Power electronics unit for a vehicle

Abstract

The present invention relates to a power electronics unit (1) for a vehicle (2) comprising: a housing (3); a partition (4) which divides the housing (3) into a disturbance sink area (5) and a disturbance source area (6) and is designed for electromagnetic decoupling of the disturbance sink area (5) from the disturbance source area (6); a high-voltage power electronics unit (8) within the disturbance source area (6); a printed circuit board (9) which is arranged at least partially within the disturbance sink area (5), wherein a low-voltage connection (10) for low-voltage signals (11) is arranged on the printed circuit board within the disturbance sink area (5), wherein the low-voltage signals (11) are input to and output from a higher-level vehicle system (7) of a vehicle (2), and wherein a battery connection (12) of the power electronics unit (1) is arranged on the printed circuit board within the disturbance sink area (5).The present invention further relates to a vehicle (2) with a battery (21), an electric motor and a power electronics unit (1).

Description

[0001] The present invention relates to a power electronics unit for a vehicle. Furthermore, the present invention relates to a vehicle with a power electronics unit.

[0002] Both pure electric vehicles and hybrid vehicles are known in the prior art, which are either fully or partially powered by one or more electric machines. These vehicles have electrical energy storage devices, preferably in the form of rechargeable batteries, to provide the electrical energy required for the electric machines. Typically, these batteries are designed as DC voltage sources, while the electric machines require AC voltage. For this reason, power electronics units such as traction converters are commonly used between the battery and the electric machine in electric and hybrid vehicles to provide the necessary voltage conversion.

[0003] Power electronics units typically comprise high-voltage power electronics, which include several semiconductor switching elements. These semiconductor switching elements are transistors, such as MOSFETs or IGBTs, usually arranged in half-bridge configurations. During operation, high-frequency switching occurs to generate multiple time-shifted phase currents of an alternating current (AC) from a direct current (DC) applied to the half-bridges.

[0004] The high-frequency switching operations in power electronics units lead to the generation of electromagnetic interference (EMI). This EMI poses a challenge because it can disrupt the functionality of the electronic components. Furthermore, it complicates compliance with electromagnetic compatibility (EMC) standards, which are particularly important for ensuring operational reliability in vehicles.

[0005] In this context, German patent application DE 2020 14 101 689 U1 describes an electric drive system for an electric vehicle. The drive system comprises a housing with an interior divided into multiple compartments. The drive system further comprises power conversion devices, each arranged in the partitioned compartments of the housing. The drive system also includes a connecting rail formed on a surface of the housing for electrically connecting the power conversion devices and a battery. Finally, the drive system includes adapters designed to connect the connecting rail to the power conversion devices, each adapter comprising an inner and an outer surface.The inside of the adapter is provided with conductor elements configured to be electrically connected to the electrodes of the power conversion devices when the electrodes are inserted. The outside of the adapter is provided with shielding elements that cover the conductor elements to shield against noise generated by the power conversion devices. Each of the power conversion devices comprises a high-voltage circuitry unit and a low-voltage circuitry unit. The high-voltage circuitry unit and the low-voltage circuitry unit are each covered with shielding panels and spaced apart from each other within each compartment.

[0006] Mitigating electromagnetic interference (EMI) in electric vehicles often presents a challenge, as EMI frequently occurs on the power supply of the power electronics units. These disturbances cannot be completely eliminated using conventional methods. Therefore, the use of shielded cables is necessary to ensure effective shielding against this interference. By using such shielded cables, electromagnetic compatibility can be ensured in accordance with the required standards, guaranteeing the functionality and safety of the vehicles.

[0007] A disadvantage of previous approaches is that the shielded cables used to suppress electromagnetic interference on the power supply of the power electronics units are comparatively expensive. This leads to significant cost increases, as high-quality materials and special shielding techniques are required. Additionally, the need for these shielded cables increases the size of the electrical systems, making integration into compact vehicle designs more difficult. Furthermore, the additional material of the shielded cables contributes to increased weight, which is particularly detrimental in electric vehicles. Moreover, negative interactions between inverter modules can be reduced, and the inverter's immunity can be improved.

[0008] Based on this, the object of the present invention is to provide an approach for effectively damping electromagnetic interference from power electronics units.

[0009] To solve this problem, the present invention relates in a first aspect to a power electronics unit for a vehicle, comprising: - a case; - a boundary which divides the housing into a disturbance sink area and a disturbance source area and is designed for electromagnetic decoupling of the disturbance sink area from the disturbance source area (6); - high-voltage power electronics within the interference source area; - a printed circuit board which is at least partially located within the interference sink area, wherein a low-voltage connection for low-voltage signals is arranged on the printed circuit board within the interference sink area, wherein the low-voltage signals enter and exit a higher-level vehicle system of a vehicle, and wherein a battery connection of the power electronics unit is arranged on the printed circuit board within the interference sink area.

