CN112106285A - High-efficiency converter arrangement for charging systems for electric vehicles for connecting an electrical network, a battery store and other sources - Google Patents

Abstract

The invention relates to a charging system (1) having at least one DC power connection (2, 3) and at least one AC power connection (8) and a battery power connection (6), wherein the battery power connection (6) can be connected with A battery ( 7 ), in particular a high-voltage vehicle battery ( 7 ), is connected, wherein at least one AC power connection ( 8 ) is connected to a rectifier ( 10 ), wherein a first DC voltage converter ( 11 ) is present. Electrical energy or current can be distributed in an efficient and efficiency-optimized manner by connecting the first DC voltage converter ( 11 ) to the DC side of the rectifier ( 10 ), wherein the first DC voltage converter ( 11 ) is designed as a boost/buck converter, wherein the galvanic isolation element (12) can be connected to the first DC voltage converter (11) and the battery power connection (6), wherein at least one DC power connection (2, 3) ) can be connected to the rectifier (10) and to the first DC voltage converter (11) via the first switch group (S1a), and to the first DC voltage converter (11) and to the first DC voltage converter (11) via the second switch group (S1b). A galvanic isolation element (12) is connected.

Description

Charging for electric vehicles for connection to grid, battery storage and other sources High-efficiency converter device for the system

technical field

The invention relates to a charging system having the features of the preamble of claim 1 .

Background technique

Since the transition to renewable energy and electric vehicles places different demands on the energy supply, the energy supply in the house of the future will be much more complex than it is today. In addition to the standard AC grid connection, other DC power sources will also be added in the future, for example photovoltaics or household storage (Heimspeicher). In addition, electric vehicles will become large energy consuming devices that are not provided in the current grid infrastructure of household electrical devices.

When the DC source or energy sink (Senke) is connected to the AC grid of the house, a bidirectional rectifier/inverter is usually required, and an additional boost/buck converter is required. This results in large losses and high costs for repeated conversions due to the installed power electronics. Typically, each source, either a photovoltaic device, or a home storage device, or a vehicle, is connected to the existing AC grid with its own power electronics. For example, solar current from a photovoltaic device can be routed through a boost/buck converter (eg, 98% efficiency) and the photovoltaic device's inverter (eg, 97% efficiency) and bidirectional rectifier (eg, 97% efficiency), boosting The buck/buck converter (efficiency, for example, 98%) is temporarily stored in a DC high voltage storage (DC-HV household storage). At this time, if the vehicle is charged at night, the solar current from the DC-HV home storage is transferred via a bidirectional rectifier (e.g. 97% efficiency) to the house's AC via a boost/buck converter (e.g. 98% efficiency) in the grid. The DC high voltage battery is charged from the AC grid of the house by means of a rectifier with boost/buck converter and galvanic isolation (efficiency eg 97%). As a result, an overall efficiency of, for example, 79% is achieved. For home applications, this efficiency is obviously too low.

A charging device is known from DE 10 2011 083 020 A1, in particular for motor vehicles having at least two power input connections. The power input connectors can be respectively coupled to different power sources. Furthermore, there are power output connections that can be coupled to a battery, in particular a vehicle high voltage battery. Furthermore, there are controllable switching devices which are configured for making and/or breaking the electrical connection between at least one of the power input connections and the power output connections. Therefore, the charging device has a controllable switching device with which different energy sources can be connected to the battery, so that the DC voltage for charging the battery can be reliably provided. Since multiple parts can be used multiple times, it is simpler and cheaper to build charging devices. Here, for multiple AC voltage sources, a single rectifier can be used. There is a single converter electronics for all power input connections. Such converter electronics are arranged between the power input connection and the switching device. The converter electronics have a controllable rectifier and a controllable voltage converter. As a result, DC voltages and AC voltages of different magnitudes can be converted into DC voltages required to charge the battery. This enables the integration of different charging systems into a single charging unit. In one embodiment, the converter electronics are not arranged in the power input connection, but are associated with the power output connection. Thus, the vehicle may have a vehicle 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 connections, which are each coupled to the respective switchgear via two own electrical lines. In this case, the switching devices each have a switch for each power input connection. On the output side, the switching device is coupled to the power output connection. Two of the power input connections are each connected to converter electronics in the form of rectifiers. The other power input connector is coupled to a large energy source of DC voltage. The other two power input connectors can be coupled with a household electrical current source or with a wireless energy source. Disclosed is converter electronics provided with a single combination with a controllable rectifier and voltage converter. The voltage converter electronics may have a buck-boost converter (Buck-Boost-Wandler), ie a DC voltage converter that is not galvanically isolated from the memory choke.

