Charging system and control method thereof

Abstract

The invention relates to a charging system and a control method thereof. The charging system comprises a DC source; the direct-current bus is used for transmitting direct current obtained by converting electric energy of the alternating-current power grid or transmitting direct current output by the direct-current source; the charging host is used for outputting charging current to external equipment; the direct-current transformer is used for transforming the direct current transmitted by the direct-current bus and / or the direct current output by the direct-current source; the switching device has a first switching state and a second switching state; in the first switching state, the direct current source is electrically connected with the direct current bus through the switching device so as to realize electric energy transmission between the direct current bus and the direct current source; and in the second switching state, the direct current source is electrically connected with the charging host through the switching device so as to realize electric energy transmission between the direct current source and the charging host. According to the charging system and the control method thereof, electric energy transmission between the direct-current bus and the direct-current source or between the direct-current source and the charging host can be realized through the switching device, so that the energy conversion efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of charging technologies, and in particular, to a charging system and a control method thereof. Background Art

[0002] With the rapid development of the new energy industry, the penetration rate of new energy products (e.g., electric vehicles) is getting higher and higher, and the demand for energy (e.g., electric energy) is also increasing. To meet the electric energy demand of more electric vehicles, more charging piles need to be installed. A large number of charging piles are incorporated into a charging system (such as a charging system composed of an AC power supply branch, a photovoltaic power supply branch, and a pure energy storage power supply branch), which not only poses higher requirements for the safety of the charging system, but also poses higher requirements for the stability of the charging system. In the related art, the connection relationship between the AC power supply branch, the photovoltaic power supply branch, and / or the pure energy storage power supply branch in the charging system and the charging pile (or load) is relatively chaotic, and the system stability is poor. Summary of the Invention

[0003] Embodiments of this application provide a charging system and a control method thereof, which improve the energy conversion efficiency of the charging system to at least partially solve the above technical problems.

[0004] To achieve the above object, according to the first aspect of this application, a charging system is provided, including:

[0005] A DC power source;

[0006] A DC bus, which is used to transmit the direct current obtained by converting the electric energy of the AC power grid, or is used to transmit the direct current output by the DC power source;

[0007] A charging host, which is used to output a charging current to an external device;

[0008] A DC transformer, which is used to transform the direct current transmitted by the DC bus and / or the direct current output by the DC power source; and

[0009] A switching device, which has a first switching state and a second switching state;

[0010] Wherein, in the first switching state, the DC power source is electrically connected to the DC bus through the switching device, so as to realize the power transmission between the DC bus and the DC power source; in the second switching state, the DC power source is electrically connected to the charging host through the switching device, so as to realize the power transmission between the DC power source and the charging host.

[0011] Optionally, in some embodiments of this application, in the first switching state and the second switching state, the DC power source is connected to the same DC transformer.

[0012] Optionally, in some embodiments of the present application, the DC transformer includes:

[0013] A first type of DC transformer, electrically connected to the DC bus and the charging host; and

[0014] A second type of DC transformer, electrically connected to the DC bus, the charging host, and the DC source;

[0015] In the first switching state and the second switching state, the DC source is connected to the second type of DC transformer.

[0016] Optionally, in some embodiments of the present application, the switching device includes:

[0017] A first type of switching device for controlling the connection and disconnection between the second type of DC transformer and the charging host;

[0018] A second type of switching device for controlling the connection and disconnection between the second type of DC transformer and the DC bus.

[0019] Optionally, in some embodiments of the present application, in the first switching state and the second switching state, the on-off states of the first type of switching device and the second type of switching device are different.

[0020] Optionally, in some embodiments of the present application, the charging system further includes:

[0021] A current converter for converting the electrical energy of the AC power grid into direct current and outputting it to the DC bus.

[0022] Optionally, in some embodiments of the present application, the DC bus includes:

[0023] A first DC bus and a second DC bus, the first DC bus and the second DC bus are respectively electrically connected to some current converters, and the first DC bus and the second DC bus are respectively connected to some DC transformers.

