Energy system for electric vehicles

Abstract

The invention relates to an energy system for an electric vehicle. The electric vehicle has at least one high-voltage on-board network and at least one low-voltage on-board network, wherein the system comprises a high-voltage battery, which is connected to the at least one high-voltage on-board network via an interrupting element, wherein the high-voltage battery comprises a first branch and a second branch connected in series, wherein a first input module of a DC / DC converter is connected to the first branch, the first input module comprising a high-voltage bridge and being connected to a first primary winding of a transformer having two primary windings and a common secondary winding, a second input module of the DC / DC converter is connected to the second branch, the second input module comprising a high-voltage bridge and being connected to a second primary winding of the transformer having two primary windings and a common secondary winding, and an output of the DC / DC converter is connected to the at least one low-voltage on-board network. Furthermore, the invention also relates to a method for supplying an electric vehicle with electrical energy.

Description

Technical Field

[0001] The present invention relates to a system for supplying electrical energy to a vehicle and a method for supplying electrical energy to a vehicle. Background Technology

[0002] In today's electrically driven vehicles, such as plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), or hybrid electric vehicles (HEVs) equipped with high-voltage energy storage (high-voltage batteries), direct current converters (DC / DC converters) are used to power the low-voltage on-board network (low-voltage on-board network). The DC / DC converter is primarily powered by the high-voltage battery and is connected to the overall system voltage after the battery contactor. Currently, these high-voltage networks are not subject to any ASIL safety classification and are therefore only conditionally applicable, or, depending on type, completely unsuitable, for applications with highly automated driver assistance systems.

[0003] KR 101 548 528 B1 relates to a DC / DC converter. The DC / DC converter includes: a switching unit that alternately switches DC input power; a transformer unit that includes a single transformer having a primary winding and a secondary winding, converts power input to the primary winding, and outputs the converted power to the secondary winding side; a rectifier unit that includes switching elements and first to fourth diodes, and operates in a high-voltage mode or a low-voltage mode depending on the operation of the switching elements; and an output filter that filters the power output from the rectifier unit.

[0004] JP 2008 / 005685 A describes a DC-DC converter with a circuit structure in which a single-winding transformer, forming a common portion of the winding between the primary and secondary windings, is used to apply voltage (which is distributed according to the winding ratio) to a synchronous rectifier switch when the main switch is on, in order to prevent the input voltage from being directly applied to the synchronous rectifier switch. Thus, components with a breakdown voltage lower than the input voltage can be used in the synchronous rectifier switch, thereby reducing conduction losses and improving the efficiency of the DC-DC converter. Summary of the Invention

[0005] Therefore, the object of this invention is to reliably supply electrical energy to the low-voltage on-board network of electric vehicles, and the electrical energy also meets the safety standards for highly automated driving assistance systems.

[0006] This objective is achieved through systems and methods having the following characteristics.

[0007] The subject of this invention is a system for supplying electrical energy to an electric vehicle having at least one high-voltage on-board network and at least one low-voltage on-board network. The system includes a high-voltage battery connected to the at least one high-voltage on-board network via an interrupting element. The high-voltage battery includes a first branch and a second branch connected in series. A first input module of a DC / DC converter is connected to the first branch, the first input module including a high-voltage bridge and connected to the first primary winding of a transformer having two primary windings and a common secondary winding. A second input module of the DC / DC converter is connected to the second branch, the second input module including a high-voltage bridge and connected to the second primary winding of the transformer having two primary windings and a common secondary winding. The output of the DC / DC converter is connected to the at least one low-voltage on-board network.

[0008] In the context of this specification, a high-voltage vehicle network is a high-voltage vehicle network having a voltage level exceeding 200V, particularly in the range of 300V to 1200V, such as 400V or 800V. A high-voltage battery is a high-voltage energy storage device having a rated output voltage in the range of 300V to 1200V, such as 400V or 800V. A low-voltage vehicle network is a low-voltage vehicle network having a voltage level less than 100V, particularly in the range of 10V to 60V, such as 12V or 48V.

