Mobile fast charging system for electric vehicles based on DC microgrid

Abstract

The present application provides a mobile fast charging system for electric vehicles based on a DC microgrid, the system comprising: a DC power supply module; a DC cable connected to the DC power supply module to transmit the DC voltage output by the DC power supply module; a fast charging interface of a mobile charging pile arranged in the DC cable at preset intervals, so that the mobile charging pile is plugged into the fast charging interface and the DC voltage is used to charge the electric vehicle. The charging solution of the present application based on DC voltage power supply greatly reduces the amount of cables used, making the mobile charging solution that cannot be implemented under 380V AC power supply due to high cost feasible.

Description

Technical Field

[0001] The present application belongs to the technical field of mobile charging and relates to a charging system, and in particular to a mobile fast charging system for electric vehicles based on a DC microgrid. Background Art

[0002] With the increasing awareness of environmental protection and restrictions on traditional fuel vehicles, the penetration rate of electric vehicles continues to increase. In order to facilitate the charging of electric vehicles, the charging infrastructure industry has also attracted rapid development. However, the current expansion speed of charging infrastructure construction still lags behind the development speed of new energy vehicles. There is still a large gap in the energy replenishment of electric vehicles. Charging queues and electric and fuel vehicles occupying seats often occur at charging stations.

[0003] Although excessive construction of charging piles in the station can solve the problem of charging queues during busy hours, the demand for charging in the station is small during off-peak hours and the utilization rate of charging facilities is low, which will cause a waste of charging resources and extend the operating profit cycle of the charging station.

[0004] To solve problems like these, major car companies and charging pile manufacturers are constantly exploring newer and more reasonable charging methods, including mobile charging stations.

[0005] The mobile charging method is to meet the charging needs of electric vehicles, solve the problem of insufficient charging infrastructure construction, provide flexible charging services, improve public charging services, and promote the development of the electric vehicle industry. Summary of the invention

[0006] The present application provides a mobile fast charging system for electric vehicles based on a DC microgrid, which is used to solve the problem of how to provide a low-cost, more convenient and reasonable mobile charging solution.

[0007] In the first aspect, the present application provides a mobile fast charging system for electric vehicles based on a DC microgrid, the system comprising: a DC power supply module; a DC cable, connected to the DC power supply module, transmitting the DC voltage output by the DC power supply module; a fast charging interface of a mobile charging pile, arranged in the DC cable at preset intervals, so that the mobile charging pile can be plugged into the fast charging interface to charge the electric vehicle using the DC voltage.

[0008] In an implementation of the first aspect, the DC power supply module includes a transformer rectifier; an input end of the transformer rectifier is connected to three-phase alternating current, and the DC voltage is output after the three-phase alternating current is transformed and rectified.

[0009] In an implementation of the first aspect, the transformer-rectifier includes a transformer unit, a rectifier unit and a stabilizing capacitor; the rectifier unit is connected to the transformer unit and the stabilizing capacitor respectively; the transformer unit converts the input three-phase alternating current into a three-phase power supply that meets the charging requirements, the rectifier unit rectifies the three-phase power supply and outputs it to the stabilizing capacitor, and the stabilizing capacitor outputs the DC voltage.

[0010] In an implementation of the first aspect, the transformer unit includes a three-phase isolation transformer, and the rectifier unit includes a three-phase rectifier bridge.

[0011] In an implementation manner of the first aspect, the DC voltage includes an 800V DC voltage.

[0012] In an implementation of the first aspect, the system further includes: a mobile charging pile; the mobile charging pile is provided with a charging plug, and the charging plug is plugged and connected to the fast charging interface.

[0013] In an implementation of the first aspect, the mobile charging pile includes a DC conversion module, one end of which is connected to the charging plug, receives the DC voltage, performs DC conversion on the DC voltage, and outputs the charging voltage required for charging the electric vehicle from the other end.

[0014] In an implementation of the first aspect, the mobile charging pile includes a plurality of mobile charging piles configured with different power sizes.

[0015] In an implementation of the first aspect, the mobile charging pile includes a retractable cable of a preset length.

[0016] In an implementation of the first aspect, the DC cable is laid in a parking lot along a preset path, and the preset path is determined according to the distance between different DC cables and the location of parking spaces. The preset intervals of the fast charging interfaces on the DC cables are determined according to the number of parking spaces planned to be covered by a single fast charging interface.