[0024] Optionally, in some embodiments of the present application, the charging system further includes:

[0025] A first type of disconnecting device for enabling the DC bus to have a first power supply state and a second power supply state;

[0026] Wherein, in the first power supply state, the electrical energy transmission between the first DC bus and some DC transformers is realized, and the electrical energy transmission between the second DC bus and another part of the DC transformers is realized;

[0027] In the second power supply state, the power transmission between all DC transformers is realized through the first DC bus and the second DC bus together.

[0028] Optionally, in some embodiments of the present application, the connection line of the DC transformer to the DC bus includes:

[0029] The first type of connection line is electrically connected to the first DC bus;

[0030] The second type of connection line is electrically connected to the second DC bus;

[0031] The first connection end of the first type of disconnecting device is connected to the first type of connection line, and the second connection end is connected to the second type of connection line.

[0032] Optionally, in some embodiments of the present application, each of the first type of connection lines is only connected to one of the first type of disconnecting devices, and each of the second connection lines is also only connected to one of the first type of disconnecting devices.

[0033] Optionally, in some embodiments of the present application, the charging system further includes:

[0034] The second type of disconnecting device is used to control the connection and disconnection between the DC transformer and the first DC bus.

[0035] Optionally, in some embodiments of the present application, the charging system further includes:

[0036] The third type of disconnecting device is used to control the connection and disconnection between the DC transformer and the second DC bus.

[0037] Optionally, in some embodiments of the present application, the second type of disconnecting device is arranged on the connection line between the first connection end of the first type of disconnecting device and the first DC bus;

[0038] The third type of disconnecting device is arranged on the connection line between the second connection end of the first type of disconnecting device and the second DC bus.

[0039] Optionally, in some embodiments of the present application, the charging system further includes:

[0040] A power distributor, which is electrically connected to the DC transformer and the charging host, so as to distribute the direct current after being transformed by the DC transformer to the charging host.

[0041] According to the second aspect of the present application, a control method for a charging system is provided, including:

[0042] Control the switching device to the first switching state so that the DC bus can transmit electric energy to and from the DC source through the DC transformer;

[0043] Control the switching device to the second switching state so that the DC source can transmit electric energy to and from the charging host through the DC transformer.

[0044] Optionally, in some embodiments of the present application, control the first type of disconnection device to be in the open state, so that the DC bus is in the first power supply state, realizing the electric energy transmission between the first DC bus and some of the DC transformers, and the electric energy transmission between the second DC bus and another part of the DC transformers;

[0045] Control the first type of disconnection device to be in the closed state, so that the DC bus is in the second power supply state, realizing the electric energy transmission of all the DC transformers by the first DC bus and the second DC bus together.

[0046] Optionally, in some embodiments of the present application, control the second type of disconnection device to be in the closed state, and the first type of disconnection device and the third type of disconnection device to be in the open state, realizing the electric energy transmission between the first DC bus and some of the DC transformers, and interrupting the electric energy transmission between the second DC bus and another part of the DC transformers;

[0047] Control the third type of disconnection device to be in the closed state, and the first type of disconnection device and the second type of disconnection device to be in the open state, realizing the electric energy transmission between the second DC bus and some of the DC transformers, and interrupting the electric energy transmission between the first DC bus and another part of the DC transformers.

[0048] Optionally, in some embodiments of the present application, control the second type of disconnection device to be in the open state, and the first type of disconnection device and the third type of disconnection device to be in the closed state, so that the second DC bus can transmit electric energy to all the DC transformers alone;

[0049] Control the third type of disconnection device to be in the open state, and the first type of disconnection device and the second type of disconnection device to be in the closed state, so that the first DC bus can transmit electric energy to all the DC transformers alone.

[0050] The beneficial effect of the present application is that it provides a charging system and its control method that can improve the energy conversion efficiency by realizing the electric energy transmission between the DC bus and the DC source or between the DC source and the charging host through the switching device.