[0009] The system configuration according to the invention is used to supply electrical energy to an electric vehicle, wherein the vehicle has multiple electrical components (typically power consumers or power sources). The system is arranged within the vehicle and includes a high-voltage battery or accumulator having two or more lines connected in series, each having at least one energy storage unit. Each line has at least one energy storage unit, such as a battery cell, wherein multiple energy storage units may be connected in series and / or in parallel with each other in corresponding lines.

[0010] The electrodes of the high-voltage battery are connected to the vehicle's high-voltage on-board network via interrupting elements (e.g., battery contactors). The vehicle's high-voltage on-board network includes: a high-voltage generator set, such as a motor for driving, heating, and cooling the generator set; and a charging module for charging the high-voltage battery with AC and / or DC current. The input module of the DC / DC converter is connected to the electrodes of the branches of the high-voltage battery. This input module includes a DC / AC conversion unit (high-voltage bridge) and is connected to one of the primary windings of a transformer having multiple primary windings and a common secondary winding. In one embodiment, the DC / DC converter according to the invention has two or more high-voltage bridges as input modules, a common transformer, and a common secondary side.

[0011] In one implementation of the DC / DC converter, the high-voltage bridge of the input module is constructed as a full-bridge. Other topologies may also be used depending on the power requirements and voltage variation range on the high-voltage side. In one implementation, the high-voltage bridge is implemented as a half-bridge. In another implementation, the high-voltage bridge is implemented as a resonant converter.

[0012] In one embodiment, the secondary winding of the transformer has a center tap (center tap technology) used on the secondary side. In another embodiment, an active full-bridge rectifier is used on the secondary side. In yet another embodiment, a passive or active rectifier is used. In still another embodiment, a current multiplier is used.

[0013] The energy system according to the invention is characterized by achieving higher voltage supply availability through the center tap of the high-voltage battery. Additionally, the DC / DC converter is moved before the main contactor so that the supply voltage is not disconnected in the event of a QM power consumption failure. Power supply to the low-voltage on-board network is still ensured in the event of a failure.

[0014] Two sub-groups, each with half the system voltage, are formed by a center tap of the high-voltage battery. The energy system according to the invention includes a DC / DC converter topology that can use the entire high-voltage battery or only one of the two battery groups. During normal operation, each phase directs its corresponding half of the power to the transformer. In the event of a battery failure, the remaining phase can output the full power to the low-voltage on-board network. This achieves stable grid power supply and only slightly higher component costs. Using a common transformer (including the core) offers advantages in terms of packaging and weight compared to using two fully redundant DC / DC converters.

[0015] It is feasible to place the DC / DC converter as an external component outside the energy storage device, or as an internal component inside the energy storage device and integrate it therein.

[0016] The present invention also relates to a method for supplying electrical energy to a vehicle having at least one high-voltage on-board network and at least one low-voltage on-board network, and including a high-voltage battery comprising a first branch and a second branch connected in series. In this method, at least one high-voltage on-board network is connected to the electrodes of the high-voltage battery and is supplied with electrical energy, and at least one low-voltage on-board network is connected to the output of a DC / DC converter and is supplied with electrical energy, wherein a first input module having a high-voltage bridge is connected to the first branch, and a second input module having a high-voltage bridge is connected to the second branch, wherein each of the two input modules is connected to a primary winding of a transformer having two primary windings and a common secondary winding.

[0017] During normal operation, each phase directs half of its power to the transformer. In the event of a branch (battery pack) failure, all power can be output to the low-voltage vehicle network through the remaining branches. That is, in the event of a failure in the first branch, all power is output to the low-voltage vehicle network through the second branch, and in the event of a failure in the second branch, all power is output to the low-voltage vehicle network through the first branch.

[0018] It can achieve symmetrical load regulation and battery load. In the case of asymmetrical battery charging, it can achieve a balancing function to compensate for the asymmetry between the two branches.