[0010] In another aspect, the present invention relates to a vehicle with an electric motor, a battery and a power electronics unit as previously described, wherein - the high-voltage power electronics of the power electronics unit includes at least one commutation cell and busbars for supplying voltage to the commutation cell; and - the battery connection of the power electronics unit is electrically connected to the vehicle's battery via unshielded cables.

[0011] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention.

[0012] The invention relates to a power electronics unit for a vehicle. The power electronics unit comprises a housing. It also includes a partition that divides the housing into a disturbance sink area and a disturbance source area, and is designed for electromagnetic decoupling of the disturbance sink area from the disturbance source area. Furthermore, the power electronics unit comprises high-voltage power electronics within the disturbance source area. The power electronics unit also includes a printed circuit board that is at least partially located within the disturbance sink area. A low-voltage connection for low-voltage signals is arranged on the printed circuit board within the disturbance sink area, with the low-voltage signals being input to and output from a higher-level vehicle system.Within the interference suppression area on the circuit board, a battery connection for an input current of the power electronics unit is located. In particular, all outputs to the vehicle and to the battery are located within the interference suppression area.

[0013] The printed circuit board can also be multi-part or comprise several individual sub-circuit boards.

[0014] The high-voltage power electronics are located within the interference source area of ​​the power electronics unit and are designed to handle high-voltage signals, particularly alternating voltages. The components of the high-voltage power electronics generate electromagnetic fields that can interfere with other electronic systems and thus constitute interference sources. These interference sources include, in particular, semiconductor switching elements, such as MOSFETs and IGBTs arranged in half-bridge configurations, DC link capacitors, power modules that handle high currents and voltages, as well as commutation cells and DC-DC converters. These components generate disruptive electromagnetic fields due to their high power densities and steep signal edges.

[0015] An advantage of this design is that the power electronics unit is divided into a disturbance sink area and a disturbance source area by the inventive partitioning, thereby achieving electromagnetic decoupling of the two areas. This decoupling protects the sensitive low-voltage components in the disturbance sink area from the electromagnetic interference emanating from the high-voltage power electronics in the disturbance source area. This results in increased reliability and stability of the low-voltage signals necessary for communication with the higher-level vehicle system.

[0016] In a preferred embodiment, the boundary comprises an electrically conductive shielding plate. This shielding plate is arranged between the interference source area and the interference sink area and represents an effective and cost-efficient barrier solution. In further embodiments, the boundary can additionally or alternatively include optocouplers, filters, inductive components, separation channels on the printed circuit board, shielding vias on the printed circuit board, and / or galvanic isolation elements (spacers).

[0017] In a preferred embodiment, the printed circuit board (PCB) has a ground plane which is connected to the shielding plate via at least one decoupling capacitor. The advantage here is that the PCB's ground plane provides additional shielding, thus enabling improved electromagnetic decoupling. The use of decoupling capacitors ensures that high-frequency interference is diverted to ground or the chassis, thereby protecting the integrity of the low-voltage signals on the PCB.

[0018] In a preferred embodiment, the ground plane faces the shielding plate. The advantage here is that this creates an additional shield that protects the printed circuit board elements. This arrangement attenuates the electromagnetic coupling between the printed circuit board and the sources of interference.

[0019] In a preferred embodiment, the low-voltage connection and the battery connection are arranged within a connection area on the printed circuit board in an insulated manner. In this preferred embodiment, the term "insulated" specifically means that the connector area is spatially separated from other components of the printed circuit board. This insulation thus contributes to improved electromagnetic decoupling.

[0020] In a preferred embodiment, the boundary comprises filter elements arranged on the printed circuit board for attenuating common-mode and / or differential-mode interference from the power supply of the high-voltage power electronics. Since the power supply is connected to the high-voltage power electronics, it is particularly susceptible to electromagnetic interference. The filter elements effectively reduce this interference, which directly improves the power supply to the power electronics unit. This increases electromagnetic compatibility and improves the reliability of the entire power electronics unit.

[0021] In a preferred embodiment, the high-voltage power electronics comprise switching components, in particular semiconductor switching elements and / or DC link capacitors and / or inductive components, in particular transformers. The advantage here is that the high-voltage power electronics, through the use of these switching components, enable efficient and stable energy conversion.