From DE 10 2013 220 704 A1 a dual use of a converter for conductive and inductive charging of electric vehicles is known. The corresponding circuit has a DC voltage converter, a current converter circuit and a changeover switch. The DC voltage converter is formed by a buck converter. The DC voltage converter may have galvanic isolation between the DC voltage input and the DC voltage output. The current converter circuit is connected to the DC voltage connection, wherein the changeover switch is designed to switchably couple the current converter circuit to the conductive connection or the inductive connection.

It is known from JP H-07250405 A to charge two batteries by means of a charging system, wherein the charging system has a converter and a timer switch.

SUMMARY OF THE INVENTION

Therefore, the technical problem to be solved by the present invention is to design the charging system so that energy or current can be distributed in an efficient and efficiency-optimized manner.

The above technical problem is solved by a charging system having the features of claim 1 . The charging system has at least one DC voltage connection (also referred to below as DC power connection) and at least one AC voltage connection (also referred to below as AC power connection) and a battery power connection, wherein the battery power connection can be connected to the battery , especially the vehicle high-voltage battery connection. The charging system has a rectifier, wherein the rectifier is connected to the AC power connection. Furthermore, the charging system has a first DC voltage converter. The rectifier is connected to the AC power connection on the one hand and to the first DC voltage converter on the other hand. The first DC voltage converter is connected to the DC voltage side of the rectifier. The first DC voltage converter is designed in particular as a boost/buck converter. Furthermore, the charging system has a galvanic isolation element, in particular in the form of a second DC voltage converter. The first DC voltage converter is connected to the rectifier on the one hand and to the galvanic isolation element on the other hand. The galvanic isolation element is connected to the first DC voltage converter on the one hand and to the battery power connection on the other hand. At least one DC power connection is connected or connectable to the rectifier and the first DC voltage converter via the first switch group and to the first DC voltage converter and the galvanic isolation element via the second switch group. With this design of the charging system, a charging system with multiple connectors or interfaces is provided. This charging system can charge from either connector to the other. The rectifier, the first DC voltage converter and the galvanic isolation element operate bidirectionally. Here, the features are a common DC voltage reference network and the use of only one boost/buck converter, which, through intelligent wiring, can form a fully variable connection of source and sink via corresponding connections.

Thereby, inverters and boost/buck converters can be dispensed with at each DC source, eg at photovoltaic installations or household storage. Such a charging system enables an intelligent connection of energy sinks to sources so that only the minimum possible hardware usage has to be achieved. As the hardware part is reduced, the efficiency and effectiveness of the whole system are improved. The switches or switch groups required for this can connect each source with each sink. As a result, increased efficiency is obtained, for example, when charging an electric vehicle from a domestic storage device that has already been charged by means of solar current.

