Resonant power converter and control method thereof

Abstract

The invention discloses a resonant power converter and a control method thereof. A switching circuit in the resonant power converter comprises at least one bridge arm, the at least one bridge arm is provided with an even number of resonant connection points connected with an even number of connection ports on the first side of a resonant network, and the first bridge arm is configured to operate in a first switching mode, a second switching mode and a third switching mode in a switching control period, the sum of the time when the first bridge arm operates in the second switching mode and the time when the first bridge arm operates in the third switching mode is equal to the time when the first bridge arm operates in the first switching mode, and when the first bridge arm operates in the first switching mode, the voltage provided by the even number of resonant connection points is a first voltage value; when the first bridge arm operates in the second switching mode and when the first bridge arm operates in the third switching mode, the voltages provided by the even number of resonant connection points are all second voltage values.

Description

Technical Field

[0001] This application relates to the field of power conversion circuit technology, and more specifically, to a resonant power converter and its control method. Background Technology

[0002] Resonant power converters introduce a resonant network composed of inductors, capacitors, and transformers, enabling switching devices to turn on / off under zero voltage or zero current conditions (soft switching). This significantly reduces switching losses and electromagnetic interference, thereby achieving high efficiency, high power density, and high frequency. They are particularly suitable for scenarios with stringent requirements for efficiency and size, such as server power supplies, electric vehicle charging, and photovoltaic inverters.

[0003] With the continuous maturation of high-voltage, high-performance switching devices (such as SiC devices), the voltage levels that resonant power converters can handle have significantly increased, leading to a growing demand for high-voltage applications. To meet this demand, most high-voltage resonant power converters on the market currently employ a two-stage cascaded structure (such as a front-stage BOOST + a rear-stage LLC). However, this approach suffers from problems such as a large number of switching devices and high cost. Therefore, quasi-single-stage resonant power converters, which combine high efficiency, high integration, and simplified topology, are becoming a key research focus in the field of high-voltage applications.

[0004] However, the quasi-single-stage resonant power converter in related technologies cannot simultaneously achieve adjustable boost ratio of the resonant network's processing voltage and maximize the utilization of the resonant network's processing voltage. Summary of the Invention

[0005] This application provides a resonant power converter and its control method. The various aspects involved in this application embodiment are described below.

[0006] In a first aspect, a resonant power converter is provided, comprising: a resonant network including a resonant circuit, wherein an even number of connection ports are provided on a first side of the resonant network; and a switching circuit including: at least one bridge arm, a DC bus capacitor, and at least one input inductor, wherein the DC bus capacitor is connected to a voltage source to form an input circuit, the bridge arm is connected in parallel with the input circuit, and the at least one bridge arm has an even number of resonant connection points, the even number of resonant connection points being connected to the even number of connection ports; wherein the at least one bridge arm includes a first bridge arm, the at least one input inductor includes a first input inductor of the first bridge arm, the first bridge arm includes a first switch, a second switch, and a third switch connected in series, and one end of the first input inductor is connected between the second switch and the third switch. The other end of the first input inductor is connected between the voltage source and the DC bus capacitor, and the voltage source is connected to both ends of the third switching transistor. The first bridge arm is configured to operate in a first switching mode, a second switching mode, and a third switching mode during the switching control cycle. The sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode. When the first bridge arm operates in the first switching mode, the voltage provided by the even-numbered resonant connection points is a first voltage value. When the first bridge arm operates in the second switching mode and when the first bridge arm operates in the third switching mode, the voltage provided by the even-numbered resonant connection points is a second voltage value.

[0007] Secondly, a control method for a resonant power converter is provided. The resonant power converter includes a resonant network and a switching circuit. The resonant network includes a resonant circuit, and an even number of connection ports are provided on a first side of the resonant network. The switching circuit includes at least one bridge arm, a DC bus capacitor, and at least one input inductor. The DC bus capacitor is connected to a voltage source to form an input circuit. The bridge arm is connected in parallel with the input circuit. An even number of resonant connection points are provided on the at least one bridge arm, and the even number of resonant connection points are connected to the even number of connection ports. The at least one bridge arm includes a first bridge arm. The at least one input inductor includes a first input inductor of the first bridge arm. The first bridge arm includes a first switch, a second switch, and a third switch connected in series. One end of the first input inductor is connected to the second switch and the third switch. Between the third switching transistors, the other end of the first input inductor is connected between the voltage source and the DC bus capacitor, and the voltage source is connected to both ends of the third switching transistor; the control method includes: controlling the first bridge arm to operate in a first switching mode, a second switching mode, and a third switching mode during a switching control cycle, and the sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode; wherein, when the first bridge arm operates in the first switching mode, the voltage provided by the even-numbered resonant connection points is a first voltage value; when the first bridge arm operates in the second switching mode, and when the first bridge arm operates in the third switching mode, the voltage provided by the even-numbered resonant connection points is a second voltage value.

[0008] Thirdly, a controller is provided for performing the method as described in the second aspect.

[0009] The resonant power converter provided in this application embodiment includes a switching circuit comprising at least one bridge arm, a DC bus capacitor, and at least one input inductor. The DC bus capacitor is connected to a voltage source to form an input circuit, and the input circuit is connected in parallel with each bridge arm. Since the at least one bridge arm has an even number of resonant connection points connected to an even number of connection ports on the first side of the resonant network, and the first bridge arm of the at least one bridge arm is configured to operate in a first switching mode, a second switching mode, and a third switching mode during a switching control cycle, and the sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode, wherein when the first bridge arm operates in the first switching mode, the voltage provided by the even number of resonant connection points is a first voltage value, and when the first bridge arm operates in the second switching mode and the third switching mode, the voltage provided by the even number of resonant connection points is a second voltage value. Based on this, the switching circuit in this embodiment can provide a square wave with a 50% duty cycle to the resonant network through an even number of resonant connection points. Since the time for the first bridge arm to operate in the second or third switching mode is variable, this variable time can be used to adjust the peak-to-peak value (i.e., the boost ratio is adjustable) of the square wave provided to the resonant network by the even number of resonant connection points. Thus, the switching circuit can provide a square wave with a 50% duty cycle and adjustable peak-to-peak value to the resonant network, thereby achieving both adjustable boost ratio of the resonant network's processing voltage and maximizing the utilization of the resonant network's processing voltage. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the structure of a resonant power converter in related technologies.

[0011] Figure 2 This is a schematic diagram of another resonant power converter in related technologies.

[0012] Figure 3 This is a schematic diagram of the structure of a resonant power converter provided in one embodiment of this application.

[0013] Figure 4 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0014] Figure 5 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0015] Figure 6 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0016] Figure 7 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0017] Figure 8 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0018] Figure 9 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0019] Figure 10 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0020] Figure 11 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0021] Figure 12 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0022] Figure 13 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0023] Figure 14 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0024] Figure 15 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0025] Figure 16 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0026] Figure 17 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0027] Figure 18 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0028] Figure 19 This is a schematic diagram of a switch drive signal for a first bridge arm provided in an embodiment of this application.

[0029] Figure 20 yes Figure 4 and Figure 7 A waveform diagram of Vab provided by a resonant power converter.

[0030] Figure 21 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0031] Figure 22This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0032] Figure 23 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0033] Figure 24 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0034] Figure 25 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0035] Figure 26 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0036] Figure 27 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0037] Figure 28 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0038] Figure 29 This is a schematic diagram of the structure of a resonant power converter provided in another embodiment of this application.

[0039] Figure 30 This is a schematic diagram of a unified topology provided in an embodiment of this application.

[0040] Figure 31 This is a flowchart illustrating the control method for a resonant power converter provided in an embodiment of this application. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application should fall within the scope of protection of the present application.

[0042] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0043] To meet the high-voltage application requirements of resonant power converters, most high-voltage resonant power converters on the market currently employ a two-stage cascaded structure (such as a front-end BOOST + a rear-end LLC). For ease of understanding, the following section will combine... Figure 1 This section provides a brief introduction to common resonant power converters that employ a two-stage cascaded structure.

[0044] See details Figure 1 The resonant power converter 100 includes a boost circuit 110 and a resonant converter circuit 120.

[0045] As an example, such as Figure 1 As shown, the boost circuit 110 is a BOOST circuit, specifically including a first bridge arm formed by a first switching transistor Q1 and a second switching transistor Q2 connected in series. One end of the input inductor Lg is connected to the midpoint of the first bridge arm, and the other end of the input inductor Lg is used to connect to the first connection terminal of the input voltage source. The first bridge arm is connected to the DC bus capacitor Cc, and one end of the first bridge arm (e.g., Figure 2 One of the terminals of Q2 is used to connect to the second terminal of the input voltage source. The boost circuit 110 is used to boost the voltage Vp provided by the input voltage source to the voltage U1 on the DC bus capacitor Cc.

[0046] The resonant converter circuit 120 includes a second bridge arm, a resonant circuit, a transformer T1, and a DC-DC converter circuit. The second bridge arm is formed by connecting a third switch Q3 and a fourth switch Q4 in series. The transformer T1 includes a primary winding and a secondary winding. The resonant circuit includes a resonant inductor L1 and a resonant capacitor C1, and is connected to the primary winding and / or the secondary winding. The transformer T1 and the resonant circuit together form a resonant network. The DC-DC converter circuit is used to transform the output voltage of the secondary winding of the transformer T1 to provide a transformed voltage externally. As an example, the DC-DC converter circuit is as follows: Figure 1 The H-bridge circuit shown includes a third bridge arm formed by connecting Qs1 and Qs2 in series and a fourth bridge arm formed by connecting Qs3 and Qs4 in series. The third and fourth bridge arms are connected in parallel, and the midpoints of the third and fourth bridge arms are respectively connected to the two ends of the secondary winding.

