Voltage conversion device and control method thereof, charging pile

Abstract

The embodiment of the application provides a voltage conversion device and a control method thereof and a charging pile, and belongs to the field of power control. The voltage conversion device comprises a first voltage module, a second voltage module and a switching module. The first voltage module comprises two first output ends. The second voltage module comprises two second output ends. The switching module comprises a plurality of switching devices. Each first output end is connected with two second output ends respectively, and a switching device is arranged between each first output end and two second output ends respectively. The voltage conversion device adopts four switching devices, so that the connection between each voltage module does not need to be rewired according to different scenes, and the voltage module with any output polarity can be flexibly connected in series or parallel.

Description

Technical Field

[0001] This application relates to the field of power control, and in particular to a voltage conversion device and its control method, and a charging pile. Background Technology

[0002] Different electric vehicle models may have different voltage platforms, meaning that the operating voltage of the electric vehicle battery system will vary. DC charging stations, as supporting facilities for electric vehicle charging, need to be compatible with different models. Furthermore, electric vehicles can also discharge into the grid, which requires DC charging stations to have V2G (Vehicle-to-Grid) functionality. Consequently, the input and output voltages of DC charging stations need to be adaptable to a wide range.

[0003] To meet the needs of DC charging piles, voltage conversion devices can be used in DC charging piles to broaden the voltage range by changing the series and parallel connection of each DC / DC (Direct Current to Direct Current) module. However, the output of each DC / DC module may be in phase or out of phase. Commonly used voltage conversion devices are usually only applicable to scenarios where the outputs of each DC / DC module are in phase, and cannot flexibly adapt to DC / DC modules with arbitrary output polarities. Summary of the Invention

[0004] This application provides a voltage conversion device and its control method, as well as a charging pile, to flexibly adapt to DC / DC modules with arbitrary output polarity.

[0005] In a first aspect, embodiments of this application provide a voltage conversion device, comprising:

[0006] A first voltage module, the first voltage module includes two first output terminals;

[0007] The second voltage module includes two second output terminals;

[0008] The switching module includes multiple switching devices, each of the first output terminals is connected to two second output terminals respectively, and a switching device is respectively disposed between each of the first output terminals and the two second output terminals.

[0009] In some embodiments, the apparatus further includes:

[0010] The third voltage module includes two third output terminals;

[0011] Each of the second output terminals is connected to one of the two third output terminals respectively, and a switching device is provided between each of the second output terminals and the two third output terminals respectively.

[0012] In some embodiments, the two first output terminals are respectively configured to output a first positive voltage and a first negative voltage, and the two second output terminals are respectively configured to output a second positive voltage and a second negative voltage.

[0013] When the first voltage module and the second voltage module are connected in series, the switching device connected to the first output terminal corresponding to the first negative voltage and the second output terminal corresponding to the second positive voltage is configured to be in a closed state, and the other switching devices are configured to be in an open state.

[0014] When the first voltage module and the second voltage module are connected in parallel, the switching devices connected to the first output terminal corresponding to the first positive voltage and the second output terminal corresponding to the second positive voltage, and the switching devices connected to the first output terminal corresponding to the first negative voltage and the second output terminal corresponding to the second negative voltage are all configured to be in a closed state, and the remaining switching devices are configured to be in an open state.

[0015] In some embodiments, the apparatus further includes:

[0016] Multiple bidirectional buffer modules are provided, and the multiple bidirectional buffer modules are correspondingly configured with multiple switching devices, with each bidirectional buffer module connected in parallel with the corresponding switching device;

[0017] In some embodiments, the bidirectional buffer module includes:

[0018] A bidirectional power device, one end of which is connected to one end of a corresponding switching device; the bidirectional power device includes a first switching transistor and a second switching transistor, wherein the second switching transistor is connected in series with the first switching transistor and the freewheeling direction is opposite.

[0019] A resistor, one end of which is connected to one end of the bidirectional power device;

[0020] A capacitor, one end of which is connected to the other end of the bidirectional power device and the other end of the resistor, and the other end of the capacitor is connected to the other end of the corresponding switching device.