[0022] In a preferred embodiment, the printed circuit board (PCB) includes output signal conductors that carry the voltage supply for the high-voltage power electronics. Furthermore, in this embodiment, the PCB includes low-voltage conductors that carry the low-voltage signals. The separation also comprises separation channels arranged on the PCB to isolate the output signal conductors from the low-voltage conductors and / or shielding elements arranged on the PCB to shield the output signal conductors from the low-voltage conductors. The advantage here is that the separation channels and the shielding elements on the PCB enable effective isolation or shielding of the high-voltage output signal conductors from the low-voltage conductors. This reduces electromagnetic interference between the high- and low-voltage signals, improves signal integrity, and increases the reliability of the entire power electronics unit.

[0023] In a preferred embodiment, the shielding plate and / or the housing is made of metallic sheet metal, in particular copper or aluminum sheet metal, amorphous metal, and / or coated metal. These materials offer good electrical conductivity, which ensures effective shielding against electromagnetic interference. Furthermore, a Faraday cage can be formed that completely encloses the interference source area. This improves the electromagnetic compatibility of the entire power electronics unit and increases the reliability of the electronic components in the vehicle.

[0024] In a preferred embodiment, both the battery connection and the low-voltage connection comprise a connector. This simplifies the installation and replacement of the power electronics unit, as the connections can be made or disconnected quickly and reliably. Furthermore, connectors ensure a stable and reliable electrical connection, which is essential for the transmission of both high-voltage and low-voltage signals.

[0025] In a preferred embodiment, the enclosure comprises several shielding plates within the housing, which divide the housing into multiple interference source areas and interference sink areas, each shielding plate being designed to electromagnetically decouple the respective interference source areas from the interference sink areas. This allows multiple interference source areas, containing different high-voltage power electronic components, and interference sink areas to be formed and effectively shielded within the same power electronics unit. This enables a more flexible arrangement of the electronic components and improves the electromagnetic compatibility of the entire power electronics unit.

[0026] In a preferred embodiment, the printed circuit board (PCB) has a modular design, wherein the PCB can be detachably arranged on the shielding plate, mechanically and / or electrically, in particular by means of snap-fit, plug-in, or screw connections. The modular design makes it possible to adapt the PCB to the requirements of the power electronics unit. This increases production flexibility, as components can be easily added, removed, or replaced without having to replace the entire power electronics unit.

[0027] The invention further relates to a vehicle with an electric motor and a power electronics unit as described above, wherein the high-voltage power electronics of the power electronics unit comprises at least one commutation cell and busbars for supplying voltage to the commutation cell, and the battery connection of the power electronics unit is electrically connected to the vehicle's battery by means of unshielded cables.

[0028] The vehicle according to the invention also has the advantages described in connection with the power electronics unit according to the invention.

[0029] Another advantage is that the high-voltage power electronics of the power electronics unit, through the integration of commutation cells and busbars, ensure an efficient voltage supply. This enables the conversion of the high voltage for the operation of the electric motor.

[0030] Another advantage is that the power electronics unit, thanks to its effective shielding, isolates all critical electromagnetic interference within its housing. This allows the use of unshielded cables for the electrical connection between the battery and the battery. This simplifies the wiring and reduces material and manufacturing costs. At the same time, the electromagnetic compatibility of the system is maintained, as the internal shielding of the power electronics unit effectively prevents electromagnetic interference from escaping via the cables and thus interfering with other electronic systems in the vehicle. This results in a more robust and cost-effective system architecture.

[0031] The invention is described and explained in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings. These show: Fig. 1 a schematically simplified representation of a vehicle according to the invention in a side view, comprising a power electronics unit and an electric motor; Fig. 2 a schematic representation of a first embodiment of a power electronics unit according to the invention; Fig. 3a a schematic representation of the division of a second embodiment of a power electronics unit according to the invention; and Fig. 3b a schematic representation of the division of a third embodiment of a power electronics unit according to the invention.

[0032] Fig. Figure 1 shows a schematically simplified side view of a vehicle 2 according to the invention, comprising a power electronics unit 1, a battery 21, and an electric motor (not shown). The power electronics unit 1 has a battery connection which is electrically connected to the battery 21 of the vehicle 2 by means of unshielded cables 20.

[0033] Fig. Figure 2 shows a schematic representation of a first embodiment of a power electronics unit 1 according to the invention. In this embodiment, the power electronics unit 1 has an electrically conductive housing 3 made of aluminum. By means of a shield 4, the housing 3 is divided into an interference sink area 5 and an interference source area 6.

[0034] In the illustrated embodiment, the shielding 4 comprises an electrically conductive shielding plate. The geometry of the shielding plate can be adapted to the corresponding contour of the housing 3. Reinforcements can be incorporated to increase the rigidity of the shielding plate.