[0051] More specifically, some embodiments of the present application may produce the following specific beneficial effects:

[0052] The DC transformer is adopted to convert the DC power obtained from the DC bus and then output it to the charging host, and further output it to the load. Moreover, the DC power obtained from the DC bus can be converted in voltage and output to other DC sources, reducing the number of components in the charging system, simplifying the system circuit, and being beneficial to improving the system stability.

[0053] The switching device is adopted to enable the DC transformer to transmit the DC power of the DC source and the DC power of the DC bus to the charging host simultaneously, improving the charging power.

[0054] Other features and advantages of the present application will be described in detail in the following specific implementation section. Brief Description of the Drawings

[0055] To more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative efforts.

[0056] To more completely understand the present application and its beneficial effects, the following description will be made in conjunction with the drawings, where the same reference numerals represent the same parts in the following description.

[0057] Figure 1 It is a schematic diagram of the working principle of the charging system in an exemplary embodiment of the present application;

[0058] Figure 2 It is a schematic diagram of the working principle of an optional DC transformer in an exemplary embodiment of the present application;

[0059] Figure 3 It is a schematic diagram of the structure of an optional charging system in an exemplary embodiment of the present application;

[0060] Figure 4 It is a schematic diagram of the structure of another optional charging system in an exemplary embodiment of the present application;

[0061] Figure 5 It is a schematic diagram of the structure of yet another optional charging system in an exemplary embodiment of the present application.

[0062] Description of the Reference Numerals in the Drawings:

[0063] 100, AC power grid;

[0064] 200, DC source;

[0065] 300, DC bus; 310, First DC bus; 320, Second DC bus;

[0066] 400, Charging host;

[0067] 500, DC transformer; 510, First type of DC transformer; 520, Second type of DC transformer;

[0068] 600, Switching device; 610, First type of switching device; 620, Second type of switching device;

[0069] 700, Current converter;

[0070] 800, Disconnection device; 810, First type of disconnection device; 820, Second type of disconnection device; 830, Third type of disconnection device;

[0071] 900, Power distributor. Specific embodiments

[0072] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0073] Refer to Figure 1 As shown, according to the first aspect of the present application, a charging system is provided, including a DC power source 200, a DC bus 300, a charging host 400, a DC transformer 500, and a switching device 600.

[0074] Among them, the DC power source 200 is used to store electric energy; the DC bus 300 is used to transmit the direct current converted from the electric energy of the AC power grid 100 or to transmit the direct current output by the DC power source 200, the charging host 400 is used to output a charging current to an external device, the DC transformer 500 is used to transform the direct current transmitted by the DC bus 300 and / or the direct current output by the DC power source 200, and the switching device 600 has a first switching state and a second switching state.

[0075] Specifically, in the first switching state, the DC power source 200 is electrically connected to the DC bus 300 through the switching device 600, so as to realize the electric energy transmission between the DC bus 300 and the DC power source 200; in the second switching state, the DC power source 200 is electrically connected to the charging host 400 through the switching device 600, so as to realize the electric energy transmission between the DC power source 200 and the charging host 400.

[0076] The charging system of the present application branches for different power sources (DC source 200 and the DC source 200 obtained by converting the AC source) through the above solution, realizes the energy connection and distribution between different DC sources 200, reduces the number of components in the system, and improves the energy conversion efficiency.

[0077] Referring to Figure 2 As shown, in some embodiments of the present application, in the first switching state and the second switching state, the DC source 200 is connected to the same DC transformer 500. Specifically, the DC transformer 500 includes a first type of DC transformer 510 and a second type of DC transformer 520. Among them, the first type of DC transformer 510 is electrically connected to the DC bus 300 and the charging host 400, and the second type of DC transformer 520 is electrically connected to the DC bus 300, the charging host 400, and the DC source 200. In the first switching state and the second switching state, the DC source 200 is connected to the second type of DC transformer 520.

[0078] In this embodiment, the switching device 600 includes a first type of switching device 610 and a second type of switching device 620. Among them, the first type of switching device 610 is used to control the connection and disconnection between the second type of DC transformer 520 and the charging host 400, and the second type of switching device 620 is used to control the connection and disconnection between the second type of DC transformer 520 and the DC bus 300.

