Flyback converter circuit

Abstract

This application discloses a flyback converter circuit, which includes N flyback converter sub-circuits and an input power supply circuit. The input terminal of each flyback converter sub-circuit is connected to the output terminal of the input power supply circuit. Each flyback converter sub-circuit includes an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and M power conversion circuits. The first input terminal of the active absorption circuit is connected to the first terminal of the clamping capacitor, the second input terminal of the active absorption circuit is connected to either the first or second terminal of the input filter capacitor, the first output terminal of the active absorption circuit is connected to the first input terminal of the output filter circuit, and the second output terminal of the active absorption circuit is connected to the second input terminal of the output filter circuit. By employing multi-path interleaved conduction control and a unified energy absorption design, the power conversion efficiency and power density of the circuit can be effectively improved, the voltage stress on the devices can be reduced, and the electromagnetic compatibility performance can be improved.

Description

Technical Field

[0001] This application relates to the field of power electronic conversion technology, and in particular to a flyback converter circuit. Background Technology

[0002] The flyback converter, a typical isolated DC-DC converter topology, is widely used in small and medium power supply systems due to its simple structure, flexible control, small number of components, high system reliability, and low cost. It is particularly suitable for applications such as mobile phone chargers, small household appliance adapters, and auxiliary power supplies in industrial equipment. This type of converter achieves electrical isolation between input and output by not simultaneously conducting the primary and secondary windings of the transformer, and utilizes the transformer core for energy storage, achieving isolated energy transfer without the need for an additional air gap structure.

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

[0004] To further expand the application capabilities of flyback converters in medium-to-high power scenarios and alleviate interference caused by input and output current ripple, existing technologies have proposed solutions using interleaved parallel topologies. By implementing staggered phase control for multiple flyback converter units, power output capability can be improved while effectively enhancing current continuity and reducing system electromagnetic interference. However, with the increase in the number of parallel paths, voltage spikes caused by transformer leakage inductance and the resulting energy losses become increasingly significant, becoming a major bottleneck limiting the improvement of overall conversion efficiency. To suppress these energy spikes and recover the useful work they contain, 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 structural complexity, number of components, and control logic burden will increase significantly, leading to a significant increase in system implementation difficulty and overall cost.

[0005] This section is intended to provide background or context for the embodiments of this application set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section. Utility Model Content

[0006] This application provides a flyback converter circuit to achieve 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 converter circuit includes: N flyback converter sub-circuits and an input power supply circuit, wherein the input terminal of each flyback converter sub-circuit is connected to the output terminal of the input power supply circuit;

[0008] The i-th flyback converter sub-circuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and M power conversion circuits. 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 in the M power conversion circuits of the i-th flyback converter sub-circuit includes: a first switching transistor, a main transformer, a clamping diode, and a first rectifier diode, where 1≤j≤M and j is a positive integer;

[0010] The first end of the i-th input filter capacitor is 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 converter sub-circuit, and the second end of the i-th input filter capacitor is connected to the first end of all the first switching transistors of the M power conversion circuits in the i-th flyback converter sub-circuit.

[0011] The first terminal of the i-th clamping capacitor is connected to the negative terminal of all clamping diodes of the M power conversion circuits in the i-th flyback converter sub-circuit, and the second terminal of the i-th clamping capacitor is connected to the first terminal of the primary winding of all main transformers of the M power conversion circuits in the i-th flyback converter sub-circuit or to the first terminal of all first switching transistors of the M power conversion circuits in the i-th flyback converter sub-circuit.

[0012] The second terminal of the j-th first switching transistor is connected between the positive terminal of the j-th clamping diode and the second terminal of the primary winding of the j-th main transformer;

[0013] The first terminal of the secondary winding of the j-th main transformer is connected to the positive terminal of the j-th first rectifier diode; the negative terminal of the first rectifier diode in the M power conversion circuits of the i-th flyback converter sub-circuit is connected to the first terminal of at least one output filter capacitor in the i-th output filter circuit; the second terminal of the secondary winding of the main transformer in the M power conversion circuits of the i-th flyback converter sub-circuit is connected to the second terminal of at least one output filter capacitor in the i-th output filter circuit.

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

[0015] This application also provides a flyback converter circuit to achieve 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 converter circuit includes: A flyback converter sub-circuits and an input power supply circuit, wherein the input terminal of each flyback converter sub-circuit is connected to the output terminal of the input power supply circuit;

[0017] The a-th flyback converter sub-circuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and B power conversion circuits. 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 b-th power conversion circuit in the B power conversion circuits of the a-th flyback converter sub-circuit includes: a first switching transistor, a main transformer, a clamping diode, and a first rectifier diode, wherein 2≤b≤B and b is a positive integer;

[0019] The first terminal of the a-th input filter capacitor is connected to the first terminal of the primary winding of all the main transformers of the B power conversion circuits in the a-th flyback converter sub-circuit, and the second terminal of the a-th input filter capacitor is connected to the first connection of all the first switching transistors of the B power conversion circuits in the a-th flyback converter sub-circuit.

[0020] The first terminal of the clamping capacitor is connected to the negative terminal of all clamping diodes of the B power conversion circuits in the flyback converter sub-circuit, and the second terminal of the clamping capacitor is connected to the first terminal of the primary winding of all main transformers of the B power conversion circuits in the flyback converter sub-circuit, or to the first terminal of all first switching transistors of the B power conversion circuits in the flyback converter sub-circuit.

[0021] The second terminal of the b-th first switching transistor is connected between the b-th clamping diode and the second terminal of the primary winding of the b-th main transformer;

[0022] The first terminal of the secondary winding of the b-th main transformer is connected to the positive terminal of the b-th first rectifier diode; the negative terminal of the first rectifier diode in the B power conversion circuits of the a-th flyback converter sub-circuit is connected to the first terminal of at least one output filter capacitor in the a-th output filter circuit; the second terminal of the secondary winding of the main transformer in the B power conversion circuits of the a-th flyback converter sub-circuit is connected to the second terminal of at least one output filter capacitor in the a-th output filter circuit.

[0023] The first terminal of the a-th active snubber circuit is connected between the a-th clamping capacitor and all the clamping diodes of the B power conversion circuits in the a-th flyback converter sub-circuit. The second terminal of the a-th active snubber circuit is connected between the a-th input filter capacitor and the first terminal of the primary winding of all the main transformers of the B power conversion circuits in the a-th flyback converter sub-circuit. The third terminal of the a-th active snubber circuit is connected between the a-th input filter capacitor and the first terminal of all the first switching transistors of the B power conversion circuits in the a-th flyback converter sub-circuit.

