Resonant converter and electric vehicle charger comprising same

Abstract

According to one embodiment, the provided resonant converter for an electric vehicle charger comprises: a first input side circuit including a first switching bridge, a first resonance tank and a first primary winding; a second input side circuit which is connected in parallel to the first input side circuit and which includes a second switching bridge, a second resonance tank and a second primary winding; a first output side circuit, which includes a first secondary winding for forming a first transformer together with the first primary winding, and a first rectified network; a second output side circuit which is connected in parallel to the first output side circuit, and which includes a second secondary winding for forming a second transformer together with the second primary winding, and a second rectified network; a switch for connecting the first secondary winding and the second secondary winding; and an output capacitor shared by the first output side circuit and the second output side circuit.

Description

Resonant converter and electric vehicle charger including the same

[0001] The present disclosure relates to a resonant converter and an electric vehicle charger including the same.

[0002] Electric vehicles (EVs) are vehicles powered by electric energy. Compared to conventional internal combustion engines, they emit significantly less carbon, making them a crucial application for addressing issues like environmental pollution and climate change. However, many challenges remain before EVs can become widespread, the most pressing of which is securing charging infrastructure.

[0003] Conventional electric vehicles are equipped with 400V batteries and operate with a voltage fluctuation range of approximately 150V to 500V. However, recently, the use of 800V batteries is increasing to meet the requirements of large-capacity charging and to reduce the weight of internal vehicle structures (e.g., bus bars). 800V batteries operate with a voltage fluctuation range of approximately 300V to 1,000V. Accordingly, a power conversion circuit for electric vehicle charging that can provide charging power with high efficiency over a wide voltage range of approximately 150V to 1,000V may be required.

[0004] Various embodiments seek to provide a resonant converter with a wide range of output voltages and an electric vehicle charger including the same. The technical challenges to be addressed by the present disclosure are not limited to the technical challenges described above, and other technical challenges can be inferred from the following embodiments.

[0005] As a means for solving the above-described technical problem, a resonant converter for an electric vehicle charger according to one aspect may include: a first input circuit including a first switching bridge, a first resonant tank, and a first primary winding; a second input circuit connected in parallel with the first input circuit and including a second switching bridge, a second resonant tank, and a second primary winding; a first output circuit including a first secondary winding forming a first transformer together with the first primary winding, and a first rectifier network; a second output circuit connected in parallel with the first output circuit and including a second secondary winding forming a second transformer together with the second primary winding, and a second rectifier network; a first switch configured to electrically connect the first secondary winding and the second secondary winding in series; and a first output capacitor shared by the first output circuit and the second output circuit.

[0006] A resonant converter for an electric vehicle charger according to another aspect comprises: a first input-side circuit including a first switching bridge and a first resonant tank; a second input-side circuit connected in parallel with the first input-side circuit and including a second switching bridge and a second resonant tank; a first output-side circuit including a first rectifier network; a second output-side circuit connected in parallel with the first output-side circuit and including a second rectifier network; And a transformer network electrically and / or magnetically coupling the first input side circuit, the second input side circuit, the first output side circuit, and the second output side circuit, wherein the transformer network includes a first transformer having a primary side connected to the first input side circuit and the second input side circuit, respectively, and a secondary side connected to the first output side circuit, and a second transformer having a primary side connected to the first input side circuit and the second input side circuit, respectively, and a secondary side connected to the second output side circuit, wherein the resonant converter may further include a switch configured to electrically connect in series the secondary side of the first transformer and the secondary side of the second transformer.

[0007] According to another aspect, an electric vehicle charger comprises: an AC-DC converter for converting AC power received from an external power source into DC power; an electric reservoir for storing DC power received from the AC-DC converter; a DC-DC converter for converting DC power received from the AC-DC converter or the electric reservoir into DC power having a different voltage; and a control unit for controlling the AC-DC converter, the electric reservoir and the DC-DC converter, wherein the DC-DC converter comprises: a first input-side circuit including a first switching bridge, a first resonant tank and a first primary winding; a second input-side circuit connected in parallel with the first input-side circuit and including a second switching bridge, a second resonant tank and a second primary winding; a first secondary winding forming a first transformer together with the first primary winding, and a first output-side circuit including a first rectifier network; A second output-side circuit including a second secondary winding connected in parallel with the first output-side circuit and forming a second transformer together with the second primary winding, and a second rectifier network; a switch connecting the first secondary winding and the second secondary winding; and an output capacitor shared by the first output-side circuit and the second output-side circuit.

[0008] A resonant converter and an electric vehicle charger including the same according to various embodiments of the present disclosure can provide a wide range of output voltages.

[0009] Furthermore, the resonant converter and the electric vehicle charger including the same according to various embodiments of the present disclosure can perform conversion between series and parallel connections of power conversion circuits with a single switch by arranging a switch between the secondary windings of the output circuits. Accordingly, the circuit configuration for conversion between series and parallel connections within the power conversion system can be reduced in space. Furthermore, reliability can be increased compared to when multiple switches are used.

[0010] In addition, the resonant converter and the electric vehicle charger including the same according to various embodiments of the present disclosure may employ a structure and control method for reducing the voltage / current stress of an equivalent transformer for transmitting the same output power, reducing the switching stress of bridge switches, or performing current balancing between power conversion circuits.

[0011] The effects of the embodiments are not limited to the effects described above, and effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the embodiments belong from this specification and the attached drawings.

[0012] FIG. 1 is a circuit diagram illustrating a resonant converter according to one embodiment.

[0013] FIG. 2 is a circuit diagram for explaining a resonant converter when a switch is open according to one embodiment.

[0014] Figures 3a to 3c are simulation result drawings of the resonant converter according to Figure 2.

[0015] FIG. 4 is a circuit diagram for explaining a resonant converter when a switch is closed according to one embodiment.

[0016] Figures 5a to 5c are simulation result drawings of the resonant converter according to Figure 4.

[0017] Fig. 6 is a circuit diagram illustrating a resonant converter according to another embodiment.

[0018] FIGS. 7 to 9b are circuit diagrams illustrating resonant converters according to further embodiments.

[0019] FIG. 10 is a block diagram of an electric vehicle charger according to one embodiment.

[0020] A resonant converter for an electric vehicle charger according to one embodiment may include: a first input circuit including a first switching bridge, a first resonant tank, and a first primary winding; a second input circuit connected in parallel with the first input circuit and including a second switching bridge, a second resonant tank, and a second primary winding; a first output circuit including a first secondary winding forming a first transformer together with the first primary winding, and a first rectifier network; a second output circuit connected in parallel with the first output circuit and including a second secondary winding forming a second transformer together with the second primary winding, and a second rectifier network; a first switch configured to electrically connect the first secondary winding and the second secondary winding in series; and a first output capacitor shared by the first output circuit and the second output circuit.

[0021] The first input-side circuit and the first output-side circuit constitute a first power conversion circuit, the second input-side circuit and the second output-side circuit constitute a second power conversion circuit, and when the first switch is opened, the first transformer and the second transformer are connected in parallel, and a DC output voltage can be applied to the first output capacitor by independent operations of the first power conversion circuit and the second power conversion circuit.

