A self-excited push-pull network parallel connection circuit

Abstract

The application belongs to the technical field of electronic circuits, and provides a self-excitation push-pull network parallel connection circuit, which comprises at least two self-excitation push-pull unit branches in parallel with each other; each self-excitation push-pull unit branch is provided with an independent push-pull power tube, a main power transformer and an output rectifier filter unit; the primary side of each self-excitation push-pull unit branch is in parallel with each other, and the secondary side output ends are in parallel with each other. The synchronous coupling windings of each self-excitation push-pull unit branch are in series with each other, forming a common feedback winding as the only driving source. Under the condition of maintaining the synchronous starting, synchronous commutation and synchronous output of the driving current of each branch of the overall parallel circuit, the self-excitation push-pull unit branch can be continuously expanded, the self-excitation push-pull classic topology with an independent feedback winding and the derived circuit thereof can be adapted, and the multi-path parallel architecture can be flexibly built according to the needs, so that the conversion power of the whole machine is improved.

Description

Technical Field

[0001] This application belongs to the field of electronic circuit technology, specifically, it relates to a self-excited push-pull network parallel connection circuit. Background Technology

[0002] Self-excited push-pull converters, with their simple circuit composition, lack of need for independent driver ICs, and ability to start oscillating smoothly with low input voltage, have been widely adopted in DC-DC, DC-AC conversion, backlight driving, and small industrial power supply modules. Industrial applications are centered around the classic Royer and Jensen topologies with independent feedback windings and their improved circuits. With the rapid development of new energy and high-power industrial control equipment, the market demand for high-power expansion of self-excited push-pull converters is increasing year by year. Currently, conventional expansion solutions in the industry are divided into two categories: single-channel device capacity expansion and direct parallel connection of multiple units. Single-channel expansion is limited by the physical limits of power devices and magnetic components, resulting in shortcomings such as excessive temperature rise, decreased reliability, and low power density. Direct parallel connection of multiple converter secondary sides is a common solution for high-power expansion, but the inherent technical defects of this solution are difficult to eliminate.

[0003] In conventional multi-channel parallel architecture, the oscillation processes of each push-pull unit are independent. Component parameter tolerances, environmental temperature changes, and stray wiring parameters can cause inconsistencies in the oscillation frequency and switching phase of each channel. Parallel circuits continuously generate circulating current losses, resulting in low overall efficiency, significant differences in load distribution among channels, frequent branch overload faults, increased output voltage fluctuations, and deterioration of electromagnetic compatibility. Furthermore, as the number of parallel branches increases, the problems of synchronization loss and circulating current deterioration in existing conventional parallel structures will be further amplified, making it impossible to meet the high-power design requirements of large-scale parallel multi-channel connections.

[0004] Therefore, how to develop a parallel topology that can be adapted to multiple channel expansion and synchronously controlled across all branches, while preserving the original core advantages of the self-excited push-pull circuit, has become a technical problem that urgently needs to be solved for the industrial upgrading of high-power self-excited push-pull converters. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a self-excited push-pull network parallel connection circuit.

[0006] In one embodiment, a self-excited push-pull network parallel connection circuit is provided, including at least two self-excited push-pull unit branches connected in parallel; and each self-excited push-pull unit branch is provided with an independent push-pull power transistor, a main power transformer and an output rectifier and filter unit; the primary sides of each self-excited push-pull unit branch are connected in parallel and the secondary output terminals are connected in parallel.

[0007] Furthermore, the main power transformers of each self-excited push-pull unit branch are equipped with synchronous coupling windings with the same number of turns. The synchronous coupling windings of each self-excited push-pull unit branch are connected in series in sequence according to the principle of forming a complete positive feedback oscillation circuit, forming a common feedback winding that serves as the sole driving source for the parallel connection circuit of the self-excited push-pull network. This allows the parallel connection circuit of the self-excited push-pull network to continuously expand the self-excited push-pull unit branch while maintaining synchronous oscillation, synchronous commutation, and synchronous output.

[0008] In one scheme, when there are two self-excited push-pull unit branches, the two self-excited push-pull unit branches are the starting branch and the ending branch, respectively; or when the number of self-excited push-pull unit branches is greater than two, any two of the self-excited push-pull unit branches are selected as the starting branch and the ending branch.

[0009] One end of the synchronous coupling winding of the starting branch serves as the starting part of the common feedback winding and is defined as the starting end, while the other end is the first connection end; one end of the synchronous coupling winding of the ending branch serves as the ending part of the common feedback winding and is defined as the ending end, while the other end is the second connection end.

[0010] Connect the first connection end of the starting branch in series with the second connection end of the ending branch; or start from the first connection end of the starting branch and connect the synchronous coupling windings of the remaining push-pull unit branches in series until the second connection end of the ending branch, forming a complete common feedback winding.

[0011] In one scheme, the common feedback winding does not have a center tap structure. The two ends of the common feedback winding, namely the start end and the end end, are directly used as driving ends, connected to the driving poles of the corresponding push-pull power transistors and the DC bias resistor circuit.

[0012] In one scheme, the common feedback winding has a center tap structure; the center tap structure is connected to the DC bias circuit through the middle common terminal of the common feedback winding, and the two ends of the common feedback winding, namely the start end and the end end, are respectively connected to the driving poles of the corresponding push-pull power transistors.

[0013] In one scheme, the main power transformer windings and corresponding terminals of each push-pull unit branch are located in the same position, and the connection method between each push-pull power transistor and each main power transformer is consistent. The starting end of the starting branch and the ending end of the ending branch are the corresponding or opposite terminals of their respective synchronous coupling windings; the connection method between the starting end and the upper and lower push-pull power transistors of the starting branch, and the connection method between the ending end and the upper and lower push-pull power transistors of the ending branch, all follow the principle of forming a complete positive feedback oscillation circuit.

[0014] Furthermore, when the number of self-excited push-pull unit branches is greater than two, the connection direction of the synchronous coupling winding of the self-excited push-pull unit branches connected between the starting branch and the ending branch, as well as the connection method of the upper and lower push-pull power tubes, all follow the principle of forming a complete positive feedback oscillation circuit.

[0015] Furthermore, the self-excited push-pull unit branch can be a conventional Royer circuit, a simplified feedback Royer circuit, a dual-bias resistor Royer circuit, a quasi-sinusoidal output Royer circuit, or a Jensen circuit.

[0016] Furthermore, each push-pull unit branch uses push-pull power transistors and main power transformers of the same specifications, and the same-name terminal setting position of the main power transformer and the connection method between the push-pull power transistors and the main power transformer are kept consistent to ensure synchronization accuracy and output consistency.

[0017] Furthermore, the synchronous coupling winding of each push-pull unit branch uses 1 to 2 turns to avoid increasing the number of parallel paths, which would cause the total number of turns to be too large and result in the drive reverse voltage exceeding the device's withstand voltage range.

[0018] In one scheme, the method of extending the parallel self-excited push-pull unit branch by the parallel connection circuit of the self-excited push-pull network can also be: The topology network formed by connecting the self-excited push-pull unit branches with a shared common feedback winding in parallel is regarded as a whole reference main branch; based on the reference main branch, several self-excited push-pull unit branches without synchronous coupling windings are connected in parallel as slave branches; the drive poles of the push-pull power transistors of each slave branch are connected in parallel to the drive poles of the push-pull power transistors of the reference main branch, and the unified drive signal of the common feedback winding is reused.

[0019] The beneficial effects of this application are: This application can be universally matched with various self-excited push-pull classic topologies with independent feedback windings and their derivative circuits. Two-way and multi-way parallel architectures can be flexibly built as needed. The output power increases approximately linearly with the increase of parallel branches. After the power is evenly distributed among multiple paths, the pressure and current stress of the single-path transformer and power devices are greatly reduced, reducing device losses and heat generation, which is conducive to product compactness and high-reliability mass production.

