Brake resistance system for a vehicle and vehicle with a brake resistance system

Abstract

The present invention provides a braking resistor system (10) for a vehicle, comprising at least one electronic unit (13) including an inverter (12), power electronics and / or a control unit, and a high-load resistor unit (11) electrically coupled to the electronic unit (13) and having a housing (16), wherein the electronic unit (13) and the high-load resistor unit (11) are arranged adjacent to each other and are electrically coupled via a phase-carrying busbar (23), and wherein a cooling device (14) is provided for the joint cooling of the high-load resistor unit (11) and the electronic unit (13), as well as a vehicle with such a braking resistor system (10).

Description

[0001] The present invention relates to a braking resistance system for a vehicle and a vehicle with a braking resistance system. State of the art

[0002] Braking resistor systems are systems used in the electric drives of electric vehicles to safely dissipate excess electrical energy generated during braking. Such braking resistor systems typically include a high-power resistor that converts excess electrical energy into heat, an inverter that converts direct current (DC) to alternating current (AC) and is integrated into power electronics that control the current to the braking resistor, cooling systems for the resistor (e.g., heat sinks, fans, or liquid cooling) to dissipate the heat generated, and control and monitoring units that monitor and control the operation of the braking resistor system, for example, to prevent overheating. When an electric vehicle or machine decelerates, the electric motor acts as a generator, converting kinetic energy into electrical energy.Normally, electrical energy is fed back into the battery. However, if the battery is fully charged or the energy cannot be fed back quickly enough, the energy is diverted via the braking resistor system. The excess energy is then diverted to the high-load resistor and converted into heat, which is dissipated via the cooling systems to prevent overheating of the resistor and the surrounding environment.

[0003] In known braking resistor systems, the power electronics and high-power resistor have separate cooling systems, requiring significant assembly effort during manufacturing. Furthermore, the power electronics are typically connected to the high-power resistor via cables on the AC side. Shield currents occur along these cables, resulting in shield current losses that lead to temperature increases and consequent efficiency losses in the power electronics, thus affecting the electromagnetic behavior of the electric machine.

[0004] The object of the present invention is to provide a braking resistor system that requires less assembly effort and in which the efficiency of the current flow between power electronics and high-power resistor can be increased. Disclosure of the invention

[0005] The present invention provides a braking resistance system in a vehicle according to claim 1 and a vehicle with a braking resistance system with such a braking resistance system according to claim 9.

[0006] Preferred further training courses are the subject of the subclaims. Advantages of the invention

[0007] The idea underlying the present invention is to provide a braking resistor system for a vehicle, comprising at least one electronic unit including an inverter, power electronics and / or a control unit, and a high-load resistor unit electrically coupled to the electronic unit and having a housing, wherein the electronic unit and the high-load resistor unit are arranged adjacent to each other and are electrically coupled via a busbar, and a cooling device is provided for the joint cooling of the high-load resistor unit and the electronic unit.

[0008] The arrangement according to the invention, with the electronic unit and high-power resistor being located adjacent to each other and cooled together by the cooling device, enables a more compact design of the entire unit with shorter cable runs in both the cooling and electrical systems and a reduced number of cable connections. The design envisions the use of busbars as a replacement for the phase cables used in conventional systems. Busbars are designed as rigid metallic conductors, for example made of copper or aluminum, with a flat or rectangular shape, over which the current phases are routed. This design initially allows for simpler installation. Busbars also generally have a higher current-carrying capacity per cross-section compared to cables, with the larger surface area compared to cables improving current flow in the high-power resistor.Furthermore, the AC-side shield currents and shield current losses occurring in cables are reduced, and the resulting heat input into the power electronics is decreased. This increases the efficiency of the electric drive. The close proximity of the components and the short distances between the electronic unit and the high-power resistor, bridged by the busbar, also improve the electromagnetic behavior of the braking resistor system. The braking resistor system according to the invention thus advantageously improves the efficiency of the electric drive and increases operational reliability. Moreover, it is advantageous that the installation space requirements are optimized compared to conventional systems, as conventional phase cables with their corresponding bending radii are completely eliminated.

