Converter devices for connecting electric vehicles to the power grid, battery storage, and other power sources in charging systems.
By introducing rectifiers, DC-DC voltage converters, and current isolation components into the charging system, and combining multiple switch groups, efficient connection between multiple energy sources is achieved, solving the problems of high loss and high cost in existing technologies, and improving charging efficiency and system benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- VOLKSWAGEN AG
- Filing Date
- 2019-05-07
- Publication Date
- 2026-05-26
AI Technical Summary
Existing charging systems suffer from high losses and high costs when connecting to DC power sources and AC power grids, especially when switching between multiple energy sources, resulting in low efficiency.
A charging system was designed, comprising a rectifier, a first DC-DC voltage converter, a current isolation element, and multiple switch groups. It achieves efficient connection of various energy sources and sinks through intelligent wiring, reducing hardware usage and optimizing voltage level adjustment.
It improves overall efficiency, such as achieving high efficiency of 96% or 98% when charging electric vehicles from solar power, and reduces hardware requirements and system costs.
Smart Images
Figure CN112106285B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a charging system. Background Technology
[0002] The energy supply in future homes will be far more complex than it is today, as the transition to renewable energy and electric vehicles places different demands on energy supply. In addition to standard AC grid connections, future energy sources will include DC power sources such as photovoltaic systems or home storage devices (Heimspeichers). Furthermore, electric vehicles will become major energy consumers not currently integrated into the grid infrastructure for home electrical appliances.
[0003] When a DC power source or energy sink is connected to a home's AC grid, a bidirectional rectifier / inverter is typically required, along with an additional boost / buck converter. This results in significant losses and high costs due to the installed power electronics, leading to repeated conversions. Typically, each source—whether a photovoltaic system, a home storage device, or a vehicle—connects to the existing AC grid using its own power electronics. For example, solar current from a photovoltaic system can be temporarily stored in a DC-HV home storage device via a boost / buck converter (e.g., 98% efficiency), a photovoltaic inverter (e.g., 97% efficiency), a bidirectional rectifier (e.g., 97% efficiency), and a boost / buck converter (e.g., 98% efficiency). Then, if the vehicle is charged overnight, the solar current from the DC-HV home storage device is transmitted to the home's AC grid via a bidirectional rectifier (e.g., 97% efficiency) and a boost / buck converter (e.g., 98% efficiency). A DC high-voltage battery is charged from the house's AC grid using a rectifier with a boost / buck converter and current isolation (efficiency, for example, 97%). The result is, for example, an overall efficiency of 79%. This efficiency is clearly too low for residential applications.
[0004] A charging device, particularly for a motor vehicle having at least two power input terminals, is known from DE 10 2011 083 020 A1. The power input terminals can be coupled to different power sources respectively. Furthermore, there is a power output terminal that can be coupled to a battery, particularly a vehicle high-voltage battery. Additionally, there is a controllable switching device configured to connect and / or disconnect the electrical connection between at least one of the power input terminals and the power output terminal. Therefore, the charging device has a controllable switching device by which different energy sources can be connected to the battery, thereby reliably providing a DC voltage for charging the battery. Since multiple components can be used multiple times, the charging device can be constructed more simply and at a lower cost. Here, a single rectifier can be used for multiple AC voltage sources. For all power input terminals, a single converter electronics is present. This converter electronics is arranged between the power input terminals and the switching device. The converter electronics has a controllable rectifier and a controllable voltage converter. Thus, different DC and AC voltages can be converted to the DC voltage required for battery charging. This makes it possible to integrate different charging systems into a single charging device. In one embodiment, the converter electronics are not arranged in the power input terminals but are associated with the power output terminals. Therefore, the vehicle can have a high-voltage battery coupled to a corresponding charging device. The charging device is part of the motor vehicle. The charging device provides three power input terminals, each coupled to a corresponding switching device via two separate electrical lines. Here, the switching device has a switch for each power input terminal. On the output side, the switching device is coupled to the power output terminal. Two of the power input terminals are connected to the converter electronics in the form of rectifiers. Another power input terminal is coupled to a DC voltage high-energy source. The other two power input terminals can be coupled to a household current source or a wireless power source. A converter electronics with a single combination is disclosed, having a controllable rectifier and a voltage converter. The voltage converter electronics can have a buck-boost-wanler converter, i.e., a DC voltage converter not isolated from the memory choke current.