[0017] As described above, the mobile fast charging system for electric vehicles based on DC microgrid described in this application has the following beneficial effects:

[0018] This application is based on a mobile fast charging solution powered by an 800V DC microgrid, which greatly reduces the use of cables and makes mobile charging solutions that are impossible to implement under 380V AC power supply due to high costs feasible.

[0019] Compared with traditional fixed charging piles, mobile charging solutions can effectively solve the problem of gasoline vehicles occupying charging parking spaces and electric vehicles occupying charging parking spaces when fully charged. There is no need to set up special charging parking spaces separately, which improves the utilization rate of parking spaces and charging piles and the operating efficiency of charging stations, and reduces the investment in charging equipment. Secondly, it solves many pain points of fixed charging pile charging scenarios. There is no need to queue for charging, and charging can basically be achieved as soon as the car stops, so users can get a senseless charging experience. For electric vehicles that require large-capacity charging, DC power supply can complete the charging process faster and meet users' needs for fast charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Shown is a schematic diagram of the structure of a mobile fast charging system for electric vehicles based on a DC microgrid as described in an embodiment of the present application.

[0021] Figure 2 Shown is a schematic diagram of the DC power supply of the mobile fast charging system for electric vehicles based on a DC microgrid as described in an embodiment of the present application.

[0022] Figure 3 Shown is a DC power supply schematic diagram of a DC microgrid-based mobile fast charging system for electric vehicles as described in an embodiment of the present application.

[0023] Figure 4 Shown is a mobile charging schematic diagram of a DC microgrid-based electric vehicle mobile fast charging system as described in an embodiment of the present application.

[0024] Figure 5 Shown is a schematic diagram of the charging pile structure of the mobile fast charging system for electric vehicles based on a DC microgrid as described in an embodiment of the present application.

[0025] Figure 6 Shown is a charging conversion schematic diagram of a DC microgrid-based electric vehicle mobile fast charging system as described in an embodiment of the present application.

[0026] Figure 7 Shown is a schematic diagram of the fast charging interface structure of the DC microgrid-based electric vehicle mobile fast charging system described in an embodiment of the present application.

[0027] Figure 8 Shown is a schematic diagram of the application structure of a mobile fast charging system for electric vehicles based on a DC microgrid as described in an embodiment of the present application.

[0028] Component number description

[0029] 1 DC power supply module

[0030] 11 Transformer unit

[0031] 12 Rectification unit

[0032] C1 Voltage stabilizing capacitor

[0033] 2 DC cables

[0034] 3 Fast charging port DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0036] It should be noted that the illustrations provided in the following embodiments are only used to illustrate the basic concept of the present application in a schematic manner, and therefore the illustrations only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0037] The technical solutions in the embodiments of the present application will be described in detail below in conjunction with the drawings in the embodiments of the present application.

[0038] The current mobile charging solutions are either based on mobile charging piles with energy storage or on laying 380V cables throughout the station. The energy storage-based solution is expensive and requires a fixed space to place and replenish the power of the energy storage device in the mobile charging pile, so this solution is difficult to promote. The solution based on 380V cables, due to the high power of the charging pile and the high current at the 380V input end, laying cables over a large area will bring unbearable high costs, so this solution has never been implemented.

[0039] Based on this, at this stage, electric vehicle charging stations are in urgent need of a low-cost, more convenient and reasonable mobile charging solution. This application provides an electric vehicle mobile fast charging solution based on an 800VDC direct current microgrid.

[0040] See also Figure 1 , which is a schematic diagram of the structure of the mobile fast charging system for electric vehicles based on a DC microgrid according to an embodiment of the present application. Figure 1 As shown, this embodiment provides a mobile fast charging system for electric vehicles based on a DC microgrid, specifically comprising: a DC power supply module 1, a DC cable 2 and a fast charging interface 3 of a mobile charging pile.

[0041] The DC cable 2 is connected to the DC power supply module 1 to transmit the DC voltage output by the DC power supply module 1 .

[0042] The fast charging interface 3 of the mobile charging pile is arranged in the DC cable 2 at preset intervals, so that the mobile charging pile is plugged into the fast charging interface 3 and the electric vehicle is charged using the DC voltage.

[0043] In one embodiment, the DC power supply module includes a transformer rectifier.

[0044] The input end of the transformer-rectifier is connected to three-phase alternating current, and the three-phase alternating current is transformed and rectified to output the direct current voltage.