[0022] In one embodiment, the first power conversion circuit and the second power conversion circuit may operate in an interleaved manner to reduce current ripple.

[0023] When the first switch is closed, the first transformer and the second transformer are connected in series, and the sum of the output voltage of the first output-side circuit and the output voltage of the second output-side circuit can be applied to the first output capacitor.

[0024] Each of the first switching bridge and the second switching bridge includes a plurality of bridge switches controlled by at least one switching signal and can generate a square wave output from a direct current input voltage.

[0025] The first resonant tank and the second resonant tank are coupled to the first switching bridge and the second switching bridge, respectively, and each of the first resonant tank and the second resonant tank may include a resonant inductor and a resonant capacitor connected in series.

[0026] Each of the first transformer and the second transformer can change the strength of the AC voltage in proportion to the turns ratio between the primary winding and the secondary winding.

[0027] Each of the first rectifier network and the second rectifier network may include a plurality of bridge diodes for converting an AC input into a DC output.

[0028] In one embodiment, the first switch may be a single switching element.

[0029] For example, the first switch may include at least one of a metal-oxide-semiconductor field-effect transistor (MOSFET), a bipolar junction transistor (BJT), a gate turn-off thyristor (GTO), an integrated gate commutated thyristor (IGCT), an isolated gate bipolar transistor (IGBT), and a relay.

[0030] The resonant converter may further include: a third input circuit including a third switching bridge, a third resonant tank, and a third primary winding; a fourth input circuit connected in parallel with the third input circuit and including a fourth switching bridge, a fourth resonant tank, and a fourth primary winding; a third output circuit including a third secondary winding forming a third transformer together with the third primary winding, and a third rectifier network; a fourth output circuit connected in parallel with the third output circuit and including a fourth secondary winding forming a fourth transformer together with the fourth primary winding, and a fourth rectifier network; a second switch configured to electrically connect the third secondary winding and the fourth secondary winding in series; and a second output capacitor shared by the third output circuit and the fourth output circuit.

[0031] The third input-side circuit and the third output-side circuit constitute a third power conversion circuit, the fourth input-side circuit and the fourth output-side circuit constitute a fourth power conversion circuit, and when the second switch is opened, the third transformer and the fourth transformer are connected in parallel, and a DC output voltage can be applied to the second output capacitor by independent operation of the third power conversion circuit and the fourth power conversion circuit.

[0032] In addition, when the second switch is closed, the third transformer and the fourth transformer are connected in series, and the sum of the output voltage of the third output-side circuit and the output voltage of the fourth output-side circuit can be applied to the second output capacitor.

[0033] In one embodiment, the first input-side circuit and the second input-side circuit may be connected in parallel with the third input-side circuit and the fourth input-side circuit, and the first output-side circuit and the second output-side circuit may be connected in parallel with the third output-side circuit and the fourth output-side circuit.

[0034] In another embodiment, the first input side circuit and the second input side circuit may be connected in series with the third input side circuit and the fourth input side circuit, and the first output side circuit and the second output side circuit may be connected in parallel with the third output side circuit and the fourth output side circuit.

[0035] A resonant converter for an electric vehicle charger according to another embodiment comprises: a first input-side circuit including a first switching bridge and a first resonant tank; a second input-side circuit connected in parallel with the first input-side circuit and including a second switching bridge and a second resonant tank; a first output-side circuit including a first rectifier network; a second output-side circuit connected in parallel with the first output-side circuit and including a second rectifier network; And a transformer network electrically and / or magnetically coupling the first input side circuit, the second input side circuit, the first output side circuit, and the second output side circuit, wherein the transformer network includes a first transformer having a primary side connected to the first input side circuit and the second input side circuit, respectively, and a secondary side connected to the first output side circuit, and a second transformer having a primary side connected to the first input side circuit and the second input side circuit, respectively, and a secondary side connected to the second output side circuit, wherein the resonant converter may further include a switch configured to electrically connect in series the secondary side of the first transformer and the secondary side of the second transformer.

[0036] According to another embodiment, an electric vehicle charger comprises: an AC-DC converter for converting AC power received from an external power source into DC power; an electric reservoir for storing DC power received from the AC-DC converter; a DC-DC converter for converting DC power received from the AC-DC converter or the electric reservoir into DC power having a different voltage; and a control unit for controlling the AC-DC converter, the electric reservoir and the DC-DC converter, wherein the DC-DC converter comprises: a first input-side circuit including a first switching bridge, a first resonant tank and a first primary winding; a second input-side circuit connected in parallel with the first input-side circuit and including a second switching bridge, a second resonant tank and a second primary winding; a first secondary winding forming a first transformer together with the first primary winding, and a first output-side circuit including a first rectifier network; A second output-side circuit including a second secondary winding connected in parallel with the first output-side circuit and forming a second transformer together with the second primary winding, and a second rectifier network; a switch connecting the first secondary winding and the second secondary winding; and an output capacitor shared by the first output-side circuit and the second output-side circuit.

[0037] The first input-side circuit and the first output-side circuit constitute a first power conversion circuit, the second input-side circuit and the second output-side circuit constitute a second power conversion circuit, and when the switch is opened, the first transformer and the second transformer are connected in parallel, and the DC-DC converter can output a direct current output voltage by independent operation of the first power conversion circuit and the second power conversion circuit.

[0038] In one embodiment, the first power conversion circuit and the second power conversion circuit may operate in an interleaved manner to reduce current ripple.

[0039] When the switch is closed, the first transformer and the second transformer are connected in series, and the sum of the output voltage of the first output-side circuit and the output voltage of the second output-side circuit can be applied to the output capacitor.

[0040] The terms used in the examples have been selected from widely used, current terms, taking into account the functions of the present invention. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in the present invention should be defined not simply based on their names, but based on their inherent meanings and the overall content of the present invention.

[0041] When a part of the specification is said to "include" a component, this does not exclude other components, but rather implies the inclusion of other components, unless otherwise specifically stated. Furthermore, terms such as "-unit" and "-module" used in the specification refer to a unit that processes at least one function or operation, which may be implemented in hardware, software, or a combination of hardware and software.

[0042] As used herein, when an expression such as "at least one" precedes an array of elements, it modifies the entire array of elements, not just each individual element. For example, the expression "at least one of a, b, and c" should be interpreted to include a, b, c, or a and b, a and c, b and c, or a and b and c.

[0043] Below, with reference to the attached drawings, embodiments of the present disclosure are described in detail so that those skilled in the art can easily implement them. The present disclosure may be implemented in a form that can be implemented in the various embodiments of the aerosol generating devices described above, or may be implemented in various different forms and is not limited to the embodiments described herein.

[0044] FIG. 1 is a circuit diagram illustrating a resonant converter according to one embodiment.

[0045] Referring to FIG. 1, a resonant converter (10) for an electric vehicle charger is illustrated. The resonant converter (10) may refer to a device that converts power using a resonant circuit. The resonant converter (10) may be a DC-DC converter that converts input DC power into DC power having a different voltage and outputs it. The resonant converter (10) may be employed in an electric vehicle charger, and more specifically, may be arranged inside a power module for an electric vehicle charger. In addition to the resonant converter (10), the power module may further include a controller for controlling the resonant converter (10), a cooler for cooling the resonant converter (10), a socket portion including terminals for electrically connecting an external device to the resonant converter (10), and at least one of other types of converters.

