Current sensor arrangement for a power inverter

Abstract

The present invention relates to a current sensor arrangement for a power inverter, comprising a current sensor and a flexible element for electrically connecting a power module to an AC busbar (3), wherein the flexible element has a through-opening that is closed on the circumferential side, wherein the current sensor is arranged in the through-opening such that it is electrically isolated from the flexible element.

Description

[0001] R.414792

[0002] Description

[0003] title

[0004] State of the art

[0005] The present invention relates to a current sensor arrangement for a power inverter.

[0006] Power inverters are an essential component in electric vehicles. For efficient operation, reliable measurement of electrical currents, especially on the AC side, is necessary. This requires high vibration resistance from the power inverter, combined with a small installation space and low manufacturing costs.

[0007] Disclosure of the invention

[0008] The current sensor arrangement according to the invention, comprising the features of claim 1, and the power inverter with the current sensor arrangement comprising the features of claim 13, have the advantage that the current sensor can be reliably, cost-effectively, and space-savingly arranged on a current-carrying flex element of the power inverter in order to determine an electric current through the flex element. This is achieved according to the invention by the current sensor arrangement comprising a current sensor and a flex element for the electrical connection of a power module to an AC busbar. The flex element has a circumferentially closed through-opening, wherein the current sensor is arranged in the through-opening in an electrically insulated manner from the flex element. The flex element can preferably compensate for small relative movements between the power module and the busbar that may occur during operation. The AC busbar preferably connects the R.414792

[0009] - 2 -

[0010] The power module is electrically connected to one phase of the electric motor. Its arrangement within the through-hole allows for a compact and reliable current sensor assembly. The current sensor is preferably positioned perpendicular to the flexible element to minimize the required through-hole size.

[0011] The dependent claims describe preferred embodiments of the invention.

[0012] Preferably, the current sensor arrangement comprises a printed circuit board (PCB) to which the current sensor is electrically connected. The PCB is arranged, in particular, parallel to the flexible element. A control unit for the power module can be arranged on the PCB. Thus, the measured values ​​of the current sensor can be used directly for controlling the power module.

[0013] The current sensor preferably has an electrically insulating plastic casing. This plastic casing can be manufactured, for example, using an injection molding process. The plastic casing allows for simple and cost-effective implementation of reliable insulation between the current sensor and the flexible element. The plastic casing preferably completely encloses the current sensor, except for a short section of the connecting pins for electrical contact.

[0014] Preferably, a housing component is arranged between the current sensor and the through-hole to electrically isolate the current sensor. This housing component can, for example, be part of the sheathing of the AC busbar. This allows the use of a standard current sensor, which can be easily and reliably electrically isolated from the flexible element by means of the housing component. The housing component is preferably arranged without contact with the current sensor.

[0015] The current sensor preferably comprises connecting legs, the distal ends of which are arranged at a 180° angle to each other for contact with the printed circuit board. The current sensor is preferably arranged in an opening in the printed circuit board, with the connecting legs supporting the sensor. The connecting legs, arranged at a 180° angle to each other, allow the current sensor to easily and reliably contact the printed circuit board. R.414792

[0016] - 3 -

[0017] The connecting legs have at least one bend to allow them to spread apart. This preferably results in the connecting legs being arranged in a V-shape relative to each other. This allows the current sensor to be reliably and vibration-resistant mounted, for example, on a circuit board.

[0018] The through-hole is preferably arranged centrally on a longitudinal axis of the flexible element. In particular, the flexible element is preferably symmetrical to its longitudinal axis. This allows for a uniform current flow with low inductance, which enables fast switching of the power module and low heating of the flexible element.

[0019] A longitudinal plane of the current sensor is preferably arranged parallel to the current flow direction at the through-hole. This allows the through-hole to be made as narrow as possible in the current flow direction, thereby reducing the electrical resistance of the flexible element.

[0020] Preferably, the current sensor is arranged to float in an opening in the circuit board. This increases the vibration resistance of the current sensor, as vibrations are not transmitted directly from the circuit board to the current sensor.

[0021] The flexible element is preferably a stamped and bent component made from a copper sheet. This allows the flexible element to be manufactured simply and cost-effectively while maintaining very good electrical properties.

[0022] The through-opening is preferably rectangular and extends in particular along a longitudinal axis of the flexible element. This allows for a constant distance to a flat current sensor while maintaining ease of manufacture. The corners of the rectangular shape may be rounded.

[0023] The current sensor is preferably a Hall sensor, in particular a gradient Hall sensor. This sensor technology enables reliable, non-contact measurement of the electrical current flow in the flexible element. R.414792

[0024] - 4 -

[0025] Furthermore, the invention relates to a power inverter comprising a current sensor arrangement as previously described. Using this current sensor arrangement, a compact and vibration-resistant power inverter can be provided, which, by means of the current sensor, can reliably measure the electrical current flow in the flexible element between the power module and the AC busbar, thus enabling reliable control of the power inverter.

[0026] Brief description of the drawings

[0027] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings. The drawing shows:

[0028] Figure 1 shows a perspective view of a power inverter with a

[0029] Current sensor arrangement according to a first embodiment of the invention and

[0030] Figure 2 shows a perspective view of a power inverter with a

[0031] Current sensor arrangement according to a second embodiment of the invention.

[0032] Embodiments of the invention

[0033] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0034] The following section describes in detail a power inverter 100 with a current sensor arrangement 1, with reference to Figures 1 and 2.