[0021] In a second aspect, embodiments of this application provide a control method for a voltage conversion device, used to control the voltage conversion device as described in any of the first aspects, the method comprising:

[0022] The switching device that controls the first output terminal corresponding to the first negative polarity voltage and the second output terminal corresponding to the second positive polarity voltage is closed, while the other switching devices are open, so that the first voltage module and the second voltage module are connected in series.

[0023] Alternatively, the switching devices connected to the first output terminal corresponding to the first negative voltage and the second output terminal corresponding to the second negative voltage are closed, the switching devices connected to the first output terminal corresponding to the first positive voltage and the second output terminal corresponding to the second positive voltage are closed, and the remaining switching devices are open, so that the first voltage module and the second voltage module are connected in parallel.

[0024] In some embodiments, the method further includes:

[0025] The switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third positive voltage is closed, the switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third negative voltage is opened, the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third positive voltage is opened, and the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third negative voltage is opened, so that the second voltage module and the third voltage module are connected in series;

[0026] Alternatively, the switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third positive voltage can be opened, the switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third negative voltage can be closed, the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third positive voltage can be closed, and the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third negative voltage can be opened, so that the second voltage module and the third voltage module are connected in parallel.

[0027] In some embodiments, the method further includes:

[0028] Before controlling any of the switching devices to switch from a closed state to an open state, the first or second switching transistor of the corresponding bidirectional power device is turned on based on the direction of the current flowing through the switching device.

[0029] In some embodiments, the method further includes:

[0030] Before controlling any of the aforementioned switching devices to switch from the open state to the closed state, the first and second switching transistors of the corresponding bidirectional power device are disconnected.

[0031] Thirdly, embodiments of this application provide a charging pile, including a voltage conversion device as described in any of the first aspects.

[0032] The voltage conversion device of this application embodiment includes a first voltage module, a second voltage module, and a switching module. The first voltage module includes two first output terminals, the second voltage module includes two second output terminals, and the switching module includes multiple switching devices. Each first output terminal is connected to one of the two second output terminals, and a switching device is disposed between each first output terminal and each of the two second output terminals. This voltage conversion device uses four switching devices, which not only eliminates the need to rewire the connections between the voltage modules according to different scenarios, but also allows for flexible series-parallel switching of voltage modules with arbitrary output polarities. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0035] Figure 1 Here is an example structure of a voltage conversion device;

[0036] Figure 2 This is a schematic diagram of a voltage conversion device provided in an embodiment of this application;

[0037] Figure 3 for Figure 2 A schematic diagram of a voltage conversion device in one state is shown.

[0038] Figure 4 for Figure 2 Another schematic diagram of the voltage conversion device shown;

[0039] Figure 5 for Figure 2 Another schematic diagram of the voltage conversion device shown;

[0040] Figure 6 for Figure 2 Another schematic diagram of the voltage conversion device shown;

[0041] Figure 7 This is another structural schematic diagram of a voltage conversion device provided in an embodiment of this application;

[0042] Figure 8 This is a schematic diagram of the structure of the bidirectional buffer module provided in the embodiments of this application;

[0043] Figure 9 This is a schematic diagram of the overall flow of the control method for the voltage conversion device provided in the embodiments of this application.

[0044] Explanation of reference numerals in the attached figures:

[0045] 100 - First voltage module; 110 - First output terminal; 200 - Second voltage module; 210 - Second output terminal; 300 - Third voltage module; 310 - Third output terminal; 400 - Switching module; 410 - Switching device; 500 - Bidirectional buffer module; 510 - Bidirectional power device; 511 - First switching transistor; 512 - Second switching transistor; 520 - Resistor; 530 - Capacitor. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0047] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0048] In the embodiments of this application, "at least one" refers to one or more; "multiple" refers to two or more. In the description of this application, the terms "first," "second," "third," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance, nor should they be construed as indicating or implying order.

[0049] References such as “one embodiment” or “some embodiments” as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the terms “comprising,” “including,” “having,” and variations thereof, as used in this specification, mean “including, but not limited to,” unless otherwise specifically emphasized.