[0005] A method for using a converter for both conductive and inductive charging of an electric vehicle is known from DE 10 2013 220 704 A1. The corresponding circuit includes a DC-DC voltage converter, a current converter circuit, and a switching device. The DC-DC voltage converter is formed by a buck converter. The DC-DC voltage converter may have current isolation between its DC voltage input and DC voltage output. The current converter circuit is connected to a DC voltage connector, wherein the switching device is configured to switchably couple the current converter circuit to either a conductive connector or an inductive connector.
[0006] It is known from JP H-07250405 A that two batteries are charged by means of a charging system, wherein the charging system has an inverter and a timing switch. Summary of the Invention
[0007] Therefore, the technical problem to be solved by the present invention is to design a charging system that can distribute energy or current in a highly efficient and optimized manner.
[0008] The aforementioned technical problem is solved by a charging system according to the present invention. This charging system has at least one DC voltage connector (hereinafter also referred to as a DC power connector) and at least one AC voltage connector (hereinafter also referred to as an AC power connector) and a battery power connector, wherein the battery power connector can be connected to a battery, particularly a vehicle high-voltage battery. The charging system has a rectifier, wherein the rectifier is connected to the AC power connector. Furthermore, the charging system has a first DC voltage converter. The rectifier is connected to the AC power connector on one side and to the first DC voltage converter on the other. The first DC voltage converter is connected to the DC voltage side of the rectifier. The first DC voltage converter is particularly configured as a boost / buck converter. Furthermore, the charging system has a current isolation element, particularly a current isolation element in the form of a second DC voltage converter. The first DC voltage converter is connected to the rectifier on one side and to the current isolation element on the other. The current isolation element is connected to the first DC voltage converter on one side and to the battery power connector on the other. At least one DC power connector is connected or can be connected to the rectifier and the first DC voltage converter via a first switch group, and is connected or can be connected to the first DC voltage converter and the current isolation element via a second switch group. This design of the charging system provides a charging system with multiple connectors or interfaces. This charging system can charge from any connector to another. The rectifier, the first DC-DC voltage converter, and the current isolation element operate bidirectionally. Here, the key feature is a common DC voltage reference network and the use of only one boost / buck converter, which, through intelligent wiring, can form a fully variable source-sink connection via appropriate connectors.
[0009] Therefore, inverters and boost / buck converters can be eliminated at each DC source, such as at photovoltaic devices or home storage devices. This charging system enables intelligent connection between energy sinks and sources, requiring only the minimum possible hardware. Due to the reduced hardware, the overall system efficiency and effectiveness are improved. The necessary switches or switch groups connect each source to each sink. This results in increased efficiency, for example, when charging an electric vehicle from a home storage device already charged with solar current.