[0046] The resonant converter (10) comprises a first switching bridge, a first resonant tank, and a first primary winding (N PA ) may include a first input side circuit including a first switching bridge. In one embodiment, the first switching bridge comprises a plurality of bridge switches (Q) controlled by at least one switching signal. 1A , Q 2A , Q 3A and Q 4A ) may be included. The first switching bridge may include a DC input voltage (V IN) can generate a square wave output. The square wave output is generated by the first resonant tank and the first primary winding (N PA ) can be transmitted.

[0047] The first resonant tank is coupled to the first switching bridge and has a resonant inductor (L) connected in series. RA ) and resonant capacitor (C RA ) may be included. However, it is not necessarily limited thereto, and the first resonant tank may include a combination of at least one resonant inductor and at least one resonant capacitor connected in series or parallel.

[0048] The resonant converter (10) is connected in parallel with the first input side circuit, and includes a second switching bridge, a second resonant tank, and a second primary winding (N PB ) may include a second input side circuit including a second switching bridge. In one embodiment, the second switching bridge comprises a plurality of bridge switches (Q) controlled by at least one switching signal. 1B , Q 2B , Q 3B and Q 4B ) may be included. The second switching bridge may include a DC input voltage (V IN ) can generate a square wave output. The square wave output is generated by the second resonant tank and the second primary winding (N PB ) can be transmitted.

[0049] The second resonant tank is coupled to the second switching bridge and has a resonant inductor (L) connected in series. RB ) and resonant capacitor (C RB ) may be included. However, it is not necessarily limited thereto, and the second resonant tank may include a combination of at least one resonant inductor and at least one resonant capacitor connected in series or parallel.

[0050] Meanwhile, although Fig. 1 illustrates the first switching bridge and the second switching bridge as a full bridge configuration each including four bridge switches, this is not necessarily limited thereto. At least one of the first switching bridge and the second switching bridge may be a half bridge configuration including two bridge switches. In addition, at least one of the first switching bridge and the second switching bridge may be a full bridge configuration, but may operate in the same manner as a half bridge through control using a switching signal.

[0051] The resonant converter (10) has a first primary winding (N PA ) with the first transformer (T A ) constitutes the first secondary winding (N SA ), and a first output side circuit including a first rectifier network. A first transformer (T A ) is the first primary winding (N PA ) and first secondary winding (N SA ) can change the strength of the AC voltage in proportion to the turns ratio between the first input circuit and the first output circuit. The first resonant tank can form a first power conversion circuit. The first resonant tank can be a resonant inductor (L RA ) and resonant capacitor (C RA ) and includes a first transformer (T A ) has a magnetizing inductance, the first power conversion circuit may correspond to an LLC converter. The first rectifier network includes a plurality of bridge diodes (D) for converting AC input to DC output. R1A , D R2A , D R3A and D R4A ) may be included.

[0052] The resonant converter (10) is connected in parallel with the first output side circuit and the second primary winding (N PB ) with the second transformer (T B ) forming the second secondary winding (N SB), and a second output side circuit including a second rectifier network. A second transformer (T B ) is the second primary winding (N PB ) and the second secondary winding (N SB ) can change the strength of the AC voltage in proportion to the turns ratio between the input and output circuits. The second input circuit and the second output circuit can form a second power conversion circuit. The second resonant tank may include a resonant inductor (L RB ) and resonant capacitor (C RB ) and a second transformer (T B ) has a magnetizing inductance, the second power conversion circuit may correspond to an LLC converter. The second rectifier network includes a plurality of bridge diodes (D) for converting AC input to DC output. R1B , D R2B , D R3B and D R4B ) may be included.

[0053] The resonant converter (10) has a first secondary winding (N SA ) and the second secondary winding (N SB ) is configured to electrically connect in series a switch (Q) A ) may be included. For example, a switch (Q A ) is the first secondary winding (N SA ) and the second secondary winding (N SB ) is placed between the first secondary winding (N SA ) and the second secondary winding (N SB ) can be optionally connected. Switch (Q A) may include at least one of a metal-oxide-semiconductor field-effect transistor (MOSFET), a bipolar junction transistor (BJT), a gate turn-off thyristor (GTO), an integrated gate commutated thyristor (IGCT), an isolated gate bipolar transistor (IGBT), and a relay. However, the present invention is not limited thereto, and a switch (Q A ) may be another type of switch, including a two-way switch.

[0054] The resonant converter (10) has an output capacitor (C) shared by the first output side circuit and the second output side circuit. O ) may include a switch (Q A ) depending on whether the first transformer (T) is opened or closed A ) and the second transformer (T B ) can be connected in series or parallel. The first transformer (T A ) and the second transformer (T B ) are connected in series, the output capacitor (C O ) and the range of output voltage applied to the first transformer (T A ) and the second transformer (T B ) are connected in parallel, the output capacitor (C O ) may have different ranges of output voltages applied to each other.

[0055] Transformer 1 (T A ) and the second transformer (T B ) are connected in series, the output capacitor (C O) is applied with the sum of the output voltage of the first output-side circuit and the output voltage of the second output-side circuit. Therefore, an output voltage having a voltage fluctuation range twice that of a single power conversion circuit (e.g., a single LLC converter) can be provided. When a relatively low output voltage is required, the switch (Q A ) is open, and when a relatively high output voltage is required, the switch (Q A ) can be closed. In this way, the resonant converter (10) according to the present disclosure can provide a wide range of output voltages. The resonant converter (10) includes a switch (Q A ) may further include a control circuit for determining whether to open or close.

[0056] Meanwhile, the switch (Q A ) may be a single switching element. In this way, the resonant converter (10) according to the present disclosure may be a single switch (Q A ) alone can perform conversion between series and parallel connections of power conversion circuits. Accordingly, the circuit configuration space required for conversion between series and parallel connections within a power conversion system can be reduced. In addition, reliability can be increased compared to when multiple switches are used.

[0057] The operation of the resonant converter (10) when the switch is open or closed will be described in detail with reference to FIGS. 2 to 5c below.

[0058] FIG. 2 is a circuit diagram for explaining a resonant converter when a switch is open according to one embodiment.

[0059] Referring to Figure 2, the switch (Q A ) is shown as a resonant converter (10) when the switch (Q) is opened. A ) is opened, the first transformer (T A ) and the second transformer (T B) are connected in parallel (via the first and second rectifier networks), and the resonant converter (10) can output a DC output voltage by independent operation of the first power conversion circuit and the second power conversion circuit.

[0060] Transformer 1 (T A ) and the second transformer (T B ) are connected in parallel, the resonant converter (10) is connected to the first transformer (T A ) and the second transformer (T B ) provide a lower output voltage than when connected in series, but can provide greater current instead.

[0061] In one embodiment, the first power conversion circuit and the second power conversion circuit may operate in an interleaved manner to reduce current ripple. However, this is not necessarily limited. The first power conversion circuit and the second power conversion circuit may also operate in synchronization with the same timing by the same switching signals.

[0062] Figures 3a to 3c are simulation result drawings of the resonant converter according to Figure 2.

