Resonant converter based on switched capacitor, method and train

Abstract

The invention provides a resonant converter based on a switched capacitor, a method and a train, which can be applied to the technical field of power electronics and converters. The resonant converter comprises a resonant circuit and a switched capacitor circuit, wherein the input end of the resonant circuit is connected with the input end of the switched capacitor circuit in series, the output end of the resonant circuit is connected with the output end of the switched capacitor circuit in parallel, the switched capacitor circuit comprises N switched capacitor sub-circuits which are connected in series, and the switched capacitor circuit is used for switching the N switched capacitor sub-circuits according to the input voltage of the resonant converter and the voltage gain range of the resonant circuit. And the working states of the N switched capacitor sub-circuits are controlled, so that the gain of the resonant circuit to the input voltage is kept in a voltage gain range, and N is a positive integer.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power electronics and converters, and more particularly, to a switched capacitor-based resonant converter, method and train. Background Art

[0002] Logical Link Control Resonant Converter (LLCRC) is widely used in high-frequency and high-efficiency applications due to its excellent soft switching characteristics. However, the working efficiency of LLCR is relatively good near the resonant frequency. Therefore, in the face of wide-range voltage regulation requirements, the conversion efficiency of LLCR will decrease and the design difficulty of magnetic components will increase. Summary of the invention

[0003] In view of this, the present disclosure provides a switched capacitor based resonant converter, method and train.

[0004] One aspect of the present disclosure provides a switched capacitor based resonant converter, comprising a resonant circuit and a switched capacitor circuit;

[0005] Among them, the input end of the above-mentioned resonant circuit is connected in series with the input end of the above-mentioned switched capacitor circuit, the output end of the above-mentioned resonant circuit is connected in parallel with the output end of the above-mentioned switched capacitor circuit, the above-mentioned switched capacitor circuit includes N switched capacitor sub-circuits connected in series, and the above-mentioned switched capacitor circuit is used to control the working states of the N above-mentioned switched capacitor sub-circuits according to the input voltage of the above-mentioned resonant converter and the voltage gain range of the above-mentioned resonant circuit, so that the gain of the above-mentioned resonant circuit to the above-mentioned input voltage is maintained within the above-mentioned voltage gain range, and N is a positive integer.

[0006] According to an embodiment of the present disclosure, the above-mentioned switch capacitor subcircuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a switch capacitor;

[0007] The first end of the first switch tube is connected to the input end of the switch capacitor circuit, the second end of the first switch tube is connected to the first end of the second switch tube and the first end of the switch capacitor, the first end of the third switch tube is connected to the input end of the switch capacitor circuit, the second end of the third switch tube is connected to the first end of the fourth switch tube and the second end of the switch capacitor, and the second end of the second switch tube is connected to the second end of the fourth switch tube.

[0008] According to an embodiment of the present disclosure, each of the above-mentioned switching capacitor sub-circuit is connected to a bus capacitor, the first end of the above-mentioned bus capacitor is connected to the first end of the above-mentioned first switching tube, the second end of the above-mentioned bus capacitor is connected to the first end of the above-mentioned third switching tube, and the above-mentioned bus capacitor is used to filter the voltage input to the above-mentioned switching capacitor sub-circuit.

[0009] According to an embodiment of the present disclosure, the working states of the above-mentioned switching capacitor subcircuit include a first on-state, a second on-state and a short-circuit state. In the above-mentioned first on-state or the above-mentioned second on-state, the voltage gain of the above-mentioned switching capacitor subcircuit is 1 / 2.

[0010] According to an embodiment of the present disclosure, in the first on state, the first switch tube and the fourth switch tube are turned on, the second switch tube and the third switch tube are turned off, and the input voltage supplies power to the switch capacitor and the load;

[0011] In the second on state, the second switch tube and the third switch tube are turned on, the first switch tube and the fourth switch tube are turned off, and the switch capacitor supplies power to the load;

[0012] In the short-circuit state, the first switch tube and the second switch tube are turned on, and the third switch tube and the fourth switch tube are turned off.

[0013] According to an embodiment of the present disclosure, the above-mentioned switched capacitor circuit is used to determine M target switched capacitor subcircuits from the N above-mentioned switched capacitor subcircuits according to the above-mentioned input voltage of the above-mentioned resonant converter and the above-mentioned voltage gain range of the above-mentioned resonant circuit, wherein the M above-mentioned target switched capacitor subcircuits are in the above-mentioned first conduction state or the second conduction state, and NM non-target switched capacitor subcircuits are in a short-circuit state, so that the gain of the above-mentioned resonant circuit to the above-mentioned input voltage is maintained in the above-mentioned voltage gain range, and the voltage gain of the M above-mentioned target switched capacitor subcircuits is 1 / 2M, and M is a positive integer less than or equal to N.