[0047] In this circuit, the voltage U1 on the DC bus capacitor Cc is chopped by Q3 and Q4 in the second bridge arm to form a square wave voltage Vab with a 50% duty cycle. Vab serves as the pre-processing voltage of the resonant converter circuit 120, or it can be understood as the pre-processing voltage of the resonant network, with its peak-to-peak square wave voltage being U1. U1 serves as the pre-input voltage of the resonant converter circuit 120, and its boost ratio can be flexibly adjusted in this topology. However, since this topology is a two-stage topology, it consumes a large number of switching transistors, resulting in problems such as a large number of switching devices, high cost, and difficulty in improving efficiency.

[0048] Based on this, quasi-single-stage resonant power converters, which combine high efficiency, high integration, and simplified topology, are becoming a research focus in high-voltage applications. As one possible implementation, a quasi-single-stage resonant power converter can be an isolated power converter based on two parallel boost circuits, integrating the functionality of the power converter formed by cascading the two-stage conversion circuits described above.

[0049] To make it easier to understand, the following will be combined with... Figure 2 This paper introduces quasi-single-stage resonant power converters in related technologies. For example... Figure 2 As shown, the resonant power converter 200 includes a first conversion circuit 210, a second conversion circuit 220, and a resonant network 230.

[0050] The resonant network 230 includes a transformer T2. The transformer T2 may include a primary winding and a secondary winding. A resonant circuit is connected to the primary winding and / or the secondary winding. Taking the primary winding as an example... Figure 2 As shown, the resonant circuit includes a resonant inductor L1 and a resonant capacitor C1. The resonant inductor L1 and the resonant capacitor C1, sometimes also including the leakage inductance or magnetic inductance of the transformer T2, together form a resonant cavity. The resonant cavity is used to generate a resonant current in response to the excitation of the switching bridge (the first and second bridge arms in the following text). This resonant current is coupled to the secondary side of the transformer T2 through the transformer T2, and after being rectified by the second conversion circuit 220, it is used as an output voltage source.

[0051] The first conversion circuit 210 is located on the primary side of transformer T2. The first conversion circuit 210 is used to connect to an input voltage source (e.g., an AC source or a DC source) and to convert the voltage V supplied by the input voltage source... p The conversion is performed. When the first conversion circuit 210 is connected to a DC source, the resonant power converter 200 is a DC-DC converter; when the first conversion circuit 210 is connected to an AC source, the resonant power converter 200 is an AC-DC converter. The first conversion circuit 210 may include: a first input inductor L. g1 Second input inductor L g2 DC bus capacitor C c And the first and second bridge arms connected in parallel.

[0052] Wherein, the first input inductor L g1 First terminal and second input inductor L g2The connection point of the first end forms the first connection point of the first side of the resonant power converter 200. The first connection point of the first side of the resonant power converter 200 is used to connect to the first output terminal of the input voltage source (e.g., the first output terminal of the voltage source is a positive output terminal or a negative output terminal). The midpoint S1 of the first bridge arm and the midpoint S2 of the second bridge arm are respectively connected to the first input inductor L. g1 The second terminal and the second input inductor L g2 The second end is connected, and the midpoint S1 of the first bridge arm and the midpoint S2 of the second bridge arm are also connected to the first and second ends of the primary winding of transformer T2, respectively. Therefore, it can be seen that the first input inductance L... g1 The midpoint S1 of the first bridge arm and the first end of the primary winding converge at the midpoint S1 of the first bridge arm, forming a current node; the second input inductor L... g2 The midpoint S2 of the second bridge arm and the second end of the primary winding converge at the midpoint S2 of the second bridge arm, forming a current node. The DC bus capacitor Cc is connected in parallel with both the first and second bridge arms, and one end of the first bridge arm and one end of the second bridge arm are used to connect to the second output terminal of the input voltage source. The second output terminal of the input voltage source has the opposite polarity to the input voltage source.

[0053] First input inductor L g1 Second input inductor L g2 The first and second bridge arms work together to convert the voltage Vp provided by the input voltage source into the DC bus capacitor C. c The voltage U1 on the circuit. The first bridge arm, the second bridge arm, the resonant circuit, and the primary side of transformer T2 are used to charge the DC bus capacitor C. c The voltage U1 is converted into the resonant current on the primary side of transformer T2, and the resonant current is coupled to the secondary side of the conversion circuit through the coupling between the primary and secondary sides of transformer T2. In some embodiments, the first or second bridge arm can be understood as a high-frequency bridge arm.

[0054] The second conversion circuit 220 includes a first terminal and a second terminal. The first terminal of the second conversion circuit 220 is connected to the secondary winding, and the second terminal of the second conversion circuit 220 forms a connection terminal on the second side of the power converter to be used as an output voltage source. The conversion of the voltage in the secondary winding by the second conversion circuit 220 may specifically include: rectifying and / or filtering the voltage in the secondary winding.

[0055] The first and second bridge arms are shared by the switching circuits in two parallel Boost circuits (including the first conversion circuit 210) and the switching circuits in the resonant conversion circuit (including the first and second bridge arms, transformer T2, resonant circuit, and the second conversion circuit 220). For example... Figure 2The quasi-single-stage resonant power converter shown has two common control methods, as detailed below.

[0056] The first control method involves complementary chopping of Q1 and Q2 with a 50% duty cycle, and complementary chopping of Q3 and Q4 with a 50% duty cycle. This boosts voltage U1 to twice Vp. Vab is a square wave with a peak-to-peak voltage of 2U1 and a 50% duty cycle. When using this method, the boost ratio is fixed at 50% duty cycle. In other words, the boost ratio of the voltage processed by the resonant network is fixed at 50% duty cycle and cannot be adjusted. Therefore, it is difficult to guarantee a wide range of voltage matching in the resonant converter circuit, affecting the efficiency of subsequent stages.

[0057] The second control method involves complementary chopping of Q1 and Q2 with a duty cycle not exceeding 50%, and complementary chopping of Q3 and Q4 with a duty cycle not exceeding 50%. Based on this, voltage U1 can be dynamically adjusted. However, when the duty cycle is not 50%, although U1 is adjustable, Vab is no longer a 50% square wave, but a three-level waveform. Since the fundamental component of the three-level waveform is smaller than that of an ideal square wave, the effective voltage received by the resonant network (i.e., the processing voltage U1 of the resonant network) decreases. Therefore, the utilization rate of the processing voltage U1 of the resonant network is reduced, resulting in a decrease in efficiency.

[0058] In summary, the quasi-single-stage resonant power converter in the related technologies cannot simultaneously achieve both adjustable boost ratio of the resonant network's processing voltage and maximize the utilization of the resonant network's processing voltage.

[0059] To address the above problems, this application provides a resonant power converter, which includes a resonant network and a switching circuit. The resonant network includes a resonant circuit with an even number of connection ports on a first side. The switching circuit includes at least one bridge arm, a DC bus capacitor, and at least one input inductor. The DC bus capacitor is connected to a voltage source to form an input circuit, and the input circuit is connected in parallel with each bridge arm. Since the at least one bridge arm has an even number of resonant connection points connected to the even number of connection ports on the first side of the resonant network, and the first bridge arm of the at least one bridge arm is configured to operate in a first switching mode, a second switching mode, and a third switching mode during a switching control cycle, the sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode. When the first bridge arm operates in the first switching mode, the voltage provided by the even number of resonant connection points is a first voltage value; when the first bridge arm operates in the second switching mode and when the first bridge arm operates in the third switching mode, the voltage provided by the even number of resonant connection points is a second voltage value. Based on this, the switching circuit in this embodiment can provide a square wave with a 50% duty cycle to the resonant network through an even number of resonant connection points. Since the time for the first bridge arm to operate in the second or third switching mode is variable, this variable time can be used to adjust the peak-to-peak value (i.e., the boost ratio is adjustable) of the square wave provided to the resonant network by the even number of resonant connection points. Thus, the switching circuit can provide a square wave with a 50% duty cycle and adjustable peak-to-peak value to the resonant network, thereby achieving both adjustable boost ratio of the resonant network's processing voltage and maximizing the utilization of the resonant network's processing voltage.

[0060] To facilitate understanding of this application, the following is combined with... Figures 3-29 The resonant power converter provided in this application embodiment will be described in more detail. It should be noted that this application embodiment does not specifically limit the type of resonant power converter. For example, the resonant power converter can be one of the following: a resonant DC-DC converter, a resonant AC-DC converter (or rectifier), a resonant DC-AC converter (or inverter), or a resonant bidirectional DC-AC converter (e.g., a power conversion system, PCS). The resonant bidirectional DC-AC converter can convert both DC and AC power.

[0061] like Figures 3-29 As shown, the resonant power converter 300 provided in this embodiment includes a resonant network 310 and a switching circuit 320.

[0062] The resonant network 310 has a first side and a second side, wherein when the first side is the input side, the second side is the output side, and when the first side is the output side, the second side is the input side. The resonant network 310 may include a resonant circuit, and the first side of the resonant network has an even number of connection ports. In some embodiments, such as... Figure 4 As shown, an even number of connection ports are also provided on the second side of the resonant network. The resonant circuit is used to select, amplify, or transport signals or energy at a specific frequency. This application does not specifically limit the structure of the resonant circuit. For example, the resonant circuit may include at least one inductor and at least one capacitor. In some embodiments, the at least one capacitor may be a parasitic capacitance. For example, when the resonant network also includes a transformer, the parasitic capacitance of the transformer windings may form a resonant circuit together with at least one inductor. As an example, the resonant circuit may include, for example... Figure 2 The inductors L1 and L2 and capacitor C1 are shown.

[0063] An even number of connection ports are used to couple the resonant network 310 to the switching circuit 320. Specifically, an even number of connection ports on the first side are used to couple the first side of the resonant network 310 to the switching circuit 320, and an even number of connection ports on the second side are used to couple the second side of the resonant network to another switching circuit 330.

[0064] As an example, such as Figure 3 As shown, one end of inductor L1 is connected in series with one end of capacitor C1, and the other ends of inductor L1 and capacitor C1 together form an even number of connection ports on the first side of resonant network 310. One end of inductor L2 is connected to the connection point of inductor L1 and capacitor C1, and the other ends of inductor L2 and inductor L1 together form an even number of connection ports on the second side of resonant network 310.

