Electronic circuit comprising a plurality of printed circuit boards connected by at least one busbar
The electronic circuit with foldable bus bars and layered printed circuits addresses the challenge of compact integration and disturbance reduction, enabling efficient high and low power management in turbomachines.
Patent Information
- Application Number
- FR2020003364
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2020-04-03
- Publication Date
- 2025-01-10
- Estimated Expiration
- 2040-04-03
AI Technical Summary
Existing electronic circuits for turbomachines face challenges in optimizing mechanical integration, managing high and low power signals, and reducing switching losses and inductance while maintaining compactness, due to significant filtering requirements that increase size and weight, and current solutions fail to completely eliminate disturbances.
An electronic circuit design featuring multiple printed circuits connected by foldable bus bars, with superimposed layers and buried bus bars, allowing high and low power networks on different layers, and forming a hemispherical envelope for compact integration around a circular electric motor.
The design achieves compact integration of power and signal management, reducing disturbances and maintaining performance by burying bus bars between layers, thus minimizing size and weight while effectively handling high and low power signals.
Smart Images
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Abstract
Description
Title of the invention: Electronic circuit comprising a plurality of printed circuits connected by at least one bus bar FIELD OF THE INVENTION
[0001] The present invention relates to the general field of electronic circuits and more particularly to the field of turbomachine electronic circuits. STATE OF THE ART
[0002] In the field of aircraft turbomachinery construction, equipment incorporating power electronics increasingly needs to be compact to be more easily integrated.
[0003] In particular, in the case of electronic circuits positioned against a circular electric motor of the turbomachine, it would be necessary to be able to optimize their mechanical integration. In addition, it would be necessary to bring the power control functions closer together to minimize switching losses and reduce inductance and therefore oversizing of the components.
[0004] Furthermore, within a turbomachine, the power electronics must be able to operate with high currents, which can go beyond 400 Arms to meet aircraft requirements.
[0005] However, the electronic circuits, positioned against a circular electric motor, must also manage low power signals.
[0006] However, current solutions combining power and small signals generate disturbances that are difficult to correct if the filtering between the power source and the power part is not well done.
[0007] This requires adding a filtering circuit whose size is proportional to the power of the motor and to the distance between the source of the disturbances and the circuit to be protected and this with a significant volume.
[0008] In the case of high power motors (greater than 50kW) this filtering can have a size and weight greater than the power part: that of the functions to be filtered
[0009] The disturbances generated are as follows:
[0010] - Self on the DC bus between the power switches
[0011] - Distortion and delay of power switch control signals
[0012] To reduce the impact of these phenomena, respectively it is known to add high energy capacities which harm the compactness of the system and add cost and / or functions for conditioning the control signals towards the power take up space and cost.
[0013] However, these provisions do not allow for the total elimination of disturbances. This also requires limiting the performance to be achieved.
[0014] In this context, the invention aims to provide an electronic circuit that can be placed against a circular electric motor, occupying a reduced volume, combining both weak signals and power electronics. Statement of the invention
[0015] According to a first aspect, the invention proposes an electronic circuit comprising a plurality of printed circuits connected by at least one bus bar, each printed circuit comprising at least two superimposed layers enclosing at least a portion of said at least one bus bar, so as to bury said at least one bus bar.
[0016] The electronic circuit may have inter-printed circuit spaces which only comprise said at least one bus bar.
[0017] Said at least one bus bar in each inter-circuit space may be bendable, so that two adjacent printed circuits are located in two intersecting planes.
[0018] Said at least one bus bar can be folded between two printed circuits so that the set of printed circuits define facets of a substantially hemispherical envelope.
[0019] At least one of the printed circuits may comprise at least two electrically separate bus bars.
[0020] Said at least two bus bars may have distinct electrical and / or mechanical properties.
[0021] At least one of the printed circuits may have a connector for connecting at least two elements among the two layers and at least one bus bar.
[0022] At least one of the printed circuits may have, on a first of its two layers, a high-power electronic network, and may have on a second of its two layers, a low-power electronic network.
[0023] According to another aspect, the invention relates to a method for manufacturing an electronic circuit of the invention, comprising the following steps: (a) positioning at least one bus bar on at least two first distinct layers of printed circuits, adjacent and separated by a space to connect them while maintaining an inter-circuit space in which there is only said at least one bus bar; (b) Stacking and laminating at least one second printed circuit layer over said at least one bus bar and a corresponding first layer, to bury said at least one bus bar between the two layers; (c) bending said at least one bus bar in each inter-circuit space.
[0024] Step (c) may comprise the following steps: (cl) bending said at least one bus bar in each inter-circuit space with a bending tool; (c2) Depositing an electrical insulator on said at least one bent bus bar in each inter-circuit area.
[0025] According to another aspect, the invention relates to a turbomachine comprising a circular electric motor having an external casing and an electronic circuit according to the invention, fixed against said casing.