[0014] According to an embodiment of the present disclosure, the resonant circuit includes a fifth switch tube, a sixth switch tube, a resonant inductor, a resonant capacitor, an excitation inductor, a transformer, a first diode, and a second diode;

[0015] The first end of the fifth switch tube is connected to the input end of the resonant circuit, the second end of the fifth switch tube is connected to the first end of the sixth switch tube, the second end of the sixth switch tube is connected to the input end of the resonant circuit, the first end of the resonant inductor is connected to the second end of the fifth switch tube, the second end of the resonant inductor is connected to the first end of the excitation inductor, the first end of the resonant capacitor is connected to the second end of the sixth switch tube, the second end of the resonant capacitor is connected to the second end of the excitation inductor, the excitation inductor is connected to the primary side of the transformer, the first end of the secondary side of the transformer is connected to the first end of the first diode, the second end of the secondary side of the transformer is connected to the first end of the second diode, and the second end of the first diode and the second end of the second diode are grounded.

[0016] According to an embodiment of the present disclosure, the half-bridge inverter circuit composed of the fifth switch tube and the sixth switch tube inverts the voltage input to the resonant circuit into a square wave voltage, the square wave voltage generates a sinusoidal resonant current through a resonant network composed of the resonant inductor and the resonant capacitor, the square wave voltage generates a triangular wave excitation current on the excitation inductor, the current component after subtracting the sinusoidal wave resonant current from the triangular wave excitation current is transmitted to the secondary side through the primary side of the transformer, and then supplies power to the load through the full-wave rectifier circuit composed of the first diode and the second diode.

[0017] Another aspect of the present disclosure provides a switched capacitor-based resonant conversion method, which is applied to the above-mentioned resonant converter, wherein the above-mentioned resonant converter includes a resonant circuit and a switched capacitor circuit; the above-mentioned method includes:

[0018] The above-mentioned switched capacitor circuit is used to control the working states of the N above-mentioned switched capacitor sub-circuits according to the input voltage of the above-mentioned resonant converter and the voltage gain range of the above-mentioned resonant circuit, so that the gain of the above-mentioned resonant circuit to the above-mentioned input voltage is maintained in the above-mentioned voltage gain range, wherein the input end of the above-mentioned resonant circuit is connected in series with the input end of the above-mentioned switched capacitor circuit, the output end of the above-mentioned resonant circuit is connected in parallel with the output end of the above-mentioned switched capacitor circuit, and the above-mentioned switched capacitor circuit includes N series-connected switched capacitor sub-circuits.

[0019] Another aspect of the present disclosure provides a train, comprising:

[0020] Such as the resonant converter mentioned above.

[0021] According to the embodiments of the present disclosure, by connecting the resonant circuit and the switched capacitor circuit in series at the input end and in parallel at the output end, the switched capacitor circuit can share the input voltage at the input end and output the same voltage as the resonant circuit at the output end, thereby forming a partial power processing structure, reducing power loss, and improving system efficiency. In addition, by controlling the working states of N switched capacitor sub-circuits in the switched capacitor circuit, the switched capacitor circuit can be used to bear a portion of the output voltage gain, thereby improving the voltage regulation range of the resonant converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0023] Figure 1 A block diagram of a switched capacitor based resonant converter according to an embodiment of the present disclosure is schematically shown;

[0024] Figure 2 A circuit diagram of a switched capacitor based resonant converter according to an embodiment of the present disclosure is schematically shown;

[0025] Figure 3 The flowchart of the switched capacitor-based resonant conversion method according to the embodiment of the present disclosure is schematically shown;

[0026] Figure 4 Schematically shows a gain characteristic curve of a switched capacitor based resonant converter according to an embodiment of the present disclosure; and

[0027] Figure 5 A circuit diagram of a train according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0029] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0030] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0031] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0032] In the embodiments of the present disclosure, the collection, updating, analysis, processing, use, transmission, provision, disclosure, storage, etc. of the data involved (for example, including but not limited to user personal information) are in compliance with the provisions of relevant laws and regulations, are used for legitimate purposes, and do not violate public order and good morals. In particular, necessary measures are taken for user personal information to prevent illegal access to user personal information data and maintain the security of user personal information, network security, and national security.