[0063] Referring to FIGS. 3A to 3C, simulation results corresponding to cases where the output voltage of the resonant converter (10) is 500 V, 400 V, and 260 V are shown, respectively. For example, FIGS. 3A to 3C show the output voltage (V) of the resonant converter (10). O ), first primary winding (N PA ) primary side resonant current (I) flowing through PA ), switching signals (V) for controlling the first and second switching bridges gs1 and V gs2 ), and the current (I) flowing through each of the bridge diodes included in the first and second rectifier networks D_R1A , I D_R2A , I D_R3A , I D_R4A , I D_R1B, I D_R2B , I D_R3B and I D_R4B ) is shown.

[0064] Here, the switching signal (V gs1 ) are bridge switches Q included in the first switching bridge. 1A and Q 4A is applied, and a switching signal (V gs2 ) are bridge switches Q included in the first switching bridge. 2A and Q 3A can be applied. In addition, the switching signal (V gs1 ) are bridge switches Q included in the second switching bridge. 1B and Q 4B is applied, and a switching signal (V gs2 ) are bridge switches Q included in the second switching bridge. 2B and Q 3B may be authorized.

[0065] Referring to the examples of FIGS. 3a to 3c, the switch (Q A ) is opened, it can be seen that the DC output voltage of the resonant converter (10) can be provided in a range of at least about 260 V to 500 V by the independent operation of the first power conversion circuit and the second power conversion circuit. The output voltage of the resonant converter (10) is ... gs1 and V gs2 ) can be changed according to the frequency or duty cycle of the resonant converter (10), but the range of output voltage that can supply efficient power is inevitably limited. Therefore, in order to provide a wider range of output voltage of the resonant converter (10), the switching signals (V gs1 and V gs2 ) may require additional methods beyond control based on frequency or duty cycle.

[0066] FIG. 4 is a circuit diagram for explaining a resonant converter when a switch is closed according to one embodiment.

[0067] Referring to Figure 4, the switch (Q A ) is closed. A resonant converter (10) is shown. The switch (Q A ) is closed, the first transformer (T A ) and the second transformer (T B ) are connected in series, and the output capacitor (C O ) can be applied with the sum of the output voltage of the first output side circuit and the output voltage of the second output side circuit.

[0068] Figures 5a to 5c are simulation result drawings of the resonant converter according to Figure 4.

[0069] Referring to FIGS. 5A to 5C, simulation results corresponding to cases where the output voltage of the resonant converter (10) is 1,000 V, 800 V, and 600 V are shown, respectively. For example, FIGS. 5A to 5C show the output voltage (V) of the resonant converter (10). O ), first primary winding (N PA ) primary side resonant current (I) flowing through PA ), switching signals (V) for controlling the first and second switching bridges gs1 and V gs2 ), and the current (I) flowing through each of the bridge diodes included in the first and second rectifier networks D_R1A , I D_R2A , I D_R3A , I D_R4A , I D_R1B , I D_R2B , I D_R3B and I D_R4B ) is shown.

[0070] Here, the switching signal (V gs1 ) are bridge switches Q included in the first switching bridge. 1A and Q 4A is applied, and a switching signal (V gs2 ) are bridge switches Q included in the first switching bridge. 2A and Q 3Acan be applied. In addition, the switching signal (V gs1 ) are bridge switches Q included in the second switching bridge. 1B and Q 4B is applied, and a switching signal (V gs2 ) are bridge switches Q included in the second switching bridge. 2B and Q 3B may be authorized.

[0071] Switch (Q A ) is closed, the switch (Q A ) and diodes directly connected to the R3A , D R4A , D R1B , D R2B ) is not operated and is opened. Accordingly, the first secondary winding (N SA ) and the second secondary winding (N SB ) and the output voltage is divided, and the resonant converter (10) can withstand high output voltage.

[0072] Referring to the examples of FIGS. 5A to 5C, the switch (Q A ) is closed, it can be seen that the DC output voltage of the resonant converter (10) can be provided in a range of at least about 600 V to 1,000 V by the combination of the first power conversion circuit and the second power conversion circuit. In other words, the resonant converter (10) according to the present disclosure can be provided by the switch (Q) when a high output voltage is required. A ) can be seen to efficiently provide twice the output voltage by operating in a closed state.

[0073] Meanwhile, the numerical values, such as the output voltage, illustrated in FIGS. 3A to 3C and FIGS. 5A to 5C are merely examples and are not intended to limit the various embodiments according to the present disclosure. Those skilled in the art will readily understand that numerical values, such as the output voltage, may vary as the parameters of the circuit elements constituting the resonant converter (10) change.

[0074] Fig. 6 is a circuit diagram illustrating a resonant converter according to another embodiment.

[0075] Referring to FIG. 6, a resonant converter (60) according to an embodiment different from that of FIG. 1 is illustrated.

[0076] A resonant converter (60) may include an input-side circuit including a switching bridge, a resonant tank, and a primary winding. In one embodiment, the switching bridge comprises a plurality of bridge switches (Q) controlled by at least one switching signal. 1A , Q 2A , Q 3A and Q 4A ) may be included. The switching bridge may have a DC input voltage (V IN ) can generate a square wave output. The square wave output is generated by a resonant tank and a primary winding (N PA ) can be transmitted. The resonant tank is coupled to the switching bridge and the resonant inductor (L) is connected in series RA ) and resonant capacitor (C RA ) may be included. However, it is not necessarily limited thereto, and the resonant tank may include a combination of at least one resonant inductor and at least one resonant capacitor connected in series or parallel.

[0077] Meanwhile, while FIG. 6 illustrates the switching bridge as a full bridge configuration comprising four bridge switches, this is not necessarily limited. The switching bridge may also be a half bridge configuration comprising two bridge switches. Furthermore, the switching bridge may be a full bridge configuration but operate in the same manner as a half bridge through control using switching signals.

[0078] The resonant converter (60) has a primary winding (N PA ) with the first transformer (T A ) constitutes the first secondary winding (N SA), and a first output side circuit including a first rectifier network. A first transformer (T A ) is the primary winding (N PA ) and first secondary winding (N SA ) can change the strength of the AC voltage in proportion to the turns ratio between the two. The first rectifier network comprises a plurality of bridge diodes (D) for converting AC input into DC output. R1A , D R2A , D R3A and D R4A ) may be included.

[0079] In addition, the resonant converter (60) is connected in parallel with the first output side circuit and the primary winding (N PA ) with the second transformer (T B ) forming the second secondary winding (N SB ), and a second output side circuit including a second rectifier network. The second transformer (T B ) is the primary winding (N PA ) and the second secondary winding (N SB ) can change the strength of the AC voltage in proportion to the turns ratio between the two. The second rectifier network comprises a plurality of bridge diodes (D) for converting the AC input into a DC output. R1B , D R2B , D R3B and D R4B ) may be included.

[0080] The resonant converter (60) has a first secondary winding (N SA ) and the second secondary winding (N SB ) to connect the switch (Q A ) may be included. In addition, the resonant converter (60) may include an output capacitor (C) shared by the first output side circuit and the second output side circuit. O ) may be included.

