Voltage conversion circuit

Abstract

The application provides a voltage conversion circuit, which comprises a first input end, a second input end, a first output end and a second output end, wherein the second input end is electrically connected to the second output end; a first full-bridge sub-circuit comprising a first left bridge arm and a first right bridge arm; a first resonance branch comprising a first capacitor and a first primary winding connected in series; a second resonance branch comprising a second capacitor and a second primary winding connected in series; a first rectification branch comprising a first secondary winding and a third switch connected in series; a second rectification branch comprising a second secondary winding and a sixth switch connected in series; a second full-bridge sub-circuit comprising a second left bridge arm, a second right bridge arm and a third secondary winding; and an output capacitor. The voltage conversion circuit provided herein is suitable for large integer voltage ratio requirements, and can improve efficiency while reducing cost.

Description

Technical Field

[0001] This application relates to the field of power electronic conversion technology, and more specifically, to a voltage conversion circuit. Background Technology

[0002] To achieve a fixed integer voltage ratio, existing voltage conversion circuits typically require adjusting the turns ratio of the transformer's primary and secondary windings to achieve voltage regulation matching. To achieve a large integer voltage ratio, the number of winding turns must be significantly increased. This not only increases winding length, copper losses, and core losses, but also raises transformer size and winding height, leading to increased power supply volume and material processing costs. To address these issues, existing technologies have proposed improvements such as adding auxiliary windings and resonant inductors. However, these solutions introduce additional power devices or magnetic components, further increasing losses and enhancing circuit structure and control complexity, making it difficult to simultaneously meet the design requirements of low cost and high energy efficiency.

[0003] It is evident that existing methods for achieving large integer voltage ratios by adjusting the transformer turns ratio have significant shortcomings. Therefore, there is an urgent need for a solution that can achieve large integer voltage ratios without using transformers with large turns ratios. Summary of the Invention

[0004] The purpose of this application is to solve the problems of traditional voltage conversion circuits relying on increasing the number of winding turns to achieve large integer voltage ratios, resulting in high losses, large size, and low efficiency, and to provide a voltage conversion circuit that can achieve large integer voltage ratios without increasing the transformer turns ratio.

[0005] According to one aspect of this application, a voltage conversion circuit is provided, the circuit comprising: a first input terminal, a second input terminal, a first output terminal, and a second output terminal, wherein the second input terminal is electrically coupled to the second output terminal; a first full-bridge sub-circuit, comprising a first left bridge arm and a first right bridge arm, wherein the first left bridge arm comprises a first switch and a second switch connected in series; the first right bridge arm comprises a fourth switch and a fifth switch connected in series; and wherein a first terminal of the first switch is electrically coupled to a first terminal of the fourth switch and the first input terminal; a first resonant branch, comprising a first capacitor and a first primary winding connected in series, wherein... The first resonant branch has its first terminal electrically coupled to the second terminal of the first switch and the first terminal of the second switch, and its second terminal electrically coupled to the second terminal of the fifth switch; the second resonant branch includes a second capacitor and a second primary winding connected in series, wherein the first terminal of the second resonant branch is electrically coupled to the second terminal of the fourth switch and the first terminal of the fifth switch, and its second terminal is electrically coupled to the second terminal of the second switch; the first rectifier branch includes a first secondary winding and a third switch connected in series, wherein the second terminal of the second resonant branch is electrically coupled to the first secondary winding. The second end of the first secondary winding and the first end of the third switch; a second rectifier branch, including a second secondary winding and a sixth switch connected in series, wherein the second end of the first resonant branch is electrically coupled to the first end of the second secondary winding and the first end of the sixth switch, and wherein the first end of the first rectifier branch is electrically coupled to the first end of the second rectifier branch; a second full-bridge sub-circuit, including a second left bridge arm, a second right bridge arm and a third secondary winding, wherein the second left bridge arm includes a seventh switch and an eighth switch connected in series; the second right bridge arm includes a ninth switch and a tenth switch connected in series; the first end of the third secondary winding... The third secondary winding is electrically coupled to the second terminal of the seventh switch and the first terminal of the eighth switch; the second terminal of the third secondary winding is electrically coupled to the second terminal of the ninth switch and the first terminal of the tenth switch; and an output capacitor, the first terminal of which is electrically coupled to the first terminal of the first rectifier branch, the first terminal of the second rectifier branch, the first terminal of the seventh switch, the first terminal of the ninth switch, and the first output terminal; the second terminal of which is electrically coupled to the second terminal of the first rectifier branch, the second terminal of the second rectifier branch, the second terminal of the eighth switch, the second terminal of the tenth switch, and the second output terminal.

[0006] According to an embodiment of this application, a first terminal of the first capacitor is electrically coupled to a second terminal of the first switch, a second terminal of the first capacitor is electrically coupled to a first terminal of the first primary winding, a first terminal of the second capacitor is electrically coupled to a second terminal of the fourth switch, and a second terminal of the second capacitor is electrically coupled to a second terminal of the second primary winding; the second terminal of the first primary winding is electrically coupled to a first terminal of the second secondary winding, a second terminal of the fifth switch, and a first terminal of the sixth switch; the first terminal of the second primary winding is electrically coupled to a second terminal of the first secondary winding, a second terminal of the second switch, and a third switch. The first terminal; the first terminal of the first secondary winding is electrically coupled to the second terminal of the second secondary winding, the first terminal of the seventh switch, the first terminal of the ninth switch and the first terminal of the output capacitor, the second terminal of the first secondary winding is electrically coupled to the second terminal of the second switch and the first terminal of the third switch, the first terminal of the second secondary winding is electrically coupled to the second terminal of the fifth switch and the first terminal of the sixth switch; and wherein, the first terminal of the first primary winding, the first terminal of the second primary winding, the first terminal of the first secondary winding, the first terminal of the second secondary winding and the first terminal of the third secondary winding are terminals of the same name.

[0007] According to an embodiment of this application, when the voltage conversion circuit operates in the first operating mode, the first capacitor operates in a charging state and the second capacitor operates in a discharging state.

[0008] According to an embodiment of this application, when the voltage conversion circuit operates in the second operating mode, the second capacitor operates in a charging state, and the first capacitor operates in a discharging state.

[0009] According to an embodiment of this application, the first switch, the third switch, the fifth switch, the seventh switch, and the tenth switch are simultaneously turned on or off, and the second switch, the fourth switch, the sixth switch, the eighth switch, and the ninth switch are simultaneously turned on or off.