[0033] In the embodiments of the present disclosure, the user's authorization or consent is obtained before obtaining or collecting the user's personal information.

[0034] In the related art, when facing the requirement of wide-range voltage regulation, the switching frequency or duty cycle in the LLC resonant converter is adjusted to maintain a stable output, but this will lead to a decrease in efficiency and difficulty in the design of magnetic components.

[0035] In view of this, an embodiment of the present disclosure provides a resonant converter based on a switched capacitor, which resonant converter includes: a resonant circuit and a switched capacitor circuit; wherein the input end of the resonant circuit is connected in series with the input end of the switched capacitor circuit, the output end of the resonant circuit is connected in parallel with the output end of the switched capacitor circuit, the switched capacitor circuit includes N switched capacitor sub-circuits connected in series, and the switched capacitor circuit is used to control the working states of the N switched capacitor sub-circuits according to the input voltage of the resonant converter and the voltage gain range of the resonant circuit, so that the gain of the resonant circuit to the input voltage is maintained within the voltage gain range, and N is a positive integer.

[0036] Figure 1 A block diagram of a switched capacitor based resonant converter according to an embodiment of the present disclosure is schematically shown.

[0037] like Figure 1As shown, the switched capacitor based resonant converter 100 includes a resonant circuit 110 and a switched capacitor circuit 120 , wherein the switched capacitor circuit 120 includes N switched capacitor sub-circuits 121 connected in series.

[0038] Among them, the input end of the resonant circuit 110 is connected in series with the input end of the switched capacitor circuit 120, and the output end of the resonant circuit 110 is connected in parallel with the output end of the switched capacitor circuit 120. The switched capacitor circuit 120 is used to control the working state of N switched capacitor sub-circuits 121 according to the input voltage of the resonant converter 100 and the voltage gain range of the resonant circuit 110, so that the gain of the resonant circuit 110 to the input voltage is maintained within the voltage gain range, and N is a positive integer.

[0039] According to the embodiments of the present disclosure, by connecting the resonant circuit and the switched capacitor circuit in series at the input end and in parallel at the output end, the switched capacitor circuit can share the input voltage at the input end and output the same voltage as the resonant circuit at the output end, thereby forming a partial power processing structure, reducing power loss, and improving system efficiency. In addition, by controlling the working states of N switched capacitor sub-circuits in the switched capacitor circuit, the switched capacitor circuit can be used to bear a portion of the output voltage gain, thereby improving the voltage regulation range of the resonant converter.

[0040] Figure 2 A circuit diagram of a switched capacitor based resonant converter according to an embodiment of the present disclosure is schematically shown.

[0041] like Figure 2 As shown, the resonant circuit 210 includes a fifth switch tube Q5, a sixth switch tube Q6, a resonant inductor Lr, a resonant capacitor Cr, an excitation inductor Lm, a transformer Tx, a first diode D1, and a second diode D2. The switched capacitor circuit 220 includes a switched capacitor subcircuit (SC) 221, and the switched capacitor subcircuit 221 includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, and a switched capacitor Cs.

[0042] In the switched capacitor subcircuit, a first end of the first switch tube Q1 is connected to an input end of the switched capacitor Cs circuit, a second end of the first switch tube Q1 is connected to a first end of the second switch tube Q2 and a first end of the switched capacitor Cs, a first end of the third switch tube Q3 is connected to the input end of the switched capacitor circuit, a second end of the third switch tube Q3 is connected to a first end of the fourth switch tube Q4 and a second end of the switched capacitor Cs, and a second end of the second switch tube Q2 is connected to a second end of the fourth switch tube Q4.

[0043] Each switching capacitor sub-circuit is connected to a bus capacitor Cm, a first end of the bus capacitor Cm is connected to a first end of a first switching tube, a second end of the bus capacitor Cm is connected to a first end of a third switching tube, and the bus capacitor Cm is used to filter a voltage input to the switching capacitor sub-circuit, thereby maintaining the stability of the voltage input to the switching capacitor sub-circuit.