[0081] The resonant converter (60) of Fig. 6 differs from the resonant converter (10) of Fig. 1 only in that a single input circuit is employed instead of two input circuits connected in parallel. Therefore, redundant descriptions may be omitted. In the resonant converter (60) of Fig. 6, a switch (Q) is also A ) depending on whether the first transformer (T) is opened or closed A ) and the second transformer (T B ) can be connected in series or parallel. In addition, the resonant converter (60) is connected by a switch (Q A ) can be opened and closed to provide a wide range of output voltages.

[0082] FIGS. 7 to 9b are circuit diagrams illustrating resonant converters according to further embodiments.

[0083] Referring to FIG. 7, a resonant converter (70) according to another embodiment may further include a third input-side circuit (710c), a fourth input-side circuit (710d), a third output-side circuit (720c), and a fourth output-side circuit (720d), compared to the resonant converter (10) of FIG. 1. The third input-side circuit (710c) and the fourth input-side circuit (710d) may have substantially the same structure as the first input-side circuit (710a) and the second input-side circuit (710b), and the third output-side circuit (720c) and the fourth output-side circuit (720d) may have substantially the same structure as the first output-side circuit (720a) and the second output-side circuit (720b).

[0084] First output capacitor (C O1 ) is shared by the first output side circuit (720a) and the second output side circuit (720b), and the second output capacitor (C O2 ) can be shared by the third output side circuit (720c) and the fourth output side circuit (720d).

[0085] The third input side circuit (710c) includes a third switching bridge, a third resonant tank, and a third primary winding (NPC ) may include. In one embodiment, the third switching bridge comprises a plurality of bridge switches (Q) controlled by at least one switching signal. 1C , Q 2C , Q 3C and Q 4C ) may be included. The third switching bridge may include a DC input voltage (V IN ) can generate a square wave output. The square wave output is generated by the third resonant tank and the third primary winding (N PC ) can be transmitted.

[0086] The third resonant tank is coupled to the third switching bridge and has a series-connected resonant inductor (L RC ) and resonant capacitor (C RC ) may be included. However, it is not necessarily limited thereto, and the third resonant tank may include a combination of at least one resonant inductor and at least one resonant capacitor connected in series or parallel.

[0087] The fourth input side circuit (710d) is connected in parallel with the third input side circuit (710c) and includes a fourth switching bridge, a fourth resonant tank, and a fourth primary winding (N PD ) may include. In one embodiment, the fourth switching bridge comprises a plurality of bridge switches (Q) controlled by at least one switching signal. 1D , Q 2D , Q 3D and Q 4D ) may be included. The fourth switching bridge may include a DC input voltage (V IN ) can generate a square wave output. The square wave output is generated by the fourth resonant tank and the fourth primary winding (N PD ) can be transmitted.

[0088] The fourth resonant tank is coupled to the fourth switching bridge and has a series-connected resonant inductor (L RD ) and resonant capacitor (C RD) may be included. However, it is not necessarily limited thereto, and the fourth resonant tank may include a combination of at least one resonant inductor and at least one resonant capacitor connected in series or parallel.

[0089] Meanwhile, although Fig. 7 illustrates the third switching bridge and the fourth switching bridge as a full bridge configuration each including four bridge switches, this is not necessarily limited thereto. At least one of the third switching bridge and the fourth switching bridge may be a half bridge configuration including two bridge switches. Furthermore, at least one of the third switching bridge and the fourth switching bridge may be a full bridge configuration, but may operate in the same manner as a half bridge through control using a switching signal.

[0090] The third output side circuit (720c) is the third primary winding (N PC ) forming the third transformer with the third secondary winding (N SC ), and a third rectifier network. The third transformer may include a third primary winding (N PC ) and third secondary winding (N SC ) can change the strength of the AC voltage in proportion to the turns ratio between the third input side circuit (710c) and the third output side circuit (720c) can form a third power conversion circuit. The third resonant tank can be a resonant inductor (L RC ) and resonant capacitor (C RC ) and the third transformer has a magnetizing inductance, so the third power conversion circuit may correspond to an LLC converter. The third rectifier network includes a plurality of bridge diodes (D) for converting an AC input into a DC output. R1C , D R2C , D R3C and D R4C ) may be included.

[0091] The fourth output side circuit (720d) is connected in parallel with the third output side circuit (720c), and the fourth primary winding (N PD ) forming the fourth transformer along with the fourth secondary winding (N PD ), and a fourth rectifier network. The fourth transformer may include a fourth primary winding (N PD ) and the fourth secondary winding (N SD ) can change the strength of the AC voltage in proportion to the turns ratio between the input circuit (710d) and the output circuit (720d). The fourth input circuit (710d) and the fourth output circuit (720d) can form the fourth power conversion circuit. The fourth resonant tank may be a resonant inductor (L RD ) and resonant capacitor (C RD ) and the fourth transformer has a magnetizing inductance, so the fourth power conversion circuit may correspond to an LLC converter. The fourth rectifier network includes a plurality of bridge diodes (D) for converting an AC input into a DC output. R1D , D R2D , D R3D and D R4D ) may be included.

[0092] The resonant converter (70) has a third secondary winding (N SC ) and the fourth secondary winding (N SD ) configured to electrically connect in series a second switch (Q) B ) may be included. The second switch (Q B ) is the first switch (Q) described with reference to FIG. 1. A ) is practically the same, so any duplicate explanations are omitted.

[0093] Second switch (Q B ) can be connected in series or parallel depending on whether the third transformer and the fourth transformer are connected in series or parallel. If the third transformer and the fourth transformer are connected in series, the second output capacitor (C O2 ) and the range of output voltage applied to the second output capacitor (C) when the third transformer and the fourth transformer are connected in parallel. O2) may have different ranges of output voltages applied to each other.

[0094] For example, the second switch (Q B ) is opened, the third and fourth transformers are connected in parallel, and the second output capacitor (C O2 ) can be applied with a DC output voltage by independent operation of the third power conversion circuit and the fourth power conversion circuit. In addition, the second switch (Q B ) is closed, the third and fourth transformers are connected in series, and the second output capacitor (C O2 ) can be applied with the sum of the output voltage of the third output side circuit (720c) and the output voltage of the fourth output side circuit (720d).

[0095] Referring to FIG. 7, the first input-side circuit (710a) and the second input-side circuit (710b) may be connected in parallel with the third input-side circuit (710c) and the fourth input-side circuit (710d), and the first output-side circuit (720a) and the second output-side circuit (720b) ​​may be connected in parallel with the third output-side circuit (720c) and the fourth output-side circuit (720d). In other words, the first input-side circuit (710a), the second input-side circuit (710b), the third input-side circuit (710c), and the fourth input-side circuit (710d) may all be connected in parallel, and the first output-side circuit (720a), the second output-side circuit (720b), the third output-side circuit (720c), and the fourth output-side circuit (720d) may all be connected in parallel.

[0096] 1st switch (Q A ) and the second switch (Q B ) are all open, the first transformer and the second transformer can be connected in parallel through the first and second rectifier networks, and the third transformer and the fourth transformer can be connected in parallel through the third and fourth rectifier networks. The first switch (Q A ) and the second switch (Q B) are all opened, the output voltage of the resonant converter (70) is the switch (Q) in the resonant converter (10) of Fig. 1. A ) can be the same as the output voltage when the resonant converter (10) of Fig. 1 is opened. However, compared to the resonant converter (10) of Fig. 1, the resonant converter (70) of Fig. 7 can significantly reduce the voltage / current stress of the equivalent transformer for transmitting the same output power.

