Flyback conversion circuit

Abstract

The invention discloses a flyback conversion circuit, which comprises N flyback conversion sub-circuits and an input power supply circuit, and is characterized in that the input end of each flyback conversion sub-circuit is connected with the output end of the input power supply circuit; the flyback conversion sub-circuit comprises an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit and M power conversion circuits; the first input end of the active absorption circuit is connected with the first end of the clamping capacitor, the second input end of the active absorption circuit is connected with the first end of the input filter capacitor or the second end of the input filter capacitor, and the first output end of the active absorption circuit is connected with the first input end of the output filter circuit. The second output end of the active absorption circuit is connected with the second input end of the output filter circuit. By adopting the design of multi-path staggered conduction control and unified energy absorption, the power conversion efficiency and power density of the circuit can be effectively improved, the voltage stress of the device is reduced, and the electromagnetic compatibility is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power electronic conversion, and in particular to a flyback conversion circuit. Background Art

[0002] As a typical isolated DC-DC converter topology, the flyback converter has been widely used in small and medium-power power systems due to its simple structure, flexible control, small component count, high system reliability, and low cost. It is particularly suitable for applications such as mobile phone chargers, small appliance adapters, and auxiliary power supplies in industrial equipment. This type of converter achieves electrical isolation between the input and output by asynchronously conducting the primary and secondary windings of the transformer. It also utilizes the transformer's magnetic core for temporary energy storage, enabling isolated energy transmission without the need for an additional air gap.

[0003] However, flyback converters typically operate in discontinuous conduction mode (DCB), resulting in both input and output currents being pulsed and discontinuous, which can easily cause significant electromagnetic interference (EBI) and output voltage ripple. Therefore, to meet the power supply system's voltage stability and electromagnetic compatibility requirements, large input and output filter capacitors are typically required for filtering and suppression.

[0004] To further expand the application capabilities of flyback converters in medium- and high-power scenarios and alleviate interference issues caused by input and output current ripple, existing technologies have proposed solutions using interleaved parallel topologies. By controlling the timing of multiple flyback converter units in staggered phases, it is possible to increase power output while effectively improving current continuity and reducing system electromagnetic interference. However, as the number of parallel paths increases, the spike voltages caused by transformer leakage inductance and the resulting energy losses become increasingly significant, becoming a major bottleneck limiting overall conversion efficiency improvements. To suppress this spike energy and recover the useful work it contains, some existing technologies have introduced active snubber circuits for energy absorption and reuse. However, if each flyback converter unit in the interleaved parallel structure is independently configured with a corresponding active snubber circuit, the circuit's structural complexity, component count, and control logic burden will be significantly increased, leading to a significant increase in system implementation difficulty and overall cost.

[0005] This section is intended to provide a background or context to the embodiments of the present application that are recited in the claims. No admission is made that the description herein is prior art by virtue of its inclusion in this section. Summary of the Invention

[0006] An embodiment of the present application provides a flyback conversion circuit for achieving efficient energy conversion and active recovery of leakage inductance energy in high power density scenarios, thereby improving the energy utilization efficiency and circuit stability of the circuit.

[0007] The flyback conversion circuit includes: N flyback conversion sub-circuits and an input power supply circuit, wherein the input end of each flyback conversion sub-circuit is connected to the output end of the input power supply circuit;

[0008] The i-th flyback conversion sub-circuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and M power conversion circuits, wherein the output filter circuit includes at least one output filter capacitor; wherein N is a positive integer greater than or equal to 1, M is a positive integer greater than or equal to 1, 1≤i≤N, and i is a positive integer;

[0009] The j-th power conversion circuit among the M power conversion circuits of the i-th flyback conversion sub-circuit includes: a first switch tube, a main transformer, a clamping diode and a first rectifier diode, wherein 1≤j≤M and j is a positive integer;

[0010] The first end of the i-th input filter capacitor is respectively connected to the first end of the primary winding of all the main transformers of the M power conversion circuits in the i-th flyback conversion sub-circuit, and the second end of the i-th input filter capacitor is respectively connected to the first end of all the first switching tubes of the M power conversion circuits in the i-th flyback conversion sub-circuit;

[0011] The first end of the i-th clamping capacitor is respectively connected to the cathodes of all clamping diodes of the M power conversion circuits in the i-th flyback conversion sub-circuit, and the second end of the i-th clamping capacitor is respectively connected to the first ends of the primary windings of all main transformers of the M power conversion circuits in the i-th flyback conversion sub-circuit or respectively connected to the first ends of all first switching transistors of the M power conversion circuits in the i-th flyback conversion sub-circuit;

[0012] The second end of the jth first switching tube is connected between the anode of the jth clamping diode and the second end of the primary winding of the jth main transformer;

[0013] The first end of the secondary winding of the jth main transformer is connected to the anode of the jth first rectifier diode; the cathode of the first rectifier diode in the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the first end of at least one output filter capacitor in the i-th output filter circuit; the second end of the secondary winding of the main transformer of the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the second end of at least one output filter capacitor in the i-th output filter circuit;

[0014] The first input end of the i-th active absorption circuit is connected to the first end of the i-th clamping capacitor, the second input end of the i-th active absorption circuit is connected to the first end of the i-th input filter capacitor or the second end of the i-th input filter capacitor, the first output end of the i-th active absorption circuit is connected to the first input end of the i-th output filter circuit, and the second output end of the i-th active absorption circuit is connected to the second input end of the i-th output filter circuit.

[0015] The embodiment of the present application also provides a flyback conversion circuit for achieving efficient energy conversion and active recovery of leakage inductance energy in high power density scenarios, thereby improving the energy utilization efficiency and circuit stability of the circuit.

[0016] A flyback conversion circuit comprises: A flyback conversion sub-circuits and an input power supply circuit, wherein the input end of each flyback conversion sub-circuit is connected to the output end of the input power supply circuit;

[0017] The ath flyback conversion subcircuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and B power conversion circuits, wherein the output filter circuit includes at least one output filter capacitor; wherein A is a positive integer greater than or equal to 1 and B is a positive integer greater than or equal to 1, or A is a positive integer greater than or equal to 2 and B is a positive integer greater than or equal to 1, 1≤a≤A, and a is a positive integer;

[0018] The bth power conversion circuit among the B power conversion circuits of the ath flyback conversion sub-circuit comprises: a first switch tube, a main transformer, a clamping diode and a first rectifier diode, wherein 2≤b≤B and b is a positive integer;

[0019] The first end of the ath input filter capacitor is respectively connected to the first end of the primary winding of all the main transformers of the B power conversion circuits in the ath flyback conversion sub-circuit, and the second end of the ath input filter capacitor is respectively connected to the first end of all the first switching tubes of the B power conversion circuits in the ath flyback conversion sub-circuit;

[0020] The first end of the ath clamping capacitor is respectively connected to the cathodes of all clamping diodes of the B power conversion circuits in the ath flyback conversion sub-circuit, and the second end of the ath clamping capacitor is respectively connected to the first ends of the primary windings of all main transformers of the B power conversion circuits in the ath flyback conversion sub-circuit or respectively connected to the first ends of all first switching transistors of the B power conversion circuits in the ath flyback conversion sub-circuit;

[0021] The second end of the bth first switching tube is connected between the bth clamping diode and the second end of the bth primary winding of the main transformer;

[0022] The first end of the secondary winding of the bth main transformer is connected to the positive electrode of the bth first rectifier diode; the cathode of the first rectifier diode in the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the first end of the at least one output filter capacitor in the ath output filter circuit, and the second end of the secondary winding of the main transformer in the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the second end of the at least one output filter capacitor in the ath output filter circuit;

[0023] The first end of the ath active absorption circuit is connected between the ath clamping capacitor and all the clamping diodes of the B power conversion circuits in the ath flyback conversion sub-circuit, the second end of the ath active absorption circuit is connected between the ath input filter capacitor and the first end of the primary winding of all the main transformers of the B power conversion circuits in the ath flyback conversion sub-circuit, and the third end of the ath active absorption circuit is connected between the ath input filter capacitor and the first end of all the first switching tubes of the B power conversion circuits in the ath flyback conversion sub-circuit.

[0024] The flyback converter circuit provided in the embodiments of the present application, in accordance with the above-described embodiments, effectively achieves temporary storage and active recovery of leakage inductance energy from the primary winding of the main transformer by introducing a set of rationally structured clamping branches and active absorption paths into the flyback converter circuit, significantly improving the circuit's energy conversion efficiency and the operating stability of the switching device. The clamping branch constructed by the clamping capacitor and clamping diode absorbs high-frequency spike voltages caused by leakage inductance on the primary winding side when the first switching transistor is turned off, thereby avoiding stress damage to the device caused by the spike impact and enhancing the circuit's reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0026] Figure 1 A flyback converter circuit with an active absorption circuit in one embodiment of the present application;

[0027] Figure 2 A flyback converter circuit with an active absorption circuit in another embodiment of the present application;

[0028] Figure 3 A flyback converter circuit with an active absorption circuit in another embodiment of the present application;

[0029] Figure 4 A flyback converter circuit with an active absorption circuit in another embodiment of the present application;

[0030] Figure 5 A DC flyback converter circuit sharing an active absorption circuit in an embodiment of the present application;

[0031] Figure 6 An AC flyback converter circuit sharing an active absorption circuit in an embodiment of the present application;

[0032] Figure 7 A flyback converter circuit in one embodiment of the present application;

[0033] Figure 8 A flyback converter circuit in another embodiment of the present application;

[0034] Figure 9 A flyback converter circuit with an active absorption circuit in another embodiment of the present application;

[0035] Figure 10 A flyback converter circuit with an active absorption circuit in another embodiment of the present application;

[0036] Figure 11 A flyback converter circuit with an active absorption circuit in another embodiment of the present application;

[0037] Figure 12 A DC flyback converter circuit sharing an active absorption circuit in another embodiment of the present application;

[0038] Figure 13 This is an AC flyback converter circuit that shares an active absorption circuit in another embodiment of the present application;

[0039] Figure 14 A flyback converter circuit in another embodiment of the present application;

[0040] Figure 15 A flyback converter circuit in another embodiment of the present application;

[0041] Figure 16 This is a schematic diagram of the timing control of the main power switch tube in the flyback conversion circuit. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] In this application, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe this application and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0045] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0046] Furthermore, the terms "installed," "disposed," "provided with," "connected," "connected," and "socketed" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0047] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this 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.

