Power module, inverter with power module and electric drive with inverter

Abstract

The present invention relates to a power module (10) for an electric axle drive (22) for an electric vehicle or a hybrid vehicle, the power module comprising: a plurality of semiconductor switching elements (107, 108a-c, 109) disposed on a substrate, the plurality of semiconductor switching elements being correspondingly mounted on the substrate; and a control device connected to the semiconductor switching elements for controlling the semiconductor switching elements (107, 108a-c, 109), wherein the semiconductor switching elements include a first semiconductor switching element (108a-c) for energizing the electric axle drive (22), and wherein the semiconductor switching elements additionally include a second semiconductor switching element (107, 109) for a transmission (20) connected to the electric axle drive (22).

Description

Technical Field

[0001] The present invention relates to a power module for an inverter of an electric drive for an electric vehicle or a hybrid vehicle, a corresponding inverter, and a corresponding electric drive. Background Technology

[0002] Pure electric vehicles and hybrid vehicles are known in the prior art. Pure electric vehicles are driven solely by one or more electric motors as drive components. In hybrid vehicles, one or more electric motors are used to assist the combustion engine. To supply electrical energy to the electric motors of such electric or hybrid vehicles, electric and hybrid vehicles include energy storage devices, particularly rechargeable batteries (e.g., lithium-ion batteries or hydrogen-based fuel cells). These batteries are designed as DC voltage sources; however, the electric motors generally require AC voltages with multiple (typically three) current phases. This generates a rotating electromagnetic field in the electric motor, which induces the rotor of the electric motor to rotate.

[0003] Therefore, power electronics with so-called inverters are typically connected between the battery and motor in electric or hybrid vehicles. These inverters usually include semiconductor switching elements, which are typically composed of transistors. Advantageously, semiconductor switching elements with varying degrees of integration are provided: either as discrete, standalone switches with low integration but high scalability, or as power modules with high integration but low scalability, and as half-bridges that fall between standalone switches and half-bridges in terms of integration and scalability.

[0004] In certain structural forms of electric machines, shift transmissions, such as two-stage shift transmissions, are provided to achieve targeted speed ratios. These shift transmissions are particularly used in high-power electric and hybrid vehicles to achieve higher speeds with relatively lower machine speeds, thus providing more energy-efficient and effective power transmission. Additional power electronics are required to operate the shift transmission, which in turn manipulate one or more shift elements.

[0005] Electric machines equipped with gear shifters, as known from the prior art, suffer from the following drawbacks: the power electronics used to operate the electric machine and the power electronics used to operate the gear shifter require costly manufacturing processes. Furthermore, in known electric machines, the large number of electronic components limits the feasibility of achieving a compact structure. Additionally, adequate sealing of the structural space used for the semiconductor switching elements within the corresponding power electronics is not adequately ensured. Summary of the Invention

[0006] The object of the present invention is to provide an inverter for an electric drive in an electric vehicle or a hybrid vehicle that improves upon the aforementioned disadvantages.

[0007] According to the invention, this objective is achieved by a power module, inverter, and electric driver having the features of the invention. Advantageous designs and improvements of the invention are derived from preferred embodiments.

[0008] In one aspect, the present invention relates to a power module for an electric drive for an electric vehicle or a hybrid vehicle.

[0009] The power module includes: a plurality of semiconductor switching elements correspondingly arranged on a substrate, and a control device for controlling the semiconductor switching elements.

[0010] The substrate can be designed as, for example, a DBC (Direct Bonded Copper) substrate, an AMB (Active Metal Brazing) substrate, or an IM (Insulated Metal) substrate. Semiconductor switching elements (especially transistors and diodes) are arranged on the substrate. Alternatively, multiple substrates with semiconductor switching elements distributed thereon can be provided. The substrate is preferably designed as rectangular, especially as a flat, disk-shaped rectangle having two opposite side edges. Alternatively, the substrate can be designed as square.

[0011] Semiconductor switching elements form a half-bridge, preferably at least three half-bridges, which are respectively assigned to the current phases of the multiphase output current. Each half-bridge includes a high side and a low side. The high side includes one or more semiconductor switching elements connected in parallel with each other, which are subjected to a relatively high potential during half-bridge operation. The low side includes one or more semiconductor switching elements connected in parallel with each other, which are subjected to a relatively low potential during half-bridge operation. The high side and the low side are connected in series with each other.