[0045] See also Figure 2 , which is a schematic diagram of the DC power supply of the mobile fast charging system for electric vehicles based on the DC microgrid described in the embodiment of the present application. Figure 2 As shown, the DC power supply module 1 includes a transformer rectifier. The input end of the transformer rectifier is connected to three-phase AC power, and the DC voltage is output after the three-phase AC power is transformed and rectified. The transformer rectifier includes a transformer unit 11, a rectifier unit 12 and a voltage stabilizing capacitor C1; the rectifier unit 12 is connected to the transformer unit 11 and the voltage stabilizing capacitor C1 respectively.

[0046] The transformer unit 11 converts the input three-phase AC power into a three-phase power supply that meets the charging requirements, and the rectifier unit 12 rectifies the three-phase power supply and outputs it to the voltage stabilizing capacitor C1, and the voltage stabilizing capacitor C1 outputs the DC voltage.

[0047] See also Figure 3 , which shows the DC power supply principle diagram of the mobile fast charging system for electric vehicles based on DC microgrid as described in the embodiment of the present application. Figure 3 As shown, the transformer unit 11 includes a three-phase isolation transformer, and the rectifier unit includes a three-phase rectifier bridge. Specifically, the three-phase electricity a, b, and c output by the three-phase isolation transformer are input to the first three-phase rectifier bridge, the three-phase electricity a', b', and c' are input to the second three-phase rectifier bridge, and the three-phase electricity a", b", and c" are input to the third three-phase rectifier bridge. The positive output ends of the three three-phase rectifier bridges are all connected to the upper end of the voltage-stabilizing capacitor C1, and the negative output ends of the three three-phase rectifier bridges are all connected to the lower end of the voltage-stabilizing capacitor C1. Therefore, the present application uses a transformer rectifier transformer to step down and transform the 10kV voltage into three groups of AC voltages with different amplitudes and phases, and then rectifies them through three groups of rectifier bridges, and connects them in parallel at the output ends of the three groups of rectifier bridges to obtain the DC voltage.

[0048] like Figure 3 As shown, the DC voltage includes 800V DC voltage.

[0049] See also Figure 4, which is a schematic diagram of mobile charging of a mobile fast charging system for electric vehicles based on a DC microgrid according to an embodiment of the present application. Figure 4 As shown, the system also includes: a mobile charging pile.

[0050] The mobile charging pile is provided with a charging plug, and the charging plug is plugged and connected with the fast charging interface. In practical applications, the mobile charging pile is a wheeled movable charging pile.

[0051] like Figure 4 As shown, the three-phase power of 10KV or 380V voltage level is led out through the power transformer to meet the demand of three-phase power supply, and then rectified by a high-power AC / DC rectifier to lead out 800V DC bus to build a DC microgrid as the access power supply for the mobile charging pile. The solution of converting from 10kV to 800V in this application can meet the following requirements at the same time: (1) meet the requirements of the power grid: high power factor, low harmonic content; (2) meet the requirements of users: high efficiency, low cost; (3) meet the requirements of long-term operation: high reliability, long life.

[0052] On the above basis, DC cables are laid along all parking spaces and distributed fast charging interfaces are arranged at specific locations in the parking lot at certain intervals. Each fast charging interface serves as a power interface for a mobile charging pile.

[0053] Since the power supply voltage of this solution is a suspended 800V DC power supply, compared with a 380V AC power supply, the input cable is changed from a three-phase five-wire cable to a two-core cable, and the cross-sectional area is greatly reduced, making the original high cable cost affordable, which is the key to the implementation of this application. Regarding 380V input, to give full play to the advantages of this application, it is best to connect directly from 10kV. However, for occasions where a 10kV / 380V conventional transformer has been installed, in order to avoid repeated investment, it can also be connected from 380V. The technical principle is the same, and the effect achieved is basically the same. The only difference is that there is an additional conversion link, so the operating efficiency is slightly reduced.

[0054] In one embodiment, the mobile charging pile includes a DC conversion module, one end of which is connected to the charging plug, receives the DC voltage, performs DC conversion on the DC voltage, and outputs the charging voltage required for charging the electric vehicle from the other end.