[0048] In order to solve the problems of low energy conversion efficiency, high device voltage stress, insufficient leakage inductance energy recovery, and difficult circuit structure integration in flyback conversion circuits under high-frequency operating conditions in multi-phase high-power density applications, the present application provides a flyback conversion circuit. The flyback conversion circuit is driven by multiple AC power sources and connected to three flyback conversion sub-circuits respectively. Each conversion circuit achieves unified absorption and efficient transmission of the leakage inductance energy of the primary side of the main transformer by sharing a clamping capacitor and combining a centralized active absorption circuit. At the same time, a multi-channel parallel output structure of the secondary winding inductive energy is adopted. In some embodiments, it supports connecting 12 output rectifier branches in parallel, or connecting 6 and 6 output rectifier branches in series, and uniformly rectifying and transmitting them to the output filter capacitor and load resistor, thereby improving the energy feedback efficiency. Compared with traditional discrete clamping and absorption solutions, the above structure supports multi-channel interleaved parallel connection and multi-phase input integrated design, effectively reducing the overall electromagnetic interference and device redundancy of the circuit, and improving the circuit thermal management capability and output voltage stability.

[0049] like Figure 1 and Figure 2 As shown, the flyback conversion circuit includes: N flyback conversion sub-circuits and an input power circuit, and the input end of each flyback conversion sub-circuit is connected to the output end of the input power circuit.

[0050] The i-th flyback conversion sub-circuit includes: input filter capacitor C in , clamping capacitor C1, output filter circuit, active absorption circuit and M power conversion circuits, the output filter circuit includes at least one output filter capacitor C O Wherein, N is a positive integer greater than or equal to 1, M is a positive integer greater than or equal to 1, 1≤i≤N and i is a positive integer.

[0051] The jth power conversion circuit among the M power conversion circuits of the i-th flyback conversion sub-circuit includes: a first switch tube Q1, a main transformer T1, a clamping diode A1 and a first rectifier diode B1, where 1≤j≤M and j is a positive integer.

[0052] The i-th input filter capacitor C in The first end of each of the primary windings of the main transformers T1 of the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the first end of each of the primary windings of the main transformers T1 of the M power conversion circuits in the i-th flyback conversion sub-circuit. The i-th input filter capacitor C in The second end of is respectively connected to the first end of all the first switch tubes Q1 of the M power conversion circuits in the i-th flyback conversion sub-circuit.

[0053] The first end of the i-th clamping capacitor C1 is respectively connected to the cathodes of all the clamping diodes A1 of the M power conversion circuits in the i-th flyback conversion sub-circuit, and the second end of the i-th clamping capacitor C1 is respectively connected to the first ends of the primary windings of all the main transformers T1 of the M power conversion circuits in the i-th flyback conversion sub-circuit or respectively connected to the first ends of all the first switching tubes Q1 of the M power conversion circuits in the i-th flyback conversion sub-circuit.

[0054] The second end of the j-th first switch tube Q1 is connected between the anode of the j-th clamping diode A1 and the second end of the primary winding of the j-th main transformer T1 .

[0055] The first end of the secondary winding of the jth main transformer T1 is connected to the anode of the jth first rectifier diode B1. The cathode of the first rectifier diode B1 in the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the cathode of at least one output filter capacitor C in the i-th output filter circuit. O The first end of the secondary winding of the main transformer T1 of the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the second end of the secondary winding of the main transformer T1 of the M power conversion circuits in the i-th flyback conversion sub-circuit and at least one output filter capacitor C in the i-th output filter circuit O The second end of the

[0056] The first input terminal of the i-th active absorption circuit is connected to the first terminal of the i-th clamping capacitor C1, and the second input terminal of the i-th active absorption circuit is connected to the i-th input filter capacitor C in The first terminal or the i-th input filter capacitor C in The second end is connected, the first output end of the i-th active absorption circuit is connected to the first input end of the i-th output filter circuit, and the second output end of the i-th active absorption circuit is connected to the second input end of the i-th output filter circuit.

[0057] According to the above embodiment, the energy efficiency improvement and modular integration of the flyback conversion circuit in high-power application scenarios are achieved through a three-phase multi-channel staggered parallel structure. Each AC input is connected to a group of flyback conversion sub-circuits, and each group of conversion circuits includes four power conversion circuits, forming a total of twelve power conversion circuits, which significantly improves the power aggregation capability and output current carrying capacity of the circuit. Depending on the output topology, each rectifier diode can be connected in parallel with a uniformly set output filter capacitor, or grouped and connected with two output filter capacitors, thereby constructing a parallel output structure or a parallel-then-series output structure, which can flexibly adapt to different output voltage levels and load current requirements, thereby improving the output capacity of the whole machine and system compatibility.

[0058] In some embodiments, as Figure 1 As shown, the input power circuit includes an AC power supply and a rectifier circuit.

[0059] In the embodiments of this application, the AC power supply is a three-phase AC power supply. The rectifier circuit employs a three-phase bridge rectifier structure, with each phase consisting of four rectifier diodes. Each phase of the AC power supply is connected in series via two diodes, then in parallel, to achieve full-wave rectification. The rectifier circuit converts the three-phase AC power into a stable DC voltage, providing DC power for the subsequent flyback converter circuit.

[0060] In some embodiments, as Figure 1 As shown in FIG, when N=3, the input power supply includes: a three-phase AC power supply and three rectifier bridges. The three-phase output terminals of the three-phase AC power supply are connected to the input terminals of the three rectifier bridges respectively, and the two ends of the output side of the i-th rectifier bridge among the three rectifier bridges are connected to the i-th input filter capacitor C in Connect both ends of .

[0061] In the embodiment of the present application, the flyback conversion circuits are connected to the three-phase AC power supply, and each phase corresponds to a set of flyback conversion sub-circuits. ac 、V bc and V cc ) are connected in parallel. Each group of flyback conversion sub-circuits includes four power conversion circuits, for a total of twelve power conversion circuits.

[0062] In some embodiments, as Figure 1 As shown, the i-th output filter circuit includes a first output filter capacitor C o .

[0063] The first output filter capacitor C o The first end of the first output filter capacitor is connected to the cathode of all the first rectifier diodes of the M power conversion circuits in the i-th flyback conversion sub-circuit, and the second end of the i-th first output filter capacitor is connected to the second output end of the secondary winding of all the main transformers of the M power conversion circuits in the i-th flyback conversion sub-circuit. The first rectifier diodes are rectifier diodes B1 to B 12 .

[0064] In the embodiment of the present application, the first output filter capacitor C o The first ends of the rectifier diodes B1 to B 12 The negative pole of the first output filter capacitor C o The second end of the main transformer T1 to T 12 The second output end of the secondary winding is connected to form a parallel structure of the secondary rectifier output branch, thereby realizing parallel connection of the rectifier outputs of all twelve power conversion circuits, improving the power aggregation capability and output current carrying capacity of the circuit, thereby meeting the demand of high-power loads for high-efficiency output.

[0065] In some embodiments, as Figure 2 As shown, the i-th output filter circuit includes a first output filter capacitor C o and a second output filter capacitor C o1 .

[0066] The first output filter capacitor C o and the second output filter capacitor C o1 In series, the first output filter capacitor C o The first end is the first input end of the i-th output filter circuit, and the second output filter capacitor C o1 The first end of is the second input end of the i-th output filter circuit.

[0067] The cathode of at least one first rectifier diode of the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the first output filter capacitor C o The first end of the flyback conversion sub-circuit is connected to the cathode of at least one first rectifier diode of the M power conversion circuits in the i-th flyback conversion sub-circuit. o1 The first rectifier diodes are rectifier diodes B1 to B 12 .

[0068] like Figure 2 As shown, N=3, M=4, the cathodes of the two first rectifier diodes of the four power conversion circuits in each flyback conversion sub-circuit are connected to the first output filter capacitor C o The first end of the two first rectifier diodes corresponds to the second end of the secondary winding of the main transformer and the first output filter capacitor C o The second end of the rectifier diodes of the two first rectifier diodes of the four power conversion circuits in each flyback conversion sub-circuit is connected to the second output filter capacitor C o1 The second end of the secondary winding of the main transformer corresponding to the two first rectifier diodes and the first output filter capacitor C o1 The first end of the connection.

[0069] In the embodiment of the present application, the flyback conversion circuits are respectively connected to the three-phase AC power supply, and each phase is connected to a group of flyback conversion sub-circuits. Each group of flyback conversion sub-circuits includes four power conversion circuits, and a total of twelve power conversion circuits for the three phases are respectively provided with main transformers T1 to T 12 .