[0097] 1st switch (Q A ) and the second switch (Q B ) are all closed, the first and second transformers are connected in series, and the third and fourth transformers can also be connected in series. Accordingly, the first output capacitor (C O1 ) is applied with the sum of the output voltage of the first output side circuit (720a) and the output voltage of the second output side circuit (720b), and the second output capacitor (C O2 ) can be applied with the sum of the output voltage of the third output side circuit (720c) and the output voltage of the fourth output side circuit (720d). The first switch (Q A ) and the second switch (Q B ) are all closed, the output voltage of the resonant converter (70) is A ) and the second switch (Q B ) can be twice the output voltage of the resonant converter (70) when all of the switches are open.

[0098] Meanwhile, the first switch (Q A ) and the second switch (Q B ) are all closed, the output voltage of the resonant converter (70) is the switch (Q) in the resonant converter (10) of Fig. 1. A ) may be the same as the output voltage when the circuit is closed. However, compared to the resonant converter (10) of Fig. 1, the resonant converter (70) of Fig. 7 can significantly reduce the voltage / current stress of the equivalent transformer for transmitting the same output power.

[0099] Referring to Fig. 8, a primary circuit of a resonant converter (80) according to another embodiment is illustrated. Since the resonant converter (80) includes the same secondary circuit as the resonant converter (70) of Fig. 7, only the primary circuit is illustrated in Fig. 8 for convenience of explanation. In other words, the resonant converter (80) may include the same first output-side circuit (720a), second output-side circuit (720b), third output-side circuit (720c), and fourth output-side circuit (720d) of Fig. 7.

[0100] Similar to FIG. 7, the first output-side circuit (720a) may be magnetically coupled to the first input-side circuit (810a) through the first transformer, the second output-side circuit (720b) ​​may be magnetically coupled to the second input-side circuit (810b) through the second transformer, the third output-side circuit (720c) may be magnetically coupled to the third input-side circuit (810c) through the third transformer, and the fourth output-side circuit (720d) may be magnetically coupled to the fourth input-side circuit (810d) through the fourth transformer. In addition, the first output-side circuit (720a) and the second output-side circuit (720b) ​​may be connected in parallel with the third output-side circuit (720c) and the fourth output-side circuit (720d).

[0101] Each of the first input side circuit (810a), the second input side circuit (810b), the third input side circuit (810c), and the fourth input side circuit (810d) may have substantially the same structure as each of the first input side circuit (710a), the second input side circuit (710b), the third input side circuit (710c), and the fourth input side circuit (710d) of FIG. 7.

[0102] The resonant converter (80) of Fig. 8 differs from the resonant converter (70) of Fig. 7 only in that the first input-side circuit (810a) and the second input-side circuit (810b) are connected in series with the third input-side circuit (810c) and the fourth input-side circuit (810d). As the first input-side circuit (810a) and the second input-side circuit (810b) are connected in series with the third input-side circuit (810c) and the fourth input-side circuit (810d), the input voltage applied to each of the first input-side circuit (810a), the second input-side circuit (810b), the third input-side circuit (810c), and the fourth input-side circuit (810d) can be reduced by half. Accordingly, the switching stress of the bridge switches included in the primary circuit of the resonant converter (80) can be reduced.

[0103] Meanwhile, while the resonant converter (10) of FIG. 1 corresponds to a combination of two power conversion circuits (e.g., LLC converters), the resonant converter (70) of FIG. 7 and the resonant converter (80) of FIG. 8 correspond to a combination of four power conversion circuits. For example, the primary circuit of the resonant converter (70) of FIG. 7 may be referred to as a four-parallel structure, and the primary circuit of the resonant converter (80) of FIG. 8 may be referred to as a two-parallel-two-series structure. In the present disclosure, only the combination of four power conversion circuits has been described to avoid redundant explanation, but a person skilled in the art will readily understand that the resonant converter according to the present disclosure may include a combination of more than four power conversion circuits, or may employ various combinations of series and / or parallel connections of the primary or secondary circuits.

[0104] Referring to FIGS. 9a and 9b, a resonant converter (90) according to another embodiment is illustrated.

[0105] A resonant converter (90) may include a first input-side circuit including a first switching bridge and a first resonant tank. In one embodiment, the first switching bridge includes a plurality of bridge switches (Q) controlled by at least one switching signal. 1A , Q 2A , Q 3A and Q 4A ) may be included. The first switching bridge may include a DC input voltage (V IN ) can generate a square wave output.

[0106] The first resonant tank is coupled to the first switching bridge and has a resonant inductor (L) connected in series. RA ) and resonant capacitor (C RA ) may be included. However, it is not necessarily limited thereto, and the first resonant tank may include a combination of at least one resonant inductor and at least one resonant capacitor connected in series or parallel.

[0107] The resonant converter (90) may include a second input-side circuit connected in parallel with the first input-side circuit and including a second switching bridge and a second resonant tank. In one embodiment, the second switching bridge may include a plurality of bridge switches (Q) controlled by at least one switching signal. 1B , Q 2B , Q 3B and Q 4B ) may be included. The second switching bridge may include a DC input voltage (V IN ) can generate a square wave output.

[0108] The second resonant tank is coupled to the second switching bridge and has a resonant inductor (L) connected in series. RB ) and resonant capacitor (C RB ) may be included. However, it is not necessarily limited thereto, and the second resonant tank may include a combination of at least one resonant inductor and at least one resonant capacitor connected in series or parallel.

[0109] Meanwhile, although Fig. 1 illustrates the first switching bridge and the second switching bridge as a full bridge configuration each including four bridge switches, this is not necessarily limited thereto. At least one of the first switching bridge and the second switching bridge may be a half bridge configuration including two bridge switches. In addition, at least one of the first switching bridge and the second switching bridge may be a full bridge configuration, but may operate in the same manner as a half bridge through control using a switching signal.

[0110] The resonant converter (90) may include a first output side circuit including a first rectifier network. The first rectifier network may include a plurality of bridge diodes (D) for converting an AC input into a DC output. R1A , D R2A , D R3A and D R4A ) may be included. In addition, the resonant converter (90) may include a second output-side circuit connected in parallel with the first output-side circuit and including a second rectifier network. The second rectifier network may include a plurality of bridge diodes (D) for converting an AC input into a DC output. R1B , D R2B , D R3B and D R4B ) may be included.

[0111] The resonant converter (90) may include a transformer network (910) that electrically and / or magnetically couples the first input-side circuit, the second input-side circuit, the first output-side circuit, and the second output-side circuit. Compared to the resonant converter (10) of FIG. 1, the resonant converter (90) may include a first transformer (T A ) and the second transformer (T B ) instead, it differs only in that it includes a transformer network (910).

[0112] Referring to FIG. 9B, the transformer network (910) may include a first transformer (LLC1) whose primary side is connected to the first input side circuit and the second input side circuit, respectively, and whose secondary side is connected to the first output side circuit. In addition, the transformer network (910) may include a second transformer (LLC2) whose primary side is connected to the first input side circuit and the second input side circuit, respectively, and whose secondary side is connected to the second output side circuit.

