Power converter, electrical machine unit, use of a component and method for manufacturing a power converter

Abstract

The invention relates to a power converter (120) for use with an electric machine (110) having a rotor (112), a stator (116) and a fan (118), wherein the power converter (120) is designed to be attached to the electric machine (110), wherein the power converter (120) has a component (130) which has a predetermined breaking point (150) which is designed to create an opening in the component (130) for the gas to flow to the electric machine (110) when there is an overpressure of gas in the power converter.

Description

[0001] The present invention relates to a power converter for use with an electrical machine, an electrical machine unit with an electrical machine and a power converter, a use of a component in such a power converter and a method for producing a power converter. Background of the invention

[0002] In electrical machines, especially those used in vehicles, so-called inverters (power converters) are used to rectify generated alternating current or to convert applied direct current and thus enable operation of the electrical machine. Disclosure of the invention

[0003] According to the invention, a power converter, an electrical machine unit, a use of a component, and a method for producing a power converter are proposed, having the features of the independent patent claims. Advantageous embodiments are the subject of the dependent claims and the following description.

[0004] The invention relates to electrical machines and associated power converters or inverters. The combination of electrical machine and associated power converter shall be referred to as an electrical machine unit within the scope of the invention. Typically, the power converter is attached or mounted to one end of the electrical machine. The electrical machine comprises a rotor, a stator, and a fan. The fan can be fastened or attached, in particular, to the rotor or a rotor shaft, in particular connected thereto in a rotationally fixed manner. A typical position for such a fan is on the side of the power converter so that it—like the electrical machine itself—can be efficiently cooled.

[0005] For this purpose, the power converter can, in particular, have ventilation openings and cooling fins on a heat sink, so that air can be drawn from outside the power converter or the electrical machine unit into the interior of the power converter by means of the fan. The air can then be directed past or along the cooling fins, in particular, to cool the heat sink and the electronics of the power converter arranged on it. It is also possible, however, to allow air to flow in the opposite direction, so that the air flows from the interior to the outside through the ventilation openings.

[0006] The electric machine unit can be part of a vehicle, in particular, it can also be used as a traction drive. Examples of electric machines that can be considered include synchronous machines, synchronous reluctance machines, induction machines, permanent magnet machines, and others. Such an electric machine unit can also be used as a so-called boost recuperation machine (or generally as a starter generator), typically in conjunction with an internal combustion engine.

[0007] If problems arise during operation of the electrical machine or the power converter, e.g., if the power converter is overloaded or malfunctions, high pressures of air or other gas can develop inside the power converter. This can cause a cover (shroud) that is, for example, firmly attached or sealed to the heat sink or another part of the inverter and / or a protective cap of the power converter to be lifted, and hot gas can escape through the ventilation openings (provided, for example, in the protective cap) and pose a hazard (thermal incident) to components in the vicinity of the electrical machine unit, for example, in the engine compartment of the vehicle.

[0008] Against this background, it is now proposed that a component, e.g., a housing component, of the power converter have a predetermined breaking point, i.e., that such a component be deliberately provided with a predetermined breaking point. The predetermined breaking point is designed to create an opening in the component for the gas to flow to the electric machine in the event of excess gas pressure in the power converter. Although the term "predetermined breaking point" is used here, it can also refer to a larger area that is deliberately designed to be weaker, i.e., a predetermined breaking area.

[0009] This prevents damage to or endangerment of components outside the power converter, such as the vehicle. Instead, any excess pressure and hot gas can be released in a controlled manner into the interior of the electrical machine unit or into the electrical machine.

[0010] One idea in particular is to move the outlet area for the overpressure from the edge of the protective cap, where the ventilation openings are located, to an inner area, in particular on the opposite side of the power converter.

[0011] In one embodiment, the component is formed or manufactured from plastic, at least in the area of ​​the predetermined breaking point. This facilitates the introduction of the predetermined breaking point and its effectiveness.

[0012] In one embodiment, the component is designed as a sensor mount or is used as such. A rotor position sensor and / or a temperature sensor can then be arranged in this sensor mount. The component can therefore be a component of the power converter that forms an interface between the electronic components on a circuit board inside the power converter and the aforementioned sensors, which are arranged near the rotor.

