Electricity: measuring and testing – Measuring – testing – or sensing electricity – per se – Magnetic saturation
Reexamination Certificate
2000-03-30
2002-04-30
Karlsen, Ernest (Department: 2858)
Electricity: measuring and testing
Measuring, testing, or sensing electricity, per se
Magnetic saturation
C324S11700H, C324S126000
Reexamination Certificate
active
06380728
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bus bar for connecting electrical components of a power electronics device for controlling an electric machine and an arrangement of the bus bar for measuring current and for connecting to the power electronics device for controlling an electric machine.
2. Description of the Related Art
Bus bars are used as a common connection point to connect electrical components to one another and to supply them with the necessary current. That is, a bus bar comprises a conductor or conductors for collecting electric currents and distributing them to electric components. For example, bus bars are used in particular in a power electronics device for controlling electric machines.
The electric machines controlled by the power electronics device having a bus bar may include synchronous machines for generating electrical power. The electrical power generated by the synchronous machine is then made available to an extremely wide range of loads. These loads are usually connected into electrical networks. An example of the electrical network includes an on-board networks for motor a vehicle. When the electric machine is used in a motor vehicle, limited installation space is available for the electric machine and for the components needed to control the electric machine, which also include the power electronics device. The individual components must therefore be configured to be as compact and space-saving as possible while simultaneously being sufficiently powerful. This is especially important in the motor vehicle industry, where new electrical components are constantly being introduced.
The power electronics device mentioned above is used to drive an electric machine. For this reason, high currents flow through the power electronics device during operation. Furthermore, to adequately regulate and monitor the electric machine, the currents flowing through the power electronics device must be measured.
In the prior art, separate current-measuring devices have been used for these current measurements. These current-measuring devices generally comprise a sensor and an evaluation device connected to said sensor. To carry out the current measurement, the sensor is connected to a conductor through which the current to be measured flows. In one known embodiment for measuring current, it is necessary for the conductor in which the current is measured to be present as an independent component. This conductor then has to be mounted on an appropriate base structure. The drawback with such an embodiment, however, is that a large number of components are needed, and contact has to be made between all of them one after another. Thus, the conductor used for the current measurement must be mounted on the base structure. The sensor must then be mounted and contact must be established with this current conductor. As a result, the production of such an arrangement for measuring current is complicated in constructional terms and therefore costly. Therefore, this arrangement has a particularly detrimental effect in the speed of mass production and in keeping down the cost of the automobile.
In a further known embodiment for measuring current, the current-carrying conductor used for current measurement is applied to a printed circuit board. Contact is then made between this current conductor and the sensor of the current-measuring device. However, the disadvantage here is that the ability of printed circuit boards to carry current is restricted. Current measurement using this technique is limited to a small current class and is therefore not suitable for the power electronics device described above in which high currents have to be measured.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a bus bar with an arrangement for measuring current and power electronics in which even high currents can be measured in a cost-effective and simple device. The object of the present invention is also to avoid the problems of the prior art.
According to a first embodiment of the present invention, the object is achieved by a bus bar constructed in one or more layers for connecting electrical components for a power electronics device for controlling an electric machine. According to the present invention, the bus bar is defined in that it has at least one portion with a shaped section that is connected or connectable to a current-measuring device.
In this way, electrical currents may be measured in a manner which is simple to construct and inexpensive. The present invention is based on the basic idea that the separate current conductors which were previously required for the current measurement may be eliminated. Instead of a separate conductor, the current conductor is now formed by a portion of the bus bar. This portion is a shaped section which may be formed, for example, as a projection. In principle, the present invention is not restricted to a specific number or shape of the particularly formed portions of the bus bar. Instead, the configuration criteria are given by the requirements of the particular application.
Since the portion with a shaped section which is used for current measurement is a permanent constituent of the bus bar, the current-measuring methods used for measuring the current may be implemented cost-effectively even for high currents. To this end, the bus bar, and in particular the portion with a shaped section, must be designed appropriately. In addition, the previously required step of mounting the separate conductor used for the current measurement on a base structure is eliminated. As a result, the construction is simplified and the production costs are also reduced. The bus bar constructed in accordance with the present invention avoids the disadvantages described in the prior art.
The at least one portion of the bus bar having a shaped section provided according to the present invention is connected or connectable to a current-measuring device, via which the current flowing through the at least one portion is measured. More detailed explanations relating to the current-measuring device and to its connection with the portion of the bus bar follow in the further course of the description.
The bus bars according to the present invention may be constructed in one or more layers. If the bus bars are constructed in more than one layer, the individual layers may be connected to one another by a suitable process such as, for example, by a lamination process. In this case, individual layers may comprise conductive material and other layers may comprise an insulating material. The use of bus bars for providing a simple and safe option for supplying different loads with current is well known. However, the complicated cabling used in known bus bar arrangements is eliminated by the present invention such that the use of the inventive bus bar leads to space savings in relation to the installation space. This is particularly advantageous when the bus bar is used in a power electronics device for operating an electric machine in a motor vehicle.
In a preferred embodiment of the bus bar according to the present invention, the bus bar may advantageously be formed from one or more layers of copper or aluminum. Of course, other materials may also be used. However, an important characteristic is that the material used is a good conductor of an electric current. Therefore, the bus bar advantageously comprises one or more layers of solid copper.
The bus bar according to the present invention advantageously has a plate-like basic structure. Bus bars of this type are easily produced and may be connected up to a large number of electrical loads, while requiring only a small amount of installation space.
In a further embodiment, the at least one portion of the bus bar with a shaped section is constructed in the area of one of the ends of the bus bar. In a particular embodiment, the bus bar has a plate-like, rectangular basic structure and the portion with a shaped section is accordingly advantageously constructed in
Tareilus Alfred
Weimer Jürgen
Cohen & Pontani, Lieberman & Pavane
Karlsen Ernest
Mannesmann Sachs AG
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