[0065] In some embodiments, the switching circuit 320 is the pre-amplifier circuit of the resonant network 310. In this case, the even-numbered connection ports on the first side can be understood as the input ports of the resonant network 310, which is used to resonate and transform the output voltage of the switching circuit 320. As an example, such as Figure 4 As shown, the resonant network also includes a transformer T3. The even-numbered connection ports on the first side are the ports of the primary winding of the transformer T3, and the even-numbered connection ports on the second side are the ports of the secondary winding of the transformer T3.

[0066] In other embodiments, the switching circuit 320 is a subsequent circuit of the resonant network 310. In this case, the even-numbered connection ports on the first side can be understood as the output ports of the resonant network 310, which is used to resonate and transform the input voltage of the switching circuit 320. As an example, such as Figure 29As shown, the resonant network also includes a transformer T3. The even-numbered connection ports on the first side are the ports of the secondary winding of the transformer T3, and the even-numbered connection ports on the second side are the ports of the primary winding of the transformer T3.

[0067] As a concrete example, such as Figure 4 As shown, the resonant network 310 is similar to the resonant network 230 described above. Specifically, the resonant network 310 may include a transformer T3 and a resonant circuit. The transformer T3 may include a primary winding and a secondary winding. A resonant circuit is connected to the primary winding and / or the secondary winding. Taking the primary winding as an example, as... Figure 3 As shown, the resonant circuit includes a resonant inductor L1 and a resonant capacitor C1. The resonant inductor L1 and resonant capacitor C1, and sometimes also include the leakage inductance or magnetic inductance of the transformer T3, together form a resonant cavity. The resonant cavity is used to generate a resonant current in response to the excitation of the switching circuit 320. This resonant current is coupled to the secondary side of the transformer T3 through the transformer T3, and after rectification by the conversion circuit connected to the secondary side of the resonant network 310, it is used as an output voltage source.

[0068] The switching circuit 320 includes at least one bridge arm, at least one input inductor, and a DC bus capacitor Cc. This application embodiment does not specifically limit the number of bridge arms in the at least one bridge arm included in the switching circuit. For example, such as... Figures 3-19 As shown, at least one bridge arm is a single bridge arm, meaning the switching circuit is formed by a single-bridge-arm topology. For example, as... Figures 23-28 As shown, at least one bridge arm is a two-arm bridge, that is, the switching circuit is formed by a dual-bridge-arm topology.

[0069] The DC bus capacitor Cc is connected to the voltage source to form an input circuit, and each of at least one bridge arm is connected in parallel with the input circuit. This application does not specifically limit the connection method between the DC bus capacitor and the voltage source. For example, when there is one DC bus capacitor, it can be connected in series with the voltage source. Similarly, when there are two DC bus capacitors, the voltage source can be connected in series with both DC bus capacitors. As an example, two DC bus capacitors can be connected in series, followed by a voltage source. As another example, the voltage source can be connected in series between the two DC bus capacitors. Furthermore, when there are three DC bus capacitors, they can be connected in series, and the voltage source can be connected in parallel to any one of these three DC bus capacitors.

[0070] The DC bus capacitor Cc is connected to the voltage source to form an input circuit. It can be connected to at least one bridge arm through at least one input inductor. At least one input inductor acts as a volt-second balancing element. The integral value of the voltage across its terminals is 0 during one switching cycle of the corresponding bridge arm, so as to ensure that the magnetic core operates in the linear region.

[0071] In this embodiment, at least one bridge arm is used both to boost the voltage Vp of the voltage source to the sum of the voltage Uc and Vp on the DC bus capacitor Cc, and to excite the voltage at the even-numbered connection ports on the first side of the resonant network using Uc+Vp. In this embodiment, each of the at least one bridge arm is used to connect to the DC bus capacitor Cc, and at least one bridge arm is provided with an even-numbered resonant connection point for connecting to the even-numbered connection ports on the first side of the resonant network.

[0072] A resonant connection point is an electrical node in at least one bridge arm that is directly coupled to the first side of the resonant network. An even number of resonant connection points are used to provide the resonant excitation voltage (or the processing voltage of the resonant network, such as Vab or Vcd) to the first side of the resonant network. For example, when an even number of resonant connection points are connected to the primary winding, they provide the processing voltage Vab to the primary winding. Similarly, when an even number of resonant connection points are connected to the secondary winding, they provide the processing voltage Vcd to the secondary winding.

[0073] An even number of resonant connection points can be understood as at least one pair of resonant connection points. In some embodiments, such as 3- Figure 19 , Figures 23-24 as well as Figures 27-28 As shown, an even number of resonant connection points constitutes two resonant connection points, that is, one resonant connection point pair. In other embodiments, such as... Figures 25-26 As shown, an even number of resonant connection points constitutes 4 resonant connection points, that is, 2 resonant connection point pairs.

[0074] In this embodiment, regardless of whether at least one bridge arm is a single bridge arm or a double bridge arm, at least one bridge arm includes a first bridge arm and at least one input inductor includes the first input inductor Lg1 of the first bridge arm. The first bridge arm includes a first switch Q1, a second switch Q2, and a third switch Q3 connected in series. The first input inductor Lg1 of the first bridge arm is connected between the second and third switches, and the other end of the first input inductor Lg1 of the first bridge arm is connected between a voltage source and a DC bus capacitor Cc. The voltage source is connected across the third switch Q3, and one end of the voltage source is connected to one end of the third switch Q3 through the first input inductor Lg1 of the first bridge arm. The input inductor Lg1 of the first bridge arm acts as a volt-second balancing element, and the integral value of its voltage over one switching cycle of the first bridge arm is 0.

[0075] In this embodiment, the first bridge arm is configured to operate in a first switching mode, a second switching mode, and a third switching mode within a switching control cycle T. The sum of the time T2 during which the first bridge arm operates in the second switching mode and the time T3 during which the first bridge arm operates in the third switching mode is equal to the time T1 during which the first bridge arm operates in the first switching mode. Specifically, when the first bridge arm operates in the first switching mode, the voltage provided by the even-numbered resonant connection points is a first voltage value; when the first bridge arm operates in the second switching mode, the voltage provided by the even-numbered resonant connection points is a second voltage value; and when the first bridge arm operates in the third switching mode, the voltage provided by the even-numbered resonant connection points is still the second voltage value. One of the first voltage value and the second voltage value is 0, and the other is a non-zero constant value. For example, when the first voltage value is 0, the second voltage value is a non-zero constant value. Similarly, when the first voltage value is a non-zero constant value, the second voltage value is 0.

[0076] In this embodiment, a switching mode can refer to a combination of the on and off states of three switches in a bridge arm over a period of time, and the first, second, and third switching modes are different. Each switching mode corresponds to a fixed combination of switch drive signals. This embodiment does not specifically limit the specific switching state combinations corresponding to the first, second, and third switching modes, as this is related to the topology of the bridge arm and the location of the even number of resonant connection points, as detailed below.

[0077] Based on this, we know that T2 + T3 = T1 = T / 2, meaning that the duty cycle of the first switching mode is 50%, and the sum of the duty cycles of the second and third switching modes is 50%. Furthermore, the voltage provided by the even-numbered resonant connection points in the first switching mode is a first voltage value, while the voltages provided by the even-numbered resonant connection points in the second and third switching modes are second voltage values. Therefore, in the switching circuit provided in this embodiment, the even-numbered resonant connection points on at least one bridge arm of 320 can be used to provide a square wave with a 50% duty cycle to the first side of the resonant network.

[0078] This application does not specifically limit the duty cycle of the second switching mode or the third switching mode, as long as the sum of the duty cycles of the second and third switching modes is 50%. Based on this, it can be seen that the duty cycle of the second switching mode (or time ratio (see Table 1 or Table 2 below)) or the duty cycle of the third switching mode is adjustable. For example, if the duty cycle of the third switching mode is set to D, then the duty cycle of the second switching mode is 0.5-D. Based on the calculation principle of the cumulative volt-second value of the input inductor, it can be seen that the adjustable duty cycle is related to the non-zero constant value of the first and second voltage values ​​(that is, the peak-to-peak value of the square wave with a duty cycle of 50%). Therefore, the duty cycle of the third switching mode or the duty cycle of the second switching mode can be used to adjust the peak-to-peak value of the square wave with a duty cycle of 50% provided by the even number of resonant connection points, thereby realizing the provision of a square wave with a 50% duty cycle and adjustable peak-to-peak value to the resonant network. In other words, it realizes both the adjustable boost ratio of the resonant network's processing voltage and the maximization of the utilization of the resonant network's processing voltage.

[0079] By implementing the embodiments of this application, not only can a square wave with a 50% duty cycle be provided to the first side of the resonant network through the switching circuit 320, but the peak-to-peak value of the square wave is also adjustable. Therefore, the quasi-single-stage resonant power converter 300 provided by the embodiments of this application takes into account both the adjustable boost ratio of the processing voltage on the first side of the resonant network and the maximization of the processing voltage on the first side of the resonant network.

[0080] As mentioned earlier, at least one bridge arm can be a single bridge arm. For ease of understanding, the following is an example illustration of a topology where at least one bridge arm contains only a single bridge arm. Figures 3-19 As shown, at least one bridge arm includes only the first bridge arm. The first bridge arm includes a first switch Q1, a second switch Q2, and a third switch Q3 connected in series. As mentioned earlier, the two ends of the third switch Q3 are used to connect a voltage source. This application embodiment does not specifically limit the position of the third switch Q3 in the first bridge arm. It should be noted that the following description uses a voltage source as an input voltage source, but this application embodiment does not limit the voltage source to only an input voltage source. The voltage source can also be an output voltage source.