[0020] Meanwhile, this application fully inherits the original technical characteristics of self-excited push-pull converters, such as simple circuitry, no need for dedicated driver chips, and smooth low-voltage start-up, forming a reliable, simple, and highly versatile high-power implementation solution; and even in scenarios where the number of parallel branches increases significantly, it can still stably guarantee the drive current of each branch and the conversion power of the whole machine, and has unique advantages in expanding the power capacity of multiple parallel connections. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, 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.

[0022] Figure 1 This is a schematic diagram of a parallel connection circuit of a dual-path Royer network with synchronous in-phase drive in one embodiment of this application; Figure 2 This is a schematic diagram of a parallel connection circuit of a dual-path Royer network with anti-phase synchronous drive in one embodiment of this application; Figure 3 This is a schematic diagram of a dual-path Royer network parallel connection circuit with in-phase synchronous drive without a center tap in one embodiment of this application; Figure 4 This is a schematic diagram of a dual-path Royer network parallel connection circuit with a center-tap-less anti-phase synchronous drive in one embodiment of this application; Figure 5 This is a schematic diagram of a parallel connection circuit of a dual-channel quasi-sinusoidal output type Royer network with synchronous in-phase drive in one embodiment of this application; Figure 6 This is a schematic diagram of a parallel connection circuit of a dual-channel Jensen network with synchronous in-phase drive in one embodiment of this application; Figure 7 This is a schematic diagram of a three-way Royer network parallel connection circuit with in-phase synchronous drive without a center tap in one embodiment of this application; Figure 8 This is a schematic diagram of a three-way Royer network parallel connection circuit with interleaved synchronous drive without a center tap in one embodiment of this application; Figure 9 This is a schematic diagram of a four-way Royer network parallel connection circuit with center tap and in-phase synchronous drive in one embodiment of this application; Figure 10 This is a schematic diagram of a four-way Royer network parallel connection circuit with center tap interleaved synchronous drive in one embodiment of this application; Figure 11 This is a schematic diagram of a parallel connection circuit of three Royer networks with synchronous in-phase drive in one embodiment of this application. Detailed Implementation

[0023] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application. Similarly, the following examples are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0027] In one embodiment, please refer to Figure 1 A self-excited push-pull network parallel connection circuit is provided, including at least two self-excited push-pull unit branches connected in parallel; each self-excited push-pull unit branch is provided with an independent push-pull power transistor, a main power transformer and an output rectifier and filter unit; the primary side of each self-excited push-pull unit branch is connected in parallel and the secondary side output terminals are connected in parallel.

[0028] In this embodiment, synchronous coupling windings with the same number of turns are respectively provided on the main power transformers of the self-excited push-pull unit branches. The synchronous coupling windings of the self-excited push-pull unit branches are connected in series in sequence according to the principle of forming a complete positive feedback oscillation circuit, forming a common feedback winding that serves as the sole driving source of the parallel connection circuit of the self-excited push-pull network. A unique driving signal is generated in a magnetic coupling manner to achieve equal synchronization of the self-excited push-pull unit branches. This allows the parallel connection circuit of the self-excited push-pull network to continuously expand the self-excited push-pull unit branches while maintaining synchronous oscillation, synchronous commutation, and synchronous output.

[0029] In this circuit, the synchronous coupling windings are connected in series sequentially to form a complete positive feedback oscillation loop, creating a common feedback winding that serves as the sole driving source for the parallel connection circuit of the self-excited push-pull network. This common feedback winding, formed by the series connection of each synchronous coupling winding, together with the push-pull power transistors of their respective push-pull unit branches and the primary winding of the main power transformer, generates a common feedback winding. Changes in the collector current of the push-pull power transistors are coupled to the common feedback winding through the main power transformer, and then the signal is sent back to the base of the push-pull power transistors. The returned signal is required to amplify the original current change to achieve positive feedback. In other words, the common feedback winding formed by the series connection of each synchronous coupling winding must meet specific phase conditions, and the polarity of the induced electromotive force at the driving end of the common feedback winding must be strictly matched with the rate of change of the primary current of the main power transformer.

[0030] Furthermore, any two self-excited push-pull unit branches can be arbitrarily selected and defined as the starting branch and the ending branch, respectively. One end of the synchronous coupling winding of the starting branch serves as the starting part of the common feedback winding, defined as the starting end, and the other end is the first connection end. One end of the synchronous coupling winding of the ending branch serves as the ending part of the common feedback winding, defined as the ending end, and the other end is the second connection end. Starting from the first connection end of the synchronous coupling winding of the starting branch, the synchronous coupling windings of the other branches are connected in series sequentially until the second connection end of the ending branch, forming the overall common feedback winding.

[0031] The starting and ending ends of the common feedback winding are not limited to the same-named or different-named ends of the synchronous coupling winding of the starting branch or the synchronous coupling winding of the ending branch. The connection between the common feedback winding and the synchronous coupling windings of other self-excited push-pull unit branches is not limited to the same-named end of one branch connecting to the different-named end of another branch, or the same-named end of one branch connecting to the same-named end of another branch. It is only necessary to ensure that the final common feedback winding can build a stable positive feedback.

[0032] Specifically, the connection between the starting end of the common feedback winding and the drive pole of either the upper or lower push-pull power transistor in the starting branch is determined by the formation of the positive feedback drive voltage and positive feedback cutoff voltage. That is, when the push-pull power transistor connected to the drive pole at the starting end is turned on, the positive voltage coupled to the primary winding of the main power transformer at the starting end provides positive feedback to the turned-on push-pull power transistor, accelerating its conduction; conversely, when it is turned off, the positive feedback accelerates its cutoff. Similarly, the connection between the ending end of the common feedback winding and the drive pole of either the upper or lower push-pull power transistor in the ending branch is also determined by the formation of the positive feedback drive voltage and positive feedback cutoff voltage. Following the same method, the driving poles of the other push-pull power transistor in the starting branch and the other push-pull power transistor in the ending branch, as well as the driving poles of the upper and lower push-pull power transistors in other branches, can all be connected to the starting or ending end of the common feedback winding. The core principle is to construct a positive feedback driving voltage and a positive feedback cutoff voltage, so that all self-excited push-pull unit branches are synchronously driven by the same common feedback winding.

[0033] Therefore, this application is universally compatible with various classic self-excited push-pull topologies with independent feedback windings and their derivative circuits. It can flexibly build two-way and multi-way parallel architectures as needed, and the output power increases approximately linearly with the increase of parallel branches. After the power is evenly distributed among multiple branches, the voltage and current stress of the single-path transformer and power devices is greatly reduced, reducing device losses and heat generation, which is conducive to product compactness and high-reliability mass production. At the same time, this application fully inherits the original technical characteristics of self-excited push-pull converters, such as simple circuits, no need for dedicated driver chips, and smooth low-voltage start-up, forming a reliable, simple, and highly versatile high-power implementation solution. Moreover, even in scenarios with a significant increase in the number of parallel branches, it can still stably guarantee the drive current of each path and the overall conversion power, and has unique advantages in expanding the power capacity of multiple parallel connections.

[0034] In one embodiment, the common feedback winding does not have a center tap structure. The two ends of the common feedback winding, namely the start and end ends, directly serve as drive terminals, connecting to the drive poles of the corresponding push-pull power transistors and the DC bias resistor circuit. This winding design is simple, resulting in lower reverse cutoff voltage stress on the push-pull power transistors.

[0035] In one embodiment, the number of branches in the self-excited push-pull unit is even, and the common feedback winding has a center tap structure. The center tap structure connects the common terminal of the common feedback winding to the DC bias circuit, and the two ends of the common feedback winding, namely the starting end and the ending end, are respectively connected to the driving poles of the corresponding push-pull power transistors. It has good driving symmetry and strong oscillation stability.

[0036] Furthermore, assuming that the main power transformer windings and corresponding terminals of each push-pull unit branch are in the same position, and the connection method between each push-pull power transistor and each main power transformer is consistent, the starting end of the starting branch and the ending end of the ending branch are the corresponding or opposite terminals of their respective synchronous coupling windings. Specifically, the connection method between the starting end and the upper and lower push-pull power transistors of the starting branch, and the connection method between the ending end and the upper and lower push-pull power transistors of the ending branch, both follow the principle of forming a complete positive feedback oscillation circuit.

