Push-pull resonant converter and driving power source using the same
By using a push-pull resonant converter with a two-stage transformer structure and a shared resonant capacitor, the problems of large transformer size, high voltage, inconsistent parasitic parameters, and severe electromagnetic interference in SiC MOSFET drive power supplies are solved, achieving efficient power isolation and miniaturized design.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SCHNEIDER ELECTRIC (CHINA) CO LTD
- Filing Date
- 2025-05-16
- Publication Date
- 2026-06-23
Smart Images
Figure CN224401407U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of power electronics technology, and more specifically, to a push-pull resonant converter and a drive power supply using the push-pull resonant converter. Background Technology
[0002] SiC MOSFET driver power supplies have high requirements for insulation levels. If high-frequency noise from the power supply generates crosstalk through the transformer, it may interfere with the control circuit and lead to system failure. The trend towards miniaturization has driven driver power supplies to develop towards compactness and high frequency. Based on this, the power supply topology with one drive and multiple outputs has been widely used in the field of SiC MOSFET driver power supplies.
[0003] However, existing multi-output topologies have many shortcomings. On the one hand, the transformers are large, increasing the space occupied by the equipment; on the other hand, the driving MOSFETs need to withstand high voltages, making selection difficult and increasing costs. Furthermore, the output terminals of multi-output transformers exhibit asymmetry, and inconsistencies in parasitic parameters caused by the leads are also significant. Symmetrical design is particularly difficult to achieve in designs such as single-transistor parallel connections. Utility Model Content
[0004] According to an embodiment of the present invention, a push-pull resonant converter is provided, comprising a power supply including a positive terminal VCC and a negative terminal GND; a main transformer including a primary winding and a secondary winding, the primary winding of the main transformer being connected to the positive terminal VCC and the sources of a first switching transistor and a second switching transistor, the secondary winding of the main transformer being connected to a resonant circuit; a first switching transistor and a second switching transistor being connected to the primary winding of the main transformer, the negative terminal GND of the power supply, and a controller; at least one secondary transformer, the secondary winding of each of the at least one secondary transformer being connected to a corresponding load; a resonant circuit including a first resonant capacitor and a second resonant capacitor, the resonant circuit being connected in series between the secondary winding of the main transformer and the primary winding of each of the at least one secondary transformer; and a controller, the first output terminal of the controller being connected to the gate of the first switching transistor, the second output terminal of the controller being connected to the gate of the second switching transistor, and the controller being used to control the on and off of the first and second switching transistors.
[0005] According to an embodiment of the present invention, a first resonant capacitor is connected in series between the first output terminal of the secondary winding of the main transformer and the first input terminal of the primary winding of at least one secondary transformer, and a second resonant capacitor is connected in series between the second output terminal of the secondary winding of the main transformer and the second input terminal of the primary winding of at least one secondary transformer.
[0006] According to an embodiment of the present invention, when the first switch or the second switch is turned on, the first resonant capacitor and the second resonant capacitor are charged, and before the first switch or the second switch is turned off, the first resonant capacitor and the second resonant capacitor are fully charged, wherein the current flowing through the switch is minimal when the first switch or the second switch is turned off.
[0007] According to an embodiment of the present invention, the primary winding of the main transformer includes a first winding and a second winding. The center tap of the primary winding of the main transformer is connected to the positive terminal VCC of the power supply. The first winding is connected to the negative terminal GND of the power supply through a first switching transistor, and the second winding is connected to the negative terminal GND of the power supply through a second switching transistor.
[0008] According to an embodiment of the present invention, the first resonant capacitor and the second resonant capacitor are shared by each of at least one secondary transformer.
[0009] According to an embodiment of the present invention, the controller is a push-pull controller, which is configured to periodically output two complementary control signals through a first output terminal and a second output terminal to control the first switch and the second switch to periodically alternately conduct.
[0010] According to an embodiment of the present invention, the push-pull controller is further configured to insert a dead time between two complementary control signals, during which the first and second switching transistors are turned off.