[0010] According to an embodiment of this application, the number of turns of the first primary winding is the same as the number of turns of the second primary winding, denoted as N1; and the number of turns of the first secondary winding, the number of turns of the second secondary winding, and the number of turns of the third secondary winding are the same, denoted as N2, where N1 and N2 are positive integers.

[0011] According to an embodiment of this application, the voltage between the first input terminal and the second input terminal is the input voltage Vin, and the voltage between the first output terminal and the second output terminal is the output voltage Vo. The relationship between the input voltage Vin and the output voltage Vo is as follows:

[0012] Vin / Vo = 2N + 4, where N = N1 / N2.

[0013] According to an embodiment of this application, the voltage conversion circuit further includes an output load electrically coupled to both ends of the output capacitor.

[0014] According to an embodiment of this application, the voltage conversion circuit further includes an input capacitor electrically coupled between the first input terminal and the second input terminal.

[0015] According to an embodiment of this application, the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, the eighth switch, the ninth switch, and the tenth switch are MOSFETs.

[0016] According to another aspect of this application, a voltage conversion circuit is provided, the circuit comprising: a first input terminal, a second input terminal, a first output terminal, and a second output terminal, wherein the second input terminal is electrically coupled to the second output terminal; a first full-bridge sub-circuit, comprising a first left bridge arm and a first right bridge arm, wherein the first left bridge arm comprises a first switch and a second switch connected in series; the first right bridge arm comprises a fourth switch and a fifth switch connected in series; and wherein a first terminal of the first switch is electrically coupled to a first terminal of the fourth switch and the first input terminal; a resonant branch, comprising a first capacitor and a first primary winding connected in series, wherein a first terminal of the resonant branch is electrically coupled to a second terminal of the first switch and a first terminal of the second switch, and a second terminal of the resonant branch is electrically coupled to a second terminal of the fourth switch and a first terminal of the fifth switch; a first rectifier branch, comprising a first secondary winding and a third switch connected in series, wherein a second terminal of the second switch is electrically coupled to a second terminal of the first secondary winding and a first terminal of the third switch; a second rectifier branch, comprising a second secondary winding and a sixth primary winding connected in series. A switch, wherein the first terminal of the first rectifier branch is electrically coupled to the first terminal of the second rectifier branch, and the second terminal of the fifth switch is electrically coupled to the first terminal of the second secondary winding and the first terminal of the sixth switch; a second full-bridge sub-circuit, including a second left bridge arm, a second right bridge arm and a third secondary winding, wherein the second left bridge arm includes a seventh switch and an eighth switch connected in series; the second right bridge arm includes a ninth switch and a tenth switch connected in series; the first terminal of the third secondary winding is electrically coupled to the second terminal of the seventh switch and the first terminal of the eighth switch, and the second terminal of the third secondary winding is electrically coupled to the second terminal of the ninth switch and the first terminal of the tenth switch; and an output capacitor, the first terminal of which is electrically coupled to the first terminal of the first rectifier branch, the first terminal of the second rectifier branch, the first terminal of the seventh switch, the first terminal of the ninth switch and the first output terminal; the second terminal of which is electrically coupled to the second terminal of the first rectifier branch, the second terminal of the second rectifier branch, the second terminal of the eighth switch, the second terminal of the tenth switch and the second output terminal.

[0017] According to an embodiment of this application, the first terminal of the first capacitor is electrically coupled to the second terminal of the first switch, and the second terminal of the first capacitor is electrically coupled to the first terminal of the first primary winding; the second terminal of the first primary winding is electrically coupled to the second terminal of the fourth switch and the first terminal of the fifth switch; the first terminal of the first secondary winding is electrically coupled to the second terminal of the second secondary winding, the first terminal of the seventh switch, the first terminal of the ninth switch, and the first terminal of the output capacitor; and wherein the first terminal of the first primary winding, the first terminal of the first secondary winding, the first terminal of the second secondary winding, and the first terminal of the third secondary winding are terminals of the same name.

[0018] According to an embodiment of this application, when the voltage conversion circuit operates in the first operating mode, the first capacitor is in a charging state.

[0019] According to an embodiment of this application, when the voltage conversion circuit operates in the second operating mode, the first capacitor is in a discharging state.

[0020] According to an embodiment of this application, the first switch, the third switch, the fifth switch, the seventh switch, and the tenth switch are simultaneously turned on or off, and the second switch, the fourth switch, the sixth switch, the eighth switch, and the ninth switch are simultaneously turned on or off.

[0021] According to an embodiment of this application, the number of turns of the first primary winding is denoted as N1; and the number of turns of the first secondary winding, the second secondary winding, and the third secondary winding are the same, denoted as N2, where N1 and N2 are positive integers.

[0022] According to an embodiment of this application, the voltage between the first input terminal and the second input terminal is the input voltage Vin, and the voltage between the first output terminal and the second output terminal is the output voltage Vo. The relationship between the input voltage Vin and the output voltage Vo is as follows:

[0023] Vin / Vo = N + 2, where N = N1 / N2.

[0024] According to an embodiment of this application, the voltage conversion circuit further includes an output load electrically coupled to both ends of the output capacitor.

[0025] According to an embodiment of this application, the voltage conversion circuit further includes an input capacitor electrically coupled between the first input terminal and the second input terminal.

[0026] According to an embodiment of this application, the first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, the eighth switch, the ninth switch, and the tenth switch are MOSFETs. Attached Figure Description

[0027] The above and other aspects, features and advantages of certain embodiments of the present application will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0028] Figure 1 The topology of a conventional voltage conversion circuit is shown.

[0029] Figure 2a A topological example of the voltage conversion circuit according to the first embodiment of this application is shown.

[0030] Figure 2b It shows Figure 2a The diagram shows the operating state of the voltage conversion circuit in the first operating mode.

[0031] Figure 2c It shows Figure 2a The diagram shows the simulation verification waveform of the voltage conversion circuit in the first operating mode.

[0032] Figure 2d It shows Figure 2a The diagram shows the operating state of the voltage conversion circuit in the second operating mode.

[0033] Figure 2e It shows Figure 2a The diagram shows the simulation verification waveform of the voltage conversion circuit in the second operating mode.

[0034] Figure 3a A topological example of a voltage conversion circuit according to the second embodiment of this application is shown.

