Ac / dc converter for electric vehicle charging and control method thereof

Abstract

This invention relates to an AC / DC converter for an on-board charger (OBC). The AC / DC converter includes: a three-phase input, comprising three inputs (a, b, c); a single-stage dual-active bridge (DAB) circuit; and an auxiliary circuit. The auxiliary circuit includes two switching devices (R1, R2) and an energy storage device (C1); the auxiliary circuit includes at least two branches; each of the two branches includes one of the switching devices (R1, R2); at least one branch is connected to the input (a, b) which is a single-phase AC input; the other branch is connected to the input (c) which is not a single-phase AC input; the other branch includes the energy storage device (C1).

Description

Technical Field

[0001] This invention relates to the technical field of alternating current / direct current (AC / DC) converter technology suitable for charging electric vehicles (EVs).

[0002] In this respect, the present invention relates to an AC / DC converter for an on-board charger (OBC).

[0003] The present invention also relates to an OBC for electric vehicles, a charging station for electric vehicles, and an uninterruptible power supply (UPS) system.

[0004] In addition, the present invention also relates to an AC / DC power supply. Background Technology

[0005] Many local and national governments are promoting vehicle electrification in response to the urgent need for the transportation industry to reduce fossil fuel consumption and emissions of carbon dioxide and other greenhouse gases and harmful particulate matter. To help accelerate EV adoption, low-cost, high-power-density on-board chargers (OBCs) are in high demand. Furthermore, chargers with bidirectional power flow capabilities can enhance the functionality and value of vehicles by providing additional power.

[0006] Furthermore, more and more people want to shorten the charging time of electric vehicles, which means that the charging power of OBCs (On-Board Chargers) will become increasingly larger, and high-power OBCs require three-phase AC input. In areas without three-phase power distribution, charging with single-phase AC input is also necessary; therefore, OBCs need to be compatible with both three-phase and single-phase input. Summary of the Invention

[0007] In view of the above problems and drawbacks, the present invention aims to improve the current implementation.

[0008] The object of this invention is to provide an improved AC / DC conversion. In particular, the object of this invention is to provide a simpler AC / DC conversion that is compatible with both three-phase and single-phase inputs.

[0009] This objective is achieved through the independent claims. Modified implementations are given in the dependent claims. The claimed subject matter is not limited to implementations that merely address the pointed disadvantages.

[0010] According to one aspect of the present invention, an alternating current / direct current (AC / DC) converter for an on-board charger (OBC) is provided. The AC / DC converter includes: a three-phase input, comprising three inputs; a single-stage dual-active bridge (DAB) circuit; and an auxiliary circuit. The auxiliary circuit includes two switching devices and an energy storage device; the auxiliary circuit includes at least two branches; each of the two branches includes one of the switching devices; at least one branch is connected to an input that serves as a single-phase AC input; the other branch is connected to an input that does not serve as a single-phase AC input; the other branch includes the energy storage device.

[0011] In other words, the auxiliary circuit includes at least two branches. One of the branches is connected to an input used as a three-phase input. The other branch is connected to an input used as a single-phase input. One of the branches includes at least one of the energy storage device and the switching device. The other branch includes only one of the switching devices.

[0012] The AC / DC converter can be used in OBCs, charging stations for electric vehicles, uninterruptible power supplies (UPS), or AC / DC power supplies.

[0013] According to another aspect of the invention, an OBC (On-Board Control) for an electric vehicle is provided. The OBC includes the AC / DC converter. The AC / DC converter can be modified according to any of the alternative embodiments described below.

[0014] According to another aspect of the invention, a charging station for electric vehicles is provided. The charging station includes the AC / DC converter. The AC / DC converter can be modified according to any of the alternative embodiments described below.

[0015] According to another aspect of the present invention, a UPS system is provided, the UPS system including the AC / DC converter. The AC / DC converter may be modified according to any of the alternative embodiments described below.