[0010] Correspondingly, the input and output terminals of the current isolation element can be bypassed using corresponding additional switches. This further improves efficiency. The power path mentioned above is shortened to photovoltaic equipment, boost / buck converter, DC high-voltage memory, and boost / buck converter and vehicle, where the current isolation element is bypassed. This produces, for example, a total efficiency of 96% without considering losses in the household memory. Furthermore, the efficiency of charging the vehicle from a DC voltage source such as photovoltaic equipment, household memory, or fuel cell can be further improved by using two sets of switches, especially following the low-voltage grid requirements of the standard, the so-called IT grid (Isolé Terre-Netz), and thus the current isolation can be bypassed because the household memory and photovoltaic equipment already have grounding. Thus, for example, when charging an electric vehicle directly from a solar power source, i.e., photovoltaic equipment, improved efficiency is obtained, with the power path shortened to photovoltaic equipment, buck converter, and vehicle. This results in a total efficiency of 98%. The voltage levels between the various sources and sinks can be adjusted by the boost / buck converter. This allows for a more compact and advantageous charging system than current technologies. Attached Figure Description
[0011] Currently, there are several possibilities for designing and expanding the charging system. The preferred design of the invention will now be described in more detail with reference to the accompanying drawings and associated description. In the drawings:
[0012] Figure 1 A charging system according to the invention, along with multiple sources and energy sinks, is shown in a very schematic view. Detailed Implementation
[0013] Figure 1 A charging system 1 is shown, having at least one, and particularly multiple, DC current connectors, hereinafter referred to as DC power connectors 2 and 3. For example, a household storage device 4 can be connected to DC power connector 2, and a photovoltaic device 5 can be connected to DC power connector 3. Furthermore, the charging system 1 has a battery power connector 6, which is connected to or can be connected to a battery 7, particularly a vehicle high-voltage battery 7. Additionally, the charging system 1 has an AC voltage connector, hereinafter referred to as AC power connector 8. AC power connector 8 is connected to an AC power grid 9. The AC power grid 9 can be formed, for example, by a 220-volt or 110-volt AC power grid with a frequency of 50 Hz.
[0014] The charging system 1 includes a rectifier 10, which is connected to the AC power grid 9 (i.e., to the AC power connector 8) and to a first DC-DC voltage converter 11 on the DC voltage side. The first DC-DC voltage converter 11 is specifically configured as a boost / buck converter. The first DC-DC voltage converter 11 is connected to the DC side of the rectifier 10. The first DC-DC voltage converter 11 is then connected to a current isolation element 12 on the other side. The current isolation element 12 can be formed from a second DC-DC voltage converter. The current isolation element 12 is connected to the first DC-DC voltage converter 11 on one side and to the AC power connector 8 on the other. The current isolation element 12 provides current isolation. Here, the current isolation element 12 can be bypassed using switches S2a and S2b.
[0015] At this point, the charging system 1 has a first switch group S1a and a second switch group S1b. Switch groups S1a and S1b each have multiple switches that can operate independently of each other, and these switches are associated with the connected source, DC power connectors 2 and 3, respectively. Now, at least one DC power connector 2 or 3 is connected or can be connected to the rectifier 10 and the first DC voltage converter 11 via the first switch group S1a. Furthermore, at least one DC power connector 2 or 3 can be connected to the first DC voltage converter 11 and the current isolation element 12 or the second DC voltage converter via the second switch group S1b. Now, the charging system 1 has multiple interfaces in the form of DC power connectors 2 and 3, AC power connector 8, and battery power connector 6. The charging system 1 can be charged from any connector to another. A common DC voltage reference network is used. Furthermore, using only a single boost / buck converter in the form of the first DC voltage converter 11, which can be intelligently wired to form a completely different connection with a source and sink (Senke). Thus, the inverter and boost / buck converter can be omitted at each DC source, such as the household storage device 4 or the photovoltaic device 5. This charging system 1 enables intelligent wiring of the different electrical sources mentioned above, requiring only the minimum possible hardware. Due to the reduced hardware components, the overall system efficiency and effectiveness are improved. The necessary switch modules S1a and S1b can be universally connected to each source and sink.
[0016] Now, power flow from the AC grid 9 to the vehicle, i.e., to the battery 7, is achieved via rectifier 10, boost / buck converter 11, and second DC voltage converter 12. Power flow between the photovoltaic device 5 and the AC grid 9 is achieved by keeping the first switch group S1a in the open position and closing the corresponding switches in the second switch group S1b, thereby providing a connection between the photovoltaic device 5, the boost / buck converter 11 and rectifier 10, and all the way to the AC power connector 8, i.e., the AC grid 9.