[0050] It should be noted that in the embodiments of this application, "and / or" describes the relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects before and after it are in an "or" relationship.

[0051] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0052] With the rapid development of the electric vehicle industry, 800V voltage platform models have become widespread, while 400V voltage platform models still have a certain number in use. DC charging piles, as supporting facilities for electric vehicle charging, need to be compatible with both types of models, thus requiring a wide output voltage range. To meet the needs of DC charging piles, using voltage conversion devices is an effective way to broaden the voltage range. This method can change only the connection method without altering the specific parameters and design of the voltage module.

[0053] DC charging piles typically consist of multiple DC / DC modules in their topology. However, the output of a DC / DC module can be either in phase or out of phase. In phase indicates that the output polarity is the same as the input, while out of phase indicates that the output polarity is opposite to the input. Examples of DC / DC modules with out-of-phase outputs include Buck-Boost converters and Cuk converters. Common voltage conversion devices are usually designed for scenarios where the outputs of all DC / DC modules are in phase, rarely addressing the case of out-of-phase outputs. Consequently, they cannot flexibly adapt to DC / DC modules with arbitrary output polarities.

[0054] As a preface to the embodiments of this application, please refer to Figure 1 , Figure 1This is an example structure of a voltage conversion device. The voltage conversion device includes a first voltage module 100 and a second voltage module 200. The first voltage module 100 includes two first output terminals 110, configured as a first positive terminal and a first negative terminal. The second voltage module 200 includes two second output terminals 210, configured as a second positive terminal and a second negative terminal. A first switch K1 is disposed between the first negative terminal and the second positive terminal, a second switch K2 is disposed between the first negative terminal and the second negative terminal, and a third switch K3 is disposed between the first positive terminal and the second positive terminal. When the first voltage module 100 and the second voltage module 200 need to be connected in series, the first switch K1 is closed, and the second switch K2 and the third switch K3 are open. When the first voltage module 100 and the second voltage module 200 need to be connected in parallel, the first switch K1 is open, and the second switch K2 and the third switch K3 are closed.

[0055] However, this voltage conversion device is only suitable for applications such as... Figure 1 The diagram illustrates the polarity distribution of the two output lines of the first voltage module 100 and the second voltage module 200. If the polarities of the two output lines of the second voltage module 200 are reversed—that is, if the first positive terminal outputs a positive voltage, the first negative terminal outputs a negative voltage, the second positive terminal outputs a negative voltage, and the second negative terminal outputs a positive voltage—the voltage conversion device cannot achieve a parallel connection between the first voltage module 100 and the second voltage module 200. Therefore, from the perspective of output polarity, this voltage conversion device imposes a restriction on the types of the first voltage module 100 and the second voltage module 200, prohibiting them from outputting opposite polarities.

[0056] In view of this, the present application provides a voltage conversion device that uses four switching devices 410 to connect the output terminals of two voltage modules. This not only eliminates the need to rewire the connections between the voltage modules according to different scenarios, but also allows for flexible series-parallel switching of voltage modules with arbitrary output polarity, thereby solving at least some of the above problems.

[0057] The specific implementation methods of this application are illustrated below through examples:

[0058] Please see Figure 2 , Figure 2This is a schematic diagram of a voltage conversion device provided in an embodiment of this application. The voltage conversion device includes a first voltage module 100, a second voltage module 200, and a switching module 400. The first voltage module 100 includes two first output terminals 110, and the second voltage module 200 includes two second output terminals 210. The switching module 400 includes a plurality of switching devices 410, each first output terminal 110 is connected to one of the two second output terminals 210, and a switching device 410 is respectively disposed between each first output terminal 110 and each of the two second output terminals 210.

[0059] The first voltage module 100 and the second voltage module 200 are used to output voltage, respectively. The first voltage module 100 and the second voltage module 200 represent two voltage modules arranged in sequence, that is, the first voltage module 100 can be connected in series or in parallel with the second voltage module 200 to change the voltage output.

[0060] For example, the first voltage module 100 can be one of a DC / DC module, a battery, and a supercapacitor 530, and the second voltage module 200 can be one of a DC / DC module, a battery, and a supercapacitor 530. The first voltage module 100 and the second voltage module 200 are of the same type. For ease of description, unless otherwise specified, the first voltage module 100 and the second voltage module 200 will be described using a DC / DC module as an example.

