Overview
Trolley bus systems provide modern public transport for small and medium sized cities, and they supplement the public transport networks of big cities. Although extensions of trolley bus lines are more expensive compared to standard diesel bus lines, trolley buses can perform better than diesel buses concerning environmental and economic issues. Taking this into account, the next step is to implement battery systems into the trolley buses to achieve partial independence from the catenary. Since batteries need to be recharged and carry a large amount of energy (due to fast charging not being appropriate for the situation), it is worth considering the characteristics and performance of battery supported trolley buses. They are able to recharge the battery while operating under the catenary as well as to pass catenary gaps in the inner cities. In motion charging is advantageous over fast charging as it may result in a larger amount of energy transferred to the battery and in a longer battery life due to the lower charging current. Furthermore, charging the batteries in motion eliminates charging stops and related waiting times leading to a gain in productivity. Battery supported trolley buses also perform better then hybrid buses, since it turned out that the latter do not reach the expected performance in terms of energy efficiency and reliability.
The main scope of the project is to prove that battery supported trolley buses are the better option to hybrid buses and battery buses with fast charging technology. Therefore, the charging strategy in motion charging, that allows off-wire operation in remote sections of the networks, will be evaluated and tested in our partner cities. Further tasks are the assessment of composite bus frames, conceptional work on battery supported electric commercial vehicles and charging station for other vehicles, the creation tools for the evaluation and design of battery supported trolley buses.