[0037] Furthermore, this application can conveniently achieve 0° synchronous phase or 180° staggered phase control between the primary sides of each push-pull unit branch, depending on the application scenario requirements. Both 0° synchronous phase and 180° staggered phase control refer to the driving phase of the primary side. For the secondary side and output, the required output voltage ripple phase can be set through the corresponding terminals of the coupling between the secondary winding and the primary winding of the main power transformer.

[0038] Specifically, when there are two self-excited push-pull unit branches, under the premise that the main power transformer windings and the same-name terminals of each self-excited push-pull unit branch are set in the same position, the connection method between each push-pull power tube and each main power transformer is kept the same, and the collector of the upper tube of the push-pull power tube in each self-excited push-pull branch is connected to the same-name terminal of the primary winding of the main power transformer, and the collector of the lower tube of the push-pull power tube is connected to the opposite-name terminal of the primary winding of the main power transformer, if the starting end is the opposite-name terminal and the ending end is the same-name terminal, that is, the connection method of the two sets of synchronous coupling windings is "opposite-name-opposite-name-same-name terminal", then the starting end is connected to the driving pole of the upper tube of the push-pull power tube in the starting branch, the ending end is connected to the driving pole of the lower tube of the push-pull power tube in the ending branch, and the driving pole of the lower tube of the push-pull power tube in the starting branch is connected to the driving pole of the lower tube of the push-pull power tube in the ending branch, and the driving pole of the upper tube of the push-pull power tube in the ending branch is connected to the driving pole of the upper tube of the push-pull power tube in the starting branch. If the starting end is the same-name end and the ending end is the opposite-name end, that is, the connection method of the two sets of synchronous coupling windings is "same-name end-opposite-name end-opposite-name end", then the starting end is connected to the lower drive pole of the push-pull power transistor of the starting branch, the ending end is connected to the upper drive pole of the push-pull power transistor of the ending branch, and the upper drive pole of the push-pull power transistor of the starting branch is connected to the upper drive pole of the push-pull power transistor of the ending branch, and the lower drive pole of the push-pull power transistor of the ending branch is connected to the lower drive pole of the push-pull power transistor of the starting branch. That is, the two ends of the common feedback winding are controlled by the same phase signal at 0°.

[0039] Specifically, when there are two self-excited push-pull unit branches, under the premise that the main power transformer windings and the same-name terminals of each self-excited push-pull unit branch are set in the same position, the connection method between each push-pull power tube and each main power transformer is kept the same, and the collector of the upper tube of the push-pull power tube in each self-excited push-pull branch is connected to the same-name terminal of the primary winding of the main power transformer, and the collector of the lower tube of the push-pull power tube is connected to the opposite-name terminal of the primary winding of the main power transformer, if the starting end is the opposite-name terminal and the ending end is also the opposite-name terminal, that is, the connection method of the two sets of synchronous coupling windings is "opposite-name-name-opposite-name-name terminal", then the starting end is connected to the driving pole of the upper tube of the push-pull power tube in the starting branch, the ending end is connected to the driving pole of the upper tube of the push-pull power tube in the ending branch, and the driving pole of the lower tube of the push-pull power tube in the starting branch is connected to the driving pole of the upper tube of the push-pull power tube in the ending branch, and the driving pole of the lower tube of the push-pull power tube in the ending branch is connected to the driving pole of the upper tube of the push-pull power tube in the starting branch. If the starting end and the ending end are both of the same name, that is, the connection method of the two sets of synchronous coupling windings is "same name end-different name end-different name end-same name end", then the starting end is connected to the lower drive pole of the push-pull power transistor of the starting branch, the ending end is connected to the lower drive pole of the push-pull power transistor of the ending branch, and the upper drive pole of the push-pull power transistor of the starting branch is connected to the lower drive pole of the push-pull power transistor of the ending branch, and the upper drive pole of the push-pull power transistor of the ending branch is connected to the lower drive pole of the push-pull power transistor of the starting branch. That is, the two ends of the common feedback winding are controlled by 180° opposite phase signals.

[0040] Similarly, when the direction of the primary winding terminals of each main power transformer is changed to another direction, the connection method between the starting and ending terminals and the upper and lower tubes of each push-pull power tube is changed accordingly to meet the principle of forming a complete positive feedback oscillation circuit.

[0041] Furthermore, when the number of self-excited push-pull unit branches is greater than two, the connection direction of the synchronous coupling winding of the self-excited push-pull unit branches connected between the starting branch and the ending branch, and the connection method of the driving pole of the upper and lower push-pull power tubes and the driving end of the common feedback winding also follow the principle of connecting to form a complete positive feedback oscillation circuit.

[0042] Specifically, the two ends of the synchronous coupling windings of each push-pull unit branch are defined as first and second access terminals according to the order of connection from the starting end to the ending end. Each first and second access terminal can be a terminal with the same name or a terminal with a different name for each synchronous coupling winding. In particular, the starting end is also the first access terminal of the starting branch, and the ending end is also the second access terminal of the ending branch.

[0043] In this embodiment, given that the main power transformer windings and corresponding terminals of each self-excited push-pull unit branch are positioned in the same way, the connection method between each push-pull power transistor and each main power transformer is the same, and the collector of the upper push-pull power transistor of each self-excited push-pull branch is connected to the corresponding terminal of the primary winding of the main power transformer, and the collector of the lower push-pull power transistor is connected to the opposite terminal of the primary winding of the main power transformer, if the first access terminal of any self-excited push-pull unit branch connected between the starting branch and the ending branch is the corresponding terminal, and the starting terminal is also the corresponding terminal, then the 0° synchronous phase drive control of the corresponding self-excited push-pull unit branch can be achieved by connecting the driving pole of the upper push-pull power transistor of the self-excited push-pull unit branch to the driving terminal of the ending branch of the common feedback winding, and connecting the driving pole of the lower push-pull power transistor of the self-excited push-pull unit branch to the driving terminal of the starting branch of the common feedback winding. If the first input terminal of any self-excited push-pull unit branch connected between the starting branch and the ending branch is a different-named terminal, while the starting terminal is a same-named terminal, then a 180° staggered phase drive control between this part of the self-excited push-pull unit branch and other self-excited push-pull unit branches can be achieved by connecting the upper drive terminal of the push-pull power transistor of this self-excited push-pull unit branch to the starting branch drive terminal of the common feedback winding, and connecting the lower drive terminal of the push-pull power transistor of this self-excited push-pull unit branch to the ending branch drive terminal of the common feedback winding. Here, the drive terminal of the common feedback winding refers to the upper drive terminal or the lower drive terminal of the push-pull power transistor of the starting branch and the ending branch connected at both ends of the common feedback winding.

[0044] Similarly, when the starting end is a different name end, or the direction of the same name end of the primary winding of each main power transformer is changed to another direction, the connection method between the driving pole of the upper and lower tubes of the push-pull power tube of any self-excited push-pull unit branch connected between the starting branch and the ending branch and the driving end of the common feedback winding is changed accordingly to meet the principle of forming a complete positive feedback oscillation circuit.