[0024] The flyback converter circuit provided in this application, according to the above embodiments, effectively achieves the temporary storage and active recovery of leakage inductance energy of the primary winding of the main transformer by introducing a set of reasonably structured clamping branches and active absorption paths in the flyback converter circuit, significantly improving the energy conversion efficiency of the circuit and the working stability of the switching devices. The clamping branch constructed by the clamping capacitor and clamping diode can absorb the high-frequency peak voltage caused by leakage inductance on the primary winding side when the first switching transistor is turned off, avoiding stress damage to the devices caused by the peak impact and enhancing the reliability of the circuit. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0026] Figure 1 This is a flyback converter circuit with an active absorption circuit in one embodiment of this application;

[0027] Figure 2 This is a flyback converter circuit with an active absorption circuit in another embodiment of this application;

[0028] Figure 3 This is a flyback converter circuit with an active absorption circuit in another embodiment of this application;

[0029] Figure 4 This is a flyback converter circuit with an active absorption circuit in another embodiment of this application;

[0030] Figure 5 This is a DC-DC flyback converter circuit with a shared active absorption circuit in one embodiment of this application;

[0031] Figure 6 This is an AC flyback converter circuit with a shared active absorption circuit in one embodiment of this application;

[0032] Figure 7 This is a flyback converter circuit in one embodiment of this application;

[0033] Figure 8 This is a flyback converter circuit in yet another embodiment of this application;

[0034] Figure 9 This is a flyback converter circuit with an active absorption circuit in another embodiment of this application;

[0035] Figure 10 This is a flyback converter circuit with an active absorption circuit in another embodiment of this application;

[0036] Figure 11 This is a flyback converter circuit with an active absorption circuit in another embodiment of this application;

[0037] Figure 12 This is a DC-DC flyback converter circuit with a shared active absorption circuit in another embodiment of this application;

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

[0039] Figure 14 This is a flyback converter circuit in yet another embodiment of this application;

[0040] Figure 15 This is a flyback converter circuit in yet another embodiment of this application;

[0041] Figure 16 This is a schematic diagram of the timing control of the main power switch in a flyback converter circuit. Detailed Implementation

[0042] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0043] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0044] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0045] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0046] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0047] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] To address the issues of low energy conversion efficiency, high device voltage stress, insufficient leakage inductance energy recovery, and difficulty in circuit integration in multiphase high power density applications under high-frequency operation, this application provides a flyback converter circuit. This flyback converter circuit is driven by multiple AC power supplies, each connected to three flyback converter sub-circuits. Each converter circuit achieves unified absorption and efficient transmission of leakage inductance energy from the primary side of the main transformer through a shared clamping capacitor and a centrally located active absorption circuit. Simultaneously, a multi-parallel output structure for the induced energy from the secondary winding is employed. In some embodiments, this supports parallel connection of 12 output rectifier branches or series connection of 6 output rectifier branches, with unified rectification followed by transmission to the output filter capacitor and load resistor, thereby improving energy feedback efficiency. Compared to traditional discrete clamping and absorption schemes, this structure supports multi-channel interleaved parallel connection and multi-phase input integrated design, effectively reducing overall electromagnetic interference and device redundancy, and improving circuit thermal management and output voltage stability.

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

[0050] The i-th flyback converter sub-circuit includes: input filter capacitor C in The system includes a clamping capacitor C1, an output filter circuit, an active absorption circuit, and M power conversion circuits. The output filter circuit includes at least one output filter capacitor C. O Where 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 j-th power conversion circuit in the M power conversion circuits of the i-th flyback converter sub-circuit includes: a first switching transistor 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 terminal is connected to the first terminal of the primary winding of all the main transformers T1 in the M power conversion circuits of the i-th flyback converter sub-circuit, and the i-th input filter capacitor C in The second terminal is connected to the first terminal of all the first switching transistors Q1 of the M power conversion circuits in the i-th flyback converter sub-circuit.

[0053] The first terminal of the i-th clamping capacitor C1 is connected to the negative terminal of all clamping diodes A1 in the M power conversion circuits of the i-th flyback converter sub-circuit. The second terminal of the i-th clamping capacitor C1 is connected to the first terminal of the primary winding of all main transformers T1 in the M power conversion circuits of the i-th flyback converter sub-circuit, or to the first terminal of all first switching transistors Q1 in the M power conversion circuits of the i-th flyback converter sub-circuit.

[0054] The second terminal of the j-th first switching transistor Q1 is connected between the positive terminal of the j-th clamping diode A1 and the second terminal of the primary winding of the j-th main transformer T1.

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

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

[0057] According to the above embodiments, a three-phase multi-channel interleaved parallel structure achieves improved energy efficiency and modular integration of the flyback converter circuit in high-power applications. Each AC input is connected to a set of flyback converter sub-circuits, and each set of converter circuits contains four power conversion circuits, forming a total of twelve power conversion circuits, significantly improving the circuit's power aggregation capability and output current carrying capacity. Depending on the output topology, each rectifier diode can be connected in parallel with a uniformly configured output filter capacitor, or grouped into two output filter capacitors, thereby constructing a parallel output structure or a parallel-series output structure. This allows for flexible adaptation to different output voltage levels and load current requirements, improving the overall output capability and system compatibility.

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

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

[0060] In some embodiments, such as Figure 1 As shown, when N=3, the input power supply includes: one 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. The two ends of the output side of the i-th rectifier bridge are connected to the i-th input filter capacitor C respectively. in The two ends are connected.

[0061] In this embodiment, the flyback converter circuits are connected to a three-phase AC power supply, with each phase corresponding to a set of flyback converter sub-circuits. The AC power supply (e.g., V) corresponding to the three flyback converter sub-circuits is connected to... ac V bc and V cc They are connected in parallel. Each flyback converter sub-circuit includes four power conversion circuits, for a total of twelve power conversion circuits.

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

[0063] First output filter capacitor C o The first terminal of the first output filter capacitor is connected to the negative terminals of all the first rectifier diodes in the M power conversion circuits of the i-th flyback converter sub-circuit. The second terminal of the first output filter capacitor is connected to the second output terminals of the secondary windings of all the main transformers in the M power conversion circuits of the i-th flyback converter sub-circuit. The first rectifier diodes are rectifier diodes B1 to B... 12 .

[0064] In this embodiment of the application, the first output filter capacitor C o The first terminal is connected to rectifier diodes B1 to B1 respectively. 12 The negative terminal is connected to the first output filter capacitor C. o The second terminal is connected to the main transformer T1 to T 12 The second output terminal of the secondary winding is connected to form a parallel structure of the secondary rectifier output branch, thereby realizing the 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, thus meeting the high-efficiency output requirements of high-power loads.