[0016] According to another aspect of the invention, an AC / DC power supply is provided, the AC / DC power supply including the AC / DC converter. The AC / DC converter can be modified according to any of the alternative embodiments described below.

[0017] According to another aspect of the present invention, a control method for an AC / DC converter is provided. The control method can be executed for an AC / DC converter in an OBC, a charging station for an electric vehicle, a UPS, or an AC / DC power supply.

[0018] The AC / DC converter includes: a three-phase input, comprising three inputs; a single-stage dual-active bridge (DAB) circuit; and auxiliary circuitry having at least two branches, including two switching devices and an energy storage device. Alternatively or additionally, the AC / DC converter is configured and constructed according to one aspect of the invention. The AC / DC converter can be modified according to any of the alternative embodiments described below.

[0019] The method includes different method steps, which are performed based on the input of the connection and the switching state of the circuit of the AC / DC converter:

[0020] The method includes:

[0021] • Under three-phase AC input conditions,

[0022] The auxiliary circuit is operated such that the energy storage device does not participate in the operation of the circuit, and the switching device remains open.

[0023] The method includes:

[0024] • When the input voltage is converted to a single-phase AC input of the single-stage DAB circuit, and

[0025] • When the input voltage is at a high level,

[0026] The auxiliary circuit is operated such that the remaining circuitry of the single-stage DAB circuit connected to the energy storage device operates in a BUCK state, and energy is stored in the energy storage device.

[0027] The method includes:

[0028] • When the input voltage is converted to a single-phase AC input of the single-stage DAB circuit, and

[0029] • When the input voltage changes from a higher level to a lower level,

[0030] The auxiliary circuit is operated such that the remaining circuit of the single-stage DAB circuit connected to the energy storage device operates in BOOST state, and the energy storage device supplements the bus of the single-stage DAB circuit; the auxiliary circuit is operated such that when the input AC voltage crosses zero, the switching device switches to the operating state.

[0031] The method may include method steps based on features of any alternative embodiment of the AC / DC converter.

[0032] This invention provides a compatible solution for AC / DC converters with both single-phase and three-phase inputs, which can be implemented using very few components. In particular, this invention provides a simpler solution for AC / DC converters used in vehicle chargers, which is less prone to unwanted artifacts, such as unwanted oscillations. Furthermore, due to its lower complexity, it requires less maintenance.

[0033] The switching device ensures that, in single-phase input mode, the capacitor is always connected to the input that is not used in three-phase input mode. Therefore, the capacitor connected only in single-phase input mode is charged by the auxiliary circuit in single-phase input mode.

[0034] Furthermore, this invention eliminates the need for large capacitors even when bus voltage ripple exists in a large single-phase AC input. Additionally, inductors and bidirectional switching devices (e.g., bidirectional switching transistors) can be used to achieve single-stage AC input compatibility.

[0035] The provided solution enables higher power density at a lower cost, while also facilitating the packaging of the AC / DC converter. Furthermore, compared to existing technologies, this invention offers a more efficient and better customized solution for power converters in electric vehicle (EV) applications.

[0036] The proposed solution provides an AC / DC converter for a low-cost, high-power-density on-board charger (OBC). The on-board charger has bidirectional power flow capability, which can enhance the functionality and value of electric vehicles by providing additional charging capacity.

[0037] Furthermore, the improved AC / DC converter is compatible with both single-phase and three-phase inputs, which can shorten the charging time of electric vehicles. Additionally, the OBC can also be used in locations without three-phase power distribution, where single-phase AC input charging is possible.

[0038] Optionally, the auxiliary circuit may include three branches. Two branches may each be connected to the input that serves as the single-phase AC input, while the other branch, including the energy storage device, may be connected to the input that is not the single-phase AC input. With respect to the voltage phase of the single-phase input, the auxiliary circuit with three connections can achieve a more even load distribution across the DAB module. This, in turn, means less impact on the components, thereby reducing the maintenance complexity of the entire AC / DC converter.