[0045] When the system is powered on, the startup circuit energizes the DC bias circuit to the two drive terminals of the common feedback winding formed by the series connection of the synchronous coupling windings. This means that the starting and ending terminals simultaneously inject drive current into the drive electrodes of the push-pull power transistors connected to them. Due to manufacturing process variations in the push-pull power transistors, one of them will inevitably conduct first. Assuming the lower push-pull power transistor in the starting branch is connected to the starting terminal of the common feedback winding and conducts first, and assuming its collector is connected to the opposite terminal of the primary winding, the primary winding connected to this lower transistor is energized due to its conduction, with the voltage phase being positive at the same-name terminal and negative at the opposite-name terminal. The starting terminal of the common feedback winding is configured to connect its same-name terminal to the drive electrode of the lower transistor in the starting branch. This coupling of the same-name terminal of the starting terminal with the positive voltage of the same-name terminal of the primary winding creates positive feedback, accelerating the conduction of the lower transistor. Since the push-pull power transistor in the last branch, which is not connected to the end of the common feedback winding, is set to be connected to the starting end, it will synchronously turn on following the drive signal from the starting end, and synchronously excite the primary winding connected to its collector. Correspondingly, the other drive end of the common feedback winding, i.e., the end of the synchronous coupling winding in the last branch, also follows the principle of a positive feedback oscillation circuit, with a negative voltage phase to keep the corresponding push-pull power transistor in the off-state. When the main power transformer in the starting branch becomes magnetically saturated, the phase of the primary winding of the main power transformer in the starting branch flips, and the phase of the primary winding coupled to the starting end flips, changing from "positive" to "negative." The push-pull power transistor connected to the starting end changes from on to off; correspondingly, the phase of the other drive end of the common feedback winding, i.e., the end end, flips from "negative" to "positive," and the push-pull power transistor connected to the end end changes from off to on. This completes one oscillation cycle. Since the common feedback winding is formed by connecting the synchronous coupling windings of each branch in series, the synchronous coupling windings of each branch all participate in magnetic coupling. That is, the synchronous coupling windings of each branch are coupled to the primary current changes of the main power transformer of their respective self-excited push-pull unit branch, and finally connected in series to jointly establish a stable self-excited oscillation, generating drive signals of the same frequency that act on the push-pull power transistors of their respective self-excited push-pull unit branches. Since each push-pull power transistor is driven uniformly by the common feedback winding, if the self-excited push-pull unit branches are driven in the same direction and phase, the push-pull power transistors of the self-excited push-pull unit branches will be turned on or off simultaneously, and the main power transformers of each branch will be synchronously excited and demagnetized, and the secondary side will be synchronously rectified and output. If the self-excited push-pull unit branches are driven by staggered reverse phases, the switching timing of the corresponding two self-excited push-pull unit branches will be staggered by 180°. When one self-excited push-pull unit branch is turned on, the other self-excited push-pull unit branch will be turned off synchronously, and vice versa. The excitation and demagnetization processes of the corresponding two main power transformers will be staggered, and the ripple current of the secondary rectified output will cancel each other out.

[0046] Each synchronous coupling winding with a different name or the synchronous coupling winding with the same name can only be connected once to form a connection point.

[0047] Furthermore, this application does not depend on a specific circuit topology. The self-excited push-pull unit branch can be a conventional Royer circuit, a simplified feedback Royer circuit, a dual-bias resistor Royer circuit, a quasi-sinusoidal output Royer circuit, or a Jensen circuit. As long as the self-excited push-pull unit branch has an independent feedback synchronous coupling winding, stable, efficient, and non-circulating current multi-path parallel power expansion can be achieved based on this application.

[0048] Furthermore, as a preferred embodiment of this application, each self-excited push-pull unit branch uses push-pull power transistors of the same specification, ensuring that the key parameters such as switching characteristics, amplification factor, and withstand voltage of the push-pull power transistors in each branch are highly consistent, reducing synchronization deviation at the device level. Each self-excited push-pull unit branch uses a main power transformer with completely identical model specifications and winding parameters, ensuring complete matching of the electromagnetic characteristics of the primary-side excitation and secondary-side output of each branch, further improving synchronization stability. The connection method between the push-pull power transistors and the main power transformer in each self-excited push-pull unit branch, as well as the setting of the same-name terminals of the primary and secondary windings, are consistent, providing a foundation for precise control of the drive phase of each branch.

[0049] Furthermore, the number of turns (nf) of the synchronous coupling winding in each push-pull unit branch is 1 to 2 turns. This range of turns helps ensure that the reverse driving voltage generated by the synchronous coupling winding for the push-pull power transistor meets the derating requirements of the push-pull power transistor voltage stress, while also ensuring the driving capability when multiple circuits are connected in parallel. Since the total number of turns of the common feedback winding in this application's connection method is equal to the number of turns (nf) of the synchronous coupling winding... N (where N is the total number of parallel branches) The more parallel branches there are, the larger the total number of turns in the feedback winding. Therefore, nf should not be set too large to avoid the total number of turns causing the drive reverse voltage to exceed the device's withstand voltage range.

[0050] In one embodiment, for high-stability scenarios requiring multiple high-power parallel connections, the method of extending the parallel self-excited push-pull unit branches via the parallel connection circuit of the self-excited push-pull network can also be: The topology network formed by parallel connection of the individual push-pull unit branches sharing a common feedback winding is considered as a whole as the reference main branch. Several self-excited push-pull unit branches without synchronous coupling windings are then connected in parallel to the reference main branch as slave branches. The drive terminals of the push-pull power transistors in each slave branch are connected in parallel to the drive terminals of the push-pull power transistors in the reference main branch, reusing the unified drive signal of the common feedback winding. That is, while leveraging the high synchronization and stability of the series connection of the synchronous coupling windings of the individual push-pull unit branches, and combining the easy scalability and low cost advantages of the reference main branch coordinating with the slave branches, the quasi-main branch, through the oscillation circuit constructed by the series connection of two windings, has higher stability and stronger driving capability, providing a unified drive signal for all slave branches. The push-pull power transistors of the slave branches share the exact same drive signal as their corresponding push-pull power transistors in the reference main branch, and the turn-on and turn-off timings are entirely determined by the oscillation circuit of the reference main branch, achieving synchronous operation.

[0051] In one embodiment, as a preferred implementation, please refer to... Figure 1 This paper provides a parallel connection circuit for a dual-path Royer network with synchronous in-phase drive. This embodiment consists of two self-excited push-pull unit branches, branch 1 and branch 2, with completely identical structures. Both branches adopt a standard Royer topology and share the same input power supply Vin. The primary sides are connected in parallel to the power supply bus, and the secondary sides, after rectification and filtering, converge to the same output terminal to achieve power superposition.

[0052] In this embodiment, the synchronous coupling winding Nf1 of the main power transformer T1 in branch 1 and the synchronous coupling winding Nf2 of the main power transformer T2 in branch 2 are connected in series to construct a unique common feedback drive loop. Specifically, the opposite-named terminal of Nf1 is connected to the same-named terminal of Nf2, so that the two synchronous coupling windings are connected in series to form a common feedback winding with a center tap. The center tap is connected to the bias circuit node C1, and the two ends are respectively used as the unified drive signal output terminals of the overall circuit. This common feedback winding, together with the push-pull power transistors of the two branches and the primary winding of the main power transformer, constitutes a complete positive feedback oscillation loop, providing a unique drive signal source for the entire parallel circuit. In branch 1, the base of TR1 is the drive terminal b1, the base of TR2 is the drive terminal b2, and in branch 2, the base of TR3 is the drive terminal b3, the base of TR4 is the drive terminal b4; the same-named terminal of Nf1 is connected to b2, and the opposite-named terminal of Nf2 is connected to b3.

[0053] In this embodiment, the driving terminals of the two push-pull power transistors are connected in parallel with the same phase: b1 and b3 are directly connected, and b2 and b4 are directly connected. The connection method of the two bias circuits and the setting of the same-name terminals of the primary and secondary windings of the main power transformer are kept completely consistent to ensure the uniformity of the driving phase, excitation direction and output phase.

[0054] When the system is powered on, the common feedback winding formed by the two synchronously coupled windings connected in series establishes a stable self-excited oscillation by coupling the changes in the primary current of the two main power transformers, generating drive signals with the same frequency and phase. Since all push-pull power transistors are driven by the same set of common feedback windings, the push-pull power transistors of branch 1 and branch 2 will turn on and off simultaneously, and the two main power transformers will be synchronously energized and demagnetized, with synchronous rectification output on the secondary side. Thus, the two synchronously coupled windings are mutually coupled and mutually constrained, forcibly unifying the oscillation frequency and phase of the two paths. This fundamentally eliminates the timing deviation and circulating current problems caused by the discreteness of components in traditional independent parallel schemes. The power distribution between the two paths is more balanced, resulting in higher overall efficiency, lower output ripple, and stronger stability.