[0019] In one embodiment, the output voltage of the high-voltage battery has a value in the range of 200 to 1200V, for example, in the range of 400V to 800V.

[0020] If a high-voltage battery is charged in a pack, where the two lines of the high-voltage battery are connected in parallel to enable charging at half the rated voltage (e.g., 400V), then twice the power can be output to the vehicle network to operate comfort functions, such as air conditioning, when necessary.

[0021] In one implementation, the output voltage of the DC / DC converter has a value in the range of 10V to 60V, for example, in the range of 12V to 48V.

[0022] In this method, a high-voltage battery and a DC / DC or DC current / DC current converter with two independent input terminals are used. The high-voltage battery has two lines, each with at least one energy storage unit. A corresponding line of the energy storage unit and a corresponding input terminal of the DC / DC converter are connected to each other on both sides via the lines. The electrodes of the high-voltage energy storage unit provide a high-voltage voltage to at least one high-voltage circuit, and the output terminal of the DC / DC converter provides a low-voltage voltage to at least one low-voltage circuit of the vehicle.

[0023] It is possible that one implementation of this method utilizes one implementation of the proposed system.

[0024] Here, it is more feasible to provide at least one low-voltage circuit than at least one high-voltage circuit.

[0025] In this method, electrical energy can be exchanged unidirectionally or bidirectionally between the high-voltage battery circuitry or its energy storage unit and at least one component of the high-voltage vehicle network. It is possible that electrical energy is supplied from the high-voltage battery, i.e., from at least one circuitry of the high-voltage battery. Correspondingly, it is possible to use the electrical energy from at least one component to charge at least one circuitry of the high-voltage battery, or to charge the component and store the electrical energy therein. The component, for example, is configured as a motor for driving the vehicle, which, in operating mode as a motor, converts electrical energy from the high-voltage battery into mechanical energy and moves the vehicle. In operating mode as a generator, the motor, for example, converts mechanical energy into electrical energy based on motion during recovery, and the electrical energy is stored in the high-voltage battery. It is also possible that the component is configured, for example, as a fuel cell and thus as a power source, whose electrical energy can also be stored in the high-voltage battery. At least one additional component can be configured as an actuator, sensor, and / or device of the vehicle, for example, configured as at least one control device of the vehicle.

[0026] In implementing this method and system, a highly available power supply to the vehicle's low-voltage on-board network is provided through the aforementioned structure of the DC / DC converter and its connection to the high-voltage battery lines. Here, the low-voltage on-board network is supplied with electrical energy from two lines of the high-voltage battery via the DC / DC converter. The high-voltage battery lines (which may also be referred to as branches) and the input of the DC / DC converter form a parallel power supply path for components of the low-voltage on-board network, such as power consumers. Here, a possible fault in the lines will not lead to a failure in the power supply to the low-voltage on-board network, especially a complete failure, because the availability of the low-voltage on-board network is enhanced based on the parallel arrangement of the lines. The high-voltage battery can be implemented using a variable battery concept, where it is conceivable that the lines have different numbers of energy units and / or energy units of different configurations, such as battery cells and / or capacitors. Based on the parallel power supply implemented through the DC / DC converter, a fault in the input module will not lead to a failure in the power supply to the low-voltage on-board network.

[0027] It should be understood that the features described above and will be set forth below may be used not only in the corresponding combinations but also in other combinations or individually, without departing from the scope of protection of the present invention. Attached Figure Description

[0028] The present invention is schematically illustrated in the accompanying drawings according to embodiments, and is described schematically and in detail with reference to the accompanying drawings.

[0029] Figure 1 A partial diagram of an embodiment of a system according to the invention for performing an embodiment of the method according to the invention is shown in schematic diagram. Detailed Implementation

[0030] Figure 1 A partial diagram schematically illustrates an embodiment of the energy system 100 according to the present invention. The connection between the high-voltage battery 10 and the high-voltage vehicle network, the vehicle's high-voltage vehicle network, and the low-voltage vehicle network are not shown.