[0055] See also Figure 5 , which is a schematic diagram of the charging pile structure of the mobile fast charging system for electric vehicles based on a DC microgrid as described in the embodiment of the present application. Figure 5As shown, the mobile charging pile includes a DC conversion module (DC-DC conversion module), one end of which is connected to the charging plug. After the charging plug is plugged into the fast charging interface, it receives the 800V DC voltage transmitted by the 800V distribution cable, performs DC conversion on the 800V DC voltage, and outputs the charging voltage required for charging the electric vehicle from the other end. The DC 800V input is converted into a DC 320V output by the DC-DC device inside the mobile charging pile, where the DC-DC device is a DC-to-DC BUCK conversion circuit, where the output power is related to the output power of the DC-DC module, and the output power of DC-DC modules of different powers is different, so mobile charging piles of different power sizes can be configured, such as 20KW, 40KW, and 60KW.

[0056] See also Figure 6 , which is a schematic diagram of charging conversion of a mobile fast charging system for electric vehicles based on a DC microgrid according to an embodiment of the present application. Figure 6 As shown, in an actual application, the electric vehicle, that is, the new energy vehicle, has a rechargeable battery which is a storage battery with a charging voltage of 320VDC. The 800V DC voltage is transmitted to the fast charging interface through an 800V distribution cable. One end of the DC conversion module of the mobile charging pile is connected to the charging plug. After the charging plug is plugged into the fast charging interface, it receives the 800V DC voltage transmitted by the 800V distribution cable, performs DC conversion on the 800V DC voltage, and outputs the charging voltage 320V DC voltage required for charging the new energy vehicle from the other end.

[0057] See also Figure 7 , which is a schematic diagram of the fast charging interface structure of the mobile fast charging system for electric vehicles based on a DC microgrid according to an embodiment of the present application. Figure 7 As shown, the specific form of the fast charging interface that the mobile charging pile charging plug requests to be plugged into is shown.

[0058] In one embodiment, the mobile charging pile includes a plurality of mobile charging piles configured with different power sizes.

[0059] In one embodiment, the mobile charging station includes a retractable cable of a preset length.

[0060] In one embodiment, the DC cable is laid in the parking lot along a preset path, and the preset path is determined according to the distance between different DC cables and the location of the parking spaces. The preset intervals of the fast charging interfaces on the DC cables are determined according to the number of parking spaces planned to be covered by a single fast charging interface.

[0061] See also Figure 8 , which is a schematic diagram of the application structure of the mobile fast charging system for electric vehicles based on a DC microgrid according to an embodiment of the present application. Figure 8As shown, the external AC 10KV is converted to DC 800V by a transformer rectifier, and an 800V DC cable is laid in the parking lot. At the electric vehicle charging station in the parking lot, movable charging piles with different output power are placed, such as 20kw movable charging piles, 30kw movable charging piles and 60kw movable charging piles. The rotating shaft of each charging pile has a 20-meter retractable cable. The laying rules of the DC cable can be laid horizontally according to rows of parking spaces, for example. As a result, the mobile charging pile does not need to occupy a fixed parking space, and there will be no situation where the non-charging vehicle occupies the parking space and blocks the charging pile in the parking space, resulting in low utilization of the charging pile. When a vehicle in a parking space needs to be charged, the mobile charging pile that meets the power is pushed to a nearby position, and the charging plug of the mobile charging pile is plugged into the closer fast charging interface for charging. Thus, after the fast charging connectors are arranged at preset intervals, one fast charging interface can cover the charging tasks of multiple surrounding cars.

[0062] like Figure 8 As shown, the mobile charging pile designed in this application is a DC input charging pile with different power sizes. Figure 5 As shown, the mobile charging pile is a DC input and output charging pile, which contains a DC-DC converter to adjust the output voltage. It is movable with universal wheels on the outside, and a cable with a plug is wrapped around the pile body.

[0063] When a vehicle that needs to be charged randomly enters a parking space, the owner scans the code to send a charging instruction. After receiving the instruction, the staff can move the charging pile to the parking space, connect the plug of the charging pile to the quick connector, and then connect the charging gun to the vehicle that needs to be charged to complete the charging. After charging is completed, the staff will remove the charging pile and continue charging other vehicles that need to be charged.

[0064] The use of mobile charging can solve the problem of low charging pile utilization caused by fixed charging spaces in large shopping mall parking lots being occupied by gasoline vehicles or fully charged electric vehicles.