[0065] In some embodiments, such 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] First output filter capacitor C o Second output filter capacitor C o1 Series connection, first output filter capacitor C o The first terminal is the first input terminal of the i-th output filter circuit, and the second output filter capacitor C o1 The first terminal is the second input terminal of the i-th output filter circuit.

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

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

[0069] In this embodiment, the flyback converter circuits are connected to a three-phase AC power supply, with each phase connected to a set of flyback converter sub-circuits. Each set of flyback converter sub-circuits includes four power conversion circuits, for a total of twelve power conversion circuits across the three phases. Each phase is correspondingly equipped with a main transformer T1 to T2. 12 .

[0070] For example, main transformers T1 to T 12 The output terminals of the secondary windings are respectively connected to the corresponding rectifier diodes B1 to B2. 12 The positive terminal is connected. Among them, the first rectifier diodes B1, B2, B5, B6, B9 and B... 10 Connect the output filter capacitor C oThe first terminal is the output filter capacitor C. o The second end is connected to the main transformers T1, T2, T5, T6, T9 and T1 respectively. 10 The input terminal of the secondary winding. First rectifier diodes B3, B4, B7, B8, B... 11 and B 12 Connect the output filter capacitor C o The second terminal. The second output filter capacitor C. o1 The first end is connected to the main transformers T3, T4, T7, T8, and T1 respectively. 11 and T 12 The input terminal of the secondary winding. Output filter capacitor C. o With output filter capacitor C o1 Further series connection is formed to create a series topology of a parallel rectifier output structure of six power conversion circuits and another parallel rectifier output structure of six circuits. This improves the overall power aggregation capability and current carrying capacity of the unit while ensuring the output voltage level, meeting the actual needs of high power loads for stable and efficient output.

[0071] To improve the energy conversion efficiency and overall reliability of flyback converter circuits under high-frequency operating conditions, and to address the energy loss and device voltage stress caused by leakage inductance energy release during the turn-off of the main power switch in traditional flyback converters, this application provides a flyback converter circuit. By sharing a clamping capacitor across multiple power conversion circuits and combining it with an active absorption circuit composed of the switch, sub-transformer, and rectifier diodes, concentrated absorption and efficient recovery of leakage inductance energy on the primary side of the main transformer are achieved. This structure not only effectively improves the circuit's energy conversion efficiency and reduces the stress burden on power devices caused by voltage spikes, but also reduces the dependence of each parallel power conversion circuit on the capacity of the buffer devices, further enhancing the operational stability of the entire flyback converter circuit under multi-channel interleaved control.

[0072] In some embodiments, such 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 this embodiment, the flyback converter circuit includes: a flyback converter sub-circuit and an input power supply circuit, wherein the input terminal of the flyback converter sub-circuit is connected to the output terminal of the input power supply circuit. The input power supply circuit includes: an AC power supply (AC) and a rectifier bridge (H1).

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

[0075] For example, the first power conversion circuit of the four power conversion circuits in the flyback converter sub-circuit includes: a first switch Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes: a first switch Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes: a first switch Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

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

[0077] The first terminal of clamping capacitor C1 is connected to the negative terminals of all clamping diodes (such as A1, A2, A3, and A4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 is connected to the first terminal of the primary winding of all main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 can also be connected to the drain of all main power switching transistors (such as the first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback converter sub-circuit.

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

[0079] The output terminal of the secondary winding of main transformer T1 is connected to the positive terminal of the first rectifier diode B1. The output terminal of the secondary winding of main transformer T2 is connected to the positive terminal of the first rectifier diode B2. The output terminal of the secondary winding of main transformer T3 is connected to the positive terminal of the first rectifier diode B3. The output terminal of the secondary winding of main transformer T4 is connected to the positive terminal 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 of the flyback converter sub-circuit is connected to the output filter capacitor C in the output filter circuit. o The first terminal is connected, and the load resistor Load is connected in parallel with the output filter capacitor C. o Both ends.

[0081] The input terminals of the secondary windings of the main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit are connected to the output filter capacitor C in the output filter circuit. o The second end is connected.

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

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

[0084] According to the above embodiments, the above structure achieves centralized absorption of leakage inductance energy in the flyback converter circuit through the centralized clamping capacitor and active absorption circuit, effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

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

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

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

[0088] In this embodiment, the flyback converter circuit includes: a flyback converter sub-circuit and an input power supply circuit, wherein the input terminal of the flyback converter sub-circuit is connected to the output terminal of the input power supply circuit. The input power supply includes a DC power supply.

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

[0090] For example, the first power conversion circuit of the four power conversion circuits in the flyback converter sub-circuit includes: a first switch Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes: a first switch Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes: a first switch Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

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

[0092] The first terminal of clamping capacitor C1 is connected to the negative terminals of all clamping diodes (such as A1, A2, A3, and A4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 is connected to the first terminal of the primary winding of all main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 can also be connected to the drain of all main power switching transistors (such as the first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback converter sub-circuit.

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

[0094] The output terminal of the secondary winding of main transformer T1 is connected to the positive terminal of the first rectifier diode B1. The output terminal of the secondary winding of main transformer T2 is connected to the positive terminal of the first rectifier diode B2. The output terminal of the secondary winding of main transformer T3 is connected to the positive terminal of the first rectifier diode B3. The output terminal of the secondary winding of main transformer T4 is connected to the positive terminal 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 of the flyback converter sub-circuit is connected to the output filter capacitor C in the output filter circuit. o The first terminal is connected, and the load resistor Load is connected in parallel with the output filter capacitor C. o Both ends.

[0096] The input terminals of the secondary windings of the main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit are connected to the output filter capacitor C in the output filter circuit. o The second end is connected.

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

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

[0099] According to the above embodiments, the above structure achieves centralized absorption of leakage inductance energy in the flyback converter circuit through the centralized clamping capacitor and active absorption circuit, effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

[0100] To reduce energy loss and voltage spikes caused by leakage inductance in the primary-side resistance of the transformer in flyback converter circuits, and to improve energy recovery efficiency and system reliability, this application provides a flyback converter circuit. This circuit establishes a temporary storage path for leakage inductance energy using a clamping capacitor and a clamping diode, and further introduces an active absorption circuit, including a switching transistor, a sub-transformer, and a rectifier diode. This circuit conducts when the clamping capacitor voltage exceeds a preset threshold, converting and transferring the leakage inductance energy temporarily stored in the clamping branch to the output side for recycling. Compared to traditional circuit structures using passive clamping or energy-loss-type clamping methods, this application, through the coordinated control of the main power switch and the active absorption circuit, effectively releases magnetic flux energy and suppresses leakage inductance spikes during the main transformer's off-state, improving energy utilization efficiency, mitigating the impact of voltage stress on the switching devices, and enhancing the overall conversion efficiency and operational stability of the circuit. It is particularly suitable for flyback topology applications with high power density and stringent EBI control and device protection requirements.