[0070] For example, the main transformers T1 to T 12 The output ends of the secondary windings are connected to the corresponding rectifier diodes B1 to B 12 The positive electrode of the first rectifier diodes B1, B2, B5, B6, B9 and B 10 Connect output filter capacitor C oThe first end of the output filter capacitor C o The second ends of the main transformers T1, T2, T5, T6, T9 and T 10 The input end of the secondary winding. The first rectifier diodes B3, B4, B7, B8, B 11 and B 12 Connect output filter capacitor C o The second output filter capacitor C o1 The first end of each transformer is connected to the main transformers T3, T4, T7, T8, T 11 and T 12 The input end of the secondary winding. Output filter capacitor C o and the output filter capacitor C o1 Further series connection forms a series topology of a rectifier output parallel structure of six power conversion circuits and another six-way rectifier output parallel structure, thereby improving the power aggregation capability and current carrying capacity of the whole machine while ensuring the output voltage level, meeting the actual needs of high-power loads for stable and efficient output.

[0071] In order to improve the energy conversion efficiency and overall reliability of the flyback converter circuit under high-frequency working conditions, and to solve the energy loss and device voltage stress problems caused by the release of leakage inductance energy at the moment when the main power switch tube of the traditional flyback converter is turned off, the present application provides a flyback converter circuit. By sharing the clamping capacitor in multiple power conversion circuits and combining the active absorption circuit composed of the switch tube, sub-transformer and rectifier diode, the centralized absorption and efficient recovery of the leakage inductance energy of the primary side of the main transformer are achieved. The above structure not only effectively improves the energy conversion efficiency of the circuit and reduces the stress burden of the power devices caused by the peak voltage, but also reduces the dependence of each parallel power conversion circuit on the capacity of the buffer device, further enhancing the operational stability of the entire flyback converter circuit under multi-path interleaved control.

[0072] In some embodiments, as Figure 3 As shown, when N=1, the input power supply includes an AC power supply and a rectifier bridge. The AC power supply is connected to the rectifier bridge, and the two ends of the output side of the rectifier bridge are respectively connected to the two ends of the i-th input filter capacitor.

[0073] In the embodiment of the present application, the flyback conversion circuit includes: a flyback conversion sub-circuit and an input power circuit, wherein the input end of the flyback conversion sub-circuit is connected to the output end of the input power circuit. The input power circuit includes: an AC power supply AC and a rectifier bridge H1.

[0074] The flyback conversion sub-circuit includes: input filter capacitor C in , clamping capacitor C1, output filter circuit, active absorption circuit and M power conversion circuits. The output filter circuit includes output filter capacitor Co . Wherein, M is a positive integer greater than or equal to 1, and M can be 4.

[0075] Exemplarily, the first of the four power conversion circuits in the flyback converter subcircuit includes a first switching transistor Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes a first switching transistor Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes a first switching transistor Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

[0076] Input filter capacitor C in The first end of each of the two terminals is connected to the first end of the primary winding of all the main transformers (such as T1, T2, T3 and T4) in the four power conversion circuits in the flyback conversion sub-circuit, and the input filter capacitor C in The second end is respectively connected to the first ends of all first switching tubes (such as Q1, Q2, Q3 and Q4) of the four power conversion circuits in the flyback conversion sub-circuit.

[0077] The first end of the clamping capacitor C1 is connected to the cathodes of all clamping diodes (e.g., A1, A2, A3, and A4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 is connected to the first end of the primary windings of all main transformers (e.g., T1, T2, T3, and T4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 can also be connected to the drains of all main power switching transistors (e.g., first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback conversion sub-circuit.

[0078] The drain of the first switching transistor Q1 is connected between the anode of the clamping diode A1 and the output end of the primary winding of the main transformer T1. The drain of the first switching transistor Q2 is connected between the anode of the clamping diode A2 and the output end of the primary winding of the main transformer T2. The drain of the first switching transistor Q3 is connected between the anode of the clamping diode A3 and the output end of the primary winding of the main transformer T3. The drain of the first switching transistor Q4 is connected between the anode of the clamping diode A4 and the output end of the primary winding of the main transformer T4.

[0079] The output end of the secondary winding of the main transformer T1 is connected to the anode of the first rectifier diode B1. The output end of the secondary winding of the main transformer T2 is connected to the anode of the first rectifier diode B2. The output end of the secondary winding of the main transformer T3 is connected to the anode of the first rectifier diode B3. The output end of the secondary winding of the main transformer T4 is connected to the anode of the first rectifier diode B4.

[0080] The cathode of the first rectifier diode (such as B1, B2, B3 and B4) in the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit o The first end of the load resistor Load is connected in parallel with the output filter capacitor C o Both ends.

[0081] The input end of the secondary winding of the main transformer (such as T1, T2, T3 and T4) of the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit o The second end of the

[0082] One input end of the active absorption circuit is connected in parallel to the common connection point between the clamping capacitor C1 and the clamping diodes A1, A2, A3, and A4. The other input end of the active absorption circuit is connected in parallel to the main power switch tubes Q1, Q2, Q3, and Q4 and the input filter capacitor C in Common connection point between.

[0083] The other input end of the active absorption circuit can also be connected in parallel to the primary windings of the main transformers T1, T2, T3 and T4 and the input filter capacitor C in Common connection point between.

[0084] According to the above embodiment, the above structure realizes the centralized absorption of leakage inductance energy in the flyback conversion circuit through the centralized clamping capacitors and active absorption circuit, thereby effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

[0085] In some possible instances, when N=2, that is, the input power supply circuit includes a two-phase AC power supply and two rectifier circuits, the two-phase output ends of the two-phase AC power supply are respectively connected to the input ends of the two rectifier circuits, and the output ends of the two rectifier circuits are connected to the input end of the input filter capacitor.

[0086] In some embodiments, the input power circuit includes a DC power source.

[0087] In some embodiments, as Figure 4 As shown, when N=1, the two ends of the DC power supply are respectively connected to the two ends of the i-th input filter capacitor.

[0088] In the embodiment of the present application, the flyback conversion circuit includes: a flyback conversion sub-circuit and an input power circuit, wherein the input end of the flyback conversion sub-circuit is connected to the output end of the input power circuit. The input power circuit includes a direct current power supply DC.

[0089] The flyback conversion sub-circuit includes: input filter capacitor C in, clamping capacitor C1, output filter circuit, active absorption circuit and M power conversion circuits. The output filter circuit includes output filter capacitor C o Wherein, M is a positive integer greater than or equal to 1, and can be a positive integer such as 1, 2, 3, 4, 5, 6, 7, 8, etc., and can be set according to actual power transmission efficiency or other actual conditions. M can be set to 4.

[0090] Exemplarily, the first of the four power conversion circuits in the flyback converter subcircuit includes a first switching transistor Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes a first switching transistor Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes a first switching transistor Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

[0091] Input filter capacitor C in The first end of each of the two terminals is connected to the first end of the primary winding of all the main transformers (such as T1, T2, T3 and T4) in the four power conversion circuits in the flyback conversion sub-circuit, and the input filter capacitor C in The second end is respectively connected to the first ends of all first switching tubes (such as Q1, Q2, Q3 and Q4) of the four power conversion circuits in the flyback conversion sub-circuit.

[0092] The first end of the clamping capacitor C1 is connected to the cathodes of all clamping diodes (e.g., A1, A2, A3, and A4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 is connected to the first end of the primary windings of all main transformers (e.g., T1, T2, T3, and T4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 can also be connected to the drains of all main power switching transistors (e.g., first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback conversion sub-circuit.

[0093] The drain of the first switching transistor Q1 is connected between the anode of the clamping diode A1 and the output end of the primary winding of the main transformer T1. The drain of the first switching transistor Q2 is connected between the anode of the clamping diode A2 and the output end of the primary winding of the main transformer T2. The drain of the first switching transistor Q3 is connected between the anode of the clamping diode A3 and the output end of the primary winding of the main transformer T3. The drain of the first switching transistor Q4 is connected between the anode of the clamping diode A4 and the output end of the primary winding of the main transformer T4.

[0094] The output end of the secondary winding of the main transformer T1 is connected to the anode of the first rectifier diode B1. The output end of the secondary winding of the main transformer T2 is connected to the anode of the first rectifier diode B2. The output end of the secondary winding of the main transformer T3 is connected to the anode of the first rectifier diode B3. The output end of the secondary winding of the main transformer T4 is connected to the anode of the first rectifier diode B4.

[0095] The cathode of the first rectifier diode (such as B1, B2, B3 and B4) in the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit o The first end of the load resistor Load is connected in parallel with the output filter capacitor C o Both ends.

[0096] The input end of the secondary winding of the main transformer (such as T1, T2, T3 and T4) of the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit o The second end of the

[0097] One input end of the active absorption circuit is connected in parallel to the common connection point between the clamping capacitor C1 and the clamping diodes A1, A2, A3, and A4. The other input end of the active absorption circuit is connected in parallel to the main power switch tubes Q1, Q2, Q3, and Q4 and the input filter capacitor C in Common connection point between.

[0098] The other input end of the active absorption circuit can also be connected in parallel to the primary windings of the main transformers T1, T2, T3 and T4 and the input filter capacitor C in Common connection point between.

[0099] According to the above embodiment, the above structure realizes the centralized absorption of leakage inductance energy in the flyback conversion circuit through the centralized clamping capacitors and active absorption circuit, thereby effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

[0100] In order to reduce the energy loss and spike voltage caused by the leakage inductance of the primary resistance of the transformer in the flyback conversion circuit, and at the same time improve the energy recovery efficiency and system reliability, the present application provides a flyback conversion circuit. The circuit forms a temporary storage path for leakage inductance energy by setting a clamping capacitor and a clamping diode, and further introduces an active absorption circuit, including a switch tube, a sub-transformer and a rectifier diode, to be turned on when the clamping capacitor voltage exceeds the preset threshold, and the leakage inductance energy temporarily stored in the clamping branch is converted and transmitted to the output side for recycling. Compared with the traditional circuit structure using passive clamping or energy loss type clamping, the present application effectively releases the magnetic flux energy and suppresses the leakage inductance spike during the shutdown period of the main transformer through the coordinated control of the main power switch tube and the active absorption circuit, thereby improving the energy utilization efficiency, alleviating the impact of voltage stress on the switching device, and improving the overall conversion efficiency and working stability of the circuit. It is particularly suitable for flyback topology application scenarios with high power density and high requirements for EBI control and device protection.