[0035] Figure 1 shows a section of the power inverter 100 in which the current sensor arrangement 1 is located. The current sensor arrangement 1 comprises a current sensor 10 and a flexible element 20. The flexible element 20 has a circumferentially closed through-hole in which the current sensor 10 is electrically insulated. The flexible element 20 connects a phase terminal of the power module 2 to an AC busbar 3. The connection between the flexible element 20 and the power module 2, as well as the AC busbar 3, is preferably made by soldering, welding, or sintering.

[0036] - 5 - designed to enable the transmission of high electrical currents at low electrical resistance.

[0037] The Flexelement 20 is a stamped and bent component made from a flat copper sheet.

[0038] The through-opening 21 is arranged centrally on a longitudinal axis XX of the flexible element 20. The flexible element 20 is symmetrical about the longitudinal axis XX. The through-opening 21 is rectangular and extends along the longitudinal axis XX.

[0039] The current sensor 10 has a planar, cuboid geometry, with a longitudinal plane of the current sensor 10 arranged parallel to a current flow direction at the through-opening 21 and perpendicular to the surface of the flexible element 20. The distance between the flexible element 20 and the current sensor 10 is essentially constant due to the geometry of the through-opening 21.

[0040] The current sensor 10 has an electrically insulating plastic casing. The current sensor 10 has four short connecting legs 13 that protrude from the plastic casing 11 at a distal end of the current sensor 10 and are arranged at a 180° angle α to each other. The connecting legs 13 preferably have a length between 2 mm and 3 mm.

[0041] The current sensor 10 is suspended in an opening 31 in the circuit board 30. The connecting pins 13 contact the circuit board 30 on the side facing away from the flexible element 20. Simultaneously, the connecting pins 13 enable electrical contact with the circuit board 30.

[0042] The current sensor 10 is designed as a gradient Hall sensor and can determine the electric current through the flex element 20 without contact.

[0043] Figure 2 shows a second embodiment of the current sensor arrangement 1. The second embodiment differs essentially in the geometry of the current sensor 10 and its insulation from the flexible element 20. R.414792

[0044] - 6 -

[0045] The current sensor assembly 1 has a housing component 12 that circumferentially encloses the current sensor 10 in the gap to the flexible element 20 in order to electrically isolate the current sensor 10 from the flexible element 20. The housing component 12 is made of a plastic and has further functions. For example, the housing component 12 also secures the AC busbar 3 and electrically isolates it from other components, such as the circuit board 30.

[0046] The recess of the housing component 12, on which the current sensor 10 is arranged, has an opening to the circuit board 30. The circuit board 30 is electrically contacted by the current sensor 10 on a side facing the current sensor 10 via connecting legs 13. The connecting legs 13 each have two bends 14 to spread apart from each other. Two connecting legs 13 of the current sensor 10 are bent to one side, and two other connecting legs 13 of the current sensor 10 are bent to the opposite side. Overall, the connecting legs 13 are each bent by 90°, so that the distal ends of the connecting legs 13 are arranged at a 180° angle to each other.

[0047] The insulating housing component 12 in the through-opening 21 allows a standard gradient Hall sensor to be used as a current sensor 10 without requiring an additional electrically insulating plastic sheath 11. The electrical insulation of the current sensor 10 from the flexible element 20 enables the current sensor 10 to be positioned in a relatively small through-opening 21. This allows the current sensor 10 to be arranged in the through-opening 21 of the flexible element 20 in a space-saving manner, without significantly affecting the electrical properties of the flexible element 20 and enabling a reliable determination of the electric current in the flexible element 20.

Claims

R.414792 - 7 - Claims 1. Current sensor arrangement for a power inverter, comprising a current sensor (10) and a flex element (20) for electrically connecting a power module (2) to an AC busbar (3), wherein the flex element (20) has a circumferentially closed through-opening (21), wherein the current sensor (10) is electrically insulated from the flex element (20) in the through-opening (21).

2. Current sensor arrangement according to claim 1, comprising a printed circuit board (30), wherein the current sensor (10) is electrically connected to the printed circuit board (30).

3. Current sensor arrangement according to one of the preceding claims, wherein the current sensor (10) has an electrically insulating plastic casing (11).

4. Current sensor arrangement according to one of the preceding claims, wherein a housing component (12) is arranged between the current sensor (10) and the through-opening (21) to electrically insulate the current sensor (10).

5. Current sensor arrangement according to one of claims 2 to 4, wherein the current sensor (10) comprises connecting legs (13), wherein distal ends of the connecting legs (13) are arranged at a 180° angle (a) to each other in order to contact the circuit board (30).

6. Current sensor arrangement according to one of the preceding claims, wherein the connecting legs (13) have at least one bend (14) to spread apart from each other. R.414792 - 8 - 7. Current sensor arrangement according to one of the preceding claims, wherein the through-opening (21) is arranged centrally on a longitudinal axis (XX) of the flex element (20).

8. Current sensor arrangement according to one of the preceding claims, wherein a longitudinal extent plane of the current sensor (10) is arranged parallel to a current flow direction at the through-opening (21).

9. Current sensor arrangement according to one of claims 2 to 8, wherein the current sensor (10) is arranged floating in an opening (31) in the circuit board (30).

10. Current sensor arrangement according to one of the preceding claims, wherein the flexible element (20) is a stamped and bent component made of a copper sheet.

11. Current sensor arrangement according to one of the preceding claims, wherein the through-opening (21) is rectangular and extends in particular along a longitudinal axis (XX) of the flex element (20).

12. Current sensor arrangement according to one of the preceding claims, wherein the current sensor (10) is a Hall sensor, in particular a gradient Hall sensor.

13. Power inverter comprising a current sensor arrangement (1) according to any one of the preceding claims.

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