[0055] In one embodiment, as a preferred implementation, please refer to... Figure 2 This paper provides a parallel connection circuit for a dual-path Royer network with anti-phase synchronous drive. This embodiment consists of two self-excited push-pull unit branches, branch 1 and branch 2, with completely identical structures. It adopts a standard Royer topology, with the primary side connected in parallel to the power supply bus and the secondary side connected in parallel for output. The two synchronous coupling windings Nf1 and Nf2 are also connected in series to construct a common feedback drive loop.

[0056] In this embodiment, the series polarity of each synchronous coupling winding and the connection method of the drive terminal are both designed to be opposite. Specifically, the opposite-named terminal of synchronous coupling winding Nf1 in branch 1 is connected to the opposite-named terminal of synchronous coupling winding Nf2 in branch 2, so that the drive signals output from the two ends of the common feedback winding formed by the series connection of the two synchronous coupling windings are out of phase. The center tap of this common feedback winding is also connected to the bias circuit node C1, providing a unique drive signal source for the entire system. In branch 1, the base of TR1 is the drive terminal b1, the base of TR2 is the drive terminal b2, and in branch 2, the base of TR3 is the drive terminal b3, the base of TR4 is the drive terminal b4; the same-named terminal of Nf1 is connected to b2, and the same-named terminal of Nf2 is connected to b4.

[0057] Regarding the connection method of the driving end, this embodiment adopts a cross-parallel connection method: the base driving end b1 of TR1 in branch 1 is directly connected to the base driving end b4 of TR4 in branch 2, and the base driving end b2 of TR2 in branch 1 is directly connected to the base driving end b3 of TR3 in branch 2, so that the turn-on and turn-off timings of the two push-pull power transistors are staggered by 180°.

[0058] After the system is powered on, the common feedback winding formed by the series connection of two synchronously coupled windings establishes a stable self-excited oscillation by coupling the current changes of the two main power transformers. The generated drive signals are applied to the push-pull power transistors of the two branches respectively. Due to the cross-connection of the drive signals, when the upper transistor of branch 1 is turned on, the lower transistor of branch 2 is turned on synchronously; when the lower transistor of branch 1 is turned on, the upper transistor of branch 2 is turned on synchronously. The excitation and demagnetization processes of the two main power transformers are interleaved. This 180° phase difference operating mode makes the ripple current of the rectified output of the two secondary sides cancel each other out, significantly reducing the overall output voltage ripple, and effectively improving the electromagnetic interference characteristics of the circuit. It is very suitable for high-power power supply applications with strict requirements for output ripple and EMI.

[0059] In one embodiment, as a preferred implementation, please refer to... Figure 3 This paper provides a parallel connection circuit for a dual-path Royer network with synchronous in-phase drive without a center tap. This embodiment consists of two identical self-excited push-pull unit branches, branch 1 and branch 2. Both branches employ a simplified feedback Royer topology with independent bias resistors. They share the same input power supply Vin, with the primary sides connected in parallel to the power supply bus. After rectification and filtering on the secondary sides, the power is converged to the same output terminal to achieve power superposition.

[0060] In this embodiment, the bias circuit adopts an independent bias design. Branch 1 and Branch 2 are respectively equipped with bias resistors R1 and R2, each independently providing DC bias current to the push-pull power transistors. Regarding the feedback drive loop, the synchronous coupling winding Nf1 of the main power transformer T1 in Branch 1 and the synchronous coupling winding Nf2 of the main power transformer T2 in Branch 2 are connected in series to construct a unique common feedback drive loop. Specifically, the opposite-named terminal of Nf1 is connected to the same-named terminal of Nf2. After the two feedback windings are connected in series, they directly form a complete common feedback winding, without a center tap. The two ends of this common feedback winding serve as the unified drive signal output terminals for the entire system, simultaneously providing drive signals to the push-pull power transistors of both branches. In Branch 1, the base of TR1 is the drive terminal b1, and the base of TR2 is the drive terminal b2. In Branch 2, the base of TR3 is the drive terminal b3, and the base of TR4 is the drive terminal b4. The same-named terminal of Nf1 is connected to b2, and the opposite-named terminal of Nf2 is connected to b3.

[0061] In this embodiment, the driving terminals of the two push-pull power transistors are connected in parallel with the same phase: b1 and b3 are directly connected, and b2 and b4 are directly connected. The same-name terminals of the primary and secondary windings of the two main power transformers are set in complete consistency to ensure the uniformity of the driving phase, excitation direction and output phase.

[0062] When the system powers on, the common feedback winding formed by the series connection of two synchronously coupled windings establishes a stable self-excited oscillation by coupling the changes in the primary current of the two main power transformers, generating drive signals of the same frequency and phase. Since all push-pull power transistors are driven by the same set of common feedback windings, the push-pull power transistors of branch 1 and branch 2 will turn on and off simultaneously, and the two main power transformers will be synchronously energized and demagnetized, with synchronous rectification output on the secondary side. The independent bias design makes the DC bias conditions of the two branches more stable, and the series connection of the synchronously coupled windings forces the unification of the oscillation frequency and phase of the two paths, eliminating the timing deviation and circulating current problems caused by the discreteness of components in the traditional independent parallel scheme. The power distribution of the two paths is more balanced, resulting in higher overall efficiency, lower output ripple, and stronger stability.

[0063] In one embodiment, as a preferred implementation, please refer to... Figure 4 This paper provides a dual-path Royer network parallel connection circuit with a center-tap-less anti-phase synchronous drive. This embodiment consists of two self-excited push-pull unit branches, branch 1 and branch 2, with completely identical structures. It adopts a simplified feedback Royer topology with independent bias resistors. The primary side is connected in parallel, and the secondary side can be output in parallel. The two synchronous coupling windings Nf1 and Nf2 are also connected in series to construct a common feedback drive loop.

[0064] In this embodiment, the series polarity of the synchronous coupling windings and the connection method of the drive terminals are both designed to be opposite. Specifically, the opposite-named terminals of the synchronous coupling winding Nf1 in branch 1 and the opposite-named terminals of the synchronous coupling winding Nf2 in branch 2 are connected. The common feedback winding formed by the series connection of the two synchronous coupling windings has drive signals with opposite phases at its two ends. The two ends of this common feedback winding also serve as the unified drive signal output terminals of the entire parallel circuit, providing drive signals for the push-pull power transistors of the two branches. In branch 1, the base of TR1 is the drive terminal b1, and the base of TR2 is the drive terminal b2. In branch 2, the base of TR3 is the drive terminal b3, and the base of TR4 is the drive terminal b4. The same-named terminal of Nf1 is connected to b2, and the same-named terminal of Nf2 is connected to b4.

[0065] Regarding the connection method of the driving end, this embodiment adopts a cross-parallel connection method: the base driving end b1 of TR1 in branch 1 is directly connected to the base driving end b4 of TR4 in branch 2, and the base driving end b2 of TR2 in branch 1 is directly connected to the base driving end b3 of TR3 in branch 2, so that the turn-on and turn-off timings of the two push-pull power transistors are staggered by 180°.

[0066] After the system is powered on, the common feedback winding formed by the series connection of two synchronously coupled windings establishes a stable self-excited oscillation by coupling the current changes of the two main power transformers. The generated drive signals are applied to the push-pull power transistors of the two branches respectively. Due to the cross-connection of the drive signals, when the upper transistor of branch 1 is turned on, the lower transistor of branch 2 is turned on synchronously; when the lower transistor of branch 1 is turned on, the upper transistor of branch 2 is turned on synchronously. The excitation and demagnetization processes of the two main power transformers are interleaved.

[0067] In one embodiment, as a preferred implementation, please refer to... Figure 5 This paper provides a parallel connection circuit for a dual-channel quasi-sinusoidal output Royer network with synchronous in-phase drive. This embodiment consists of two identical self-excited push-pull unit branches, branch 1 and branch 2. Both branches adopt a quasi-sinusoidal output Royer topology and share the same input power supply Vin. The primary sides are connected in parallel to the power supply bus, and the secondary sides, after rectification and filtering, converge to the same output terminal to achieve power superposition.