Accordingly, the input and output of the galvanic isolation element can be bypassed by means of corresponding further switches. As a result, the efficiency can be further improved. The power paths mentioned above are shortened to photovoltaic devices, boost/buck converters, DC high voltage storage and boost/buck converters and vehicles, where galvanic isolation elements are bypassed. This yields, for example, an overall efficiency of 96%, without taking into account losses in the home memory. In addition, by means of two switch banks, the efficiency of charging the vehicle from a DC voltage source such as photovoltaics, household storage or fuel cells can be further increased, since here, in particular, the standard-compliant low-voltage grid, the so-called IT grid (Isolé Terre-Netz), and thus galvanic isolation can be bypassed, since household storage and photovoltaics already have ground. Thereby, for example when charging an electric vehicle directly from a solar power source, ie a photovoltaic device, an increased efficiency is obtained, the power path is shortened to the photovoltaic device, the buck converter and the vehicle. This gives an overall efficiency of 98%. The voltage level between each source and sink can be adjusted by a boost/buck converter. This may enable a more compact and more advantageous charging system than the current state of the art.

Description of drawings

Now, there are multiple possibilities to design and expand charging systems. Reference is first made to the claims subordinate to claim 1 . In the following, preferred designs of the present invention are described in more detail with reference to the accompanying drawings and the associated description. In the attached picture:

FIG. 1 shows a charging system according to the invention and a plurality of sources and energy sinks in a very schematic view.

Detailed ways

FIG. 1 shows a charging system 1 having at least one, in particular a plurality of direct current connections, which will be referred to below as direct current connections 2 , 3 . For example a domestic storage 4 can be connected to the DC power connection 2 and, for example, a photovoltaic device 5 can be connected to the DC power connection 3 . Furthermore, the charging system 1 has a battery power connection 6 , wherein the battery power connection 6 is or can be connected to a battery 7 , in particular a high-voltage vehicle battery 7 . Furthermore, the charging system 1 has an AC voltage connection, which is referred to below as an AC power connection 8 . The AC power connection 8 is connected to the AC grid 9 . The alternating current network 9 can be formed, for example, by an alternating current network of 220 volts or 110 volts and a frequency of 50 Hz.

The charging system 1 has a rectifier 10 , wherein the rectifier 10 is connected on the one hand to the AC network 9 , ie, to the AC power connection 8 , and on the DC voltage side to the first DC voltage converter 11 . The first DC voltage converter 11 is designed in particular as a boost/buck converter. The first DC voltage converter 11 is connected to the DC side of the rectifier 10 . The first DC voltage converter 11 is now connected on the other side to the galvanic isolation element 12 . The galvanic isolation element 12 may be formed by a second DC voltage converter. The galvanic isolation element 12 is connected on the one hand to the first DC voltage converter 11 and on the other hand to the AC power connection 8 . The galvanic isolation element 12 can achieve galvanic isolation. Here, the galvanic isolation element 12 can be bypassed via switches S2a and S2b.

At this time, the charging system 1 has a first switch group S1a and a second switch group S1b. The switch banks S1a and S1b each have a plurality of switches operable independently of each other, which switches are associated with the connected source, DC power connections 2, 3, respectively. At least one DC power connection 2 , 3 is now connected or connectable to the rectifier 10 and the first DC voltage converter 11 via the first switch group S1a. Furthermore, at least one DC power connection 2 , 3 can be connected via the second switch group S1 b to the first DC voltage converter 11 and the galvanic isolation element 12 or the second DC voltage converter. The charging system 1 now has a plurality of interfaces in the form of DC power connections 2 , 3 , AC power connections 8 and battery power connections 6 . The charging system 1 can be charged from any connector to another connector. Use a common DC voltage reference network. Furthermore, only a single boost/buck converter in the form of the first DC voltage converter 11 is used, which can be wired intelligently to form a complete variation of the connection with source and sink (Senke). As a result, a converter and a boost/buck converter can be dispensed with at each DC source, for example the domestic storage 4 or the photovoltaic device 5 . With this charging system 1 it is possible to realize the above-mentioned intelligent wiring of the sinks of the different electrical sources, so that only the lowest possible hardware usage has to be achieved. As the hardware part is reduced, the efficiency and effectiveness of the whole system are improved. The switching modules S1a and S1b required for this can be universally connected to each source and sink.