[0017] By keeping switch group S1a in the open position and closing the corresponding switches in switch group S1b, a power flow between AC grid 9 and household storage 4 is provided via rectifier 10, boost / buck converter 11, and household storage 4. By closing the corresponding switches in the first switch group S1 and opening the second switch group S1b, a power flow between household storage 4 and the vehicle, i.e., battery 7, is provided via boost / buck converter 11 to vehicle battery 7, where switches S2a and S2b are closed to bypass current isolation element 12. By opening the first switch group S1a and closing the corresponding switches in the second switch group S1b, photovoltaic device 5 is directly connected to the vehicle, generating a power flow between photovoltaic device 5 and the vehicle in the form of battery 7. Both household storage 4 and photovoltaic device 5 have ground, allowing current isolation element 12 to be bypassed when charging vehicle battery 7 from household storage 4 or photovoltaic device 5. This further improves efficiency.
[0018] Power flow can be provided between photovoltaic device 5 and home memory 4 by closing the switches associated with photovoltaic device 5 and home memory 4 in switch group S1a and switch group S1b.
[0019] The charging system 1 forms a smart charging station that can connect photovoltaic equipment 5 and home storage device 4 in an efficiency-optimized manner. Other interfaces can be, for example, fuel cells, wind turbines, electrolyzers, etc. This charging system can also be used in many applications, such as electric vehicles, shipping, aerospace, home applications, or industrial applications.
[0020] List of reference numerals
[0021] 1 Charging System
[0022] 2 DC power connectors
[0023] 3 DC power connectors
[0024] 4 Home Storage
[0025] 5 Photovoltaic Equipment
[0026] 6 Battery Power Connector
[0027] 7. Battery / Vehicle High Voltage Battery
[0028] 8 AC power connectors
[0029] 9 AC power grid
[0030] 10 rectifiers
[0031] 11 First DC-DC voltage converter / boost / buck converter
[0032] 12 Current Isolation Elements
[0033] S1a First Switch Group
[0034] S1b Second Switch Group
[0035] S2a Third Switch
[0036] S2b fourth switch
Claims
1. A charging system (1) having at least one DC power connector (2, 3) and at least one AC power connector (8) and a battery power connector (6), wherein, The battery power connector (6) can be connected to the battery (7), wherein at least one AC power connector (8) is connected to the rectifier (10), wherein a first DC voltage converter (11) is present, wherein the first DC voltage converter (11) is connected to the DC side of the rectifier (10), wherein the first DC voltage converter (11) is configured as a boost / buck converter, wherein a current isolation element (12) can be connected to the first DC voltage converter (11) and the battery power connector (6), wherein at least one DC power connector (2, 3) can be connected to the rectifier (10) and the first DC voltage converter (11) via a first switch group (S1a), and can be connected to the first DC voltage converter (11) and the current isolation element (12) via a second switch group (S1b), wherein one DC power connector (3) is connected to the home storage device (4), wherein one DC power connector (2) is connected to the photovoltaic device (5). The rectifier (10), the first DC-DC voltage converter (11), and the current isolation element (12) operate bidirectionally, thereby enabling charging from one connector to another via the charging system. The system is characterized by the ability to bypass the input and output terminals of the current isolation element (12) via corresponding additional switches (S2a, S2b), wherein the current isolation element (12) is formed by a second DC-DC voltage converter, and two DC power connectors (2, 3) are directly connected to the first DC-DC voltage converter (11) via the switch group (S1a, S1b). Power flow is provided between the photovoltaic device (5) and the home storage device (4) by closing the switches associated with the photovoltaic device (5) and the home storage device (4) via the first DC-DC voltage converter (11).
2. The charging system according to claim 1, characterized in that, A DC power connector is connected to the fuel cell.
3. The charging system according to claim 1, characterized in that, The battery (7) is a vehicle high-voltage battery.