[0068] In this embodiment, branch 1 has an inductor L1 connected in series in its power supply circuit, and a capacitor CL1 connected in parallel between push-pull power transistors TR1 and TR2; branch 2 has an inductor L2 connected in series in its power supply circuit, and a capacitor CL2 connected in parallel between push-pull power transistors TR3 and TR4, so that the circuit can operate in a quasi-resonant state and the output waveform is smoother. The synchronous coupling winding Nf1 of the main power transformer T1 of branch 1 and the synchronous coupling winding Nf2 of the main power transformer T2 of branch 2 are connected in series to construct a unique common feedback drive circuit. Specifically, the opposite-named terminal of Nf1 is connected to the same-named terminal of Nf2, so that the two synchronous coupling windings are connected in series to form a common feedback winding with a center tap. The center tap is connected to the bias circuit node C1, and the two ends are respectively used as the unified drive signal output terminals of the overall circuit. This common feedback winding, together with the push-pull power transistors of the two branches and the primary winding of the main power transformer, constitutes a complete positive feedback oscillation circuit, providing a unique drive signal source for the entire parallel circuit. In branch 1, the base of TR1 is the driving terminal b1, the base of TR2 is the driving terminal b2, and in branch 2, the base of TR3 is the driving terminal b3, the base of TR4 is the driving terminal b4; the same-name terminal of Nf1 is connected to b2, and the different-name terminal of Nf2 is connected to b3.

[0069] In this embodiment, the driving terminals of the two push-pull power transistors are connected in parallel with the same phase: b1 and b3 are directly connected, and b2 and b4 are directly connected. The connection method of the two bias circuits and the setting of the same-name terminals of the primary and secondary windings of the main power transformer are kept completely consistent to ensure the uniformity of the driving phase, excitation direction and output phase.

[0070] When the system is powered on, the common feedback winding formed by the two synchronously coupled windings connected in series establishes a stable self-excited oscillation by coupling the changes in the primary current of the two main power transformers, generating drive signals of the same frequency and phase. Since all push-pull power transistors are driven by the same set of common feedback windings, the push-pull power transistors of branch 1 and branch 2 will be turned on and off simultaneously, and the two main power transformers will be synchronously energized and demagnetized, with synchronous rectification output on the secondary side.

[0071] In one embodiment, as a preferred implementation, please refer to... Figure 6 This paper provides a parallel connection circuit for a dual-channel Jensen network with synchronous in-phase drive. This embodiment consists of two identical self-excited push-pull unit branches, branch 1 and branch 2. Both branches adopt the classic self-oscillating Jensen topology and share the same input power supply Vin. The primary sides are connected in parallel to the power supply bus, and the secondary sides, after rectification and filtering, converge to the same output terminal to achieve power superposition.

[0072] In this embodiment, branch 1 drives the saturated transformer Ta, which has a drive winding Na and a feedback winding Nf1. Branch 2 has a drive winding Nb and a feedback winding Nf2. The feedback winding Nf1 of the drive saturated transformer Ta of branch 1 and the feedback winding Nf2 of the drive saturated transformer Tb of branch 2 are connected in series to construct a unique common feedback drive loop. Specifically, the opposite-named terminal of Nf1 is connected to the same-named terminal of Nf2, so that the two feedback windings Nf1 and Nf2 are connected in series to form a common feedback winding with a center tap. The center tap is connected to the bias circuit node C1, and the two ends serve as the unified drive signal output terminals of the entire circuit. The common feedback winding, together with the push-pull power transistors of the two branches and the primary winding of the main power transformer, constitutes a complete positive feedback oscillation loop, providing a unique drive signal source for the entire parallel circuit. In branch 1, the base of TR1 is the driving terminal b1, the base of TR2 is the driving terminal b2, and in branch 2, the base of TR3 is the driving terminal b3, the base of TR4 is the driving terminal b4; the same-name terminal of Nf1 is connected to b1, and the different-name terminal of Nf2 is connected to b4.

[0073] In this embodiment, the driving terminals of the two push-pull power transistors are connected in parallel with the same phase: b1 and b3 are directly connected, and b2 and b4 are directly connected. The connection method of the two bias circuits and the setting of the same-name terminals of the primary and secondary windings of the main power transformer are kept completely consistent to ensure the uniformity of the driving phase, excitation direction and output phase.

[0074] When the system is powered on, the common feedback winding formed by the feedback windings Nf1 and Nf2 of the two drive saturation transformers Ta and Tb, connected in series, establishes a stable self-excited oscillation by coupling the changes in the primary current of the two main power transformers, generating drive signals of the same frequency and phase. Since all push-pull power transistors are driven by the same set of common feedback windings, the push-pull power transistors of branch 1 and branch 2 will be turned on and off simultaneously. The two main power transformers are synchronously energized and demagnetized, and the secondary side is synchronously rectified and output. Furthermore, thanks to the Jensen topology's feature of separating the drive function from the power transmission, the system oscillation frequency is less affected by the input voltage, load current, and ambient temperature, resulting in better operational stability.

[0075] In one embodiment, as a preferred implementation, please refer to... Figure 7 This paper provides a three-way Royer network parallel connection circuit with in-phase synchronous drive and no center tap. This embodiment consists of three self-excited push-pull unit branches (branch 1, branch 2, and branch 3) with identical structures. All three branches adopt a simplified feedback Royer topology and share the same input power supply Vin. The primary sides are connected in parallel to the power supply bus, and the secondary sides, after rectification and filtering, converge to the same output terminal to achieve power superposition.

[0076] In this embodiment, each of the three branches has synchronous coupling windings Nf1, Nf2, and Nf3, which are connected in series to form a unique common feedback drive loop. Specifically, the opposite-named terminal of Nf1 is connected to the same-named terminal of Nf3, and then the opposite-named terminal of Nf3 is connected to the same-named terminal of Nf2, so that the three synchronous coupling windings are connected in series to form a complete common feedback winding. No center tap is required. By setting bias resistors R1 and R2 respectively, two independent bias circuits are formed. The two ends of this common feedback winding are connected to the nodes of the two bias circuits, and simultaneously provide drive signals for the push-pull power transistors of the three branches. In branch 1, the base of TR1 is the drive terminal b1, and the base of TR2 is the drive terminal b2. In branch 2, the base of TR3 is the drive terminal b3, and the base of TR4 is the drive terminal b4. In branch 3, the base of TR5 is the drive terminal b5, and the base of TR6 is the drive terminal b6. The same-name terminal of Nf1 is connected to b2, and the opposite-name terminal of Nf2 is connected to b3. To achieve synchronous operation of the three circuits in phase, the drive terminals adopt a parallel connection in phase, that is, b1, b3, and b5 are connected, and b2, b4, and b6 are connected. The same-name terminals of the three bias circuits and the primary and secondary sides of the main power transformer are set in the same way to ensure that the drive phase, excitation direction, and output phase are completely unified.

[0077] When the system powers on, the common feedback winding formed by the three synchronously coupled windings connected in series establishes a stable self-excited oscillation by coupling the changes in the primary current of the three main power transformers, generating drive signals of the same frequency and phase. Since all push-pull power transistors are driven by the same set of common feedback windings, the push-pull power transistors of the three branches will conduct and cut off simultaneously, and the three main power transformers will be synchronously energized and demagnetized, with synchronous rectification output on the secondary side. The independent bias design makes the DC bias conditions of the three branches more stable, and the series connection of the synchronously coupled windings forces the unification of the oscillation frequency and phase of the three paths, fundamentally eliminating the timing deviation and circulating current problems caused by the discreteness of components in the traditional three-path independent parallel scheme. The power distribution of the three paths is more balanced, the overall working efficiency is higher, the output ripple is smaller, and the stability is stronger. It can stably realize the superimposed output of the three paths, meeting the application requirements of higher power levels.