[0079] In some more specific examples, referring to Figure 3 As shown, the switching device 600 can be a switch. The first type of switching device 610 is Figure 3 switch S1 in Figure 3In the middle is switch S2. The first connection end of the second type of switching device 620 is connected to the connection line between the first type of switching device 610 and the DC transformer 500. In this way, when the DC transformer 500 has only two connection ends, one connection end of the DC transformer 500 can be reused, and when the DC transformer 500 has multiple connection ends, the second type of switching device 620 can be directly connected to the second type of DC transformer 520. In this embodiment, when S1 is closed and S2 is opened, the electric energy of the AC power grid 100 can be transmitted to the DC power source 200 through voltage conversion. When the required power of the charging host 400 is relatively low, this working condition is used. The AC power grid 100 supplies power to the charging host 400 through the first type of DC transformer 510 and supplies power to the DC power source 200 through the second type of DC transformer 520 at the same time; when S1 is opened and S2 is closed, the electric energy of the DC power source 200 can be transmitted to the charging host 400 through voltage conversion. When the required power of the charging host 400 is relatively high, this working condition is used. The AC power grid 100 supplies power to the charging host 400 through the first type of DC transformer 510, and the DC power source 200 supplies power to the charging host 400 through the second type of DC transformer 520. Through the above method, the convenient flow and storage of energy are realized, the working mode of the DC transformer 500 can be adjusted according to the requirements of the charging host 400, the connection mode is simple, and the number of DC transformers 500 is reduced.

[0080] It should be noted that in the first switching state and the second switching state, the on-off states of the first type of switching device 610 and the second type of switching device 620 are different. In some other states, the first type of switching device 610 and the second type of switching device 620 can also be in the off state. However, it should be noted that to avoid damaging the circuit, the first type of switching device 610 and the second type of switching device 620 cannot be turned on at the same time.

[0081] Through the above solution, the classification of the DC transformer 500 is realized in this application. The first type of DC transformer 510 is used to step down the direct current converted from the AC power grid 100 and output it to the charging host 400, and the second type of DC transformer 520 is used to charge the DC power source 200 through the DC bus 300, or the DC power source 200 supplies power to the charging host 400 through the second type of DC transformer 520. In some examples, the DC power source 200 can be a separate energy storage device, such as a battery, etc. The DC power source 200 can also be an energy storage device of a system with a power generation function such as a photovoltaic system. At this time, the DC power source 200 can also supply electric energy to the charging bus. This application realizes the energy connection and distribution between different DC power sources 200, reduces the number of devices in the system, and improves the energy conversion efficiency.

[0082] It should be noted that in the foregoing and following embodiments, the current transmitted from the AC power grid 100 to the DC bus 300 is converted from AC to DC through the current converter 700.

[0083] Referring to Figure 3 As shown, in some embodiments of the present application, multiple DC buses 300 can be provided. For Figure 3 example, the DC bus 300 can include a first DC bus 310 and a second DC bus 320. The first DC bus 310 and the second DC bus 320 are respectively electrically connected to part of the current converters 700, and the first DC bus 310 and the second DC bus 320 are respectively connected to part of the DC transformers 500. In this way, compared with one DC bus 300, the two DC buses 300 reduce the current during normal operation, which is beneficial to improving the system stability. In some alternative embodiments, the first DC bus 310 and the second DC bus 320 are respectively connected to half of the current converters 700, the first DC bus 310 and the second DC bus 320 are respectively connected to half of the first type of DC transformers 510, and the first DC bus 310 and the second DC bus 320 are respectively connected to half of the second type of DC transformers 520.

[0084] On this basis, in order to make the charging system of the present application have better stability and applicability, in some embodiments of the present application, the charging system further includes a disconnecting device for controlling the conduction and disconnection of the current in the system.

