Patent Application
20090299918
Wireless delivery of power may be used to provide power to a load. For example, U.S. patent application Ser. No. 12/018,069, filed Jan. 22, 2008, entitled “Wireless Apparatus and Methods”, the disclosure of which is herewith incorporated by reference, describe wireless transfer of power to a load. This may be done by forming a magnetic field and receiving a magnetic field in a resonant antenna that is resonant with at least one characteristic of a magnetic field. The power transmission may also be done inductively. The magnetic delivery of power, however, has the advantage of being capable of delivering power over a longer distance.
The present application describes wireless delivery of power to a mobile powered device such as an automobile. An embodiment describes how power can be delivered to the automobile in a number of different locations.
These and other aspects will now be described in detail with reference to the accompanying drawings, wherein:
Delivery of electric power to automobiles may become more prevalent as electrically powered automobiles enter and occupy a more significant portion of the market. For example, as of the time of writing of this document, there are many different forms of hybrid automobiles which operate based both on internal combustion engines, and also on stored charge in a battery. There are fewer forms of electric automobiles such as plug-in hybrids or plug-in electric vehicles.
Commercial success of such a vehicle would require that either the vehicle have a sufficient mileage range to make an entire round-trip without recharging, or that the user recharge the vehicle at some intermediate point. Currently, there are vehicle charging stations mostly associated with public areas, for example airports and public parking places. This is done in many ways as a public service to allow or encourage more people to use electric automobiles. However, this is not a long-term practical solution.
The inventors also recognize that it may be desirable to wirelessly deliver power to an electric powered mobile device, such as an automobile.
The battery 102 is shown driving an electric motor 104, 106 which may drive vehicle wheels, for example.
In the embodiment, the automobile also includes at least one magnetic resonant antenna shown as 110 formed from an inductive loop 111 in parallel with a capacitor 112. This forms an LC circuit with a relatively high Q, for example a Q that is higher than 1000. In the embodiment, when the antenna 110 comes into range of an appropriate transmitter, it receives a magnetic signal from that transmitter, and the receiving circuit 115 converts that power into output current. That power can be used for directly driving the motors 104, 106, but more preferably is used for charging the battery 102.
In the embodiment, the battery is automatically charged whenever the antenna 112 comes into range of a wireless charging circuit of appropriate type, e.g. the right frequency. A number of different places, such as parking lots, and more specifically public places, may have appropriate chargers such as 150 in specified locations. In the embodiment, the charger 150 may be located within the ground near a parking space.
Charger 150 may include a coil 152, a capacitor 154, and a charging circuit 156 that produces signal of appropriate frequency for magnetic transmission. Charger 150 may produce a magnetic field shown generally as 158. Whenever an appropriate vehicle comes into range of the magnetic field 158, it may receive power from that magnetic field, and hence be charged thereby.
The charger 150 also includes an information detecting part. This may be a send and receive portion 160 that wirelessly detects a unique identifier indicative of the vehicle 100. In one embodiment, the vehicle 100 may include an RFID device 121 that uniquely identifies the vehicle. Information from the RFID device may be detected by the send and receive device 160. Another embodiment may use a camera or scanner to detect some written item on the automobile, e.g., the license plate or serial number or barcode on the automobile.
In operation, the vehicle charging operation may operate as follows.
A premium over utility costs may also be added to the bill. In essence, this system is reselling power from the electricity manufacturer, to any vehicle with an appropriate account that comes into range of the antenna.
Another embodiment may recognize that the detection of an ID could be cloned, and use encryption techniques to verify the ID. For example, one embodiment might use a real-time token type system. The vehicle has a real time clock which is used to display time. The time is encrypted by the vehicle's private encryption key. The controller has a decryption key that can decrypt the encrypted message. The controller thereby 1) checks whether the value can be decrypted, and 2) checks whether the time is correct (to avoid reuse of a previously-sent message).
This cryptographically determines whether the power delivery is accurate by the controller 180. Power is allowed to be dispensed only if an encrypted value properly agrees with the proper encryption code and proper token time.
Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way. This disclosure is intended to be exemplary, and the claims are intended to cover any modification or alternative which might be predictable to a person having ordinary skill in the art. For example, other forms of power transfer can be used.
Also, the inventors intend that only those claims which use the words “means for” are intended to be interpreted under 35 USC 112, sixth paragraph. Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims. The computers described herein may be any kind of computer.