[0009] According to a preferred embodiment of the braking resistor system, the high-power resistor unit has at least two resistors for connection to the busbar. Among numerous other advantages, the use of at least two resistors results in a more even distribution of the generated heat. This reduces the thermal stress on individual resistors and also decreases the risk of hotspots that can lead to overheating and potential failures. The more even heat distribution facilitates the cooling of the resistors, as the cooling capacity of the cooling device is better utilized and heat dissipation can be more effective. Furthermore, the presence of at least two resistors provides redundancy in the high-power resistor unit. Additionally, the overall power consumption of the system is increased, allowing a greater amount of excess energy to be absorbed and converted into heat.This is particularly advantageous in applications where large amounts of energy need to be dissipated in a short time, such as during intensive braking in electric vehicles. The use of multiple resistors can also help to smooth current peaks and voltage fluctuations, as the energy is distributed and dissipated more evenly. This contributes to the stability of the entire electrical system. Multiple resistors, especially those in parallel, can help to reduce the overall inductance of the system, thereby improving the system's response time and increasing its efficiency. Embodiments are also conceivable and equally covered by the invention, in which three or more resistors are provided in the high-power resistor unit. Preferably, the resistors can be connected in parallel or in series.The type of interconnection (parallel or serial) is determined in particular by a software control implemented in the system, which is not the subject of the present invention.

[0010] According to a preferred embodiment of the braking resistor system, in one installation state the electronic unit is arranged on the housing, preferably above the high-power resistor unit. This offers advantages in terms of installation space and allows for a compact device that can also be integrated into existing systems. The more compact design reduces material usage during manufacturing and the weight of the overall unit, thus lowering manufacturing costs. Furthermore, the conductor paths to be bridged by the busbar and in the cooling system or by the cooling device are shortened, resulting in increased efficiency in the entire system and shorter response times. The invention also encompasses the arrangement of the high-power resistor unit and the electronic unit in a common, modular housing or in separate housings, particularly those that are separably connected.

[0011] According to a preferred embodiment of the braking resistor system, the cooling device includes a cooling line through which a cooling medium flows, forming a cooling circuit. This offers advantages in the configuration of the braking resistor system. Since the cooling device serves to cool both the high-power resistor unit and the electronic unit, shorter line paths and a reduced number of inlet and outlet connections result in more efficient heat dissipation. This not only prevents overheating of the electronic unit but also ensures constant resistance performance.

[0012] The cooling system can be operated with a variety of cooling media. It is advantageous to choose a liquid as the cooling medium, since liquid cooling is generally more effective than, for example, air cooling due to its higher heat capacity.

[0013] According to a preferred embodiment of the braking resistor system, the cooling device has an inlet port and an outlet port for the cooling medium, each connected to the cooling line. The inlet port and the outlet port are located in the housing, preferably on the same side of the housing. This achieves a compact system design through the direct connection of the high-power resistor unit and the electronic unit mounted on it to the cooling circuit.

[0014] According to a preferred embodiment of the braking resistor system, the inlet and outlet connections are arranged on a surface of the housing facing the electronics unit. This offers advantages in terms of installation space and integration possibilities. Positioning the inlet and outlet connections within the housing reduces the required installation space, as additional external lines and connections are avoided. By arranging the inlet and outlet connections on the surface of the housing facing the electronics unit, the available space is used optimally. This results in a more compact and efficient system design. Having the inlet and outlet connections on a single surface of the housing facilitates the integration of the electronics unit into the cooling system, thereby reducing assembly effort and simplifying the overall design.Furthermore, the number of connection points is reduced, as only a single pair of connections (inlet and outlet) is required for both the high-power resistor unit and the electronics unit, through which the entire cooling circuit is routed. Integrating the cooling circuit also improves cooling performance and efficiency by positioning the inlet and outlet connections on the housing surface facing the electronics unit. This allows the cooling medium to circulate simultaneously through both the electronics unit and the high-power resistor unit, thereby improving heat dissipation and the overall cooling performance of the system.

[0015] According to a preferred embodiment of the braking resistor system, the cooling device has a branch line for the cooling medium, which is connected to the cooling line and / or directly to the inlet connection and passes through the electronic unit. The fact that separate inlet and outlet connections are not required in the electronic unit and the high-power resistor unit offers further advantages of the braking resistor system according to the invention. For example, it has fewer interfaces between the cooling device and the electronic unit or high-power resistor unit, and the cooling medium can circulate more effectively, thus increasing the efficiency of the cooling circuit. The branch line, which carries the cooling medium directly through the electronic unit, enables targeted cooling of the components integrated within it. This ensures that the electronic components are optimally cooled and heat is efficiently dissipated.The branch line enables optimal distribution of the cooling medium within the system. This ensures that all relevant components are adequately cooled without over- or under-cooling. When integrating the branch line into the inlet connection, a diversion of the cooling medium flow to the electronics unit can be provided there, further simplifying the design of the cooling system. The branch line can also be arranged so that, after passing through the electronics unit, it leads directly into the outlet connection or, prior to that, into the main cooling line coming from the high-power resistor unit.

