Liquid-cooled power electronics unit

Abstract

Liquid-cooled power electronics unit (10) with a plate-shaped circuit board body (20) having conductor tracks (22), wherein the power electronics unit (10) has a wet side (W) with a wet space (30) carrying a dielectric cooling liquid (100) and a fluidically separated dry side (D), wherein at least two high-voltage power semiconductors (40, 40') are arranged on the board body (20) on the wet side (W) within the wet space (30), and wherein an electronic low-voltage circuit (50) is arranged on the dry side (D) of the circuit board body (20), characterized in that the high-voltage power semiconductors (40, 40') arranged on the wet side (W) within the wet space (30) are cooled by the cooling liquid (100), wherein a heat sink (80, 82) is applied to the distal sides of the high-voltage power semiconductors (40, 40').

Description

[0001] The invention relates to a liquid-cooled power electronics unit with multiple high-voltage power semiconductors and with an electronic low-voltage circuit for controlling the high-voltage power semiconductors. In particular, the invention relates to a power electronics unit of a motor vehicle with an electric traction drive, for example, to a power electronics unit of an inverter or converter for charging the traction battery or for engine operation.

[0002] Such power electronics units have to meet high requirements regarding cooling and galvanic isolation of the high-voltage power semiconductors and a low-voltage circuit for controlling the power semiconductors.

[0003] DE 10 2007 050 417 A1 discloses a liquid cooling system for high-voltage power semiconductors. However, in such an arrangement, the low-voltage circuit would have to be provided as a separate unit.

[0004] US 2018 / 0 199 465 A1 discloses a liquid-cooled power electronics unit according to the preamble of claim 1.

[0005] DE 10 2008 035 228 A1 and JP 2002 - 325 467 A disclose further prior art.

[0006] The object of the invention is to create a compact liquid-cooled power electronics unit with an integrated low-voltage electronic circuit that is galvanically isolated from the power semiconductors.

[0007] This object is achieved according to the invention by a liquid-cooled power electronics unit having the features of claim 1 and having the features of claim 4.

[0008] The liquid-cooled power electronics unit according to claim 1 and claim 4 has a plate-shaped circuit board body having conductor tracks, wherein a wet side, on which a dielectric cooling liquid flows, and a dry side are fluidically separated from one another. On the wet side, the power electronics unit forms a wet space through which the dielectric cooling liquid flows, wherein all high-voltage power semiconductors or the entire high-voltage circuit are or are arranged on the wet side of the circuit board body or in the wet space. The high-voltage power semiconductors are electrically connected to one another by conductor tracks applied to the circuit board body. All high-voltage power semiconductors are preferably arranged in a single wet space. The electronic low-voltage circuit, on the other hand, is arranged on the dry side of the circuit board body and is therefore fluidically insulated and separated from the wet side or the dry side.from the high-voltage power unit.

[0009] A low-voltage circuit is understood here to be a circuit that has electrical voltages of a maximum of 60 V. The high-voltage circuit operates with electrical voltages of more than 60 V, in particular with electrical voltages of several hundred V up to over 1000 V. The low-voltage circuit and the high-voltage circuit are therefore galvanically isolated from one another according to claim 4, wherein this separation is identical to the fluidic separation. Since the low-voltage circuit controls the high-voltage power semiconductors, according to claim 4 there is at least one electrically isolating signal connection between the low-voltage circuit and the high-voltage power semiconductors for transmitting the control signals from the low-voltage circuit to the high-voltage power semiconductors. The electrically isolating signal connection can be optical, capacitive and / or inductive.

[0010] In principle, the high-voltage power semiconductors and / or the high-voltage power section on the one hand and the low-voltage circuit on the other hand can be arranged next to each other on the same side of the plate-shaped circuit board body, wherein the fluidic separation between the high-voltage power section and the low-voltage circuit is formed by a fluid-tight partition wall placed on the circuit board body.