[0044] In the resonant circuit 210, a first end of the fifth switch tube Q5 is connected to the input end of the resonant circuit, a second end of the fifth switch tube Q5 is connected to the first end of the sixth switch tube Q6, a second end of the sixth switch tube Q6 is connected to the input end of the resonant circuit, a first end of the resonant inductor Lr is connected to the second end of the fifth switch tube Q5, a second end of the resonant inductor Lr is connected to the first end of the excitation inductor Lm, a first end of the resonant capacitor Cr is connected to the second end of the sixth switch tube Q6, a second end of the resonant capacitor Cr is connected to the second end of the excitation inductor Lm, the excitation inductor Lm is connected to the primary side of the transformer Tx, a first end of the secondary side of the transformer Tx is connected to the first end of the first diode D1, a second end of the secondary side of the transformer is connected to the first end of the second diode D2, a second end of the first diode D1 and a second end of the second diode D2 are grounded.

[0045] According to an embodiment of the present disclosure, by Figure 2 The circuit connection shown can keep the voltage gain range of the resonant converter of the embodiment of the present disclosure within a narrower range compared to the resonant converter in the related art, that is, achieve voltage regulation near its switching frequency and maintain its high efficiency characteristics.

[0046] According to an embodiment of the present disclosure, the operating states of the switched capacitor subcircuit include a first on state, a second on state and a short circuit state. In the first on state or the second on state, the voltage gain of the switched capacitor subcircuit is 1 / 2.

[0047] like Figure 2 As shown in , the switch capacitor subcircuit has a voltage gain of 1 / 2, wherein in the first conduction state, the first switch tube and the fourth switch tube are turned on, the second switch tube and the third switch tube are turned off, and the input voltage supplies power to the switch capacitor and the load. In the second conduction state, the second switch tube and the third switch tube are turned on, the first switch tube and the fourth switch tube are turned off, and the switch capacitor supplies power to the load. In the short-circuit state, the first switch tube and the second switch tube are turned on, and the third switch tube and the fourth switch tube are turned off. It can be understood that Figure 2 Only one level of switched capacitor subcircuit is illustrated in the figure, and the connections of other switched capacitor subcircuits not shown can refer to the circuit connections of the switched capacitor subcircuit shown, and the switched capacitor circuit can also be other circuit structures that can achieve a voltage gain of 1 / 2.

[0048] According to the embodiments of the present disclosure, the switched capacitor circuit can achieve power conversion only by relying on capacitors and switching devices without the need for magnetic components. Compared with the resonant converter in the related art, it can improve power density and reduce design difficulty.

[0049] According to an embodiment of the present disclosure, the half-bridge inverter circuit formed by the fifth switch tube and the sixth switch tube inverts the voltage input to the resonant circuit into a square wave voltage, and the square wave voltage generates a sinusoidal resonant current through a resonant network formed by a resonant inductor and a resonant capacitor. Due to the resonance characteristics, the sum of the voltages generated on the resonant inductor and the resonant capacitor is 0, so the square wave voltage is also applied to the excitation inductor, and the square wave voltage generates a triangular wave excitation current on the excitation inductor. The current component after subtracting the sinusoidal wave resonant current from the triangular wave excitation current is transmitted to the secondary side through the primary side of the transformer, and then supplies power to the load through a full-wave rectifier circuit formed by the first diode and the second diode.

[0050] According to an embodiment of the present disclosure, a switching capacitor circuit is used to determine M target switching capacitor subcircuits from N switching capacitor subcircuits based on an input voltage of a resonant converter and a voltage gain range of a resonant circuit, wherein the M target switching capacitor subcircuits are in a first conduction state or a second conduction state and NM non-target switching capacitor subcircuits are in a short-circuit state, so that the gain of the resonant circuit to the input voltage is maintained within a voltage gain range, and the voltage gain of the M target switching capacitor subcircuits is 1 / 2M, where M is a positive integer less than or equal to N.

[0051] According to an embodiment of the present disclosure, since the gain of the switching capacitor sub-circuit is 1 / 2, a switching capacitor sub-circuit can be added according to the voltage gain range of the resonant circuit when the voltage gain range of the resonant circuit is about to reach a critical value. The added switching capacitor sub-circuit can be called a target switching capacitor sub-circuit. Since the switching capacitor sub-circuits are connected in series, according to the number of target switching capacitor sub-circuits, the voltage gain of the switching capacitor circuit can be determined to be the sum of the voltage gains of M target switching capacitor sub-circuits, that is, 1 / 2M.

[0052] According to an embodiment of the present disclosure, the number of switched capacitor subcircuits is selected based on the input voltage of the resonant converter and the voltage gain range of the resonant circuit to keep the gain of the resonant circuit to the input voltage within the voltage gain range, thereby improving the gain flexibility of the resonant circuit to the input voltage.