[0101] In some embodiments, the i-th active absorption circuit includes: a second switch tube Q a , sub-transformer T a and the second rectifier diode D a .

[0102] The i-th second switch tube Q a The first end of the ith input filter capacitor C in The first terminal or the i-th input filter capacitor C in The second end of the i-th second switch tube Q a The second end of the ith sub-transformer T a The first end of the primary winding is connected.

[0103] The i-th sub-transformer T a The second end of the primary winding and the first end of the i-th clamping capacitor C1.

[0104] The i-th sub-transformer T a The first end of the secondary winding and the i-th second rectifier diode D a The positive electrode of the i-th second rectifier diode D a The negative electrode of the output filter circuit is connected to at least one output filter capacitor C O The first end of the i-th sub-transformer T a The second end of the secondary winding is connected to at least one output filter capacitor C in the output filter circuit. O The second end of the

[0105] In some embodiments, in the i-th flyback conversion sub-circuit, when the second switch tube Q of each power conversion circuit of the M power conversion circuits is aDuring shutdown, the current in the primary winding of each power conversion circuit's main transformer is interrupted. A forward voltage is induced in the secondary winding of each power conversion circuit's main transformer, driving the first rectifier diode of each power conversion circuit into conduction. This allows the magnetic flux stored in each power conversion circuit's main transformer T1 to be output through the secondary winding of each power conversion circuit's main transformer T1 to the output filter circuit and load resistor.

[0106] The first switch tube of each power conversion circuit generates leakage inductance energy, and the leakage inductance energy is stored in the i-th clamping capacitor C1 through the clamping diode A1 of each power conversion circuit.

[0107] When the voltage of the i-th clamping capacitor C1 increases and exceeds a preset threshold value, the i-th active absorption circuit is turned on to transfer the leakage inductance energy to the output filter circuit and the load resistor.

[0108] In some embodiments, when the voltage of the i-th clamping capacitor C1 increases and exceeds a preset threshold value, the i-th second switch tube Q a The leakage inductance energy passes through the second switch tube Q a Then transmitted to the i-th sub-transformer T a The primary winding.

[0109] The secondary winding of the i-th sub-transformer induces a forward voltage, driving the i-th second rectifier diode D a It is turned on and transmits the leakage inductance energy to the output filter circuit and the load resistor.

[0110] In the embodiment of this application, Figure 5 As shown, when N=1, M=1, the flyback conversion circuit includes: a DC power supply DC, an input filter capacitor C in , clamping capacitor C1, power conversion circuit, active absorption circuit, output filter capacitor C o And load resistance Load.

[0111] The power conversion circuit includes: a clamping diode A1, a main power switch tube Q1 (ie, a first switch tube), a main transformer T1 and a rectifier diode B1.

[0112] The positive terminal of the DC power supply DC is connected to the input terminal of the primary winding of the main transformer T1. The negative terminal of the DC power supply DC is connected to the source terminal of the main power switch Q1. The negative terminal of the DC power supply DC and the source terminal of the main power switch Q1 are both grounded. The input filter capacitor C in Connected in parallel with the DC power supply.

[0113] The first end of the clamping capacitor C1 is connected to the cathode of the clamping diode A1, and the second end of the clamping capacitor C1 is connected to the first end of the primary winding of the main transformer T1. The second end of the clamping capacitor C1 can also be connected to the source of the main power switch Q1.

[0114] The drain of the main power switch Q1 is connected between the clamping diode A1 and the output end of the primary winding of the main transformer T1.

[0115] The output end of the secondary winding of the main transformer T1 is connected to the anode of the first rectifier diode B1. The cathode of the first rectifier diode B1 is connected to the output filter capacitor C o The first end of the secondary winding of the main transformer T1 is connected to the input end of the output filter capacitor C o The second end of the

[0116] like Figure 5 As shown, one input end of the active absorption circuit is connected between the clamping capacitor C1 and the clamping diode A1. The other input end of the active absorption circuit is connected between the primary winding of the main transformer T1 and the input filter capacitor C in The output end of the active absorption circuit is connected across the output filter capacitor C o both ends of .

[0117] like Figure 6 As shown, one input end of the active absorption circuit is connected between the clamping capacitor C1 and the clamping diode A1. The other input end of the active absorption circuit is connected between the main power switch Q1 and the input filter capacitor C in The output end of the active absorption circuit is connected across the output filter capacitor C o both ends of .

[0118] According to the above-described embodiment, by introducing a rationally structured set of clamping branches and active absorption paths into the flyback converter circuit, the leakage inductance energy of the main transformer's primary winding is effectively stored and actively recovered, significantly improving the circuit's energy conversion efficiency and the operating stability of the switching device. The clamping branch, constructed with the clamping capacitor and clamping diode, absorbs the high-frequency spike voltage caused by the leakage inductance on the primary winding side when the main power switch is turned off, preventing stress damage to the device caused by the spike and enhancing circuit reliability.

[0119] In some embodiments, as Figure 7 As shown, when N=1, M=1, the active absorption circuit includes: the second switch tube Q a , Sub-transformer T a and rectifier diode D a The active absorption circuit mentioned above can be any DC / DC circuit, and the present application is not limited thereto.

[0120] The second switch tube Q a The source is connected to the primary winding of the main transformer T1 and the input filter capacitor C in The second switch tube Q a The drain is connected to the sub-transformer T a The output end of the primary winding of the sub-transformer T a The input end of the primary winding is connected between the clamping capacitor C1 and the clamping diode A1.

[0121] like Figure 8 As shown, the second switch tube Q a The source can also be connected between the main power switch Q1 and the input filter capacitor C in between.

[0122] like Figure 7 As shown, the sub-transformer T a The input end of the secondary winding is connected to the secondary winding of the main transformer T1 and the output filter capacitor C o Between. Sub-transformer T a The output end of the secondary winding is connected to the rectifier diode D a The positive pole of the rectifier diode D a The negative electrode is connected to the rectifier diode B1 and the output filter capacitor C o between.

[0123] According to the above-described embodiment, by providing an active absorption circuit comprising a switching tube, a sub-transformer, and a rectifier diode, active conversion and efficient recovery of leakage inductance energy in the flyback converter circuit are achieved, thereby effectively alleviating the high-voltage spike problem caused by leakage inductance during the shutdown period of the main power switching tube. This active absorption circuit not only suppresses leakage inductance spikes and reduces clamping losses, but also improves the energy utilization efficiency of the flyback converter circuit. In addition, the input terminal of the secondary winding of the sub-transformer is connected between the secondary winding of the main transformer and the output filter capacitor, which helps maintain a stable reference potential on the secondary side and enhances circuit stability.

[0124] In some embodiments, as Figure 5 and Figure 6 As shown in the figure, when N=1, M=1 and the main power switch Q1 is turned on and the clamping diode A1 is in the off state, the input current generated by the DC power supply DC passes through the primary winding of the main transformer T1 and the drain of the main power switch Q1, so that magnetic flux is generated in the magnetic core of the main transformer T1. The rectifier diode B1 is in the off state, and the load resistor Load is connected to the output filter capacitor C o Provide electrical energy.

[0125] In the embodiment of the present application, when the main power switch Q1 is turned on, the anode of the clamping diode A1 is pulled close to ground potential, while the cathode of the clamping diode A1 remains at a high potential, resulting in a reverse voltage across the terminals of the clamping diode A1, effectively putting the clamping diode A1 in the off state. At this point, one end of the primary winding of the main transformer T1 is connected to the positive terminal (high potential) of the DC power supply DC, and the other end is connected to ground (low potential) through the main power switch Q1. This causes current to flow from the DC power supply DC through the primary winding of the main transformer T1 to ground, causing magnetic energy to accumulate in the magnetic core of the main transformer T1.

[0126] Since the polarity of the secondary winding of the main transformer T1 is opposite to that of the primary winding, during the conduction period of the main power switch Q1, the secondary winding of the main transformer T1 induces a reverse voltage, and the output end of the secondary winding of the main transformer T1 (connected to the anode of the rectifier diode B1) has a lower potential than the input end (connected to the output filter capacitor C o The potential of the rectifier diode B1 is reverse biased, that is, the rectifier diode B1 is in the cut-off state. At this time, the required power is supplied by the output filter capacitor C o Energy storage provided.

[0127] In some embodiments, as Figure 5 and Figure 6 As shown in the figure, when N=1, M=1 and the main power switch Q1 is turned off, the current in the primary winding of the main transformer T1 is instantly interrupted, and the magnetic energy stored in the magnetic core of the main transformer T1 is converted into an induced voltage, driving the secondary winding of the main transformer T1 to induce a forward voltage, causing the rectifier diode B1 to turn on, thereby outputting the magnetic flux (i.e., magnetic energy) stored in the main transformer T1 through the secondary winding of the main transformer T1 to the output filter capacitor C o And load resistance Load.