[0011] According to an embodiment of the present invention, the drain of the first switching transistor and the drain of the second switching transistor are connected to the negative power supply terminal GND.
[0012] According to an embodiment of the present invention, the number of loads is equal to the number of at least one secondary transformer, and the loads correspond one-to-one with each of the at least one secondary transformer.
[0013] According to an embodiment of the present invention, a drive power supply is provided, which is configured to apply a push-pull resonant converter according to an embodiment of the present invention.
[0014] According to embodiments of this invention, the two-stage transformer design in the push-pull resonant converter circuit topology enhances the high- and low-voltage isolation of the power supply, reduces crosstalk coupling between the main circuit and the control circuit, effectively reduces transformer size, and is more suitable for systems with higher requirements for symmetrical PCB layout. Furthermore, connecting a resonant capacitor in series between the main transformer and the secondary transformer effectively reduces voltage stress on the switching transistors, reduces switching losses, and lowers the electromagnetic interference level of the power supply. Attached Figure Description
[0015] The above and other aspects, features, and advantages of specific embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:
[0016] Figure 1 A schematic diagram of the circuit structure of a push-pull resonant converter according to an embodiment of the present invention is shown; and
[0017] Figure 2 A schematic block diagram of the PCB layout of a drive power supply for a push-pull resonant converter according to an embodiment of the present invention is shown. Detailed Implementation
[0018] The present invention will now be described in detail with reference to exemplary embodiments thereof. However, the present invention is not limited to the embodiments described herein, and may be embodied in many different forms. The described embodiments are only intended to make this disclosure thorough and complete, and to fully convey the concept of the present invention to those skilled in the art. Features of the various embodiments described may be combined with or substituted for each other, unless expressly excluded or should be excluded based on the context.
[0019] In embodiments of this novel invention, unless otherwise explicitly stated, "connection" or "connection" does not necessarily mean "direct connection" or "direct contact," but only requires electrical connection. Furthermore, the terms "first," "second," or similar expressions used herein are for descriptive and distinguishing purposes only and do not indicate any priority or order, nor should they be construed as indicating or implying the relative importance of the corresponding components, nor do they represent whether the described parameter values are the same or different.
[0020] In traditional multi-output transformers, which use a single-stage transformer to achieve multiple outputs, inconsistencies in parasitic parameters due to asymmetrical layout can affect system stability and symmetry. Furthermore, the single-stage transformer design results in a large number of winding turns and a large winding height, making the transformer too large to meet the requirements of miniaturization and symmetrical layout.
[0021] Furthermore, if hard-switching technology is used in the design of push-pull resonant converter circuits, it will lead to large switching losses and severe electromagnetic interference, thereby affecting the system performance.
[0022] Figure 1 A schematic diagram of the circuit structure of a push-pull resonant converter 10 according to an embodiment of the present invention is shown.
[0023] like Figure 1As shown, the push-pull resonant converter 10 includes: a power supply, which includes a positive power supply terminal VCC and a negative power supply terminal GND; a main transformer 11, which includes a primary winding and a secondary winding, the primary winding of the main transformer 11 being connected to the positive power supply terminal VCC and the source of a first switching transistor 12 and a second switching transistor 13, and the secondary winding of the main transformer 11 being connected to a resonant circuit; a first switching transistor 12 and a second switching transistor 13, which are connected to the primary winding of the main transformer 11, the negative power supply terminal GND, and a controller 17; and at least one secondary transformer 14, wherein the at least one secondary transformer 14 contains Each of the secondary windings is connected to the corresponding load; a resonant circuit, including a first resonant capacitor 15 and a second resonant capacitor 16, is connected in series between the secondary winding of the main transformer 11 and the primary winding of at least one of the secondary transformers 14; and a controller 17, the first output terminal OUTA of which is connected to the gate of the first switching transistor 12, the second output terminal OUTB of which is connected to the gate of the second switching transistor 13, and the controller 17 is used to control the on and off of the first switching transistor 12 and the second switching transistor 13.