[0039] Optionally, the auxiliary circuit can be configured to connect to the input using two or three branches, such that in the case of a three-phase AC input, the energy storage device does not participate in the operation of the circuit, and the switching device remains open. This feature makes the auxiliary circuit not operate in the three-phase input mode. In other words, in the three-phase input mode, the DAB behaves as if the auxiliary circuit is not connected at all. This has the advantages that in the three-phase input mode, there is no additional load, and even less likely to occur unwanted artifacts such as vibration.

[0040] Optionally, the auxiliary circuit can be configured to connect to the input using two or three branches, such that...

[0041] • When the input voltage is converted to a single-phase AC input of the single-stage DAB circuit, and

[0042] • When the input voltage is at a high level,

[0043] The remaining circuitry of the single-stage DAB circuit connected to the energy storage device operates in a BUCK state, and energy is stored in the energy storage device. This is especially true for high-voltage scenarios. In this case, the remaining circuitry operates similarly to an equivalent BUCK circuit. This is a circuit capable of step-down functionality, but it is not simply equivalent to a Buck circuit. For the above single-stage DAB topology, a bus capacitor is not required when using a three-phase input. Instead, a storage capacitor is used to store energy.

[0044] Optionally, the auxiliary circuit can be configured to connect to the input using two or three branches, such that...

[0045] • When the input voltage is converted to a single-phase AC input of the single-stage DAB circuit, and

[0046] • When the input voltage changes from a higher level to a lower level,

[0047] The remaining circuitry of the single-stage DAB circuit connected to the energy storage device operates in BOOST mode, and the energy storage device supplements the bus of the single-stage DAB circuit. This refers to a low-voltage scenario. In this case, the remaining circuitry operates similarly to an equivalent BOOST circuit. In other words, in the second stage, when the voltage drops or is at a low level, the capacitor feeds the DAB. Therefore, the DAB can always operate as if fed by a three-phase input.

[0048] Optionally, the auxiliary circuit can be configured to connect to the input using two or three branches, such that the switching device switches to the operating state when the input AC voltage crosses zero. This refers to the zero-crossing voltage scenario. Due to the periodicity of the voltage in single-phase input mode, periodic switching of the switch can be ensured, and thus periodic charging and discharging of the capacitor can be guaranteed. The capacitor capacity is then selected according to the expected voltage load.

[0049] Optionally, each of the switching devices and the energy storage device can be connected in parallel. This design is particularly advantageous when there are three branches. Combined with the use of three branches, this design allows for more even distribution of the DAB's components.

[0050] Optionally, the first switching device and the storage device can be connected in series, and the second switching device can be connected in parallel with the first switching device and the storage device. The energy storage device may include multiple capacitors. Energy can be stored in the capacitors. When the input voltage drops, the capacitors can release energy. This alternative embodiment can be applied to two branches or three branches. In the case of three branches, two capacitors can be used, for example, the first capacitor is always connected to the input for three-phase mode, and the other capacitor (depending on the voltage phase) is connected to the input for both single-phase and three-phase modes. In single-phase input modes with strong voltage rise / fall and extremely large voltage peaks, it may be useful to use an auxiliary circuit with two branches and a capacitor with a high selectivity capacitance corresponding to the voltage peak.

[0051] Optionally, the switching device can be a switching transistor; and / or the energy storage device can be a capacitor. The inductor and bidirectional switching transistor in the original circuit can be used to achieve single-stage AC input compatibility. The advantage of using switching transistors and capacitors is that they are robust, durable, and low-maintenance components.

[0052] Optionally, the auxiliary circuit for the method may include at least one feature of the optional embodiments described above.