[0026] According to another aspect, the invention relates to an aircraft comprising at least one turbomachine according to the invention. DESCRIPTION OF FIGURES
[0027] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:
[0028] [Fig. 1] [Fig. 1] is a perspective representation of an electronic circuit according to the invention positioned around a circular electric motor.
[0029] [Fig.2] [Fig.2] is a representation of an electronic circuit according to the invention before folding.
[0030] [Fig.3] [Fig.3] is a partial sectional representation of a printed circuit according to the invention.
[0031] [Fig.4] [Fig.4] is a representation of a bus bar.
[0032] [Fig.5] [Fig.5] is a representation of the positioning of the bus bar on a first layer of a printed circuit board.
[0033] [Fig.6] [Fig.6] is a representation of the bending of the bus bars between two circuits printed.
[0034] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION
[0035] General architecture
[0036] According to a first aspect, the invention proposes an electronic circuit 1 comprising a plurality of printed circuits 2 connected by at least one bus bar, each printed circuit comprising at least two superimposed layers enclosing at least a portion of said at least one bus bar 4, so as to bury said at least one bus bar 4.
[0037] Busbar
[0038] Busbars 4 are well-known elements in the field of electrical power distribution. Typically, a busbar 4 may be a metal strip (or bar) for distributing high currents. Most commonly, 4-bar busbars are made of solid metal such as copper. However, it is possible to use a metal alloy or a composite material consisting of a sandwich of different metals.
[0039] The dimensions of each bus bar 4 are defined according to the electric current which must flow there.
[0040] The busbar 4 according to the invention can be covered with an insulating resin.
[0041] In addition, each bus bar 4 may have branches and holes. holes 41 can receive a connector allowing the bus bar 4 to be electrically connected to another element.
[0042] Structure of a printed circuit
[0043] As previously indicated, each printed circuit comprises a plurality of layers.
[0044] Typically, the printed circuits 2 comprise at least three layers: two external layers 21 and at least one spacer layer 22.
[0045] The layers can be made of electrically insulating resin.
[0046] In a particularly advantageous manner, the outer layers 21 may be made of a rigid material, and the or each spacer layer 22 (inner layer) may be made of a softer material. Similarly, the layers may have different expansion coefficients.
[0047] Each outer layer may have conductive tracks and accommodate electronic components. In a known manner, the components may be inserted into holes. These holes are preferably made in conductive tracks to electrically connect the components, according to a chosen architecture. In addition, the electronic components may be soldered or brazed onto the outer layers.
[0048] One or more bus bars 4 may be buried in the spacer layer(s) 22.
[0049] As shown in the figures, the bus bars 4 can be juxtaposed or stacked. The spacer layer(s) 22 makes it possible to isolate the bus bars 4 from each other, and also to isolate them from the components of the external layers 21.
[0050] Thus, by traversing a printed circuit 2 from one external layer 21 to the other, it can have a first structured electronic network on a first external layer 21, then one or more bus bars 4 embedded in the spacer layer 22, and a second structured electronic network on the second external layer 21.
[0051] Of course, this architecture is only an example. It is thus possible to have only one electronic network on a single external layer 21, the other external layer 21 being left blank.
[0052] In addition, the printed circuit 2 may include connectors (also called vias) allowing an electrical connection to be made between several layers.
[0053] A connector can, for example, allow an electronic network of an external layer 21 to be electrically connected to a bus bar 4, or two external layers 21 to be electrically connected to a bus bar, or two superimposed bus bars 4 to be connected, etc.
[0054] In a particularly advantageous manner, the multilayer structure of the printed circuits 2, incorporating a spacer layer 22 in which bus bars 4 are buried, makes it possible in particular to have - for example - a high-power circuit on one external face and a low-power circuit on another external face. This also makes it possible to have high electrical powers circulating in the bus bars 4 and low powers in the electronic networks of the external faces. Thus, in summary, the structure according to the invention makes it possible to have high and low electrical power in the same printed circuit 2.
[0055] Connection between two printed circuits
[0056] As indicated previously, the electronic circuit 1 may comprise a plurality of printed circuits 2. The printed circuits 2 are physically linked and electrically connected by the bus bars 4.
[0057] More precisely, preferably, the printed circuits 2 are spaced and separated by an inter-circuit space comprising only the bus bars 4. In other words, the printed circuits 2 do not touch each other, so that between each printed circuit 2 there is an empty space (i.e. a space not comprising a printed circuit 2).
[0058] According to a preferred embodiment, the printed circuits 2 are aligned along an axial direction A, so that the electronic circuit 1 has the appearance of a strip oriented along the axis A.
[0059] Folding and positioning around a motor
[0060] In a particularly advantageous manner, the bus bars 4 are foldable, and more particularly, each portion of bus bar 4 present in an inter-circuit space 6 is foldable.
[0061] Thus, in a particularly advantageous manner, in the inter-circuit spaces, the bus bars are folded so that two adjacent printed circuits 2 are located in two intersecting planes.