[0081] For example, such as Figures 3-15 As shown, the third switch Q3 is the end switch of the first bridge arm. In this case, the middle switch of the first bridge arm can be the second switch Q2, that is, the second switch Q2 is located between the third switch Q3 and the first switch Q1, and the first switch Q1 is the other end switch of the first bridge arm. As an example, such as... Figures 7-9 and Figures 13-15As shown, the third switch Q3 can be the upper switch of the first bridge arm, and the first switch Q1 is the lower switch of the first bridge arm. Based on this, the first input inductor Lg1 of the first bridge arm is used to connect the negative output terminal of the input voltage source and the third switch. As another example, such as... Figures 3-6 and Figures 10-12 As shown, the third switch Q3 can be the lower end switch of the first bridge arm, and the first switch Q1 is the upper end switch of the first bridge arm. Based on this, the first input inductor Lg1 of the first bridge arm is used to connect the positive output terminal of the input voltage source and the third switch.

[0082] For example, such as Figures 16-19 As shown, the third switch Q3 is the middle switch of the first bridge arm, that is, the third switch Q3 is located between the first switch Q1 and the second switch Q2. The first switch Q1 is the switch at one end of the first bridge arm, and the second switch Q2 is the switch at the other end of the first bridge arm. The first switch Q1 is the switch that participates in forming an even number of resonant connection points. As an example, such as... Figure 16 and Figure 18 As shown, the first switch Q1 is the upper end switch of the first bridge arm, and the second switch Q2 is the lower end switch of the first bridge arm. As another example, such as... Figure 17 and Figure 19 As shown, the first switch Q1 is the lower end switch of the first bridge arm, and the second switch Q2 is the upper end switch of the first bridge arm.

[0083] The even-numbered connection ports on the first side of the resonant network include a first connection port and a second connection port (e.g., ...). Figure 3 The two ends of the series circuit of L1 and C1, or, Figure 4 The two ends of the primary winding in the middle, or, Figure 29 (The two ends of the winding in the appendix). Based on this, when at least one bridge arm contains only the first bridge arm, the even number of resonant connection points include the first resonant connection point S1 and the second resonant connection point S2 located on the first bridge arm, and the first resonant connection point S1 and the second resonant connection point S2 are respectively connected to the first connection port and the second connection port, and the voltage provided by the even number of resonant connection points is the voltage between the first resonant connection point S1 and the second resonant connection point S2.

[0084] This application does not specifically limit the exact locations of the first and second resonant points on the first bridge arm, as long as the voltage between the first resonant connection point S1 and the second resonant connection point S2 on the first bridge arm can be used as the processing voltage for the even number of connection ports, including the first and second connection ports, on the first side of the resonant network. It should be noted that the specific locations of the first and second resonant points on the first bridge arm are related to the topology of the first bridge arm and the placement of at least one input inductor and DC bus capacitor Cc. The specific locations of the first and second resonant points on the first bridge arm will be exemplified below with reference to different topologies.

[0085] By setting at least one bridge arm in the switching circuit as the first bridge arm, a square wave with a 50% duty cycle can be provided to the first and second connection ports on the first side of the resonant network through the switching circuit with fewer switching transistors. Moreover, the peak-to-peak value of the square wave is adjustable. Based on this, the quasi-single-stage resonant power converter 300 provided in this application embodiment can not only take into account the adjustable boost ratio of the processing voltage of the resonant network and the maximum utilization of the processing voltage of the resonant network, but also achieve the minimization of the overall cost of the quasi-single-stage resonant power converter 300.

[0086] In some embodiments, such as Figures 3-9 As shown, when the third switch Q3 is the end switch of the first bridge arm, the DC bus capacitor Cc is one, and at least one input inductor is also only the first input inductor Lg1 of the first bridge arm. Specifically, as... Figures 3-9 As shown, the first input inductor Lg1 of the first bridge arm is connected between the second switch Q2 and the third switch Q3, and the other end of the first input inductor Lg1 of the first bridge arm is connected between the voltage source and the DC bus capacitor Cc. This arrangement allows for a smaller number of capacitors and input inductors, thereby further reducing the number of components in the quasi-single-stage resonant power converter 300 and simplifying its layout.

[0087] In other embodiments, such as Figures 10-15 As shown, when the third switch Q3 is the end switch of the first bridge arm, there are two DC bus capacitors (i.e., the first DC bus capacitor Cc1 and the second DC bus capacitor Cc2), and at least one input inductor is also two (i.e., the first input inductor Lg1 and the second input inductor Lg2 of the first bridge arm). Specifically, as... Figures 10-15As shown, the DC bus capacitor includes a first DC bus capacitor Cc1 and a second DC bus capacitor Cc2 connected in series. The first DC bus capacitor Cc1 is connected across the first switch Q1, and the second DC bus capacitor Cc2 is connected across the second switch Q2. At least one input inductor includes a first input inductor Lg1 and a second input inductor Lg2 of the first bridge arm. One end of the first input inductor Lg1 of the first bridge arm is connected between the second switch Q2 and the third switch Q3, and the other end of the first input inductor Lg1 is connected between the voltage source and the second DC bus capacitor Cc2. One end of the second input inductor Lg2 of the first bridge arm is connected between the first switch Q1 and the second switch Q2, and the other end of the second input inductor Lg2 of the first bridge arm is connected between the first DC bus capacitor Cc1 and the second DC bus capacitor Cc2. Although this configuration increases the number of DC bus capacitors and input inductors, the voltage borne by the DC bus capacitors and input inductors can be reduced, which is beneficial for selecting lower-cost DC bus capacitors and inductors, thereby further reducing the cost of the quasi-single-stage resonant power converter 300.

[0088] It should be understood that when the third switch Q3 is the intermediate switch of the first bridge arm (i.e., the third switch Q3 is located between the first switch Q1 and the second switch Q2), there can be two DC bus capacitors, and at least one input inductor can also be two. As an example, such as... Figures 16-19 As shown, the DC bus capacitor includes a first DC bus capacitor Cc1 and a second DC bus capacitor Cc2 located at both ends of the voltage source. The first DC bus capacitor Cc1 is connected across the first switch Q1, and the second DC bus capacitor Cc2 is connected across the second switch Q2. At least one input inductor includes a first input inductor Lg1 and a second input inductor Lg2 of the first bridge arm. One end of the first input inductor Lg1 is connected between the second switch Q2 and the third switch Q3, and the other end is connected between the voltage source and the second DC bus capacitor Cc2. One end of the second input inductor Lg2 is connected between the first switch Q1 and the third switch Q3, and the other end is connected between the first DC bus capacitor Cc1 and the voltage source. Although this configuration increases the number of DC bus capacitors and input inductors, the voltage borne by the DC bus capacitors and input inductors can be reduced, which is beneficial for selecting lower-cost DC bus capacitors and inductors, thereby further reducing the cost of the quasi-single-stage resonant power converter 300.

[0089] When at least one bridge arm includes only the first bridge arm, the specific switching state combinations corresponding to the first switching mode, the second switching mode, and the third switching mode of the first bridge arm are related to the topology of the first bridge arm and the setting positions of the even number of resonant connection points.

[0090] As an example, such as Figure 3 , Figure 4 and Figure 7 As shown, the second switch Q2 is located between the first switch Q1 and the third switch Q3, and the first resonant connection point S1 and the second resonant connection point S2 are the two ends of the second switch Q2. The first bridge arm is specifically configured to operate in a first switching mode, a second switching mode, and a third switching mode during the switching control cycle, and the sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode. Specifically, when the first bridge arm operates in the first switching mode, the second switch Q2 is off, and both the first switch Q1 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc + Vp. When the first bridge arm operates in the second switching mode, the first switch Q1 is off, and both the second switch Q2 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first switch Q1 and the second switch Q2 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. The relationship between the above three switching modes and their operating times can be found in Table 1.

[0091] Table 1 For the switching mode configuration in Table 1, the switching drive signal of the first bridge arm can be as follows: Figure 20 As shown. See details. Figure 20 Its switching mode (or switching state) is as follows: first, the first switching mode; then, the third switching mode; then, the second switching mode, and so on. It should be noted that the order of the switching modes can be other than this, without special restrictions, as long as the time ratio meets the requirements. For example, it could also be the first switching mode, then the second switching mode, then the third switching mode. Or, it could be the second switching mode, then the third switching mode, then the first switching mode. Regarding the switching mode configurations in Table 1, for example... Figure 3 , Figure 4 and Figure 7 The waveform of the voltage (Vab) between the first resonant connection point S1 and the second resonant connection point S2 is shown below. Figure 21As shown. See details. Figure 21 Vab is a square wave with a 50% duty cycle and its peak-to-peak voltage is Uc+Vp.

[0092] As mentioned earlier, the duty cycle of the third switching mode or the duty cycle of the second switching mode can be used to adjust the peak-to-peak value of a square wave with a 50% duty cycle provided by an even number of resonant connection points. The following example, using the duty cycle D of the third switching mode, illustrates the relationship between the duty cycle D of the third switching mode and the peak-to-peak value of a square wave with a 50% duty cycle provided by an even number of resonant connection points (i.e., the aforementioned non-zero constant value, such as Uc+Vp or Uc1+Uc2+Vp).

[0093] To Figure 3 The calculation principle analysis of the cumulative volt-second value of the input inductance Lg of the first bridge arm shows that the voltage Uc, the duty cycle D of the third switching mode, and the input voltage source Vp satisfy the following relationship.

[0094] .

[0095] From this, we can deduce that: .

[0096] Therefore, controlling the value of D controls the boost ratio, which in turn controls the peak-to-peak value of the square wave with a 50% duty cycle provided by the even number of resonant connection points. Specifically, the smaller D is, the lower the peak-to-peak value of the square wave with a 50% duty cycle provided by the even number of resonant connection points. The larger.

[0097] Additionally, it should be noted that for Figure 10 and Figure 13 The first bridge arm shown is configured in the same way as the resonant connection point, the only difference being that... Figure 10 and Figure 13 As shown in the first bridge arm, when the first bridge arm operates in the first switching mode, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 can still be a square wave with a peak-to-peak voltage of non-zero constant value Uc1+Uc2+Vp and a duty cycle of 50%. Uc1 and Uc2 satisfy the following relationships respectively.

[0098] Based on the above two formulas, we can deduce that: .