[0128] Due to the shutdown action of the main power switch tube Q1, the leakage inductance current in the primary winding of the main transformer T1 cannot be instantly interrupted, and a high-amplitude spike voltage is induced at both ends of the primary winding of the main transformer T1. This spike voltage puts the clamping diode A1 in a forward conduction state, and the leakage inductance current flows into the clamping capacitor C1 through the clamping diode A1, thereby storing the leakage inductance energy released by the primary winding of the main transformer T1 due to leakage inductance in the clamping capacitor C1 through the clamping diode A1. As the leakage inductance energy gradually accumulates, the voltage of the clamping capacitor C1 continues to rise. When the voltage of the clamping capacitor C1 increases and exceeds the preset threshold value, the active absorption circuit is turned on, transferring the leakage inductance energy to the output filter capacitor C o And load resistance Load.

[0129] In some embodiments, as Figure 7 As shown, when the voltage of the clamping capacitor C1 increases and exceeds the preset threshold value, the second switch tube Qa Controlled conduction, the leakage inductance energy stored in the clamp capacitor C1 is transferred through the second switch tube Q a The source of the second switch tube Q a The drain is transmitted to the sub-transformer T a The primary winding of the sub-transformer T a The secondary winding of the rectifier diode D a Forward conduction. The leakage inductance energy is generated by the sub-transformer T a The secondary winding output is connected to the rectifier diode D a Transmitted to the output filter capacitor C o and the load resistor Load to achieve effective recovery of the leakage inductance energy of the primary winding of the main transformer T1, thereby improving the overall energy conversion efficiency of the flyback conversion circuit.

[0130] According to the above-described embodiment, a structure combining a clamping capacitor and an active absorption circuit is employed to effectively absorb and recycle the leakage inductance energy of the primary side of the main transformer during the flyback conversion process. In conventional flyback conversion circuits, the leakage inductance energy generated at the moment the main power switch is turned off is typically released into the clamping resistor in the form of a high-amplitude spike voltage, which not only causes energy loss but also introduces significant voltage stress on the power devices, affecting the efficiency and reliability of the circuit. The present application uses a clamping diode to temporarily store the leakage inductance energy in the clamping capacitor. After the clamping capacitor voltage rises to a preset threshold value, the active absorption circuit is controlled to conduct, driving the sub-transformer to operate. This stored leakage inductance energy is transferred to the secondary winding of the sub-transformer via magnetic coupling. After being rectified by the rectifier diode, it is input into the output filter capacitor and the load resistor, thereby achieving energy reuse. The above-described circuit structure not only improves the energy conversion efficiency of the flyback conversion circuit, effectively suppresses the spike voltage of the main power devices, reduces the power capacity design requirements of the clamping capacitor and the active absorption circuit, but also enhances the stability and overall reliability of the circuit operation.

[0131] In order to solve the problems of low energy conversion efficiency, high device voltage stress, insufficient leakage inductance energy recovery, and difficult circuit structure integration in flyback conversion circuits under high-frequency operating conditions in multi-phase high-power density applications, the present application provides a flyback conversion circuit. The flyback conversion circuit is driven by multiple AC power sources and connected to three flyback conversion sub-circuits respectively. Each conversion circuit achieves unified absorption and efficient transmission of the leakage inductance energy of the primary side of the main transformer by sharing a clamping capacitor and combining a centralized active absorption circuit. At the same time, a multi-channel parallel output structure of the secondary winding inductive energy is adopted. In some embodiments, it supports connecting 12 output rectifier branches in parallel, or connecting 6 and 6 output rectifier branches in series, and uniformly rectifying and transmitting them to the output filter capacitor and load resistor, thereby improving the energy feedback efficiency. Compared with traditional discrete clamping and absorption solutions, the above structure supports multi-channel interleaved parallel connection and multi-phase input integrated design, effectively reducing the overall electromagnetic interference and device redundancy of the circuit, and improving the circuit thermal management capability and output voltage stability.

[0132] like Figure 9 and Figure 10 As shown, the flyback conversion circuit includes: A flyback conversion sub-circuits and an input power supply circuit, and the input end of each flyback conversion sub-circuit is connected to the output end of the input power supply circuit.

[0133] The ath flyback conversion sub-circuit includes: input filter capacitor C in , clamping capacitor C1, output filter circuit, active absorption circuit and B power conversion circuits, the output filter circuit includes at least one output filter capacitor C O Wherein, A is a positive integer greater than or equal to 1, B is a positive integer greater than or equal to 1, 1≤a≤A and a is a positive integer.

[0134] The bth power conversion circuit among the B power conversion circuits of the ath flyback conversion sub-circuit includes: a first switch tube Q1, a main transformer T1, a clamping diode A1 and a first rectifier diode B1, where 1≤b≤B and b is a positive integer.

[0135] The ath input filter capacitor C in The first end of each of the primary windings of the main transformers T1 of the B power conversion circuits in the a-th flyback conversion sub-circuit is connected to the first end of each of the primary windings of the main transformers T1 of the B power conversion circuits in the a-th flyback conversion sub-circuit. The a-th input filter capacitor C in The second end of is respectively connected to the first end of all the first switch tubes Q1 of the B power conversion circuits in the a-th flyback conversion sub-circuit.

[0136] The first end of the ath clamping capacitor C1 is respectively connected to the cathodes of all the clamping diodes A1 of the B power conversion circuits in the ath flyback conversion sub-circuit, and the second end of the ath clamping capacitor C1 is respectively connected to the first ends of the primary windings of all the main transformers T1 of the B power conversion circuits in the ath flyback conversion sub-circuit or respectively connected to the first ends of all the first switching tubes Q1 of the B power conversion circuits in the ath flyback conversion sub-circuit.

[0137] The second end of the j-th first switch tube Q1 is connected between the anode of the j-th clamping diode A1 and the second end of the primary winding of the j-th main transformer T1 .

[0138] The first end of the secondary winding of the jth main transformer T1 is connected to the anode of the jth first rectifier diode B1. The cathode of the first rectifier diode B1 in the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the at least one output filter capacitor C in the ath output filter circuit. O The first end of the secondary winding of the main transformer T1 of the B power conversion circuit in the a-th flyback conversion sub-circuit is connected to the second end of the secondary winding of the main transformer T1 of the B power conversion circuit in the a-th flyback conversion sub-circuit and at least one output filter capacitor C in the a-th output filter circuit O The second end of the

[0139] The first end of the ath active absorption circuit is connected between the ath clamping capacitor C1 and all the clamping diodes of the B power conversion circuits in the ath flyback conversion sub-circuit, and the second end of the ath active absorption circuit is connected to the ath input filter capacitor C in The third end of the ath active absorption circuit is connected to the ath input filter capacitor C in and between the first ends of all the first switching tubes of the B power conversion circuits in the ath flyback conversion sub-circuit.

[0140] According to the above embodiment, the energy efficiency improvement and modular integration of the flyback conversion circuit in high-power application scenarios are achieved through a three-phase multi-channel staggered parallel structure. Each AC input is connected to a group of flyback conversion sub-circuits, and each group of conversion circuits includes four power conversion circuits, forming a total of twelve power conversion circuits, which significantly improves the power aggregation capability and output current carrying capacity of the circuit. Depending on the output topology, each rectifier diode can be connected in parallel with a uniformly set output filter capacitor, or grouped and connected with two output filter capacitors, thereby constructing a parallel output structure or a parallel-then-series output structure, which can flexibly adapt to different output voltage levels and load current requirements, thereby improving the output capacity of the whole machine and system compatibility.

[0141] In some embodiments, as Figure 9 As shown, the input power circuit includes an AC power supply and a rectifier circuit.

[0142] In the embodiments of this application, the AC power supply is a three-phase AC power supply. The rectifier circuit employs a three-phase bridge rectifier structure, with each phase consisting of four rectifier diodes. Each phase of the AC power supply is connected in series via two diodes, then in parallel, to achieve full-wave rectification. The rectifier circuit converts the three-phase AC power into a stable DC voltage, providing DC power for the subsequent flyback converter circuit.

[0143] In some embodiments, as Figure 9 As shown in FIG, when A=3, the input power supply includes: a three-phase AC power supply and three rectifier bridges. The three-phase output terminals of the three-phase AC power supply are connected to the input terminals of the three rectifier bridges respectively, and the two ends of the output side of the a-th rectifier bridge among the three rectifier bridges are connected to the a-th input filter capacitor C in Connect both ends of .

[0144] In the embodiment of the present application, the flyback conversion circuits are connected to the three-phase AC power supply, and each phase corresponds to a set of flyback conversion sub-circuits. ac 、V bc and V cc ) are connected in parallel. Each group of flyback conversion sub-circuits includes four power conversion circuits, for a total of twelve power conversion circuits.

[0145] In some embodiments, as Figure 9 As shown, the ath output filter circuit includes a first output filter capacitor C o .

[0146] The first output filter capacitor C o The first end of is connected to the cathode of all the first rectifier diodes of the B power conversion circuits in the a-th flyback conversion sub-circuit, and the second end of the a-th first output filter capacitor is connected to the second output end of the secondary winding of all the main transformers of the B power conversion circuits in the a-th flyback conversion sub-circuit. 12 .

[0147] In the embodiment of the present application, the first output filter capacitor C o The first ends of the rectifier diodes B1 to B 12 The negative pole of the first output filter capacitor C o The second end of the main transformer T1 to T 12The second output end of the secondary winding is connected to form a parallel structure of the secondary rectifier output branch, thereby realizing parallel connection of the rectifier outputs of all twelve power conversion circuits, improving the power aggregation capability and output current carrying capacity of the circuit, thereby meeting the demand of high-power loads for high-efficiency output.

[0148] In some embodiments, as Figure 10 As shown, the ath output filter circuit includes a first output filter capacitor C o and a second output filter capacitor C o1 .