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

[0102] The i-th second switch Q a The first terminal and the i-th input filter capacitor C in The first terminal or the i-th input filter capacitor C in The second terminal is connected to the i-th second switch Q. a The second end and the i-th 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 is connected to 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 is connected to the i-th second rectifier diode D a The positive terminal is connected to the i-th second rectifier diode D. a The negative terminal is connected to at least one output filter capacitor C of the output filter circuit. O The first end is connected to the i-th sub-transformer T. a The second terminal of the secondary winding is connected to at least one output filter capacitor C in the output filter circuit. O The second end is connected.

[0105] In some embodiments, in the i-th flyback converter sub-circuit, when the second switch Q of each of the M power conversion circuits... aWhen turned off, the current in the primary winding of the main transformer of each power conversion circuit is interrupted. A positive voltage is induced in the secondary winding of the main transformer of each power conversion circuit, driving the first rectifier diode of each power conversion circuit to conduct, so that the magnetic flux stored in the main transformer T1 of each power conversion circuit is output to the output filter circuit and the load resistor through the secondary winding of the main transformer T1 of each power conversion circuit.

[0106] The first switching transistor of each power conversion circuit generates leakage inductance energy, which 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 rises and exceeds the preset threshold, the i-th active absorption circuit turns on, transferring 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 rises and exceeds a preset threshold, the i-th second switch Q... a When the circuit is turned on, the leakage inductance energy passes through the i-th second switch 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 positive voltage, driving the i-th second rectifier diode D. a When the circuit is turned on, the leakage inductance energy is transferred to the output filter circuit and the load resistor.

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

[0111] The power conversion circuit includes: clamping diode A1, main power switch Q1 (i.e., the first switch), main transformer T1, and 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 of the main power switch Q1. Both the negative terminal of the DC power supply (DC) and the source of the main power switch Q1 are grounded. The input filter capacitor C... in It is connected in parallel with a DC power supply.

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

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

[0115] The output terminal of the secondary winding of the main transformer T1 is connected to the positive terminal of the first rectifier diode B1. The negative terminal of the first rectifier diode B1 is connected to the output filter capacitor C. o The first connection is between the input terminal of the secondary winding of the main transformer T1 and the output filter capacitor C. o The second end is connected.

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

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

[0118] According to the above embodiments, by introducing a set of reasonably structured clamping branches and active absorption paths into the flyback converter circuit, the temporary storage and active recovery of leakage inductance energy in the primary winding of the main transformer are effectively achieved, significantly improving the energy conversion efficiency of the circuit and the operating stability of the switching devices. The clamping branch constructed by the clamping capacitor and clamping diode can absorb the high-frequency peak voltage caused by leakage inductance on the primary winding side when the main power switch is turned off, avoiding stress damage to the devices caused by the peak impact and enhancing the reliability of the circuit.

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

[0120] Second switching transistor Q a The source is connected to the primary winding of the main transformer T1 and the input filter capacitor C. in Between. The second switch Q a The drain is connected to the sub-transformer T a The output terminal of the primary winding. Sub-transformer T a The input terminal 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 Q a The source can also be connected to the main power switch Q1 and the input filter capacitor C. in between.

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

[0123] According to the above embodiment, by setting an active absorption circuit consisting of a switching transistor, a sub-transformer, and rectifier diodes, 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 turn-off period of the main power switching transistor. Through the above active absorption circuit, not only are leakage inductance spikes suppressed and clamping losses reduced, but the energy utilization efficiency of the flyback converter circuit is also improved. Furthermore, the secondary winding input terminal 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 the stability of the circuit.

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

[0125] In this embodiment, when the main power switch Q1 is turned on, the anode of the clamping diode A1 is pulled to near ground potential, while the cathode of the clamping diode A1 remains at a high potential, resulting in a reverse voltage across the clamping diode A1, meaning the clamping diode A1 is in the off state. At this time, 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 grounded (low potential) through the main power switch Q1, causing current to flow from the DC power supply DC through the primary winding of the main transformer T1 to the ground, and magnetic energy begins to be stored in the core of the main transformer T1.

[0126] Because the polarity of the secondary winding of the main transformer T1 is opposite to that of the primary winding, a reverse voltage is induced in the secondary winding of the main transformer T1 during the conduction of the main power switch Q1. Therefore, the potential at the output terminal (connected to the anode of rectifier diode B1) of the secondary winding of the main transformer T1 is lower than that at the input terminal (connected to the output filter capacitor C). o The voltage (connected to the load resistor Load) causes the rectifier diode B1 to be reverse biased, meaning that the rectifier diode B1 is in the off state. At this time, the required electrical energy is supplied by the output filter capacitor C. o Energy storage is provided in the system.

[0127] In some embodiments, such as Figure 5 and Figure 6 As shown, 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 momentarily interrupted. The magnetic energy stored in the core of the main transformer T1 is converted into an induced voltage, which drives the secondary winding of the main transformer T1 to induce a positive voltage, causing the rectifier diode B1 to conduct. This allows the magnetic flux (i.e., magnetic energy) stored in the main transformer T1 to be output to the output filter capacitor C through the secondary winding of the main transformer T1. o and load resistance.

[0128] Because the turn-off action of the main power switch Q1 causes the leakage inductance current in the primary winding of the main transformer T1 to be unable to be interrupted instantaneously, a high-amplitude spike voltage is induced across the primary winding of the main transformer T1. This spike voltage causes the clamping diode A1 to be in a forward conducting 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 into 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 rises and exceeds the preset threshold value, the active absorption circuit turns on, transferring the leakage inductance energy to the output filter capacitor C. o and load resistance.

[0129] In some embodiments, such as Figure 7 As shown, when the voltage of the clamping capacitor C1 rises and exceeds the preset threshold, the second switch Q...a Controlled conduction: The leakage inductance energy stored in the clamping capacitor C1 is switched on by the second switch Q. a The source and the second switch Q a The drain is transmitted to the sub-transformer T. a The primary winding of the transformer T. a The secondary winding induces a positive voltage due to magnetic coupling, driving the rectifier diode D. a Forward conduction. The leakage inductance energy is supplied by the sub-transformer T. a The secondary winding output is rectified by diode D. a Transmission to output filter capacitor C o The load resistor Load is used to effectively recover the leakage inductance energy of the primary winding of the main transformer T1, thereby improving the overall energy conversion efficiency of the flyback converter circuit.

