It always was strange that nearly all of the focus for charging on-road and off-road vehicles has been on the awkward concept of a plug when we all have contactless electric toothbrushes and widespread contactless charging of laptops and mobile phones is being planned under global standards. Bizarrely, progress on the necessary high current standards for inductive ie contactless charging of vehicles has been poor even though the best systems no longer waste 20% of power, only 5% being achieved by some. However, it does seem to be true that the highest current, fastest charging is technically impossible without plugs at present.
Nevertheless, the interest in contactless charging of vehicles is now moving well beyond the thirty or so manufacturers and developers of proprietary, incompatible systems. There could even be some rocket fuel put behind standards writing given the rapidly increasing interest of many major automotive manufacturers and of bus and other operators.
For example, this month, it was reported that Daimler AG and Conductix-Wampfler have elaborated the basics for wireless charging of electric vehicles in a research project cofunded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit, BMU) in Germany. Main target of the project "wireless charging" is a safe, automotive grade charging system with maximum efficiency and minimum weight and package.
They continue to evaluate everyday usability of wireless charging including advantages and disadvantages in comparison with charging by plug and cable. Not surprisingly, as early as a few days into the field test the advantages customer comfort and charging safety by the automated charging process were clear.
The testing is focused on the basic charging process where this system loses only 10% of power - only slightly beneath cable based solutions, if all components from socket to battery are taken into account.
There was an evaluation of the first driving-experiences with study participants who had to drive onto the optimum charging position. After two or three exercise runs this could be well achieved supported by parking assistance functions. This particular system tolerates smaller deviations within the range of a few centimeters without noteworthy loss of charging efficiency or transferable power and it had good results regarding electromagnetic compatibility. Future engineering work will optimize this and improve efficiency and to develop solutions for a series application.
The prototypes built within the project are based on the B-Class E-CELL with range extender equipped with an electronic rectifier and a collector coil integrated into the under body cover. The main components are the supply electronics and the external charging coil, which was realized in two variants - as an above ground and beneath ground coil. There is wireless communication between infrastructure and car, the driver assistance function of driving onto the position above the charging coil, the automatic start of the charging process and the vehicle identification. In the area between the coils, object detection avoids risks caused by metal items that should not be there getting hot such as the cat collar problem.
Detailed provided the foundation for the first layout of the inductive transfer components with automotive specific requirements and their optimization regarding package and weight. Comprehensive system simulations served to validate the designs.
Conductix-Wampfler developed all components of the system - it was already expert in inductive power transfer in industrial equipment. Indeed, it has installed wireless charging for electric buses in Genoa and Turin in Italy. These have been in operation since 2003.
Daimler has defined the car charging functions and made the assistance system for driver support. The coil integration within the underbody cover of the cars was designed and supplied by Röchling Automotive. Two inductive charging stations are in the field at the Daimler-Engineering-Location Böblingen-Hulb and are intensively used. The potential optimization regarding package, weight and integration in future vehicle model lines is now clear and being developed. Small commercial vehicles and buses come next.
National and international standardization activities are now expected to guarantee interoperability of inductive charging systems of different suppliers and vehicle manufacturers.
For more attend Electric Vehicles Land Sea Air USA 2012,where Phoenix International - A John Deere Company (leader in agricultural vehicles), BMW (cars etc), Mitsubishi Motors (small commercial vehicles and cars), Daimler AG (commercial and military vehicles and cars) and Toyota (leader in electric forklifts, cars, buses) will present. Uniquely, a large number of electric vehicle manufacturers not seen in conventional EV events will present including WheelTug airliner electrification on the ground, Pipistrel manned electric aircraft, University of Michigan unmanned solar aircraft, SolTrac electric farm tractors, Monterey Bay Aquarium Research Institute Autonomous Underwater Vehicles AUVs. Many manufacturers of industrial, commercial, military, e-bike, cars and other EVs will be there. At last you can meet those responsible for the majority of the hybrid and pure electric vehicle market and they all need components!! Most are prosperous growing businesses not reliant on government support that can be withdrawn at any time.