[0024] According to an embodiment of the present invention, the primary winding of the main transformer 11 includes a first winding and a second winding. The center tap of the primary winding of the main transformer 11 is connected to the positive terminal VCC of the power supply. The first winding is connected to the negative terminal GND of the power supply via a first switching transistor 12, and the second winding is connected to the negative terminal GND of the power supply via a second switching transistor 13. The first winding and the second winding are separated by the center tap. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of other connection methods to achieve the above functions, and these implementations all fall within the scope of this disclosure.
[0025] According to an embodiment of the present invention, the source of the first switching transistor 12 and the source of the second switching transistor 13 are connected to the primary winding of the main transformer 11; the drain of the first switching transistor 12 and the drain of the second switching transistor 13 are connected to the negative power supply GND; and the gate of the first switching transistor 12 and the gate of the second switching transistor 13 are connected to the controller 17. In one example, the first switching transistor 12 and the second switching transistor 13 may be power MOSFETs, responsible for controlling the switching of the circuit. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of using other types of switching devices to achieve the above functions, and all such implementations fall within the scope of this disclosure.
[0026] According to an embodiment of the present invention, the primary winding of each of at least one secondary transformer 14 is connected to a first resonant capacitor 15 and a second resonant capacitor 16, respectively, and the secondary winding of each of at least one secondary transformer 14 is connected to a corresponding load. Furthermore, the number of loads is equal to the number of at least one secondary transformer, and each load corresponds one-to-one with each of the at least one secondary transformer. According to an embodiment of the present invention, the number of at least one secondary transformer 14 should be greater than or equal to two, for example, four, thereby achieving four outputs. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of using other numbers of secondary transformers to achieve the above functions, and these implementations all fall within the scope of this disclosure.
[0027] Compared to traditional multi-output transformers, the two-stage transformer design according to this invention offers significant advantages in size control and PCB layout adaptability. The main transformer handles high-voltage isolation and primary-secondary energy transfer; at least one secondary transformer is dedicated to multi-output symmetrical tasks. Through a mirror-symmetric winding design, the geometric parameters of each output circuit are highly consistent. This feature not only enhances the high- and low-voltage isolation of the power system but also significantly reduces crosstalk coupling between the main circuit and the control circuit. Furthermore, the two-stage transformer structure, through physical separation design, avoids space competition between multiple windings of a single-stage transformer. This electrical isolation layout simultaneously solves the complex problem of electromagnetic coupling interference between multiple windings, achieving a dual improvement in electrical performance and space utilization.
[0028] According to an embodiment of the present invention, a first resonant capacitor 15 is connected in series between the first output terminal of the secondary winding of the main transformer 11 and the first input terminal of the primary winding of each of at least one secondary transformer 14, and a second resonant capacitor 16 is connected in series between the second output terminal of the secondary winding of the main transformer 11 and the second input terminal of the primary winding of each of at least one secondary transformer 14. Furthermore, the first and second resonant capacitors are shared by each of the at least one secondary transformer. In one embodiment, the first and second resonant capacitors 15 and 16 are charged when the first switch 12 or the second switch 13 is turned on, and are fully charged before the first switch 12 or the second switch 13 is turned off. Thus, when the first switch 12 or the second switch 13 is turned off, the current flowing through the switch is minimized, achieving zero-current turn-off. It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of using other numbers and types of capacitors to achieve the above functions, and all such implementations fall within the scope of this disclosure.
[0029] According to an embodiment of the present invention, the controller 17 can be a push-pull controller. According to an embodiment of the present invention, the first output terminal OUTA of the controller 17 is connected to the gate of the first switching transistor 12, and the second output terminal OUTB of the controller 17 is connected to the gate of the second switching transistor 13. The on / off states of the switching transistors are controlled through the first output terminal OUTA and the second output terminal OUTB. According to an embodiment of the present invention, the controller 17 is configured to periodically output two complementary control signals through the first output terminal OUTA and the second output terminal OUTB to ensure that the first switching transistor 12 and the second switching transistor 13 are periodically alternately turned on.
