth side of the magnetic core. The first end of the first low-voltage winding combination and the second end of the second low-voltage winding combination are both arranged adjacent to the second side of the magnetic core. Each low-voltage winding combination includes two low-voltage windings. The two low-voltage windings in each low-voltage winding combination respectively pass through the first channel and the second channel. The first high-voltage winding passes through the second side, the first channel, and the fourth side in sequence from the first end to the second end. The second high-voltage winding passes through the fourth side, the second channel, and the second side in sequence from the first end to the second end.

2. The half-turn winding transformer according to claim 1, characterized in that, The voltage waveforms at both ends of the two low-voltage windings passing through the same channel are out of phase by 180 degrees. The voltage waveforms at both ends of the two low-voltage windings within the same low-voltage winding combination are out of phase by 180 degrees.

3. The half-turn winding transformer according to claim 1, characterized in that, The first high-voltage winding passes through the second side first from the first end to the second end, then passes through the first channel, winds around the middle column for at least one turn, and finally passes through the fourth side. The second high-voltage winding passes through the fourth side first from the first end to the second end, then passes through the second channel, winds around the middle column for at least one turn, and finally passes through the second side.

4. The half-turn winding transformer according to claim 1, wherein In the first channel, the fundamental waves flowing through the high-voltage winding and the fundamental waves flowing through the two low-voltage windings are positive and negative to each other and cancel each other out. In the second channel, the fundamental waves flowing through the high-voltage winding and the fundamental waves flowing through the two low-voltage windings are positive and negative to each other and cancel each other out.

5. A circuit topology, characterized in that, It includes an input positive terminal, an input negative terminal, an output positive terminal, an input capacitor, an output capacitor, a high-voltage side circuit, and a low-voltage side circuit. The input capacitor is connected across the input positive terminal and the input negative terminal. The high-voltage side circuit is connected across the input positive terminal and the output positive terminal. The low-voltage side circuit is connected across the output positive terminal and the input negative terminal. The low-voltage side circuit is a center-tapped rectifier circuit, which includes a first low-voltage winding combination and a first synchronous rectifier switch combination. The first low-voltage winding combination includes a first low-voltage winding and a second low-voltage winding. The first synchronous rectifier switch combination includes a first synchronous rectifier switch and a second synchronous rectifier switch. The first low-voltage winding and the first synchronous rectifier switch are connected in series across the output positive terminal and the input negative terminal. The second low-voltage winding and the second synchronous rectifier switch are connected in series across the output positive terminal and the input negative terminal. The output capacitor is connected across the output positive terminal and the input negative terminal.

6. The circuit topology according to claim 5, characterized in that, The high-voltage side circuit includes a switch bridge arm, a capacitor bridge arm, and a high-voltage side winding. The high-voltage side winding is connected across the midpoint of the switch bridge arm and the midpoint of the capacitor bridge arm. The switch bridge arm includes an upper switch and a lower switch, and the upper switch is electrically connected to the input positive terminal.

7. The circuit topology according to claim 6, characterized in that, It further includes a first control signal and a second control signal, and the first control signal and the second control signal are complementary. The upper switch and the first synchronous rectifier switch are controlled by the first control signal to turn on and off simultaneously. The lower switch and the second synchronous rectifier switch are controlled by the second control signal to turn on and off simultaneously.

8. The circuit topology according to claim 6, wherein The first end of the high-voltage winding is electrically connected to the switch bridge arm. The second ends of the first low-voltage winding and the second low-voltage winding are electrically connected to the output positive terminal. The first ends of the first low-voltage winding and the second low-voltage winding are electrically connected to the corresponding synchronous rectifier switches. The first end of the high-voltage winding, the second end of the first low-voltage winding, and the first end of the second low-voltage winding are homologous ends.

9. A power device, characterized in that, It includes a first synchronous rectifier switch combination, a second synchronous rectifier switch combination, and the half-turn winding transformer as claimed in claim 1. The first synchronous rectifier switch combination is disposed adjacent to the second side surface, and the second synchronous rectifier switch combination is disposed adjacent to the fourth side surface.

10. The power device according to claim 9, characterized in that, It further includes an input positive terminal, an input negative terminal, an output positive terminal, an input capacitor, an output capacitor, and a high-voltage side circuit. The input capacitor is connected across the input positive terminal and the input negative terminal. The high-voltage side circuit is connected across the input positive terminal and the output positive terminal. Each of the low-voltage winding combinations includes a first low-voltage winding and a second low-voltage winding. Each of the synchronous rectifier switch combinations includes a first synchronous rectifier switch and a second synchronous rectifier switch. The first low-voltage winding and the first synchronous rectifier switch are connected in series across the output positive terminal and the input negative terminal. The second low-voltage winding and the second synchronous rectifier switch are connected in series across the output positive terminal and the input negative terminal. The output capacitor is connected across the output positive terminal and the input negative terminal and is disposed adjacent to the second side surface and the fourth side surface of the magnetic core.

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