PCB CONNECTOR

Abstract

A connection assembly for providing electrical connection of a multi-strand wire conductor to another component, comprising a printed circuit board, PCB, whereby the conductor can be connected to a conductive segment or track of the PCB which is also connected to the other component.

Claims

1. A connection assembly for providing electrical connection of magnetic wire conductors to another component, comprising a printed circuit board, PCB, whereby the conductor can be connected to a conductive segment or track of the PCB which is also connected to the other component.

2. The assembly of claim 1, whereby the PCB is a heavy copper PCB.

3. The assembly of claim 1, whereby PCB defines conductive segments separated by insulating segments.

4. The assembly of claim 1, where the magnetic wire conductors form a multi-strand conductor or a single magnet wire conductor.

5. The assembly of claim 4, wherein the multi-strand conductor is a Litz wire.

6. The assembly of claim 4, wherein the other component is also a multi-strand wire conductor or a single magnet wire conductor.

7. An electric motor having a plurality of conductive windings connected to each other by the connection assembly of claim 1.

8. A method of connecting a conductive winding of a motor to another component comprising fixing the conductive wire to a conductive segment of a printed circuit board and electrically connecting the other component to the conductive segment.

Description

BRIEF DESCRIPTION

[0010] Examples according to the disclosure will now be described with reference to the drawings. These are by way of example only and variations are possible within the scope of the claims.

[0011] FIG. 1A shows a fault tolerant winding concept that can incorporate connectors according to the disclosure.

[0012] FIG. 1B shows an alternative fault tolerant winding concept that can incorporate connectors according to the disclosure.

[0013] FIG. 1C shows a distributed winding concept that can incorporate connectors according to the disclosure.

[0014] FIG. 1D shows a concentrated winding concept that can incorporate connectors according to the disclosure.

DETAILED DESCRIPTION

[0015] As is known, and briefly discussed above, electric motors include a rotor and a stator, conductive coils and magnets, to generate electrical energy. Such motors are well known and will not be described in detail. Connections have to be made between the various windings in the motor as well as connections between the motor parts and external systems.

[0016] Many motors use multi-strand wire bundles to form the conductors for the windings so as to minimise eddy currents. It is difficult to connect such windings to each other or to other components without negating the multi-strand effect and/or creating an increased resistance at the connection that results in increased losses.

[0017] In conventional motors, different windings are electrically connected to each other by physically overlapping the windings and/or by providing end-windings extending from the ends of the motor where conductors of different phases of the motor pass over the end-windings to form a connection with each other. The end-windings are large and it is, as mentioned above, difficult to provide the necessary electrical and magnetic isolation when the conductors physically overlap each other. Connecting the conductors to other components of the motor or of external systems often uses soldering or brazing which fuses the multi-strand wires together at the ends of the coils.

[0018] The solution provided by this disclosure is to provide connections for such conductors either to each other or to other components by means of a printed circuit board (PCB) and, in particular, a heavy copper PCB. The heavy copper PCB allows for the segmentation of the copper into a number of layers, allowing the PCB to be used at high frequencies and for electrical isolation between the different windings since the windings do not need to physically overlap in order to be electrically connected. Using a PCB enables, for example, the windings to be segmented and electrically connected via PCB traces, which improves their use in high frequency operations.

[0019] Further, the PCB can be designed such that a bundle of multi-strand wires can be terminated with a stud or a crimp at the ends of the wires, and the stud or crimp physically attached to the PCB by means of the stud without the need to solder or braze the wires. This allows for quick assembly and provides a lower resistance path and a more reliable connection than a solder or braze. Particularly at higher temperatures, soldered or brazed connections can fatigue and present a higher resistance path. Other interconnect technologies can also be adopted, depending on the application e.g. a compliant pin.

[0020] In conventional motors, magnetic wires will physically overlap. The physical location of the wire becomes less controlled or repeatable which gives rise to a risk of insulation damage between the wires or segments. This problem can be aggravated by vibration or movement as is, therefore, more of an issue in vibrational environments e.g. in aircraft. Connection via traces of a PCB means that different segments of the same winding can be connected together in a way that the physical location of each conductor can be controlled precisely, thus minimising the risk of insulation damage caused by relative conductor movement- and that different phases and winding channels can be suitably isolated from each other by appropriate spacing either radially or axially between the traces of the PCB. The use of a PCB can be particularly advantageous in making fault tolerant machines more fault tolerant.

[0021] Furthermore, the heavy copper PCB is better able to conduct heat away internally within the PCB to an external cooling medium. Further, the use of the heavy copper PCB can reduce copper conduction losses due to the increased fill factor, and can facilitate improved thermal management of the conductor conduction losses by providing a suitable thermal interface; in contrast, conventional insulation on copper wires has very low thermal conductivity, which hinders thermal management. The relatively high thermal conductivity through the substrate reduces temperature increase within the PCB.

[0022] FIG. 1A shows one fault tolerant winding concept where different phases are connected on a PCB. Here, alternate windings 1, 5 and 9 are connected to each other by traces 10, 50, 90 and the intermediate windings 3, 7, 11 are connected to each other by traces 30, 70, 110. The windings are separated by gaps 2, 4, 6, 8, 10 and 12. This is an example showing one particular motor topology. There are, however, many other configurations which could be used, depending on the specific application.

[0023] In another example, two groups of adjacent windings are formed i.e. windings 1, 3 and 5 are connected to each other and windings 7, 9 and 11 are connected to each other.

[0024] The different concepts can be easily formed on a PCB as required for a given application by designing the traces accordingly.

[0025] FIG. 10 shows the overlap between different phases in a distributed winding concept and FIG. 1D shows the overlap between phases in a concentrated winding concept. Any of these concepts can be realised by forming appropriate PCB designs.

[0026] The use of a PCB as an interconnecting mechanism for all connections provides consistency and ease of design and manufacture. A heavy copper PCB is able to carry higher currents without problems of isolation or losses. The use of a PCB instead of overlapping of magnet wire end-windings also results in a more compact motor design.