[0053] These and other aspects of the invention will become apparent from and will be elucidated in conjunction with the embodiments described below. The various features disclosed in the embodiments may individually or in combination constitute an aspect of the invention. Features of different embodiments may be transferred from one embodiment to another. Attached Figure Description

[0054] The following description of specific embodiments, in conjunction with the accompanying drawings, illustrates various aspects and implementations of the present invention, wherein:

[0055] Figure 1A simplified AC / DC converter circuit provided in one embodiment is illustrated schematically;

[0056] Figure 2 schematically shown Figure 1 The embodiments described above provide a simplified AC / DC converter circuit, a voltage curve, and a current in the first voltage phase marked on the voltage curve.

[0057] Figure 3 schematically shown Figure 1 The embodiments described above provide a simplified AC / DC converter circuit, a voltage curve, and the current in the second voltage phase marked on the voltage curve.

[0058] Figure 4 A simplified AC / DC converter circuit and voltage curve provided by another embodiment are schematically shown, wherein a first voltage phase is marked in the voltage curve;

[0059] Figure 5 A simplified AC / DC converter circuit and voltage curve provided by the other embodiment are schematically shown, wherein a second voltage phase is marked in the voltage curve;

[0060] Figure 6 A flowchart of a control method provided in one embodiment is shown. Detailed Implementation

[0061] Figure 1 A simplified AC / DC converter circuit according to one embodiment is illustrated schematically. The AC / DC converter circuit is suitable for both three-phase input mode and single-phase input mode. Depending on the capability of the three-phase input mode, the circuit provides three inputs (a, b, c); for the capability of the single-phase input mode, inputs a and b of the circuit can be used.

[0062] The circuit includes three inputs (a, b, c). The inputs (a, b, c) are connected to a single-stage dual-active bridge (DAB) circuit. The DAB circuit includes an energy transfer device E. A voltage Up is applied to one side of the energy transfer device E, i.e., to the inputs (a, b, c). A voltage Us is applied to the other side of the energy transfer device E. On one side of the energy transfer device E, multiple switching devices Q1 to Q6 and an inductor L are provided; on the other side of the energy transfer device E, multiple switching devices S1 to S4 and an energy storage device C2 are provided, where the energy storage device C2 is a capacitor in this exemplary embodiment. The output of the DAB circuit is an output voltage Vout, and the energy transfer device E is connected to the output voltage Vout via output lines (d, e). Each input of the DAB circuit is connected to its respective input (a, b, c) via inductors (La, Lb, Lc).

[0063] In addition to the DAB circuit, the AC / DC converter circuit also includes an auxiliary circuit. The auxiliary circuit includes two switching devices (R1, R2) and an energy storage device C1, which is a capacitor in this exemplary embodiment. The auxiliary circuit includes three branches.

[0064] Each of the two branches includes one of the switching devices (R1, R2). In the exemplary embodiment, the switching devices (R1, R2) are switching transistors. The third branch includes an energy storage device C1. The two branches including the switching devices (R1, R2) are each connected to one of the inputs (a, b), each of which serves as a single-phase AC input. The third branch including the energy storage device C1 is connected to an input c that is not used as a single-phase AC input. This input c is used in three-phase mode.

[0065] The operating mode of the AC / DC converter depends on the voltage phase and whether it operates in single-phase mode (i.e., using two inputs a and b) or three-phase mode (i.e., using all three inputs a, b, and c). The following text combines... Figures 1 to 3 Explain the working mode.

[0066] With a three-phase alternating current (AC) input, this means using all three inputs a, b, and c, with the switching transistor disconnected from inputs a and b. Therefore, the energy storage device C1 is not connected to any circuit.

[0067] In the case of single-phase AC input, this means that using inputs a and b, the single-phase AC is connected to terminals a and b.

[0068] When the potential of input a is higher than the potential of input b, switch R1 closes and switch R2 opens. In this voltage phase, C1 is connected to inputs b and c. When the potential of input b is higher than the potential of input a, switch R2 closes and switch R1 opens. In this voltage phase, C1 is connected to inputs a and c.