[0012] Preferably, the semiconductor switching element is designed as a bipolar transistor with an insulated gate electrode, and / or as a silicon carbide-metal-oxide-semiconductor-field-effect transistor. Bipolar transistors with insulated gate electrodes are also commonly known herein as so-called IGBTs. Silicon carbide-metal-oxide-semiconductor-field-effect transistors are also commonly known herein as so-called SiC-MOSFETs. These types of semiconductor switching elements are relatively well-suited for low-loss and fast switching, even at higher currents.

[0013] It is particularly preferred that each bipolar transistor with an insulated gate electrode is assigned a freewheeling diode. The freewheeling diode protects its corresponding assigned bipolar transistor with an insulated gate electrode from inductive overvoltages, especially when switching transistors.

[0014] A control device is used to switch semiconductor switching elements, and this control device has signal terminals electrically connected to the semiconductor switching elements. Depending on the design of the semiconductor switching elements, the semiconductor switching elements can be switched by conducting or blocking current by energizing or applying a voltage to them. Preferably, the semiconductor switching elements are switched in this way according to pulse-width modulation (PWM) to achieve a sinusoidal time curve of the phase current.

[0015] According to the invention, the semiconductor switching element includes a first semiconductor switching element for energizing the electric drive, and the semiconductor switching element additionally includes a second semiconductor switching element for a transmission connected to the electric axle drive. Preferably, the second semiconductor switching element is designed to energize an electric motor that generates pressure in a fluid line through which a transmission cooling medium or transmission lubricating medium flows, thereby enabling the operation of the transmission and / or a pump. This enables a power module in which not only are semiconductor switching elements arranged to convert direct current on the input side into multiphase alternating current on the output side by a targeted switching process, wherein the phase current is introduced into the windings of the electric axle drive of the electric vehicle or hybrid vehicle, but more specifically, semiconductor switching elements are also arranged in the same power module that similarly convert direct current into alternating current, wherein the phase current of the alternating current is introduced into the windings of at least one electric motor of the transmission connected to the electric axle drive. In this way, a unique power module is required for the electric axle drive of the electric vehicle or hybrid vehicle and the transmission (especially a shift transmission) connected to the axle drive. This enables the use of combined or shared power electronics for electric axle drives and transmissions, which are advantageous in terms of manufacturing simplicity and saving structural space.

[0016] According to one embodiment, the control device has a shared circuit board on which the first semiconductor switching element and the second semiconductor switching element are arranged. In this way, only a single circuit board is needed to house the first and second semiconductor switching elements, thereby simplifying the manufacturing of the power module.

[0017] Preferably, the first semiconductor switching element and the second semiconductor switching element are arranged facing the same side of the shared circuit board. This simplifies manufacturing by assembling the circuit board on one side. Alternatively, the first semiconductor switching element is applied to a cooling body, more preferably located below the circuit board (applied to the side of the circuit board facing away from the housing), while the second semiconductor switching element is applied to the side of the circuit board facing the housing.

[0018] Further preferably, a shared processing unit for controlling the first and second semiconductor switching elements is arranged on a shared circuit board. This measure enables a power module in which only a single processing unit is needed to control the semiconductor switching elements, both for the actual electric axle driver and for the transmission connected to that electric axle driver. By eliminating the need for a separate processing unit, significant cost savings are achieved, and a compact power module structure is realized. Another advantage of the shared processing unit is the higher software processing speed. In particular, the shared processing unit operates significantly faster than two processors operating in master-slave configuration.

[0019] According to another embodiment, the power module includes a first power terminal for electrically contacting the first semiconductor switching element and a second power terminal for electrically contacting the second semiconductor switching element, wherein the first power terminal is designed to apply a first input current, and wherein the second power terminal is designed to apply a second input current, wherein the first power terminal and the second power terminal are current-isolated. The first input current is, for example, a direct current generated by a DC power source (e.g., a battery) for an electric axle drive. Depending on the vehicle power, the input voltage can be as high as 400V or 800V, resulting in a correspondingly high first input current. The second input current is, for example, a direct current associated with a typical 12V mains voltage vehicle power supply network. Due to the significant difference in input voltage and thus the resulting significant difference in input current, it is advantageous for safety to use power terminals that are current-isolated from each other to electrically contact the different semiconductor switching elements.