[0016] According to a preferred embodiment of the braking resistor system, a throttling device for the cooling medium flow is provided in the branch line. The throttling device in the branch line has the advantage of enabling precise control of the cooling medium flow, even when it is connected to the cooling medium flow of the overall system. This allows the flow rate of the cooling medium to be adjusted as needed to ensure optimal cooling of the electronic unit. The use of a branch line and a throttling device allows for a modular design of the cooling system and facilitates the adaptation and optimization of the system for different applications and performance requirements.

[0017] According to a preferred embodiment of the braking resistor system, a control device, in particular an NTC thermistor, is provided for controlling the cooling device. Integrating a control device, especially an NTC thermistor (Negative Temperature Coefficient Thermistor), for controlling the cooling device in a braking resistor system offers numerous advantages. The control device enables precise temperature monitoring and control. It also allows for a shutdown for safety reasons in the event of overheating. The control / regulation of the power output is achieved, in particular, by setting a setpoint within the system and measuring the current and voltage. The preferably used NTC thermistor enables the precise measurement of the temperature of the high-power resistor unit and other components.Since the resistance of the NTC thermistor decreases with increasing temperature, temperature changes can be detected quickly and precisely. Continuous monitoring and control of the coolant supply allows the cooling to be adjusted exactly to the current demand. This prevents unnecessary cooling and thus leads to improved overall system performance, as the components always operate within their optimal temperature range.

[0018] The invention also relates to a vehicle with a braking resistor system as described above, wherein the braking resistor system is integrated into the vehicle's high-voltage traction network and the vehicle is configured, in particular, as a battery electric vehicle (BEV), fuel cell electric vehicle (FCEV), hybrid electric vehicle (HEV), or plug-in hybrid electric vehicle (PHEV). Integrating a braking resistor system according to the invention into a vehicle's high-voltage traction network offers significant advantages, particularly in various types of electrified vehicles (BEV, FCEV, HEV, PHEV), such as more efficient energy use and distribution, and reduced battery load during high recuperation. The braking resistor system also improves the vehicle's braking performance by dissipating excess energy quickly and safely.Integration into the high-voltage traction network enables efficient thermal management, minimizing overheating and associated risks.

[0019] With the described cooling device, including targeted cooling through branch lines and control of the cooling medium flow, the system can be adapted to different thermal requirements.

[0020] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings. Brief description of the drawings

[0021] The present invention will be explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing.

[0022] They show: Fig. 1 a schematic representation of a section of the braking resistance system according to an embodiment of the present invention; and Fig. 2 a schematic representation of the cooling device in a braking resistor system according to an embodiment of the present invention.

[0023] In the figures, identical reference symbols denote identical or functionally equivalent elements.

[0024] Fig. Figure 1 shows a schematic representation of a section of the braking resistor system 10 according to an embodiment of the present invention in an electric vehicle. This system comprises, in addition to other elements not shown, a high-power resistor unit 11 and an electronic unit 13 comprising an inverter 12, power electronics, and / or a control unit. The high-power resistor unit 11 is housed in a casing 16, on the surface 24 of which the electronic unit 13 is arranged. The arrangement shown results in a compact design of the braking resistor system 10 with short electrical transmission paths between the electronic unit 13 and the high-power resistor unit 11.

[0025] The high-power resistor unit 11 and the electronic unit 13 have a cooling device 14 which provides a cooling circuit 15 that serves to cool both the high-power resistor unit 11 and the electronic unit 13. In the illustrated embodiment according to the invention, the high-power resistor unit 11, which is housed in a casing 16, is integrated into the cooling device 14. The cooling device 14 has several cooling lines 17 arranged in the casing 16, which loop through the casing 16. The resistors 18a, b are located in the Fig. 2 visible loops 25 embedded to ensure efficient heat dissipation and thus cooling of the resistors 18a, b.