[0035] Figure 3b It shows Figure 3a The diagram shows the operating state of the voltage conversion circuit in the first operating mode.

[0036] Figure 3c It shows Figure 3a The diagram shows the simulation verification waveform of the voltage conversion circuit in the first operating mode.

[0037] Figure 3d It shows Figure 3a The diagram shows the operating state of the voltage conversion circuit in the second operating mode.

[0038] Figure 3e It shows Figure 3a The diagram shows the simulation verification waveform of the voltage conversion circuit in the second operating mode. Detailed Implementation

[0039] The following description, with reference to the accompanying drawings, is provided to aid in a thorough understanding of the various embodiments of the present application as defined by the claims and their equivalents. This description includes various specific details to aid understanding but should be considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of the present application. Furthermore, for clarity and brevity, descriptions of well-known functions and structures may be omitted.

[0040] The terms and wording used in the following description and claims are not limited to their dictionary meanings, but are merely used by the inventors to enable a clear and consistent understanding of this application. Therefore, it will be apparent to those skilled in the art that the following description of various embodiments of this application is for illustrative purposes only and is not intended to limit the purpose of this application as defined in the appended claims and their equivalents.

[0041] It should be understood that the singular forms of “one,” “an,” and “the” include plural references unless the context clearly indicates otherwise. Thus, for example, the reference to “component surface” includes one or more such surfaces.

[0042] The terms “comprising” or “may include” refer to the presence of a corresponding disclosed function, operation, or component that may be used in the various embodiments of this application, rather than limiting the presence of one or more additional functions, operations, or features. Furthermore, the terms “comprising” or “having” may be interpreted as indicating certain characteristics, numbers, steps, operations, constituent elements, components, or combinations thereof, but should not be construed as excluding the possibility of the presence of one or more other characteristics, numbers, steps, operations, constituent elements, components, or combinations thereof.

[0043] The term "or" as used in the various embodiments of this application includes any of the listed terms and all combinations thereof. For example, "A or B" may include A, may include B, or may include both A and B.

[0044] Unless otherwise defined, all terms used in this application (including technical or scientific terms) have the same meaning as understood by one of those skilled in the art as described herein. Common terms as defined in dictionaries are to be interpreted as having a meaning consistent with the context in the relevant technical field and should not be interpreted ideally or overly formally, unless expressly so defined in this application.

[0045] The figures discussed below, as well as the various embodiments used to illustrate the principles of this application in this patent document, are for illustrative purposes only and should not be construed in any way as limiting the scope of this application. Those skilled in the art will understand that the principles of this application can be implemented in any suitably arranged system or device.

[0046] Figure 1 The topology of a conventional voltage conversion circuit is shown.

[0047] like Figure 1 The conventional voltage converter circuit shown has a primary side consisting of four switching transistors Q1, Q2, Q3, and Q4 forming a standard full-bridge inverter topology, with an input DC voltage V. in The resonant circuit consists of capacitor C. b Resonant inductor L r Magnetizing inductance L m Together, they form an LLC resonant network. The primary winding of the transformer has N1 turns; the secondary winding of the transformer has two sets of equal-number secondary windings (N2 turns), S1 and S2 are full-wave rectifier diodes, and the output capacitor C is also present. o Finally, the output voltage V is obtained. o .

[0048] The steady-state voltage turns ratio of this conventional circuit satisfies V in / V o =N+1, where N is the ratio of the number of turns N1 on the primary winding of the transformer to the number of turns N2 on the secondary winding. Only one of the two sets of secondary windings of this transformer participates in power transmission at any given time, resulting in an effective utilization rate of only 50%. This not only increases the copper losses of the transformer but also exacerbates the switching losses of the switching transistors due to the parasitic parameters of the idle windings. Furthermore, the voltage ratio of this topology is entirely dependent on the ratio of the number of turns on the primary and secondary windings of the transformer. Adjusting the voltage ratio requires changing the number of turns in the windings, which, under high voltage ratio conditions, will increase the size of the magnetic components in the circuit, increase losses, and raise costs.

[0049] Figure 2a A topological example of the voltage conversion circuit according to the first embodiment of this application is shown.

[0050] like Figure 2a The voltage conversion circuit of the first embodiment shown includes a first input terminal Vin+, a second input terminal Vin-, a first output terminal Vo+, a second output terminal Vo-, a first full-bridge circuit, a first resonant branch, a second resonant branch, a first rectifier branch, a second rectifier branch, a second full-bridge circuit, and an output capacitor Cout. The voltage between the first input terminal Vin+ and the second input terminal Vin- is the input voltage Vin, and the voltage between the first output terminal Vo+ and the second output terminal Vo- is the output voltage Vo.

[0051] The second input terminal Vin- can be electrically coupled to the second output terminal Vo-.

[0052] The first full-bridge sub-circuit may include a first left bridge arm and a first right bridge arm. The first left bridge arm may include a first switch Q1 and a second switch Q2 connected in series. The first right bridge arm may include a fourth switch Q4 and a fifth switch Q5 connected in series. The first terminal of the first switch Q1 may be electrically coupled to the first terminal of the fourth switch Q4 and the first input terminal Vin+.

[0053] The first resonant branch may include a first capacitor Cr1 and a first primary winding P1 connected in series. The first end of the first resonant branch may be electrically coupled to the second end of the first switch Q1 and the first end of the second switch Q2, and the second end of the first resonant branch may be electrically coupled to the second end of the fifth switch Q5. The second resonant branch may include a second capacitor Cr2 and a second primary winding P2 connected in series. The first end of the second resonant branch may be electrically coupled to the second end of the fourth switch Q4 and the first end of the fifth switch Q5, and the second end of the second resonant branch may be electrically coupled to the second end of the second switch Q2.

[0054] The first rectifier branch may include a first secondary winding S1 and a third switch Q3 connected in series, wherein the second end of the first resonant branch may be electrically coupled to the second end of the first secondary winding S1 and the first end of the third switch Q3; the second rectifier branch may include a second secondary winding S2 and a sixth switch Q6 connected in series, wherein the second end of the first resonant branch may be electrically coupled to the first end of the second secondary winding S2 and the first end of the sixth switch Q6, and wherein the first end of the first rectifier branch may be electrically coupled to the first end of the second rectifier branch.

