In this work, the electromechanical system of the 8000-series of Athens trolleybuses, based on data provided by OSY S.A., is analyzed. Those data were used to develop a valid model in order to estimate the total energy consumption of the vehicle under any possible operating conditions. In addition, an effort is made to estimate the energy saving potential if the wasted energy—in the form of heat—during braking or downhill courses is recovered (regenerative braking) and retrofitted during normal operation. This process requires the installation of appropriate electrical apparatus to recover and temporarily store this energy amount. Moreover, due to the fact that the main engine of the system is an asynchronous electric machine, its driving scheme is also of interest. This study assumes the current driving scheme, that is the direct vector control (DVC), and proposes an alternative control method, the direct torque control (DTC). Energy consumption/saving calculations highlight the effectiveness of incorporating regenerative braking infrastructure in trolleybuses transportation systems. Finally, a sustainable hybrid energy storage unit that supports regenerative braking is proposed.

In this paper, a flexible interlinking dc/dc converter with enhanced FRTC is proposed to satisfy the advanced requirements of modern on-board DC MGs; the topology uses a non-isolated switched capacitor-type multilevel converter in combination with a cascaded step up/down converter to facilitate the incorporation of various types of energy storage and/or production units in a DC MG. Overall, a high voltage conversion ratio between the dc bus of the MG and the power unit is achieved. The proposed configuration facilitates the CCM operation of both the power unit and the DC MG and it is characterized by bidirectional power flow capability, enhanced FRTC, zero switching losses for the multilevel converter, limited complexity of the control scheme (compared to the counterpart multilevel solutions) and low real-time communication demands, corresponding so to the increasing flexibility needs of the EMS of modern MGs. The mathematical analysis and the dynamic performance of the control scheme of the proposed topology concept are evaluated via MATLAB/Simulink simulations and real-time CHIL tests, with the use of a 1202 dSPACE platform and an external dsPIC30F4011 microcontroller.

In this work, the development of an energy recovery control unit to be incorporated in the light-emitting diodes (LEDs) lighting systems of heavy-duty vehicles is presented. This innovative industrial product adopts modern power electronics technology to improve existing trucks’ LED lighting system by eliminating the so far inevitable power consumption by the conventional central control unit of the majority of these vehicles, which is obligatory for the uninterruptable operation of their lighting system. The main idea of this innovative product is its capability to virtually increase the lighting system power consumption without actually consuming this amount of energy, thus facilitating the central control unit requirements regarding these vehicles in an energy-conscious way. Under this light, a mature power converter’s topology is employed to draw the proper amounts of power from the vehicle’s batteries supply, to the level that the central control unit recognizes, and return this energy back to the batteries. The tests results of the developed industrial product highlight the energy saving potential of the proposed energy recovery scheme, while the Life Cycle Cost Analysis (LCCA) results confirm its techno-economical and environmental profit for the truck applications under study.