A major project goal was to assess the degree of optimisation of commercially available components that was necessary for these to be deployed in an inductive energy transmission system with a power range of up to 60 kW for the continual provision of traction energy and for the recharging of vehicle batteries. Furthermore, the question of whether energy can continue to be transferred even when the vehicle is moving at high speeds was to be examined.
The project also aimed to ascertain which coil topologies were best to deploy for the roads and the vehicles. In determining the suitable coils, factors such as weight, volume, materials used and road construction needed to be taken into account. Technical and organisational interfaces as well as milestones were established, based on a project plan that determined the goals for each of the companies associated with the project. As part of regular recurring project status meetings, technical questions arising from project work in progress could be resolved and overall timing coordinated. The project schedule was thereby updated according to the progress made by all involved parties.
Diverse technical implementation methods were examined using numerical models and computer-aided simulations to assess their potential suitability. After defining an implementation method that appeared suitable (derived from the simulation results), various iteration steps were required on the path to an optimal configuration. At each iteration step, project partners consulted with one another in regard to any potential adjustments of the technical interfaces. At the conclusion of this iterative process comprising modelling adjustments, simulations and laboratory tests, it was shown that the simulation results and measured analyses recorded a high degree of conformity, both in terms of individual components and the complete system at the test circuit in Lathen, in the Emsland region of Germany.
The project results prove that inductive energy transmission for stationary and dynamic applications is also suitable for deployment at higher rates of energy transmission (up to 60 kW within the framework of this project), with minimal energy loss. Prototypes of coils for both the vehicle and roads as well as power electronic components for the road side supply of power and for connection to the energy storage on the vehicle side were designed, modelled, simulated, manufactured, assessed, integrated in vehicles and tested on a test track. The prototypes are available for further testing.
Within the framework of the special focus on examining technologies in the Bremen/Oldenburg model region, those involved in the project could show that inductive energy transmission represents a very good technical solution for the continual provision of traction energy for electric vehicles. The deployment of this technology appears to be particularly promising on fixed routes that include stationary intervals such as at bus stops, around intersections or at urban loading zones.
With the completion of the project, a test track for the practical field tests of components for stationary and dynamic induction energy transmission systems is now available. The test track and knowledge acquired throughout the project — especially by German companies — will help to simplify the technical design of forthcoming inductive energy transmission system components. Furthermore, these companies can now fall back on existing test capacities and need not necessarily invest in individual test benches. This represents a contribution to ensure that these companies maintain or increase their level of competitiveness in this field.
The project demonstrated that commercially available components — particularly power electronic modules — are not implementable for high performance inductive energy transmission systems without elementary changes or adjustments. To ensure efficient energy transmission and keep the number and volume of parts and materials required at a minimum, a relatively high frequency for the electromagnetic alternating field for energy transmission should be used. Current commercially available components usually do not meet these demands or are too costly. The search for suitable or customisable commercially available components has proven to be significantly more challenging than originally assumed. Citing price or timing issues, the majority of manufacturers approached could not deliver such adjusted components within the timeframe of the project. The accomplishment of the project goals was ultimately achieved through the extensive efforts of the associated project partners that customised the available components individually. A network of companies and institutional bodies has emerged as a result of this project, which can now answer many questions on the subject of inductive energy transmission systems.