[0078] In one embodiment, as a preferred implementation, please refer to... Figure 8 This paper provides a three-way Royer network parallel connection circuit with non-center tapped interleaved synchronous drive. This embodiment consists of three self-excited push-pull unit branches (branch 1, branch 2, and branch 3) with identical structures. A simplified feedback Royer topology is adopted, with parallel connection on the primary side and parallel output on the secondary side. The three synchronous coupling windings Nf1, Nf2, and Nf3 are also connected in series to construct a common feedback drive loop.

[0079] In this embodiment, the series polarity of the synchronous coupling windings is staggered. The opposite-named terminals of Nf1 and Nf3 can be connected, and the same-named terminal of Nf3 can be connected to the opposite-named terminal of Nf2. This allows the common feedback winding formed by the three synchronous coupling windings to output a phase-interleaved drive signal. A center tap is no longer required. By setting bias resistors R1 and R2 respectively, two independent bias circuits are formed. The two ends of the common feedback winding are connected to the nodes of the two bias circuits, simultaneously providing drive signals for the push-pull power transistors of the three branches. In branch 1, the base of TR1 is the drive terminal b1, and the base of TR2 is the drive terminal b2. In branch 2, the base of TR3 is the drive terminal b3, and the base of TR4 is the drive terminal b4. In branch 3, the base of TR5 is the drive terminal b5, and the base of TR6 is the drive terminal b6. The same-named terminal of Nf1 is connected to b2, and the same-named terminal of Nf2 is connected to b4.

[0080] In terms of drive-end connection, branch 1 and branch 2 adopt an interleaved parallel connection: b1 is connected to b4, and b2 is connected to b3, so that the turn-on and turn-off sequences of these two push-pull power transistors are interleaved by 180°; branch 3, according to the connection method of the synchronous coupling winding, uses b6 to connect to b1 and b5 to connect to b2, so that the three branches form an interleaved working mode of two anti-phase and one following. The three bias circuits and the same-name terminals of the primary and secondary sides of the main power transformer are all kept consistent to ensure that the drive phase, excitation direction and output phase are interleaved as required by the design.

[0081] After the system is powered on, the common feedback winding formed by the three synchronously coupled windings connected in series establishes a stable self-excited oscillation by coupling the current changes of the three main power transformers. The generated drive signal is applied to the push-pull power transistors of the three branches through cross-connection. Due to the cross-connection of the drive signals, the switching timing of branch 1 and branch 2 is staggered by 180°, while branch 3 follows the phase of branch 1. The excitation and demagnetization processes of the three main power transformers are interleaved, and the ripple current of the secondary rectified output cancels each other out, significantly reducing the overall output voltage ripple and effectively improving the electromagnetic interference characteristics of the circuit.

[0082] In one embodiment, as a preferred implementation, please refer to... Figure 9 This paper provides a four-way parallel connection circuit of Royer network with center tap and synchronous drive. This embodiment consists of four self-excited push-pull unit branches with completely identical structures: branch 1, branch 2, branch 3, and branch 4. All four branches adopt the standard Royer topology and share the same input power supply Vin. The primary side is connected in parallel to the power supply bus, and the secondary side is rectified and filtered to converge to the same output terminal to achieve power superposition.

[0083] In this embodiment, each of the four branches has a synchronous coupling winding Nf1, Nf2, Nf3, and Nf4, which are connected in series to form a unique common feedback drive loop. Specifically, the opposite-named terminal of Nf1 is connected to the same-named terminal of Nf3, the opposite-named terminal of Nf3 is connected to the same-named terminal of Nf4, and the opposite-named terminal of Nf4 is connected to the same-named terminal of Nf2, so that the four synchronous coupling windings are connected in series to form a complete common feedback winding. Its center tap is connected to the bias circuit node C1, and its two ends serve as the unified drive signal output terminals of the system. This common feedback winding, together with the push-pull power transistors of the four branches and the primary winding of the main power transformer, constitutes a complete positive feedback oscillation loop, providing a unique drive signal source for the entire parallel circuit. In branch 1, the base of TR1 is the drive terminal b1, and the base of TR2 is the drive terminal b2. In branch 2, the base of TR3 is the drive terminal b3, and the base of TR4 is the drive terminal b4. In branch 3, the base of TR5 is the drive terminal b5, and the base of TR6 is the drive terminal b6. In branch 4, the base of TR7 is the drive terminal b7, and the base of TR8 is the drive terminal b8. The same-name terminal of Nf1 is connected to b2, and the opposite-name terminal of Nf2 is connected to b3. To achieve synchronous operation of the four circuits in phase, the drive terminals adopt a parallel connection in phase: b1, b3, b5, and b7 are directly connected, and b2, b4, b6, and b8 are directly connected. The same-name terminals of the four bias circuits and the primary and secondary windings of the main power transformer are all set in complete consistency to ensure the uniformity of the drive phase, excitation direction, and output phase.

[0084] When the system powers on, the common feedback winding formed by the four synchronously coupled windings connected in series establishes a stable self-excited oscillation by coupling the changes in the primary current of the four main power transformers, generating drive signals of the same frequency and phase. Since all push-pull power transistors are driven by the same common feedback winding, the push-pull transistors of the four branches will simultaneously turn on and off, and the four main power transformers will be synchronously energized and demagnetized, with synchronous rectification output on the secondary side. The series connection of the synchronously coupled windings forces a unified oscillation frequency and phase of the four paths, fundamentally eliminating the timing deviation and circulating current problems caused by the discreteness of components in the traditional four-path independent parallel scheme. The power distribution of the four paths is more balanced, the overall operating efficiency is higher, the output ripple is smaller, and the stability is stronger. It can stably achieve the superimposed output of the four paths, meeting the application requirements of higher power levels.

[0085] In one embodiment, as a preferred implementation, please refer to... Figure 10 This invention provides a four-way Royer network parallel connection circuit with center tapped interleaved synchronous drive. This embodiment consists of four identical self-excited push-pull unit branches (branch 1, branch 2, branch 3, and branch 4), employing a standard Royer topology. The primary side is connected in parallel, and the secondary side can be connected in parallel for output. The four synchronous coupling windings Nf1, Nf2, Nf3, and Nf4 are connected in series to construct a common feedback drive loop.

[0086] In this embodiment, the series polarity of the synchronous coupling windings and the connection method of the drive terminals are both staggered. Specifically, the opposite-named terminal of Nf1 is connected to the opposite-named terminal of Nf3, the same-named terminal of Nf3 is connected to the same-named terminal of Nf4, and the opposite-named terminal of Nf4 is then connected to the opposite-named terminal of Nf2, so that the common feedback winding formed by the four synchronous coupling windings in series outputs a drive signal with staggered phases. In branch 1, the base of TR1 is the drive terminal b1, and the base of TR2 is the drive terminal b2; in branch 2, the base of TR3 is the drive terminal b3, and the base of TR4 is the drive terminal b4; in branch 3, the base of TR5 is the drive terminal b5, and the base of TR6 is the drive terminal b6; in branch 4, the base of TR7 is the drive terminal b7, and the base of TR8 is the drive terminal b8; the same-named terminal of Nf1 is connected to b2, and the same-named terminal of Nf2 is connected to b4.

[0087] In terms of drive-end connection, a cross-parallel connection is adopted: the upper drive terminal b1 of branch 1 is connected to the lower drive terminal b4 of branch 2, and the lower drive terminal b2 of branch 1 is connected to the upper drive terminal b3 of branch 2; the upper drive terminal b5 of branch 3 is connected to the lower drive terminal b8 of branch 4, and the lower drive terminal b6 of branch 3 is connected to the upper drive terminal b7 of branch 4, forming a working mode of "branch 1 and branch 4 are in phase, branch 2 and branch 3 are in phase, and the two groups are staggered by 180°". The four bias circuits and the primary and secondary terminals of the main power transformer are all set in the same position to ensure that the drive phase, excitation direction and output phase are staggered as required by the design.