[0085] Specifically, referring to Figure 4 As shown, in some embodiments of the present application, the charging system includes a first type of disconnecting device 810 for enabling the DC bus 300 to have a first power supply state and a second power supply state. Among them, in the first power supply state, the power transmission between the DC bus 300 and part of the DC transformers 500 is realized through the first DC bus 310, and the power transmission between the DC bus 300 and another part of the DC transformers 500 is realized through the second DC bus 320; in the second power supply state, the power transmission between all the DC transformers 500 is realized through the first DC bus 310 and the second DC bus 320 together.

[0086] In this embodiment, specifically, the connection lines connecting the DC transformers 500 to the DC bus 300 include a first type of connection line and a second type of connection line. Among them, the first type of connection line is electrically connected to the first DC bus 310, the second type of connection line is electrically connected to the second DC bus 320, the first connection end of the first type of disconnecting device 810 is connected to the first type of connection line, and the second connection end is connected to the second type of connection line. It should be noted that each first type of connection line is only connected to one first type of disconnecting device 810, and each second type of connection line is also only connected to one first type of disconnecting device 810. More specifically, the first type of disconnecting device 810 can beFigure 4 The switches S3 and S4 therein. When there is a problem with the current converter 700 or maintenance is required, the switches S3 and S4 can be closed, and the two busbars are connected for operation to disconnect the problematic current converter 700 from the circuit. By this setting, the operating stability of the system can be improved.

[0087] Referring to Figure 5 As shown, in some embodiments of the present application, the disconnecting device further includes a second type of disconnecting device 820 and a third type of disconnecting device 830. Among them, the second type of disconnecting device 820 is used to control the connection and disconnection between the DC transformer 500 and the first DC busbar 310, and the third type of disconnecting device 830 is used to control the connection and disconnection between the DC transformer 500 and the second DC busbar 320.

[0088] In some embodiments of the present application, in order to enable the first DC busbar 310 or the second DC busbar 320 to transmit electric energy alone, the second type of disconnecting device 820 is arranged on the connection line between the first connection end of the first type of disconnecting device 810 and the first DC busbar 310, and the third type of disconnecting device 830 is arranged on the connection line between the second connection end of the first type of disconnecting device 810 and the second DC busbar 320. More specifically, the second type of disconnecting device 820 can be Figure 5 the switches S31 and S41 therein, and the third type of disconnecting device 830 can be Figure 5 the switches S32 and S42 therein.

[0089] Based on the above solution, in the first type of DC transformer 510, by disconnecting S31 and S3, the maintenance of the DC transformer 500 on the line where S31 is located can be realized. On this basis, if S32 is closed, the connection between the DC transformer 500 and the second DC busbar 320 can still be maintained; similarly, by disconnecting S3 and S32, the maintenance of the DC transformer 500 on the line where S32 is located can be realized. On this basis, if S31 is closed, the connection between the DC transformer 500 and the first DC busbar 310 can still be maintained. When there is a fault in the current converter 700 connected to the first DC busbar 310 in the system, all the S31 disconnecting devices connected to the first DC busbar 310 are disconnected, and the S3 and S32 disconnecting devices are closed. The non-faulty current converter 700 supplies energy through the second DC busbar 320, and all the DC transformers 500 can operate normally, improving the convenience of maintenance and the stability of the system.

[0090] Similarly, in the second type of DC transformer 520, when S1 is closed and S2 is open, that is, the DC source 200 charges the power distributor; when S1 is open and S2 is closed, close S4 and open S41 or S42, then the first DC bus 310 or the second DC bus 320 can charge the DC source 200 separately, improving the convenience of maintenance and the stability of the system.

[0091] It should be noted that in the above embodiment, the charging system further includes a power distributor, which is electrically connected to the DC transformer 500 and the charging host 400 to distribute the direct current after voltage transformation by the DC transformer 500 to the charging host 400.

[0092] According to the second aspect of the present application, a control method for a charging system is also provided, which is implemented based on the above charging system. Specifically, the method includes:

[0093] Control the switching device 600 to the first switching state so that the DC bus 300 realizes power transmission with the DC source 200 through the DC transformer 500;

[0094] Control the switching device 600 to the second switching state so that the DC source 200 realizes power transmission with the charging host 400 through the DC transformer 500.