[0026] An inlet port 19 is arranged in the housing 16. This port is connected to the cooling lines 17 and supplies the cooling medium flowing through the cooling unit 14. The electronic unit 13 is also cooled via the cooling unit 14, which has a branch line 20 for this purpose. The cooling medium is supplied to the electronic unit 13 via the coolant port 27 provided there. The inlet port 19 is positioned close to the electronic unit 13 in the housing 16, on the left side in the illustration. The short branch line 20 connected to the inlet port 19 is in fluidic contact with the cooling medium flow of the cooling unit 14, thus eliminating the need for a separate cooling unit with a separate cooling medium flow for the electronic unit 13. This allows for a more compact overall design and a significant reduction in the number of separate connections.Since the cooling requirement of the electronic unit 13 is lower than that of the high-power resistor unit 11, only a reduced flow of cooling medium needs to be supplied. Therefore, a throttle device 21 is integrated into the branch line 20 to regulate the flow of cooling medium and ensure optimal cooling of the electronic unit 13. Cooling of the electronic unit 13 is also achieved by its placement on the housing 16, which contains the majority of the cooling device 14. If the housing 16 is made of a material with high thermal conductivity, such as aluminum or an aluminum alloy, some of the heat emitted by the electronic unit 13 is also dissipated by the housing 16.

[0027] The cooling circuit formed by the cooling device 14 is associated with an outlet port 22, through which the cooling medium flows out of the cooling device 14 and is, for example, supplied to a heat exchanger. The outlet port 22 is located on the same housing side 30 as the inlet port 19 and in Fig. 1 shown identically to this.

[0028] In the exemplary embodiment, the high-power resistor unit 11 comprises two resistors 18a, b, which are designed as high-power resistors. The resistors 18a, b are connected to the electronic unit 13 via a phase-carrying busbar 23. The busbar 23 is designed as a rigid metallic conductor, for example made of copper or aluminum, with a flat or rectangular shape. This design facilitates simpler installation. The adjacent arrangement and the short distances to be bridged by the busbar 23 between the electronic unit 13 and the high-power resistor unit 11, as well as the partial arrangement of the busbar 23 within the two units, also improve the electromagnetic behavior of the braking resistor system 10. The braking resistor system according to the invention thus advantageously improves the efficiency of the electric drive and increases operational reliability.

[0029] In the illustrated embodiment of the braking resistor system 10, the high-power resistor unit 11 has at least two resistors 18a, b for connection to the busbar 23, without limiting the invention thereto. The use of at least two resistors 18a, b distributes the generated heat more evenly and reduces the thermal load on the individual resistors 18a, b. This more even heat distribution facilitates the cooling of the resistors 18a, b, as the cooling capacity is better utilized and heat dissipation can be more effective. Furthermore, the overall power consumption of the system is increased, allowing a larger amount of excess energy to be absorbed and converted into heat. This is particularly advantageous in applications where large amounts of energy need to be dissipated in a short time, such as during intensive braking in electric vehicles.The use of multiple resistors 18a, b can also help to smooth current peaks and voltage fluctuations, as the energy is distributed and dissipated more evenly. This further contributes to the stability of the entire electrical system. Multiple resistors 18a, b, especially those in parallel, can help to reduce the overall inductance of the system, thereby improving the system's response time and increasing its efficiency. It is also conceivable to include embodiments in which three or more resistors 18a, b, particularly variably connected via a control concept integrated and optimized in separate control electronics (not shown here), are provided in the high-power resistor unit 11.The conductor rail 23 carries the phases U, V and W of the electrical energy via separate rail sections 23a, b, c into the high-load resistance unit 11, in which the electrical energy is converted into heat and this is dissipated via the cooling device 14.