[0055] The second full-bridge sub-circuit may include a second left bridge arm, a second right bridge arm, and a third secondary winding. The second left bridge arm may include a seventh switch Q7 and an eighth switch Q8 connected in series. The second right bridge arm may include a ninth switch Q9 and a tenth switch Q10 connected in series. The first end of the third secondary winding S3 may be electrically coupled to the second end of the seventh switch Q7 and the first end of the eighth switch Q8. The second end of the third secondary winding S3 may be electrically coupled to the second end of the ninth switch Q9 and the first end of the tenth switch Q10.

[0056] The first terminal of the output capacitor Cout can be electrically coupled to the first terminal of the first rectifier branch, the first terminal of the second rectifier branch, the first terminal of the seventh switch Q7, the first terminal of the ninth switch Q9, and the first output terminal Vo+; the second terminal of the output capacitor Cout can be electrically coupled to the second terminal of the first rectifier branch, the second terminal of the second rectifier branch, the second terminal of the eighth switch Q8, the second terminal of the tenth switch Q10, and the second output terminal Vo-.

[0057] According to an embodiment of this application, the first terminal of the first capacitor Cr1 can be electrically coupled to the second terminal of the first switch Q1, and the second terminal of the first capacitor Cr1 can be electrically coupled to the first terminal of the first primary winding P1. The first terminal of the second capacitor Cr2 can be electrically coupled to the second terminal of the fourth switch Q4, and the second terminal of the second capacitor Cr2 can be electrically coupled to the second terminal of the second primary winding P2. It should be noted that the positions of the first capacitor Cr1 and the first primary winding P1 in the first resonant branch can be interchanged, as long as they are connected in series. Similarly, the positions of the second capacitor Cr2 and the second primary winding P2 in the second resonant branch can be interchanged, as long as they are connected in series.

[0058] According to an embodiment of this application, the second end of the first primary winding P1 can be electrically coupled to the first end of the second secondary winding S2, the second end of the fifth switch Q5, and the first end of the sixth switch Q6; the first end of the second primary winding P2 can be electrically coupled to the second end of the first secondary winding S1, the second end of the second switch Q2, and the first end of the third switch Q3; the first end of the first secondary winding S1 can be electrically coupled to the second end of the second secondary winding S2, the first end of the seventh switch Q7, the first end of the ninth switch Q9, and the first end of the output capacitor Cout; the second end of the first secondary winding S1 can be electrically coupled to the second end of the second switch Q2 and the first end of the third switch Q3; and the first end of the second secondary winding S2 can be electrically coupled to the second end of the fifth switch Q5 and the first end of the sixth switch Q6.

[0059] According to an embodiment of this application, the first end of the first primary winding P1, the first end of the second primary winding P2, the first end of the first secondary winding S1, the first end of the second secondary winding S2, and the first end of the third secondary winding S3 can be the same end.

[0060] According to the embodiments of this application, the first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7 and the tenth switch Q10 can be turned on or off simultaneously, and the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8 and the ninth switch Q9 can be turned on or off simultaneously.

[0061] According to embodiments of this application, the voltage conversion circuit may further include an output load Rload electrically coupled to both ends of the output capacitor Cout.

[0062] According to embodiments of this application, the voltage conversion circuit may further include an input capacitor electrically coupled between the first input terminal Vin+ and the second input terminal Vin-.

[0063] According to the embodiments of this application, the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, the eighth switch Q8, the ninth switch Q9, and the tenth switch Q10 can be MOSFETs or any switching transistors that can perform the relevant functions, such as insulated gate bipolar transistors (IGBTs), power bipolar transistors (BJTs), or high-frequency fast thyristors.

[0064] The following is for reference Figure 2b and 2c Explain each Figure 2a The working principle and simulation results of the voltage conversion circuit shown are presented in the first operating mode.

[0065] like Figure 2b As shown, in the first operating mode, for example, during the positive half-cycle:

[0066] The first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10 are in the on state, while the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9 are in the off state.

[0067] The first capacitor Cr1 is in a charging state, and the current ICr1 flows into the first terminal of the first primary winding P1. The second capacitor Cr2 is in a discharging state, and the current ICr2 flows into the second terminal of the second primary winding P2. In addition, ICr1 and ICr2 also flow into the first terminal of the second secondary winding S2. Is1, Is2, and Is3 are the currents flowing through the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3, respectively, and Is2 = ICr1 + ICr2.

[0068] Let the number of turns of the first primary winding P1 and the second primary winding P2 be equal, denoted as N1. Let the number of turns of the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3 be equal, denoted as N2, where N1 and N2 are positive integers. Furthermore, the first capacitor Cr1 and the second capacitor Cr2 are equal, i.e., Cr1 = Cr2. Since Cr1 and Cr2 are equal, the currents ICr1 and ICr2 are also equal, denoted as i. Therefore, the following equation can be obtained:

[0069] Is2 = ICr1 + ICr2 = 2i (1-1)

[0070] According to the magnetomotive force balance equation, the following equation can be obtained:

[0071] N1 ICr1+N1 ICr2+N2 Is2=N2 (Is1+Is3) (1-2)

[0072] Substituting equation (1-1) into equation (1-2), we get:

[0073] N1 i+N1 i+N2 Is2=N2 (Is1+Is3) (1-3)

[0074] Combining and rearranging equations (1-3), and denoting the turns ratio N1 / N2 as N, we get N = N1 / N2. Substituting these equations, we obtain:

[0075] Is1 + Is3 = (2N + 2) i (1-4)

[0076] The total output current Iout = Is1 + Is2 + Is3. Substituting this into equation (1-4), we get:

[0077] Iout = (2N + 4) i (1-5)

[0078] According to the law of conservation of power, input power equals output power, Pin = Pout, that is, Vin i=Vo Substituting Iout into equation (1-5), we can obtain the voltage ratio as follows:

[0079] Vin / Vo = 2N + 4, where N = N1 / N2 (1-6)

[0080] like Figure 2c As shown, in the first operating mode, such as the positive half-cycle, the voltage conversion circuit simultaneously turns on the first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10, while simultaneously turning off the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9, thereby forming... Figure 2b The current transmission path during the positive half-cycle is shown.