[0099] As another example, such as Figure 5 and Figure 8As shown, the second switch Q2 is located between the first switch Q1 and the third switch Q3, and the first resonant connection point S1 and the second resonant connection point S2 are the two ends of the first switch Q1. The first bridge arm is specifically configured to operate in a first switching mode, a second switching mode, and a third switching mode during the switching control cycle, and the sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode. Specifically, when the first bridge arm operates in the first switching mode, the first switch Q1 is off, and both the second switch Q2 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc + Vp. When the first bridge arm operates in the second switching mode, the second switch Q2 is off, and both the first switch Q1 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first switch Q1 and the second switch Q2 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. The relationship between the three switching modes and their operating times can be found in Table 2. Additionally, it should be noted that for... Figure 11 and Figure 14 The first bridge arm shown is configured in the same way as the resonant connection point, the only difference being that... Figure 11 and Figure 14 The first bridge arm shown is in the first switching mode. The voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc1+Uc2+Vp.

[0100] Table 2 As yet another example, such as Figure 6 and Figure 9As shown, the second switch Q2 is located between the first switch Q1 and the third switch Q3. The first resonant connection point S1 and the second resonant connection point S2 are the two ends of the series circuit formed by the second switch Q2 and the third switch Q3. The first bridge arm is specifically configured to operate in the first switching mode, the second switching mode, and the third switching mode during the switching control cycle, and the sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode. Specifically, when the first bridge arm operates in the first switching mode, the first switch Q1 is off, and both the second switch Q2 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. When the first bridge arm operates in the second switching mode, the second switch Q2 is off, and both the first switch Q1 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc + Vp. When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first switch Q1 and the second switch Q2 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc + Vp. The relationship between the above three switching modes and their operating times can be found in Table 2. In addition, it should be noted that for Figure 12 and Figure 15 The first bridge arm shown is configured in the same way as the resonant connection point, the only difference being that... Figure 12 and Figure 15 The first bridge arm shown is operated in the second or third switching mode. When the first bridge arm is in the second or third switching mode, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc1+Uc2+Vp.

[0101] As yet another example, such as Figure 16 and Figure 17As shown, the third switch Q3 is located between the first switch Q1 and the second switch Q2. The first resonant connection point S1 and the second resonant connection point S2 are the two ends of the first switch Q1. The first bridge arm is specifically configured to operate in a first switching mode, a second switching mode, and a third switching mode during the switching control cycle, and the sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode. Specifically, when the first bridge arm operates in the first switching mode, the first switch Q1 is off, and both the second switch Q2 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc1 + Uc2 + Vp. When the first bridge arm operates in the second switching mode, the second switch Q2 is off, and both the first switch Q1 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first switch Q1 and the second switch Q2 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. The relationship between the above three switching modes and their operating times can be found in Table 2.

[0102] As yet another example, such as Figure 18 and Figure 19 As shown, the third switch Q3 is located between the first switch Q1 and the second switch Q2. The first resonant connection point S1 and the second resonant connection point S2 are the two ends of the series circuit formed by the first switch Q1 and the third switch. The first bridge arm is specifically configured to operate in the first switch mode, the second switch mode, and the third switch mode during the switch control cycle, and the sum of the time the first bridge arm operates in the second switch mode and the time the first bridge arm operates in the third switch mode is equal to the time the first bridge arm operates in the first switch mode. Specifically, when the first bridge arm operates in the first switch mode, the second switch Q2 is off, and both the first switch Q1 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is 0. When the first bridge arm operates in the second switch mode, the first switch Q1 is off, and both the second switch Q2 and the third switch Q3 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc1 + Uc2 + Vp. When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first switch Q1 and the second switch Q2 are on. At this time, the voltage Vab between the first resonant connection point S1 and the second resonant connection point S2 is a non-zero constant value Uc1+Uc2+Vp. The relationship between the above three switching modes and their operating times can be found in Table 1.

[0103] As mentioned earlier, the third switch Q3 is connected across the voltage source. In some embodiments, such as Figure 22 As shown, a filter capacitor C and a filter can also be connected between the third switch Q3 and the voltage source. The filter capacitor C is connected across the third switch Q3 and is also connected to the filter, which is connected to the input voltage source Vp (or the output voltage source). By setting the filter capacitor and the filter, current ripple can be filtered out to improve the reliability of the resonant power converter 300. Of course, Figure 22 For example only, when the position of the third switch Q3 is... Figure 22 At the same time, the filter capacitor and filter can also be changed to correspond to the position of the third switch Q3, as long as the filter capacitor C and the filter are connected between the third switch Q3 and the voltage source.

[0104] As mentioned earlier, at least one bridge arm can be two bridge arms. For ease of understanding, the following is an illustrative example of a topology where at least one bridge arm comprises two bridge arms. Figures 23-28 As shown, at least one bridge arm includes a first bridge arm and a second bridge arm. The first bridge arm includes a first switch Q1, a second switch Q2, and a third switch Q3 connected in series. The connection relationship of the first switch Q1, the second switch Q2, and the third switch Q3 is as described above. The second bridge arm includes a fourth switch Q4, a fifth switch Q5, and a sixth switch Q6 connected in series, with the sixth switch Q6 connected across the voltage source.

[0105] In this embodiment, the topologies of the first and second bridge arms are similar. The first switch Q1 in the first bridge arm and the fourth switch Q4 in the second bridge arm have the same position and function. The second switch Q2 in the first bridge arm and the fifth switch Q5 in the second bridge arm have the same position and function. The third switch Q3 in the first bridge arm and the sixth switch Q6 in the second bridge arm have the same position and function. Therefore, the topology of the second bridge arm can be referred to the description of the topology of the first bridge arm above, and will not be repeated here.

[0106] For at least one bridge arm including a first bridge arm and a second bridge arm, the even number of resonant connection points on the at least one bridge arm may include resonant connection points located on the first bridge arm and resonant connection points located on the second bridge arm. The first bridge arm is configured to operate in a first switching mode, a second switching mode, and a third switching mode during the switching control cycle. The second bridge arm is configured to operate in the same switching mode as the first bridge arm, and the drive signals of each switch in the second bridge arm have a 180° phase difference relative to the drive signals of each switch in the first bridge arm. That is, the second bridge arm is still configured to operate in the first switching mode, the second switching mode, and the third switching mode during the switching control cycle, except that the drive signals of each switch in the second bridge arm have a 180° phase difference compared to the drive signals of each switch in the first bridge arm.

[0107] By configuring at least one bridge arm in the switching circuit 320 as a first bridge arm and a second bridge arm connected in parallel, with the drive signals of the first bridge arm and the second bridge arm having a 180° phase difference, it is possible to provide a square wave with a 50% duty cycle to an even number of connection ports on the first side of the resonant network 310 through the switching circuit 320. The peak-to-peak value of this square wave is adjustable. Simultaneously, it is possible to increase output power and suppress input current ripple based on interleaving control. Based on this, by implementing the embodiments of this application, the quasi-single-stage resonant power converter 300 not only achieves adjustable boost ratio of the resonant network's processing voltage and maximizes the utilization of the resonant network's processing voltage, but also possesses higher power output capability and higher reliability.

[0108] In some embodiments, if at least one bridge arm in the switching circuit 320 includes both a first bridge arm and a second bridge arm, at least one input inductor in the switching circuit 320 may include only the first input inductor Lg1 of the first bridge arm, and its connection method can be found above. By using only one input inductor to extract the power current on the bridge arm to participate in resonance, the overall cost of the power converter can be reduced.

[0109] In other embodiments, such as Figures 23-28 As shown, at least one input inductor may include the first input inductor Lg1 of the first bridge arm and the first input inductor Lj1 of the second bridge arm. The connection method of the first input inductor Lg1 of the first bridge arm is described above. One end of the first input inductor Lj1 of the second bridge arm is connected between the fifth switch Q5 and the sixth switch Q6, and the other end is connected between the DC bus capacitor Cc and the voltage source. By using the first input inductors Lg1 and Lj1 of the first and second bridge arms respectively to extract the power current from the first and second bridge arms and participate in resonance, current ripple can be reduced, thereby reducing the overall loss of the power converter.

[0110] As mentioned earlier, when at least one bridge arm includes a first bridge arm and a second bridge arm, the even number of resonant connection points includes resonant connection points located on the first bridge arm and resonant connection points located on the second bridge arm. Based on this, the specific switching state combinations corresponding to the first switching mode, the second switching mode, and the third switching mode of the first bridge arm (or the second bridge arm) are related to the topology of the first bridge arm (or the second bridge arm) and the placement of the even number of resonant connection points.

[0111] As an example, such as Figures 23-24 As shown, the second switch Q2 is located between the first switch Q1 and the third switch Q3, and the fifth switch Q5 is located between the fourth switch Q4 and the sixth switch Q6. The even-numbered connection ports on the first side of the resonant network include a first connection port and a second connection port. The even-numbered resonant connection points include a first resonant connection point S1 located on the first bridge arm and a second resonant connection point S2 located on the second bridge arm. The first resonant connection point S1 is the connection point between the first switch Q1 and the second switch Q2, and the second resonant connection point S2 is the connection point between the fourth switch Q4 and the fifth switch Q5. The first resonant connection point S1 and the second resonant connection point S2 are respectively connected to the first connection port and the second connection port (e.g., ...). Figures 23-24 (Connect the two ends of the primary winding in the circuit).

[0112] When the first bridge arm operates in the first switching mode, the first switch Q1 is off, and both the second and third switches Q2 and Q3 are on. At this time, the voltage between the first resonant connection point S1 and the second resonant connection point S2 is the first voltage value. When the first bridge arm operates in the second switching mode, the second switch Q2 is off, and both the first and third switches Q1 and Q3 are on. At this time, the voltage between the first and second resonant connection points S1 and S2 is the second voltage value. When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first and second switches Q1 and Q2 are on. At this time, the voltage between the first and second resonant connection points S1 and S2 is the second voltage value. The first voltage value is a non-zero constant value, and the second voltage value is zero. The operating mode of the second bridge arm is similar to that of the first bridge arm and will not be described further here.