[0062] Preferably, the electronic circuit 1 is adapted to be positioned around a circular electric motor. Also, in this context, the bus bars 4, in the inter-circuit spaces 6, are folded so that the set of printed circuits 2 define facets of a substantially hemispherical envelope.
[0063] Folding in the form of a substantially hemispherical envelope very advantageously allows the electronic circuit 1 to be pressed against a circular electric motor, as shown in [Fig.l].
[0064] Manufacturing process
[0065] According to a second aspect, the invention relates to a method of manufacturing the electronic circuit 1.
[0066] The manufacturing process notably comprises the following steps: (a) positioning at least one bus bar 4 on at least two first distinct layers of printed circuits 2, adjacent and separated by a space to connect them while maintaining an inter-circuit space 6 in which there is only said at least one bus bar 4; (b) Stacking and laminating at least one second printed circuit layer 2 on said at least one bus bar 4 and a corresponding first layer, to bury said at least one bus bar 4 between the two layers; (c) bending said at least one bus bar 4 in each inter-circuit space 6.
[0067] In addition, step (c) may comprise the following steps: (cl) bending said at least one bus bar 4 in each inter-circuit space 6 with a bending tool; (c2) Depositing an electrical insulator on said at least one folded bus bar 4 in each inter-circuit zone.
[0068] Typically, step (cl) can be carried out using a machine for force-fitting electronic components, called a “press-fit” machine. This type of machine has the advantage of developing sufficient force for bending the busbars 4 while having a precision suitable for handling electronic components.
[0069] Of course, any type of machine can be used to bend the busbars 4, as long as the bending can be carried out without damaging the printed circuits 2.
[0070] According to a preferred embodiment, the stacking is carried out after having implanted all of the electronic components on the printed circuits 2.
[0071] During bending, it may happen that an insulating coating present on the bus bars 4 is locally abraded by the bending machine;
[0072] Also, it may be provided in step (c2) to redeposit insulating coating on the bent bus bars, to guarantee good electrical insulation of the electronic circuit 1.
[0073] Turbomachine
[0074] According to another aspect, the invention relates to a turbomachine comprising at least one electronic circuit 1 according to the invention.
[0075] Preferably, the electronic circuit 1 is folded to form a faceted hemispherical envelope and is placed on a stator of a circular electric motor.
[0076] Aircraft
[0077] According to a final aspect, the invention relates to an aircraft comprising at least one turbomachine according to the invention.
Claims
Claims
1. Electronic circuit (1) comprising a plurality of printed circuits (2) connected by at least one bus bar (4), each printed circuit (2) comprising at least two superimposed layers enclosing at least a portion of said at least one bus bar (4), so as to bury said at least one bus bar (4), at least one of the printed circuits (2) having, on a first of its two layers, a high-power electronic network, and having on a second of its two layers, a low-power electronic network.
2. Electronic circuit (1) according to claim 1 having printed inter-circuit spaces (6) which only comprise said at least one bus bar (4)
3. An electronic circuit (1) according to claim 2, wherein said at least one bus bar (4) in each inter-circuit space (6) is foldable, so that two adjacent printed circuits (2) are located in two intersecting planes.
4. Electronic circuit (1) according to claim 3 wherein said at least one bus bar (4) is folded between two printed circuits (2) so that the set of printed circuits (2) define facets of a substantially hemispherical envelope.
5. Electronic circuit (1) according to any one of the preceding claims, wherein at least one of the printed circuits (2) comprises at least two electrically separated bus bars (4).
6. Electronic circuit (1) according to claim 5 wherein said at least two bus bars (4) have distinct electrical and / or mechanical properties.
7. Electronic circuit (1) according to any one of claims 1 to 6, wherein at least one of the printed circuits (2) has a connector for connecting at least two elements among the two layers and the at least one bus bar (4).
8. A method of manufacturing an electronic circuit (1) according to any one of the preceding claims in combination with claim 3, comprising the following steps: (a) positioning at least one bus bar (4) on at least two first distinct layers of printed circuits (2), adjacent and separated by a space to connect them while maintaining an inter-circuit space (6) in which there is only said at least one bus bar (4); (b) Stacking and laminating at least one second printed circuit layer (2) on said at least one bus bar (4) and a corresponding first layer, to bury said at least one bus bar (4) between the two layers; (c) folding said at least one bus bar (4) in each inter-circuit space (6).
9. A method according to claim 8, wherein step (c) comprises the following steps: (cl) bending said at least one bus bar (4) in each inter-circuit space (6) with a bending tool; (c2) depositing an electrical insulator on said at least one bus bar (4) bent in each inter-circuit area.
10. Turbomachine comprising a circular electric motor having an external casing and an electronic circuit (1) according to any one of claims 1 to 7, fixed against said casing.
11. Aircraft comprising at least one turbomachine according to claim 10.