Now, via the rectifier 10 , the boost/buck converter 11 and the second DC voltage converter 12 , a power flow from the AC grid 9 to the vehicle, ie to the battery 7 is achieved. By keeping the first switch bank S1a in the open position and closing the corresponding switches in the second switch bank S1b, the photovoltaic device 5, the boost/buck converter 11 and the rectifier 10 are provided, up to the AC power connection 8. The connection between the AC power grid 9 to realize the power flow between the photovoltaic device 5 and the AC power grid 9 .

The AC grid is achieved by keeping the switch bank S1a in the open position and closing the corresponding switches in the switch bank S1b, thereby providing a connection of the AC grid via the rectifier 10 , the boost/buck converter 11 and the household storage 4 . Power flow between 9 and home storage 4. The home memory 4 is provided with a The power flow between the motor vehicles, ie the battery 7 , wherein the switches S2a, S2b are closed in order to bypass the galvanic isolation element 12 . By opening the first switch group S1a and closing the corresponding switches in the second switch group S1b so that the photovoltaic device 5 is directly connected to the vehicle, a power flow is generated between the photovoltaic device 5 and the vehicle in the form of a battery 7 . The household storage device 4 and the photovoltaic device 5 each have a ground, so that the galvanic isolation element 12 can be bypassed when the vehicle battery 7 is charged from the domestic storage device 4 or the photovoltaic device 5 . This further increases the efficiency.

The photovoltaic device 5 can be connected to the domestic storage 4 via the boost/buck converter 11 by closing the switches associated with the photovoltaic device 5 and the domestic storage 4 in switch banks S1a and S1b, where the photovoltaic device 5 is connected to the domestic storage 4. Power flow is provided between the household memories 4 .

The charging system 1 forms an intelligent charging station, which can connect the photovoltaic installation 5 and the domestic storage 4 in an efficiency-optimized manner. Other interfaces may be, for example, fuel cells, wind turbines, electrolyzers, and the like. Such charging systems can also be used in many applications, such as in electric vehicles, shipping, aerospace, domestic applications or industrial applications.

List of reference signs

1 Charging system

2 DC power connector

3 DC power connector

4 Home Storage

5 Photovoltaic equipment

6 Battery Power Connector

7 Batteries/Vehicle High Voltage Batteries

8 AC power connector

9 AC grid

10 Rectifier

11 First DC voltage converter/boost/buck converter

12 Galvanic isolation element

S1a first switch group

S1b second switch group

S2a third switch

S2b Fourth switch

Claims (6)

1. Charging system (1) having at least one direct current power connection (2, 3) and at least one alternating current power connection (8) and a battery power connection (6), wherein the battery power connection (6) can be connected to a battery (7), in particular a vehicle high-voltage battery (7), wherein the at least one alternating current power connection (8) is connected to a rectifier (10), wherein a first direct current voltage converter (11) is present, characterized in that the first direct current voltage converter (11) is connected to the direct current side of the rectifier (10), wherein the first direct current voltage converter (11) is designed as a step-up/step-down converter, wherein a galvanic isolation element (12) can be connected to the first direct current voltage converter (11) and the battery power connection (6), wherein the at least one direct current power connection (2, 3) can be connected to the rectifier (10) and to the first direct-current voltage converter (11) via a first switch group (S1a), and can be connected to the first direct-current voltage converter (11) and to the galvanic isolation element (12) via a second switch group (S1 b).

2. Charging system according to claim 1, characterized in that one direct current power connection (2) is connected to a photovoltaic device (5).

3. Charging system according to any of the preceding claims, characterized in that a direct current power connection (3) is connected to the domestic storage (4).

4. A charging system according to any of the preceding claims, wherein a dc power connection is connected to the fuel cell.

5. Charging system according to any of the preceding claims, characterized in that the rectifier (10), the first direct voltage converter (11) and the galvanic isolation element (12) work bidirectionally, so that charging from any connection to another connection is possible by means of the charging system.

6. Charging system according to one of the preceding claims, characterized in that the input and output of the galvanic isolation element (12) can be bypassed by means of a respective further switch (S2a, S2b), respectively.

Images