It is common practice in the electric propulsion of modern motor vehicles, such as hybrid vehicles, for DC current to be fed to an inverter which is then used to transform the
DC current into a mostly three-phase AC current. This AC current is fed to a drive motor. Since high currents are carried on the lines that connect the inverter to the drive motor, these lines typically have a cross section of between 25 mm2 and 50 mm2. As these cables are relatively thick, it has proven to be effective for each phase to be fed separately by an individual electric line to the drive motor. Because the inverter induces strong electromagnetic interference into the line, a shield individually shields each line against electromagnetic interference leakage from the cable. The drive motor can be electroconductively connected to the inverter by an electrical plug connection. It is also customary for the shield of each individual line to be pluggably connected to that at the drive motor, the shields then being electroconductively interconnected within the drive motor.
However, it has been found that high interference currents act upon each shield during operation of the motor vehicle due to electromagnetic interference. The transition resistances within the electrical plug connection cause a considerable power loss to occur in conjunction with the high current intensities. This power loss, in turn, leads to a substantial heating of the plug connection and can thereby unacceptably load the plug connection. In order not to overheat the electrical plug connection, the current intensity carried by the electrical line is mostly suitably adapted or limited.
There may, therefore, be a need to provide an electrical connecting structure that will make it possible for the heat generated by the interference current in the shield to be reduced in the electrical plug connection.
In accordance with a first exemplary embodiment of the present invention, an electrical connecting structure having an electrical connector is provided with an electrically insulating connector housing. To permit the transmission of high currents, the electrical connecting structure is adapted for electroconductively connecting the electrical connector to an electrical mating connector that is permanently connected to an electrical unit. The connecting structure has a first electrical line, the first electrical line being adapted for conducting a first electric current at a first phase angle. The connecting structure has a second electrical line, the second electrical line being adapted for conducting a second electric current at a second phase angle. The first phase angle and the second phase angle are temporally offset from one another. The first line features a first shield for protecting against electromagnetic interference. The second line features a second shield for protecting against electromagnetic interference. The first shield is detachably and electroconductively connectable to a third shield configured in the mating connector. The second shield is detachably and electroconductively connectable to a fourth shield configured in the mating connector. The first shield and the second shield differ from one another. The first shield and the second shield are electroconductively interconnected within the electrical connecting structure.
An electrical unit is understood to be an electrical consumer or an electrical energy source. The electrical lines may have a cross section of 25 to 50 mm2, for example, and, at a cross section of 35 mm2, are adapted for transmitting 150 A per line, for example. On the one hand, electromagnetic interference is induced into the electrical conductor by the inverter. On the other hand, the electrical conductor itself generates electromagnetic interference due to magnetic induction. The first and the second electric current may be an AC current supplied by an energy source, for example. The first and the second current may also be pulsed DC current, it being possible for the pulsed DC current to be produced by an inverter and/or in response to the fluctuating power demand of electrical consumers, such as electric motors. Accordingly, electromagnetic interference or interference currents may not only occur in an electrically conductive connection of the inverter to an electrical consumer, but also in an electrically conductive connection of the inverter to a direct current source, such as a vehicle battery, for example. An electrical unit may be an electrical consumer, a battery, a DC-DC converter or also a charging module for the battery, for example. The idea underlying the present invention is that the electrically conductive connection of the first and second shield within the electrical connecting structure, this being provided in the electrical connector or at least in the vicinity thereof, couples the electromagnetic interference of the first conductor into the second shield of the second electrical conductor and vice versa. Thus, ideally, the electromagnetic interference generated by a source of interference, for example, the inverter, and conducted along the first conductor due to the temporal phase shift, respectively the first shield extending in parallel to the first conductor, to the electrical connector, respectively the connector housing thereof, may be coupled into the second shield and fed back along the second conductor, respectively the second shield extending in parallel to the second conductor, to the source of interference. Thus, theoretically, the interference current present in the first shield would not cause any power losses to occur in the electrical plug connection that would result in heat being input into the electrical plug connection, thus into the electrical connector and/or the electrical mating connectors. Due to deviations from the ideal case, for example, due to the temporal offset of the phases not exactly corresponding to the fraction of 360°, the current intensities to be transmitted to the drive motor changing, or transition resistances being present upon detachable connection of the individual shields, it is not possible for the entire interference current of the first shield to be conducted into the second shield; rather a portion of this interference current is still carried through the connector housing to a ground of the electrical unit. The result is a substantially lower power loss. The maximum total heat load that the electrical plug connection may be subjected to is composed of the ambient temperature in which the electrical plug connection is operated, the heating of the electrical conductor caused by the current intensities, and the heating generated by the power loss in the shields. Thus, the heat saved in comparison to the related art due to the reduced power loss may be utilized, for example, for transmitting a higher current via the specified electrical conductor. The heat saved in comparison to the related art may also be utilized for operating the electrical connector at a higher ambient temperature. The electrical connector generally features a connector housing that is fabricated of electrically non-conductive plastic.