[0130] According to the above embodiments, a structure combining clamping capacitors and active absorption circuits is adopted to effectively absorb and recover the leakage inductance energy of the primary side of the main transformer during flyback conversion. In traditional flyback converter circuits, the leakage inductance energy generated at the moment the main power switch turns off is usually released into the clamping resistor in the form of a high-amplitude spike voltage, which not only causes energy loss but also introduces large voltage stress on the power devices, affecting the efficiency and reliability of the circuit. This application introduces the leakage inductance energy into the clamping capacitor for temporary storage through clamping diodes. After the voltage of the clamping capacitor rises to a preset threshold, the active absorption circuit is controlled to conduct, driving the sub-transformer to work. The stored leakage inductance energy is then transferred to the secondary winding of the sub-transformer through magnetic coupling and rectified by rectifier diodes before being input to the output filter capacitor and load resistor, thereby realizing energy reuse. The above circuit structure not only improves the energy conversion efficiency of the flyback converter circuit, effectively suppresses the spike voltage of the main power devices, and reduces the power capacity design requirements of the devices in the clamping capacitor and active absorption circuit, but also enhances the stability and overall reliability of the circuit operation.

[0131] To address the issues of low energy conversion efficiency, high device voltage stress, insufficient leakage inductance energy recovery, and difficulty in circuit integration in multiphase high power density applications under high-frequency operation, this application provides a flyback converter circuit. This flyback converter circuit is driven by multiple AC power supplies, each connected to three flyback converter sub-circuits. Each converter circuit achieves unified absorption and efficient transmission of leakage inductance energy from the primary side of the main transformer through a shared clamping capacitor and a centrally located active absorption circuit. Simultaneously, a multi-parallel output structure for the induced energy from the secondary winding is employed. In some embodiments, this supports parallel connection of 12 output rectifier branches or series connection of 6 output rectifier branches, with unified rectification followed by transmission to the output filter capacitor and load resistor, thereby improving energy feedback efficiency. Compared to traditional discrete clamping and absorption schemes, this structure supports multi-channel interleaved parallel connection and multi-phase input integrated design, effectively reducing overall electromagnetic interference and device redundancy, and improving circuit thermal management and output voltage stability.

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

[0133] The a-th flyback converter sub-circuit includes: input filter capacitor C in The circuit includes a clamping capacitor C1, an output filter circuit, an active absorption circuit, and B power conversion circuits. The output filter circuit includes at least one output filter capacitor C. O Where 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 b-th power conversion circuit in the B power conversion circuits of the a-th flyback converter sub-circuit includes: a first switching transistor 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 a-th input filter capacitor C in The first terminal is connected to the first terminal of the primary winding of all the main transformers T1 in the B power conversion circuit of the a-th flyback converter sub-circuit, and the a-th input filter capacitor C in The second terminal is connected to the first terminal of all the first switching transistors Q1 in the B power conversion circuits of the a-th flyback converter sub-circuit.

[0136] The first terminal of the a-th clamping capacitor C1 is connected to the negative terminal of all clamping diodes A1 in the B power conversion circuits of the a-th flyback converter sub-circuit. The second terminal of the a-th clamping capacitor C1 is connected to the first terminal of the primary winding of all main transformers T1 in the B power conversion circuits of the a-th flyback converter sub-circuit, or to the first terminal of all first switching transistors Q1 in the B power conversion circuits of the a-th flyback converter sub-circuit.

[0137] The second terminal of the j-th first switching transistor Q1 is connected between the positive terminal of the j-th clamping diode A1 and the second terminal of the primary winding of the j-th main transformer T1.

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

[0139] The first terminal of the a-th active absorption circuit is connected between the a-th clamping capacitor C1 and all the clamping diodes of the B power conversion circuit in the a-th flyback converter sub-circuit. The second terminal of the a-th active absorption circuit is connected to the a-th input filter capacitor C. in The third terminal of the active snubber circuit is connected between the first terminal of the primary winding of all the main transformers of the B power conversion circuits in the a-th flyback converter sub-circuit and the a-th active snubber circuit. in Between the first terminals of all the first switches of the B power conversion circuits in the a-th flyback converter sub-circuit.

[0140] According to the above embodiments, a three-phase multi-channel interleaved parallel structure achieves improved energy efficiency and modular integration of the flyback converter circuit in high-power applications. Each AC input is connected to a set of flyback converter sub-circuits, and each set of converter circuits contains four power conversion circuits, forming a total of twelve power conversion circuits, significantly improving the circuit's power aggregation capability and output current carrying capacity. Depending on the output topology, each rectifier diode can be connected in parallel with a uniformly configured output filter capacitor, or grouped into two output filter capacitors, thereby constructing a parallel output structure or a parallel-series output structure. This allows for flexible adaptation to different output voltage levels and load current requirements, improving the overall output capability and system compatibility.

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

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

[0143] In some embodiments, such as Figure 9 As shown, when A=3, the input power supply includes: one 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. The two ends of the output side of the a-th rectifier bridge are connected to the a-th input filter capacitor C respectively. in The two ends are connected.

[0144] In this embodiment, the flyback converter circuits are connected to a three-phase AC power supply, with each phase corresponding to a set of flyback converter sub-circuits. The AC power supply (e.g., V) corresponding to the three flyback converter sub-circuits is connected to... ac V bc and V cc They are connected in parallel. Each flyback converter sub-circuit includes four power conversion circuits, for a total of twelve power conversion circuits.

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

[0146] First output filter capacitor C o The first terminal of the capacitor is connected to the negative terminal of all the first rectifier diodes in the B power conversion circuits of the a-th flyback converter sub-circuit. The second terminal of the a-th first output filter capacitor is connected to the second output terminal of the secondary winding of all the main transformers in the B power conversion circuits of the a-th flyback converter sub-circuit. The first rectifier diodes are rectifier diodes B1 to B... 12 .

[0147] In this embodiment of the application, the first output filter capacitor C o The first terminal is connected to rectifier diodes B1 to B1 respectively. 12 The negative terminal is connected to the first output filter capacitor C. o The second terminal is connected to the main transformer T1 to T 12The second output terminal of the secondary winding is connected to form a parallel structure of the secondary rectifier output branch, thereby realizing the 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, thus meeting the high-efficiency output requirements of high-power loads.

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

[0149] First output filter capacitor C o Second output filter capacitor C o1 Series connection, first output filter capacitor C o The first terminal is the first input terminal of the a-th output filter circuit, and the second output filter capacitor C o1 The first terminal is the second input terminal of the a-th output filter circuit.