[0149] The first output filter capacitor C o and the second output filter capacitor C o1 In series, the first output filter capacitor C o The first end is the first input end of the ath output filter circuit, and the second output filter capacitor C o1 The first end of is the second input end of the ath output filter circuit.

[0150] The cathode of at least one first rectifier diode of the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the first output filter capacitor C o The first end of the flyback conversion sub-circuit is connected to the cathode of at least one first rectifier diode of the B power conversion circuits in the a-th flyback conversion sub-circuit. o1 The first rectifier diodes are rectifier diodes B1 to B 12 .

[0151] In the embodiment of the present application, the flyback conversion circuits are respectively connected to the three-phase AC power supply, and each phase is connected to a group of flyback conversion sub-circuits. Each group of flyback conversion sub-circuits includes four power conversion circuits, and a total of twelve power conversion circuits for the three phases are respectively provided with main transformers T1 to T 12 .

[0152] For example, the main transformers T1 to T 12 The output ends of the secondary windings are connected to the corresponding rectifier diodes B1 to B 12 The positive electrode of the first rectifier diodes B1, B2, B5, B6, B9 and B 10 Connect output filter capacitor C o The first end of the output filter capacitor C o The second ends of the main transformers T1, T2, T5, T6, T9 and T 10 The input end of the secondary winding. The first rectifier diodes B3, B4, B7, B8, B 11 and B 12 Connect output filter capacitor C o The second output filter capacitor Co1 The first end of each transformer is connected to the main transformers T3, T4, T7, T8, T 11 and T 12 The input end of the secondary winding. Output filter capacitor C o and the output filter capacitor C o1 Further series connection forms a series topology of a rectifier output parallel structure of six power conversion circuits and another six-way rectifier output parallel structure, thereby improving the power aggregation capability and current carrying capacity of the whole machine while ensuring the output voltage level, meeting the actual needs of high-power loads for stable and efficient output.

[0153] In order to improve the energy conversion efficiency and overall reliability of the flyback converter circuit under high-frequency working conditions, and to solve the energy loss and device voltage stress problems caused by the release of leakage inductance energy at the moment when the main power switch tube of the traditional flyback converter is turned off, the present application provides a flyback converter circuit. By sharing the clamping capacitor in multiple power conversion circuits and combining the active absorption circuit composed of the switch tube, sub-transformer and rectifier diode, the centralized absorption and efficient recovery of the leakage inductance energy of the primary side of the main transformer are achieved. The above structure not only effectively improves the energy conversion efficiency of the circuit and reduces the stress burden of the power devices caused by the peak voltage, but also reduces the dependence of each parallel power conversion circuit on the capacity of the buffer device, further enhancing the operational stability of the entire flyback converter circuit under multi-path interleaved control.

[0154] In some embodiments, as Figure 11 As shown, when A=1, the input power supply includes an AC power supply AC and a rectifier bridge. The AC power supply is connected to the rectifier bridge, and the two ends of the output side of the rectifier bridge are respectively connected to the two ends of the ath input filter capacitor.

[0155] In the embodiment of the present application, the flyback conversion circuit includes: a flyback conversion sub-circuit and an input power circuit, wherein the input end of the flyback conversion sub-circuit is connected to the output end of the input power circuit. The input power circuit includes: an AC power supply AC and a rectifier bridge H1. The AC power supply AC is connected across the bridge arm of the rectifier bridge H1, and the rectifier bridge H1 and the input filter capacitor C in in parallel.

[0156] The flyback conversion sub-circuit includes: input filter capacitor C in , clamping capacitor C1, output filter circuit, active absorption circuit and B power conversion circuits. The output filter circuit includes output filter capacitor C o Wherein, B is a positive integer greater than or equal to 1, and B is preferably 4.

[0157] Exemplarily, the first of the four power conversion circuits in the flyback converter subcircuit includes a first switching transistor Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes a first switching transistor Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes a first switching transistor Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

[0158] Input filter capacitor C in The first end of each of the two terminals is connected to the first end of the primary winding of all the main transformers (such as T1, T2, T3 and T4) in the four power conversion circuits in the flyback conversion sub-circuit, and the input filter capacitor C in The second end is respectively connected to the first ends of all first switching tubes (such as Q1, Q2, Q3 and Q4) of the four power conversion circuits in the flyback conversion sub-circuit.

[0159] The first end of the clamping capacitor C1 is connected to the cathodes of all clamping diodes (e.g., A1, A2, A3, and A4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 is connected to the first end of the primary windings of all main transformers (e.g., T1, T2, T3, and T4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 can also be connected to the drains of all main power switching transistors (e.g., first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback conversion sub-circuit.

[0160] The drain of the first switching transistor Q1 is connected between the anode of the clamping diode A1 and the output end of the primary winding of the main transformer T1. The drain of the first switching transistor Q2 is connected between the anode of the clamping diode A2 and the output end of the primary winding of the main transformer T2. The drain of the first switching transistor Q3 is connected between the anode of the clamping diode A3 and the output end of the primary winding of the main transformer T3. The drain of the first switching transistor Q4 is connected between the anode of the clamping diode A4 and the output end of the primary winding of the main transformer T4.

[0161] The output end of the secondary winding of the main transformer T1 is connected to the anode of the first rectifier diode B1. The output end of the secondary winding of the main transformer T2 is connected to the anode of the first rectifier diode B2. The output end of the secondary winding of the main transformer T3 is connected to the anode of the first rectifier diode B3. The output end of the secondary winding of the main transformer T4 is connected to the anode of the first rectifier diode B4.

[0162] The cathode of the first rectifier diode (such as B1, B2, B3 and B4) in the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit oThe first end of the load resistor Load is connected in parallel with the output filter capacitor C o Both ends.

[0163] The input end of the secondary winding of the main transformer (such as T1, T2, T3 and T4) of the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit o The second end of the

[0164] The first end of the active absorption circuit is connected to the common connection point between the clamping capacitor C1 and the clamping diodes A1, A2, A3 and A4. The second end of the active absorption circuit is connected to the primary windings of the main transformers T1, T2, T3 and T4 and the input filter capacitor C in The third end of the active absorption circuit is connected to the main power switch tube Q1, the main power switch tube Q2, the main power switch tube Q3 and the main power switch tube Q4 and the input filter capacitor C in Common connection point between.

[0165] According to the above embodiment, the above structure realizes the centralized absorption of leakage inductance energy in the flyback conversion circuit through the centralized clamping capacitors and active absorption circuit, thereby effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

[0166] In some possible instances, when A=2, that is, the input power supply circuit includes a two-phase AC power supply and two rectifier circuits, the two-phase output ends of the two-phase AC power supply are respectively connected to the input ends of the two rectifier circuits, and the output ends of the two rectifier circuits are connected to the input end of the input filter capacitor.

[0167] In some embodiments, the input power circuit includes a DC power source.

[0168] In some embodiments, as Figure 12 As shown, when A=1, the two ends of the DC power supply are respectively connected to the two ends of the ath input filter capacitor.

[0169] In the embodiment of the present application, the flyback conversion circuit includes: a flyback conversion sub-circuit and an input power circuit, wherein the input end of the flyback conversion sub-circuit is connected to the output end of the input power circuit. The input power circuit includes a direct current power supply DC.

[0170] The flyback conversion sub-circuit includes: input filter capacitor C in , clamping capacitor C1, output filter circuit, active absorption circuit and B power conversion circuits. The output filter circuit includes output filter capacitor C oWherein, B is a positive integer greater than or equal to 1, and B can be a positive integer such as 1, 2, 3, 4, 5, 6, 7, 8, etc., and can be set according to actual power transmission efficiency or other actual conditions. B can be 4.

[0171] Exemplarily, the first of the four power conversion circuits in the flyback converter subcircuit includes a first switching transistor Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes a first switching transistor Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes a first switching transistor Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

[0172] Input filter capacitor C in The first end of each of the two terminals is connected to the first end of the primary winding of all the main transformers (such as T1, T2, T3 and T4) in the four power conversion circuits in the flyback conversion sub-circuit, and the input filter capacitor C in The second end is respectively connected to the first ends of all first switching tubes (such as Q1, Q2, Q3 and Q4) of the four power conversion circuits in the flyback conversion sub-circuit.

[0173] The first end of the clamping capacitor C1 is connected to the cathodes of all clamping diodes (e.g., A1, A2, A3, and A4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 is connected to the first end of the primary windings of all main transformers (e.g., T1, T2, T3, and T4) in the four power conversion circuits of the flyback conversion sub-circuit. The second end of the clamping capacitor C1 can also be connected to the drains of all main power switching transistors (e.g., first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback conversion sub-circuit.

[0174] The drain of the first switching transistor Q1 is connected between the anode of the clamping diode A1 and the output end of the primary winding of the main transformer T1. The drain of the first switching transistor Q2 is connected between the anode of the clamping diode A2 and the output end of the primary winding of the main transformer T2. The drain of the first switching transistor Q3 is connected between the anode of the clamping diode A3 and the output end of the primary winding of the main transformer T3. The drain of the first switching transistor Q4 is connected between the anode of the clamping diode A4 and the output end of the primary winding of the main transformer T4.

[0175] The output end of the secondary winding of the main transformer T1 is connected to the anode of the first rectifier diode B1. The output end of the secondary winding of the main transformer T2 is connected to the anode of the first rectifier diode B2. The output end of the secondary winding of the main transformer T3 is connected to the anode of the first rectifier diode B3. The output end of the secondary winding of the main transformer T4 is connected to the anode of the first rectifier diode B4.

[0176] The cathode of the first rectifier diode (such as B1, B2, B3 and B4) in the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit o The first end of the load resistor Load is connected in parallel with the output filter capacitor C o Both ends.