[0011] Furthermore, according to claim 4, a sensor for determining a physical parameter of the dielectric cooling fluid is arranged on the wet side of the circuit board body. This sensor is informationally connected to the low-voltage circuit via the potential-isolating signal connection. The sensor determines, for example, the temperature of the cooling fluid, its degree of contamination, its conductivity, and / or its flow velocity.

[0012] According to claim 1, a heat sink is applied to the distal side of each high-voltage power semiconductor or multiple high-voltage power semiconductors, which improves heat spreading and correspondingly increases the effective heat exchange surface. The heat sink can be a metal heat sink, but can also consist of a plastic potting material enclosing the respective power semiconductor. The heat sink can have fins or needles to increase the surface area.

[0013] However, it is particularly preferred that the plate-shaped circuit board itself separate the wet space from the dry space, so that the high-voltage power section with the high-voltage power semiconductors is arranged on one base surface of the circuit board body, and the low-voltage circuit is arranged on the opposite base surface of the circuit board body. This allows for a very compact design of the entire power electronics unit.

[0014] Preferably, a metal plate is integrated into the plastic circuit board body, extending over most of the base area of ​​the circuit board body and parallel to both base areas of the circuit board body. The metal plate is cast into the circuit board body in an electrically insulated manner. The metal plate serves, on the one hand, to improve heat distribution and heat spreading, and, on the other hand, in particular, to mechanically stabilize the circuit board body, which may be exposed to a certain excess pressure from the dielectric coolant on its wet side. The metal plate is preferably a thick copper plate.

[0015] An exemplary embodiment of the invention is explained in more detail below with reference to the drawing. The figure shows a schematic longitudinal section of a liquid-cooled power electronics unit with a plate-shaped circuit board body that fluidically and electrically separates the wet side with a dielectric cooling liquid from the dry side, on which a low-voltage electronic circuit is arranged.

[0016] The figure schematically shows a liquid-cooled power electronics unit 10, which forms, for example, a converter in a motor vehicle with an electric traction drive. The power electronics unit 10 has a plate-shaped circuit board body 20, which is equipped with several electronic components on both sides. The circuit board body 20 fluidically and galvanically separates a wet side W and a dry side D from each other. On the wet side W, the power electronics unit 10 forms a fluidically closed wet space 30, in which a dielectric cooling liquid 100 flows between a cooling liquid inlet 35 and a cooling liquid outlet 36 of the wet space 30.

[0017] On the wet side W of the circuit board body 20, several high-voltage power semiconductors 40, 40' are arranged within the wet space 30 on the circuit board body 20 and are directly electrically connected to other electronic components via conductor tracks 22 arranged on the wet side W of the circuit board body 20. The operating voltage of the high-voltage power semiconductors 40, 40' is several hundred volts, for example, 400 volts or 800 volts.

[0018] Each power semiconductor 40, 40' has a heat sink 80, 82, which spreads heat and increases the heat-exchanging surface. One heat sink 80 is a metal heat sink provided with a plurality of distally projecting cooling fins and thermally coupled, for example, glued, to the respective power semiconductor 40. The other heat sink 82 is formed by a plastic encapsulation body 84, which seals the respective power semiconductor 40' in a fluid-tight manner, since the latter is sensitive to liquids. The encapsulation body heat sink 82 also forms distally projecting cooling fins.

[0019] On the dry side D, which in this case forms an open drying chamber 32, which can alternatively also be closed, an electronic low-voltage circuit 50 is provided, which is operated with a maximum working voltage of 60 V. The low-voltage circuit 50 controls, regulates, and monitors the high-voltage circuit 42 formed by the high-voltage power semiconductors 40, 40'. In particular, the high-voltage power semiconductors 40, 40' are controlled by the low-voltage circuit 50.

[0020] The plate-shaped circuit board body 20 is formed by an electrically non-conductive plastic base body 22, in which a copper metal plate 24 is embedded approximately centrally, parallel to the two base surfaces, which plate mechanically stabilizes the circuit board body 20, in particular with respect to normal forces, and which furthermore causes a large-area heat spreading of the heat generated in the power semiconductors 40, 40'.