[0113] As yet another example, such as Figures 25-26 As shown, the resonant network 310 also includes a transformer T3. T3 includes a primary winding and a secondary winding. The primary winding includes a first primary winding and a second primary winding. The secondary winding includes a first secondary winding and a second secondary winding. The second switch Q2 is located between the first switch Q1 and the third switch Q3. The fifth switch Q5 is located between the fourth switch Q4 and the sixth switch Q6.

[0114] The even-numbered resonant connection points include a first resonant connection point S1 located on the first bridge arm, a second resonant connection point S2 located on the second bridge arm, a third resonant connection point S3 located on the first bridge arm, and a fourth resonant connection point S4 located on the second bridge arm. The first resonant connection point S1 is the connection point for the first switch Q1 and the second switch Q2; the second resonant connection point S2 is the connection point for the fourth switch Q4 and the fifth switch Q5; the third resonant connection point S3 is the connection point for the third switch Q3 and the second switch Q2; and the fourth resonant connection point S4 is the connection point for the sixth switch Q6 and the fifth switch Q5.

[0115] In some embodiments, such as Figures 25-26 As shown, the even-numbered connection ports on the first side of the resonant network 310 include the two ends of the first primary winding and the two ends of the second primary winding. Based on this, the first resonant connection point S1 and the second resonant connection point S2 are respectively connected to the two ends of the first primary winding, and the third resonant connection point S3 and the fourth resonant connection point S4 are respectively connected to the two ends of the second primary winding.

[0116] In other embodiments, the even number of connection ports on the first side of the resonant network 310 includes the two ends of the first secondary winding and the two ends of the second secondary winding. Based on this, the first resonant connection point S1 and the second resonant connection point S2 are respectively connected to the two ends of the first secondary winding, and the third resonant connection point S3 and the fourth resonant connection point S4 are respectively connected to the two ends of the second secondary winding.

[0117] When the first bridge arm is operating in the first switching mode, the first switch Q1 is off, and the second switch Q2 and the third switch Q3 are both on. At this time, the sum of the voltage between the first resonant connection point S1 and the second resonant connection point S2 and the voltage between the third resonant point and the fourth resonant point is the first voltage value.

[0118] When the first bridge arm is operating in the second switching mode, the second switch Q2 is off, and the first switch Q1 and the third switch Q3 are both on. At this time, the sum of the voltage between the first resonant connection point S1 and the second resonant connection point S2 and the voltage between the third resonant point and the fourth resonant point is the second voltage value.

[0119] When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first switch Q1 and the second switch Q2 are on. At this time, the sum of the voltage between the first resonant connection point S1 and the second resonant connection point S2, and the voltage between the third resonant point and the fourth resonant point, is the second voltage value. The first voltage value is zero, and the second voltage value is a non-zero constant value. The operating mode of the second bridge arm is similar to that of the first bridge arm, and will not be described further here.

[0120] As yet another example, such as Figures 27-28As shown, the third switch Q3 is located between the first switch Q1 and the second switch Q2, and the sixth switch Q6 is located between the fourth switch Q4 and the fifth switch Q5. The DC bus capacitors include a DC bus capacitor Cc1 and a second DC bus capacitor Cc2 located across the voltage source. The first DC bus capacitor Cc1 is connected across the first switch Q1 and the fourth switch Q4, and the second DC bus capacitor Cc2 is connected across the second switch Q2 and the fifth switch Q5. At least one input inductor includes a first input inductor Lg1 of the first bridge arm, a second input inductor Lg2 of the first bridge arm, a first input inductor Lj1 of the second bridge arm, and a second input inductor Lj2 of the second bridge arm. One end of the first input inductor Lg1 of the first bridge arm is connected between the second switch Q2 and the third switch Q3, and the other end of the first input inductor Lg1 of the first bridge arm is connected between the voltage source and the second DC bus capacitor Cc2. One end of the first input inductor Lj1 of the second bridge arm is connected between the fifth switch Q5 and the sixth switch Q6, and the other end of the first input inductor Lj1 of the second bridge arm is connected between the voltage source and the second DC bus capacitor Cc2. One end of the second input inductor Lg2 of the first bridge arm is connected between the first switch Q1 and the third switch Q3, and the other end of the second input inductor Lg2 of the first bridge arm is connected between the first DC bus capacitor Cc1 and the voltage source. One end of the second input inductor Lj2 of the second bridge arm is connected between the fourth switch Q4 and the sixth switch Q6, and the other end of the second input inductor Lj2 of the second bridge arm is connected between the first DC bus capacitor Cc1 and the voltage source.

[0121] The even-numbered resonant connection points include a first resonant connection point S1 located on the first bridge arm and a second resonant connection point S2 located on the second bridge arm. The even-numbered connection ports include a first connection port and a second connection port. The first resonant connection point S1 and the second resonant connection point S2 are respectively connected to the first connection port and the second connection port (e.g., Figures 27-28 (Connect the two ends of the primary winding in the circuit).

[0122] In some embodiments, such as Figure 27 As shown, the first resonant connection point S1 is the connection point between the first switch Q1 and the third switch Q3, and the second resonant connection point S2 is the connection point between the fourth switch Q4 and the sixth switch Q6.

[0123] In some embodiments, such as Figure 28 As shown, the first resonant connection point S1 is the connection point between the second switch Q2 and the third switch Q3, and the second resonant connection point S2 is the connection point between the fifth switch Q5 and the sixth switch Q6.

[0124] When the first bridge arm operates in the first switching mode, the first switch Q1 is off, and both the second and third switches Q2 and Q3 are on. At this time, the voltage between the first resonant connection point S1 and the second resonant connection point S2 is the first voltage value. When the first bridge arm operates in the second switching mode, the second switch Q2 is off, and both the first and third switches Q1 and Q3 are on. At this time, the voltage between the first and second resonant connection points S1 and S2 is the second voltage value. When the first bridge arm operates in the third switching mode, the third switch Q3 is off, and both the first and second switches Q1 and Q2 are on. At this time, the voltage between the first and second resonant connection points S1 and S2 is the second voltage value. The first voltage value is a non-zero constant value, and the second voltage value is zero. The operating mode of the second bridge arm is similar to that of the first bridge arm and will not be described further here.

[0125] It should be noted that the aforementioned switching circuit 320 can be applied to either the secondary winding or the primary winding. The above mainly focuses on... Figures 4-28 The description covers a resonant network including a transformer and a switching circuit applied to the primary winding. However, this does not limit the application of the switching circuit to the secondary winding, or even to both the primary and secondary windings. For ease of understanding, the following is simplified... Figure 29 The topology of the above switching circuit is shown when it is applied to the secondary winding.

[0126] In addition, as mentioned above Figures 3-28 The embodiments described can be understood as topologies obtained by modifying a unified circuit topology in the field of circuits. Taking the application of this unified circuit topology to the primary side of a transformer with only one bridge arm as an example, such as... Figure 30 As shown, this topology may include a voltage source ( Figure 30 The bridge consists of a capacitor bridge arm, a switching transistor bridge arm (and the first bridge arm), and an input inductor (or connecting inductor). The capacitor bridge arm includes capacitors Cc1-Cc3 connected in series, and the switching transistor bridge arm includes switching transistors Q1-Q3 connected in series. The capacitor bridge arm and the switching transistor bridge arm are connected by the input inductor (i.e., the connecting inductor). Figure 30The capacitor bridge arm (Lg1 and Lg2) is connected, and the top and bottom ends of the capacitor bridge arm are directly connected to the switching transistor bridge arm with wires. A voltage source can be connected across any capacitor in the capacitor bridge arm, with or without a filter. Without a filter, the voltage source is directly connected across any of the capacitors, and this capacitor can be omitted, effectively connecting the voltage source in series with the two remaining capacitors in the capacitor bridge arm (excluding the capacitor mentioned above). When the two remaining capacitors are adjacent, they can be replaced by a single capacitor, and in this case, they can be connected to the switching transistor bridge arm without the input inductor. Furthermore, the input inductor not connected to the voltage source can be infinite, which is equivalent to being disconnected or nonexistent. The two capacitors corresponding to this infinite inductor (i.e., the two capacitors connected in series) can be replaced by a single capacitor, or they can remain two capacitors.

[0127] As mentioned above, the resonant network also has a second side, which still has an even number of connection ports. These even number of connection ports on the second side are used to couple the second side of the resonant network to another switching circuit 330. This application does not specifically limit the structure of the other switching circuit 330. As an example, such as... Figure 4 As shown, another switching circuit 330 can be an H-bridge circuit. As another example, the other switching circuit 330 can be the same as the switching circuit 320 described above, or the other switching circuit 330 can be a half-bridge circuit.

[0128] In some embodiments, for a resonant power converter that includes both a switching circuit 320 and another switching circuit 330, the control method further includes: controlling the voltage provided by the even-numbered resonant connection points in the switching circuit 320 to the even-numbered connection ports on the first side (i.e., the output voltage of the switching circuit 320) to be in the same frequency, amplitude, and phase as the voltage at the even-numbered connection ports on the second side (i.e., the input voltage of the other switching circuit 330). Specifically, this can be achieved by controlling the duty cycle of the switching transistor in the switching circuit 320 and the duty cycle of the switching transistor in the other switching circuit 330, respectively, so that the voltage between the even-numbered resonant connection points of the switching circuit 320 and the voltage at the even-numbered connection ports on the second side have the same amplitude, the switching frequency of the switching circuit 320 and the switching frequency of the other switching circuit 330 are equal (here, the switching frequency is the resonant frequency), and there is no phase difference. This control method can reduce the overall loss of the resonant power converter in this embodiment, thereby improving the overall reliability of the power converter.

[0129] The above text combined Figures 3 to 30 The device embodiments of this application have been described in detail below, in conjunction with... Figure 31The method embodiments of this application are described in detail below. It should be understood that the description of the method embodiments corresponds to the description of the apparatus embodiments; therefore, any parts not described in detail can be referred to the foregoing apparatus embodiments.