[0061] For example, the switching device 410 can be a single-channel switch or a relay, or other types of switches, which are not specifically limited in this application embodiment.

[0062] Specifically, the two first output terminals 110 are configured to output a first positive voltage V1+ and a first negative voltage V1-, respectively, and the two second output terminals 210 are configured to output a second positive voltage V2+ and a second negative voltage V2-, respectively. For ease of description, the two first output terminals 110 are defined as first output terminal 110a and first output terminal 110b, and the two second output terminals 210 are defined as second output terminal 210c and second output terminal 210d, respectively. The first output terminals 110a, 110b, 210c, and 210d are arranged sequentially along the first direction X. The switching device 410 between the first output terminal 110a and the second output terminal 210c is designated as S1, the switching device 410 between the first output terminal 110a and the second output terminal 210d is designated as S2, the switching device 410 between the first output terminal 110b and the second output terminal 210c is designated as S3, and the switching device 410 between the first output terminal 110b and the second output terminal 210d is designated as S4.

[0063] When the first voltage module 100 and the second voltage module 200 are connected in series, the switching device 410 connected to the first output terminal 110 corresponding to the first negative voltage V1- and the second output terminal 210 corresponding to the second positive voltage V2+ is configured to be in a closed state, and the remaining switching devices 410 are configured to be in an open state. When the first voltage module 100 and the second voltage module 200 are connected in parallel, the switching devices 410 connected to the first output terminal 110 corresponding to the first positive voltage V1+ and the second output terminal 210 corresponding to the second positive voltage V2+, and the switching devices 410 connected to the first output terminal 110 corresponding to the first negative voltage V1- and the second output terminal 210 corresponding to the second negative voltage V2- are all configured to be in a closed state, and the remaining switching devices 410 are configured to be in an open state.

[0064] Please see Figure 3 , Figure 3 for Figure 2 The diagram shows a state schematic of a voltage conversion device. In some examples, the first output terminal 110a is configured to output a first positive voltage V1+, the first output terminal 110b is configured to output a first negative voltage V1-, the second output terminal 210c is configured to output a second positive voltage V2+, and the second output terminal 210d is configured to output a second negative voltage V2-.

[0065] When the first voltage module 100 and the second voltage module 200 are connected in series, the switching device S3, which connects to the first output terminal 110b corresponding to the first negative voltage V1- and the second output terminal 210c corresponding to the second positive voltage V2+, is configured to be closed, while the remaining switching devices S1, S2, and S4 are configured to be open. At this time, the negative terminal of the first voltage module 100 is connected to the positive terminal of the second voltage module 200, and the entire voltage conversion device is in series. The total output voltage is the sum of the output voltages of the first voltage module 100 and the second voltage module 200.

[0066] Please see Figure 4 , Figure 4 for Figure 2 The diagram shows another state of the voltage conversion device. In other examples, the first output terminal 110a is configured to output a first positive voltage V1+, the first output terminal 110b is configured to output a first negative voltage V1-, the second output terminal 210c is configured to output a second positive voltage V2+, and the second output terminal 210d is configured to output a second negative voltage V2-.

[0067] When the first voltage module 100 and the second voltage module 200 are connected in parallel, the switching device S1, which connects to the first output terminal 110a corresponding to the first positive voltage V1+ and the second output terminal 210c corresponding to the second positive voltage V2+, and the switching device S4, which connects to the first output terminal 110b outputting the first negative voltage V1- and the second output terminal 210d outputting the second negative voltage V2-, are all configured to be in the closed state. The remaining switching devices S2 and S3 are configured to be in the open state. At this time, the negative terminal of the first voltage module 100 is connected to the negative terminal of the second voltage module 200, and the positive terminal of the first voltage module 100 is connected to the positive terminal of the second voltage module 200. The overall voltage conversion device is in parallel configuration.