[0081] Specifically, refer to Figure 2c and combined Figure 2bDuring the positive half-cycle, the first capacitor Cr1 is in a charging state, and the current ICr1 flowing through the first capacitor Cr1 flows through the first primary winding P1 to the first terminal of the second secondary winding S2. Simultaneously, the second capacitor Cr2 is in a discharging state, and the current ICr2 flowing through the second capacitor Cr2 flows through the fifth switch Q5 to the first terminal of the second secondary winding S2. The number of turns in the first primary winding P1 and the second primary winding P2 are set to be equal (N1), and the number of turns in the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3 are set to be equal (N2). Since the first capacitor Cr1 and the second capacitor Cr2 are equal, the currents ICr1 and ICr2 are also equal. Figure 2c The waveforms of currents ICr1 and ICr2 shown also verify that the amplitudes of currents ICr1 and ICr2 are equal, but their directions are opposite.

[0082] Based on the derived voltage ratio formula (1-6), the ratio of input voltage Vin to output voltage Vo is Vin / Vo = 2N + 4, where N = N1 / N2. When N = 1, Vin / Vo = 6. (Reference) Figure 2c The waveforms of the input voltage Vin and the output voltage Vo shown indicate that when N=1, Vin≈48V, Vo≈8V, and Vin / Vo≈6, i.e. Figure 2c The simulation results also verified the above input-output voltage ratio.

[0083] The following is for reference Figure 2d and 2e Explain each Figure 2a The working principle and simulation results of the voltage conversion circuit shown in the second operating mode are presented.

[0084] like Figure 2d As shown, in the second operating mode, for example, in the negative half-cycle:

[0085] The first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10 are in the off state, while the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9 are in the on state.

[0086] The first capacitor Cr1 is in a discharging state, and current ICr1 flows into the second terminal of the first primary winding P1. The second capacitor Cr2 is in a charging state, and current ICr2 flows into the second terminal of the second primary winding P2. In addition, currents ICr1 and ICr2 simultaneously flow into the second terminal of the first secondary winding S1. Is1, Is2, and Is3 are the currents flowing through the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3, respectively. Therefore, Is1 = ICr1 + ICr2.

[0087] Based on a derivation method similar to that of the first working mode, according to the magnetomotive force balance equation (1-2), it can be obtained that in the second working mode, the voltage ratio of the voltage conversion circuit is the same as that in the first working mode, which is: Vin / Vo=2N+4, where N=N1 / N2.

[0088] like Figure 2e As shown, in the second operating mode, such as the negative half-cycle, the voltage conversion circuit simultaneously turns off the first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10, while simultaneously turning on the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9, thereby forming... Figure 2d The current transmission path during the negative half-cycle is shown.

[0089] Specifically, refer to Figure 2e and combined Figure 2d During the negative half-cycle, the first capacitor Cr1 is in a discharging state, and the current ICr1 flowing through the first capacitor Cr1 flows through the second switch Q2 to the second terminal of the first secondary winding S1. Simultaneously, the second capacitor Cr2 is in a charging state, and the current ICr2 flowing through the second capacitor Cr2 flows through the second primary winding P2 to the second terminal of the first secondary winding S1. The number of turns in the first primary winding P1 and the second primary winding P2 are set to be equal (N1), and the number of turns in the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3 are set to be equal (N2). Since the first capacitor Cr1 and the second capacitor Cr2 are equal, the currents ICr1 and ICr2 are also equal. Figure 2e The waveforms of currents ICr1 and ICr2 shown also verify that the amplitudes of currents ICr1 and ICr2 are equal, but their directions are opposite.

[0090] Based on the derived voltage ratio formula (1-6), the ratio of input voltage Vin to output voltage Vo is Vin / Vo = 2N + 4, where N = N1 / N2. When N = 1, Vin / Vo = 6. (Reference) Figure 2e The waveforms of the input voltage Vin and the output voltage Vo shown indicate that when N=1, Vin≈48V, Vo≈8V, and Vin / Vo≈6, i.e. Figure 2e The simulation results also verified the above input-output voltage ratio.

[0091] Figure 3a A topological example of a voltage conversion circuit according to the second embodiment of this application is shown.

[0092] like Figure 3aThe voltage conversion circuit of the second embodiment shown includes a first input terminal Vin+, a second input terminal Vin-, a first output terminal Vo+, a second output terminal Vo-, a first full-bridge circuit, a resonant branch, a first rectifier branch, a second rectifier branch, a second full-bridge circuit, and an output capacitor Cout. The voltage between the first input terminal Vin+ and the second input terminal Vin- is the input voltage Vin, and the voltage between the first output terminal Vo+ and the second output terminal Vo- is the output voltage Vo.

[0093] The second input terminal Vin- can be electrically coupled to the second output terminal Vo-.

[0094] The first full-bridge sub-circuit may include a first left bridge arm and a first right bridge arm. The first left bridge arm may include a first switch Q1 and a second switch Q2 connected in series. The first right bridge arm may include a fourth switch Q4 and a fifth switch Q5 connected in series. The first terminal of the first switch Q1 may be electrically coupled to the first terminal of the fourth switch Q4 and the first input terminal Vin+.

[0095] The resonant branch may include a first capacitor Cr1 and a first primary winding P1 connected in series. The first end of the resonant branch may be electrically coupled to the second end of the first switch Q1 and the first end of the second switch Q2. The second end of the resonant branch may be electrically coupled to the second end of the fourth switch Q4 and the first end of the fifth switch Q5.

[0096] The first rectifier branch may include a first secondary winding S1 and a third switch Q3 connected in series, wherein the second end of the second switch Q2 may be electrically coupled to the second end of the first secondary winding S1 and the first end of the third switch Q3; the second rectifier branch may include a second secondary winding S2 and a sixth switch Q6 connected in series, wherein the second end of the fifth switch Q5 may be electrically coupled to the first end of the second secondary winding S2 and the first end of the sixth switch Q6.

[0097] The second full-bridge sub-circuit may include a second left bridge arm, a second right bridge arm, and a third secondary winding S3. The second left bridge arm may include a seventh switch Q7 and an eighth switch Q8 connected in series. The second right bridge arm may include a ninth switch Q9 and a tenth switch Q10 connected in series. The first end of the third secondary winding S3 may be electrically coupled to the second end of the seventh switch Q7 and the first end of the eighth switch Q8. The second end of the third secondary winding S3 may be electrically coupled to the second end of the ninth switch Q9 and the first end of the tenth switch Q10.