[0035] Interference source area 6 comprises a high-voltage power electronics unit 8 with a commutation cell 17 and components primarily responsible for generating electromagnetic interference. These include, in particular, power semiconductors (especially transistors and / or diodes). The high-voltage power electronics unit 8 is connected directly (so-called integrated shaft) or indirectly via high-voltage cables to the electric motor of the vehicle 2 to supply it with alternating current. These components are arranged in interference source area 6 such that their electromagnetic emissions are shielded. The commutation cell 17 is supplied with voltage via busbars 19, which are also located in interference source area 6. Optionally, an additional filter (not shown) may be present in this area.

[0036] In contrast, the interference sink area contains 5 sensitive electronic components that could be affected by electromagnetic interference. These include, for example, the control electronics for the high-voltage power electronics 8 with associated signal conductors.

[0037] By dividing the power electronics unit 1 into these two defined areas by means of the partition 4, an effective reduction of electromagnetic interference is achieved. The housing 3 (e.g., made of aluminum) not only ensures mechanical stability but also provides additional shielding against outgoing electromagnetic radiation. Thus, the partition 4 and the housing 3 electromagnetically decouple the interference sink area 5 from the interference source area 6.

[0038] Furthermore, the exemplary embodiment includes a printed circuit board 9 which is arranged entirely within the interference sink area 5. The printed circuit board 9 has a grounded ground plane 14 on its underside.

[0039] The ground plane 14 of the printed circuit board 9 is designed as a continuous copper layer that serves as a feedback path for electrical signals. It helps to reduce electromagnetic interference by acting as additional shielding. The ground plane 14 faces the shielding plate 4 and is connected to the shielding plate 4 via a decoupling capacitor 15.

[0040] A low-voltage connection 10 for low-voltage signals 11 is arranged on the circuit board 9. The low-voltage signals 11 are supplied from a higher-level vehicle system 7, for example, from an on-board electrical system; they include, in particular, control and regulation signals as well as measurement signals. The low-voltage signals 11 serve to control and regulate the components of the high-voltage power electronics 8. Furthermore, the higher-level vehicle system 7 is supplied by low-voltage signals 11 from the power electronics unit 1. In this embodiment, the low-voltage signals 11 are in the range of 0 to 24 V. According to the invention, a reduction in shielding or even a complete elimination of shielding of the corresponding signal conductors is possible.

[0041] A battery connection 12 for an input current connection 13 of the power electronics unit 1 is also arranged on the circuit board 9. In this embodiment, the voltage is, for example, in the range of 60 to 800 V.

[0042] In this embodiment, the boundary 4 has filter elements 16 arranged on the circuit board 9, which are designed to dampen common-mode and / or differential-mode interference of the power supply 18 of the high-voltage power electronics 8.

[0043] Fig. Figure 3a shows a schematic representation of the division of a second embodiment of a power electronics unit 1 according to the invention. In this embodiment, the power electronics unit 1 has an electrically conductive housing 3. In the illustrated embodiment, the boundary 4 comprises an electrically conductive shielding plate, which is formed at right angles. By means of the boundary 4, the electrically conductive housing 3 is divided into an interference sink area 5 and an interference source area 6.

[0044] In an alternative embodiment, the areas of the disturbance sink area 5 and the disturbance source area 6 are interchanged.

[0045] Fig.Figure 3b shows a schematic representation of the division of a third embodiment of a power electronics unit 1 according to the invention. In this embodiment, the power electronics unit 1 has an electrically conductive housing 3 and a partition 4 with an electrically conductive shielding plate. By means of the shielding plate, which is U-shaped, the electrically conductive housing 3 is divided into an interference sink area 5 and an interference source area 6.

[0046] In an alternative embodiment, the areas of the disturbance sink area 5 and the disturbance source area 6 are interchanged.

[0047] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as examples and not as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to a person skilled in the art when using the present invention and upon a detailed analysis of the drawings, the disclosure, and the subsequent claims.

[0048] In the claims, the words "comprise" and "with" do not preclude the presence of further elements or steps. The undefined article "a" or "an" does not preclude the presence of multiple elements. A single element or unit can perform the functions of several of the units mentioned in the claims. The mere mention of some measures in several different dependent claims is not to be understood as precluding the advantageous use of a combination of these measures. Reference numerals in the claims are not to be understood as limiting. Reference sign 1 power electronics unit 2 vehicles 3 cases 4. Demarcation 5 disturbance sink area 6 Interference source area 7. Higher-level vehicle system 8 High-voltage power electronics 9 printed circuit board 10 Low-voltage connection 11 Low-voltage signals 12 Battery connection 13 Power supply for the power electronics unit 14 Mass area 15 decoupling capacitor 16 filter elements 17 Commutation cell 18 Power supply for the high-voltage power electronics 19 busbars 20 cables 21 Battery QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 2020 14 101 689 U1

[0005]

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