[0013] Another advantage is that no additional parts are required. Replacing the sensor mount with one with a predetermined breaking point, or adding the predetermined breaking point, does not significantly increase the cost of the parts.

[0014] The rotor position sensor and the temperature sensor are sensors for two important measured variables during the operation of such an electrical machine unit. The rotor position angle can be important, for example, for controlling the electrical machine. The rotor position sensor (or rotor angle indicator) can be used for this purpose. Such a rotor position sensor typically works inductively, i.e. a magnetic field generated by the rotor and its orientation with respect to a rotational axis of the rotor is detected. This can be used to determine or measure the current rotor position. For this purpose, the rotor position sensor is typically arranged on the rotational axis or at least substantially on the rotational axis of the rotor. For example, the rotor position sensor can be arranged at a suitable location on the power converter.

[0015] The temperature of the electrical machine or electrical machine unit is important in that the electrical machine or power converter should not overheat. A particularly suitable position for measuring the temperature is, if possible, near the fan. This allows the temperature of an airflow between the electrical machine and the power converter to be determined, which is a good indicator of the temperature of the electrical machine or electrical machine unit.

[0016] As has been shown, it can be complex to properly position and install a rotor position sensor and a temperature sensor. In particular, this often requires many individual and diverse components.

[0017] The aforementioned sensor mount now allows for a particularly clever arrangement of the rotor position sensor and temperature sensor. By also incorporating the predetermined breaking point, the usefulness of this sensor mount can be further increased.

[0018] The sensor mount comprises a first sensor housing part and a second sensor housing part. The first sensor housing part is configured to accommodate the rotor position sensor, and the second sensor housing part is configured to accommodate the temperature sensor.

[0019] When using the sensor holder with an electrical machine unit, the sensor holder can then in particular be or will be arranged in or on the electrical machine unit in such a way that the rotor position sensor can be or is or will be arranged in the first sensor housing part in such a way that the rotor position sensor lies at least substantially (i.e., e.g., as precisely as possible) on the axis of rotation of the rotor. This can also be done in such a way that the temperature sensor can be or is or will be arranged in the second sensor housing part in such a way that the temperature sensor is less than a predetermined distance, e.g., less than 10 mm, less than 5 mm, or less than 4 mm, from the fan.

[0020] In one embodiment, the first sensor housing part has a cylindrical recess into which the rotor position sensor can be inserted. This allows for very simple, quick, and precise positioning of the rotor position sensor such that it lies on the rotation axis and also close to the rotor shaft. The predetermined breaking point can then particularly preferably be arranged or provided in a wall of this cylindrical recess.

[0021] As mentioned, the invention also relates to an electrical machine unit with a power converter having the aforementioned component, a use of a component in a power converter, and a method for producing a power converter. Regarding the advantages and embodiments, reference is made to the above statements, which apply here accordingly.

[0022] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0023] The invention is illustrated schematically in the drawing using exemplary embodiments and is described below with reference to the drawing. Short description of the drawings Fig. 1 schematically shows an electrical machine unit according to the invention in a preferred embodiment. Fig. 2 shows schematically a part of the electrical machine unit of Fig. 1 in a different view. Fig. 3 shows schematically a part of the electrical machine unit of Fig. 1 in a different view. Embodiment(s) of the invention

[0024] In Fig. Figure 1 shows a rough schematic of an electrical machine unit 100 according to the invention in a preferred embodiment. The electrical machine unit 100 has an electrical machine 110 and a power converter or inverter 120. The electrical machine 110, in turn, has a rotor 112, a stator 116, and a fan 118. The rotor 112 has a rotor shaft 114 with a rotation axis R, by means of which the rotor 112 is rotatably or rotatably mounted in a bearing not shown in detail. The fan 118 is arranged or attached to the rotor shaft 114 in a rotationally fixed manner, for example.

[0025] The power converter 120 is arranged or attached to the electric machine 110 at one axial end of the electric machine 110. The fan 118 is arranged on the side of the power converter 120, so that an air flow generated by the fan 118 can cool not only the electric machine 110 (or the rotor 112 and the stator 116 of the electric machine), but also the power converter or electrical components of the power converter, e.g., via a heat sink 125 present in or on the power converter. A (possibly additional) fan could also be arranged at the other axial end of the electric machine.