[0098] The first terminal of the output capacitor Cout can be electrically coupled to the first terminal of the first rectifier branch, the first terminal of the second rectifier branch, the first terminal of the seventh switch Q7, the first terminal of the ninth switch Q9, and the first output terminal Vo+; the second terminal of the output capacitor Cout can be electrically coupled to the second terminal of the first rectifier branch, the second terminal of the second rectifier branch, the second terminal of the eighth switch Q8, the second terminal of the tenth switch Q10, and the second output terminal Vo-.

[0099] According to an embodiment of this application, the first terminal of the first capacitor Cr1 can be electrically coupled to the second terminal of the first switch Q1, and the second terminal of the first capacitor Cr1 can be electrically coupled to the first terminal of the first primary winding P1. It should be noted that the positions of the first capacitor Cr1 and the first primary winding P1 in the resonant branch can be interchanged, as long as they are connected in series.

[0100] According to an embodiment of this application, the second end of the first primary winding P1 can be electrically coupled to the second end of the fourth switch Q4 and the first end of the fifth switch Q5; the first end of the first secondary winding S1 can be electrically coupled to the second end of the second secondary winding S2, the first end of the seventh switch Q7, the first end of the ninth switch Q9 and the first end of the output capacitor Cout.

[0101] According to an embodiment of this application, the first end of the first primary winding P1, the first end of the first secondary winding S1, the first end of the second secondary winding S2, and the first end of the third secondary winding S3 can be the same end.

[0102] According to the embodiments of this application, the first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7 and the tenth switch Q10 can be turned on or off simultaneously, and the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8 and the ninth switch Q9 can be turned on or off simultaneously.

[0103] According to embodiments of this application, the voltage conversion circuit may further include an output load Rload electrically coupled to both ends of the output capacitor Cout.

[0104] According to embodiments of this application, the voltage conversion circuit may further include an input capacitor electrically coupled between the first input terminal Vin+ and the second input terminal Vin-.

[0105] According to the embodiments of this application, the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, the eighth switch Q8, the ninth switch Q9, and the tenth switch Q10 can be MOSFETs or any switching transistors that can perform the relevant functions, such as insulated gate bipolar transistors (IGBTs), power bipolar transistors (BJTs), or high-frequency fast thyristors.

[0106] The following is for reference Figure 3b and 3c Explain each Figure 3a The working principle and simulation results of the voltage conversion circuit shown are presented in the first operating mode.

[0107] like Figure 3b As shown, in the first operating mode, for example, during the positive half-cycle:

[0108] The first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10 are in the on state, while the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9 are in the off state.

[0109] The first capacitor Cr1 is in a charging state. Current ICr1 flows into the first end of the first primary winding P1 and the first end of the second secondary winding S2. Currents Is1, Is2 and Is3 are the currents flowing through the first secondary winding S1, the second secondary winding S2 and the third secondary winding S3 respectively. ICr1 = Is2.

[0110] The number of turns in the first primary winding P1 is denoted as N1, and the number of turns in the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3 are equal, denoted as N2, where N1 and N2 are positive integers. Furthermore, assuming the current ICr1 is i, the following equation can be obtained:

[0111] ICr1=Is2=i (2-1)

[0112] According to the magnetomotive force balance equation, the following equation can be obtained:

[0113] N1 ICr1+N2 Is2=N2 (Is1+Is3) (2-2)

[0114] Substituting equation (2-1) into equation (2-2), we get:

[0115] N1 i+N2 i=N2 (Is1+Is3) (2-3)

[0116] Combining and rearranging equations (2-3), and denoting the turns ratio N1 / N2 as N, i.e., N=N1 / N2, we can obtain:

[0117] Is1 + Is3 = (N + 1) i (2-4)

[0118] The total output current Iout = Is1 + Is2 + Is3. Substituting this into equation (2-4), we get:

[0119] Iout = (N+2) i (2-5)

[0120] According to the law of conservation of power, input power equals output power, Pin = Pout, that is, Vin i=Vo Substituting Iout into equation (2-5), we can obtain the voltage ratio as follows:

[0121] Vin / Vo = N + 2, where N = N1 / N2 (2-6)

[0122] like Figure 3c As shown, in the first operating mode, such as the positive half-cycle, the voltage conversion circuit simultaneously turns on the first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10, while simultaneously turning off the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9, thereby forming... Figure 3b The current transmission path during the positive half-cycle is shown.

[0123] Specifically, refer to Figure 3c and combined Figure 3b During the positive half-cycle, the first capacitor Cr1 is in a charging state, and the current ICr1 flowing through the first capacitor Cr1 flows through the first primary winding P1 and the fifth switch Q5 to the first end of the second secondary winding S2. The number of turns of the first primary winding P1 is set to N1, and the number of turns of the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3 are equal (N2). Figure 3c A schematic diagram of the current ICr1 waveform in this case is shown.

[0124] Based on the derived voltage ratio formula (2-6), the ratio of input voltage Vin to output voltage Vo is Vin / Vo = N + 2, where N = N1 / N2. When N = 1, Vin / Vo = 3. (Reference) Figure 3c The waveforms of the input voltage Vin and the output voltage Vo shown indicate that when N=1, Vin≈48V, Vo≈16V, and Vin / Vo≈3, i.e. Figure 3c The simulation results also verified the above input-output voltage ratio.

[0125] The following is for reference Figure 3d and 3e Explain each Figure 3a The working principle and simulation results of the voltage conversion circuit shown in the second operating mode are presented.

[0126] like Figure 3dAs shown, in the second operating mode, for example, in the negative half-cycle:

[0127] The first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10 are in the off state, while the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9 are in the on state.

[0128] The first capacitor Cr1 is in a discharging state, and the current ICr1 flows into the second end of the first primary winding P1 and the second end of the first secondary winding S1. Is1, Is2 and Is3 are the currents flowing through the first secondary winding S1, the second secondary winding S2 and the third secondary winding S3 respectively, and ICr1 = Is1.

[0129] Based on a derivation method similar to that of the first operating mode, and based on the magnetomotive force balance equation (2-2), it can be obtained that in the second operating mode, the voltage ratio of the voltage conversion circuit is the same as that in the first operating mode, which is: Vin / Vo=N+2, where N=N1 / N2.