[0068] Please see Figure 5 , Figure 5 for Figure 2 The diagram shows another state of the voltage conversion device. In some other examples, the first output terminal 110a is configured to output a first positive voltage V1+, the first output terminal 110b is configured to output a first negative voltage V1-, the second output terminal 210c is configured to output a second negative voltage V2-, and the second output terminal 210d is configured to output a second positive voltage V2+.

[0069] When the first voltage module 100 and the second voltage module 200 are connected in series, the switching device S4 connecting the first output terminal 110b and the second output terminal 210d is configured to be closed, and the other switching devices S1, S2 and S3 are configured to be open.

[0070] Please see Figure 6 , Figure 6 for Figure 2 The diagram shows another state of the voltage conversion device. In some other examples, the first output terminal 110a is configured to output a first positive voltage V1+, the first output terminal 110b is configured to output a first negative voltage V1-, the second output terminal 210c is configured to output a second negative voltage V2-, and the second output terminal 210d is configured to output a second positive voltage V2+.

[0071] When the first voltage module 100 and the second voltage module 200 are connected in parallel, the switching device S2 connected to the first output terminal 110a and the second output terminal 210d, and the switching device S3 connected to the first output terminal 110b and the second output terminal 210c are configured to be in the closed state, and the remaining switching devices S1 and S4 are configured to be in the open state.

[0072] Please see Figure 7 , Figure 7This is another structural schematic diagram of a voltage conversion device provided in an embodiment of this application. The voltage conversion device further includes a third voltage module 300, which includes two third output terminals 310; each second output terminal 210 is connected to the two third output terminals 310 respectively, and a switching device 410 is respectively provided between each second output terminal 210 and the two third output terminals 310.

[0073] The third voltage module 300 is used for output voltage. The first voltage module 100, the second voltage module 200, and the third voltage module 300 represent three voltage modules arranged in sequence. That is, the first voltage module 100 is connected in series or in parallel with the second voltage module 200, and the second voltage module 200 is connected in series or in parallel with the third voltage module 300. The first voltage module 100 and the third voltage module 300 are indirectly connected through the connection with the second voltage module 200.

[0074] For example, the third voltage module 300 can be one of a DC / DC module, a battery, or a supercapacitor 530. The first voltage module 100, the second voltage module 200, and the third voltage module 300 are of the same type. For ease of description, unless otherwise specified, the third voltage module 300 will be described using a DC / DC module as an example.

[0075] Specifically, the two third output terminals 310 are configured to output a third positive voltage V3+ and a third negative voltage V3-, respectively. For ease of description, the two third output terminals 310 are defined as third output terminal 310e and third output terminal 310f, and the first output terminal 110a, first output terminal 110b, second output terminal 210c, second output terminal 210d, third output terminal 310e, and third output terminal 310f are arranged sequentially along the first direction X. A switching device S5 is arranged between the second output terminal 210c and the third output terminal 310e, a switching device S6 is arranged between the second output terminal 210c and the third output terminal 310f, a switching device S7 is arranged between the second output terminal 210d and the third output terminal 310e, and a switching device S8 is arranged between the second output terminal 210d and the third output terminal 310f. In this way, no additional connection lines are needed between the first voltage module 100 and the third voltage module 300, which can save the number of switches, simplify the device structure, and enable more flexible switching.

[0076] When the first voltage module 100, the second voltage module 200, and the third voltage module 300 are connected in series, the switching device 410 connected to the first output terminal 110 corresponding to the first negative voltage V1- and the second output terminal 210 corresponding to the second positive voltage V2+, and the switching device 410 connected to the second output terminal 210 corresponding to the second negative voltage V2- and the third output terminal 310 corresponding to the third positive voltage V3+ are configured to be in a closed state, and the remaining switching devices 410 are configured to be in an open state.

[0077] When the first voltage module 100, the second voltage module 200, and the third voltage module 300 are connected in parallel, the switching device 410 connected to the first output terminal 110 corresponding to the first positive voltage V1+ and the second output terminal 210 corresponding to the second positive voltage V2+, the switching device 410 connected to the second output terminal 210 corresponding to the second positive voltage V2+ and the third output terminal 310 corresponding to the third positive voltage V3+, the switching device 410 connected to the first output terminal 110 corresponding to the first negative voltage V1- and the second output terminal 210 corresponding to the second negative voltage V2-, and the switching device 410 connected to the second output terminal 210 corresponding to the second negative voltage V2- and the third output terminal 310 corresponding to the third negative voltage V3- are all configured to be in the closed state, and the remaining switching devices 410 are configured to be in the open state.