[0069] Figure 2 schematically shown Figure 1 The embodiments described above provide a simplified AC / DC converter circuit, a voltage curve, and a current in the first voltage phase marked on the voltage curve. Figure 3 schematically shown Figure 1 The embodiment described provides a simplified AC / DC converter circuit, voltage graphs, and the current in the second voltage phase marked on the voltage graphs. These two graphs show the case where the potential of input b is higher than the potential of input a, and switching device R2 is closed while switching device R1 is open. In this voltage phase, C1 is connected to inputs a and c.

[0070] The switching phase of R2 is closed, and the potential of input a is higher than the potential of input b, corresponding to the voltage phase indicated by the index letter "Vab" in the voltage curve plotted over time t / s, such as... Figure 2 The circuit above is shown. In this voltage phase, the energy storage device C1 is connected to inputs a and c.

[0071] When Vab is high, switching devices Q5, Q6, and Q4 are activated, and energy is stored in energy storage device C1 (see [link]). Figure 2 The arrows drawn in the middle indicate the current in the circuit.

[0072] When the switching phase of R2 is closed and Vba is low (see the voltage phase indicated by the index letter "Vba" in the voltage curve plotted over time t / s), as shown... Figure 3 When the circuit above is shown, the energy stored in the energy storage device C1 is transferred to the main power supply circuit through terminals a and c corresponding to inputs a and c (see above). Figure 3 The arrows drawn in the middle indicate the current in the circuit.

[0073] Similar to the above, the AC / DC converter circuit operates with switch R1 closed and switch R2 open: when Vab is high, energy is stored in energy storage device C1. When Vba is low, the energy stored in energy storage device C1 is transferred to the main power supply circuit through inputs b and c.

[0074] In the case of single-phase AC input, switching devices R1 and R2 switch their states when the AC voltage crosses zero (see [reference]). Figure 2 and Figure 3(Voltage curve plotted over time t / s).

[0075] Figure 4 A simplified AC / DC converter circuit and voltage curve provided by another embodiment are schematically shown, wherein a first voltage phase is marked in the voltage curve; Figure 5 A simplified AC / DC converter circuit and voltage curve provided by the other embodiment are schematically shown, wherein a second voltage phase is marked in the voltage curve.

[0076] This circuit is similar to the circuit described according to the first embodiment. The auxiliary circuit provided in the second embodiment differs from the auxiliary circuit provided in the first embodiment. This auxiliary circuit includes two switching devices (R1, R2) and an energy storage device C1. Furthermore, this auxiliary circuit includes two branches. One of the branches includes the switching device R1, and the other of the two branches includes the energy storage device C1 and the switching device R2. The branch including the switching device R1 is connected to input b, which is a single-phase AC input. The other branch is connected to input c, which is not a single-phase AC input. Input c is a three-phase AC input. The branch including the switching device R1 is also connected to ground N.

[0077] Figure 4 The circuit provided in the embodiment has the same Figures 1 to 3 The embodiments provide circuitry with similar functionality. For example... Figure 4 and Figure 5 The voltage curve plotted over time t / s shows that the voltage phase of the circuit is related to the voltage phase during operation. Figure 2 and Figure 3 The voltage phases shown in the voltage curves are different. Although Figures 1 to 3 The first embodiment provides a circuit with a voltage phase that is uniformly distributed over time, meaning that the two switching devices (R1, R2) operate within equal time intervals. Figure 4 and Figure 5 The second embodiment provides a circuit with a voltage phase that is non-uniformly distributed over time, meaning that the first switching device R1 operates within a different time interval than the second switching device R2. Specifically, the first switching device R1 operates within the voltage range indicated by the index letter "Vab", and the second switching device R2 operates within a shorter voltage range indicated by the index letter "Vba".

[0078] Figure 6A flowchart of a control method provided in one embodiment is shown. The method is a control method for an AC / DC converter. The AC / DC converter can be configured and constructed according to any of the above embodiments. The AC / DC converter includes at least: a three-phase input, including three inputs (a, b, c); a single-stage dual-active bridge (DAB) circuit; and an auxiliary circuit having at least two branches, including two switching devices (R1, R2) and an energy storage device C1.