[0130] like Figure 3e As shown, in the second operating mode, for example, during the negative half-cycle, the first switch Q1, the third switch Q3, the fifth switch Q5, the seventh switch Q7, and the tenth switch Q10 are simultaneously turned off, while the second switch Q2, the fourth switch Q4, the sixth switch Q6, the eighth switch Q8, and the ninth switch Q9 are simultaneously turned on, thereby forming... Figure 3d The current transmission path during the negative half-cycle is shown.

[0131] Specifically, refer to Figure 3e and combined Figure 3d During the negative half-cycle, the first capacitor Cr1 is in a discharging state, and the current ICr1 flowing through the first capacitor Cr1 flows to the second end of the first secondary winding S1 through the second switch Q2. The number of turns of the first primary winding P1 is set to N1, and the number of turns of the first secondary winding S1, the second secondary winding S2, and the third secondary winding S3 are equal (N2). Figure 3c A schematic diagram of the current ICr1 waveform in this case is shown.

[0132] Based on the derived voltage ratio formula (2-6), the ratio of input voltage Vin to output voltage Vo is Vin / Vo = N + 2, where N = N1 / N2. When N = 1, Vin / Vo = 3. (Reference) Figure 3e The waveforms of the input voltage Vin and the output voltage Vo shown indicate that when N=1, Vin≈48V, Vo≈16V, and Vin / Vo≈3, i.e. Figure 3e The simulation results also verified the above input-output voltage ratio.

[0133] It should be noted that the voltage conversion circuits in this application include, but are not limited to, half-bridge LLC resonant converter circuits, full-bridge LLC resonant converter circuits, and phase-shifted full-bridge circuits.

[0134] In summary, the voltage conversion circuit provided in this application overcomes the technical limitation of traditional voltage conversion circuits that achieve large integer voltage ratios by increasing the number of turns in the transformer winding. It achieves large integer voltage ratios without requiring a transformer with a large turns ratio. This solution eliminates the need to increase the number of transformer winding turns, which helps reduce winding length, effectively reduces winding copper losses and magnetic component losses, and improves the conversion efficiency of the voltage conversion circuit. Simultaneously, it reduces the transformer winding height and overall volume, increases power density, and reduces manufacturing costs. Furthermore, it lowers the withstand voltage requirements for some power devices, broadens the device selection range, and further reduces device costs.

[0135] In this application, in order to avoid unnecessarily obscuring the scope of this application, content unrelated to the technical concept of this application has been omitted.

[0136] Although this application has been described with reference to exemplary embodiments, various changes and modifications may be suggested to those skilled in the art. This application is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0137] Nothing described in this application should be construed as implying that any particular element, step, or function is an essential element that must be included within the scope of the claims. The scope of the patent subject matter is defined only by the claims.

[0138] Exemplary embodiments according to this application have been disclosed herein, and although specific terminology has been used, it is used and interpreted in a general and descriptive sense only and not for limiting purposes. In some instances, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise stated. Therefore, those skilled in the art will understand that various changes in form and detail may be made to this application without departing from the spirit and scope of the claims.

Claims

1. A voltage conversion circuit, the circuit comprising: The system comprises a first input terminal, a second input terminal, a first output terminal, and a second output terminal, wherein the second input terminal is electrically coupled to the second output terminal. The first full-bridge circuit includes a first left bridge arm and a first right bridge arm, wherein the first left bridge arm includes a first switch and a second switch connected in series; the first right bridge arm includes a fourth switch and a fifth switch connected in series; and wherein the first terminal of the first switch is electrically coupled to the first terminal of the fourth switch and the first input terminal. The first resonant branch includes a first capacitor and a first primary winding connected in series, wherein the first end of the first resonant branch is electrically coupled to the second end of the first switch and the first end of the second switch, and the second end of the first resonant branch is electrically coupled to the second end of the fifth switch. The second resonant branch includes a second capacitor and a second primary winding connected in series. The first end of the second resonant branch is electrically coupled to the second end of the fourth switch and the first end of the fifth switch, and the second end of the second resonant branch is electrically coupled to the second end of the second switch. The first rectifier branch includes a first secondary winding and a third switch connected in series, wherein the second end of the second resonant branch is electrically coupled to the second end of the first secondary winding and the first end of the third switch; The second rectifier branch includes a second secondary winding and a sixth switch connected in series, wherein the second end of the first resonant branch is electrically coupled to the first end of the second secondary winding and the first end of the sixth switch, and wherein the first end of the first rectifier branch is electrically coupled to the first end of the second rectifier branch. The second full-bridge circuit includes a second left bridge arm, a second right bridge arm, and a third secondary winding. The second left bridge arm includes a seventh switch and an eighth switch connected in series; the second right bridge arm includes a ninth switch and a tenth switch connected in series; the first terminal of the third secondary winding is electrically coupled to the second terminal of the seventh switch and the first terminal of the eighth switch; the second terminal of the third secondary winding is electrically coupled to the second terminal of the ninth switch and the first terminal of the tenth switch. An output capacitor, wherein the first end of the output capacitor is electrically coupled to the first end of the first rectifier branch, the first end of the second rectifier branch, the first end of the seventh switch, the first end of the ninth switch, and the first output terminal; and the second end of the output capacitor is electrically coupled to the second end of the first rectifier branch, the second end of the second rectifier branch, the second end of the eighth switch, the second end of the tenth switch, and the second output terminal.

2. The voltage conversion circuit as described in claim 1, wherein, The first terminal of the first capacitor is electrically coupled to the second terminal of the first switch, the second terminal of the first capacitor is electrically coupled to the first terminal of the first primary winding, the first terminal of the second capacitor is electrically coupled to the second terminal of the fourth switch, and the second terminal of the second capacitor is electrically coupled to the second terminal of the second primary winding. The second end of the first primary winding is electrically coupled to the first end of the second secondary winding, the second end of the fifth switch, and the first end of the sixth switch; the first end of the second primary winding is electrically coupled to the second end of the first secondary winding, the second end of the second switch, and the first end of the third switch; the first end of the first secondary winding is electrically coupled to the second end of the second secondary winding, the first end of the seventh switch, the first end of the ninth switch, and the first end of the output capacitor; the second end of the first secondary winding is electrically coupled to the second end of the second switch and the first end of the third switch; the first end of the second secondary winding is electrically coupled to the second end of the fifth switch and the first end of the sixth switch. and Wherein, the first end of the first primary winding, the first end of the second primary winding, the first end of the first secondary winding, the first end of the second secondary winding, and the first end of the third secondary winding are the same-named ends.