[0026] The heat sink 125 and cooling fins 124 arranged thereon are in Fig. 1 only hinted at, a more detailed view of this can be found in Fig. 3. In addition, Fig. 1 however, ventilation openings 126 which are provided on the circumference of the power converter 120, e.g. in its protective cap 122, and serve for air exchange from outside to inside and / or inside to outside.

[0027] Furthermore, the power converter 120 comprises electrical and / or electronic parts and components, or generally an electronics system 128. These electrical and / or electronic parts and components are covered or protected by a cover 123. The cover 123 can, for example, be firmly screwed to the heat sink and, in particular, also form an enclosed space in which the electronics system 128 is located.

[0028] Furthermore, the power converter 120 or the electric machine unit 100 has a component 130 designed as a sensor mount. The sensor mount 130 is arranged between an axial end of the rotor shaft 114 (on the side of the fan 118) and the power converter 120 (possibly in a recess in the power converter 120). For example, the sensor mount 130 can be fastened in the power converter 120 using suitable fastening means.

[0029] The sensor holder 130 has a predetermined breaking point 150 which is designed to create an opening in the sensor holder 130 for the gas to the electric machine 110 in the event of an overpressure of gas in the power converter 120, in particular in the area of ​​the electronics 128.

[0030] A more detailed description of the sensor holder 130 as well as the sensors incorporated or capable of being incorporated therein, rotor position sensor and temperature sensor, will be given below with reference to the other figures.

[0031] In Fig. 2 is a schematic view of a part of the electrical machine unit of Fig. 1 is shown in a different view. In particular, the sensor mount 130 is shown as an example and in a more detailed view, as well as the rotor shaft 114 with the fan 118 attached to it.

[0032] The sensor mount 130 has a first sensor housing part 132 and a second sensor housing part 136, both of which can be formed integrally with one another. For example, the sensor mount 130 can be made of plastic; in particular, the sensor mount can be manufactured by injection molding.

[0033] The first sensor housing part 132, in turn, has a cylindrical recess 134. For this purpose, the first sensor housing part 132 can, for example, be shaped accordingly. The cylindrical recess 134 has an axis or axis of symmetry R1. A rotor position sensor 140 is introduced into the cylindrical recess 134 and thus in the first sensor housing part 132, and in particular is also fixed there. The sensor holder 130 and the second sensor housing part 132 are arranged and aligned (e.g. in or on the power converter, not shown here) such that the rotor position sensor 140 lies at least substantially on the axis of rotation R of the rotor 112. This is achieved, for example, by the axis R1 coinciding with the axis of rotation R. The rotor position sensor 140 can thus detect or measure the rotor position angle.

[0034] The second sensor housing part 136 has an elongated, e.g., cylindrical, sleeve 138. For this purpose, the second sensor housing part 136 can, for example, be shaped accordingly. The sleeve 138 has an axis or axis of symmetry or extension R2. The axis R2 forms, for example, an angle a with the axis R1 that is greater than zero, e.g., 5°. The second sensor housing part 136 or the sleeve 138 has a length (along the axis R2) such that one end of the sleeve 138, which is on the side of the fan 118, is very close to the fan 118, e.g., at a distance of approximately d from the fan 118. The sleeve 138 can be closed at this end, on the side of the fan 118, but open at the other end. A temperature sensor 142 can thus be introduced into the sleeve 138 and thus into the second sensor housing part 136, in particular, for example, up to the stop at the closed end.This allows the temperature sensor 142 to be brought very close to the fan 118, for example, to a distance of d. Depending on the wind force of the sleeve at the closed end and the specific mounting of the sensor holder 130 in the electrical machine unit 100, a length of the sleeve 138 along the axis R2 can be selected such that the temperature sensor 142 is located at a distance d from the fan 118.

[0035] The predetermined breaking point 150 is provided in the first sensor housing part 132, and there in particular in a wall 133 of the cylindrical recess 134. The wall 133 is here in particular perpendicular to the axis R1, which corresponds to the rotational axis R of the rotor. Furthermore, the wall 133 is here in particular arranged at least substantially symmetrically to the axis R1 or R. The predetermined breaking point 150 lies in particular on the axis R1 or R.