[0078] It should be noted that the first voltage module 100, the second voltage module 200, and the third voltage module 300 represent three voltage modules arranged sequentially and interconnected by eight switching devices 410. The voltage conversion device of this application embodiment may also include more voltage modules, where the number of voltage modules n and the number of switching devices k satisfy: k = 4(n-1). For any two sequentially arranged voltage modules, the series-parallel switching configuration can be performed in the manner described in the foregoing embodiments for the first voltage module 100 and the second voltage module 200. Similarly, for any three sequentially arranged voltage modules, the series-parallel switching configuration can be performed in the manner described in the foregoing embodiments for the first voltage module 100, the second voltage module 200, and the third voltage module 300. This application embodiment does not specifically limit the number of voltage modules in the voltage conversion device; any scheme conforming to the concept of this application embodiment should fall within the protection scope of this application embodiment.

[0079] Please see Figure 8 , Figure 8This is a schematic diagram of the structure of the bidirectional buffer module 500 provided in an embodiment of this application. In some examples, the voltage conversion device in this embodiment of the application further includes multiple bidirectional buffer modules 500. The multiple bidirectional buffer modules 500 are correspondingly arranged with multiple switching devices 410, and each bidirectional buffer module 500 is connected in parallel with its corresponding switching device 410. In this way, the bidirectional buffer modules 500 can suppress voltage and current spikes during series-parallel switching, thereby extending the life of the switch contacts, reducing arc generation, protecting the load circuit, and significantly improving system reliability.

[0080] In some examples, the bidirectional buffer module 500 includes a bidirectional power device 510, a resistor 520, and a capacitor 530. One end of the bidirectional power device 510 is connected to one end of a corresponding switching device 410. One end of the resistor 520 is connected to one end of the bidirectional power device 510. One end of the capacitor 530 is connected to the other end of both the bidirectional power device 510 and the resistor 520, and the other end of the capacitor 530 is connected to the other end of the corresponding switching device 410.

[0081] For example, the bidirectional power device 510 may include a first switch 511 and a second switch 512, wherein the second switch 512 is connected in series with the first switch 511 and the freewheeling direction is opposite.

[0082] Specifically, the source of the first switching transistor 511 is connected to the source of the second switching transistor 512, the drain of the first switching transistor 511 is connected to one end of the corresponding switching device 410, the drain of the second switching transistor 512 is connected to one end of the capacitor 530, the conduction direction of the first body diode D1 included in the first switching transistor 511 is the second direction Y, and the conduction direction of the second body diode D2 included in the second switching transistor 512 is the first direction X, the first direction X is opposite to the second direction Y.

[0083] The buffering principle of the bidirectional buffer module 500 includes: detecting the direction of the current flowing through the corresponding switch device 410 when the switch device 410 is closed.

[0084] When switching device 410 needs to switch from a closed state to an open state, if the current flowing through the corresponding switching device 410 is in the first direction X, then the first switch 511 is turned on and the second switch 512 is turned off. At this time, the external power supply of switching device 410 will charge capacitor 530 through the first switch 511 and the second diode. The voltage across switching device 410 rises slowly, thereby avoiding voltage spikes across switching device 410 during the turn-off process. In the case where switching device 410 is a relay, its driving speed will be slower than the driving speed of the switching transistors. Therefore, the driving signals of the first switch 511 and the second switch 512 can be slightly earlier than the driving signal of switching device 410. That is, the first switch 511 and the second switch 512 are controlled to operate first, and then the switching device 410 is controlled to switch from a closed state to an open state.

[0085] When the switching device 410 needs to switch from the closed state to the open state, if the current flowing through the corresponding switching device 410 is in the second direction Y, the second switching transistor 512 will be turned on and the first switching transistor 511 will be turned off. At this time, the external power supply of the switching device 410 will charge the capacitor 530, and the voltage across the switching device 410 will rise slowly, thereby avoiding voltage spikes across the switching device 410 during the turn-off process.

