Electric drive and charging system for heavy vehicles : Solutions based on Electric Road Systems

Sammanfattning: The electrification of road bound transport is to some extent limited by the large cost of the energy storage required on-board the vehicles, i.e., the cost of the battery. One way of reducing the required capacity of the on-board energy storage is to enable the possibility to supply the vehicles with electrical energy while it is moving, also called dynamic charging. The energy transfer is usually achieved by either an inductive or conductive coupling between the static supply and moving vehicle. This thesis focuses on a conductive energy transfer system and the challenges that follows, mainly the preference that the supply and the on-board voltage system should be galvanically isolated. A prototype electrical powertrain is developed in a laboratory environment with the purpose of proving the concept as well as gathering measurement data for model validation. The data gathered is used to model three different types of electrical powertrains, each with a different philosophy with regard to galvanic isolation, and to compare their performance from an energy consumption and battery degradation point of view. The experimentally verified powertrain of this thesis features \textit{integrated} energy transfer capabilities, meaning components originally only meant for traction purposes are also utilized in the process of transferring energy from an external supply to the wheels and energy storage on-board the vehicle. It turns out that this approach to energy transfer can be shown to be beneficial under certain circumstances, such as vehicle type, electric road characteristics for instance, compared to a \textit{separate} energy transfer solution, where one separate component has, as its only purpose, the responsibility to transfer energy from a supply to the wheels and energy storage.