A modular switching system as a flexible charging solution for a logistics terminal

Sammanfattning

The ambition to move road transport from fossil fuels to electric energy is a large undertaking. One of the biggest challenges with making the trucks fully electric is to charge them. They are usually operated daytime, and the operations gives very little time for charging resulting in the power needed for daytime charging being in the high 100s of kW. A desired system implemented at the terminal would be a flexible system which provides charging in different power levels at different charging spots, matching the charging power needed of each individual truck charging at any given time. This thesis investigates a modular switch matrix charger, using Elonroads electric road system as stationary charging ports, as a solution to charge a larger logistics fleet and compares it in flexibility, robustness, and costs to a more conventional fast charger model. The modularity stems from the charger being built with several dc-dc converters where each is connected via a switch matrix to each charging port. This enables the charger to divert as many converters as needed to every charging port in a flexible way, providing each charging spot with the unique power level each truck desires when charging. In the thesis a small scale prototype is also constructed to prove the switch matrix concept as a working solution. The results shows that the charger with a switch system is a cheaper alternative, mainly due to the fewer numbers of DC-DC converters needed, while still being a more flexible and robust system compared to the conventional fast charger system. The cost of the switch model is heavily based on the number of switches in the system which correlates to the size of the whole structure. The small scale prototype also proved that the switch system is feasible to build.