[0130] See details Figure 31 This application provides a control method for a resonant power converter. The control method is used to control the resonant power converter described above. The resonant power converter includes a resonant network and a switching circuit. The resonant network includes a resonant circuit and has an even number of connection ports. The switching circuit includes at least one bridge arm, a DC bus capacitor, and at least one input inductor. The DC bus capacitor is connected to a voltage source to form an input circuit. The bridge arm is connected in parallel with the input circuit. At least one bridge arm has an even number of resonant connection points, which are connected to an even number of connection ports. At least one bridge arm includes a first bridge arm. At least one input inductor includes a first input inductor of the first bridge arm. The first bridge arm includes a first switch, a second switch, and a third switch connected in series. One end of the first input inductor is connected between the second and third switches, and the other end of the first input inductor is connected between the voltage source and the DC bus capacitor. The voltage source is connected across the third switch. Other topologies not described in detail can be found in the preceding description.

[0131] See details Figure 31 The control method includes step S3110.

[0132] In step S3110, the first bridge arm is controlled to operate in the first switch mode, the second switch mode, and the third switch mode during the switch control cycle, and the sum of the time the first bridge arm operates in the second switch mode and the time the first bridge arm operates in the third switch mode is equal to the time the first bridge arm operates in the first switch mode.

[0133] Specifically, when the first bridge arm operates in the first switching mode, the voltage provided by the even number of resonant connection points is the first voltage value; when the first bridge arm operates in the second switching mode, and when the first bridge arm operates in the third switching mode, the voltage provided by the even number of resonant connection points is the second voltage value.

[0134] In some embodiments, the even number of resonant connection points includes a first resonant connection point and a second resonant connection point located on the first bridge arm, and the voltage provided by the even number of resonant connection points is the voltage between the first resonant connection point and the second resonant connection point; the first voltage value is a non-zero constant value, the second voltage value is zero, the first resonant connection point and the second resonant connection point are the two ends of the first switching transistor, wherein the second switching transistor is located between the first switching transistor and the third switching transistor, or the third switching transistor is located between the first switching transistor and the second switching transistor; or, the first voltage value is zero, the second voltage value is a non-zero constant value, the first resonant connection point and the second resonant connection point are the two ends of a series circuit formed by the second switching transistor and the third switching transistor, wherein the second switching transistor is located between the first switching transistor and the third switching transistor; the control method includes: controlling the first switching transistor to be off, and the second switching transistor and the third switching transistor to be on, so that the first bridge arm operates in a first switching mode; controlling the second switching transistor to be off, and the first switching transistor and the third switching transistor to be on, so that the first bridge arm operates in a second switching mode; controlling the third switching transistor to be off, and the first switching transistor and the second switching transistor to be on, so that the first bridge arm operates in a third switching mode.

[0135] In some embodiments, the even number of resonant connection points includes a first resonant connection point and a second resonant connection point located on the first bridge arm, and the voltage provided by the even number of resonant connection points is the voltage between the first resonant connection point and the second resonant connection point; the first voltage value is a non-zero constant value, the second voltage value is zero, and the first resonant connection point and the second resonant connection point are the two ends of the second switch, wherein the second switch is located between the first switch and the third switch; or, the first voltage value is zero, the second voltage value is a non-zero constant value, and the first resonant connection point and the second resonant connection point are the two ends of the series circuit formed by the first switch and the third switch, wherein the third switch is located between the first switch and the second switch; the control method includes: controlling the second switch to be off, and both the first switch and the third switch to be on, so that the first bridge arm operates in a first switching mode; controlling the first switch to be off, and both the second switch and the third switch to be on, so that the first bridge arm operates in a second switching mode; controlling the third switch to be off, and both the first switch and the second switch to be on, so that the first bridge arm operates in a third switching mode.

[0136] In some embodiments, at least one bridge arm further includes a second bridge arm, the second bridge arm including a fourth switch, a fifth switch and a sixth switch connected in series, a voltage source also being connected to both ends of the sixth switch, and an even number of resonant connection points including resonant connection points located on the first bridge arm and resonant connection points located on the second bridge arm; the control method includes: controlling the first bridge arm to operate in a first switching mode, a second switching mode and a third switching mode during a switching control cycle; controlling the second bridge arm to operate in the same switching mode as the first bridge arm and controlling the drive signals of each switch of the second bridge arm to have a 180° phase difference relative to the drive signals of each switch of the first bridge arm.

[0137] In some embodiments, an even number of connection ports are provided on the second side of the resonant network, and the control method further includes: controlling the even number of resonant connection points to provide voltages at the even number of connection ports on the first side that are in the same frequency, amplitude and phase as the voltages at the even number of connection ports on the second side.

[0138] This application also provides a controller that can be used to execute the methods described in the above method embodiments. This application does not limit the specific implementation of the controller. For example, the controller can be implemented in hardware when executing the above methods. Alternatively, the controller can be implemented using a combination of software and hardware. Yet another example is that the controller can be implemented in software, such as by an MCU running a computer program to execute the above methods.

[0139] This application also provides a chip, including a processor, which can be used to call and run a computer program from memory, causing a power conversion circuit or power supply system on which the chip is installed to perform the methods described in the above method embodiments. It is understood that the processor can be any type of processor mentioned above. It is also understood that the memory can be independent of the chip or integrated into the chip.

[0140] This application also provides a machine-readable storage medium for storing a program. This program causes a computer to execute the methods described in the various embodiments of this application.

[0141] This application also provides a computer program product. The computer program product includes a program. The program causes a computer to perform the methods described in various embodiments of this application.

[0142] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any other combination. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this disclosure are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a machine-readable storage medium or transmitted from one machine-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The machine-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

[0143] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments of this disclosure can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0144] In the several embodiments provided in this disclosure, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0145] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0146] In addition, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0147] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A resonant power converter, characterized in that, include: A resonant network, including a resonant circuit, wherein an even number of connection ports are provided on a first side of the resonant network; A switching circuit includes: at least one bridge arm, a DC bus capacitor, and at least one input inductor. The DC bus capacitor is connected to a voltage source to form an input circuit. The bridge arm is connected in parallel with the input circuit. The at least one bridge arm has an even number of resonant connection points, and the even number of resonant connection points are connected to the even number of connection ports. Wherein, the at least one bridge arm includes a first bridge arm, and the at least one input inductor includes a first input inductor of the first bridge arm. The first bridge arm includes a first switch, a second switch, and a third switch connected in series. One end of the first input inductor is connected between the second switch and the third switch, and the other end of the first input inductor is connected between the voltage source and the DC bus capacitor. The voltage source is connected across the third switch. The first bridge arm is configured to operate in a first switching mode, a second switching mode, and a third switching mode during a switching control cycle. The sum of the time the first bridge arm operates in the second switching mode and the time the first bridge arm operates in the third switching mode is equal to the time the first bridge arm operates in the first switching mode. When the first bridge arm operates in the first switching mode, the voltage provided by the even-numbered resonant connection points is a first voltage value. When the first bridge arm operates in the second switching mode and when the first bridge arm operates in the third switching mode, the voltage provided by the even-numbered resonant connection points is a second voltage value.

2. The resonant power converter according to claim 1, characterized in that, The even number of connection ports includes a first connection port and a second connection port. The even number of resonant connection points includes a first resonant connection point and a second resonant connection point located on the first bridge arm. The first resonant connection point and the second resonant connection point are respectively connected to the first connection port and the second connection port. The voltage provided by the even number of resonant connection points is the voltage between the first resonant connection point and the second resonant connection point.

3. The resonant power converter according to claim 2, characterized in that, The second switch is located between the first switch and the third switch. The first resonant connection point and the second resonant connection point are the two ends of the first switch. When the first bridge arm operates in the first switching mode, the first switch is off, and both the second and third switches are on. When the first bridge arm operates in the second switching mode, the second switch is off, and both the first and third switches are on. When the first bridge arm operates in the third switching mode, the third switch is off, and both the first and second switches are on. The first voltage value is a non-zero constant value, and the second voltage value is zero.

4. The resonant power converter according to claim 2, characterized in that, The second switch is located between the first switch and the third switch. The first resonant connection point and the second resonant connection point are the two ends of the second switch. When the first bridge arm operates in the first switching mode, the second switch is off, and both the first and third switches are on. When the first bridge arm operates in the second switching mode, the first switch is off, and both the second and third switches are on. When the first bridge arm operates in the third switching mode, the third switch is off, and both the first and second switches are on. The first voltage value is a non-zero constant value, and the second voltage value is zero.

5. The resonant power converter according to claim 2, characterized in that, The second switch is located between the first switch and the third switch. The first resonant connection point and the second resonant connection point are the two ends of the series circuit formed by the second switch and the third switch. When the first bridge arm operates in the first switching mode, the first switch is off, and both the second switch and the third switch are on. When the first bridge arm operates in the second switching mode, the second switch is off, and both the first switch and the third switch are on. When the first bridge arm operates in the third switching mode, the third switch is off, and both the first switch and the second switch are on. The first voltage value is zero, and the second voltage value is a non-zero constant value.

6. The resonant power converter according to claim 2, characterized in that, The second switching transistor is located between the first switching transistor and the third switching transistor. The DC bus capacitor includes a first DC bus capacitor and a second DC bus capacitor connected in series. The first DC bus capacitor is connected across the first switching transistor, and the second DC bus capacitor is connected across the second switching transistor. The other end of the first input inductor of the first bridge arm is connected between the voltage source and the second DC bus capacitor. The at least one input inductor also includes a second input inductor of the first bridge arm. One end of the second input inductor of the first bridge arm is connected between the first switching transistor and the second switching transistor, and the other end of the second input inductor of the first bridge arm is connected between the first DC bus capacitor and the second DC bus capacitor.

7. The resonant power converter according to claim 2, characterized in that, The third switch is located between the first switch and the second switch. The DC bus capacitor includes a first DC bus capacitor and a second DC bus capacitor located at both ends of the voltage source. The first DC bus capacitor is connected to both ends of the first switch, and the second DC bus capacitor is connected to both ends of the second switch. The other end of the first input inductor of the first bridge arm is connected between the voltage source and the second DC bus capacitor. The at least one input inductor also includes a second input inductor of the first bridge arm. One end of the second input inductor of the first bridge arm is connected between the first switch and the third switch, and the other end of the second input inductor of the first bridge arm is connected between the first DC bus capacitor and the voltage source.