[0030] Specifically, when the first output terminal OUTA outputs a high level, the second output terminal OUTB outputs a low level, driving the first switch 12 to turn on and the second switch 13 to turn off; conversely, when the first output terminal OUTA outputs a low level, the second output terminal OUTB outputs a high level, causing the first switch 12 to turn off and the second switch 13 to turn on. Furthermore, to avoid a short circuit caused by simultaneous switching of the switches, the controller 17 incorporates a dead-time control module. At the critical point of the complementary control signal switching, a programmable dead time is automatically inserted. During this period, both the first output terminal OUTA and the second output terminal OUTB output a low level, forcing the first switch 12 and the second switch 13 to be simultaneously off, effectively avoiding the risk of shoot-through short circuits. The specific value of the dead time can be precisely adjusted according to the characteristics of the switches and system requirements to ensure an optimal balance between safety margin and system efficiency.
[0031] In one example, controller 17 employs an open-loop control mode. This mode precisely matches the pre-set switching frequency of controller 17 to the resonant frequency formed by the resonant circuit parameters, ensuring that at the turn-off moment of the first switch 12 or the second switch 13, the current flowing through the switch naturally decays to zero, thus achieving natural zero-crossing turn-off control for the first switch 12 and the second switch 13. This control mechanism eliminates the need for an additional current zero-crossing detection circuit and also eliminates the need to trigger a turn-off signal after detecting a current zero-crossing point.
[0032] According to an embodiment of this invention, the oscillation characteristics generated by the resonant circuit are utilized to precisely control the turn-off time of the switching transistors, so that the current across the first switching transistor 12 or the second switching transistor 13 naturally decays to zero at the moment of turn-off. During this process, although the voltage may change, the switching losses are almost eliminated because the current is zero, thereby significantly reducing the switching losses of the first switching transistor 12 and the second switching transistor 13, while greatly reducing the voltage stress they bear, effectively improving the efficiency and reliability of the system.
[0033] The push-pull resonant converter according to embodiments of this utility model can be applied to the design of various types of drive power supply solutions, such as SiC (silicon carbide), IGBT (insulated gate bipolar transistor), and GaN (gallium nitride). It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of applying the push-pull resonant converter according to embodiments of this utility model to other types of drive power supply solutions to achieve the above-mentioned functions, and all such implementations fall within the scope of this disclosure.
[0034] In one embodiment, the first switch 12 and the second switch 13 may be MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). It should be understood that, based on the teachings given in this disclosure, those skilled in the art can conceive of other types of switches to achieve the above functions, such as IGBTs, and these implementations all fall within the scope of this disclosure.
[0035] Figure 2 A schematic block diagram of a PCB layout 20 for a drive power supply of a push-pull resonant converter according to an embodiment of the present invention is shown.
[0036] According to an embodiment of this utility model, the PCB layout 20 of the drive power supply integrates core functional units such as a power module, a primary transformer, a secondary transformer, a drive chip, a push-pull controller, an overvoltage protection circuit, a temperature control circuit, and connection terminals. The drive power supply PCB layout using the push-pull resonant converter according to this utility model embodiment, through a two-stage transformer structure design and a modular symmetrical layout strategy, not only meets the requirements of a highly symmetrical PCB layout system but also effectively reduces the size of traditional multi-output transformers through a compact planar transformer structure.
[0037] according to Figure 2 This layout design, through the symmetrical distribution and physical separation of functional units, achieves circuit path equalization while avoiding space competition between multiple windings of a single-stage transformer, significantly reducing electromagnetic coupling interference and improving signal transmission consistency and system stability. The two-stage transformer architecture, while ensuring high- and low-voltage isolation performance, achieves a unified approach of PCB layout miniaturization and high symmetry through modular integration, providing a drive solution for precision electronic systems that combines electrical performance and layout advantages. It should be understood that, based on the teachings provided in this disclosure, those skilled in the art can conceive of other types of PCB layouts for drive power supplies to achieve the above functions, and all such implementations fall within the scope of this disclosure.
