An electrical device having one or more sensors at a power conducting element and / or a power switching element that is fluidically circulated

Abstract

The invention relates to an electrical device (100) comprising a first housing (102) having a wet space (104) and a dry space (106) separated from one another by a wall (108), fluid-filled or through-flown. One or more power-conducting elements (120) and / or power-switching elements (122) are arranged in the wet space (104), electronic control means (124) for the power-switching elements (122) being arranged in the dry space (106). The wall (108) comprises an opening (110), a second housing (130) extending to the power-conducting elements (120) or surrounding the power-conducting elements (120) extending from the opening into the wet space (104). A sensor (132) measuring a variable related to the electrical power flowing through the power-conducting elements (120) is arranged in the second housing (130). The second housing (130) fluid-tightly closes the opening (110) in the wall (108). A line (134) transmitting the measured values or measurement signals of the sensor (132) passes through the opening (110) in the wall (108) into the dry space (108).

Description

Technical Field

[0001] The present invention relates to an electrical device, such as an electrical device for a motor vehicle, and more particularly to a measuring device for power electronic devices, such as those used to control an electric drive device, that are circulated / surrounded by fluid. Background Technology

[0002] It is not uncommon for vehicle drive motors to have power in the three-digit kW range. This power must be supplied to the drive motor in a suitable manner; in particular, the power must be supplied ideally and continuously, or at least in steps / spans as small as possible, between minimum and maximum values.

[0003] The power supplied to the drive motor is provided by the corresponding control circuit, for example, to set the desired speed and / or desired torque. Many vehicles use self-excited or separately excited synchronous or asynchronous motors, i.e., motors configured to operate on alternating current (AC). However, the energy storage units in electric or hybrid vehicles are almost always electrochemical energy storage units that provide DC voltage. Therefore, the control circuit typically includes an inverter that converts the DC voltage into AC voltage with the frequency required for the desired speed and the amplitude required for the demanded power.

[0004] To convert DC voltage to AC voltage, semiconductor switches rapidly and continuously switch between on and off states. During these switching operations, energy is lost as heat each time, and this heat needs to be properly dissipated to safely prevent the temperature from rising above the maximum permissible operating temperature of the semiconductor switch. Because high current always flows at high power levels, the wiring must be sized accordingly. Buses, which are rigid conductors made of copper or aluminum with a sufficiently large cross-section, are frequently used in control circuits. These buses also dissipate some of the heat loss generated during semiconductor switching operation.

[0005] To achieve effective cooling in confined spaces, power electronic devices are typically housed in enclosures filled with or flowing through non-conductive fluids. Oil, in particular, is used here, having been employed for decades in power system transformers for cooling purposes.

[0006] Because the coolant also flows at least partially around the power conduction components, sensors used to measure values ​​related to electrical power, such as current sensors and temperature sensors, located at the power conduction or power switching elements, are sealed to prevent direct contact with the coolant. However, even when using resin-cast sensors, due to the different materials and their varying properties, it is not always reliable to prevent coolant from penetrating into the sensor's interior. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide an electrical device having one or more sensors at a power transmission element or power switching element surrounded by fluid, the electrical device reliably preventing the one or more sensors from coming into contact with the fluid.

[0008] This objective is achieved by the electrical equipment specified in claim 1. Claim 7 specifies a method for assembling the electrical equipment. Advantageous configurations and further improvements are described in the dependent claims.

[0009] The electrical device according to the invention has a first housing comprising a wet space and a dry space, which are filled or flow through a fluid. The wet space and the dry space are separated from each other by a wall. The fluid is non-conductive. One or more power conducting and / or power switching elements are arranged in the wet space. Electronic controls for the power switching elements are arranged in the dry space. According to the invention, the wall includes an opening from which a second housing extends into the wet space. The second housing extends to or surrounds the power conducting element. A sensor is arranged in the second housing, configured to measure parameters related to the electrical power flowing through the power conducting element, such as current, temperature, or magnetic field flowing through one or more lines. The second housing fluid-tightly seals the opening in the wall. Lines transmitting the sensor's measurements or measurement signals pass through the opening in the wall into the dry space.

[0010] In one or more embodiments of the electrical device according to the invention, a seal is provided between a second housing and a wall. The seal may include a suitable resilient sealing device. The second housing may be connected to the wall such that the surface of the second housing abutting the sealing device pushes the sealing device against the wall, thereby creating a fluid seal. For example, the second housing may include an edge surrounding an opening in the wall and may be secured to the edge of the wall or opening by means of screws, clamps, snap-fit ​​connections, etc.