8. The resonant power converter according to claim 7, characterized in that, The first resonant connection point and the second resonant connection point are the two ends of the first switching transistor. When the first bridge arm operates in the first switching mode, the first switching transistor is off, and both the second and third switching transistors are on. When the first bridge arm operates in the second switching mode, the second switching transistor is off, and both the first and third switching transistors are on. When the first bridge arm operates in the third switching mode, the third switching transistor is off, and both the first and second switching transistors are on. The first voltage value is a non-zero constant value, and the second voltage value is zero.

9. The resonant power converter according to claim 7, characterized in that, The first resonant connection point and the second resonant connection point are the two ends of the series circuit formed by the first switch and the third switch. When the first bridge arm operates in the first switch mode, the second switch is off, and both the first switch and the third switch are on. When the first bridge arm operates in the second switch mode, the first switch is off, and both the second switch and the third switch are on. When the first bridge arm operates in the third switch mode, the third switch is off, and both the first switch and the second switch are on. The first voltage value is zero, and the second voltage value is a non-zero constant value.

10. The resonant power converter according to claim 1, characterized in that, The at least one bridge arm further includes a second bridge arm, which includes a fourth, a fifth, and a sixth switch connected in series. The voltage source is also connected to both ends of the sixth switch. The even number of resonant connection points include resonant connection points located on the first bridge arm and resonant connection points located on the second bridge arm. The first bridge arm is configured to operate in the first switching mode, the second switching mode, and the third switching mode during the switching control cycle. The second bridge arm is configured to operate in the same switching mode as the first bridge arm, and the drive signals of each switch of the second bridge arm have a 180° phase difference relative to the drive signals of each switch of the first bridge arm.

11. The resonant power converter according to claim 10, characterized in that, The even-numbered connection ports include a first connection port and a second connection port. The second switch is located between the first switch and the third switch, and the fifth switch is located between the fourth switch and the sixth switch. The even-numbered resonant connection points include a first resonant connection point located on the first bridge arm and a second resonant connection point located on the second bridge arm. The first resonant connection point is the connection point between the first switch and the second switch, and the second resonant connection point is the connection point between the fourth switch and the fifth switch. The first resonant connection point and the second resonant connection point are respectively connected to the first connection port and the second connection port.

12. The resonant power converter according to claim 10, characterized in that, The resonant network further includes a transformer, which includes a primary winding and a secondary winding. The primary winding includes a first primary winding and a second primary winding. The secondary winding includes a first secondary winding and a second secondary winding. The second switch is located between the first switch and the third switch. The fifth switch is located between the fourth switch and the sixth switch. The even number of connection ports includes both ends of the first primary winding and both ends of the second primary winding, or the even number of connection ports includes both ends of the first secondary winding and both ends of the second secondary winding. The even-numbered resonant connection points include a first resonant connection point located on the first bridge arm, a second resonant connection point located on the second bridge arm, a third resonant connection point located on the first bridge arm, and a fourth resonant connection point located on the second bridge arm. The first resonant connection point is the connection point between the first and second switching transistors, and the second resonant connection point is the connection point between the fourth and fifth switching transistors. The first and second resonant connection points are respectively connected to the two ends of the first primary winding or the two ends of the first secondary winding. The third resonant connection point is the connection point between the third and second switching transistors, and the fourth resonant connection point is the connection point between the sixth and fifth switching transistors. The third and fourth resonant connection points are respectively connected to the two ends of the second primary winding or the two ends of the second secondary winding.

13. The resonant power converter according to any one of claims 10-12, characterized in that, The at least one input inductor further includes a first input inductor of the second bridge arm, one end of which is connected between the fifth switch and the sixth switch, and the other end of which is connected between the DC bus capacitor and the voltage source.

14. The resonant power converter according to claim 10, characterized in that, The even-numbered connection ports include a first connection port and a second connection port. The third switch is located between the first switch and the second switch, and the sixth switch is located between the fourth switch and the fifth switch. The DC bus capacitor includes a first DC bus capacitor and a second DC bus capacitor located at both ends of the voltage source. The first DC bus capacitor is connected to both ends of the first switch and the fourth switch, and the second DC bus capacitor is connected to both ends of the second switch and the fifth switch. The at least one input inductor further includes a second input inductor of the first bridge arm, a first input inductor of the second bridge arm, and the second bridge arm. The second input inductor of the second bridge arm has one end connected between the fifth and sixth switches, the other end of the first input inductor of the second bridge arm and the other end of the first input inductor of the first bridge arm connected between the voltage source and the second DC bus capacitor, one end of the second input inductor of the first bridge arm connected between the first and third switches, one end of the second input inductor of the second bridge arm connected between the fourth and sixth switches, and the other ends of the second input inductors of the first and second bridge arms are both connected between the first DC bus capacitor and the voltage source; The even-numbered resonant connection points include a first resonant connection point located on the first bridge arm and a second resonant connection point located on the second bridge arm. The first resonant connection point is the connection point between the first switch and the third switch, and the second resonant connection point is the connection point between the fourth switch and the sixth switch. Alternatively, the first resonant connection point is the connection point between the second switch and the third switch, and the second resonant connection point is the connection point between the fifth switch and the sixth switch. The first resonant connection point and the second resonant connection point are respectively connected to the first connection port and the second connection port.

15. A control method for a resonant power converter, characterized in that, The resonant power converter includes a resonant network and a switching circuit. The resonant network includes a resonant circuit, and an even number of connection ports are provided on the first side of the resonant network. The switching circuit includes at least one bridge arm, a DC bus capacitor, and at least one input inductor. The DC bus capacitor is connected to a voltage source to form an input circuit. The bridge arm is connected in parallel with the input circuit. An even number of resonant connection points are provided on the at least one bridge arm, and the even number of resonant connection points are connected to the even number of connection ports. The at least one bridge arm includes a first bridge arm. The at least one input inductor includes a first input inductor of the first bridge arm. The first bridge arm includes a first switch, a second switch, and a third switch connected in series. One end of the first input inductor is connected between the second switch and the third switch, and the other end of the first input inductor is connected between the voltage source and the DC bus capacitor. The voltage source is connected to both ends of the third switch. The control method includes: The first bridge arm is controlled to operate in a first switch mode, a second switch mode, and a third switch mode during the switch control cycle, and the sum of the time the first bridge arm operates in the second switch mode and the time the first bridge arm operates in the third switch mode is equal to the time the first bridge arm operates in the first switch mode. Specifically, when the first bridge arm operates in the first switching mode, the voltage provided by the even-numbered resonant connection points is a first voltage value; when the first bridge arm operates in the second switching mode, and when the first bridge arm operates in the third switching mode, the voltage provided by the even-numbered resonant connection points is a second voltage value.

16. The control method according to claim 15, characterized in that, The even number of resonant connection points includes a first resonant connection point and a second resonant connection point located on the first bridge arm, and the voltage provided by the even number of resonant connection points is the voltage between the first resonant connection point and the second resonant connection point; The first voltage value is a non-zero constant value, the second voltage value is zero, the first resonant connection point and the second resonant connection point are the two ends of the first switching transistor, wherein the second switching transistor is located between the first switching transistor and the third switching transistor, or the third switching transistor is located between the first switching transistor and the second switching transistor; or... The first voltage value is zero, the second voltage value is a non-zero constant value, the first resonant connection point and the second resonant connection point are the two ends of the series circuit formed by the second switch and the third switch, wherein the second switch is located between the first switch and the third switch; The control method includes: The first switch is turned off, and the second and third switches are both turned on, so that the first bridge arm operates in the first switching mode. The second switch is turned off, and both the first and third switches are turned on, so that the first bridge arm operates in the second switching mode; The third switch is turned off, and both the first and second switches are turned on, so that the first bridge arm operates in the third switching mode.

17. The control method according to claim 15, characterized in that, The even number of resonant connection points includes a first resonant connection point and a second resonant connection point located on the first bridge arm, and the voltage provided by the even number of resonant connection points is the voltage between the first resonant connection point and the second resonant connection point; The first voltage value is a non-zero constant value, the second voltage value is zero, the first resonant connection point and the second resonant connection point are the two ends of the second switching transistor, wherein the second switching transistor is located between the first switching transistor and the third switching transistor; or... The first voltage value is zero, the second voltage value is a non-zero constant value, the first resonant connection point and the second resonant connection point are the two ends of the series circuit formed by the first switch and the third switch, wherein the third switch is located between the first switch and the second switch; The control method includes: The second switch is turned off, and both the first and third switches are turned on, so that the first bridge arm operates in the first switching mode. The first switch is turned off, and the second and third switches are both turned on, so that the first bridge arm operates in the second switching mode; The third switch is turned off, and both the first and second switches are turned on, so that the first bridge arm operates in the third switching mode.

18. The control method according to claim 15, characterized in that, The at least one bridge arm further includes a second bridge arm, the second bridge arm including a fourth switch, a fifth switch and a sixth switch connected in series, the voltage source is also connected to both ends of the sixth switch, and the even number of resonant connection points include resonant connection points located on the first bridge arm and resonant connection points located on the second bridge arm; The control method includes: The first bridge arm is controlled to operate in the first switching mode, the second switching mode, and the third switching mode during the switching control cycle; The second bridge arm is controlled to operate in the same switching mode as the first bridge arm, and the drive signals of each switch of the second bridge arm are controlled to have a 180° phase difference with respect to the drive signals of each switch of the first bridge arm.

19. The control method according to claim 15, characterized in that, The resonant network has an even number of connection ports on its second side, and the control method further includes: The voltage supplied to the even-numbered resonant connection points on the first side is controlled to be in the same frequency, amplitude, and phase as the voltage at the even-numbered connection ports on the second side.

20. A controller, characterized in that, Used to perform the method as described in any one of claims 15-19.

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