Electricity: motive power systems – Synchronous motor systems – Armature winding circuits
Reexamination Certificate
2000-03-23
2001-12-04
Ro, Bentsu (Department: 2837)
Electricity: motive power systems
Synchronous motor systems
Armature winding circuits
C361S699000, C361S702000, C363S141000
Reexamination Certificate
active
06326761
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a power electronics device for controlling an electric machine.
2. Description of the Related Art
Electric machines comprise a wide variety of machines for converting energy from one form to another and include generators and motors. Among the many types of electric machines, synchronous machines are used for generating electrical energy. The electrical energy generated by the synchronous machine may then be applied to an extremely wide range of loads. These loads are usually combined into electrical networks which may, for example, comprise an on-board electrical network for a vehicle. When an electric machine is used in a vehicle, installation space is limited. Therefore, only a small installation space is available for the electric machine and the components required for operating the electric machine including a power electronics device. Accordingly, the individual components are required to be as compact and space-saving as possible. Furthermore, the engine or motor of a vehicle supplies the power to the individual components. Therefore, these components and specifically the power electronics must be particularly efficient to limit the amount of power consumed by the engine. This applies in particular in the vehicle industry sector, where new electrical components are always being introduced.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a power electronics device for controlling an electric machine which is efficient and which has a compact design and therefore only a low installation space requirement.
According to an embodiment of the present invention, the object is achieved by a power electronics device for controlling an electric machine having a power section comprising a plurality of capacitors and a plurality of power semiconductors connected to a power busbar. The power electronics device further comprises a control device for controlling the power section and a cooling device which is connected to the capacitors, the power semiconductors, and/or the control device such that a thermal exchange occurs or can occur between these component(s) and the cooling device.
The power electronics device of the present invention has a compact design in which the individual components of the power section, the control device, and the cooling device are arranged in an optimized manner. This arrangement allows the power electronics device to have a low space requirement. As a result, the power electronics device according to the present invention is particularly suitable for use in the vehicle sector.
The configuration of the power electronics device depends to a very great extent on the required voltage level. For this reason, the number of capacitors and power semiconductors may vary depending on the application for which the power electronics device is designed. Therefore, the invention is not restricted to a specific number of capacitors and power semiconductors.
Power semiconductors which may be used are preferably MOSFETs, IGBTs or the like. However, other types of power semiconductors may also be used. The choice of the suitable power semiconductors is made in accordance with the power requirements of the power electronics device.
For example, if the power electronics device is to be used for example within the framework of a 42 V on-board network planned by the car industry, via which in the future newly introduced electrical components, such as windshield heating, electric valve drive and so on are to be operated, the power semiconductors will preferably comprise MOSFETs. If higher voltages are used, IGBTs are used.
The individual capacitors and power semiconductors are connected to a power busbar and are wired up, i.e., electronically interconnected, via the latter. The power busbar preferably consists of copper, but may comprise any electrically conductive material.
The control device is also provided in the power electronics device and may, for example, be constructed as a control circuit board. The control device preferably comprises surface-mounted devices (SMD) connected to a control circuit board using surface-mounting technology (SMT) and performs all the control, monitoring and regulating functions of the power electronics device including driving the power semiconductors. The control device preferably comprises a powerful microcontroller for controlling the power electronics device with all the functions of the microcontroller being predefined via a Controller Area Network (CAN) bus. Furthermore, the control device also has a device for the voltage supply. Depending on the requirements of the particular application, the control device may also comprise further elements.
The power electronics device according to the present invention further comprises a cooling device to dissipate the heat loss produced during the operation of the power electronics device in the capacitors, the power semiconductors, and/or the control device. The cooling device is connected to at least one of the above-mentioned elements in such a way that thermal exchange occurs or can occur between these and the cooling device. As a result, heat loss produced during operation is dissipated via the cooling device. The cooling device may, for example, be produced from a metal such as aluminum or the like.
The cooling device may advantageously be formed as a profiled element. For example, the cooling device may comprise an extruded profile or deep-drawn profile formed of a metal such as aluminum or other material which conducts heat. As a result, the cooling device may be produced particularly simply and cost-effectively.
The cooling device may comprise an essentially U-shaped cross section. Of course, depending on the requirement of the particular application in which the power electronics device is used, other cross sections such as, for example, an L-shaped cross section or the like, may also conceivably be used for the cooling device.
In a further refinement, the cooling device may comprise at least one cooling duct for conducting a cooling medium. The cooling duct allows the cooling medium to flow through the cooling device to further facilitate the dissipation of the heat loss. The cooling medium may, for example, comprise water or the coolant used in the cooling system of a vehicle.
In one embodiment according to the present invention, the cooling device comprises two lateral limbs and a base region. A cooling duct is provided in at least one of the lateral limbs and/or in the base region of the cooling device to facilitate the dissipation of the heat loss.
In a specific embodiment, an essentially U-shaped configuration of the cooling device ensures lateral cooling and cooling toward the bottom and from the bottom of the power electronics device.
In a further refinement, at least one connecting element is provided to connect the at least one cooling duct to a source of the cooling medium. The feed and the discharge of the cooling medium may be regulated via the at least one connecting element.
If the power electronics device is used in a motor vehicle, for example, the source of the cooling medium may comprise the conventional cooling circuit of the internal combustion engine. In this embodiment, the connecting element of the cooling device may be connected to the cooling circuit of the internal combustion engine, so that the cooling water circulating in the internal combustion engine also flows through the cooling device of the power electronics. In this embodiment, additional coolers, pumps or other equipment for a cooling system is not required because the equipment already exists for the cooling circuit of the internal combustion engine of the motor vehicle. This arrangement has particular advantages with regard to the costs and the space requirement of the power electronics device.
In a further embodiment, the capacitors may be arranged within a chamber formed by the lateral limbs and the base region of the cooling device. This arrangement ensures the lateral cooling
Cohen & Pontani, Lieberman & Pavane
Mannesmann Sachs AG
Ro Bentsu
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