[0177] The input end of the secondary winding of the main transformer (such as T1, T2, T3 and T4) of the four power conversion circuits in the flyback conversion subcircuit and the output filter capacitor C in the output filter circuit o The second end of the

[0178] The first end of the active absorption circuit is connected to the common connection point between the clamping capacitor C1 and the clamping diodes A1, A2, A3 and A4. The second end of the active absorption circuit is connected to the primary windings of the main transformers T1, T2, T3 and T4 and the input filter capacitor C in The third end of the active absorption circuit is connected to the main power switch tube Q1, the main power switch tube Q2, the main power switch tube Q3 and the main power switch tube Q4 and the input filter capacitor C in Common connection point between.

[0179] According to the above embodiment, the above structure realizes the centralized absorption of leakage inductance energy in the flyback conversion circuit through the centralized clamping capacitors and active absorption circuit, thereby effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

[0180] In some embodiments, the present application also provides a flyback conversion circuit, such as Figure 13 As shown, the flyback conversion circuit includes: a DC power supply DC, an input filter capacitor C in , clamping capacitor C1, power conversion circuit, active absorption circuit, output filter capacitor C o And load resistance Load.

[0181] The power conversion circuit includes: a clamping diode A1, a main power switch tube Q1, a main transformer T1 and a rectifier diode B1.

[0182] The positive pole of the DC power supply DC is connected to the input end of the primary winding of the main transformer T1. The negative pole of the DC power supply DC is connected to the source of the main power switch Q1. The negative pole of the DC power supply DC and the source of the main power switch Q1 are both grounded. The input filter capacitor C in Connected in parallel with the DC power supply.

[0183] A first end of the clamping capacitor C1 is connected to the cathode of the clamping diode A1 , and a second end of the clamping capacitor C1 is connected to a first end of the primary winding of the main transformer T1 .

[0184] like Figure 14 As shown, the second end of the clamping capacitor C1 may also be connected to the drain of the main power switch tube (such as the first switch tube Q1).

[0185] The drain of the main power switch Q1 is connected between the clamping diode A1 and the output end of the primary winding of the main transformer T1.

[0186] The output end of the secondary winding of the main transformer T1 is connected to the positive electrode of the first rectifier diode B1. The negative electrode of the first rectifier diode B1 is connected to the output filter capacitor C in the output filter circuit. o The first end of the load resistor Load is connected in parallel with the output filter capacitor C o Both ends.

[0187] The first end of the active absorption circuit is connected between the clamping capacitor C1 and the clamping diode A1. The second end of the active absorption circuit is connected between the primary winding of the main transformer T1 and the input filter capacitor C in The third terminal of the active absorption circuit is connected to the main power switch Q1 and the input filter capacitor C in between.

[0188] In some embodiments, the present application also provides a flyback conversion circuit, such as Figure 15 As shown, the flyback conversion circuit includes: a DC power supply DC, an input filter capacitor C in , clamping capacitor C1, inductor L k , power conversion circuit, active snubber circuit (Active snubber_1), output filter capacitor C o And load resistance Load.

[0189] The power conversion circuit includes: a clamping diode A1, a main power switch tube Q1, a main transformer T1 and a rectifier diode B1.

[0190] The positive electrode of the DC power supply DC is connected between the input end of the primary winding of the main transformer T1 and the clamping capacitor C1. The negative electrode of the DC power supply DC is connected to the source of the main power switch Q1. The negative electrode of the DC power supply DC and the source of the main power switch Q1 are both grounded. The input filter capacitor C in The output end of the primary winding of the main transformer T1 is connected to the inductor L k Series connection.

[0191] The clamping capacitor C1 and the clamping diode A1 are connected in series and then connected in parallel with the primary winding of the main transformer T1.

[0192] The first end of the clamping capacitor C1 is connected to the cathode of the clamping diode A1, and the second end of the clamping capacitor C1 is connected to the first end of the primary winding of the main transformer T1. The drain of the main power switch Q1 is connected to the cathode of the clamping diode A1 and the inductor L. k between.

[0193] The output end of the secondary winding of the main transformer T1 is connected to the positive electrode of the first rectifier diode B1. The negative electrode of the first rectifier diode B1 is connected to the output filter capacitor C in the output filter circuit. o The first end of the load resistor Load is connected in parallel with the output filter capacitor C o Both ends.

[0194] The active absorption circuit includes a second switch tube Q a 、Inductor L a and rectifier diode D a The second switch tube Q a With the rectifier diode D a After the series connection, one end is connected between the clamping capacitor C1 and the clamping diode A1, and the other end is connected between the main power switch tube Q1 and the input filter capacitor C in between.

[0195] Inductor L a One end is connected to the second switch tube Q a With the rectifier diode D a The other end is connected between the clamp capacitor C1 and the input filter capacitor C in between.

[0196] In some embodiments, as Figure 15 As shown, when the main power switch Q1 is turned off, the inductor L connected to the primary winding of the main transformer T1 is k The leakage current in the main transformer T1 cannot be interrupted instantly, and a high-amplitude spike voltage is induced at both ends of the primary winding of the main transformer T1. This spike voltage puts the clamping diode A1 into the forward conduction state, and the leakage current flows into the clamping capacitor C1 through the clamping diode A1, thereby storing the leakage inductance energy released by the primary winding of the main transformer T1 due to leakage inductance in the clamping capacitor C1 through the clamping diode A1. As the leakage inductance energy gradually accumulates, the voltage of the clamping capacitor C1 continues to rise. When the voltage of the clamping capacitor C1 increases and exceeds the preset threshold value, the active absorption circuit is turned on, transferring the leakage inductance energy to the input filter capacitor C in .

[0197] When the voltage of the clamping capacitor C1 increases and exceeds the preset threshold value, the second switch tube Q a Controlled conduction, the leakage inductance energy stored in the clamp capacitor C1 is transferred through the second switch tube Q a The source of the second switch tube Q aThe drain is transferred to the inductor L a Inductor L a After energy storage, the rectifier diode D a Forward conduction allows the leakage inductance energy to pass through the rectifier diode D a Transmitted to the input filter capacitor C in , in order to achieve effective recovery of the leakage inductance energy of the primary winding of the main transformer T1, and improve the overall energy conversion efficiency of the flyback conversion circuit.

[0198] According to the above-described embodiment, the clamping branch, comprised of a clamping capacitor and a clamping diode, effectively suppresses the high-amplitude voltage spike caused by leakage inductance energy at the moment of shutdown of the main power switch, thereby improving the stability of circuit operation and the reliability of the power device. Furthermore, an active absorption circuit, comprised of a switch, an inductor, and a rectifier diode, enables active regulation and transmission of energy in the clamping branch. Through electromagnetic coupling, the clamped energy is effectively transferred to the primary output, avoiding the direct energy consumption in the clamping resistor in traditional clamping methods and improving the circuit's energy utilization efficiency. Furthermore, by providing an inductor element in series with the primary circuit of the main transformer, the energy transfer path is optimized, transient current spikes are suppressed, and electromagnetic compatibility and system efficiency under high-frequency operating conditions are further improved.

[0199] For example, Figure 16 The diagram is a timing control diagram of the main power switch tube in the flyback conversion circuit, which is applied to the above-mentioned flyback conversion circuit.

[0200] In such Figure 16 In the timing control shown, the four main power switches Q1, Q2, Q3, and Q4 are turned on alternately in a fixed cycle. The conduction pulse duration of each main power switch is the same, and the conduction start times of two adjacent main power switches are staggered by 90 electrical degrees, thereby forming an equally spaced staggered control mode.

[0201] For example, the main power switch Q1 is turned on first. Before the conduction period of the main power switch Q1 ends, the main power switch Q3 enters the conduction state, followed by the main power switch Q2, and then the main power switch Q4, and the cycle continues in sequence.

[0202] According to the above-described embodiment, the interleaved conduction control method enables the current outputs of the four power conversion circuits to be complementary and interleaved in the time domain, effectively suppressing output current ripple, reducing current surges on the input side, and improving the system's transient response performance. This interleaved conduction control method also achieves balanced load distribution across the power conversion circuits, significantly improving the overall circuit's power conversion efficiency and enhancing the flyback converter circuit's electromagnetic compatibility performance under high-frequency operating conditions.

[0203] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A flyback converter circuit, characterized in that: include: N flyback conversion sub-circuits and an input power supply circuit, wherein the input end of each flyback conversion sub-circuit is connected to the output end of the input power supply circuit; The i-th flyback conversion sub-circuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and M power conversion circuits, wherein the output filter circuit includes at least one output filter capacitor; wherein N is a positive integer greater than or equal to 1, M is a positive integer greater than or equal to 1, 1≤i≤N, and i is a positive integer; The j-th power conversion circuit among the M power conversion circuits of the i-th flyback conversion sub-circuit includes: a first switch tube, a main transformer, a clamping diode and a first rectifier diode, wherein 1≤j≤M and j is a positive integer; The first end of the i-th input filter capacitor is respectively connected to the first end of the primary winding of all the main transformers of the M power conversion circuits in the i-th flyback conversion sub-circuit, and the second end of the i-th input filter capacitor is respectively connected to the first end of all the first switching tubes of the M power conversion circuits in the i-th flyback conversion sub-circuit; The first end of the i-th clamping capacitor is respectively connected to the cathodes of all clamping diodes of the M power conversion circuits in the i-th flyback conversion sub-circuit, and the second end of the i-th clamping capacitor is respectively connected to the first ends of the primary windings of all main transformers of the M power conversion circuits in the i-th flyback conversion sub-circuit or respectively connected to the first ends of all first switching transistors of the M power conversion circuits in the i-th flyback conversion sub-circuit; The second end of the jth first switching tube is connected between the anode of the jth clamping diode and the second end of the primary winding of the jth main transformer; The first end of the secondary winding of the jth main transformer is connected to the anode of the jth first rectifier diode; the cathode of the first rectifier diode in the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the first end of at least one output filter capacitor in the i-th output filter circuit; the second end of the secondary winding of the main transformer of the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the second end of at least one output filter capacitor in the i-th output filter circuit; The first input end of the i-th active absorption circuit is connected to the first end of the i-th clamping capacitor, the second input end of the i-th active absorption circuit is connected to the first end of the i-th input filter capacitor or the second end of the i-th input filter capacitor, the first output end of the i-th active absorption circuit is connected to the first input end of the i-th output filter circuit, and the second output end of the i-th active absorption circuit is connected to the second input end of the i-th output filter circuit.