[0020] In another aspect, the present invention relates to an inverter for an electric drive for an electric vehicle or a hybrid vehicle, the inverter comprising a power module according to the invention.

[0021] According to one embodiment, the inverter includes a housing with a shared cavity designed within it for the first semiconductor switching element, the second semiconductor switching element, and the control device. Thus, the first and second semiconductor switching elements are arranged within the shared cavity. This enables shared power electronics for the actual electric axle drive and the transmission connected thereto, advantageously reducing the space requirements for the power electronics compared to known products that have separate structural spaces for the respective power electronics.

[0022] The inverter preferably includes a common cooling element disposed within the housing, the cooling element being thermally coupled to the first and second semiconductor switching elements. In this way, a single cooling element is required for both the actual electric axle drive and the transmission connected to it. It is preferable to dissipate heat from the semiconductor switching elements via the housing. It is preferable to dissipate heat from the semiconductor switching elements via the cooling element. By eliminating the need for a separate cooling element, the resulting power module is particularly compact, thereby reducing the manufacturing cost of the inverter.

[0023] According to another embodiment, the housing has multiple fastening holes, preferably screw holes, for securing the inverter to the electric drive and / or transmission. In this way, the inverter's housing can be used as a cover for the electric axle drive or transmission. This facilitates a unified structural form for the overall assembly of the inverter and the electric axle drive and / or transmission. This further saves structural space.

[0024] Preferably, the housing has a cover portion and a base portion that can be closed by the cover portion, wherein at least one of the fastening holes is designed as a through hole extending from the top side of the cover portion through a structural space inside the housing to the bottom side of the base portion. In this way, by closing the cover portion onto the base portion, the entire housing (e.g., as a cover) can be simultaneously fastened to the electric axle drive and / or transmission. Therefore, the inverter can be reliably mounted on the electric axle drive and / or transmission. Attached Figure Description

[0025] The invention will now be described by way of example with reference to the embodiments shown in the accompanying drawings.

[0026] In the attached diagram:

[0027] Figure 1 The possible structure of the power module of the present invention for an electric drive of an electric vehicle or hybrid vehicle is illustrated exemplary and schematically.

[0028] Figure 2An exemplary and schematic exploded view is shown of a possible inverter according to one implementation.

[0029] Figure 3 Exemplary and schematic cross-sectional view shown Figure 2 The inverter section; and

[0030] Figure 4 Exemplary and schematic cross-sectional view shown Figure 2 Another section of the inverter. Detailed Implementation

[0031] Identical objects, functional units, and similar components are denoted by the same reference numerals throughout the drawings. These objects, functional units, and similar components are implemented identically in terms of their technical features, unless otherwise expressly or implicitly derived from the specification.

[0032] Figure 1 The possible structure of a power module 10 for an electric axle drive 22 of an electric vehicle or hybrid vehicle according to the present invention is schematically shown. The power module 10 includes a housing 12, within which a structural space is designed. Power electronics 14 are arranged within the structural space. The power electronics 14 are shown herein in a highly simplified manner and generally include a plurality of semiconductor switching elements, which are correspondingly mounted on a substrate. The substrate is arranged on a circuit board, on which control devices for operating the various semiconductor switching elements are also mounted. The semiconductor switching elements include a first semiconductor switching element for the electric axle drive 22 of the electric vehicle or hybrid vehicle. Furthermore, the semiconductor switching elements also include a transmission 20 for connection to the electric axle drive, enabling the electric axle drive to switch between at least two gear levels.

[0033] like Figure 1 As shown in a highly simplified and schematic manner, the transmission 20 includes a transmission housing 18, inside which a transmission control device 16 is arranged. The transmission control device 16 can be controlled accordingly by means of a second semiconductor switching element from the power electronics 14 (particularly by targeted switching of the second semiconductor switching element) to operate the transmission 20.

[0034] Therefore, in Figure 1 The diagram shows a common power electronics 14 for the actual electric axle drive 22 and the transmission 20 connected thereto. The structural space in which the common power electronics 14 are arranged is a dry structural space, which is isolated from other structural spaces (especially the structural spaces in the transmission 20 or the electric axle drive 22) in order to protect the semiconductor switching elements.