[0079] According to the steps indicated by reference numeral "100" in the attached drawing, the method includes: operating the auxiliary circuit in the case of a three-phase AC input such that the energy storage device C1 does not participate in the operation of the circuit, and the switching devices (R1, R2) remain open.

[0080] According to the steps indicated by reference numeral "200" in the accompanying drawings, the method includes: when the input voltage of inputs (a, b, c) is converted to a single-phase AC input of the single-stage DAB circuit, and when the input voltage is at a higher level,

[0081] The auxiliary circuit is operated such that the remaining circuit of the single-stage DAB circuit connected to the energy storage device C1 operates in a BUCK state, and energy is stored in the energy storage device C1.

[0082] According to the steps indicated by reference numeral "300" in the accompanying drawings, the method includes: when the input voltage of the input (a, b, c) is converted to a single-phase AC input of the single-stage DAB circuit, and when the input voltage changes from a higher level to a lower level, operating the auxiliary circuit such that the remaining circuit of the single-stage DAB circuit connected to the energy storage device C1 operates in a BOOST state, and the energy storage device C1 supplements the bus of the single-stage DAB circuit.

[0083] According to the steps indicated by reference numeral "400" in the accompanying drawings, the method includes: operating the auxiliary circuit such that when the input AC voltage crosses zero, the switching devices (R1, R2) switch to the operating state.

[0084] This invention has been described in conjunction with various implementation methods.

[0085] However, those skilled in the art, through practice of the invention and study of the accompanying drawings, the invention itself, and the appended claims, can understand and obtain other variations of the disclosed implementation. In the claims, the word "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude multiple. A single processor or other unit can implement the functions of several items listed in the claims. Listing certain measures in dissimilar dependent claims does not imply that combinations of these measures cannot be effectively used. The computer program can be stored / distributed on suitable media, such as optical storage media or solid-state media provided with or as part of other hardware, and can also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

[0086] List of icon numbers

[0087] Input a, b, c

[0088] d, e output lines

[0089] E Energy Transmission Device

[0090] L Inductor

[0091] N location

[0092] C1 Energy Storage Device

[0093] C2 Energy Storage Device

[0094] Components of the N1 energy transfer device

[0095] Components of N2 energy transmission device

[0096] R1 Switching Device

[0097] R2 Switching Device

[0098] S1-S4 switching devices

[0099] Q1-Q6 Switching Device

[0100] Components of Lm energy transmission device

[0101] Vab voltage phase

[0102] Vba voltage phase

[0103] Vout output voltage

[0104] 100. Operate the auxiliary circuit such that the energy storage device does not participate in the operation of the circuit, and the switching device remains open.

[0105] 200 When the input voltage of the input is converted to a single-phase AC input of the single-stage DAB circuit, and when the input voltage is at a higher level, the auxiliary circuit is operated such that the remaining circuit of the single-stage DAB circuit connected to the energy storage device operates in a BUCK state, and energy is stored in the energy storage device.

[0106] 300 When the input voltage is converted to a single-phase AC input of the single-stage DAB circuit, and when the input voltage changes from a higher level to a lower level, the auxiliary circuit is operated such that the remaining circuit of the single-stage DAB circuit connected to the energy storage device operates in BOOST state, and the energy storage device supplements the bus of the single-stage DAB circuit.

[0107] 400 Operate the auxiliary circuit such that when the input AC voltage crosses zero, the switching device switches to the working state.

Claims

1. An AC / DC converter for a vehicle charger, characterized by, The AC / DC converter includes: Three-phase AC input, including input a, input b and input c; Single-stage dual active bridge circuit; Auxiliary circuit, The auxiliary circuit includes switching device R1, switching device R2, and energy storage device (C1). The auxiliary circuit includes at least two branches. Each of the two branches includes one of the switching devices R1 and R2. At least one branch is connected to either input a or input b, which is a single-phase AC input. The other branch is connected to the input c, which is not used as a single-phase AC input. The other branch includes the energy storage device (C1).