[0088] After the system is powered on, the common feedback winding formed by the four synchronously coupled windings connected in series establishes a stable self-excited oscillation by coupling the current changes of the four main power transformers. The generated drive signal is applied to the push-pull power transistors of the four branches through cross-connection. Due to the cross-connection of the drive signal, when branch 1 and branch 4 are synchronously turned on, branch 2 and branch 3 are synchronously turned off; and vice versa. The switching sequence of the two sets of branches is staggered by 180°. The excitation and demagnetization processes of the four main power transformers alternate, and the ripple current of the secondary rectified output cancels each other out, significantly reducing the overall output voltage ripple and effectively improving the electromagnetic interference characteristics of the circuit.

[0089] In one embodiment, as a preferred implementation, please refer to... Figure 11 This paper provides a parallel connection circuit for three Royer networks with synchronous in-phase drive. This embodiment consists of two main branches and one slave branch. Both main branches adopt the standard Royer topology, while the slave branch adopts a Royer topology that eliminates its independent feedback drive path. All three branches share the same input power supply Vin. The primary sides are connected in parallel to the power supply bus, and the secondary sides, after rectification and filtering, converge to the same output terminal to achieve power superposition.

[0090] In this embodiment, main branch 1 and main branch 2 have complete push-pull power transistors, main power transformers, and synchronous coupling windings. Branch 3 retains push-pull power transistors TR5 and TR6 and main power transformer T3, completely eliminating its own synchronous coupling winding, and only serves as a power output unit receiving unified drive signal control. The synchronous coupling winding Nf1 of main branch 1 and the synchronous coupling winding Nf2 of main branch 2 are connected in series, that is, the opposite-named terminal of Nf1 is connected to the same-named terminal of Nf2, forming a common feedback winding with a center tap, constructing a unique reference oscillation circuit as the drive signal source for the entire circuit. The base of TR1 in main branch 1 is the drive terminal b1, and the base of TR2 is the drive terminal b2; the base of TR3 in main branch 2 is the drive terminal b3, and the base of TR4 is the drive terminal b4; the base of TR5 in branch 3 is the drive terminal b5, and the base of TR6 is the drive terminal b6; the same-named terminal of Nf1 is connected to b2, and the opposite-named terminal of Nf2 is connected to b3. To achieve synchronous operation of the three circuits in phase, the drive end adopts a parallel connection method, as shown in connection method 1: connect b1, b3, and b5 directly, and connect b2, b4, and b6 directly. The bias circuits of the three circuits and the primary and secondary terminals of the main power transformer are all set in the same way to ensure that the drive phase, excitation direction and output phase are completely unified.

[0091] When the system is powered on, the common feedback winding formed by the synchronous coupling windings of the two main branches, connected in series, jointly establishes a stable self-excited oscillation. The generated drive signal simultaneously acts on the push-pull power transistors of the three branches. Since all push-pull power transistors are driven by the same set of common feedback windings, the switching timing, excitation, and demagnetization processes of the three branches are completely synchronized. Although branch 3 does not have an independent synchronous coupling winding, it can still operate stably following the main branches. This structure retains the high synchronization and stability of the two main branches in the series drive scheme, and achieves power superposition of the three branches by adding a slave branch. It eliminates the timing deviation and circulating current problems of the traditional three-way independent parallel scheme, resulting in balanced power distribution, higher overall efficiency, and lower output ripple, which can stably meet the application requirements of higher power levels.

[0092] The above are merely optional embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A self-excited push-pull network parallel connection circuit, characterized in that, It includes at least two self-excited push-pull unit branches connected in parallel; and each of the self-excited push-pull unit branches is equipped with an independent push-pull power transistor, a main power transformer and an output rectifier and filter unit; the primary side of each of the self-excited push-pull unit branches is connected in parallel and the secondary side output terminals are connected in parallel. Furthermore, the main power transformers of each self-excited push-pull unit branch are respectively provided with synchronous coupling windings with the same number of turns. The synchronous coupling windings of each self-excited push-pull unit branch are connected in series in sequence according to the principle of connecting to form a complete positive feedback oscillation circuit, forming a common feedback winding that serves as the sole driving source of the parallel connection circuit of the self-excited push-pull network. This allows the parallel connection circuit of the self-excited push-pull network to continuously expand the self-excited push-pull unit branch while maintaining synchronous oscillation, synchronous commutation, and synchronous output.

2. The self-excited push-pull network parallel connection circuit according to claim 1, characterized in that, When there are two branches in the self-excited push-pull unit, the two self-excited push-pull unit branches are the starting branch and the ending branch, respectively; or when the number of self-excited push-pull unit branches is greater than two, any two self-excited push-pull unit branches can be selected as the starting branch and the ending branch. One end of the synchronous coupling winding of the starting branch serves as the starting part of the common feedback winding and is defined as the starting end, while the other end is the first connection end; one end of the synchronous coupling winding of the ending branch serves as the ending part of the common feedback winding and is defined as the ending end, while the other end is the second connection end. Connect the first connection end of the starting branch in series with the second connection end of the ending branch; or start from the first connection end of the starting branch and connect the synchronous coupling windings of the remaining push-pull unit branches in series until the second connection end of the ending branch, forming a complete common feedback winding.

3. The self-excited push-pull network parallel connection circuit according to claim 2, characterized in that, The common feedback winding does not have a center tap structure. The two ends of the common feedback winding, namely the starting end and the ending end, are directly used as driving ends, connected to the driving poles of the corresponding push-pull power transistors, and to the DC bias resistor circuit.

4. The self-excited push-pull network parallel connection circuit according to claim 2, characterized in that, The common feedback winding has a center tap structure; the center tap structure is connected to the DC bias circuit through the middle common terminal of the common feedback winding, and the two ends of the common feedback winding, namely the starting end and the ending end, are respectively connected to the driving poles of the corresponding push-pull power transistors.

5. The self-excited push-pull network parallel connection circuit according to claim 2, characterized in that, The main power transformer windings and corresponding terminals of each self-excited push-pull unit branch are in the same position, and the connection method between each push-pull power tube and each main power transformer is consistent. The starting end of the starting branch and the ending end of the ending branch are the same-named or different-named ends of their respective synchronous coupling windings; wherein, the connection method between the starting end and the upper and lower push-pull power transistors of the starting branch, and the connection method between the ending end and the upper and lower push-pull power transistors of the ending branch, both follow the principle of connecting to form a complete positive feedback oscillation circuit.

6. The self-excited push-pull network parallel connection circuit according to claim 5, characterized in that, When the number of self-excited push-pull unit branches is greater than two, the synchronous coupling winding connection direction and the upper and lower tube connection method of each self-excited push-pull unit branch connected between the starting branch and the ending branch all follow the principle of forming a complete positive feedback oscillation circuit.

7. The self-excited push-pull network parallel connection circuit according to claim 1, characterized in that, The self-excited push-pull unit branch can be a conventional Royer circuit, a simplified feedback Royer circuit, a dual-bias resistor Royer circuit, a quasi-sinusoidal output Royer circuit, or a Jensen circuit.

8. The self-excited push-pull network parallel connection circuit according to any one of claims 1 to 7, characterized in that, Each of the self-excited push-pull unit branches uses the same specifications of push-pull power transistors and main power transformers, and the same-name terminal of the main power transformer and the connection method between the push-pull power transistors and the main power transformer are kept consistent.

9. The self-excited push-pull network parallel connection circuit according to any one of claims 1 to 7, characterized in that, The synchronous coupling winding of each self-excited push-pull unit branch has 1 to 2 turns.

10. The self-excited push-pull network parallel connection circuit according to claim 8, characterized in that, The method by which the parallel connection circuit of the self-excited push-pull network expands the parallel self-excited push-pull unit branch can also be: The topology network formed by connecting the respective excitation push-pull unit branches that share the common feedback winding in parallel is regarded as a whole reference main branch; based on the reference main branch, several self-excitation push-pull unit branches without synchronous coupling windings are connected in parallel as slave branches. The drive terminals of the push-pull power transistors of each branch are connected in parallel to the drive terminals of the push-pull power transistors of the reference main branch, and the unified drive signal of the common feedback winding is reused.

Images