[0030] Fig. Figure 2 shows a schematic representation of the cooling device 14 in a braking resistor system 10 according to the invention. The cooling device 14 is arranged in a housing 16, which also contains the components described in Figure 2. Fig. 2 not recognizable, but in Fig. The resistors 18a, b shown in Figure 1 are embedded between the cooling lines 17. The cooling device 14 has a plurality of cooling lines 17 grouped into two subunits 26a, b, which run through the housing 16 as loops 25. A cooling medium is supplied to the cooling device 14 via the inlet port 19 and discharged from it via the outlet port 22. The inlet port 19 and outlet port 22 are arranged on the same housing side 30 of the cooling device 14 and are congruent or substantially congruent with the ones concealed here by the housing 16, but in Fig. 1 visible coolant connections 27 above the cooling device 14 on the housing 16 as in Fig. 1. The assembled electronic unit 13 is shown. The electronic unit 13 is in Fig. 2 is also concealed by the cooling device 14 or the housing 16. Inlet port 19 and outlet port 22 are in Fig. 2 are only indicated by reference and are located in the main surface 24 of the cooling device 14, which faces away from the viewer and on which the electronic unit 13 is also located when installed (see below). Fig. 1) This allows the cooling of the electronic unit 13 to be integrated into the cooling device 14 and the cooling medium flow. As in connection with Fig. As described in Figure 1, the cooling device 14 has a branch line 20 integrated into the inlet connection 19, which is led to the electronic unit 13 and connected to the coolant connection 27 provided there (see Figure 1). Fig. 1) The branch line 20 is also connected to the outlet connection 22, through which the cooling medium is discharged from the cooling device 14.

[0031] Between the cooling lines 17, they are only in Fig.The resistors 18a, b shown in Figure 1 are embedded within the housing 16 and are thus in thermal contact with the cooling lines 17. As previously described, the electronic unit 13, located on the housing 16, is in fluidic contact with the cooling device 14. The housing 16 also contains a control unit 28 in the form of two NTC thermistors 29a, b, primarily for controlling the safety / overload shutdown and optimizing the flow rate of the high-power resistor unit 11 and the cooling device 14. These NTC thermistors are positioned in the cooling device 14 near the outlet connection 22. The NTC thermistors 29a, b measure the temperature of the cooling medium and adjust the cooling power or the current supplied to the resistors 18a, b accordingly.The design according to the invention allows the efficiency of the braking resistor system 10 to be increased and thereby the number of resistors 18a, b to be reduced, resulting in a more compact design of the entire unit.

[0032] Although the present invention has been fully described above with reference to the preferred embodiment, it is not limited to this embodiment but can be modified in many different ways.

Claims

[1] Braking resistor system (10) for a vehicle, comprising at least one electronic unit (13) comprising an inverter (12), power electronics and / or a control unit and a high-power resistor unit (11) electrically coupled to the electronic unit (13) and having a housing (16), characterized by , that the electronic unit (13) and the high-power resistor unit (11) are arranged adjacent to each other and are electrically coupled via a busbar (23) and a cooling device (14) is provided for the joint cooling of the high-power resistor unit (11) and the electronic unit (13). [2] Braking resistance system (10) according to claim 1, characterized by , that the high-load resistance unit (11) has at least two resistors (18a, b) for connection to the busbar (23), which is in particular phase-carrying. [3] Braking resistance system (10) according to claim 1 or 2, characterized by, that in an installed state the electronic unit (13) is arranged on the housing (16), preferably above the high-power resistor unit (11). [4] Braking resistance system (10) according to any one of the preceding claims, characterized by , that the cooling device (14) has a cooling line (17) forming a cooling circuit through which a cooling medium can flow. [5] Braking resistance system (10) according to claim 4, characterized by , that the cooling device (14) has an inlet port (19) connected to the cooling line (17) and an outlet port (22) for the cooling medium, wherein the inlet port (19) and the outlet port (22) are arranged in the housing (16). [6] Braking resistance system (10) according to claim 5, characterized by , that the inlet port (19) and the outlet port (22) are arranged in a surface (24) of the housing (16) facing the electronic unit (13). [7] Braking resistance system (10) according to one of claims 5 or 6, characterized by , that the cooling device (14) has a branch line (20) for the cooling medium connected to the cooling line (17) and / or the inlet connection (19) and routed through the electronic unit (13). [8] Braking resistance system (10) according to claim 7, characterized by , that a throttling device (21) for the cooling medium flow is provided in the branch line (20). [9] Braking resistance system (10) according to any one of the preceding claims, characterized by , that a control device (28), in particular an NTC thermistor (29a, b), is provided for controlling the high-load resistance unit (11) and the cooling device (14), in particular for controlling a safety and / or overload shutdown and a volume flow of the high-load resistance unit (11) and the cooling device (14). [10] Vehicle with a braking resistance system (10) according to any one of claims 1 to 9, characterized by , that the braking resistance system (10) is integrated into a high-voltage traction network of the vehicle, wherein the vehicle is in particular designed as a battery electric vehicle (BEV), fuel cell vehicle (FCEV), hybrid electric vehicle (HEV) or plug-in hybrid electric vehicle (PHEV).

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