[0095] Specifically, the method further includes:

[0096] Control the first type of disconnecting device 810 to be in the open state, so that the DC bus 300 is in the first power supply state, realizing power transmission between the first DC bus 310 and part of the DC transformers 500 and power transmission between the second DC bus 320 and another part of the DC transformers 500;

[0097] Control the first type of disconnecting device 810 to be in the closed state, so that the DC bus 300 is in the second power supply state, realizing power transmission from the first DC bus 310 and the second DC bus 320 to all the DC transformers 500 together.

[0098] In some embodiments of the present application, the method further includes:

[0099] Control the second type of disconnecting device 820 to be in the closed state, and the first type of disconnecting device 810 and the third type of disconnecting device 830 to be in the open state, realizing power transmission between the first DC bus 310 and part of the DC transformers 500, and interrupting power transmission between the second DC bus 320 and another part of the DC transformers 500;

[0100] Control the third type of disconnection device 830 to be in the closed state, and the first type of disconnection device 810 and the second type of disconnection device 820 to be in the open state, so as to realize the power transmission between the second DC bus 320 and part of the DC transformer 500, and to interrupt the power transmission between the first DC bus 310 and another part of the DC transformer 500.

[0101] In some embodiments of the present application, the method further includes:

[0102] Control the second type of disconnection device 820 to be in the open state, and the first type of disconnection device 810 and the third type of disconnection device 830 to be in the closed state, so that the second DC bus 320 transmits electric energy alone with all DC transformers 500;

[0103] Control the third type of disconnection device 830 to be in the open state, and the first type of disconnection device 810 and the second type of disconnection device 820 to be in the closed state, so that the first DC bus 310 transmits electric energy alone with all DC transformers 500.

[0104] In summary, the present application divides different power sources (DC sources 200 and DC sources converted from AC sources), and realizes the energy connection and distribution between different DC sources 200 through the classification of DC transformers 500 and the switching of the switching device 600, reducing the number of components in the system and improving the energy conversion efficiency; the connection method is simple, and convenient maintenance can be carried out through the conversion method of the disconnection device, improving the stability of the system and reducing the design cost.

[0105] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "" is two or more, unless otherwise clearly and specifically defined.

[0106] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0107] Among the embodiments, implementation manners and related technical features of the present application, they can be combined and replaced with each other without conflict.

[0108] The above are only the preferred embodiments of the present application and do not impose any formal restrictions on the present application. Although the present application has been described with emphasis on each embodiment, for the parts not detailed in a certain embodiment, reference can be made to the relevant embodiments of other embodiments. However, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A charging system, characterized in that, Comprising: A DC power source; A DC bus, which is used to transmit the DC power converted from the power of the AC power grid, or is used to transmit the DC power output by the DC power source; A charging host, which is used to output a charging current to an external device; A DC transformer, which is used to transform the DC power transmitted by the DC bus and / or the DC power output by the DC power source; And A switching device, which has a first switching state and a second switching state; Wherein, in the first switching state, the DC power source is electrically connected to the DC bus through the DC transformer and the switching device, so as to realize the power transmission between the DC bus and the DC power source; in the second switching state, the DC power source is electrically connected to the charging host through the DC transformer and the switching device, so as to realize the power transmission between the DC power source and the charging host.

2. The charging system according to claim 1, wherein In the first switching state and the second switching state, the DC power source is connected to the same DC transformer.

3. The charging system according to claim 2, wherein The DC transformer includes: A first type of DC transformer, which is electrically connected to the DC bus and the charging host; and A second type of DC transformer, which is electrically connected to the DC bus, the charging host and the DC power source; In the first switching state and the second switching state, the DC power source is connected to the second type of DC transformer.

4. The charging system according to claim 3, wherein The switching device includes: A first type of switching device, which is used to control the connection and disconnection between the second type of DC transformer and the charging host; A second type of switching device, which is used to control the connection and disconnection between the second type of DC transformer and the DC bus.