[0053] According to the embodiments of the present disclosure, Figure 2 As shown, assuming the input voltage is , the voltage input to the resonant circuit is , the voltage input to the switched capacitor circuit is , the output voltage is , the gain of the resonant circuit is m:1, and the gain of the switched capacitor circuit is n:1, then the following relationship exists:

[0054] (1)

[0055] Then, the total voltage gain is:

[0056] (2)

[0057] On this basis, some power handling characteristics of the circuit structure are further analyzed. Since the two converter input terminals are connected in series, assuming that the input current is , the ratio of the power flowing in the resonant circuit to the switched capacitor circuit is:

[0058] (3)

[0059] That is, the ratio of the power flowing through the two is the ratio of their respective conversion ratios. Assuming that the conversion efficiency of the resonant circuit is , the conversion efficiency of the switched capacitor circuit is , then the total efficiency of the resonant converter can be calculated by the following formula:

[0060] (4)

[0061] Assumptions ,but The highest efficiency is achieved when the two efficiencies are equal, and vice versa. , regardless of the values ​​of m and n. Therefore, the physical meaning of partial power processing is to allow the high-efficiency converter to pass more power and the low-efficiency converter to pass less power, thereby reducing overall losses and improving system efficiency.

[0062] Figure 3 The flowchart of the switched capacitor-based resonant conversion method according to an embodiment of the present disclosure is schematically shown.

[0063] like Figure 3 As shown, the method is applied to the resonant converter of the embodiment of the present disclosure, wherein the resonant converter includes a resonant circuit and a switched capacitor circuit; the method includes operation S310.

[0064] In operation S310, the working states of N switched capacitor sub-circuits are controlled according to the input voltage of the resonant converter and the voltage gain range of the resonant circuit using a switched capacitor circuit so that the gain of the resonant circuit to the input voltage is maintained within the voltage gain range, wherein the input end of the resonant circuit is connected in series with the input end of the switched capacitor circuit, the output end of the resonant circuit is connected in parallel with the output end of the switched capacitor circuit, and the switched capacitor circuit includes N switched capacitor sub-circuits connected in series.

[0065] Figure 4 The gain characteristic curve of the switched capacitor based resonant converter according to the embodiment of the present disclosure is schematically shown.

[0066] like Figure 4 As shown, the horizontal axis is the input voltage range, the vertical axis is the gain adjustment range of the resonant circuit, n1, n2, n3, and n4 are discrete voltage gains of the switched capacitor circuit, and the gain of the resonant circuit is a continuous voltage gain between [m1, m2]. If there is no gain sharing of the switched capacitor circuit, the voltage gain range of the resonant circuit is [m1, m0]. Therefore, compared with the traditional resonant converter, the resonant converter provided by the present disclosure reduces the voltage gain range from [m1, m0] to [m1, m2], so that the resonant circuit can maintain high-efficiency operation near its resonant frequency, and reduces the difficulty of designing the magnetic components of the resonant converter.

[0067] According to the embodiments of the present disclosure, the switched capacitor circuit realizes power conversion only by relying on capacitors and switching devices without magnetic components, and has a high power density that cannot be matched by other types of converters. However, the traditional switched capacitor circuit cannot maintain high-efficiency output under continuous voltage regulation, while the switched capacitor circuit in the embodiments of the present disclosure can achieve discrete voltage gain, thereby obtaining higher conversion efficiency.

[0068] Figure 5 A circuit diagram of a train according to an embodiment of the present disclosure is schematically shown.

[0069] like Figure 5 As shown, the train 500 includes a resonant converter 510 .

[0070] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram may represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box may also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions. It can be understood by those skilled in the art that the features recorded in the various embodiments of the present disclosure can be combined and / or combined in a variety of ways, even if such a combination or combination is not explicitly recorded in the present disclosure. In particular, without departing from the spirit and teaching of the present disclosure, the features described in the various embodiments of the present disclosure may be combined and / or combined in a variety of ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0071] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A switched capacitor based resonant converter, comprising a resonant circuit and a switched capacitor circuit; in, The input end of the resonant circuit is connected in series with the input end of the switched capacitor circuit, the output end of the resonant circuit is connected in parallel with the output end of the switched capacitor circuit, the switched capacitor circuit includes N switched capacitor sub-circuits connected in series, the switched capacitor circuit is used to control the working states of the N switched capacitor sub-circuits according to the input voltage of the resonant converter and the voltage gain range of the resonant circuit, so that the gain of the resonant circuit to the input voltage is maintained within the voltage gain range, and N is a positive integer.