[0038] It should be noted that, for clarity and simplicity, only the parts related to the embodiments of the present invention are shown in the accompanying drawings. However, those skilled in the art should understand that the devices or apparatus shown in the drawings may include other necessary elements.
[0039] The block diagrams of circuits, devices, apparatuses, equipment, and systems involved in this utility model are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these circuits, devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner that achieves the desired purpose. The quantities involved in this utility model are merely illustrative.
[0040] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.
[0041] Those skilled in the art should understand that the specific embodiments described above are merely examples and not limitations. Various modifications, combinations, partial combinations, and substitutions can be made to the embodiments of this disclosure according to design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents, and thus fall within the scope of the rights to be protected by this disclosure.
Claims
1. A push-pull resonant converter, characterized in that, include: The power supply includes the positive terminal VCC and the negative terminal GND. The main transformer includes a primary winding and a secondary winding. The primary winding of the main transformer is connected to the positive terminal VCC of the power supply and the source of the first switching transistor and the source of the second switching transistor. The secondary winding of the main transformer is connected to a resonant circuit. The first and second switching transistors are connected to the primary winding of the main transformer, the negative terminal GND of the power supply, and the controller. At least one secondary transformer, wherein the secondary winding of each of the at least one secondary transformer is connected to a corresponding load; The resonant circuit includes a first resonant capacitor and a second resonant capacitor, and the resonant circuit is connected in series between the secondary winding of the main transformer and the primary winding of each of the at least one secondary transformer. as well as The controller has a first output terminal connected to the gate of the first switching transistor, a second output terminal connected to the gate of the second switching transistor, and is used to control the on and off states of the first and second switching transistors.
2. The push-pull resonant converter according to claim 1, characterized in that: The first resonant capacitor is connected in series between the first output terminal of the secondary winding of the main transformer and the first input terminal of the primary winding of each of the at least one secondary transformer. The second resonant capacitor is connected in series between the second output terminal of the secondary winding of the main transformer and the second input terminal of the primary winding of each of the at least one secondary transformer.
3. The push-pull resonant converter according to claim 2, characterized in that: When the first switch or the second switch is turned on, the first resonant capacitor and the second resonant capacitor are charged, and Before the first or second switch is turned off, the first and second resonant capacitors are fully charged. Among them, the current flowing through the switch is minimal when either the first or the second switch is turned off.
4. The push-pull resonant converter according to claim 3, characterized in that: The primary winding of the main transformer includes a first winding and a second winding. The center tap of the primary winding of the main transformer is connected to the positive terminal VCC of the power supply. The first winding is connected to the negative terminal GND of the power supply via the first switching transistor, and The second winding is connected to the negative terminal GND of the power supply via the second switching transistor.
5. The push-pull resonant converter according to claim 3, characterized in that: The first resonant capacitor and the second resonant capacitor are shared by each of the at least one secondary transformer.
6. The push-pull resonant converter according to claim 3, characterized in that: The controller is a push-pull controller. The push-pull controller is configured to periodically output two complementary control signals through the first output terminal and the second output terminal to control the first switch and the second switch to periodically alternately conduct.
7. The push-pull resonant converter according to claim 6, characterized in that: The push-pull controller is also configured to insert a dead time between the two complementary control signals, during which the first and second switches are turned off.
8. The push-pull resonant converter according to claim 1, characterized in that: The drains of the first and second switching transistors are connected to the negative power supply terminal GND.
9. The push-pull resonant converter according to claim 1, characterized in that: The number of loads is equal to the number of the at least one secondary transformer, and the loads correspond one-to-one with each of the at least one secondary transformer.
10. A driving power supply, characterized in that: It is configured to use a push-pull resonant converter as described in any one of claims 1-9.