Patent Application
20110231044
The present invention relates to a power supply system for electric vehicles, and a method for controlling a power supply system.
Electric vehicles in the sense of the present invention are understood to be vehicles equipped only with an electric drive. In addition, this term should also be understood to include so-called plug-in hybrids. Plug-in hybrids are hybrid vehicles having a larger storage for electric power which is rechargeable from the electric power grid. Vehicles of this type thus require a power connector for the connection to the electric power grid during the charging operation. The goal is to minimize the time required for the charging operation because users of such vehicles will base their expectations of convenience on the comparatively short refueling pauses for refueling a vehicle with gasoline or diesel. The charging time may be minimized if the maximum possible power is drawn from the power grid. From today's standpoint, the limiting factor is usually the maximum power drawable from the grid, in particular in the private sector. Power receptacles available for charging an energy storage today are usually protected with a fuse, which must then be reset manually after being triggered when the allowed current is exceeded. To overcome this disadvantage, the maximum allowed charging current drawable from the grid must thus be known to the vehicle when an energy storage to be charged is connected. In this way, is it possible for the charging operation to proceed rapidly and smoothly. This is particularly important if the vehicle is to be charged not only at the home receptacle but also at any receptacles, for example, at the job site, in a parking garage, at a service station, or the like. The charging operation in foreign countries must also be considered particularly critically because different grid voltages, different grid frequencies, a different maximum current and different grid configurations must be expected there. Although the parameters of grid voltage and grid frequency may be detected comparatively easily by the on-board charging circuit, however, this is not readily true of the maximum charging current drawable from the grid via the power receptacle being used. The charging current could be limited in general to a comparatively low value, which could also be made available at any available power receptacle for charging at practically any time even under the least favorable conditions. However, this would result in a comparatively long charging operation. Another alternative would be to install signs indicating the allowed operating parameters on the receptacles and manual input of these operating parameters into the charging circuit at the start of a charging operation. However, this is not convenient and does not rule out operating errors, which could result in a disturbance in the charging operation.
U.S. Published Patent Application No. 2006/0250902 A1 also describes a plug-in hybrid vehicle which is connectable to a power supply grid in such a way that a bidirectional power flow is possible.
An object of the present invention is to provide a power supply system for electric vehicles, which enables the fastest and most reliable possible charging operation of an electric vehicle on a public power grid.
In accordance with the present invention, the charging operation may be optimized in the desired sense through automatic transmission of the allowed operating parameters from the grid to the vehicle on initiation of the charging operation, which is thus largely free of operating errors.
An advantage of the present invention offers is that the driver of an electric vehicle will perceive the charging operation of the on-board energy storage to be as convenient as a traditional stop at a filling station to refuel a vehicle with gasoline or diesel. The aforementioned operating parameters are transmitted in a particularly advantageous manner through suitable coding of a plug connection which is established between a mobile plug and a stationary receptacle in a grid connection station, for example. The receptacle may advantageously have mechanical coding elements, color coding, barcodes or the like as well as any combination of these coding elements which are then detected by a suitably designed plug on the electric vehicle. If a navigation system is present in the vehicle, the location of a grid connection station and the operating parameters prevailing there may also be displayed on the display screen of the navigation system in a particularly advantageous manner. In another advantageous specific embodiment of the present invention, the operating parameters are also transmitted by a transponder system or by a mobile telephone in a wireless, i.e., noncontact, transmission. In the case of a parking facility equipped with multiple parking spaces and grid connection stations such as parking lots, parking garages or the like, the location of available parking spaces having grid connection stations and the particular allowed operating parameters for the charging operation may be displayed already in the entrance area in an advantageous manner. It is also possible to have targeted guidance of an entering vehicle to an optimally suited available parking space having a grid connection station.
Additional advantages of the present invention may be derived from the following description, and the figures.
The present invention is explained in greater detail below based on the figures as an example.
In an electric vehicle 1 equipped with a navigation system, the location of a grid connection station and the operating parameters to be taken into account there may also be displayed on the display screen of the navigation system in a particularly advantageous manner. This is illustrated with reference to
In another example embodiment variant of the present invention, the operating parameters may also be transmitted by a coding superimposed on the voltage curve of charging voltage U supplied in the grid connection station. This is illustrated in
Additional embodiment variants are explained below with reference to
With the growing popularity of electric vehicles, parking facilities such as parking lots, parking garages or the like will in the future be equipped with grid connection stations for electric vehicles.
The power supply system for an electric vehicle designed according to the present invention may be controlled in the following way according to the present invention. At the latest when a plug connection is established between an on-board plug 1.3 and a stationary receptacle 3.2 in a grid connection station 2, allowed operating parameters of stationary power supply grid 3.1 are transmitted to on-board charging device 1.2. Charging device 1.2 then controls the charging operation of on-board energy storage 1.1 in such a way that the charging operation proceeds as rapidly as possible without causing an inadmissible overload on stationary power supply grid 3.1.
In one embodiment variant of the present invention, interface 1.3, 3.2, 50a, 50b between the mobile and stationary components of power supply system 100 is designed advantageously in particular to be bidirectional for data exchange. While on the one hand the operating parameters of the stationary power supply grid may be transmitted to vehicle 1, the charge state of on-board energy storage 1.1 may be reported back in the opposite direction. The grid connection station currently being used by the vehicle may then be deactivated until the departure of the vehicle in order to allocate the remaining resources of the power supply grid to other grid connection stations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 042 677.6 | Oct 2008 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP09/62446 | 9/25/2009 | WO | 00 | 6/6/2011 |