[0021] The high-voltage power semiconductors 40, 40' are informationally connected to the low-voltage circuit 50 via a potential-isolating signal connection 60. Furthermore, a wet-room-side sensor 70 for determining several physical parameters of the coolant 100 is bidirectionally informationally connected to the low-voltage circuit 50 via the aforementioned signal connection. The sensor 70 determines, among other things, the temperature, electrical conductivity, and flow rate of the coolant 100.

[0022] The signal connection 60 is formed by an inductive transceiver element 62 on the wet side W and a corresponding inductive transceiver element 61 on the dry side D. The circuit board body metal plate 24 has an opening 25 in this area, which allows inductive transmission through the circuit board body 20 in this area.

[0023] The low-voltage circuit 50 is electrically connected to a vehicle-side control unit via a connector 90.

Claims

[1] Liquid-cooled power electronics unit (10) with a plate-shaped circuit board body (20) having conductor tracks (22), wherein the power electronics unit (10) has a wet side (W) with a wet space (30) carrying a dielectric cooling liquid (100) and a fluidically separated dry side (D), wherein at least two high-voltage power semiconductors (40, 40') are arranged on the board body (20) on the wet side (W) within the wet space (30), and wherein an electronic low-voltage circuit (50) is arranged on the dry side (D) of the circuit board body (20), characterized by , that the high-voltage power semiconductors (40, 40') arranged on the wet side (W) within the wet space (30) are cooled by the cooling liquid (100), wherein a heat sink (80, 82) is applied to the distal sides of the high-voltage power semiconductors (40, 40'). [2] Liquid-cooled power electronics unit (10) according to claim 1, wherein the low-voltage circuit (50) and the high-voltage power semiconductors (40, 40') are galvanically isolated from one another and a potential-isolating signal connection (60) exists between the low-voltage circuit (50) and the high-voltage power semiconductors (40, 40'). [3] Liquid-cooled power electronics unit (10) according to claim 1 or 2, wherein a sensor (70) for determining a physical quantity of the cooling liquid (100) is arranged on the wet side (W) of the circuit board body (20), which sensor is informationally connected to the low-voltage circuit (50). [4] Liquid-cooled power electronics unit (10) with a plate-shaped circuit board body (20) having conductor tracks (22), wherein the power electronics unit (10) has a wet side (W) with a wet space (30) carrying a dielectric cooling liquid (100) and a fluidically separated dry side (D), wherein on the wet side (W) within the wet space (30) at least two high-voltage power semiconductors (40, 40') are arranged on the board body (20), which are cooled by the cooling liquid (100), and wherein an electronic low-voltage circuit (50) is arranged on the dry side (D) of the circuit board body (20), characterized by , that the high-voltage power semiconductors (40, 40') arranged on the wet side (W) within the wet space (30) are cooled by the cooling liquid (100), the low-voltage circuit (50) and the high-voltage power semiconductors (40, 40') are galvanically separated from each other and a potential-isolating signal connection (60) exists between the low-voltage circuit (50) and the high-voltage power semiconductors (40, 40'), on the wet side (W) of the circuit board body (20) a sensor (70) for determining a physical quantity of the cooling liquid (100) is arranged, which sensor is informationally connected to the low-voltage circuit (50) via the potential-isolating signal connection (60). [5] Liquid-cooled power electronics unit (10) according to claim 4, wherein a heat sink (80, 82) is applied to the distal sides of the high-voltage power semiconductors (40, 40'). [6] Liquid-cooled power electronics unit (10) according to one of claims 1 to 5, wherein the circuit board body (20) fluidically separates the wet space (30) and the dry space (32) from each other. [7] Liquid-cooled power electronics unit (10) according to one of the preceding claims, wherein a metal plate (24) is integrated into the plastic circuit board body (20).

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