2. The AC / DC converter according to claim 1, characterized in that, The auxiliary circuit includes three branches. Each of the two branches is connected to input a and input b, which are the single-phase AC inputs. Another branch, including the energy storage device (C1), is connected to the input c, which is not used as the single-phase AC input.

3. The AC / DC converter according to claim 1, characterized in that, The auxiliary circuit is configured to use two or three branches to connect to input a, input b, or input c, such that in the case of three-phase AC input, the energy storage device (C1) does not participate in the operation of the circuit, and the switching devices R1 and R2 remain disconnected.

4. The AC / DC converter according to claim 1, characterized in that, The auxiliary circuit is configured to connect to input a, input b, or input c using two or three branches, such that... When the input voltage of input a, input b, or input c is converted to a single-phase AC input of the single-stage dual active bridge circuit, and When the input voltage is at a high level The remaining circuitry of the single-stage dual active bridge circuit connected to the energy storage device (C1) operates in BUCK state, and energy is stored in the energy storage device (C1).

5. The AC / DC converter according to claim 1, characterized in that, The auxiliary circuit is configured to connect to input a, input b, or input c using two or three branches, such that... When the input voltages of input a, input b, and input c are converted to the single-phase AC input of the single-stage dual active bridge circuit, and When the input voltage changes from a higher level to a lower level The remaining circuitry of the single-stage dual active bridge circuit connected to the energy storage device (C1) operates in BOOST mode, and the energy storage device (C1) supplements the bus of the single-stage dual active bridge circuit.

6. The AC / DC converter according to claim 1, characterized in that, The auxiliary circuit is configured to use two or three branches to connect to input a, input b, or input c, such that when the input AC voltage crosses zero, the switching device R1 and the switching device R2 switch to the working state.

7. The AC / DC converter according to claim 1, characterized in that, Each of the switching devices R1 and R2 is connected in parallel with the energy storage device (C1).

8. The AC / DC converter according to claim 1, characterized in that, The switching device R2 and the storage device (C1) are connected in series. The switching device R1 is connected in parallel with the switching device R2 and the storage device (C1).

9. The AC / DC converter according to claim 1, characterized in that, The switching devices R1 and R2 are switching transistors; and / or The energy storage device is a capacitor.

10. An on-board charger for an electric vehicle, a charging station for an electric vehicle, an uninterruptible power supply (UPS) system, or an AC / DC power supply, characterized in that, Includes the AC / DC converter according to at least one of the preceding claims.

11. A control method for an AC / DC converter, characterized in that, The AC / DC converter includes: Three-phase AC input, including input a, input b and input c; Single-stage dual active bridge circuit; An auxiliary circuit having at least two branches, including switching device R1 and switching device R2 and an energy storage device (C1); or The AC / DC converter is configured and constructed according to the features of any one of claims 1 to 9 above; The method includes: In the case of the three-phase AC input, Operate the auxiliary circuit such that the energy storage device (C1) does not participate in the operation of the circuit, and the switching devices R1 and R2 remain disconnected; When the input voltage of input a, input b, or input c is converted to a single-phase AC input of the single-stage dual active bridge circuit, and When the input voltage is at a high level The auxiliary circuit is operated such that the remaining circuit of the single-stage dual active bridge circuit connected to the energy storage device (C1) operates in a BUCK state, and energy is stored in the energy storage device (C1). When the input voltage of input a, input b, or input c is converted to a single-phase AC input of the single-stage dual active bridge circuit, and When the input voltage changes from a higher level to a lower level The auxiliary circuit is operated such that the remaining circuit of the single-stage dual active bridge circuit connected to the energy storage device (C1) operates in BOOST state, and the energy storage device (C1) supplements the bus of the single-stage dual active bridge circuit. The auxiliary circuit is operated such that when the input AC voltage crosses zero, the switching devices R1 and R2 switch to the working state.

Images