[0065] Based on the structure and connection relationship of the mobile fast charging system for electric vehicles of this application, a specific application implementation case of this application is as follows: In a large parking lot based on a DC charging station system with a system voltage of 800V, the rectifier transformer uniformly rectifies and leads to an 800V DC bus, and DC cables are laid along the parking lot, and quick connectors are installed every 30 meters as the power interface of the mobile charging pile. Then a movable DC input charging pile of different power sizes is designed, and the pile body is equipped with a cable with a plug and two charging guns. When the vehicle enters the parking lot, you can choose a parking space to park the electric car at will, and then enter the parking space number and charging requirements and other information through the APP (short for Application) or applet. The cloud platform will respond to the charging information to the dedicated charging station staff. After receiving the information, the staff will move the mobile charging pile to the designated parking space. Then the staff will find a quick interface near the parking space to connect the mobile charging pile to the power supply, and then insert the charging gun into the vehicle to be charged, and enter the corresponding charging information to charge. After charging is completed, the staff will move the charging pile back or to other vehicles that need to be charged.

[0066] Therefore, the fast charging solution based on 800V DC microgrid power supply has greatly reduced the use of cables, making the mobile charging solution feasible, which was impossible to implement due to high cost under 380V AC power supply.

[0067] Compared with traditional fixed charging piles, mobile charging solutions can effectively solve the problem of gasoline vehicles occupying charging parking spaces and electric vehicles occupying charging parking spaces when fully charged. There is no need to set up special charging parking spaces separately, which improves the utilization rate of parking spaces and charging piles and the operating efficiency of charging stations, and reduces the investment in charging equipment. Secondly, it solves many pain points of fixed charging pile charging scenarios. There is no need to queue for charging, and charging can basically be achieved as soon as the car stops, so users can get a senseless charging experience. For electric vehicles that require large-capacity charging, DC power supply can complete the charging process faster and meet users' needs for fast charging.

[0068] In the several embodiments provided in the present application, it should be understood that the disclosed system can be implemented in other ways. For example, the system embodiments described above are only schematic, for example, the division of modules / units is only a logical function division, and there may be other division methods in actual implementation, such as multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules or units, which can be electrical, mechanical or other forms.

[0069] The modules / units described as separate components may or may not be physically separated, and the components displayed as modules / units may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules / units may be selected according to actual needs to achieve the purpose of the embodiments of the present application. For example, the functional modules / units in the various embodiments of the present application may be integrated into one processing module, or each module / unit may exist physically separately, or two or more modules / units may be integrated into one module / unit.

[0070] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A mobile fast charging system for electric vehicles based on a DC microgrid, characterized in that: The system comprises: DC power supply module; A DC cable, connected to the DC power supply module, for transmitting the DC voltage output by the DC power supply module; The fast charging interface of the mobile charging pile is arranged in the DC cable at preset intervals, so that the mobile charging pile is plugged into the fast charging interface and the electric vehicle is charged using the DC voltage.

2. The system according to claim 1, characterized in that The DC power supply module includes a transformer rectifier; The input end of the transformer-rectifier is connected to three-phase alternating current, and the three-phase alternating current is transformed and rectified to output the direct current voltage.

3. The system according to claim 2, characterized in that The transformer rectifier comprises a transformer unit, a rectifier unit and a voltage stabilizing capacitor; the rectifier unit is connected to the transformer unit and the voltage stabilizing capacitor respectively; The transformer unit converts the input three-phase alternating current into a three-phase power supply that meets the charging requirements, the rectifier unit rectifies the three-phase power supply and outputs it to the voltage stabilizing capacitor, and the voltage stabilizing capacitor outputs the DC voltage.

4. The system according to claim 3, characterized in that: The transformer unit includes a three-phase isolation transformer, and the rectifier unit includes a three-phase rectifier bridge.

5. The system according to claim 1, characterized in that: The DC voltage includes 800V DC voltage.

6. The system according to claim 1, characterized in that The system also includes: a mobile charging pile; The mobile charging pile is provided with a charging plug, and the charging plug is plugged and connected with the fast charging interface.

7. The system according to claim 6, characterized in that: The mobile charging pile includes a DC conversion module, one end of which is connected to the charging plug, receives the DC voltage, performs DC conversion on the DC voltage, and outputs the charging voltage required for charging the electric vehicle from the other end.

8. The system according to claim 7, characterized in that: The mobile charging pile includes a plurality of mobile charging piles configured with different power sizes.

9. The system according to claim 6, characterized in that: The mobile charging station includes a retractable cable of a preset length.

10. The system according to claim 1, characterized in that: The DC cables are laid in the parking lot along a preset path, and the preset path is determined according to the distance between different DC cables and the location of the parking spaces. The preset intervals of the fast charging interfaces on the DC cables are determined according to the number of parking spaces planned to be covered by a single fast charging interface.

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