[0011] In one or more embodiments of the electrical device according to the invention, the second housing is open to the dry space in the region of the opening in the wall. In this case, the interior space of the second housing is in direct communication with the dry space, such that a line extending from the second housing can extend into the dry space through the opening in the wall.

[0012] However, the second housing can also be closed towards the dry space. In this case, the lines transmitting the sensor's measured values ​​or measurement signals can enter the dry space through the wiring guide or electrical plug connection in the outer wall of the second housing located above the opening.

[0013] Alternatively, the second housing may be filled with an electrically insulating varnish (Vergussmasse), and the lines transmitting the sensor's measurements or measurement signals may extend from the varnish through an opening in the wall of the first housing.

[0014] In one or more embodiments of the electrical device according to the invention, the second housing is configured to secure the power conducting element that the second housing reaches or surrounds in a wet space.

[0015] The electrical device according to the invention advantageously prevents the contacts of electrical sensors from being wetted by non-conductive fluids, thereby preventing measurement distortion or the measurement value from reaching the control circuit. Furthermore, flexible wiring is no longer required in the wet space, making the compatibility of the material with respect to the fluid irrelevant in terms of insulation, and eliminating the risk of fluid entering the dry space due to capillary effects within the insulation.

[0016] A method for assembling an electrical device according to the invention firstly includes providing a first housing, power conducting elements and power switching elements, electronic control devices, and a second housing in which sensors are arranged. The second housing is first arranged at or around at least one power conducting element, and then the at least one power conducting element is connected to at least one power switching element. The elements so connected can now be positioned in the wet space of the first housing. Alternatively, at least one power conducting element can be first connected to at least one power switching element, and then the second housing can be arranged at or around at least one power conducting element, positioning these elements in the wet space of the first housing. In another alternative, at least one power conducting element can be first connected to at least one power switching element, and then these elements can be positioned in the wet space of the first housing, finally arranging the second housing at or around at least one power conducting element. If the second housing is already arranged at or around the power conducting element when the elements are provided, the corresponding arrangement step is logically omitted.

[0017] The positioned components are now fixed in their proper places within the first housing, and the openings in the walls are fluid-tightly closed by means of the second housing. Electronic controls can now be placed in the dry space of the second housing and connected to lines transmitting sensor measurements or measurement signals. The electrical device according to the invention is particularly advantageously suited for electric or hybrid vehicles. Attached Figure Description

[0018] The invention will now be described by way of example with reference to the accompanying drawings. In the drawings:

[0019] Figure 1 A schematic diagram of an electrical device known in the prior art is shown, which has one or more sensors at the power transmission element.

[0020] Figure 2A schematic diagram of an electrical device known in the prior art is shown, which has one or more sensors at a power-conducting element surrounded by flowing fluid.

[0021] Figure 3 A schematic diagram of an electrical device according to the invention is shown, which has one or more sensors at a power-conducting element surrounded by fluid.

[0022] Figure 4 Showing from Figure 3 Details of the electrical device according to the invention, and

[0023] Figure 5 A flowchart of an exemplary method for assembling an electrical device according to the present invention is shown.

[0024] In the accompanying drawings, the same or similar elements may be represented by the same reference numerals. Detailed Implementation

[0025] Figure 1A schematic diagram of a prior art electrical device 100 is shown, which has one or more sensors 132 at a power conduction element 120. For example, the device forms a pulse inverter with a power module 122 including one or more power switching elements. The power module 122 is coupled to a cooling element 152 by means of a suitable thermal connection 150, which may be, for example, part of a housing 102 or a cooling element through which fluid flows. Here, the power conduction element 120 is a three-phase AC connector shown on the left side of the device 100, and a DC connector shown on the right side of the device. It should be noted that applications with fewer or more phases are also conceivable. For example, when the device is used to drive an asynchronous or synchronous motor (not shown) in an electric or hybrid vehicle, the AC connector constitutes the output of the device, while the DC connector draws energy from a battery (also not shown). In the vehicle's energy recovery operation, the energy flow is reversed, such that energy flows from the motor, which now operates as a generator, to the DC connector and ultimately into the battery. The conductors of the DC connector are provided with sensors 132 that measure the current flowing from the battery to the device. Sensor 132 is connected to electronic control unit 124 via line 134. Power module 122 is connected to DC connector via intermediate circuit capacitor 160. Power module 122 is controlled by electronic control unit 124 via control lines (not separately specified in the figure) to deliver appropriate three-phase AC current to AC connector. Current sensor 132 is provided to monitor functionality and enable precise control; this current sensor is shown here as a component for a combination of three-phase measurements. It should be noted that a separate sensor can also be used for each phase. This sensor is also connected to electronic control unit 124 via line 134. In this known electrical device, cooling of power module 122 can only be performed from one side, which may limit its maximum power.