[0113] The first transformer (LLC1) may include a first equivalent transformer (T1) having a primary winding connected to a first input-side circuit and a secondary winding connected to a first output-side circuit, and a second equivalent transformer (T2) having a primary winding connected to a second input-side circuit and a secondary winding connected to the first output-side circuit. In other words, the first transformer (LLC1) may include primary windings cross-connected between the first input-side circuit and the second input-side circuit on the primary side, and may include series-connected secondary windings magnetically coupled to the primary windings on the secondary side.

[0114] The second transformer (LLC2) may include a third equivalent transformer (T3) having a primary winding connected to the first input-side circuit and a secondary winding connected to the second output-side circuit, and a fourth equivalent transformer (T4) having a primary winding connected to the second input-side circuit and a secondary winding connected to the second output-side circuit. In other words, the second transformer (LLC2) may include primary windings cross-connected between the first input-side circuit and the second input-side circuit on the primary side, and series-connected secondary windings magnetically coupled with the primary windings on the secondary side.

[0115] The resonant converter (90) is configured to electrically connect the secondary side of the first transformer (LLC1) and the secondary side of the second transformer (LLC2) in series with a switch (Q). A ), and an output capacitor (C) shared by the first output side circuit and the second output side circuitO1 ) can be included. Switch (Q A ) depending on whether the output capacitor (C) is open or closed. O1 ) can vary in the range of output voltage applied to the first transformer (LLC1) and the second transformer (LLC2). At this time, since the primary side configurations of the first transformer (LLC1) and the second transformer (LLC2) are interchanged with each other, a wide range of output voltages can be provided, while current balancing between the two power conversion circuits can be automatically achieved.

[0116] FIG. 10 is a block diagram of an electric vehicle charger according to one embodiment.

[0117] Referring to FIG. 10, the electric vehicle charger (100) may include an AC-DC converter (1010), an electric reservoir (1020), a DC-DC converter (1030), and a control unit (1040). However, the internal structure of the electric vehicle charger (100) is not limited to that illustrated in FIG. 10. Those skilled in the art will understand that, depending on the design of the electric vehicle charger (100), some of the hardware components illustrated in FIG. 10 may be omitted or new components may be added. For example, the electric vehicle charger (100) may further include a socket unit including terminals for electrically connecting an external device and the electric vehicle charger (100).

[0118] An electric vehicle charger (100) may refer to a rapid charger installed at an electric charging station, similar to a gasoline station. In one example, the electric vehicle charger (100) can charge an electric vehicle battery by more than 80% within one hour, and the charging capacity of the electric vehicle charger (100) may be 30 kW or more. However, this is not necessarily limited thereto.

[0119] The AC-DC converter (1010) may refer to a converter that converts AC power received from an external power source into DC power. For example, the AC-DC converter (1010) may convert AC power received from an external three-phase AC input power source into single-phase DC power. However, the present invention is not limited thereto. Instead of being directly connected to an external three-phase AC input power source, the AC-DC converter (1010) may be connected to an external three-phase AC input power source through a separate three-phase transformer, etc., thereby receiving single-phase AC power and converting it into DC power.

[0120] The electric reservoir (1020) can store direct current power received from the AC-DC converter (1010). The electric reservoir (1020) can act as a buffer during the process of transmitting power from the AC-DC converter (1010) to the DC-DC converter (1030). The electric reservoir (1020) can include one or more battery packs, but is not limited thereto. In one embodiment, power can be transmitted directly from the AC-DC converter (1010) to the DC-DC converter (1030) without passing through the electric reservoir (1020).

[0121] The DC-DC converter (1030) may refer to a converter that converts input DC power into DC power having a different voltage and outputs it. For example, the DC-DC converter (1030) may convert DC power received from the AC-DC converter (1010) or the electric reservoir (1020) into DC power having a different voltage. The DC-DC converter (1030) may be the resonant converter (10) of FIG. 1, the resonant converter (60) of FIG. 6, the resonant converter (70) of FIG. 7, the resonant converter (80) of FIG. 8, or the resonant converter (90) of FIG. 9.

[0122] The control unit (1040) is hardware that controls the overall operation of the electric vehicle charger (100). For example, the control unit (1040) can control the operation of the AC-DC converter (1010), the electric reservoir (1020), and the DC-DC converter (1030), as well as other components included in the electric vehicle charger (100).

[0123] The control unit (1040) includes at least one processor. The processor may be implemented as an array of multiple logic gates, or as a combination of a general-purpose microprocessor and a memory storing a program executable on the microprocessor. Furthermore, those skilled in the art will appreciate that the processor may be implemented using other types of hardware.

[0124] In one embodiment, the DC-DC converter (1030) may include a first input-side circuit including a first switching bridge, a first resonant tank, and a first primary winding. The DC-DC converter (1030) may also include a second input-side circuit connected in parallel with the first input-side circuit, the second input-side circuit including a second switching bridge, a second resonant tank, and a second primary winding. The DC-DC converter (1030) may include a first output-side circuit including a first secondary winding forming a first transformer together with the first primary winding, and a first rectifier network. The DC-DC converter (1030) may also include a second output-side circuit connected in parallel with the first output-side circuit, the second secondary winding forming a second transformer together with the second primary winding, and a second rectifier network.

[0125] The DC-DC converter (1030) may include a switch connecting the first secondary winding and the second secondary winding, and an output capacitor shared by the first output-side circuit and the second output-side circuit. Here, the first input-side circuit and the first output-side circuit may constitute a first power conversion circuit, and the second input-side circuit and the second output-side circuit may constitute a second power conversion circuit.

[0126] When the switch is opened, the first transformer and the second transformer are connected in parallel, and the DC-DC converter (1030) can output a DC output voltage by independent operation of the first power conversion circuit and the second power conversion circuit. In one embodiment, the first power conversion circuit and the second power conversion circuit can operate in an interleaved manner to reduce current ripple. However, this is not necessarily limited thereto.

[0127] When the switch is closed, the first transformer and the second transformer are connected in series, and the sum of the output voltage of the first output-side circuit and the output voltage of the second output-side circuit can be applied to the output capacitor.

[0128] In this way, the electric vehicle charger (100) according to the present disclosure can provide a wide range of output voltages using the DC-DC converter (1030). By arranging a switch between the secondary windings of the output circuits, the electric vehicle charger (100) can perform conversion between series connection and parallel connection of power conversion circuits with only a single switch. Accordingly, the space occupied by the circuit configuration for conversion between series connection and parallel connection within the power conversion system can be reduced. In addition, reliability can be increased compared to when multiple switches are used.

[0129] In other embodiments, the DC-DC converter (1030) may be a resonant converter (70) of FIG. 7, a resonant converter (80) of FIG. 8, or a resonant converter (90) of FIG. 9, and may reduce voltage / current stress of an equivalent transformer for delivering the same output power, reduce switching stress of bridge switches, or perform current balancing between power conversion circuits.