[0150] In the a-th flyback converter sub-circuit, the negative terminal of at least one first rectifier diode of the B power conversion circuit is connected to the first output filter capacitor C. o At the first terminal, the negative terminal of at least one first rectifier diode of at least B power conversion circuits in the a-th flyback converter sub-circuit is connected to the second output filter capacitor C. o1 The second terminal. The first rectifier diodes are rectifier diodes B1 to B... 12 .

[0151] In this embodiment, the flyback converter circuits are connected to a three-phase AC power supply, with each phase connected to a set of flyback converter sub-circuits. Each set of flyback converter sub-circuits includes four power conversion circuits, for a total of twelve power conversion circuits across the three phases. Each phase is correspondingly equipped with a main transformer T1 to T2. 12 .

[0152] For example, main transformers T1 to T 12 The output terminals of the secondary windings are respectively connected to the corresponding rectifier diodes B1 to B2. 12 The positive terminal is connected. Among them, the first rectifier diodes B1, B2, B5, B6, B9 and B... 10 Connect the output filter capacitor C o The first terminal is the output filter capacitor C. o The second end is connected to the main transformers T1, T2, T5, T6, T9 and T1 respectively. 10 The input terminal of the secondary winding. First rectifier diodes B3, B4, B7, B8, B... 11 and B 12 Connect the output filter capacitor C o The second terminal. The second output filter capacitor C.o1 The first end is connected to the main transformers T3, T4, T7, T8, and T1 respectively. 11 and T 12 The input terminal of the secondary winding. Output filter capacitor C. o With output filter capacitor C o1 Further series connection is formed to create a series topology of a parallel rectifier output structure of six power conversion circuits and another parallel rectifier output structure of six circuits. This improves the overall power aggregation capability and current carrying capacity of the unit while ensuring the output voltage level, meeting the actual needs of high power loads for stable and efficient output.

[0153] To improve the energy conversion efficiency and overall reliability of flyback converter circuits under high-frequency operating conditions, and to address the energy loss and device voltage stress caused by leakage inductance energy release during the turn-off of the main power switch in traditional flyback converters, this application provides a flyback converter circuit. By sharing a clamping capacitor across multiple power conversion circuits and combining it with an active absorption circuit composed of the switch, sub-transformer, and rectifier diodes, concentrated absorption and efficient recovery of leakage inductance energy on the primary side of the main transformer are achieved. This structure not only effectively improves the circuit's energy conversion efficiency and reduces the stress burden on power devices caused by voltage spikes, but also reduces the dependence of each parallel power conversion circuit on the capacity of the buffer devices, further enhancing the operational stability of the entire flyback converter circuit under multi-channel interleaved control.

[0154] In some embodiments, such as Figure 11 As shown, when A=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 a-th input filter capacitor.

[0155] In this embodiment, the flyback converter circuit includes: a flyback converter sub-circuit and an input power supply circuit. The input terminal of the flyback converter sub-circuit is connected to the output terminal of the input power supply circuit. The input power supply 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 is connected to the input filter capacitor C. in in parallel.

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

[0157] For example, the first power conversion circuit of the four power conversion circuits in the flyback converter sub-circuit includes: a first switch Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes: a first switch Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes: a first switch Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

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

[0159] The first terminal of clamping capacitor C1 is connected to the negative terminals of all clamping diodes (such as A1, A2, A3, and A4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 is connected to the first terminal of the primary winding of all main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 can also be connected to the drain of all main power switching transistors (such as the first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback converter sub-circuit.

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

[0161] The output terminal of the secondary winding of main transformer T1 is connected to the positive terminal of the first rectifier diode B1. The output terminal of the secondary winding of main transformer T2 is connected to the positive terminal of the first rectifier diode B2. The output terminal of the secondary winding of main transformer T3 is connected to the positive terminal of the first rectifier diode B3. The output terminal of the secondary winding of main transformer T4 is connected to the positive terminal 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 of the flyback converter sub-circuit is connected to the output filter capacitor C in the output filter circuit. oThe first terminal is connected, and the load resistor Load is connected in parallel with the output filter capacitor C. o Both ends.

[0163] The input terminals of the secondary windings of the main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit are connected to the output filter capacitor C in the output filter circuit. o The second end is connected.

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

[0165] According to the above embodiments, the above structure achieves centralized absorption of leakage inductance energy in the flyback converter circuit through the centralized clamping capacitor and active absorption circuit, effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

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

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

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

[0169] In this embodiment, the flyback converter circuit includes: a flyback converter sub-circuit and an input power supply circuit, wherein the input terminal of the flyback converter sub-circuit is connected to the output terminal of the input power supply circuit. The input power supply includes a DC power supply.

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

[0171] For example, the first power conversion circuit of the four power conversion circuits in the flyback converter sub-circuit includes: a first switch Q1, a main transformer T1, a clamping diode A1, and a first rectifier diode B1. The second power conversion circuit includes: a first switch Q2, a main transformer T2, a clamping diode A2, and a first rectifier diode B2. The third power conversion circuit includes: a first switch Q3, a main transformer T3, a clamping diode A3, and a first rectifier diode B3.

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

[0173] The first terminal of clamping capacitor C1 is connected to the negative terminals of all clamping diodes (such as A1, A2, A3, and A4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 is connected to the first terminal of the primary winding of all main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit. The second terminal of clamping capacitor C1 can also be connected to the drain of all main power switching transistors (such as the first switching transistors Q1, Q2, Q3, and Q4) in the four power conversion circuits of the flyback converter sub-circuit.

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

[0175] The output terminal of the secondary winding of main transformer T1 is connected to the positive terminal of the first rectifier diode B1. The output terminal of the secondary winding of main transformer T2 is connected to the positive terminal of the first rectifier diode B2. The output terminal of the secondary winding of main transformer T3 is connected to the positive terminal of the first rectifier diode B3. The output terminal of the secondary winding of main transformer T4 is connected to the positive terminal 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 of the flyback converter sub-circuit is connected to the output filter capacitor C in the output filter circuit. o The first terminal is connected, and the load resistor Load is connected in parallel with the output filter capacitor C. o Both ends.

[0177] The input terminals of the secondary windings of the main transformers (such as T1, T2, T3, and T4) in the four power conversion circuits of the flyback converter sub-circuit are connected to the output filter capacitor C in the output filter circuit. o The second end is connected.

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

[0179] According to the above embodiments, the above structure achieves centralized absorption of leakage inductance energy in the flyback converter circuit through the centralized clamping capacitor and active absorption circuit, effectively improving the overall energy conversion efficiency and circuit stability of the circuit.