[0026] Figure 2 A schematic diagram of a prior art electrical device 100 is shown, which has one or more sensors 132 at a power transmission element 120 surrounded by fluid. Here, the device also forms, for example, a pulse inverter having a power module 122 including one or more power switching elements. Here, the power transmission element 120 is also a three-phase AC connector shown on the left side of the device 100, and a DC connector shown on the right side. Also in this figure, for example, when the device is used to drive an asynchronous or synchronous motor (not shown) in an electric or hybrid vehicle, the AC connector constitutes the output of the device, while the DC connector draws energy from a battery (also not shown). Figure 1Compared to the electrical equipment shown, the housing 102 is divided into a wet space 104 and a dry space 106 by a wall 108. The power transmission element 120 and the power module 122 are arranged in the wet space 104, which is traversed by a cooling fluid, such as non-conductive oil. Therefore, the heat generated in the power module 122 and the power transmission element 120 can be more easily absorbed and released elsewhere.

[0027] The conductors of the DC connector are equipped with a sensor 132, which measures the current flowing from the battery to the electrical device and vice versa. The sensor 132 is connected to an electronic control unit 124 disposed in the dry space 106 via a line 134. The line 134 must pass through the wall 108, which requires an additional opening in the wall that must be fluid-tight, and the line must be connected to the sensor 132 in such a way that no cooling fluid can penetrate into the sensor 132, nor can it flow out of the wet space via the line 134.

[0028] Power module 122 is connected to the DC connector via intermediate circuit capacitor 160. Power module 122 is controlled by electronic controller 124 via control lines (not separately specified in the figure) to deliver appropriate three-phase AC current to the AC connector. A current sensor 132 is provided to monitor functionality and enable precise control; this current sensor is shown here as a component of the three-phase measurement assembly. (See reference...) Figure 1 As already noted, a separate sensor can also be used for each phase. This sensor is also connected to the electronic control unit 124 via line 134. Here, sensor 132 must also be protected from the ingress of cooling fluid, and the cooling fluid must not leak out from the wet space 104 along the insulation of the line. Achieving fluid tightness can be particularly difficult with flexible line 134.

[0029] Figure 3 A schematic diagram of an electrical device 100 according to the invention is shown, which has one or more sensors 132 at a power conducting element 120 surrounded by fluid. These elements and their respective functions, as well as their arrangement relative to each other, correspond to a reference. Figure 2 The description made. With Figure 2 Compared to the electrical device 100, here, the sensor 132 or its housing passes through an opening in the wall 108, such that the wiring from the sensor 132 to the electronic control device 134 is led out from the housing of the sensor 132 only in the dry space 106. Therefore, cooling fluid cannot come into contact with the wiring 134. The sensor housing extends upwards to or surrounds the power transmission element 120, but is designed to be completely fluid-tight relative to the wet space. Figure 4The invention is explained in more detail in the reference numeral D.

[0030] Figure 4 The electrical device 100 according to the present invention is shown to be from Figure 3 Detail D. In this figure, only wall 108 is visible from housing 102, which separates wet space 104 from dry space 106. An opening 110 is provided in the wall, through which sensor 132 is arranged in its housing 130 on the wet space side. Housing 130 completely covers opening 110 and seals wet space 104 relative to dry space 106 by means of seal 140. Housing 130 of sensor 132 can be secured, for example, by means of bolts 142. Power conduction element 120 passes through housing 130 of sensor 132. Here, housing 130 of sensor 132 is completely closed relative to wet space. Power conduction element 120 can also be secured to wall 108 through housing 130 of sensor 132. Sensor wiring 134 exits from sensor housing 130 in the area of ​​opening 110 and is located directly in dry space 106, such that no cooling fluid can penetrate into housing 130 of sensor 132 at the contact point.