[0035] In addition, Figure 1 The diagram also shows, in a highly simplified and purely schematic manner, signal terminals 17 for controlling the valves of the transmission and / or for detecting shift signals of the transmission. These signal terminals 17 are preferably applied to the circuit board 104 and extend into the oil structure space of the transmission control unit 16. The signal terminals 17 are preferably oil-sealed using a plastic material (especially a thermosetting material). This eliminates the need for signal lines extending outside the power module housing, thereby reducing manufacturing costs. Simultaneously, the oil seal ensures high reliability of signal guidance.

[0036] Figure 2 An exploded view schematically illustrates a possible inverter 100 according to one embodiment. The inverter 100 includes a housing having a cover portion 102 and a base portion 116. The base portion 116 is closable by means of screw-fit connections to the cover portion 102, with a plurality of through holes 124, 126, 128, 130, 132, 134 for these screw-fit connections. A seal is provided at the connection point between the cover portion 102 and the base portion 116 for sealing against environmental influences (e.g., oil particles intruding from the outside). The entire housing, in its closed state (where the base portion 116 is closed by means of screw-fit connections to the cover portion 102), can thus be closed at the housing of the electric axle drive 22 and / or the transmission 20. Figure 4 More details are shown and described in detail below.

[0037] The inverter 100 also includes a power core 105. The power core 105 specifically includes a cooling element 110 through which a cooling medium (e.g., water) flows. For this purpose, multiple cooling pipes are designed inside the cooling element 110. A cooling medium inlet 118 and a cooling medium outlet 120, fluidly connected to two associated openings 117 and 119 of the cooling element 110, are arranged at the base portion 116.

[0038] The inverter 100 also includes a control device with a circuit board 104. A plurality of first semiconductor switching elements 108a, 108b, and 108c are arranged on the side of the power core 105 facing the circuit board 104. These first semiconductor switching elements are configured to operate the electric bridge driver 22. A plurality of insertion openings are designed on the side of the circuit board 104 facing the power core 105, into which a plurality of contact elements arranged above the first semiconductor switching elements 108a, 108b, and 108c can be inserted to secure the first semiconductor switching elements 108a, 108b, and 108c to the circuit board 104. The first semiconductor switching elements 108a-c are respectively exemplarily mounted on a substrate (e.g., direct copper plating, DBC), which is in turn mounted on a coolant 110, thereby forming thermal coupling between the first semiconductor switching elements 108a-c and the coolant 110. The first semiconductor switching element is preferably divided into three groups: the first group of 108a semiconductor switching elements is used to generate the first phase current of the multiphase output current (AC current), the second group of 108b semiconductor switching elements is used to generate the second phase current of the multiphase output current, and the third group of 108b semiconductor switching elements is used to generate the third phase current of the multiphase output current.

[0039] Meanwhile, a plurality of second semiconductor switching elements 107, 109 are mounted on the side of circuit board 104 facing the power core 105. The second semiconductor switching elements 107, 109 are configured for use with a transmission 20 connected to an electric axle drive 22 and, exemplarily, include a first group 107 for operating the transmission (particularly for operating shift elements of the transmission 20) and a second group 109 for use with an oil pump designed to cool the transmission 20. The first group 107 and the second group 109 are respectively connected to associated electric machines (particularly associated electric motors) to operate the switching elements or operate the oil pump by energizing the respective electric machines. Therefore, a common circuit board 104 is referred to here, on which not only the first semiconductor switching elements 108a-c are mounted, but also the second semiconductor switching elements 107, 109 are mounted.

[0040] On the side facing the cover portion 102, the circuit board 104 is equipped with a plurality of electronic components, which exemplarily include a plurality of driver components electrically connected to the first semiconductor switching elements and the second semiconductor switching elements 108a-c, 107, 109, and a plurality of intermediate circuit capacitors, which respectively form the commutation circuit of a corresponding half-bridge composed of semiconductor switching elements. A processing unit 106 is also mounted on the circuit board 104, which is electrically connected to the first semiconductor switching elements 108a-c and the second semiconductor switching elements 107, 109 via driver components. Therefore, this relates to a shared processing unit 106, which is used to control the first semiconductor switching elements 108a-c and thus the bridge driver 22 of an electric or hybrid vehicle, and to control the second semiconductor switching elements 107, 109 and thus the transmission 20.