2. The resonant converter according to claim 1, in, The switch capacitor subcircuit includes a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a switch capacitor; The first end of the first switch tube is connected to the input end of the switch capacitor circuit, the second end of the first switch tube is connected to the first end of the second switch tube and the first end of the switch capacitor, the first end of the third switch tube is connected to the input end of the switch capacitor circuit, the second end of the third switch tube is connected to the first end of the fourth switch tube and the second end of the switch capacitor, and the second end of the second switch tube is connected to the second end of the fourth switch tube.

3. The resonant converter according to claim 2, in, Each of the switch capacitor sub-circuits is connected to a bus capacitor, a first end of the bus capacitor is connected to a first end of the first switch tube, a second end of the bus capacitor is connected to a first end of the third switch tube, and the bus capacitor is used to filter the voltage input to the switch capacitor sub-circuit.

4. The resonant converter according to claim 2 or 3, in, The working states of the switch capacitor subcircuit include a first conduction state, a second conduction state and a short circuit state. In the first conduction state or the second conduction state, the voltage gain of the switch capacitor subcircuit is 1 / 2.

5. The resonant converter according to claim 4, in, in, In the first on state, the first switch tube and the fourth switch tube are turned on, the second switch tube and the third switch tube are turned off, and the input voltage supplies power to the switch capacitor and the load; In the second on-state, the second switch tube and the third switch tube are turned on, the first switch tube and the fourth switch tube are turned off, and the switch capacitor supplies power to the load; In the short-circuit state, the first switch tube and the second switch tube are turned on, and the third switch tube and the fourth switch tube are turned off.

6. The resonant converter according to claim 4, in, The switch capacitor circuit is used to determine M target switch capacitor subcircuits from the N switch capacitor subcircuits according to the input voltage of the resonant converter and the voltage gain range of the resonant circuit, wherein the M target switch capacitor subcircuits are in the first conduction state or the second conduction state and NM non-target switch capacitor subcircuits are in a short-circuit state, so that the gain of the resonant circuit to the input voltage is maintained within the voltage gain range, and the voltage gain of the M target switch capacitor subcircuits is 1 / 2M, where M is a positive integer less than or equal to N.

7. The resonant converter according to any one of claims 1 to 3, in, The resonant circuit includes a fifth switch tube, a sixth switch tube, a resonant inductor, a resonant capacitor, an excitation inductor, a transformer, a first diode, and a second diode; The first end of the fifth switch tube is connected to the input end of the resonant circuit, the second end of the fifth switch tube is connected to the first end of the sixth switch tube, the second end of the sixth switch tube is connected to the input end of the resonant circuit, the first end of the resonant inductor is connected to the second end of the fifth switch tube, the second end of the resonant inductor is connected to the first end of the excitation inductor, the first end of the resonant capacitor is connected to the second end of the sixth switch tube, the second end of the resonant capacitor is connected to the second end of the excitation inductor, the excitation inductor is connected to the primary side of the transformer, the first end of the secondary side of the transformer is connected to the first end of the first diode, the second end of the secondary side of the transformer is connected to the first end of the second diode, and the second end of the first diode and the second end of the second diode are grounded.

8. The resonant converter according to claim 7, in, The half-bridge inverter circuit formed by the fifth switch tube and the sixth switch tube inverts the voltage input to the resonant circuit into a square wave voltage. The square wave voltage generates a sinusoidal resonant current through a resonant network formed by the resonant inductor and the resonant capacitor. The square wave voltage generates a triangular wave excitation current on the excitation inductor. The current component after subtracting the sinusoidal wave resonant current from the triangular wave excitation current is transmitted to the secondary side through the primary side of the transformer, and then supplies power to the load through the full-wave rectifier circuit formed by the first diode and the second diode.

9. A resonant conversion method based on switched capacitors, applied to the resonant converter as claimed in any one of claims 1 to 8, in, The resonant converter comprises a resonant circuit and a switched capacitor circuit; the method comprises: The switched capacitor circuit is used to control the working states of N switched capacitor sub-circuits according to the input voltage of the resonant converter and the voltage gain range of the resonant circuit, so that the gain of the resonant circuit to the input voltage is maintained within the voltage gain range, wherein the input end of the resonant circuit is connected in series with the input end of the switched capacitor circuit, the output end of the resonant circuit is connected in parallel with the output end of the switched capacitor circuit, and the switched capacitor circuit includes N switched capacitor sub-circuits connected in series.

10. A train, include: A resonant converter as claimed in any one of claims 1 to 8.

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