[0031] Figure 5 A flowchart of an exemplary method 200 for assembling an electrical device 100 according to the invention is shown. In step 202, a first housing 102, a power conducting element 120 and a power switching element 122, an electronic control device 124, and a second housing 130 are provided, in which a sensor 132 is arranged. In step 204, the second housing 130 is arranged at or around at least one power conducting element 120. Then, in step 206, at least one power conducting element 120 is connected to at least one power switching element 122, and in step 208, the connected elements are positioned in the wet space 104 of the first housing 102 such that the second housing 130 is located in or above an opening 110 in the wall 108. Then, in step 210, at least one power conducting element 120 and the power switching element 122 are secured in the first housing. During or after this, in step 212, the opening 110 is fluid-sealed. In step 24, the electronic control device 124 is arranged in the dry space 106 of the first housing 102, and in step 216, the line 134 for transmitting the measured value or measurement signal of the sensor 132 is connected to the electronic control device 124.

[0032] List of reference numerals

[0033] 100 devices

[0034] 102 First Shell

[0035] 104 Wet Space

[0036] 106 Dry Space

[0037] 108 wall

[0038] 110 Opening

[0039] 120 power conduction element

[0040] 122 Power Switching Components / Power Modules

[0041] 124 Electronic control devices

[0042] 130 Second shell

[0043] 132 sensors

[0044] Route 134

[0045] 140 Seals

[0046] 142 screws

[0047] 150 heat bond

[0048] 152 Cooling Element

[0049] 160 Intermediate circuit capacitor

[0050] 200 methods

[0051] 202 provides

[0052] 204 Arrangement

[0053] 206 Connections

[0054] 208 Positioning

[0055] 210 Fixed

[0056] 212 Closed

[0057] 214 Arrangement

[0058] 216 Connections

Claims

1. An electrical device (100) having a first housing (102) having a wet space (104) filled or through which fluid flows and a dry space (106), the wet space and the dry space being separated from each other by a wall (108), wherein, One or more power conduction elements (120) and / or power switching elements (122) are arranged in the wet space (104), and wherein an electronic control device (124) for the power switching element (122) is arranged in the dry space (106), characterized in that the wall (108) includes an opening (110); a second housing (130) extends from the opening (110) into the wet space (104); the second housing (130) extends to or surrounds the power conduction element (120). A power conduction element (120); a sensor (132) is arranged in the second housing (130) and is configured to measure parameters related to the electrical power flowing through the power conduction element (120); the second housing (130) fluid-tightly closes the opening (110) in the wall (108); and a line (134) for transmitting the measured value or measurement signal of the sensor (132) passes through the opening (110) in the wall (108) into the dry space (106).

2. The electrical device (100) according to claim 1, wherein the seal (140) is disposed between the second housing (130) and the wall (108).

3. The electrical device (100) according to claim 1 or 2, wherein the second housing (130) is open toward the dry space (106) in the region of the opening (110) in the wall (108).

4. The electrical equipment (100) according to claim 1 or 2, wherein the second housing (130) is filled with an electrically insulating castable.

5. The electrical device (100) according to claim 1 or 2, wherein the second housing (130) is configured to extend into or surround the power conducting element (120) and secure it in the wet space (104).

6. The electrical device (100) according to claim 1 or 2, wherein the sensor (132) arranged in the second housing (130) is configured to measure current, temperature or magnetic field.

7. A method (200) for assembling an electrical device (100) according to any one of claims 1 to 6, the method comprising the steps of: a) Provides a first housing (102), a power conduction element (120) and a power switching element (122), an electronic control device (124) and a second housing (130), wherein a sensor (132) is arranged in the second housing. b) Arrange the second housing (130) at or around at least one of the power conducting elements (120), c) Connect at least one power conduction element (120) to at least one power switching element (122). d) Position at least one power conducting element (120) and a power switching element (122) in the wet space (104) of the first housing (102) such that the second housing (130) is located in or above the opening (110) in the wall (108). e) The at least one power conducting element (120) and the power switching element (122) are fixed in the first housing (102), and the opening (110) is fluid-tightly closed by the second housing (130). f) Arranging the electronic control device (124) in the dry space (106) of the first housing (102), and g) Connect the line (134) that transmits the measured value or measurement signal of the sensor (132) to the electronic control device (124).

8. The method (200) according to claim 7, wherein steps b), c) and d) are performed in alphabetical order or in the order of c), b), d) or in the order of c), d), b).

9. An electric or hybrid vehicle having electrical equipment (100) according to any one of claims 1 to 6.

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