[0041] Multiple power terminals 112a-c, 114 are arranged on the power core 105, allowing them to be secured to contact positions provided for this purpose in the base portion 116. The power terminals 112a-c, 114 include two DC-side power terminals 114, each comprising a positive DC power terminal for contacting the positive terminal of the DC input terminal 122 of the inverter 100, and a negative DC power terminal for contacting the negative terminal of the DC input terminal 122 of the inverter. Furthermore, multiple (three in this example) AC-side power terminals 112a-c are arranged on the power core 105 for outputting a corresponding phase current of the multiphase output current (alternating current) to the electric bridge driver 22. In this example, the AC-side power terminals 112a-c are arranged on the ends of the power core 105 opposite to the DC-side power terminals 114.

[0042] Figure 3 Schematic diagram shown in cross-sectional view Figure 2 The section of inverter 100 is shown in particular. A hermetically sealed fastener is shown for bus 136, which is electrically connected to one of the AC-side power terminals 112a-c to output the associated phase current to the windings of the electric bridge driver 22. The hermetically sealed fastener is formed by two first sealing rings 142, 144, which are arranged between the head of bus 136 and an insulation regulator 146 for electrically insulating bus 136. The insulation regulator 146 is then laterally sealed relative to the base portion 116 of the housing by means of a second sealing ring 138. The second sealing ring 138 is, for example, a multi-lip seal that engages radially and preferably form-fitted into the housing. The inner wall of the housing is preferably designed smoothly in the area of ​​the engagement.

[0043] like Figure 3As also shown, the cooling medium inlet 118 and cooling medium outlet 120 are sealed relative to the housing by means of a radial seal 146 and simultaneously sealed relative to the cooling body 110 by means of an axial seal 148. In the radial seal 146, the sealing surface extends circumferentially. In the axial seal 148, the surface normal of the sealing surface points in the axial direction. This measure ensures that the cooling medium guide is sealed to prevent contamination from inside the power module and from the structural space of the electric motor and transmission (e.g., due to the liquid lubricant of the transmission).

[0044] Figure 4 Schematic diagram shown in cross-sectional view Figure 2 Another section of the inverter 100 is shown. Specifically, through-holes are shown in the screw-fit connections between the housings 102, 116 of the inverter 100 and the housing 200 of the electric axle drive 22 and / or transmission 20. The through-holes include: a first section consisting of pairs of through-holes 132, 126 (or 134 and 124); and a second section 202 formed in the housing 200 of the electric axle drive 22 and / or transmission 20 and oriented coaxially with the first section. The paired through-holes 132 and 126 (or 134 and 124) are also two coaxially oriented through-holes (through-holes). In this way, the entire housing 102, 116 of the inverter 100 can be closed in the closed state (where the base portion 116 is closed by means of a screw-on connector with the cover portion 102) and thus at the housing 200 of the electric axle drive 22 and / or the transmission 20.