[0036] In Fig. 3 is a schematic view of a part of the electrical machine unit of Fig. 1 in a different view, namely the power converter 120 or a part thereof and the sensor holder 130. The rotor position sensor and the temperature sensor are not shown here, but the temperature sensor can be incorporated into the second sensor part or the sleeve.

[0037] Of the power converter 120, the heat sink 125 and the cooling fins 124 arranged thereon can be seen here in particular. The sensor holder 130 is arranged in a central recess in the heat sink 125. In the event of overpressure in an area or space between the heat sink and the cover (in Fig. 1, where the electronics are located), the material of the sensor holder 130 breaks in the area of ​​the predetermined breaking point 150, and this creates an opening towards the electrical machine.

[0038] The predetermined breaking point 150 can be designed in different ways depending on the requirements, e.g. as an individual, thinner material area in the wall, which can be added directly during production (e.g. using the injection molding process) or subsequently. The shape of the predetermined breaking point 150 can also be designed according to requirements, e.g. as a circle with a cross in it as shown here. Just a cross would also be conceivable, for example. Both the material thickness and the shape of the predetermined breaking point 150 can influence the pressure required for the predetermined breaking point 150 to break and thus create the opening. It is expedient if the predetermined breaking point 150 is designed in such a way that in the event of excess pressure, the predetermined breaking point 150 breaks first and not the aforementioned cover is lifted.

Claims

[1] Power converter (120) for use with an electrical machine (110) having a rotor (112), a stator (116) and a fan (118), wherein the power converter (120) is configured to be attached to the electrical machine (110), wherein the power converter (120) has a component (130) having a predetermined breaking point (150) which is configured to create an opening in the component (130) for the gas to the electrical machine (110) in the event of an overpressure of gas in the power converter. [2] Power converter (120) according to claim 1, wherein the component (130) is arranged in a region of the power converter which is to be arranged on a rotation axis (R) of the rotor. [3] The power converter (120) of claim 1 or 2, comprising ventilation openings (126), wherein the ventilation openings are arranged on an outer periphery of the power converter. [4] Power converter (120) according to one of the preceding claims, wherein the component (130) is formed from plastic at least in the region of the predetermined breaking point (150). [5] Power converter (120) according to one of the preceding claims, which has a rotor position sensor (140) and / or a temperature sensor (142) for measuring a temperature of the electrical machine (110), in particular in the vicinity of the fan, wherein the component (130) is designed as a sensor holder, and wherein the rotor position sensor (140) and / or the temperature sensor (142) are arranged in the component. [6] Power converter (120) according to claim 5, wherein the component (130) has a first sensor housing part (132) and a second sensor housing part (136), wherein the first sensor housing part (132) is adapted to receive the rotor position sensor (140), and wherein the second sensor housing part (136) is adapted to receive the temperature sensor (142). [7] Power converter (120) according to claim 6, wherein the first sensor housing part (132) has a cylindrical recess (134) into which the rotor position sensor (140) can be introduced, and wherein the predetermined breaking point is arranged in a wall (133) of the cylindrical recess. [8] Electric machine unit (100), wherein the electric machine unit comprises an electric machine (110) with a rotor (112), a stator (116) and a fan (118), and a power converter (120) according to one of the preceding claims, [9] Use of a component (130) in a power converter (120) of an electrical machine (110) having a rotor (112), a stator (116) and a fan (118), wherein the power converter (120) is attached or is to be attached to the electrical machine (110), wherein the component (130) has a predetermined breaking point (150) which is designed to create an opening in the housing component for the gas in the event of an overpressure of gas in the power converter. [10] Method for producing a power converter (120) for use with an electrical machine (110) having a rotor (112), a stator (116) and a fan (118), wherein the power converter (120) is designed to be attached to the electrical machine (110), wherein a component (130) is introduced into the power converter (120), which component is provided with a predetermined breaking point (150) and which is designed to create an opening in the component for the gas in the event of an overpressure of gas in the power converter.

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