[0086] When the switching device 410 needs to switch from the open state to the closed state, both the first switching transistor 511 and the second switching transistor 512 are turned off. At this time, the bidirectional power device 510 does not form a circuit, the capacitor 530 discharges through the resistor 520, and the resistor 520 plays a current-limiting role, thereby avoiding current spikes flowing through the switching device 410.

[0087] It is understood that the voltage conversion device in this application uses 4(n-1) switching devices 410 to connect the two output terminals of n voltage modules respectively. There are no restrictions on whether the output polarity of each voltage module is positive or negative, which can greatly expand the scope of application. It can realize the series and parallel application scenarios when the polarity of the output terminals of multiple voltage modules is consistent or inconsistent. Various DC / DC converter types can be plugged and played, and it has strong versatility and flexibility.

[0088] Accordingly, embodiments of this application also provide a control method for a voltage conversion device. Please refer to [link / reference]. Figure 9 , Figure 9 This is a schematic flowchart illustrating the overall process of the control method for the voltage conversion device provided in this application embodiment. The control method specifically includes the following steps:

[0089] Step 901: Control the switching device 410 connected to the first output terminal 110 corresponding to the first negative voltage and the second output terminal 210 corresponding to the second positive voltage to close, and the other switching devices 410 to open, so that the first voltage module 100 and the second voltage module 200 are connected in series.

[0090] Step 902: Control the switching device 410 connected to the first output terminal 110 corresponding to the first negative voltage and the second output terminal 210 corresponding to the second negative voltage to close, control the switching device 410 connected to the first output terminal 110 corresponding to the first positive voltage and the second output terminal 210 corresponding to the second positive voltage to close, and control the remaining switching devices 410 to open, so that the first voltage module 100 and the second voltage module 200 are connected in parallel.

[0091] In some embodiments, the control method further includes:

[0092] Step 903: Control the switching device 410 connecting the second output terminal 210 corresponding to the second negative voltage and the third output terminal 310 corresponding to the third positive voltage to close, open, and close the switching device 410 connecting the second output terminal 210 corresponding to the second negative voltage and the third output terminal 310 corresponding to the third negative voltage, so that the second voltage module 200 and the third voltage module 300 are connected in series.

[0093] Step 904: Control the switching device 410 connecting the second output terminal 210 corresponding to the second negative voltage and the third output terminal 310 corresponding to the third positive voltage to open, close, close, and open again, so that the second voltage module 200 and the third voltage module 300 are connected in parallel.

[0094] In this process, either step 901 or step 902 can be executed, and either step 903 or step 904 can be executed. There is no order restriction between steps 901, 902, 903 and 904.

[0095] In some embodiments, the control method further includes:

[0096] Before switching any of the switching devices 410 from the closed state to the open state, the first switch 511 or the second switch 512 of the corresponding bidirectional power device 510 is turned on based on the direction of the current flowing through the switching device 410. This avoids voltage spikes across the switching device 410 during the turn-off process.

[0097] In some embodiments, the control method further includes:

[0098] Before controlling any switching device 410 to switch from the open state to the closed state, the first switching transistor 511 and the second switching transistor 512 of the corresponding bidirectional power device 510 are disconnected. In this way, current spikes flowing through the switching device 410 during the closing process can be avoided.

[0099] It is understood that the control method of this application embodiment can flexibly switch between series and parallel connections for voltage modules of arbitrary output polarity without readjusting the wiring of the voltage conversion device, thereby greatly expanding the application scenarios.

[0100] Accordingly, this application also provides a charging pile, which includes the voltage conversion device described in the foregoing embodiment. In this way, the charging pile can flexibly switch between series and parallel connections of multiple voltage modules, thereby outputting different voltages, which greatly expands the voltage output range, flexibly realizes different voltage outputs, and can better adapt to vehicle models with different voltage platforms.