[0045] List of reference numerals

[0046] 10 Power Modules

[0047] 12. Shell

[0048] 14 Power Electronic Devices

[0049] 16. Transmission control unit

[0050] 18. Shell

[0051] 20 Transmission

[0052] 22 Electric Axle Drive

[0053] 100 inverter

[0054] 102 Cover plate section

[0055] 104 circuit board

[0056] 105 power core

[0057] 106 processing units

[0058] 107 First group of second semiconductor switching elements

[0059] 108a-c First Semiconductor Switching Element

[0060] 109 Second group, second semiconductor switching element

[0061] 110 cooling body

[0062] 112a-c AC side power terminals

[0063] 114 DC side power terminals

[0064] 116 Matrix Part

[0065] 118 Cooling medium inlet

[0066] 120 Cooling medium outlet

[0067] 122 DC input terminal

[0068] 124, 126, 128, 130, 132, 134 through openings

[0069] 136 bus

[0070] 138 Second sealing ring

[0071] 142, 144 First sealing ring

[0072] 200 housing

[0073] 202 Through opening

Claims

1. A power module (10) for an electric axle drive (22) in an electric vehicle or hybrid vehicle, the power module comprising: A plurality of semiconductor switching elements (107, 108a-c, 109) are arranged on a substrate, and the plurality of semiconductor switching elements are respectively mounted on the substrate; and a control device, which is connected to the semiconductor switching elements (107, 108a-c, 109) for controlling the semiconductor switching elements. The semiconductor switching element includes a first semiconductor switching element (108a-c) for energizing the electric bridge driver (22). The semiconductor switching element additionally includes a second semiconductor switching element (107, 109) for connection to the transmission (20) of the electric axle drive (22). The control device has a common circuit board (104) on which the first semiconductor switching element (108a-c) and the second semiconductor switching element (107, 109) are arranged. The first semiconductor switching element is located on one side below the circuit board, while the second semiconductor switching element is applied on the side of the circuit board different from the first semiconductor switching element.

2. The power module (10) according to claim 1, wherein a common processing unit (106) for controlling the first semiconductor switching element (108a-c) and the second semiconductor switching element (107, 109) is arranged on a common circuit board (104).

3. The power module (10) according to claim 1 or 2, further comprising: A first power terminal (114) for electrically contacting the first semiconductor switching element (108a-c) and a second power terminal for electrically contacting the second semiconductor switching element (107, 109), wherein the first power terminal (114) is designed to apply a first input current, wherein the second power terminal is designed to apply a second input current lower than the first input current, wherein the first power terminal (114) is current-isolated from the second power terminal.

4. The power module (10) according to claim 1 or 2, wherein the second semiconductor switching element (107, 109) is designed to energize an electric motor that thereby manipulates the transmission (20) and / or operates a pump to generate pressure in a fluid line through which the transmission cooling medium or transmission lubricating medium flows.

5. The power module (10) according to claim 1 or 2, wherein a signal terminal (17) is provided on the circuit board (104) to control the valves of the transmission and / or to detect the shift signal of the transmission, the signal terminal extending into the oil structure space of the transmission control device (16), wherein the signal terminal (17) is oil-sealed.

6. The power module (10) according to claim 5, wherein the signal terminal (17) is oil-sealed with a plastic material.

7. The power module (10) according to claim 5, wherein the signal terminal (17) is oil-sealed with a thermosetting material.

8. An inverter (100) for an electric axle drive (22) for an electric vehicle or a hybrid vehicle, the inverter comprising a power module (10) according to any one of claims 1 to 7.

9. The inverter (100) according to claim 8, the inverter further comprising a housing having a shared cavity in which the first semiconductor switching element (108a-c), the second semiconductor switching element (107, 109) and the control device are designed.

10. The inverter (100) according to claim 9, further comprising a cooling element (110) disposed in the housing, the cooling element being thermally coupled to the first semiconductor switching element (108a-c), wherein the second semiconductor switching element (107, 109) is thermally coupled to the housing and is thereby heat-dissipating.

11. The inverter (100) according to claim 10, wherein the cooling body (110) is part of the housing, such that the first semiconductor switching element (108a-c) is also heat-dissipating through the housing.

12. The inverter (100) according to claim 9, the inverter further comprising a common cooling body (110) disposed in the housing, the common cooling body being thermally coupled to the first semiconductor switching element (108a-c) and the second semiconductor switching element (107, 109).

13. The inverter (100) according to any one of claims 8 to 12, wherein the housing has a plurality of fastening holes (124, 126, 128, 130, 132, 134) for securing the inverter (100) to the electric axle drive (22) and / or the transmission (20).

14. The inverter (100) according to any one of claims 8 to 12, wherein the housing has a plurality of screw holes for securing the inverter (100) to the electric axle drive (22) and / or the transmission (20).

15. The inverter (100) of claim 13, wherein the housing has a cover portion (102) and a base portion (116) that can be closed by the cover portion (102), wherein at least one of the fastening holes (124, 126, 128, 130, 132, 134) is designed as a through hole extending from the top side of the cover portion (102) through a structural space inside the housing to the bottom side of the base portion (116).

16. The inverter (100) according to any one of claims 8 to 12, wherein the cooling medium inlet (118) and / or the cooling medium outlet (120) are sealed relative to the housing by means of a radial seal (146) and relative to the cooling body (110) by means of an axial seal (148).

17. An electric bridge driver (22) comprising an inverter according to any one of claims 8 to 16.

18. The electric bridge driver (22) according to claim 17, wherein the electric bridge driver is an electric motor.

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