[0031] The high-voltage battery 10 has a first branch 11 and a second branch 12. A first input module 21 of the DC / DC converter 20 is connected to the first branch 11, and a second input module 22 of the DC / DC converter 20 is connected to the second branch 12. This implements a center tap for the high-voltage battery 10. In the illustrated embodiment, input modules 21 and 22 comprise a full bridge as a DC / AC converter. Both input modules 21 and 22 are connected to the primary side of a common transformer 23, which has two primary windings and a common secondary winding. In the illustrated embodiment, the secondary winding of transformer 23 has a center tap. The center tap is used for the secondary side of transformer 23 (center tap technology). The output of the DC / DC converter 20 is connected to the vehicle's low-voltage on-board network.

[0032] List of reference numerals in the attached diagram:

[0033] 10 Energy Storage

[0034] 11 First Branch Road

[0035] 12 Second Branch Road

[0036] 20 DC / DC converters

[0037] 21 First input module with high voltage bridge

[0038] 22 Second input module with high voltage bridge

[0039] 23. Public transformer.

Claims

1. A system (100) for supplying electrical energy to an electric vehicle, said electric vehicle having at least one high-voltage on-board network and at least one low-voltage on-board network, wherein, The system (100) includes a high-voltage battery (10) connected to the at least one high-voltage vehicle network via an interruption element. The high-voltage battery (10) includes a first branch (11) and a second branch (12) connected in series. A first input module (21) of a DC / DC converter (20) is connected to the first branch (11). The first input module includes a high-voltage bridge and is connected to the first primary winding of a transformer (23) having two primary windings and a common secondary winding. A second input module (22) of the DC / DC converter (20) is connected to the second branch (12). The second input module includes a high-voltage bridge and is connected to the second primary winding of the transformer (23) having two primary windings and a common secondary winding. The output of the DC / DC converter (20) is connected to the at least one low-voltage vehicle network.

2. The system according to claim 1, wherein, The high-voltage bridge of the first input module (21) and the second input module (22) is implemented as a full bridge.

3. The system according to claim 1, wherein, The high-voltage bridge of the first input module (21) and the second input module (22) is implemented as a half-bridge.

4. The system according to claim 1, wherein, The high-voltage bridge of the first input module (21) and the second input module (22) is implemented as a resonant converter.

5. The system according to any one of claims 1 to 4, wherein, The DC / DC converter (20) has an active or passive rectifier on the secondary side of the transformer (23).

6. The system according to any one of claims 1 to 4, wherein, The DC / DC converter (20) has an active full bridge on the secondary side of the transformer (23).

7. The system according to any one of claims 1 to 4, wherein, The DC / DC converter (20) has a current multiplier on the secondary side of the transformer (23).

8. The system according to any one of claims 1 to 4, wherein, The secondary winding of the transformer (23) has a center tap, and the DC / DC converter (20) uses the center tap on the secondary side of the transformer (23).

9. A method for supplying electrical energy to an electric vehicle, the electric vehicle having at least one high-voltage on-board network and at least one low-voltage on-board network, and including a high-voltage battery (10), the high-voltage battery including a first branch (11) and a second branch (12) connected in series, wherein, At least one high-voltage on-board network is connected to the electrodes of the high-voltage battery (10) and is supplied with electrical energy, and at least one low-voltage on-board network is connected to the output of a DC / DC converter (20) and is supplied with electrical energy, wherein a first input module (21) with a high-voltage bridge is connected to the first branch (11), and a second input module (22) with a high-voltage bridge is connected to the second branch (12), wherein each of the two input modules (21, 22) is connected to a primary winding of a transformer (23) having two primary windings and a common secondary winding.

10. The method according to claim 9, wherein, In the event of a failure of the first branch (11), all power is output to the low-voltage vehicle network through the second branch (12), and in the event of a failure of the second branch (12), all power is output to the low-voltage vehicle network through the first branch (11).

Images