[0101] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although this application has disclosed preferred embodiments as above, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A voltage conversion device, characterized in that, The device includes: A first voltage module, the first voltage module includes two first output terminals; The second voltage module includes two second output terminals; The switching module includes multiple switching devices, each of the first output terminals is connected to two second output terminals respectively, and a switching device is respectively disposed between each of the first output terminals and the two second output terminals.

2. The voltage conversion device according to claim 1, characterized in that, The device further includes: The third voltage module includes two third output terminals; Each of the second output terminals is connected to one of the two third output terminals respectively, and a switching device is provided between each of the second output terminals and the two third output terminals respectively.

3. The voltage conversion device according to claim 1, characterized in that, The two first output terminals are respectively configured to output a first positive voltage and a first negative voltage, and the two second output terminals are respectively configured to output a second positive voltage and a second negative voltage; When the first voltage module and the second voltage module are connected in series, the switching device connected to the first output terminal corresponding to the first negative voltage and the second output terminal corresponding to the second positive voltage is configured to be in a closed state, and the other switching devices are configured to be in an open state. When the first voltage module and the second voltage module are connected in parallel, the switching devices connected to the first output terminal corresponding to the first positive voltage and the second output terminal corresponding to the second positive voltage, and the switching devices connected to the first output terminal corresponding to the first negative voltage and the second output terminal corresponding to the second negative voltage are all configured to be in a closed state, and the remaining switching devices are configured to be in an open state.

4. The voltage conversion device according to claim 1, characterized in that, The device further includes: Multiple bidirectional buffer modules are provided, and the multiple bidirectional buffer modules are correspondingly configured with multiple switching devices, with each bidirectional buffer module connected in parallel with the corresponding switching device.

5. The voltage conversion device according to claim 4, characterized in that, The bidirectional buffer module includes: A bidirectional power device, one end of which is connected to one end of a corresponding switching device; the bidirectional power device includes a first switching transistor and a second switching transistor, wherein the second switching transistor is connected in series with the first switching transistor and the freewheeling direction is opposite. A resistor, one end of which is connected to one end of the bidirectional power device; A capacitor, one end of which is connected to the other end of the bidirectional power device and the other end of the resistor, and the other end of the capacitor is connected to the other end of the corresponding switching device.

6. A control method for a voltage conversion device, characterized in that, The method for controlling the voltage conversion device as described in any one of claims 1-5 includes: The switching device that controls the first output terminal corresponding to the first negative polarity voltage and the second output terminal corresponding to the second positive polarity voltage is closed, while the other switching devices are open, so that the first voltage module and the second voltage module are connected in series. Alternatively, the switching devices connected to the first output terminal corresponding to the first negative voltage and the second output terminal corresponding to the second negative voltage are closed, the switching devices connected to the first output terminal corresponding to the first positive voltage and the second output terminal corresponding to the second positive voltage are closed, and the remaining switching devices are open, so that the first voltage module and the second voltage module are connected in parallel.

7. The control method for the voltage conversion device according to claim 6, characterized in that, The method further includes: The switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third positive voltage is closed, the switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third negative voltage is opened, the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third positive voltage is opened, and the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third negative voltage is opened, so that the second voltage module and the third voltage module are connected in series; Alternatively, the switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third positive voltage can be opened, the switching device connecting the second output terminal corresponding to the second negative voltage and the third output terminal corresponding to the third negative voltage can be closed, the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third positive voltage can be closed, and the switching device connecting the second output terminal corresponding to the second positive voltage and the third output terminal corresponding to the third negative voltage can be opened, so that the second voltage module and the third voltage module are connected in parallel.

8. The control method for the voltage conversion device according to claim 7, characterized in that, The method further includes: Before controlling any of the switching devices to switch from a closed state to an open state, the first or second switching transistor of the corresponding bidirectional power device is turned on based on the direction of the current flowing through the switching device.

9. The control method for the voltage conversion device according to claim 7, characterized in that, The method further includes: Before controlling any of the aforementioned switching devices to switch from the open state to the closed state, the first and second switching transistors of the corresponding bidirectional power device are disconnected.

10. A charging pile, characterized in that, Includes the voltage conversion device as described in any one of claims 1-5.

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