In accordance with another exemplary embodiment of the present invention, the first shield and the second shield are electroconductively interconnected outside of the electrical connector.
Thus, most of the interference current caused by the inverter and induced into the shield of the electrical conductor is not directed through the electrical conductor. Merely a small portion of the interference current is conducted into the electrical unit. The power loss in the form of heat in the plug connection is thereby significantly reduced.
In accordance with another exemplary embodiment of the present invention, the first shield and the second shield are electroconductively interconnected close to the entry thereof into the electrical connector.
Due to the proximity of the electrically conductive connection of the first shield and the second shield to the electrical connector, virtually no electromagnetic interference currents are able to be induced into the shield of the electrical connector through the electrical line portion remaining between the electrically conductive connection and the electrical connector.
In accordance with another exemplary embodiment of the present invention, the first shield and the second shield are electroconductively interconnected within the electrical connector.
Such a structural design readily allows the first shield and the second shield, for example, to be electroconductively interconnected.
In accordance with another exemplary embodiment of the present invention, an electrical configuration is provided with an electrical connecting structure described in the preceding.
The electrical connecting structure electroconductively interconnects an inverter and an electrical unit.
In accordance with another exemplary embodiment of the present invention, the electrical connecting structure of the electrical configuration has a first electrical plug connector having a first electrically insulating connector housing, and a second electrical plug connector having a second electrically insulating connector housing. The first electrical connector is electroconductively connected to the electrical unit. The second electrical connector is electroconductively connected to the inverter. The first shield and the second shield are electroconductively interconnected twice.
In the case of the first connector, the electrically conductive connection may be established within or outside of the connector housing and, in the case of the second connector, likewise within or outside of the connector housing thereof. When the electrically conductive interconnection of the first shield and of the second shield is established outside of the connector housing, each electrically conductive connection is then configured close to the entry of the lines into the particular connector.
In accordance with another exemplary embodiment of the present invention, a motor vehicle is provided with an electrical configuration as described in the preceding.
It is noted that ideas pertaining to the present invention are described herein in the context of an electrical connecting structure, an electrical configuration having such a connecting structure, and a motor vehicle having an electrical configuration. It is evident to one skilled in the art that each of the described features may be combined with one another in different ways in order to thereby arrive at other embodiments of the present invention.
Specific embodiments of the present invention are described in the following with reference to the figures. The figures are merely shown schematically and are not true-to-scale.
This makes it clear that, by creating two current paths 50, 60, the interference current introduced through shield 12 into electrical connector 4-mating connector 6-combination is diverted virtually losslessly via third shield 14 from electrical connector 4-mating connector 6-combination. The electrically induced interference currents incoming in first shield 12 may be directed by second shield 14 back to a producer.
In accordance with the preceding description, there are also two current paths 50, 60 here. However, since first current path 50, generally composed of the two fifth transition resistors R5, is situated outside of electrical connector 4-mating connector 6-combination, first current path 50 does not contribute to a power loss within electrical connector 4-mating connector 6-combination. As already described, downstream of branch connection 34, transition resistors R1, R4, R2 and R3 are merely acted upon by a significantly lower current intensity of approximately 5 A, for example. Accordingly, the power loss arising in the electrical connector 4-mating connector 6-combination is reduced in comparison to conventional connectors.
Since the power losses also lead to a heating of the electrical connector 4-mating connector 6-combination, given a correspondingly lower power loss, this electrical connector 4-mating connector 6-combination is also heated less. At this point, assuming that the electrical connector 4-mating connector 6-combination may be operated at a predetermined temperature, the lower heat produced by the lower power loss may then be utilized, for example, for increasing the current intensities transmitted by electrical lines 8, 10. The lower heat input produced by the power loss may also be utilized for operating the electrical connector 4-mating connector 6-combination at a higher ambient temperature.
Number | Date | Country | Kind |
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10 2011 088 333.9 | Dec 2011 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2012/070361 | 10/15/2012 | WO | 00 |