3. The voltage conversion circuit as described in claim 1 or 2, wherein, When the voltage conversion circuit operates in the first operating mode, the first capacitor operates in the charging state, and the second capacitor operates in the discharging state.

4. The voltage conversion circuit as described in claim 1 or 2, wherein, When the voltage conversion circuit operates in the second operating mode, the second capacitor operates in the charging state, and the first capacitor operates in the discharging state.

5. The voltage conversion circuit as described in claim 1 or 2, wherein, The first switch, the third switch, the fifth switch, the seventh switch, and the tenth switch are simultaneously turned on or off, and the second switch, the fourth switch, the sixth switch, the eighth switch, and the ninth switch are simultaneously turned on or off.

6. The voltage conversion circuit as described in claim 1 or 2, wherein, The number of turns of the first primary winding is the same as the number of turns of the second primary winding, denoted as N1; and The number of turns in the first secondary winding, the second secondary winding, and the third secondary winding are the same, denoted as N2, where N1 and N2 are positive integers.

7. The voltage conversion circuit as described in claim 6, wherein, The voltage between the first input terminal and the second input terminal is the input voltage Vin, and the voltage between the first output terminal and the second output terminal is the output voltage Vo. The relationship between the input voltage Vin and the output voltage Vo is as follows: Vin / Vo = 2N + 4, where N = N1 / N2.

8. The voltage conversion circuit as described in any one of claims 1, 2 or 7 further includes an output load electrically coupled to both ends of the output capacitor.

9. The voltage conversion circuit as described in any one of claims 1, 2, or 7, further comprising: An input capacitor is electrically coupled between the first input terminal and the second input terminal.

10. The voltage conversion circuit as described in any one of claims 1, 2, or 7, wherein, The first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, the eighth switch, the ninth switch, and the tenth switch are MOSFETs.

11. A voltage conversion circuit, the circuit comprising: The system comprises a first input terminal, a second input terminal, a first output terminal, and a second output terminal, wherein the second input terminal is electrically coupled to the second output terminal. The first full-bridge circuit includes a first left bridge arm and a first right bridge arm, wherein the first left bridge arm includes a first switch and a second switch connected in series; the first right bridge arm includes a fourth switch and a fifth switch connected in series; and wherein the first terminal of the first switch is electrically coupled to the first terminal of the fourth switch and the first input terminal. A resonant branch includes a first capacitor and a first primary winding connected in series, wherein the first end of the resonant branch is electrically coupled to the second end of the first switch and the first end of the second switch, and the second end of the resonant branch is electrically coupled to the second end of the fourth switch and the first end of the fifth switch; The first rectifier branch includes a first secondary winding and a third switch connected in series, wherein the second terminal of the second switch is electrically coupled to the second terminal of the first secondary winding and the first terminal of the third switch; The second rectifier branch includes a second secondary winding and a sixth switch connected in series, wherein the first end of the first rectifier branch is electrically coupled to the first end of the second rectifier branch, and the second end of the fifth switch is electrically coupled to the first end of the second secondary winding and the first end of the sixth switch; The second full-bridge circuit includes a second left bridge arm, a second right bridge arm, and a third secondary winding. The second left bridge arm includes a seventh switch and an eighth switch connected in series; the second right bridge arm includes a ninth switch and a tenth switch connected in series; the first terminal of the third secondary winding is electrically coupled to the second terminal of the seventh switch and the first terminal of the eighth switch; the second terminal of the third secondary winding is electrically coupled to the second terminal of the ninth switch and the first terminal of the tenth switch. An output capacitor, wherein the first end of the output capacitor is electrically coupled to the first end of the first rectifier branch, the first end of the second rectifier branch, the first end of the seventh switch, the first end of the ninth switch, and the first output terminal; and the second end of the output capacitor is electrically coupled to the second end of the first rectifier branch, the second end of the second rectifier branch, the second end of the eighth switch, the second end of the tenth switch, and the second output terminal.

12. The voltage conversion circuit as described in claim 11, wherein, The first terminal of the first capacitor is electrically coupled to the second terminal of the first switch, and the second terminal of the first capacitor is electrically coupled to the first terminal of the first primary winding. The second end of the first primary winding is electrically coupled to the second end of the fourth switch and the first end of the fifth switch; the first end of the first secondary winding is electrically coupled to the second end of the second secondary winding, the first end of the seventh switch, the first end of the ninth switch and the first end of the output capacitor; and Wherein, the first end of the first primary winding, the first end of the first secondary winding, the first end of the second secondary winding, and the first end of the third secondary winding are the same name ends.

13. The voltage conversion circuit as described in claim 11 or 12, wherein, When the voltage conversion circuit operates in the first operating mode, the first capacitor is in a charging state.

14. The voltage conversion circuit as described in claim 11 or 12, wherein, When the voltage conversion circuit operates in the second operating mode, the first capacitor is in a discharging state.

15. The voltage conversion circuit as described in claim 11 or 12, wherein, The first switch, the third switch, the fifth switch, the seventh switch, and the tenth switch are simultaneously turned on or off, and the second switch, the fourth switch, the sixth switch, the eighth switch, and the ninth switch are simultaneously turned on or off.

16. The voltage conversion circuit as described in claim 11 or 12, wherein, The number of turns of the first primary winding is denoted as N1; and The number of turns in the first secondary winding, the second secondary winding, and the third secondary winding are the same, denoted as N2, where N1 and N2 are positive integers.

17. The voltage conversion circuit as described in claim 16, wherein, The voltage between the first input terminal and the second input terminal is the input voltage Vin, and the voltage between the first output terminal and the second output terminal is the output voltage Vo. The relationship between the input voltage Vin and the output voltage Vo is as follows: Vin / Vo = N + 2, where N = N1 / N2.

18. The voltage conversion circuit as described in any one of claims 11, 12 or 17, further comprising an output load electrically coupled to both ends of the output capacitor.

19. The voltage conversion circuit as described in any one of claims 11, 12, or 17, further comprising: An input capacitor is electrically coupled between the first input terminal and the second input terminal.

20. The voltage conversion circuit as described in any one of claims 11, 12, or 17, wherein, The first switch, the second switch, the third switch, the fourth switch, the fifth switch, the sixth switch, the seventh switch, the eighth switch, the ninth switch, and the tenth switch are MOSFETs.

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