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

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

[0182] 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 of the main power switch Q1. Both the negative terminal of the DC power supply (DC) and the source of the main power switch Q1 are grounded. The input filter capacitor C... in It is connected in parallel with a DC power supply.

[0183] The first terminal of clamping capacitor C1 is connected to the negative terminal of clamping diode A1, and the second terminal of clamping capacitor C1 is connected to the first terminal of the primary winding of main transformer T1.

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

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

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

[0187] The first terminal of the active snubber circuit is connected between clamping capacitor C1 and clamping diode A1. The second terminal of the active snubber circuit is connected between the primary winding of the main transformer T1 and the input filter capacitor C. in Between. 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, this application also provides a flyback converter circuit, such as Figure 15 As shown, the flyback converter circuit includes: a DC power supply DC, and an input filter capacitor C. in Clamping capacitor C1, inductor L k Power conversion circuit, active snubber circuit, output filter capacitor C o and load resistance.

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

[0190] The positive terminal of the DC power supply is connected between the input terminal of the primary winding of the main transformer T1 and the clamping capacitor C1. The negative terminal of the DC power supply is connected to the source of the main power switch Q1, and both the negative terminal of the DC power supply and the source of the main power switch Q1 are grounded. The input filter capacitor C... in It is connected in parallel with a DC power supply. The output terminal 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 terminal of clamping capacitor C1 is connected to the negative terminal of clamping diode A1, and the second terminal of clamping capacitor C1 is connected to the first terminal of the primary winding of main transformer T1. The drain of main power switch Q1 is connected between clamping diode A1 and inductor L. k between.

[0193] The output terminal of the secondary winding of the main transformer T1 is connected to the positive terminal of the first rectifier diode B1. The negative terminal of the first rectifier diode B1 is connected to the output filter capacitor C in the output filter circuit. o The first terminal is connected, and 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 Q. a Inductor L a and rectifier diode D a The second switching transistor Q a With rectifier diode D a One end of the series connection is connected between clamping capacitor C1 and clamping diode A1, and the other end is connected between main power switch Q1 and input filter capacitor C. in between.

[0195] Inductor L a One end is connected to the second switching transistor Q a With rectifier diode D a Between the two ends, the other end is connected to the clamping capacitor C1 and the input filter capacitor C. in between.

[0196] In some embodiments, such as Figure 15 As shown, when the main power switch Q1 is turned off, the inductance L connected to the primary winding of the main transformer T1 is reduced due to the turn-off action of the main power switch Q1. k The leakage inductance current cannot be interrupted instantaneously, inducing a high-amplitude spike voltage across the primary winding of the main transformer T1. This spike voltage causes the clamping diode A1 to be forward-biased, allowing the leakage inductance current to flow through the clamping diode A1 into the clamping capacitor C1. This stores the leakage inductance energy released from the primary winding of the main transformer T1 into the clamping capacitor C1. As the leakage inductance energy gradually accumulates, the voltage across the clamping capacitor C1 continuously rises. When the voltage across the clamping capacitor C1 rises and exceeds a preset threshold, the active absorption circuit conducts, transferring the leakage inductance energy to the input filter capacitor C. in .

[0197] When the voltage of the clamping capacitor C1 rises and exceeds the preset threshold, the second switching transistor Q... a Controlled conduction: The leakage inductance energy stored in the clamping capacitor C1 is switched on by the second switch Q. a The source and the second switch 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 Transmission to input filter capacitor C in This enables effective recovery of leakage inductance energy from the primary winding of the main transformer T1, thereby improving the overall energy conversion efficiency of the flyback converter circuit.

[0198] According to the above embodiments, the clamping branch composed of clamping capacitors and clamping diodes effectively suppresses the high-amplitude voltage spikes caused by leakage inductance energy during the turn-off of the main power switch, thereby improving the stability of circuit operation and the reliability of power devices. The further added active absorption circuit, composed of a switch, inductor, and rectifier diode, enables active regulation and transfer of energy in the clamping branch. It effectively transfers the clamping energy to the primary-side output via electromagnetic coupling, avoiding the direct energy consumption in the clamping resistor in traditional clamping methods and improving the circuit's energy utilization efficiency. Furthermore, by connecting an inductor in series in the primary circuit of the main transformer, the energy transfer path is optimized, transient current spikes are suppressed, and electromagnetic compatibility performance and system efficiency under high-frequency operating conditions are further improved.

[0199] For example, Figure 16 This is a timing control diagram of the main power switch in a flyback converter circuit, applied to the aforementioned flyback converter 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 according to a fixed period. The conduction pulse duration of each main power switch is the same, and the conduction start time of two adjacent main power switches is staggered by 90 electrical degrees, thus forming an equally spaced interleaved control mode.

[0201] For example, the main power switch Q1 is turned on first. Before the main power switch Q1's conduction cycle 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 so on in sequence.

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

[0203] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A flyback converter circuit, characterized in that, include: N flyback converter sub-circuits and an input power supply circuit, wherein the input terminal of each flyback converter sub-circuit is connected to the output terminal of the input power supply circuit; The i-th flyback converter sub-circuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and M power conversion circuits. 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 in the M power conversion circuits of the i-th flyback converter sub-circuit includes: a first switching transistor, a main transformer, a clamping diode, and a first rectifier diode, where 1≤j≤M and j is a positive integer; The first end of the i-th input filter capacitor is 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 converter sub-circuit, and the second end of the i-th input filter capacitor is connected to the first end of all the first switching transistors of the M power conversion circuits in the i-th flyback converter sub-circuit. The first terminal of the i-th clamping capacitor is connected to the negative terminal of all clamping diodes of the M power conversion circuits in the i-th flyback converter sub-circuit, and the second terminal of the i-th clamping capacitor is connected to the first terminal of the primary winding of all main transformers of the M power conversion circuits in the i-th flyback converter sub-circuit or to the first terminal of all first switching transistors of the M power conversion circuits in the i-th flyback converter sub-circuit. The second terminal of the j-th first switching transistor is connected between the positive terminal of the j-th clamping diode and the second terminal of the primary winding of the j-th main transformer; The first terminal of the secondary winding of the j-th main transformer is connected to the positive terminal of the j-th first rectifier diode; the negative terminal of the first rectifier diode in the M power conversion circuits of the i-th flyback converter sub-circuit is connected to the first terminal of at least one output filter capacitor in the i-th output filter circuit; the second terminal of the secondary winding of the main transformer in the M power conversion circuits of the i-th flyback converter sub-circuit is connected to the second terminal of at least one output filter capacitor in the i-th output filter circuit. The first input terminal of the i-th active absorption circuit is connected to the first terminal of the i-th clamping capacitor, the second input terminal of the i-th active absorption circuit is connected to the first terminal or the second terminal of the i-th input filter capacitor, the first output terminal of the i-th active absorption circuit is connected to the first input terminal of the i-th output filter circuit, and the second output terminal of the i-th active absorption circuit is connected to the second input terminal of the i-th output filter circuit.

