Comparison of Different Powertrain Structures Intended for a Hybrid Skidder

Hybrid powertrain presents a viable solution for reducing fuel consumption achieved by a powertrain electrification while maintaining the independence from the electric grid or a charging station. Due to the fact that skidders belong to the class of forestry machinery which is intended for field use, this operating independence is very important. A simple backward-looking model of a series hybrid powertrain skidder is developed and presented in this paper. The model is then simulated over a number of previously-defined operating missions which include realistic track slopes and variable loads. The results are compared with the results of conventional and parallel hybrid powertrains proposed in previous works. Simulation results show that 17% fuel efficiency improvement is obtainable with the proposed series configuration over the conventional skidder in skid trail driving. Finally, the return of investment period of series hybrid and parallel-hybrid configurations are compared, and their respective advantages and disadvantages are listed and discussed.