2. The flyback converter circuit according to claim 1, wherein: The i-th active absorption circuit includes: a second switching tube, a sub-transformer and a second rectifier diode; The first end of the i-th second switching tube is connected to the first end of the i-th input filter capacitor or the second end of the i-th input filter capacitor, and the second end of the i-th second switching tube is connected to the first end of the primary winding of the i-th sub-transformer; The second end of the primary winding of the i-th sub-transformer is connected to the first end of the i-th clamping capacitor; The first end of the secondary winding of the i-th sub-transformer is connected to the positive electrode of the i-th second rectifier diode, the negative electrode of the i-th second rectifier diode is connected to the first end of at least one output filter capacitor of the output filter circuit, and the second end of the secondary winding of the i-th sub-transformer is connected to the second end of at least one output filter capacitor in the output filter circuit.

3. The flyback converter circuit according to claim 2, wherein: In the i-th flyback conversion sub-circuit, when the first switch tube of each of the M power conversion circuits is turned off, the current in the primary winding of the main transformer of each power conversion circuit is interrupted; the secondary winding of the main transformer of each power conversion circuit induces a forward voltage, driving the first rectifier diode of each power conversion circuit to conduct, so that the magnetic flux stored in the main transformer of each power conversion circuit is output to the output filter circuit and the load resistor through the secondary winding of the main transformer of each power conversion circuit; The first switch tube of each power conversion circuit generates leakage inductance energy, and the leakage inductance energy is stored in the i-th clamping capacitor through the clamping diode of each power conversion circuit; When the voltage of the i-th clamping capacitor increases and exceeds a preset threshold value, the i-th active absorption circuit is turned on, so that the leakage inductance energy is transmitted to the output filter circuit and the load resistor.

4. The flyback converter circuit according to claim 3, wherein: When the voltage of the i-th clamping capacitor increases and exceeds a preset threshold value, the i-th second switch tube is turned on, and the leakage inductance energy is transmitted to the primary winding of the i-th sub-transformer after passing through the i-th second switch tube; The secondary winding of the i-th sub-transformer induces a forward voltage, driving the i-th second rectifier diode to conduct, so that the leakage inductance energy is transmitted to the output filter circuit and the load resistor.

5. The flyback converter circuit according to any one of claims 1 to 4, characterized in that: The input power circuit includes a DC power supply.

6. The flyback converter circuit according to any one of claims 1 to 4, characterized in that: The input power circuit includes an AC power supply and a rectifier circuit.

7. The flyback converter circuit according to claim 5, wherein: When N=1, the two ends of the DC power supply are respectively connected to the two ends of the i-th input filter capacitor.

8. The flyback converter circuit according to claim 6, wherein: When N=1, the input power supply includes an AC power supply and a rectifier bridge; the AC power supply is connected to the rectifier bridge, and the two ends of the output side of the rectifier bridge are respectively connected to the two ends of the i-th input filter capacitor.

9. The flyback converter circuit according to claim 6, wherein: When N=3; the input power supply includes: 1 three-phase AC power supply and 3 rectifier bridges; the three-phase output ends of the three-phase AC power supply are respectively connected to the input ends of the three rectifier bridges, and the two ends of the output side of the i-th rectifier bridge among the three rectifier bridges are respectively connected to the two ends of the i-th input filter capacitor.

10. The flyback converter circuit according to any one of claims 1 to 4, characterized in that: The i-th output filter circuit includes a first output filter capacitor; The first end of the first output filter capacitor is respectively connected to the negative electrodes of all the first rectifier diodes of the M power conversion circuits in the i-th flyback conversion sub-circuit, and the second end of the i-th first output filter capacitor is connected to the second output end of the secondary winding of all the main transformers of the M power conversion circuits in the i-th flyback conversion sub-circuit.

11. The flyback converter circuit according to any one of claims 1 to 4, characterized in that: The i-th output filter circuit includes a first output filter capacitor and a second output filter capacitor; The first output filter capacitor and the second output filter capacitor are connected in series, the first end of the first output filter capacitor is the first input end of the i-th output filter circuit, and the first end of the second output filter capacitor is the second input end of the i-th output filter circuit; The cathode of at least one first rectifier diode of the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the first end of the first output filter capacitor, and the cathode of at least one first rectifier diode of the M power conversion circuits in the i-th flyback conversion sub-circuit is connected to the second end of the second output filter capacitor.

12. A flyback converter circuit, characterized in that: include: A flyback conversion sub-circuit and an input power supply circuit, wherein the input end of each flyback conversion sub-circuit is connected to the output end of the input power supply circuit; The ath flyback conversion subcircuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and B power conversion circuits, wherein the output filter circuit includes at least one output filter capacitor; wherein A is a positive integer greater than or equal to 1 and B is a positive integer greater than or equal to 1, or A is a positive integer greater than or equal to 2 and B is a positive integer greater than or equal to 1, 1≤a≤A, and a is a positive integer; The bth power conversion circuit among the B power conversion circuits of the ath flyback conversion sub-circuit comprises: a first switch tube, a main transformer, a clamping diode and a first rectifier diode, wherein 2≤b≤B and b is a positive integer; The first end of the ath input filter capacitor is respectively connected to the first end of the primary winding of all the main transformers of the B power conversion circuits in the ath flyback conversion sub-circuit, and the second end of the ath input filter capacitor is respectively connected to the first end of all the first switching tubes of the B power conversion circuits in the ath flyback conversion sub-circuit; The first end of the ath clamping capacitor is respectively connected to the cathodes of all clamping diodes of the B power conversion circuits in the ath flyback conversion sub-circuit, and the second end of the ath clamping capacitor is respectively connected to the first ends of the primary windings of all main transformers of the B power conversion circuits in the ath flyback conversion sub-circuit or respectively connected to the first ends of all first switching transistors of the B power conversion circuits in the ath flyback conversion sub-circuit; The second end of the bth first switching tube is connected between the bth clamping diode and the second end of the bth primary winding of the main transformer; The first end of the secondary winding of the bth main transformer is connected to the positive electrode of the bth first rectifier diode; the cathode of the first rectifier diode in the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the first end of the at least one output filter capacitor in the ath output filter circuit, and the second end of the secondary winding of the main transformer in the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the second end of the at least one output filter capacitor in the ath output filter circuit; The first end of the ath active absorption circuit is connected between the ath clamping capacitor and all the clamping diodes of the B power conversion circuits in the ath flyback conversion sub-circuit, the second end of the ath active absorption circuit is connected between the ath input filter capacitor and the first end of the primary winding of all the main transformers of the B power conversion circuits in the ath flyback conversion sub-circuit, and the third end of the ath active absorption circuit is connected between the ath input filter capacitor and the first end of all the first switching tubes of the B power conversion circuits in the ath flyback conversion sub-circuit.

13. The flyback converter circuit according to claim 12, wherein: The input power circuit includes a DC power supply.

14. The flyback converter circuit according to claim 12, wherein: The input power circuit includes an AC power supply and a rectifier circuit.

15. The flyback converter circuit according to claim 13, wherein: When N=1, the two ends of the DC power supply are respectively connected to the two ends of the ath input filter capacitor.

16. The flyback converter circuit according to claim 14, wherein: When N=1, the input power supply includes an AC power supply and a rectifier bridge; the AC power supply is connected to the rectifier bridge, and the two ends of the output side of the rectifier bridge are respectively connected to the two ends of the ath input filter capacitor.

17. The flyback converter circuit according to claim 13, wherein: When N=3; the input power supply includes: 1 three-phase AC power supply and 3 rectifier bridges; the three-phase output ends of the three-phase AC power supply are respectively connected to the input ends of the three rectifier bridges, and the two ends of the output side of the ath rectifier bridge among the three rectifier bridges are respectively connected to the two ends of the i-th input filter capacitor.

18. The flyback converter circuit according to any one of claims 12 to 17, characterized in that: The output filter circuit a-th comprises a first output filter capacitor; The first end of the first output filter capacitor is respectively connected to the negative electrodes of all the first rectifier diodes of the B power conversion circuits in the a-th flyback conversion sub-circuit, and the second end of the a-th first output filter capacitor is connected to the second output end of the secondary winding of all the main transformers of the B power conversion circuits in the a-th flyback conversion sub-circuit.

19. The flyback converter circuit according to any one of claims 12 to 17, wherein: The output filter circuit a-th comprises a first output filter capacitor and a second output filter capacitor; The first output filter capacitor and the second output filter capacitor are connected in series, the first end of the first output filter capacitor is the first input end of the a-th output filter circuit, and the first end of the second output filter capacitor is the second input end of the a-th output filter circuit; The cathode of at least one first rectifier diode of the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the first end of the first output filter capacitor, and the cathode of at least one first rectifier diode of the B power conversion circuits in the ath flyback conversion sub-circuit is connected to the second end of the second output filter capacitor.

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