[0130] The description of the above-described embodiments is merely illustrative, and those skilled in the art will appreciate that various modifications and equivalent alternative embodiments are possible. Therefore, the true scope of protection for the invention should be defined by the appended claims, and all differences within the scope equivalent to the claims should be construed as being included within the scope of protection defined by the claims.

Claims

1. In a resonant converter for an electric vehicle charger, A first input side circuit including a first switching bridge, a first resonant tank, and a first primary winding; A second input side circuit connected in parallel with the first input side circuit and including a second switching bridge, a second resonant tank, and a second primary winding; A first output circuit including a first secondary winding constituting a first transformer together with the first primary winding, and a first rectifier network; A second output-side circuit including a second secondary winding connected in parallel with the first output-side circuit and forming a second transformer together with the second primary winding, and a second rectifier network; A first switch configured to electrically connect the first secondary winding and the second secondary winding in series; and A resonant converter comprising a first output capacitor shared by the first output side circuit and the second output side circuit.

2. In paragraph 1, The above first input side circuit and the above first output side circuit constitute a first power conversion circuit, The above second input side circuit and the above second output side circuit constitute a second power conversion circuit, When the above first switch is opened, The first transformer and the second transformer are connected in parallel, A resonant converter in which a DC output voltage is applied to the first output capacitor through independent operations of the first power conversion circuit and the second power conversion circuit.

3. In paragraph 2, A resonant converter in which the first power conversion circuit and the second power conversion circuit operate in an interleaved manner to reduce current ripple.

4. In paragraph 1, When the above first switch is closed, The first transformer and the second transformer are connected in series, A resonant converter in which the sum of the output voltage of the first output-side circuit and the output voltage of the second output-side circuit is applied to the first output capacitor.

5. In paragraph 1, A resonant converter, wherein each of the first switching bridge and the second switching bridge includes a plurality of bridge switches controlled by at least one switching signal, and generates a square wave output from a direct current input voltage.

6. In paragraph 1, The first resonance tank and the second resonance tank are respectively coupled to the first switching bridge and the second switching bridge, A resonant converter, wherein each of the first resonant tank and the second resonant tank includes a resonant inductor and a resonant capacitor connected in series.

7. In paragraph 1, A resonant converter in which each of the first transformer and the second transformer changes the strength of the AC voltage in proportion to the turns ratio between the primary winding and the secondary winding.

8. In paragraph 1, A resonant converter, wherein each of the first rectifier network and the second rectifier network includes a plurality of bridge diodes for converting an AC input into a DC output.

9. In paragraph 1, A resonant converter wherein the first switch is a single switching element.

10. In paragraph 1, A resonant converter, wherein the first switch comprises at least one of a metal-oxide-semiconductor field-effect transistor (MOSFET), a bipolar junction transistor (BJT), a gate turn-off thyristor (GTO), an integrated gate commutated thyristor (IGCT), an isolated gate bipolar transistor (IGBT), and a relay.

11. In paragraph 1, The above resonant converter, A third input side circuit including a third switching bridge, a third resonant tank and a third primary winding; A fourth input side circuit connected in parallel with the third input side circuit and including a fourth switching bridge, a fourth resonant tank, and a fourth primary winding; A third output side circuit including a third secondary winding forming a third transformer together with the third primary winding, and a third rectifier network; A fourth output circuit including a fourth secondary winding connected in parallel with the third output circuit and forming a fourth transformer together with the fourth primary winding, and a fourth rectifier network; A second switch configured to electrically connect the third secondary winding and the fourth secondary winding in series; and A resonant converter further comprising a second output capacitor shared by the third output side circuit and the fourth output side circuit.

12. In paragraph 11, The third input side circuit and the third output side circuit constitute a third power conversion circuit, The fourth input side circuit and the fourth output side circuit constitute a fourth power conversion circuit, When the above second switch is opened, The third transformer and the fourth transformer are connected in parallel, A resonant converter in which a DC output voltage is applied to the second output capacitor through independent operations of the third power conversion circuit and the fourth power conversion circuit.

13. In paragraph 11, When the above second switch is closed, The third transformer and the fourth transformer are connected in series, A resonant converter in which the sum of the output voltage of the third output-side circuit and the output voltage of the fourth output-side circuit is applied to the second output capacitor.

14. In paragraph 11, The first input side circuit and the second input side circuit are connected in parallel with the third input side circuit and the fourth input side circuit, A resonant converter, wherein the first output side circuit and the second output side circuit are connected in parallel with the third output side circuit and the fourth output side circuit.

15. In paragraph 11, The first input side circuit and the second input side circuit are connected in series with the third input side circuit and the fourth input side circuit, A resonant converter, wherein the first output side circuit and the second output side circuit are connected in parallel with the third output side circuit and the fourth output side circuit.

16. In a resonant converter for an electric vehicle charger, A first input side circuit including a first switching bridge and a first resonant tank; A second input side circuit connected in parallel with the first input side circuit and including a second switching bridge and a second resonant tank; A first output side circuit including a first rectifier network; A second output-side circuit connected in parallel with the first output-side circuit and including a second rectifier network; and A transformer network electrically and / or magnetically coupling the first input side circuit, the second input side circuit, the first output side circuit, and the second output side circuit, The above transformer network is, A first transformer, the primary side of which is connected to the first input side circuit and the second input side circuit, respectively, and the secondary side of which is connected to the first output side circuit, and A second transformer is included, the primary side being connected to the first input side circuit and the second input side circuit, respectively, and the secondary side being connected to the second output side circuit, The above resonant converter, A resonant converter further comprising a switch configured to electrically connect the secondary side of the first transformer and the secondary side of the second transformer in series.

17. In electric vehicle chargers, AC-DC converter that converts AC power received from an external power source into DC power; An electric reservoir for storing direct current power received from the AC-DC converter; A DC-DC converter that converts the DC power received from the AC-DC converter or the electric reservoir into DC power having a different voltage; and It includes a control unit that controls the AC-DC converter, the electric reservoir, and the DC-DC converter, The above DC-DC converter, A first input side circuit including a first switching bridge, a first resonant tank and a first primary winding; A second input side circuit connected in parallel with the first input side circuit and including a second switching bridge, a second resonant tank, and a second primary winding; A first output side circuit including a first secondary winding forming a first transformer together with the first primary winding, and a first rectifier network; A second output-side circuit including a second secondary winding connected in parallel with the first output-side circuit and forming a second transformer together with the second primary winding, and a second rectifier network; a switch connecting the first secondary winding and the second secondary winding; and An electric vehicle charger comprising an output capacitor shared by the first output side circuit and the second output side circuit.

18. In paragraph 17, The above first input side circuit and the above first output side circuit constitute a first power conversion circuit, The above second input side circuit and the above second output side circuit constitute a second power conversion circuit, When the above switch is opened, A resonant converter in which the first transformer and the second transformer are connected in parallel, and the DC-DC converter outputs a DC output voltage through independent operations of the first power conversion circuit and the second power conversion circuit.

19. In paragraph 18, A resonant converter in which the first power conversion circuit and the second power conversion circuit operate in an interleaved manner to reduce current ripple.

20. In paragraph 17, When the above switch is closed, The first transformer and the second transformer are connected in series, A resonant converter in which the sum of the output voltage of the first output-side circuit and the output voltage of the second output-side circuit is applied to the output capacitor.

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