5. The charging system according to claim 4, wherein In the first switching state and the second switching state, the on-off states of the first type of switching device and the second type of switching device are different.

6. The charging system according to claim 1, wherein The charging system further includes: A current converter, which is used to convert the power of the AC power grid into DC power and output it to the DC bus.

7. The charging system according to claim 6, wherein The DC bus includes: A first DC bus and a second DC bus, the first DC bus and the second DC bus are respectively electrically connected to part of the current converters, and the first DC bus and the second DC bus are respectively connected to part of the DC transformers.

8. The charging system according to claim 7, wherein The charging system further includes: A first type of disconnecting device, which is used to make the DC bus have a first power supply state and a second power supply state; Wherein, in the first power supply state, the power transmission between the DC bus and part of the DC transformers is realized through the first DC bus, and the power transmission between the DC bus and another part of the DC transformers is realized through the second DC bus; In the second power supply state, the power transmission between all the DC transformers is realized through the first DC bus and the second DC bus together.

9. The charging system according to claim 8, wherein the connection line connecting the DC transformer to the DC bus includes: a first type of connection line electrically connected to the first DC bus; a second type of connection line electrically connected to the second DC bus; a first connection end of the first type of disconnecting device is connected to the first type of connection line, and a second connection end is connected to the second type of connection line.

10. The charging system according to claim 9, wherein each of the first type of connection lines is connected to only one of the first type of disconnecting devices, and each of the second type of connection lines is also connected to only one of the first type of disconnecting devices.

11. The charging system according to claim 8, wherein the charging system further includes: a second type of disconnecting device for controlling the connection and disconnection between the DC transformer and the first DC bus.

12. The charging system according to claim 11, wherein the charging system further includes: a third type of disconnecting device for controlling the connection and disconnection between the DC transformer and the second DC bus.

13. The charging system according to claim 12, wherein the second type of disconnecting device is disposed on the connection line between the first connection end of the first type of disconnecting device and the first DC bus; the third type of disconnecting device is disposed on the connection line between the second connection end of the first type of disconnecting device and the second DC bus.

14. The charging system according to any one of claims 1 to 13, wherein the charging system further includes: a power distributor electrically connected to the DC transformer and the charging host to distribute the direct current after being transformed by the DC transformer to the charging host.

15. A control method for a charging system, characterized in that, including: controlling the switching device to the first switching state to enable the DC bus to transmit electrical energy to and from the DC source through the DC transformer; controlling the switching device to the second switching state to enable the DC source to transmit electrical energy to and from the charging host through the DC transformer.

16. The control method according to claim 15, characterized in that including: controlling the first type of disconnecting device to be in the open state, so that the DC bus is in the first power supply state, realizing the electrical energy transmission between the first DC bus and some of the DC transformers and the electrical energy transmission between the second DC bus and some other DC transformers; controlling the first type of disconnecting device to be in the closed state, so that the DC bus is in the second power supply state, realizing the electrical energy transmission from the first DC bus and the second DC bus to all the DC transformers together.

17. The control method according to claim 16, wherein including: controlling the second type of disconnecting device to be in the closed state, and the first type of disconnecting device and the third type of disconnecting device to be in the open state, realizing the electrical energy transmission between the first DC bus and some of the DC transformers, and interrupting the electrical energy transmission between the second DC bus and some other DC transformers; controlling the third type of disconnecting device to be in the closed state, and the first type of disconnecting device and the second type of disconnecting device to be in the open state, realizing the electrical energy transmission between the second DC bus and some of the DC transformers, and interrupting the electrical energy transmission between the first DC bus and some other DC transformers.

18. The control method according to claim 17, wherein including: Control the second type of disconnecting device to be in the open state, and the first type and the third type of disconnecting devices to be in the closed state, so that the second DC bus can perform power transmission with all DC transformers alone; Control the third type of disconnecting device to be in the open state, and the first type and the second type of disconnecting devices to be in the closed state, so that the first DC bus can perform power transmission with all DC transformers alone.

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