2. The flyback converter circuit according to claim 1, characterized in that, The i-th active absorption circuit includes: a second switching transistor, a sub-transformer, and a second rectifier diode; The first terminal of the i-th second switch is connected to the first terminal or the second terminal of the i-th input filter capacitor, and the second terminal of the i-th second switch is connected to the first terminal 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 terminal of the i-th second rectifier diode, the negative terminal 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 of the output filter circuit.

3. The flyback converter circuit according to any one of claims 1-2, characterized in that, The input power supply circuit includes a DC power supply.

4. The flyback converter circuit according to any one of claims 1-2, characterized in that, The input power supply circuit includes an AC power supply and a rectifier circuit.

5. The flyback converter circuit according to claim 3, characterized in that, 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.

6. The flyback converter circuit according to claim 4, characterized in that, 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.

7. The flyback converter circuit according to claim 4, characterized in that, When N=3; the input power supply includes: one three-phase AC power supply and three rectifier bridges; the three-phase output terminals of the three-phase AC power supply are respectively connected to the input terminals of the three rectifier bridges, and the two ends of the output side of the i-th rectifier bridge are respectively connected to the two ends of the i-th input filter capacitor.

8. The flyback converter circuit according to any one of claims 1-2, characterized in that, The i-th output filter circuit includes a first output filter capacitor; The first terminal of the first output filter capacitor is connected to the negative terminal of all the first rectifier diodes of the M power conversion circuits in the i-th flyback converter sub-circuit, and the second terminal of the i-th first output filter capacitor is connected to the second output terminal of the secondary winding of all the main transformers of the M power conversion circuits in the i-th flyback converter sub-circuit.

9. The flyback converter circuit according to any one of claims 1-2, 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 terminal of the first output filter capacitor is the first input terminal of the i-th output filter circuit, and the first terminal of the second output filter capacitor is the second input terminal 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 converter sub-circuit is connected to the first terminal 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 converter sub-circuit is connected to the second terminal of the second output filter capacitor.

10. A flyback converter circuit, characterized in that, include: A flyback converter sub-circuit and an input power supply circuit, wherein the input terminal of each flyback converter sub-circuit is connected to the output terminal of the input power supply circuit; The a-th flyback converter sub-circuit includes: an input filter capacitor, a clamping capacitor, an output filter circuit, an active absorption circuit, and B power conversion circuits. 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 b-th power conversion circuit in the B power conversion circuits of the a-th flyback converter sub-circuit includes: a first switching transistor, a main transformer, a clamping diode, and a first rectifier diode, wherein 2≤b≤B and b is a positive integer; The first terminal of the a-th input filter capacitor is connected to the first terminal of the primary winding of all the main transformers of the B power conversion circuits in the a-th flyback converter sub-circuit, and the second terminal of the a-th input filter capacitor is connected to the first terminal of all the first switching transistors of the B power conversion circuits in the a-th flyback converter sub-circuit. The first terminal of the clamping capacitor is connected to the negative terminal of all clamping diodes of the B power conversion circuits in the flyback converter sub-circuit, and the second terminal of the clamping capacitor is connected to the first terminal of the primary winding of all main transformers of the B power conversion circuits in the flyback converter sub-circuit, or to the first terminal of all first switching transistors of the B power conversion circuits in the flyback converter sub-circuit. The second terminal of the b-th first switching transistor is connected between the b-th clamping diode and the second terminal of the primary winding of the b-th main transformer; The first terminal of the secondary winding of the b-th main transformer is connected to the positive terminal of the b-th first rectifier diode; the negative terminal of the first rectifier diode in the B power conversion circuits of the a-th flyback converter sub-circuit is connected to the first terminal of at least one output filter capacitor in the a-th output filter circuit; the second terminal of the secondary winding of the main transformer in the B power conversion circuits of the a-th flyback converter sub-circuit is connected to the second terminal of at least one output filter capacitor in the a-th output filter circuit. The first terminal of the a-th active snubber circuit is connected between the a-th clamping capacitor and all the clamping diodes of the B power conversion circuits in the a-th flyback converter sub-circuit. The second terminal of the a-th active snubber circuit is connected between the a-th input filter capacitor and the first terminal of the primary winding of all the main transformers of the B power conversion circuits in the a-th flyback converter sub-circuit. The third terminal of the a-th active snubber circuit is connected between the a-th input filter capacitor and the first terminal of all the first switching transistors of the B power conversion circuits in the a-th flyback converter sub-circuit.

11. The flyback converter circuit according to claim 10, characterized in that, The input power supply circuit includes a DC power supply.

12. The flyback converter circuit according to claim 10, characterized in that, The input power supply circuit includes an AC power supply and a rectifier circuit.

13. The flyback converter circuit according to claim 11, characterized in that, When N=1, the two ends of the DC power supply are respectively connected to the two ends of the a-th input filter capacitor.

14. The flyback converter circuit according to claim 13, characterized in that, 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 a-th input filter capacitor.

15. The flyback converter circuit according to claim 11, characterized in that, When N=3; the input power supply includes: 1 three-phase AC power supply and 3 rectifier bridges; the three-phase output terminals of the three-phase AC power supply are respectively connected to the input terminals of the 3 rectifier bridges, and the two ends of the output side of the a-th rectifier bridge are respectively connected to the two ends of the i-th input filter capacitor.

16. The flyback converter circuit according to any one of claims 10-15, characterized in that, The a-th output filter circuit includes a first output filter capacitor; The first terminal of the first output filter capacitor is connected to the negative terminal of all the first rectifier diodes of the B power conversion circuits in the a-th flyback converter sub-circuit, and the second terminal of the a-th first output filter capacitor is connected to the second output terminal of the secondary winding of all the main transformers of the B power conversion circuits in the a-th flyback converter sub-circuit.

17. The flyback converter circuit according to any one of claims 10-15, characterized in that, The a-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 terminal of the first output filter capacitor is the first input terminal of the a-th output filter circuit, and the first terminal of the second output filter capacitor is the second input terminal of the a-th output filter circuit. The cathode of at least one first rectifier diode of the B power conversion circuits in the a-th flyback converter sub-circuit is connected to the first terminal of the first output filter capacitor, and the cathode of at least one first rectifier diode of the B power conversion circuits in the a-th flyback converter sub-circuit is connected to the second terminal of the second output filter capacitor.

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